Nearshore Habitats Why What You do Matters. Landscapes on the Edge November 2016

Transcription

1 Nearshore Habitats Why What You do Matters Landscapes on the Edge November 2016

2 Primary Topics Focus on marine shorelines ESA species rely on this area Many other fish and wildlife rely on this area The nearshore is a narrow productive ribbon Nearshore health is dependent upland conditions Humans have options for how they manage their lands & landscapes 2

3 Nearshore Ecosystem Riparian Forest Bluffs Estuary Beach Eelgrass Kelp 3

4 Puget Sound and its Watershed 16, 000 square miles land 10,000 streams and rivers 2,500 miles of shoreline * all figures for WA state alone * 4

5 Puget Sound Nearshore Ecosystem Semi-Enclosed Coastal Sea Steep coastline with narrow nearshore zone Mixed sand/gravel beaches Strong regional gradients Tides-Twice a day Ecology strongly linked to geology and physical processes Rich biological resources 5

6 Puget Sound Chesapeake Bay Curtesy of Hugh Shipman 6

7 Puget Sound Supports 100 s of spp. of wildlife Over 200 spp. of fishes 100 s of spp. of aquatic invertebrates 10+ spp. of marine mammals 7 Photo: Jen Vanderhoof

8 Grunt Sculpin Speckled Sanddab Photo: Jen Vanderhoof Spiny Lumpsucker Ratfish Photo: Jen Vanderhoof Photo: Jen Vanderhoof Gunnels Photo: Jen Vanderhoof 8

9 Wildlife Photo: Robyn Ricks Photo: Jen Vanderhoof Photo: Robyn Ricks 9

10 10 From Phill Dionne

11 11

12 What size gravel do they spawn in? Surf Smelt Sand Lance 12 Adapted from Phill Dionne

13 Forage Fish Map Spawning Surf smelt Sand lance being foraged 13

14 Eelgrass 14

15 Kelp Add kelp pictures 15

16 PACIFIC SALMON ARE MARINE FISHES Photo by Hans Berge Pink Coho Chinook Photo by Vali Eberhardt cutthroat Steelhead Photos by Phil Simpson Photo by Geoff Clayton Photo by Rodney Hsu Chum Sockeye 16 Photo by Hans Berge

17 NEARSHORE 17

18 General Functions of Shallow Nearshore Habitats for Juvenile Salmon Feeding Migration Refuge from predators Physiological transition from freshwater to saltwater 18

19 Diet 19

20 Overall diet composition based on prey ecology for juvenile Puget Sound Chinook 100% 90% 2001 n= empty mm mean n empty mm mean Leaf Hopper 80% 70% % Composition 60% 50% 40% 30% 20% Crab Larvae 10% 0% Numerical Gravimetric Numerical Gravimetric terrestrial riparian supralittoral/marsh marine planktonic/neritic plant matter marine benthic/epibenthic other Polychaete 20

21 Switching Gears 21

22 Human Influences Armoring Filling Dredging Pollution Overwater Structures Clearing and Grading Non-native species 22

23 Currently, King County has less than 2% of its historic estuarine wetlands left Adapted from Collins and Sheikh 2005 KVI or Point Heyer, Vashon Island, 23 photo from WADOE

24 Historic Elliot Bay Shoreline 24

25 Filling Loss of shallow water habitat Loss of riparian functions Changes in hydrology Elimination of spawning, rearing and refuge habitat 25

26 Disruption of littoral drift/hydrology Alters juvenile salmon migration patterns Overwater Structures Reduced primary productivity (shade) Loss of intertidal/subtidal habitat Introduction of contaminants 26

27 Seattle Post-Intelligencer 27

28 Shoreline Armoring: What is it? Working definition man-made structures constructed along the shorelines to reduce shoreline erosion Typically called: Bulkheads, Revetments, Sea walls Typically made of: Rock or Rip-Rap, Cement, Sheet Pile, Creosote Logs, ecology blocks, & broken concrete Less typical old tires, box springs, car bodies) 28

29 Shoreline Armoring in the Green-Duwamish Watershed 92 miles of marine shoreline Total=63% is armored Mainland is 80% armored Islands are 50% armored 29

30 Impacts of Shoreline Armoring Beach erosion Impounds sediments Interrupts littoral drift Change in sediments sizes Change in invertebrate spp.composition Loss or change in submerged aquatic veg Loss of riparian vegetation Loss of woody debris Reduces shallow water habitat Loss of forage fish spawning habitat 30

31 Miles Wood Distribution Along WRIA Marine 9's Shorelines Marine ofshorelines King County 64% 64% 15% 15% 21% 21% None LWD DRIFT Unarmored-LWD Unarmored-Drift logs SW Vashon Island Wood Distribution in Relation to Shoreline Armoring % 40 Miles 30 Unarmored Armored % 14% 15% 6.5% 0.5% None LWD Drift Logs Marine View Park 31

32 Armoring below Ordinary High Water reduces LWD and drift logs West Seattle-photo from WDOE 32

33 Shoreline Veg and Armor? Domninant Shoreline Vegetation in Relation to Shoreline Armoring Miles Unarmored Armored None Grass Shrubs Trees 33 From Higgins et al. 2005

34 What s up with those trees? Shoreline Tree Density in Relation to Shoreline Armoring % Miles Unarmored Armored 5 0 Continuous Dense Patchy 34 From Higgins et al. 2005

35 South of Vashon Landing, Vashon Island Piner Point, Vashon Island 35

36 Trees Overhanging the Shoreline in Relation to Shoreline Armoring Miles Unarmored Armored 5 0 Overhanging Not Overhanging 36 From Higgins et al. 2005

37 Loss of riparian vegetation Harbor Heights, Vashon Island Vashon Landing 37

38 Encroachment Sand Lance & Surf Smelt Spawning Area No Spawning Area 38

39 Changes in habitat suitability Armored= Armored= Armored-is lighter Natural is bold Relative Humidity Armored= Armored= Adapted from Rice

40 Chinook Diet in Downtown Seattle unarmored shoreline with some vegetation armored shoreline with very little vegetation Light grey= terrestrial insects Toft et al

41 Recent UW Study & = 41

42 Recent UW Study, continued Armored beaches are on average 15 to 30 feet skinnier than non-armored beaches Drift log area is on average 15 feet skinnier on armored beaches Density of insects much higher on unarmored beaches Unarmored beaches have more wrack Much more of it is of terrestrial origin Density of beach hoppers much higher on unarmored shorelines (due to wrack) 42

43 Sea Level Rise Seattle Tide Gage 8 inches in 100 yrs 43

44 44

45 (~5ft) ~8 inches (~2ft) 45

46 Sea Level Rise impacts/effects? Increase in high water/storm events Recent study in San Juan s predicted a doubling of long term bluff erosion rates 1ft increase in in sea level means an order of magnitude increase in high water events (turns a 10 year event into a 1 year event and 100 year event into a 10 year event) Expect increase in erosion rates Expect loss in shoreline habitats by coastal squeeze 46

47 47 Created by CGS for friends of the San Juans

48 Puget Sound Nearshore Ecosystem Critical zone of transition marine, freshwater, and terrestrial ecosystems Supports complex mosaic of habitats high productivity, complex food webs, large numbers of plants and animals The whole area is important Tidy is not natural Find softer and more creative ways to stabilize slopes & banks Trees are the answer Plan for changing Sea Levels 48 From the Daily Olympian

49 QUESTIONS? 49