Columbia River Project Water Use Plan

Transcription

1 Columbia River Project Water Use Plan KINBASKET AND ARROW LAKES REVEGETATION MANAGEMENT PLAN Reference: CLBMON-33 Arrow Lakes Reservoir Inventory of Vegetation Resources ADDENDUM TO 2007 FINAL REPORT Study Period: 2007 Delphinium Holdings Inc., Castlegar, BC

2 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report Original Report Cover Arrow Lakes Reservoir Inventory of Vegetation Resources ADDENDUM TO 2007 FINAL REPORT Submitted to: BC Hydro Water License Requirements Castlegar, BC by: Katherine Enns, RPBio., MSc. CCEP Ryan Durand, BSc., RPBio. Pascale Gibeau, MSc. and Bruce Enns, BSc. Delphinium Holdings Inc. 602 Tamarack St. Castlegar, B.C. V1N 2J2 December 17, 2007 Delphinium Holdings Inc. ii

3 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report Citation: Enns, K.A., R. Durand, P. Gibeau & B. Enns Arrow Lakes Reservoir Inventory of Vegetation Resources (2007) Addendum to 2007 Final Report. Report prepared by Delphinium Holdings Inc. for BC Hydro. Cover photo: Lower Revelstoke Reach 2007 BC Hydro No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior permission from BC Hydro, Burnaby, B.C. Delphinium Holdings Inc. iii

4 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report EXECUTIVE SUMMARY BC Hydro has requested an inventory of vegetation resources of the Arrow Lakes Reservoir (CLBMON-33). The inventory is a landscape level analysis of vegetation community changes over time in response to BC Hydro s soft constraints operating regime. The study focuses on changes in the existing vegetation communities in the reservoir drawdown zone between elevations 434m and 440m and uses a combination of aerial photographic interpretation at 1:5,000 scale, and field measurements in biomonitoring plots. This report describes the results of the field work for the first year of this program, and is presented as an addendum to the 2007 Final Report (Enns 2007b). Field work for this project was done at the species level in order to characterize the landscape level vegetation community types. While field work for the landscape level vegetation inventory program for the Arrow Lakes Reservoir was originally schedule for June 2007, it could not be carried out due to high water levels in the reservoir. Instead, field work was completed between Septebmer and October of The objectives of Arrow Lakes Reservoir Inventory of Vegetation Resources are to: Identify and spatially delineate existing riparian and wetland vegetation communities within the drawdown zone; Measure the spatial extent, structure and composition (i.e. distribution and diversity) of the communities in the drawdown zone at repeated time intervals over a 10 year period; Assess whether there are changes in the spatial extent, structure and composition of the communities in the drawdown zone over the monitoring period; Assess whether observed changes in the spatial extent, structure and composition are attributable to the soft constraints operating regime of the reservoir; and, Provide information on the effectiveness of the soft constraints operating regime at maintaining the existing spatial extent, structure and composition of the communities in the drawdown zone at the landscape level. The interpretation of the API and the field measurements must be analyzed using biometrics to address the following hypothesis and associated sub-hypotheses: H 0 : Under the soft constraints operating regime (or possibly a newly selected alternative after five years), there is no significant 1 change in existing vegetation communities at the landscape scale. 1 A significant change in vegetation can be viewed as any measurable change, and the emphasis can be on the magnitude of the change, and how much of the change can be attributed to the soft constraints operating regime. Delphinium Holdings Inc. iv

5 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report H 0A : H 0B : There is no significant change in the spatial extent (number of hectares) of vegetation communities within the existing vegetated zones of Arrow Lakes Reservoir. There is no significant change in the structure and composition (i.e. distribution and diversity) of vegetation communities within the existing vegetated zones of Arrow Lakes Reservoir. The inventory of vegetation resources of the Arrow Lakes Reservoir (CLBMON-33) has resulted in 1:5,000 scale mapping and landscape level vegetation classification and habitat suitability mapping for eight wildlife taxa. A series of initial monitoring plots have both provided data but have also been established to show changes over time in response to the reservoir s soft operating constraints. The statistical analyses of the field data were used primarily to examine the field data for trends in the vegetation community composition. Sampling was concentrated on 171 plots, covering the length of the reservoir, in which 188 plant species were observed. The results of the mapping analysis show that the vegetation of the Arrow Lakes Reservoir was generally uniform. The vegetation was dominated by a few species, and Reed Canary Grass (Phalaris arundinacea) was the most frequent. The vegetation was sparser, but taller and richer in the high elevation plots. Vegetation covers and heights increased with slope, except on very steep slopes. These results correspond to observations in the field: the field transects showed sparser, drier, but richer species compositions at high elevation, followed by dense cover of reed canary grass and associated species as the transects reached the lowest elevation. It is expected that the inundation regime, as well as terrain texture, terrain stability, coarse fragment content, water availability and effects of scouring will help to explain variation in vegetation spatial extent (i.e cover), species composition and height. Broad differences in vegetation cover, median vegetation height and frequencies of map units of different community types were observed between the Arrow Lakes portion of the reservoir and the Revelstoke Reach portion. A common issue observed throughout the study area was a difference in vegetation heights and covers between the time the air photos were taken (May 2007) and the time that field observations were made in September and October In some areas, air photos were almost devoid of vegetation in May, while sample plots observed in October indicated a much higher percent cover of vegetation. This discrepancy likely resulted in a number of polygons being typed inaccurately (e.g. considered to be primarily BE gentle unvegetated beach instead of PC reed canary grass) or deciles that under represent the component of vegetated polygons. This problem can be reconciled by flying the photographic surveys much closer to the time that field work is conducted. Habitat suitability for wildlife is generally greatest in the Revelstoke Reach, Beaton Arm and middle Narrows portions of the Arrow Lakes than in other parts of the reservoir. Use by Canada Goose, elk, coyote, white-tailed deer and black bear is at times very heavy throughout the reservoir. Delphinium Holdings Inc. v

6 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report Recommendations include the following: Coordinate the field sampling and aerial photography to take place as close together in time as possible during low water; Select representative sites from the existing database to show changes in vegetation spatial extent (i.e. cover), species richness and heights over time. Conduct field sampling in selected monitoring plots in the spring of 2008 to determine the species compositions, heights, and covers for comparison with the spring-flown imagery. Conduct chage analysis of the cover of vegetation community types within the mapped polygons, year wise. These changes will be in proportions of vegetation community types within polygons, and changes in total areas of each vegetation community type over time. Delphinium Holdings Inc. vi

7 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report ACKNOWLEDGEMENTS We would like to acknowledge the advice and project management of Eva Boehringer, Pat Vonk, Gary Belcourt and Les Giles of BC Hydro. The author had many discussions with Emily Robertson of Robertson Environmental Services Ltd. These were important to the aerial photographic interpretation and draft classification stage of this phase of the project. Sid Tsang, of Tsang Geoscience provided advice on the classification of shoreline features in the drawdown zone. Adolf Ceska of Ceska Geobotanical will provide identifications for species of Cyperaceae. Michael Keefer of Keefer Ecological Services conducted fieldwork in Revelstoke Reach. Geoff Tomlins of Pacific Geomatics Ltd provided advice on the use of image analysis. Our thanks to them all. Delphinium Holdings Inc. vii

8 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report TABLE OF CONTENTS 1.0 Introduction Background Study Area Physiography, Geology and Soils Climate Biogeoclimatic Ecosystem Classification Archaeological and Heritage Sites Water Levels Land Use Wildlife Suitability Mapping Methods Overview Aerial Photography Interpretation Digital Elevation Model Map Creation and Database compilation Community Type Mapping Wildlife Habitat Suitability Mapping Quality Assurance / Quality Control Map Analysis Field Data Collection Data Analysis Variables and analytical units General parameters and graphs Multiple regression models Comparison of Arrow Lakes and Revelstoke Reach areas Cluster analysis Wildlife Habitat Assessment Species at Risk Results Description of the Vegetation Community Types RS Willow - Red osier dogwood - Stream entry RR Rush Wet sites/ seepage/rill PO Waterlily - Potamogeton open water PE Reed Canary Grass - Horsetail middle to lower elevation PC Reed Canary Grass - Lenticular Sedge mesic PA Reed Canary Grass - Redtop dry upland shedding sites LO Blue wild rye - log zone RH Red-top Hare s foot clover upland CR Cottonwood riparian CL Saskatoon - rock or cliff upper elevation IN Industrial / Residential/ Recreational WR Silverberry river BB Non-vegetated boulders, steep BG Sparsely-vegetated boulder flats SS Non-vegetated Sand and/or gravels, steep BE Beach Non-vegetated flat sands Distribution of the Community Types Description of the Vegetation with the Field Data Distribution of variables Delphinium Holdings Inc. viii

9 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report Variation in vegetation cover Variations in vegetation height Variations in species richness Differences between Areas in the Arrow Lake vs Revelstoke Reach Description of Vegetation Patterns Wildlife Use and Habitat Suitability Assessment Species at Risk and Species of Importance Vegetation Wildlife Land Use Issues Discussion Limitations of the Study Conclusions Recommendations References LIST OF APPENDICES Appendix 1 - Vegetation Species List...91 Delphinium Holdings Inc. ix

10 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report LIST OF FIGURES Figure 1. Revelstoke Reach, looking north from the southern opening to the reach toward Revelstoke, B.C. Image from Google.com with permission...4 Figure 2. Study area physiography from Galena Bay and Shelter Bay in the north to the alluvial fan at Nakusp. Image from G. Tomlins with permission...5 Figure 3. The lower section of the Arrow Lakes from the Narrows to Hugh Keenleyside Dam in the southeast corner of the image. A section of winter imagery is patched into the summer image, which shows snow-lie on the ridges at high elevation on the eastern shore in the Selkirk Mountains. Image from G. Tomlins, with permission....6 Figure 4. Surficial geology of the study area (Fulton 1995)...7 Figure 5. Location of the five BEC variants found within the study area. Data from the BC Provincial BEC maps...9 Figure 6. Arrow Lakes Reservoir water levels (expressed as metres a.s.l. elevation) during aerial photo capture and field work. Yellow box indicates photo capture, green and red boxes are the earliest and latest dates of field work. Water level data provided by BC Hydro on October 19, Figure 7. Location of and approximate breaks between geographic areas...19 Figure 8. Example of mapped community types. This map shows the polygons mapped in Line 43 in Revelstoke Reach with the legend indicating the community type, or types, identified for each polygon...23 Figure 9. Representative photo of the RS community type Figure 10. Distribution (expressed in total hectares of the type) of the RS community type by geographic area...25 Figure 11. Distribution (expressed in the total number of polygons in which the type occurred) of the RS community type by geographic area Figure 12. Representative photo of the RR community type...26 Figure 13. Distribution (expressed in total hectares of the type) of the RR community type by geographic area...27 Figure 14. Distribution (expressed in the total number of polygons in which the type occurred) of the RR community type by geographic area Figure 15. Representative photo of the PO community type...28 Figure 16. Distribution (expressed in total hectares of the type) of the PO community type by geographic area...29 Figure 17 Distribution (expressed in the total number of polygons in which the type occurred) of the PO community type by geographic area Figure 18. Representative photo of the PE community type Figure 19. Distribution (expressed in total hectares of the type) of the PE community type by geographic area...31 Delphinium Holdings Inc. x

