The Science of GIS and Marine Reserve Design

Transcription

1 Matt Schult NRS 509 Project 26 November, 2007 The Science of GIS and Marine Reserve Design Over the past few decades, marine protected areas (MPAs) have been touted as a cure-all for ailing ocean ecosystems; their design began essentially by necessity without much thought beyond where to place them and who was to be protected. The surge in development was in large part due to coastal resource and fisheries managers efforts to augment insufficient regulatory practices, which were not effectively inhibiting system degradation (Airame et al. 2003). MPAs are intended to benefit communities by conserving marine biodiversity and maintaining productivity while contributing to economic and social welfare. An ideally designed MPA might accomplish these objectives. Since interests often clash, standardized, objective techniques can help to bypass any shortcomings in cooperation (Villa et al. 2002). Although some are complimentary, each objective requires its own set of considerations relying on ecology and oceanography, as well as economics and social concerns (Aswani & Lauer 2006). Demanding such detailed insight, reserve design as a science is simultaneously becoming more complex and specialized. MPAs can be small, species-specific refugia that have simple limitations concerning particular species of concern (Airame et al. 2003). At the other end of the spectrum are the more complicated, multiple-use sanctuaries that often need to balance conflicting objectives (i.e., tourism vs. reef protection) (Villa et al. 2002). In all fairness, the science of instituted MPAs is relatively fresh, yet has undergone rapid progressions, especially in the recent decade. The drive in this evolution can be credited to improvements in geographic information systems (GIS) and remote sensing. These are essential data acquisition and analysis tools that present scientists with higher elements of accuracy, objectivity and clarity in communicating results to stakeholders. There are three focal aspects to MPA design and management, and GIS is crucial for each: data acquisition/analysis for establishing objectives, for siting purposes, and for evaluating overall success. Objectives for reserves are carefully constructed plans based on informed decision-making. Obtaining information is essential to wisely constructing reserves. One innovative method integrated indigenous knowledge of marine ecology, substrate type and habitat associations into GPS-delineated biophysical boundary maps for the Solomon Islands (Aswani & Lauer 2006). The dataset was created by interviews with local fishermen, ground-truthing via SCUBA survey and orthophoto overlays. This method helps bring GIS and management back to the sphere of local authorities, strengthening the connect between stakeholders and researchers. In Italy, researchers combined design priorities concerning social pressures, development needs and conservation requirements with GIS to carry out spatial multiple-criteria analyses on regions proposed for MPA establishment (Villa et al. 2002). This analysis assessed the concordance of a potential reserve s fit with the prioritized set of objectives for different degrees of regulation. Approaches like these are gradually becoming standardized and globally applied. Remote sensing via multispectral satellite imagery yields data to be analyzed based on the characteristics of reflected light. Information gleaned from this feedback can detail phytoplankton blooms, benthic habitat characterization and composition of protected mangrove forests or ocean circulation patterns. A large portion of work has been carried out using IKONOS satellite data. Launched in 1999, it pioneered satellite imaging by combining high spatial (1m panchromatic) and temporal resolution imagery, providing a thorough time-series readily digitized and analyzed in GIS (Dahdouh-Guebas 2002). In pitted tests, it was found to be best suited for mapping the boundaries of habitat patches, although incapable of assigning patch type within habitats (Mumby & Edwards 2002).