11 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report Figure 20 Distribution (expressed in the total number of polygons in which the type occurred) of the PE community type by geographic area...31 Figure 21. Representative photo of the PC community type Figure 22. Distribution (expressed in total hectares of the type) of the PC community type by geographic area...33 Figure 23. Distribution (expressed in the total number of polygons in which the type occurred) of the PC community type by geographic area Figure 24. Representative photo of the PA community type Figure 25. Distribution (expressed in total hectares of the type) of the PA community type by geographic area...35 Figure 26 Distribution (expressed in the total number of polygons in which the type occurred) of the PA community type by geographic area...35 Figure 27. Representative photo of the LO community type Figure 28. Distribution (expressed in total hectares of the type) of the LO community type by geographic area...37 Figure 29. Distribution (expressed in the total number of polygons in which the type occurred) of the LO community type by geographic area...37 Figure 30. Representative photo of the RH community type...38 Figure 31. Distribution (expressed in total hectares of the type) of the RH community type by geographic area...39 Figure 32 Distribution (expressed in the total number of polygons in which the type occurred) of the RH community type by geographic area Figure 33. Representative photo of the CR community type...40 Figure 34. Distribution (expressed in total hectares of the type) of the CR community type by geographic area...41 Figure 35. Distribution (expressed in the total number of polygons in which the type occurred) of the CR community type by geographic area Figure 36. Representative photo of the CL community type...42 Figure 37. Distribution (expressed in total hectares of the type) of the CL community type by geographic area...43 Figure 38. Distribution (expressed in the total number of polygons in which the type occurred) of the CL community type by geographic area...43 Figure 39. Representative photo of the IN community type...44 Figure 40. Distribution (expressed in total hectares of the type) of the IN community type by geographic area...45 Figure 41. Distribution (expressed in the total number of polygons in which the type occurred) of the IN community type by geographic area...45 Figure 42. Representative photo of the WR community type Figure 43. Distribution (expressed in total hectares of the type) of the WR community type by geographic area...47 Delphinium Holdings Inc. xi

12 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report Figure 44. Distribution (expressed in the total number of polygons in which the type occurred) of the WR community type by geographic area Figure 45. Representative photo of the BB community type Figure 46. Distribution (expressed in total hectares of the type) of the BB community type by geographic area...49 Figure 47. Distribution (expressed in the total number of polygons in which the type occurred) of the BB community type by geographic area...49 Figure 48. Representative photo of the BG community type...50 Figure 49. Distribution (expressed in total hectares of the type) of the BG community type by geographic area...51 Figure 50. Distribution (expressed in the total number of polygons in which the type occurred) of the BG community type by geographic area Figure 51. Representative photo of the SS community type Figure 52. Distribution (expressed in total hectares of the type) of the SS community type by geographic area...53 Figure 53. Distribution (expressed in the total number of polygons in which the type occurred) of the SS community type by geographic area...53 Figure 54. Representative photo of the BE community type Figure 55. Distribution (expressed in total hectares of the type) of the BE community type by geographic area...55 Figure 56. Distribution (expressed in the total number of polygons in which the type occurred) of the BE community type by geographic area...55 Figure 57. Distribution of the sample plots in the the Arrow Lakes Reservoir...58 Figure Four examples of scouring at the 440 to m elevation contributing to lower cover at higher elevation...62 Figure 60. Variations in average median heights (m) and elevation of the plots (m)...63 Figure 61. Average median heights (m) are greater at highest elevation and variation is highest due to shrub growth at the highest elevation sites...64 Figure 62. Average median heights (m) are declining with decreasing elevation...64 Figure 63. Variations in richness (number of species) according to the slope of the plots (between an elevation of 434m and 440m) Figure 64. Proportions of the map units for each community type for Arrow Lakes and Revelstoke areas. * Frequencies shown for Arrow Lakes were corrected for the higher total number of map units sampled (i.e. the total frequencies of map units are equal for the two areas (1400) in this graph)...67 Figure 65. Projection in the two first axes of the ordination PCoA (19.5% and 15.5% of the variation explained, respectively) of the groups formed by K-Means partitioning...68 Figure Areas in hectares (ha) of nil, low, moderate and high habitat suitability for main taxa in the Arrow Lakes Reservoir drawdown zone between elevations 434m and 440m Delphinium Holdings Inc. xii

13 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report Figure 67. Areas with ranked song bird habitat suitability (nil, low, moderate, high) in the eleven map areas of the Arrow Lakes Reservoir. Areas are shown from lowest latitude to highest, i.e. from Deer Park to North of Revelstoke Figure 68. Areas with ranked water-fowl and raptor habitat suitability (nil, low, moderate, high) in the eleven map areas of the Arrow Lakes Reservoir. Areas are shown from lowest latitude to highest, i.e. from Deer Park to North of Revelstoke...74 Figure 69. Areas with ranked reptile habitat suitability (nil, low, moderate, high) in the eleven map areas of the Arrow Lakes Reservoir. Areas are shown from lowest latitude to highest, i.e. from Deer Park to North of Revelstoke Figure 70. Areas with ranked amphibian habitat suitability (nil, low, moderate, high) in the eleven map areas of the Arrow Lakes Reservoir. Areas are shown from lowest latitude to highest, i.e. from Deer Park to North of Revelstoke Figure 71. Areas with ranked small mammal habitat suitability (nil, low, moderate, high) in the eleven map areas of the Arrow Lakes Reservoir. Areas are shown from lowest latitude to highest, i.e. from Deer Park to North of Revelstoke Figure 72. Areas with ranked large mammal habitat suitability (nil, low, moderate, high) in the eleven map areas of the Arrow Lakes Reservoir. Areas are shown from lowest latitude to highest, i.e. from Deer Park to North of Revelstoke Figure 73. Areas with ranked butterfly / dragon fly habitat suitability (nil, low, moderate, high) in the eleven map areas of the Arrow Lakes Reservoir. Areas are shown from lowest latitude to highest, i.e. from Deer Park to North of Revelstoke...77 Figure 74. Areas with ranked snail habitat suitability (nil, low, moderate, high) in the eleven map areas of the Arrow Lakes Reservoir. Areas are shown from lowest latitude to highest, i.e. from Deer Park to North of Revelstoke Figure 75. The percentage of the IN (Industrial / Residential / Recreational) vegetation community type in each of the main eleven map areas in the Arrow Lakes Reservoir Delphinium Holdings Inc. xiii

14 Vegetation Monitoring in the Arrow Lakes Reservoir - Addendum to 2007 Final Report Table 1. Table 2. Table 3. Table 4. Table 5. Table 6 Table 7. Table 8. Table 9. LIST OF TABLES List of biogeoclimatic zones, subzones and variants present in the study area....8 The proportion of the year in which water elevations exceed predefined water elevation bands from January 1, 1990 to November 29, Data were obtained from BC Hydro and were measured as a daily average for each year Grouping of the map areas (flight lines) by geographic area in the Arrow Lakes Reservoir Summary of the areas of each of the sixteen vegetation types mapped in the Arrow Lakes Reservoir. The summary shows the total area (in hectares) of each community type as well as the number of polygons in which the type occurred Summary of the descriptive parameters of the dependent variables in the plots...59 Summary of descriptive parameters of the independent variables...59 Summary of the characteristics of each community type represented by the plots surveyed in the field...60 Summary of the characteristics of each geographic area represented by the plots surveyed in the field...60 Summary of the variations of the vegetation cover, vegetation median height and richness between areas A (Arrow Lake) and R (Revelstoke Reach) Table 10. Characteristics of the seven groups defined by the K-Means analysis. AV stands for average...68 Table 11. Species composition in each of the seven groups defined by the K-Means analysis. Number in brackets are the number of plots in the group where the specific species was encountered. The * means that species appearing only once for these groups were not included in the list to simplify the table (but were used for the computation of the partitioning) Table 12. Habitat suitability rankings (high = 3, moderate = 2, low = 1, nil = 0) for each vegetation community type in the Arrow Lakes Reservoir for the taxa grouped as song birds, shorebirds, waterfowl and raptors, reptiles, amphibians, large and small mammals, butterflies and snails...71 Table 13. List of confirmed and potential plant species from the CDC tracking lists...79 Table A1. Vegetation Species List from plots completed in the Arrow Lakes Reservoir in September 13 to October Delphinium Holdings Inc. xiv

15 1.0 Introduction BC Hydro has requested an inventory of vegetation resources of the Arrow Lakes Reservoir (CLBMON-33). The inventory is a landscape level analysis of vegetation community changes over time in response to BC Hydro soft constraints operating regime. The study focuses on changes in the existing vegetation communities in the reservoir drawdown zone between elevations 434m and 440m and uses a combination of aerial photographic interpretation at 1: 5,000 scale, and field measurements in biomonitoring plots. This addendum to the 2007 Final Report (Enns 2007b) describes the results of the fieldwork and updates for the mapping for this program in its initial phase. Landscape (large) scale mapping and vegetation analysis is not done at the species or even site series level (De Castro 2006, Anderson et al. 1976), but at the broader vegetation community level, often with terrain features included in the classification. Field work for this project was done at the species level in order to characterize the landscape level vegetation community types. This study will focus on changes at the landscape scale, even though the level of information may use decision aids typically applied to smaller scale maps, such as cross sectional drawings of community types, and species compositions of community types. More detailed site- and species specific-studies will be conducted under three additional monitoring programs, starting in The objectives of Arrow Lakes Reservoir Inventory of Vegetation Resources are to: Identify and spatially delineate existing riparian and wetland vegetation communities within the drawdown zone; Measure the spatial extent, structure and composition (i.e. distribution and diversity) of the communities in the drawdown zone at repeated time intervals over a 10 year period; Assess whether there are changes in the spatial extent, structure and composition of the communities in the drawdown zone over the monitoring period; Assess whether observed changes in the spatial extent, structure and composition are attributable to the soft constraints operating regime of the reservoir; and, Provide information on the effectiveness of the soft constraints operating regime at maintaining the existing spatial extent, structure and composition of the communities in the drawdown zone at the landscape level. The interpretation of aerial photographic images (API) and the field measurements must be analyzed using biometrics to address the following hypothesis and associated subhypotheses: H 0 : Under the soft constraints operating regime (or possibly a newly selected alternative after five years), there is no significant 2 change in existing vegetation communities at the landscape scale. 2 A significant change in vegetation can be viewed as any measurable change, and the emphasis can be on the magnitude of the change, and how much of the change can be attributed to the soft constraints operating regime. Delphinium Holdings Inc. 1

16 H 0A : H 0B : There is no significant change in the spatial extent (number of hectares) of vegetation communities within the existing vegetated zones of Arrow Lakes Reservoir. There is no significant change in the structure and composition (i.e. distribution and diversity) of vegetation communities within the existing vegetated zones of Arrow Lakes Reservoir. The above hypothesis and the research objectives form the basis for the investigation, but further relationships between the inundation regime of the reservoir and the response of the vegetation will be examined both statistically and using plant ecological analysis, where feasible over the duration of this project (see Study Design, Enns 2007a). There are two levels of analysis in this project. The mapped polygon data will show changes in spatial extent of community types over time. The field data collected within mapped polygons will show the changes in vegetation cover, species richness (used as a measure of structure and composition) and heights in monitoring plots. Species richness is fdefined as the number of species/taxa per plot. 2.0 Background The vegetation of the Arrow Lakes Reservoir drawdown zone has been influenced by water impoundment and management since the construction of the Hugh Keenleyside Dam between 1964 and Construction of the Hugh Keenleyside Dam was completed in Prior to this, the Arrow Lakes were two smaller water bodies separated by a 32 km section of the Columbia River. Inundation covered 56.9 km 2 of streams, wetlands, forests and cultivated fields (Columbia Basin Fish and Wildlife Compensation Program, undated), many of which were cleared prior to inundation. Some of these areas still have the stumps of trees and remnants of the original forested soils, including some of the original vegetation. Roads through all of the map areas are common, and they have physical characteristics of stability and compaction that have retained some roadside and ditch vegetation, but also have allowed some surficial erosion and scouring to occur. The long term trends in the reservoir indicate that a succession of occasional high water trending years has occurred before. Also, seeding and planting efforts have taken place both in the past and recently (AIM and CARR 2000). Some map areas, notably in Revelstoke Reach, have been planted with willow stakes. The results of the vegetation analysis (5.0) discuss the influence of past and current uses on the landscape level character of the vegetation ini the Arrow Lakes Reservoir. Past forest clearing, previous farming, roads and other land use also have had an impact on the vegetation character of the drawdown zone (Columbia Basin Fish and Wildlife Compensation Program, undated). The potential areas for vegetation establishment in the drawdown zone were characterized by Moody 2002, Moody and Carr 2003, and Moody 2005 (summarized in Grau and Walsh 2007). The information from these studies is mainly based on interpretation of satellite imagery to determine dominant vegetation and potential for revegetation, rather than landscape level classifications or field-based ecological characterization. Delphinium Holdings Inc. 2

17 The impact of water management on the vegetation resources of the Arrow Reservoir drawdown zone has been dramatic, but remnants of the original vegetation and soils types persist. However, it is not possible to assume that the forest classification or existing wetlands classifications available for the Arrow Lakes and Revelstoke Reach apply to the existing communities. The vegetation resources and the ecological variables that influence persistence in a reservoir environment have been described in other ecosystems (Braumandl and Curran 1992), but climate and soils vary substantially. Therefore, it is difficult to use other studies as guides for how to characterize landscape level changes in the vegetation. The usual effect of repeated inundation, as summarized from Kozlowski (1997), is the alteration, and eventual compaction of soil structure, depletion of oxygen from soils and accumulation of carbon dioxide in soils, induced anaerobic decomposition of organic matter, and reduced water soluble mineral availability in the soil nutritional profile. Also, the effect of scouring and mobilization of soils, the action of waves and currents at the interface between waters edge and soil (i.e. physical removal of vegetation), the presence or absence of fresh water supplies through ground water, the effect of inundation on seed viability, plant physiology and the various soil structural and nutritional features all have a bearing on the development and persistence of vegetation communities in the drawdown zone. Soil chemistry and plant biomass in relation to elevation were described for sites in the Revelstoke Reach portion of the reservoir (AIM and Carr 2000). The highest above ground biomass was found at 437m, whereas the highest root biomass was found at the highest elevation studied (438m). Soils analysis (Appendix 6 of AIM and Carr 2000) shows very high bulk densities, and very low total available nitrogen in soils, as well as very low carbon, indicating low organic material contents. Widlife use of the Arrow Lakes Reservoir is better known in Revelstoke Reach than in the Arrow Lakes portion. Song bird use of the reservoir was described by Boulanger et al. (2000), who surveyed birds use in an atypical low water year in the Revelstoke Reach portion of the reservoir. They recorded 54 species in cottonwood riparian forests, 47 species in willow habitats, 35 species in native grasses and 32 species in planted fall rye habitats. 3.0 Study Area The 240 km long Arrow Lakes Reservoir includes the Revelstoke Reach and the Beaton Arm and Arrow Lake sections of the Columbia River drainage between Revelstoke B.C. and the Hugh Keenleyside Dam west of Castlegar, B.C. Sections of the reservoir are being monitored in this landscape level analysis, as defined by forty-four individual map areas. The distance between the southern most site at Deer Park, north-east of Castlegar, and the Trans Canada Slough in Revelstoke is 225 km. 3.1 Physiography, Geology and Soils The physiology of the study area was summarized by BC Hydro (2007) and is described in Holland (1976). The drawdown zone lies within a large, glacially carved U-shaped trough influenced by the physiography of the Columbia Mountains, including the Delphinium Holdings Inc. 3

18 Monashee Mountain Range to the west of the Columbia River and the Selkirk Mountain Range to the east. Both ranges are north-trending, and are more massive and dramatic to the northeast and more subdued and rounded in the southwest. A mantle of deep till (glacial drift) covers the mountain sides throughout, and steeply incised creek drainages enter the reservoir throughout the length of the study area. The eastern slopes have more variable bedrock types (and therefore parent materials of soils) than the western slopes and glaciers are more common on the eastern side than the west. Figures 1, 2 and 3 show the appearance of the Revelstoke Reach, the Mid Arrow and Beaton Arm sections of the Arrow Lakes, and the southern portion of the Arrow Lakes, including the Deer Park and Renata areas that are furthest south in the study area. The figures show that the Revelstoke Reach portion of the Columbia River trough is shallow: BC Hydro (2007) describes the depths as ranging from 0.6 meters to 1.8 meters, whereas the Beaton to Deer Park sections of the Columbia are of various depths, but overall are considerably deeper than the Revelstoke Reach portion of the Arrow Lakes. Figure 1. Revelstoke Reach, looking north from the southern opening to the reach toward Revelstoke, B.C. Image from Google.com with permission. Figures 1 through 3 illustrate the steepness of the creek draws leading into the reservoir on the eastern side and the larger number of creek drainages on the eastern shore of the drawdown zone. These figures also show that deposition of till is deeper and more gradually deposited, and possibly thicker on the western (Monashee Mountains) side of the study area. Delphinium Holdings Inc. 4

19 Figure 2. Study area physiography from Galena Bay and Shelter Bay in the north to the alluvial fan at Nakusp. Image from G. Tomlins with permission. Delphinium Holdings Inc. 5

20 Figure 3. The lower section of the Arrow Lakes from the Narrows to Hugh Keenleyside Dam in the southeast corner of the image. A section of winter imagery is patched into the summer image, which shows snow-lie on the ridges at high elevation on the eastern shore in the Selkirk Mountains. Image from G. Tomlins, with permission. The study area has a diverse surficial geology due its relatively large area and complex bedrock geology and glacial action (Figure 4). The primary components are veneers and blankets of thick, continuous till with extensive rock outcrops. These deposits were formed by glacial action and are composed of various combinations of silt, clay and a clayey diamiction. Smaller areas interspersed throughout the study area are composed of colluvial deposits, rock and glaciolacustrine and/or lacustrine deposits. Colluvial deposits are generally blocks and rubble with sand and silt that are derived from crystalline bedrock, metamorphic substrates and cemented sandstones. These deposits are residual materials deposited in veneers and blankets from downslope movement where bedrock has disintegrated. Rock outcrops are characterized as complexes of rock, colluvium and till from alpine and glacial landforms. These are common in the southern portion of the reservoir. The glaciolacustrine and lacustrine deposits are generally composed of fine grained silt and clay with localized deposits of stones. These are common in the northern portion of the reservoir. Delphinium Holdings Inc. 6

21 Figure 4, adapted from the Geological Survey of Canada, Map 1880A (Fulton, 1995) shows the previously mentioned surficial materials. The map can be interpreted using the following codes with the map colours listed in brackets: Ra (red) Alpine complexes: rock, colluvium, and till; rock and quaternary deposits complex in an area, characterized by alpine and glacial landforms. fl (purple) Fine grained: silt and clay, locally containing stones; deposited as quiet water sediments bc (brown) Colluvial blocks: blocks, and rubble with sand and silt; derived from crystalline bedrock, medium grade metamorphic substrate, and cemented sandstone. Tv (green) Till Veneer: thin and discontinuous till; may include extensive areas of rock outcrop. Tb (green-blue) Till blanket: thick and continuous till Figure 4. Surficial geology of the study area (Fulton 1995). Delphinium Holdings Inc. 7

22 Soil development in the drawdown zone of the study area was not assessed through soil pits in the field due to First Nations archeological concerns. Valentine et al. (1986) described the soils of the study areas as primarily Dystric Brunisols with a very small component of Humo-Ferric Podzol in the immediate vicinity of Revelstoke. It is assumed that soil development is limited due to the high level of disturbance and constantly changing water levels in the reservoir and likely not consistent with typical soil classifications, but the basic bedrock geological information may persist in depositional materials affecting plant growth and species composition. 3.2 Climate The climate of the study area varies considerably from south to north. To the south, just north of Castlegar, average annual temperatures are higher and precipitation (especially in the form of snow) is considerably lower than the northern portion of the study area. The average annual temperatures, maximum and minimum temperatures, annual precipitation, and annual snow fall were obtained from Environmental Canada s Climate Normals & Averages 1971 to 2000 for Castlegar, Nakusp and Revelstoke. These data, presented below, provide an indication of the general climate of the study area and the consistent variability from south to north: Castlegar (Hugh Keenlyside Dam): Daily average temperature of 8.6 C with a maximum high of 39.0 C and maximum low of C. Annual precipitation is an average of 635.2mm with 116.9mm occurring as snow. Nakusp: Daily average temperature of 7.7 C with a maximum high of 37.0 C and maximum low of Annual precipitation is an average of 842.0mm with 192.1mm occurring as snow. Revelstoke (Airport Road): Daily average temperature of 6.9 C with a maximum high of 37.2 C and maximum low of C. Annual precipitation is an average of 945.7mm with 424.7mm occurring as snow. 3.3 Biogeoclimatic Ecosystem Classification The study area is primarily situated within the Arrow Boundary Forest District. A small portion of the north end falls within the Columbia Forests District. Two biogeoclimatic zones occur within the study area: the Interior Cedar Hemlock (ICH) and Interior Douglas-fir (IDF) (Figure 5). The majority of the study area falls within the ICH and is represented by three subzones and four variants (Table 1). IDF is restricted to the southernmost portion of the study area and contains a single subzone (IDFun). The subzones are a direct reflection of increasing precipitation from the dry southern slope of Deer Park to the wet forests near Revelstoke. Table 1. List of biogeoclimatic zones, subzones and variants present in the study area. Zone Subzone Variant(s) ICH dw (dry warm) 1 ICH mw (moist warm) 2 & 3 ICH wk (wet cool) 1 IDF un (undifferentiated) Delphinium Holdings Inc. 8

23 Figure 5. Location of the five BEC variants found within the study area. Data from the BC Provincial BEC maps. Delphinium Holdings Inc. 9

24 3.4 Archaeological and Heritage Sites It is beyond the scope of this document to discuss the archaeological significance of the individual map areas. Because of the potential for disturbing sites of archaeological or heritage significance, no soils pits were done and no soil samples were taken for this phase of the study. 3.5 Water Levels Table 2 shows the percentage of the year in which water levels exceeded one metre elevation bands from m to m a.s.l. The table was generated using daily BC Hydro water level data from January 1, 1990 to November 29, As the data for 2007 were not complete, the table will likely change in subsequent years. The table was created by analyzing the 18 years of data with the use of the software program called Crystal Reports. Scripts were written to determine the number of times in each year when water levels fell within the predefined elevation bands. The number of times the level was exceeded was then summed and divided by the total number of days in the year. Those data are presented in the table as a percentage of the year in which the water level fell within a given elevation range. As well, each of the lower elevation bands also contains the percentage of time that the water level exceeded all of the higher bands. Therefore, band 1 contains the percentage of the year in which the water level was between 433 to 440m, band 2 contains percentages from 434 to 440m, and so on. Table 2. The proportion of the year in which water elevations exceed predefined water elevation bands from January 1, 1990 to November 29, Data were obtained from BC Hydro and were measured as a daily average for each year. Band Elevation Band Average Delphinium Holdings Inc. 10