2 When it comes to satellite data acquisition on habitats, the general consensus is that it is only cost-effective if: (1) independent field data exists for confirmation, (2) mapping regions are small (~500km 2 ) and (3) patches on the scale of <10m are the targeted subject (Mumby & Edwards 2002). This was determined for most, including CASI, Landsat TM and SPOT satellites. Concerning habitat characterization, two limitations are that patch size is often below, and therefore subsumed into coarser pixel sizes, and spectral analysis cannot (as of yet) accurately differentiate spectral signals of photosynthetic organisms, be they eelgrass beds, phytoplankton, macroalgae or coral zooxanthellae. Remote sensing of physical properties (sea surface height, temperature, wind speed/direction, phytoplankton blooms) allows scientists to map the forces influencing ocean circulation both in space and time (Palumbi et al. 2003). Ocean currents are directly responsible for larval dispersal patterns, hence are critical to siting reserves. Mapping dispersal potential by currents can qualify regional degrees of connectivity which helps determine spacing and locating of reserves. Connectivity is crucial since larvae might settle adjacent to spawning (self-seeding reserve) or drift far away to support remote stocks (Palumbi et al. 2003). Protection of upstream sources of recruits is important for conservation; the aim is to build a network of interdependent reserves forming linkages between source and sink (Roberts 1997). Designing reserves in this fashion is elemental to achieving the protection objectives listed at the outset of this overview. Establishment of a reserve is really just the beginning of the science, the effort continues with monitoring and assessment studies on reserve effects. For protected mangrove reserves GIS is used to create reliable vegetation maps of (mangrove) species abundance and distribution (Kairo et al. 2002). With these maps managers can monitor changes in forest cover and estimate productivity, keeping management protocols updated to maintain optimal standing stocks and prevent degradation (Dahdouh-Guebas 2004). Despite higher multi-spectral resolution of satellite technology, as of 2004 aerial photography remained the tool of choice for vegetation mapping. In tropical nations this often remains the only option. A complex use of GIS in MPA assessment was conducted in the Mediterranean, where spatial models predicted catch-per-unit-effort (CPUE), a standard measure of commercial fishery productivity (Stelzenmuller et al. 2007). Fisheries data were incorporated into a GIS spatial model to map modeled and actual gradients in CPUE between georeferenced grid cells encompassing established MPAs and habitats of special concern. This analysis would be laborious to chart manually, and even more difficult to interpret without the digital layout of GIS. Fisheries reserves can also be assessed by digitizing reserve layouts and tracking habitat utilization by particular fish. Tracking of individual fish by tagged hydrophone surveys is especially useful since the average reserve is only 16km 2 (Mumby & Edwards 2002). Observational records support georeferenced grid-square analyses to indicate frequency of occurrence within protected habitats by species slated for conservation (Meyer et al. 2000). Reserve monitoring programs utilize remote sensing to measure changes in cover for coral reefs, eelgrass or other special habitats. Large-scale natural disasters or anthropogenic disasters can be mapped through satellite imagery. Live coral heads possess different reflectance properties than dead corals; by this it is possible to differentiate the two with infrared imagery. This helps to quantify impacts to these important communities following regional disturbances such as bleaching events or earthquake upheavals (Palumbi et al. 2003). This technology also enables scientists to work on much larger scales with greater efficiency. With only 10% variation between methods, using high resolution (1m) multispectral imagery, researchers were able to map coral plots in one hour of flight time what had cost three days to survey underwater (Mumby et al. 2001). The connecting theme in these publications is the appreciation for GIS as an integrative tool to collate data from disciplines as diverse as ecology, sociology, geography or economics. GIS is acknowledged for its ability to efficiently update, retrieve

3 and display information, as well as conduct comparative analyses quickly (Kairo et al. 2002). A final advantage is the manageable lower cost as a monitoring tool, compared to the efforts and resources required for field surveys. It is a bittersweet predicament that secures GIS a strong future in MPA science. It has long been predicted that coral reefs in particular will endure mounting stresses associated with increasing global carbon dioxide levels. GIS has proven its worth as a monitoring tool for temporal shifts in coral cover, saving researchers precious hours of data collection and interpretation. Impacts on a global scale will not be practical to monitor manually. Fortunately, advances in satellite imagery are progressing faster than a literature search can report. Based on the runaway rate of technological developments over the past half century, it is not unreasonable to expect high-quality satellite imagery to soon be a globally accessible tool. Some speculate though, that these improvements may initially lead scientists to trip over their own analytical shoelaces with spatial details displaying overwhelming internal variations (Dahdouh-Guebas 2004). This technology has only been at its current level for just over a decade, and most studies have intensively focused on ground-truthing the imagery. After this ground-imagery relationship has been studied sufficiently, certain proxies will likely develop based on consistent experiences reducing the need for ground-truthing. One interesting challenge posed is the integration of past and current data to forecast future trends by post-calibration of technique and the existence of time-series data (Dahdouh-Guebas 2004). Until that next break-through, GIS will at least continue to dissolve the divide between scientific and political languages and improve researchers chances of getting home in time for dinner more regularly. ANNOTATED BIBLIOGRAPHY Airame, S. et al., Applying ecological criteria to marine reserve design: A case study from the California Channel Islands. Ecological Applications, 13(1): s170-s184. Another paper from the landmark special issue of Ecological Applications concerning marine reserve science, the major focus here is in designing the reserve by incorporation of diverse datasets. GIS was used as the representative bridge between all physical, environmental and societal parameters that go into establishing a reserve. The questions on hand when designing protection areas always start with where, how large and how much? GIS answered these by overlaying maps based on habitat, bathymetry, sediment structure, commercial/recreational usage and distribution of special concern species. The authors followed a very methodical thought process and used high-order decision siting algorithms (modeling software SITES v.1), wide-spectrum data collection to create an array of protection scenarios. This tool is quite valuable for communicating conservation projections to the public and to decision-makers. Aswani, S. and M. Lauer Incorporating fisherman s local knowledge and behavior into Geographic Information Systems for designing marine protected areas in Oceania. Human Organization, 65(1): One of the more recent publications, this paper takes an innovative approach to the human sector of marine science and GIS data collection. There is a blend of database building from interviews with local parties, inventory of catch/habitat association from boat logs, and ground-truthing derived data with transect scuba surveys. All corners are covered for the human-use outlook on protected areas. The key difference in this paper is the use of GIS as a tool to collect and represent local fisheries data from indigenous perspectives rather than from the subjective Western regulatory vantage. Local knowledge is an invaluable asset to conservation, geo-spatial referencing of indigenous marine ecological knowledge is an innovative approach to reserve design.