25 3.6 Land Use As mentioned previously, patterns of land use existed in the study area prior to creation of the reservoir, including agriculture, grazing, forestry, rural settlement, both incidental and residential, as well as recreational use. Present use has been modified by the reservoir s operation, and the emphasis in land use has shifted dramatically from multiple uses to mostly recreational and agricultural use. Recreational use includes fishing, swimming, hiking and vehicle use. The influence of motorized recreation (ATV and other vehicle use) likely includes the following effects: Introduction of weed species from higher elevation to lower elevation areas with more well drained soils; The physical spread of species tolerant of extreme soil water fluctuation and/or flooding where vehicles have traversed through flooded areas; Some increase in erosion and mobility of materials; and, Compaction and retention of seed beds through road use. All of the above have been, and likely continue to be, important influences on the development of vegetation communities. Existing agricultural use is limited to cattle and horse grazing in brief autumn periods of low water. There is almost no forestry or agricultural use at present. These past and present use patterns have had an impact on the development of the vegetation communities and in the retention of some of the vegetation. 3.7 Wildlife Suitability Mapping Wildlife habitat use patterns were reviewed from lists generated for each biogeoclimatic variant (Stevens 1995), but these lists are wide-reaching and do not apply well to the drawdown zone. Previous song bird surveys were reviewed (Boulanger et al. 2000), but they apply to the Revelstoke Reach portion only. Wildlife suitability mapping for the study area, to be provided in a map folio, was developed from the vegetation community type mapping by creating simple algorithms for high, moderate, low and nil wildlife use across eight taxa. Incidental wildlife records were also taken in the field from September 13 to the October 11, This level of survey is insufficient for providing detailed species lists of wildlife habitat use; however, wildlife studies will be included in separate programs as part of the implementation of the Columbia River Water Use Plan. In general, wildlife use patterns in the map areas include song bird use of riparian forests, shorebirds and ducks use of open beach areas and creek entries, ungulate access for water and forage and amphibian use of standing water in potholes and back channels. A total of 53 species were noted in the field, either from bird song, tracks, scat, hair, bones, etc., or actual sightings. These records were used to assist in the development of the suitability mapping. Delphinium Holdings Inc. 11

26 4.0 Methods 4.1 Overview This project was influenced by timing of the delivery of the aerial photography and the timing of reservoir filling and drawdown. Figure 6 shows the timing of the aerial photography and the subsequent field work, which influenced the analytical and mapping results, as discussed below. Figure 6 shows that the water levels during the aerial photographic capture were at 434 meters elevation on May 30 to 31, The contract to start on the analysis was let in early June of 2007, after the reservoir had reached full pool. The field sampling occurred between September 12 and October 5, 2007 when the water levels ranged from m to m. Figure 6. Arrow Lakes Reservoir water levels (expressed as metres a.s.l. elevation) during aerial photo capture and field work. Yellow box indicates photo capture, green and red boxes are the earliest and latest dates of field work. Water level data provided by BC Hydro on October 19, 2007 Delphinium Holdings Inc. 12

27 4.2 Aerial Photography Interpretation There are a total of forty four (44) map mosaic areas identified by BC Hydro in the Arrow Lakes Reservoir, based on previous work (Moody 2005). The areas range in size and complexity from a small island of approximately 25 hectares, situated off-shore in Arrow Lake, to very large, complex, areas of several hundred hectares in Revelstoke Reach. The small island was captured on one aerial photograph, the complex area in Revelstoke Reach was captured in three lines of photographs, including the end photographs of adjacent lines. The areas were mapped separately as individual mosaic bases. The mosaics were overlaid with the BC Hydro digital elevation data (DEM); however, the 440m line was not completely captured in the sectional DEM provided by BC Hydro. Infill delineation was required. A completed version of the DEM was provided by BC Hydro on November 21, Line delineation was used to define individual land cover/vegetation types in the photographs using stereoscopic interpretation, as described in Enns 2007b. During the process of the delineation, a draft aerial photographic interpretation of the vegetation patterns was compiled. A list of the biophysical variables thought to influence vegetation in the drawdown zone was assembled, as evidenced from the patterns seen in the aerial photography. Examples included creeks entering the reservoir, the stability of terrain or surficial materials, the influence of debris, etc. These patterns were discussed with BC Hydro and the statistician assisting with the statistical design of the study, as well as with other vegetation ecologists with experience in vegetation response to disturbance from flooding. Previous to this project, the vegetation of the Arrow Lakes Reservoir drawdown zone had been described in general terms (i.e. grass, sedge, horsetail types), with only dominant species mentioned (Moody 2005). Although soil chemistry and biomass measurements of generic vegetation are available (AIM and Carr 2000), there appears to be no previous descriptions of the influence of physiography, influences from stream inputs to the reservoir, or influences of terrain textural features on vegetation retention. These factors have been shown to be important in retention of riparian vegetation over the long term (Keser 1976; Schwartz 1982; Ralston 2005; Folger et al. 1996). Using the field data and the results of the aerial photographic interpretation, a landscape level classification of the land cover types was compiled, which is presented in detail in Section 5.1 below. The vegetation type and terrain feature descriptions that have been used in the development of the classification are based on the 2007 aerial photographic interpretation and fieldwork, and may be refined and adjusted in future years based on results of further field work. For landscape-level mapping, standard height classes (from Describing Ecosystems in the Field, 1998) were used as follows: 1 sparse/bryoid 2 graminoid, aquatic, herb, dwarf shrub 3 low shrubs (<2m) and tall shrubs (2-10m) 4 pole sapling 5-7 young, mature and old forest. Delphinium Holdings Inc. 13

28 For the purpose of base mapping of landscape level features, it is possible to apply these classes to the vegetation types used in the classification; however, these height classes will not allow for accurate measurements of the change in vegetation height in polygons over time. The field measurements taken in the fall of 2007, using measuring sticks in the field for each species in the plots, has provided a measure of the variation in heights in each species in each mapped vegetation type. However, there is a difference in the heights between the aerial photography and the field measurements; the vegetation grew substantially and not evenly between May and the September-October sampling period, even though the vegetation was submerged. Therefore, it will not possible to use the field measurements as a reference for the heights as expressed in the aerial photography from Spring sampling and better correspondence between the flight and field times will be necessary to have useful height data in future. A list of the mapped attributes, to be examined as variables in the analysis, is shown in Section 3.0 of the Study Design (Enns 2007a). Features, such as leading and associated species compositions, terrain textures, slope, aspect, in-flow stream type and behavior, moisture and nutrient regimes, etc., has been identified in each polygon of the final mapping. 4.3 Digital Elevation Model The raw DEM mass points and breaklines provided by BC Hydro were used to create a triangulated irregular network digital elevation model (TIN DEM) using ESRI 3D Analyst software version 1.0. The compilation of mass points and breaklines from aerial photograph were provided by BC Hydro s Transmission Engineering Photogrammetry Services. The files provided allowed for the creation of the DEMs as separate entities for each of the flight lines. When the second set of raw DEM data with more extensive coverage of the reservoir was provided in August of 2007, a single large TIN was created. This second TIN was used to generate the 1-metre contours used in the landscape-level vegetation community type mapping with the 3D Analyst software. 4.4 Map Creation and Database compilation Community Type Mapping To create the map base, a second round of aerial photographic interpretation was used. Each polygon in each of the map areas was viewed in stereoscopic vision on the aerial photographs. The vegetation community type in each polygon was named using the landscape level classification two letter code, with up to three types possible for a polygon, and cover of that type recorded as a decile (i.e. increments of 10) in a spreadsheet linked to the GIS. A combination of field data and experience were used to decide on the presence of a vegetation community type in a polygon, including the use of cross sectional drawings of the type, written descriptions, photographs, and field experience with the appearance of a type. Further, the field data was used to verify the mapped classification. Height classes were assigned to the polygon using the same method as Hawkes et al. (2007) to allow future comparisons to be made between the Arrow Lakes Reservoir Vegetation Inventory and the Kinbasket Reservoir Vegetation Inventory. Delphinium Holdings Inc. 14

29 4.4.2 Wildlife Habitat Suitability Mapping Each polygon in the map can have up to three different vegetation community types present in different proportions; consequently, the wildlife habitat suitability ratings for each of the taxanomic groups in each polygon were calculated based on the following formula: ((Decile1/10) * HSR1) + ((Decile2/10) * HSR2) + ((Decile3/10) * HSR3) = PolygonHR where Decile1, Decile2, and Decile3 are the proportions (in tenths) of the dominant vegetation type (Type 1) in the polygon, and Type 2, Type 3, respectively, if present, and HSR1, HSR2, and HSR3 are the habitat suitability ratings of Type 1, Type 2, and Type 3 respectively for the taxanomic group under consideration, and PolygonHR is the habitat rating for the entire polygon. In cases where the polygon has only 1 vegetation type, deciles 2 and 3 would be 0 and the polygon would be rated solely on the suitability of type 1. Similarly for polygons with 2 types, decile 3 would be 0 and the suitability for the polygon would be based on only the first two terms in the summary equation. 4.5 Quality Assurance / Quality Control Several opportunities for QA/QC occur in mapping. Map errors can be interpretive, numerical, mechanical and electronic. Prior to the naming process for a given mosaic, the errors in delineation were corrected. For example, polygons were occasionally split or joined or extra lines could be added to the delineation, while some lines needed to be shifted or refined if the number of vertices were insufficient in the heads-up delineation of the linework. Once the data for the polygon database were entered, the mapping was corrected. The data were checked in GIS for errors in polygon names, deciles not adding to 10, etc. Further, inconsistencies in the mapping were checked by in-house correlation. Sections of the mapping were reviewed and suggestions for changes made depending on field experience in a given polygon, or differences of opinion. QA/QC of the air photo interpretation was conducted using two methods. First, community types identified in the field from sample plot data were compared to interpreted results. Interpretation was then adjusted based on the plot data as required. Second, two ecologists interpreted the same lines in a variety of areas. Results of the independent classifications were compared and discussed to ensure that interpretation was a consistent as possible. The accuracy of the DEM was assessed by comparing it to a precision GPS system. The system, a Trimble Pathfinder Pro XR (backpack receiver, powered antenna and TSC1 datalogger running Asset Surveyor), was compared to a BC land surveyor benchmark in Delphinium Holdings Inc. 15

30 Castlegar for spatial and vertical accuracy. Results of the test 3 found that under ideal conditions, the GPS is accurate to +/-0.1m horizontally (spatial) and +/- 0.28m vertically (elevation). This accuracy was obtained using real-time differential correction in the field with a minimum of four satellite vehicles, a Percent Dilution of Precision (PDOP) of 4 or less, and an elevation mask of 15. The Trimble Pathfinder data set was compared to the corresponding DEM elevations. 4.6 Map Analysis Summaries of the mapped vegetation community types were compiled using GIS. Areas covered by each type and general patterns in the distribution of types were examined using simple data summaries only (see Section 4.7.1). Patterns in the distribution of types between the mapped areas and between the Revelstoke Reach and Arrow Lakes portion of the study area were examined (see Section 4.9.4). The map analysis planned for in Enns (2007a) describes in detail the planned analysis and interpretation that can be done once additional variables are compiled. 4.7 Field Data Collection The purpose of field sampling in this program was two-fold with respect to the use of aerial photographic interpretations and the subsequent data analysis. Field sampling was required to: a) correct the draft classification of the vegetation community types / land cover classes; and, b) establish monitoring plots to provide data on the structure and composition of the mapped community types to assess the long-term response of vegetation to the reservoir s operating regime. Field sessions to correct the classification were done prior to the polygon naming. The creation of the map database commenced in parallel with the fieldwork, and continued until the completion of the addendum to the 2007 Final Report (Enns 2007b). Complete stratification and random sampling of polygons was undertaken in the fall of 2007 to complete the first set of field monitoring data. During these field sessions, individual polygons representing vegetation community cover types / land cover classes were sampled to identify the leading species and the community type / land cover class species composition. The use of stratified random sampling to obtain vegetation data for analysis was described in the Study Design (Enns 2007a). The mosaic numbers (1 through 44) were selected for truthing by using a random number generating technique (Zar 1974). Polygons for truthing in the field were also selected at random for each randomly selected mosaic area. In order to show the variation with elevation, transect lines were run from either upslope or downslope within a polygon, depending access to the polygon. For example if the polygon was accessed from a road, it was run from highest 3 The tests used to determine the vertical and horizontal accuracy was obtained from the University of Texas Environmental GIS course material. Available at: Delphinium Holdings Inc. 16

31 elevation to low elevation. If accessed by water, the transect was run from low to high elevation. Although the polygons were chosen at random, the beginning of each transect in the polygons was chosen to reflect the maximum variation in vegetation types within the polygon that could be seen in the field. Plots were established at the start of the transect, and were arranged linearly at 20 to 40 meter distances along the transects, depending on slope. Plots were 10 meters by 10 meters in size. The number of plots within a polygon was a function of the size of the polygon, and the size of the mosaic area, slope and distance. The most important variables collected in the field were as follows: location data and UTM coordinates, structural stage (which relates to total median height of vegetation in the plot), substrate and terrain features, slope class, disturbance type, terrain texture class and species lists, including total cover in the plot, and minimum and maximum height of each species. The number of landscape level vegetation types that were sampled and the number of representatives of each type was determined following a preliminary screening of the data. While in the field it was noted that the PC (mesic) type was being sampled in access of any other type due to its commonness. Therefore, additional representative sampling was done in other types in order to describe their landscape level features in the map classification. 4.8 Data Analysis Variables and analytical units Statistical analysis of the field data was used primarily to examine the field data for trends in the vegetation community composition, to be used as a benchmark for future monitoring in the reservoir. The analysis is preliminary, because not all of the physical variables, such as terrain textures, coarse fragment contents, stream entry notation, etc., are currently available. These variables will be examined in future trend analysis. Along general descriptive parameters, statistical analyses were therefore used to broadly identify patterns in species composition and characterize the reservoir in term of its vegetation communities and physical characteristics. Dependent and independent variables were recorded for each plot in the field or computed from the GIS. Dependent variables described the vegetation community observed at each plot, while independent variables describe physical factors that may influence the distribution and abundance of vegetation communities. These data and the results of the analyses will be used for the long-term monitoring of the vegetation community and to track changes in vegetation communities over time. Five dependent variables were used to describe the vegetation community of each plot. In the field, all genera and species, percent covers and heights were recorded, although some species were not possible to confirm due to late sampling and alterations to the structure of the plants caused by frequent and periodic inundation (Kozlowski 1997). A median vegetation height for each plot was calculated based on weighing the maximum and minimum heights for each taxon by their proportional coverage. Median height was defined as the average of the minimum and maximum heights and was used in the analysis to represent the vegetation height observed in each plot. From these Delphinium Holdings Inc. 17

32 data, presence/absence of species/taxa was compiled and richness was computed. Species richness was defined as the number of species/taxa per plot. Note that It is not possible to use species diversity statistics when counts of individuals are not taken. Five independent variables were also used in the analyses. UTM coordinates were entered into an elevation model in GIS to compute the elevation, slope and aspect of each plot. To describe the vegetation observed in the field, three different scales may be used: the plots themselves (the smallest analytical unit), the community types (defined on the map for each polygon where the plots are situated) or the geographic area (where each plot is located). The geographic areas are groups of map areas in similar locations, and their definition is somewhat arbitrary. The criteria for grouping was based on latitude and physiographic similarity within the groups. However, they can be used to show the trends in vegetation features at the landscape level as the distance covered by the field sampling was 225 km. Eleven geographic areas were defined (Figure 7), as follows: Table 3. Grouping of the map areas (flight lines) by geographic area in the Arrow Lakes Reservoir. No. Geographic Area Included Flight Lines 1 Deer Park - Renata 1, 2 2 Fauquier 3, 4, 5, 6, 7, 8 3 Burton 9, 10, 11 4 Narrows 12, 13, 14, 15, 16, 17, 18, 19 5 Nakusp - Fosthall 20, 21, 22 6 Halfway River 23 7 Galena Bay 24, 25 8 Beaton 26, 27 9 South Reach 28, 29, 30, Middle Reach 32, 33, 34, 35, 36, 37, 38, 39, 40, Illecillewaet 42, 43, 44 These groupings are tentative and are based on geographic location. The reason for the Halfway River group having only one map area is its physiography: is different from all other sites. It is a sloping, boulder-dominated river channel vegetated with willows and cottonwood, whereas all other groups usually have some sand or silt sand flat areas. Delphinium Holdings Inc. 18

33 Figure 7. Location of and approximate breaks between geographic areas. Delphinium Holdings Inc. 19

34 General parameters and graphs General relationships among average cover, average median heights of the vegetation or species richness, and the main physical variables were explored with a series of graphs. Means of the dependent and independent variables for each community types and geographic areas were summarized in tables. Additional physical variables will be added to the database in future years for further assessment. Multiple regression models To understand which physical variables seem to influence the characteristics of the vegetation in the plots surveyed is of interest in the present study, especially in the context of monitoring changes in vegetation over time. As our main intention was to model (or describe) the vegetation structure of the reservoir, yet not to build precise predictive empirical-based models, multiple regressions were judged an adequate tool (Legendre and Legendre 1998). Therefore, three multiple regression models were built to evaluate the influence of physical variables on, respectively, the variations in cover, median height and species richness of the plots. The physical variables were first standardized to ensure that they would be in the same scale and dimensionless. Then the standard regression coefficients were used to indicate which variable contributed the most to the estimated values of cover, median height or species richness (Legendre and Legendre 1998). The value of the coefficient of determination (R 2 ) indicates the proportion of variation of the dependent variable explained by the variables included in the regression. The probabilities associated which each model (p-values) indicate if the models are significant. As the models were tested by permutations, a p-value of, for example, means that there is less than 0.1% of chances that the model would be obtain by chance only; in other words, that there is a relationship between the variables that is not due to chance. The models were done with a multiple regression computer program developed by Legendre (1999) and parameters of the models were tested with 9999 permutations. Tests done to ascertain the power of permutation tests showed that, for data with non-normal error structure (most likely to be the case with ecological data), the permutation tests have greater power than the normal-theory tests (Legendre and Legendre 1998) in the detection of small differences or effects. Comparison of Arrow Lakes and Revelstoke Reach areas Average cover, average median height and average richness were compared between the Arrow Lakes and Revelstoke areas. Unbalanced non-parametric one-way Analyses of Variances (ANOVA) were performed to verify if the differences in means were statistically significant between the two areas. To complement the description of the difference between the areas, a Chi-square test was also done to assess if the frequencies of occurrence of polygons of the different community types were statistically different between the two regions Monte-Carlo simulations were carried out to test the significance of the Chi-square statistic. Both the ANOVAs and the Chi-square test were performed with the R language (version 2.6.0). Cluster analysis Finally, to assess if the species composition varied among plots along the reservoir, a cluster analysis was performed. Clustering of plots is one of the methods that can be used to describe the patterns in vegetation in the reservoir (Enns 2007a). The results of the clustering were compared to the community types previously defined with the map data. Delphinium Holdings Inc. 20

35 The plots were grouped according to the presence/absence of species. The presence/absence matrix was first transformed into a distance matrix computed with a binary index. The binary index is the inverse of the Jaccard index, and therefore excludes the double-zeros from its computation. It is important to use index that excludes double-zeros when working with presence/absence data, as the absence of a species from two sites does not mean that these two sites are similar (Legendre and Legendre 1998). It is therefore preferable to avoid drawing ecological conclusions from the absence of a species at two sites. For this data analysis, K-Means partitioning was utilized to perform the clustering. K-Means partitioning minimizes the within-group differences and produces a partition of the plots in a number of groups determined by the user (Legendre and Legendre 1998). Generally, one will try to maximize Calinski- Harabasz (C-H) index, as suggested by Milligan and Cooper (1985), as a way to produce the most parsimonious and valid set of groups. The K-Means partitioning was performed with starts to avoid the local minimum problem of the algorithms (Legendre and Legendre 1998). An ordination method was then used to compress the data into a reduced number of dimensions and allow the projection of the plots into a two-dimensional space without too much loss of significant information. Each plot then received a code according to the K-Means group to which it belonged, so that the groups would be detected on the ordination diagram. As presence/absence data were used, the ordination method performed was Principal Coordinate Analysis (PCoA). Indeed, PCoA allows the Euclidian representation of a set of objects whose relationships were measured by a distance index. The axes of a PCoA do not stand for any precise variable, as the matrix used in the computation is a distance matrix and not a raw data matrix (Legendre and Legendre 1998). They are rather an expression of the Euclidian distance among objects. Hence, the closer the plots appeared on the diagram, the more similarities they shared in terms of presence/absence of species. The groups formed were described and their links with physical or environmental variables discussed. The partition and the ordination were both done with the R language (Version 2.6.0). 4.9 Wildlife Habitat Assessment A list of wildlife expected to occur in the study area was generated from the literature and species records from the field. For taxonomic classes (amphibians, reptiles, mammals, birds, butterflies and gastropod), the vegetation community types were ranked for habitat capability using classes (high, moderate, low, nil). The capability of each vegetation community type and wildlife taxon was defined in a series of algorithms for each community type taxon combination. This classification was mapped at the1: 5,000 scale. Patterns in the distribution of habitat capability were observed visually and cross referenced with field records for accuracy. A simple summary of the mapped classification was tabularized. This type of mapping is very general and can not be used to predict wildlife occurrence, but rather is a general guide to understanding capability for broad wildlife taxonomic groups at the landscape level Species at Risk Prior to the field work, the most recent BC Conservation Data Centre (2007) species-atrisk data (CDC) were compiled to determine potential wildlife species occurrences within the study area. Species lists were filtered by the two forest districts (Arrow Boundary and Columbia) the study area covers. The habitat requirements and known distribution of each species on the two lists were determined primarily based on the associated CDC, COSEWIC and Identified Wildlife status reports for wildlife and The Illustrated Flora of Delphinium Holdings Inc. 21

36 British Columbia (electronically reproduced on E-Flora at ) for vegetation. As well, the mapped known locations within the study area of sensitive and non-sensitive occurrences were obtained from the CDC s online mapping service and confirmed by the CDC. Additional distribution data based on Regional District were obtained from the Species at Risk and Local Government website. This information, in addition to field observations as to available habitat types, was used to perform a coarse assessment of the potential for the identified species to occur within the study area. Each species was ranked as follows: Yes either known to occur in the study area or known to occur in the general area and may utilize habitat types found in the study area; No not known to occur in the area or the study area does not contain suitable habitat (e.g. alpine); and, Unknown literature search did not provide sufficient distribution or habitat data to determine potential Results Description of the Vegetation Community Types The following landscape level vegetation community types were recognized in the Arrow Lakes Reservoir; BB: Non-vegetated boulders, steep BE: Beach non-to sparsely vegetated sands or gravels BG: Non-vegetated boulders, gentle slope CL: Saskatoon rock or cliff upper elevation CR: Cottonwood riparian IN: Industrial / residential /recreational LO: Blue Wildrye log zone PA: Reed Canary Grass Redtop upland PC: Reed Canary Grass Lenticular Sedge Mesic: midslopes PE: Reed Canary Grass Horsetail middle to lower slope PO: Waterlily Potamogeton open wate RH: Red-top Hare s Foot Clover upland RR: Reed rill RS: Willow Red Osier Dogwood stream entry SS: Non-vegetated Sand and/or gravels, steep WR: Silverberry river Each section below provides a description of the community type, a representative photo and graphs of the distribution, in terms of total area and number of polygons of a given type by geographical area. Each of the 2,510 mapped polygons was assigned a pure or compound ecosystem code (community types) in the GIS. Ecosystem codes are composed of one to three vegetation community types with a decile indicating the percent cover of the individual unit. Ecosystem codes can be broken down as follows: 5PC-3PE-2BE = 50% PC 30% PE 20%BE Delphinium Holdings Inc. 22

37 Figure 8 shows an example a mapped area, in this case Line 43. The legend on the right describes the units mapped for each polygon. Each polygon is numbered and corresponds with the number on the legend. Following Figure 17, a description of each vegetation community type is provided, and its distribution in the study area is described graphically. Figure 8. Example of mapped community types. This map shows the polygons mapped in Line 43 in Revelstoke Reach with the legend indicating the community type, or types, identified for each polygon. Delphinium Holdings Inc. 23

38 5.1.1 RS Willow - Red osier dogwood - Stream entry This vegetation type is associated with very bouldery, open stream entries to the reservoir, with shrubby marginal vegetation. Where the area was previously forested, it often retains some of the original forest vegetation and has a relatively high species richness, compared to other community types. Vegetation was observed to consist of various species of willows, cottonwood, alder, lodgepole pine, white prairie aster, biennial cinquefoil, knapweed, bluejoint, red top, thimbleberry, Canada goldenrod, western witchgrass, quackgrass, species of Juncus, and grey freyed-cap moss, dogpelt lichens, Cladonia lichens and several species of mushrooms. Figure 9. Representative photo of the RS community type. Figure 10 and 11 show that stream entries occur in all map areas in the study area, but are most common (by hectares) in the Middle Reach portion of the study area, followed by Fauquier and the Narrows. Delphinium Holdings Inc. 24

39 Distribution of RS Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 10. Distribution (expressed in total hectares of the type) of the RS community type by geographic area. Distribution of RS Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 11. Distribution (expressed in the total number of polygons in which the type occurred) of the RS community type by geographic area. Delphinium Holdings Inc. 25

40 5.1.2 RR Rush Wet sites/ seepage/rill This vegetation type is always associated with continuous sources of fresh water, i.e. underground streams or seeps entering the reservoir. It is usually topographically depressional. Water may originate from open streams upslope, but may also continuously percolate through surficial materials in the drawdown zone. Materials always have some fine textured and compacted component, usually due to silts, but often silts mixed with sands, and these can be cemented and imbedded with fine to coarse gravels. They usually have dense, but patchy cover of mixed semi-aquatic or riparian species, with barren areas. Species include rushes, reeds and sedges i.e. Juncus, Luzula, Carex, swamp horsetail and occasionally willows. The type is species poor, but distinct. Figure 12. Representative photo of the RR community type. Figure 13 and 14 show that RR also occurs in most map areas in the study area, but is most common (by hectares) in the Narrows and Nakusp Fosthall. RR represents a small portion of the study area. Delphinium Holdings Inc. 26

41 Distribution of RR Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 13. Distribution (expressed in total hectares of the type) of the RR community type by geographic area. Distribution of RR Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 14. Distribution (expressed in the total number of polygons in which the type occurred) of the RR community type by geographic area. Delphinium Holdings Inc. 27

42 5.1.3 PO Waterlily - Potamogeton open water This vegetation type occurs in backwaters, large deep depressional areas, cut-off oxbows or channels and has standing brackish to slow moving water present most of the year. The areas may dry out in very dry successive years. The vegetation is species poor and mainly consists of edge-dwelling and floating semi-emergent plants. Species include floating leaved pondweed, knotweed, Eurasion milfoil, and other emergent plants. Figure 15. Representative photo of the PO community type. Figure 16 and 17 indicate that PO is very uncommon in the study area, covering a very small portion of the map area and being mostly confined to Revelstoke Reach. Delphinium Holdings Inc. 28

43 Distribution of PO Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet 2.62 Figure 16. Distribution (expressed in total hectares of the type) of the PO community type by geographic area. Distribution of PO Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 17 Distribution (expressed in the total number of polygons in which the type occurred) of the PO community type by geographic area. Delphinium Holdings Inc. 29

44 5.1.4 PE Reed Canary Grass - Horsetail middle to lower slope This vegetation type occurs mainly at low to middle elevations and is influenced by the Columbia River in Arrow Lake or Revelstoke Reach. Physical site characteristics differ from RR sites in that water is not continuously supplied from upslope via ground water supplies. PE can be bouldery, but is always relatively compacted and non-aerated. It usually occurs in fine textured silty materials, appears to be susceptible to erosion and weathering. In hummocky terrain, it can have no vegetation on the tops of the hummocks. It is less common throughout the reservoir than PC, usually occurs downslope of PC and is less variable. Species richness is very low, consisting of reed canary grass and lenticular sedge, with common horsetail and willows (usually very small and impacted by water movement). Sitka sedge can occur in Revelstoke Reach map areas, and stork s bill is very common and abundant in this type in the Arrow Lake map areas. Mosses occur occasionally. Figure 18. Representative photo of the PE community type. Figure 19 and 20 indicate that PE is almost always present, except at Deer Park, Beaton and Halfway River. PE is common and abundant throughout the rest of the study area. Delphinium Holdings Inc. 30

45 Distribution of PE Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 19. Distribution (expressed in total hectares of the type) of the PE community type by geographic area. Distribution of PE Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 20 Distribution (expressed in the total number of polygons in which the type occurred) of the PE community type by geographic area. Delphinium Holdings Inc. 31

46 5.1.5 PC Reed Canary Grass - Lenticular Sedge mesic This vegetation type is very common and widespread, occurring in all the map areas of the Arrow Lakes Reservoir. Materials vary somewhat, but usually consist of gently sloping to flat anoxic, compacted silty materials, with some clay and fine to coarse sand. Gravel depositional areas can have openings, which result in a few more species than the usual species composition for this vegetation community type, which is comparatively species poor, especially in Revelstoke Reach. Occasionally, small sinkholes in the surface materials occur; these are likely the result of stumps that have degraded and washed away. The PC type covers large parts of individual polygons and is dominated by reed canary grass, which can form very dense, pure stands of one hectare or larger in size, especially in Revelstoke Reach. Other species include lenticular sedge and common horsetail, with tumble mustard, and mosses also occurring. Small bedstraw, monkey-flower, common mint, wood forget-me-not and dandylions are also common. Several species of Carex other than C.lenticularis can be present. This type has been heavily grazed by geese in the Arrow Lakes, and in this condition, it can be invaded by several species of sedges, grasses, cranesbill, bedstraw, and other inundation-tolerant or requiring plants. Figure 21. Representative photo of the PC community type. Figure 22 and 23 indicate that PC is the most common and abundant vegetation type in the study area, but is most common and takes up the largest portions of map areas in Revelstoke Reach. Delphinium Holdings Inc. 32

47 Distribution of PC Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 22. Distribution (expressed in total hectares of the type) of the PC community type by geographic area. Distribution of PC Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 23. Distribution (expressed in the total number of polygons in which the type occurred) of the PC community type by geographic area. Delphinium Holdings Inc. 33

48 5.1.6 PA Reed Canary Grass - Redtop dry upland shedding sites This vegetation type seems to be associated with raised, well drained microtopography and can occur at a range of elevations. It is relatively frequent, but often too small to map, and occurs on sloped or on well drained, sandy gravelly materials. This type is usually somewhat variable, but displays a relatively high species richness compared to PC or PE. While this type is often dominated by reed canary grass, the species composition always includes at least a few species of agronomic and native grasses, including redtop, creeping bentgrass, blue wildrye, Canada bluegrass, Kentucky bluegrass, and others. Various pasture and ditch weeds, such as sourweed, chicory, oxe-eye daisy also occur, in addition to somewhat dry forest-type mosses, such as redstemmed feather moss, and palm-tree moss. Figure 24. Representative photo of the PA community type. Figure 25 and 26 indicate that PA is very common and widespread, but small in area, as noted above. Delphinium Holdings Inc. 34

49 Distribution of PA Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 25. Distribution (expressed in total hectares of the type) of the PA community type by geographic area. Distribution of PA Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 26 Distribution (expressed in the total number of polygons in which the type occurred) of the PA community type by geographic area. Delphinium Holdings Inc. 35

50 5.1.7 LO Blue wild rye - log zone This vegetation type is limited in elevation to the highest zone, near the 440 meter level, and consists of foreshore driftwood, logs and very sparse, grassy, weedy vegetation that is tolerant of shifting driftwood. It can be depressional, as a result of scouring. This type is often mapped as a thin linear polygon, but occasionally occurs on gentle slopes and can be greater than 200 meters wide. Bare mineral soils, which are mostly coarse sands, are very common, and large areas can be barren from scouring effects. There is usually a mixture of fine-textured woody debris that acts as a mulch to trap seeds and protect plants. Species composition of the LO type is a mix of weeds and remnants of the previous (pre-inundation) vegetation type, as well as inundation tolerant species, including low covers of willows, orchard grass, cheatgrass, hoary allysum, knapweed, and great mullein. Figure 27. Representative photo of the LO community type. Figure 28 and 29 indicate that LO is common and widespread, and occurs most frequently in the Narrows portion of the study area. It is not common in Revelstoke Reach, as sources of logs probably are not common in the Reach. Delphinium Holdings Inc. 36

51 Distribution of LO Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 28. Distribution (expressed in total hectares of the type) of the LO community type by geographic area. Distribution of LO Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 29. Distribution (expressed in the total number of polygons in which the type occurred) of the LO community type by geographic area. Delphinium Holdings Inc. 37

52 5.1.8 RH Red-top Hare s foot clover upland This vegetation type is very similar to the LO vegetation type, but has no logs or accumulated debris, and is often convex, rounded and well drained. Similar to LO, the RH has been impacted by wave scouring, but not by debris movement. It is restricted to the higher elevation wave zone. Soil textures range from clays to sands. Remnants of the original forested soils and plant species compositions occur. Patches of vegetation can be absent, but in general the RH vegetation type has a higher species richness than LO. Species include several trees as seedlings (few juveniles survive), including Douglas-fir, western hemlock, western red cedar, western white pine, black locust, trembling aspen, grand fir, mountain ash and Douglas juniper. Shrubs are also common and include prickly rose, Nootka rose, alder. Grasses are often dense and include redtop, timothy, june grass, poverty oatgrass and bluebunch wheatgrass. Hare s foot clover is very common in RH in the Arrow Lakes portion of the reservoir. Weedy species occur, but are not as common as in the LO type. Hawkweeds, Dalmation toadflax, oxeye daisy, dandelion, and several species of mosses, lichens, and liverworts occur. This vegetation type has the highest species richness occurring in a single plot in the vegetation data. Figure 30. Representative photo of the RH community type. Figure 31 and 32 indicate that RH is most common in the Narrow, but it occurs throughout the study area, covering small, but distinct upper elevation portions of the map area. Delphinium Holdings Inc. 38

53 Distribution of RH Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 31. Distribution (expressed in total hectares of the type) of the RH community type by geographic area. Distribution of RH Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 32 Distribution (expressed in the total number of polygons in which the type occurred) of the RH community type by geographic area. Delphinium Holdings Inc. 39

54 5.1.9 CR Cottonwood riparian This vegetation type is stable in the sense that it is seldom inundated for long periods of time each year and may not be flooded for several years in a row, as evidenced by the presence of some of the most flood intolerant species in the study area. It consists of remnants of original forested soils and vegetation at the upper boundary of the drawdown zone. This vegetation type mostly occurs above the 440 meter elevation, but it also occurs at and below the 440 meter elevation band (field data show that elevation of CR-type plots range from 437 to 440m). The CR vegetation type is often dominated by black cottonwood and balsam poplar, with trembling aspen and occasionally very large specimens of Western red cedar, Douglas-fir, and Western white pine. No other vegetation type has as much variation in plant heights as the CR type. Ponderosa pine occurs at the southern end of the Arrow Lakes portion of the reservoir, and lodgepole pine occurs at the northern end. Western hemlock and Western red cedar occur in the Beaton Arm. There are highly variable assemblages of non-vascular and vascular plants in the CR vegetation type, including horticultural species. A range of forested vegetation from wet to very dry forest types occurs, including falsebox, Oregon-grape, pinegrass, trailing bramble, bedstraw, peavine, and various mosses, lichens and liverworts. This type may be an important seed source for lower elevation sites. Figure 33. Representative photo of the CR community type. Figure 34 and 35 show that CR is common in occurrence, but very small in area across the mapped sites. The largest areas occur at the Narrows and in the Middle Reach. Delphinium Holdings Inc. 40

55 Distribution of CR Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 34. Distribution (expressed in total hectares of the type) of the CR community type by geographic area. Distribution of CR Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 35. Distribution (expressed in the total number of polygons in which the type occurred) of the CR community type by geographic area. Delphinium Holdings Inc. 41

56 CL Saskatoon - rock or cliff upper elevation This vegetation type occurs on rocky, upper elevation margins of the map areas, occasionally consisting of cliff faces, or rock outcrops and rock cutaways. Bouldery fans and small debris torrents on steep slopes are often large enough to be mapped within a polygon. This vegetation type is occasionally on unstable materials, and can be subjected to very strong wave action. This vegetation type usually has a very sparse cover of drought tolerant trees, shrubs and grasses and crustose lichens. It often occurs above the LO vegetation type, and below roads. Some remnants of original forested vegetation may be present. Figure 36. Representative photo of the CL community type. Figure 37 and 38 show that CL is absent from most of the study area, but does occur in the map areas of Fauquier, Narrows, and the South and Middle portions of Revelstoke Reach. Delphinium Holdings Inc. 42

57 Distribution of CL Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 37. Distribution (expressed in total hectares of the type) of the CL community type by geographic area. Distribution of CL Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 38. Distribution (expressed in the total number of polygons in which the type occurred) of the CL community type by geographic area. Delphinium Holdings Inc. 43

58 IN Industrial / Residential/ Recreational This vegetation type occurs across all elevation bands in the m range of the drawdown zone. It is characterized by heavily disturbed soils and vegetation due to roads and a variety of land uses, including past settlement. Soils are variable, but are always compacted, and have weedy margins. This vegetation type is probably a major source of weed invasion into other vegetation types in the reservoir. It is dominated by a mix of drought and/or inundation tolerant opportunistic native and weedy vegetation, such as sourweed spp., red and white clover, sweet clover, knapweed spp., cheatgrass, mullein and others. Figure 39. Representative photo of the IN community type. Figure 40 and 41 show that IN is very common in the southern portion of the Arrow Lakes study area and the Middle Reach of Revelstoke Reach, but otherwise not common north of Nakusp. Delphinium Holdings Inc. 44

59 Distribution of IN Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet 2.30 Figure 40. Distribution (expressed in total hectares of the type) of the IN community type by geographic area. Distribution of IN Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 41. Distribution (expressed in the total number of polygons in which the type occurred) of the IN community type by geographic area. Delphinium Holdings Inc. 45

60 WR Silverberry river This vegetation type occurs only on large rivers or permanent large streams entering into the reservoir. It consists of washed boulders and gravels with sand deposition in between boulders. Slopes are very gentle to flat, and can be undulating due to river action. This type is usually a straight to serpentine large fresh water river bed, in which a river enters the reservoir at right angles. The WR type is always influenced by fast moving water at high volumes during spring, winter and fall freshet, and can be very dry and hot during the summer period. Gravel bar willows and other shrubs, such as wolf willow and silverberry, may be the only vegetation to occur. The WR vegetation type differs from the gentler stream entry (RS) type, which is characterized by a much lower volume of water entering at slower speeds. Also, WR materials are mainly very coarse, compared to the fine-textured and organic materials that may occur in the stream entries. Figure 42. Representative photo of the WR community type. Figure 43 and 44 show that WR is relatively uncommon, but can form very large polygons where it does occur (e.g. the Narrows). Delphinium Holdings Inc. 46

61 Distribution of WR Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 43. Distribution (expressed in total hectares of the type) of the WR community type by geographic area. Distribution of WR Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 44. Distribution (expressed in the total number of polygons in which the type occurred) of the WR community type by geographic area. Delphinium Holdings Inc. 47

62 BB Non-vegetated boulders, steep This vegetation type occurs on steep to very steep, boulders or heavy gravels. Vegetation is usually very sparse or absent, but may consist of willows and reed canary grass when it occurs. Figure 45. Representative photo of the BB community type. Figure 46 and 47 show that BB is very common in occurrence across the study area, but covers only a very small proportion in terms of hectares. It is most common in the Narrows, Galena Bay (BB makes up most of Galena Bay), and the South Reach portions of the study area. Delphinium Holdings Inc. 48

63 Distribution of BB Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 46. Distribution (expressed in total hectares of the type) of the BB community type by geographic area. Distribution of BB Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 47. Distribution (expressed in the total number of polygons in which the type occurred) of the BB community type by geographic area. Delphinium Holdings Inc. 49

64 BG Sparsely-vegetated boulder flats This vegetation type is typically an alluvial or fluvial outwash plain, consisting of boulders of various sizes, located always on gentle to flat the reservoir (i.e. no creeks or seepage provide water in the hot period of exposure in spring, summer or fall). Due to washing of fine materials over the surfaces, grit can collect between boulders, and some very drought and inundation tolerant plants occur, including as willows, horsetail, reed canary grass, sourweed, and red top. Vegetation is almost always very sparse or absent. Figure 48. Representative photo of the BG community type. Figure 49 and 50 show that BG is most common toward the southern portion of the study area, and makes up small individual areas in the remainder of the study area. BG is absent from Burton and Illecillewaet. Delphinium Holdings Inc. 50

65 Distribution of BG Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 49. Distribution (expressed in total hectares of the type) of the BG community type by geographic area. Distribution of BG Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 50. Distribution (expressed in the total number of polygons in which the type occurred) of the BG community type by geographic area. Delphinium Holdings Inc. 51

66 SS Non-vegetated Sand and/or gravels, steep With the exception of the Narrows, this vegetation type is not common, occurring only in small areas throughout the reservoir. It consists of sandy banks, often very steep with failing slopes. Stepped patterns occur that correspond to the typical full pool events in the reservoir. This type consists of only a few species of plants, including reed canary grass and common horsetail. Figure 51. Representative photo of the SS community type. Figure 52 and 53 show that SS occurs in a few polygons in each map area, with the highest occurrence (in hectares) in the Narrows and the Middle Reach portion of the reservoir. Delphinium Holdings Inc. 52

67 Distribution of SS Community Type Hectares Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 52. Distribution (expressed in total hectares of the type) of the SS community type by geographic area. Distribution of SS Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 53. Distribution (expressed in the total number of polygons in which the type occurred) of the SS community type by geographic area. Delphinium Holdings Inc. 53

68 BE Beach Non-vegetated flat sands This vegetation type consists of flat to gently undulating, fine-textured sands with a mixed silt content. It usually occurs at very low to mid elevation, and appears to be scoured by water currents. The two plots of BE type sampled on the field were at 434 and 435m. Dust plumes originate from this type. This vegetation type is often very sparsely vegetated to non-vegetated and is occasionally imbedded with gravels. Reeds and rushes occasionally occur. Reed canary grass and lenticular sedge are not common, but if silts, clays and some imbedded gravels occur, they can form small island -like colonies that are often somewhat mobile on the surface. Figure 54. Representative photo of the BE community type. Figure 55 and 56 show that BE is common in the Narrows and Fauquier. This type may be over represented in the mapping due to the time of year of the photography. Delphinium Holdings Inc. 54

69 Distribution of BE Community Type Hectares Deer Park - Renata Fauquier Burton 7.02 Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 55. Distribution (expressed in total hectares of the type) of the BE community type by geographic area. Distribution of BE Community Type Number of Polygons Deer Park - Renata Fauquier Burton Narrows Nakusp - Fosthall Halfway River Galena Bay Beaton South Reach Middle Reach Illecillewaet Figure 56. Distribution (expressed in the total number of polygons in which the type occurred) of the BE community type by geographic area. Delphinium Holdings Inc. 55

70 Distribution of the Community Types The following section provides a summary of the distribution of the community types throughout the study area. A total of 2,510 polygons were mapped across an area of 2, hectares. Table 4 summarizes the total number of hectares of each community type and the number of polygons which the community type was mapped in. Table 4. Summary of the areas of each of the sixteen vegetation types mapped in the Arrow Lakes Reservoir. The summary shows the total area (in hectares) of each community type as well as the number of polygons in which the type occurred. Type Hectares # of Polygons BB BE BG CL CR IN LO PA PC PE PO RH RR RS SS WR TOTAL 2, ,631 Delphinium Holdings Inc. 56

71 5.2 Description of the Vegetation with the Field Data The analysis of the field data showed that the vegetation of the Arrow Lakes Reservoir is remarkably uniform from the southern map areas near Castlegar to the northern areas of the Revelstoke Reach. With few exceptions, most sites are dominated by Reed Canary Grass (Phalaris arundacea) and Lenticular Sedge (Carex lenticularis), with common horsetail (Equisetum arvense) and various weedy and/or inundation tolerant species occurring depending on the materials, the elevation, the degree of shelter from scouring effects and other disturbance. There are subtle patterns in the vegetation that appear to be related to elevation, moisture regime or moisture availability and materials type. There appear to be superficial resemblances to associations defined by MacKenzie and Moran (2004), in particular the flood associations, but the hydrological regimes and species compositions are not similar. Future analysis will examine the relationship between the dependant variables (species richness, cover, height) and physical variables, such as water supply, terrain texture, etc. (Enns 2007a). A total of 171 field plots were surveyed from the September 13 to October 15, The distribution of plots in the map areas is shown in Figure 57. A total of 188 species (or taxa identified to genera) were observed in the field (see Appendix 1). Some taxa could not be identified to species due to phenology of the plants at the time of sampling (fall), or poor condition. Many specimens of uncertain lineage bore mixed characteristics due to the physiological constraints of repeated long term inundation (Kozlowski 1997). Some species have been sent to a taxonomist for verification / identification. Almost all species found in the survey can be described as opportunistic species or weeds, which are tolerant of extremes in moisture and drought or have semi-emergent to emergent growth habits. Some are remnants of previous forest or agricultural land uses. Most of the species found in the surveys were rare occurrences, appearing only once (88 species) or twice (29) in the whole survey. Eight species were present in more than 20 plots, among which reed canary grass (148 occurrences), common horsetail (109 occurrences) and Carex species (156 occurrences, mainly by Carex lenticularis, with 93) were clearly the most frequent species encountered in the surveyed areas. Delphinium Holdings Inc. 57

72 Figure 57. Distribution of the sample plots in the the Arrow Lakes Reservoir Delphinium Holdings Inc. 58

73 5.2.1 Distribution of variables The average cover of vegetation varied greatly among plots (Table 5). Many plots had openings with bare mineral soil or exposed materials. Few were considered totally covered by vegetation and of those, reed canary grass was the only monospecific, high cover species to occur. On average, 16% of the area of the plots was covered by vegetation, indicating that bare soil was common in all plots to some extent. In general, the vegetation was small in stature, varying between 12 cm and 35 cm on average (Table 5). Maximum height was typically achieved by tree or shrub species (such as willows, cottonwood, pine spp.) and at times, by reed canary grass or sedges. Six species or taxa were encountered in each plot, on average (Table 5). Few plots were barren, and some plots had as many as 30 species. However, most of the plots have between three and ten of any of the 188 species encountered in the reservoir. Table 5. Summary of the descriptive parameters of the dependent variables in the plots. Variable Mean Standard deviation Minimum Maximum Cover (%) Minimum Height (m) Maximum Height (m) Median height (m) Richness Elevations of the centre points of the plots ranged between 432m and 442m and the slope of the plots was typically gentle (6 degrees on average), although slopes were occasionally steep (Table 6). Results for aspect of plots were not summarized as aspect is only a descriptive variable unique to each plot. Table 6 Summary of descriptive parameters of the independent variables. Variable Mean Standard deviation Minimum Maximum Elevation (m) Slope (degrees) The plots sampled in the field were not evenly distributed among the community types that were defined based on the aerial pictures analysis. The types BB, LO and RS were sampled only once among the 173 plots, while 97 plots were of PC types (Table 7). Richness. median height and cover also varied greatly among community types. Type CR was the richest, while type PA was the tallest and type BB presented the highest average percentage of cover (Table 7). Delphinium Holdings Inc. 59

74 Table 7. Summary of the characteristics of each community type represented by the plots surveyed in the field. Community types Number of plots AV elevation (m) AV Slope (degrees) AV Richness AV Median Height (m) AV Cover (%) BB BE CR IN LO PA PC PE PO RH RR RS SS Table 8 shows the average number of plots in each map area, the average easting and northing, the average elevation, slope, and species richness, median height and cover of each geographic area as summarized in the 2007 field data. Table 8. Summary of the characteristics of each geographic area represented by the plots surveyed in the field. Areas Number of plots Easting Northing AV Elevation (m) AV Slope (degrees) AV Richness AV Median Height (m) AV Cover (%) Beaton Burton Deer Park-Renata Fauquier Galena Bay Halfway River Illecillewaet Middle Reach Nakusp - Fosthall Narrows South Reach Richness varies among geographic areas, but the greatest species richness occurs at Halfway River and at Nakusp Fostall. Both these areas have bouldery river entrances with a high diversity of riparian species. Illecillewaet and the Narrows are also relatively species rich, likely due to raised sand ridges and topographic diversity at both map areas. It should be noted, however, that the number of plots is not equal between geographic areas, which are grouped because of similar geographic location and physiography. For example, Galena Bay is in a group of its own because it is isolated and consists almost completely of boulders which is different from other sites. Despite having a large number of plots, Deer Park and Renata are not as species rich as the middle section of the Arrow Lakes portion of the reservoir, and in the South Reach, due to the dominance of reed canary grass, species richness is very low in this map Delphinium Holdings Inc. 60

75 area. Median height and cover also vary among geographic areas (Table 8). Illecillewaet area presents the tallest vegetation and the highest average cover of all the geographic areas Variation in vegetation cover Relationships between vegetation cover and the independent variables estimated in the field for all the plots were explored graphically. No relationships were obvious when cover was plotted against the slope or the aspect of the plots. However, a weak relationship was detected between plant cover and elevation (Figure 58) Average vegetation cover according to the elevation of the plots Average vegetation cover (%) Elevation (m) Figure 58 Variations in Vegetation Cover (%) according to the elevation of the plots. Elevations between 434m and 440m were kept for that analysis. To further examine the possible relationships among cover and the three independent variables, a multiple regression model was built (R 2 =0.076; p=0.013). A total of 163 of the 171 plots were used for the model, after eliminating plots with missing data. The equation of the regression is: Y= -1.32* elevation 0.45 * slope * aspect Although the percentage of variation in cover explained by the model is small (7.6%), the model is significant. The graph suggests that elevation and slope had a slight negative effect on vegetation cover. The higher standard regression coefficient for elevation indicates that this variable contributes to most of the variation of vegetation cover explained by the model. This suggests that at the highest elevation, especially on steeper slopes, less vegetation cover should be encountered. This is likely due to scouring at the high elevation mark. Examples of this observation are shown in Figure 59 below. Delphinium Holdings Inc. 61

76 Figure 59. Four examples of scouring at the 440 to m elevation contributing to lower cover at higher elevation Variations in vegetation height Average median heights of vegetation for each plot were used to examine the relationships between vegetation heights and the three independent variables. Plots situated between 434m and 440m were included. No relationships were detected between average median heights and slope or aspect, possibly because of a lack of differences in slope. The monitoring plots are largely flat and with flat sites, aspect is not as important in vegetation development. However, a positive relationship between average median height and elevation was observed, as presented in Figure 60 (below). Delphinium Holdings Inc. 62

77 1.4 Average Median Height of vegetation according to elevation of the plots 1.2 Average Median Height (m) Elevation (m) Figure 60. Variations in average median heights (m) and elevation of the plots (m). The multiple regression model built between average median heights and the three explanatory variables explained 28% of the variations in height (p=0.0001). Its equation is: Y= 0.56 * elevation 0.006* slope 0.046* aspect The high standard regression coefficient of elevation suggests that elevation is important in the development of the height of vegetation, compared to the other variables considered. Hence, the vegetation tends to be taller when the plots are situated at a high elevation, likely because shrubs and trees grow at the top of the slopes. This is shown in Figures 61 and 62. Delphinium Holdings Inc. 63

78 Figure 61. Average median heights (m) are greater at highest elevation and variation is highest due to shrub growth at the highest elevation sites. Figure 62. Average median heights (m) are declining with decreasing elevation. Delphinium Holdings Inc. 64

79 5.2.4 Variations in species richness Relationships were also examined between the species richness of the plots and their elevation, slope and aspect. Positive relationships were suggested among each of the three independent variables. Figure 63 shows an example, with richness plotted against slope of the plots. Future examination will include other independent variables, such as terrain stability, soil texture, water availability, etc. 35 Species richness according to the slope of the plots Richness Slope (degrees) Figure 63. Variations in richness (number of species) according to the slope of the plots (between an elevation of 434m and 440m). Figure 63 indicates that at relatively gentle slopes, species richness increases, but when slopes are over-steepened, numerous plants are not able to gain a foothold on the slope. A positive influence of the three variables of slope aspect and elevation was detected by the multiple regression model. The three variables (slope, aspect and elevation) explained 16% of the variations of richness (p=0.0001). The equation is presented below: Y= 0.07* elevation * slope * aspect This suggests that number of species increases in plots that have a higher elevation and a steeper slope. There is a tendency for steep slopes to occur at the to 440 meter elevation with better drainage and a higher number of species. Overall, even though the percent of variation explained by the multiple regression models is rather small, the models still suggest that the vegetation is sparser (i.e. lower cover), but taller and richer in plots at high elevation. Therefore steep slopes and aspects of plots augment the richness of the plots by providing better drainage, but scouring and drought-prone sandy soils at the higher elevations also appear to diminish the total cover of vegetation. Delphinium Holdings Inc. 65

80 5.2.5 Differences between Areas in the Arrow Lake vs Revelstoke Reach A comparison between the differences in vegetation cover, average median vegetation height and species richness was made between the Arrow Lake and Revelstoke Reach (Areas A and R). Table 9 summarizes the variations in cover, median height and richness between the two areas. Table 9. Summary of the variations of the vegetation cover, vegetation median height and richness between areas A (Arrow Lake) and R (Revelstoke Reach). Areas Variables Mean Standard Confidence Deviation Interval Minimum Maximum Cover [0, 30.6] 0 45 A Median Height [0, 0.45] Richness 7 6 [0, 19] 0 30 Cover [0, 51] R Median Height [0, 0.78] Richness 6 3 [0.12,12] 1 18 Table 9 indicates that vegetation cover and median height are almost double between the Arrow and the Revelstoke Reach areas, with covers and heights being much higher in Revelstoke Reach than in Arrow Lakes. The vegetation of the Reach is more heavily dominated by reed canary grass, which forms almost pure stands. In the Arrow Lakes portion of the study area, the vegetation is sparser, but tends to be richer in species, although this difference is not significant (see below). One-way ANOVAs were performed to assess if the differences observed in cover, median height and richness were statistically significant between the two areas. As suggested by the table, the average richness was not statistically significant between area A and R (F=2.63; p=0.11). However, both the difference in average vegetation cover (F=18.55; p=0.0001) and average median height (F=25.96; p=0.0001) between the two areas were statistically significant. Hence, it suggests that vegetation cover was higher and plants were taller in the Revelstoke Reach. The frequencies of occurrence of polygons by community type were also statistically different between the two areas (Χ 2 =455, p=0.0005). As the total number of polygons defined were different for the two areas (3232 units in total in Arrow Lakes and 1400 units in Revelstoke), the frequencies of occurrence for each community types in Arrow Lakes were corrected. Each frequency was therefore multiplied by 1400 and divided by 3232, so that the two sums of rows would be equal, and a Chi-square test could be performed. The results of this test suggest that not only are the total frequencies of community types different between the two areas, but also, the proportion of certain community types vary between the areas. In other words, for example, the PC types occur, in proportion, twice as frequently in the Revelstoke Reach area than in the Arrow Lakes, and BE type occurs three times more often in Arrow Lakes than in Revelstoke Reach. Figure 64 shows the proportions of polygons for each community types in the two areas. Delphinium Holdings Inc. 66

81 Proportions* Proportions of map units for each community types for Arrow Lakes and Revelstoke BB BE BG CL CR IN LO PA PC PE PO RH RR RS SS WR Arrow Lakes Revelstoke Figure 64. Proportions of the map units for each community type for Arrow Lakes and Revelstoke areas. * Frequencies shown for Arrow Lakes were corrected for the higher total number of map units sampled (i.e. the total frequencies of map units are equal for the two areas (1400) in this graph) Description of Vegetation Patterns Vegetation patterns were assessed through cluster analysis. This analysis aimed at grouping the plots according to the presence/absence of species and taxa in order to detect general patterns. To perform the analysis, the 46 species that occurred in at least five plots or more were selected and then submitted to a K-Means partitioning. Seven groups of plots were produced (Calinski-Harabasz criteria = 48.7) and then superposed on a PCoA. Figure 16 illustrates the result of the ordination with the seven groups of sites. The characteristics of each group are summarized in Table 10 and the species composition in Table 11. The species with very low frequency of occurrence are usually removed from a statistical data set to allow for analysis. Revelstoke Reach had much higher numbers of low frequency or single occurrences of wetland species, from genera such as Carex, Luzula, Scirpus, etc., whereas Arrow Lakes has a range of drier, more terrestrial species occurring in the field data. This difference may be a function of the steeper slopes, drier sands, presence of large bouldery fans, and possibly faster moving water in the Narrows and other portions of the Arrow Lake section of the reservoir. Figure 65 indicates that the two first axes of the ordination explain 35% of the variation in presence/absence of species or taxa among the plots. The seven groups are well delineated in the reduced space. The average richness, slope and aspect vary among the groups (Table 10). Delphinium Holdings Inc. 67

82 Figure 65. Projection in the two first axes of the ordination PCoA (19.5% and 15.5% of the variation explained, respectively) of the groups formed by K-Means partitioning. Table 10. Characteristics of the seven groups defined by the K-Means analysis. AV stands for average. groups Number of plots AV richness Elevation (Av, min-max) Slope (Av, min-max) ( ) 6.8 (1-22) ( ) 8.1 (1-30) ( ) 3 (0-16) ( ) 4.4 (0-23) ( ) 5.1 (1-15) ( ) 14 (1-36) ( ) 7.7 (1-20) Delphinium Holdings Inc. 68