4 This visualization aids in representing biogeographically zones, elements of habitat diversity and shifting intensities in the fishery based on seasonality or other environmental conditions. It is fortunate that these scientists have taken the approach they have, as this data is complimentary to quantitatively collected environmental data. The fact that the two approaches can communicate their data cooperatively via GIS serves as stand-alone testimony to the technologies promising future. This said it is in the author s favor that they acknowledge the need to validate anecdotal data with scientific habitat mapping, so the lack thereof cannot be claimed as a falling point in this paper. Chapman, M.R. & D.L. Kramer Movements of fishes within and among fringing coral reefs in Barbados. Environmental Biology of Fishes, 57: This paper is not especially exhaustive in GIS applications, but what it does cover extensively is the tracking of fish movements and usage within protected habitat, supported by GIS analysis. The paper reports on an excellent study of an Antillean coral reef reserve, tracking the movement of fish by means of mark-recapture trappings. Divers mapped the layout of each reef study grid using compass and measuring tape. The data they created by this means was superimposed on an aerial photo of the reserve and spatially analysed using MapInfo software. Statistics were performed to calculate the median ranges of the fish, show frequency of capture (spillover) out of the reserve and habitat usage within the reserve. The authors applied GIS where it is most important, in orienting their study site along with tracking movements of the subjects. Far more advanced approaches are available, involving radio-tracking of individuals as reported by satellite telemetry. The scope of this study, I feel, was too small spatially (400m 2 blocks), but also too large concerning sample-size (~1400 fish tagged ) to fully utilize advances in remote tracking. The data this study provides is essential to reserve design, and can be readily adapted to more advanced GIS, beginning with GPS point-tracking as an improvement. Kairo, J.G., B. Kivyatuand and N. Koedam Application of remote sensing and GIS in the management of mangrove forests within and adjacent to Kiunga Marine Protected Area, Lamu, Kenya. Environment, Development, Sustainability 4: There is an impressive assemblage of methods applied in this study, covering the evolution of GIS from aerial photography and Stereoscope interpretation, through groundbased mapping/navigation to correlate ground features and photo properties, in the end creating a GIS digital vegetation map. The authors of this paper used aerial photography groundtruthing along with toposheets (1:50,000) to create vegetation maps (1:25,000) of protected mangrove forests along Kenya s shoreline (Kiunga MPA). Their aim was to determine overall standing volume, species composition and size distribution of mangrove trees within the park. This information was used to build a GIS database of mangrove productivity as a means to support sustainable management. With this approach, the local economy can still benefit while optimally protecting the mangrove habitat. In the article, the authors lament the absence of GIS-based science in Kenya; granted access, however, they have exhaustively applied its capabilities to quantify their natural assets. An example of this eagerness is their wise expansion of their study site beyond the perimeter of the reserve, seeking to catalog the comparative over-exploitation of mangroves around the periphery of protected areas. Mumby, P.J. and A. Edwards Mapping marine environments with IKONOS imagery: enhanced spatial resolution can deliver greater thematic accuracy. Remote Sensing of the Environment, 82: In the fast-developing era of remote sensing, this paper evaluates current technologies for cost and thematic accuracy with the aim of finding a sufficient

5 combination to map marine habitats. The focus was to pit IKONOS satellite data against an array of alternate satellite sensors to determine strengths and limitations. Finding limitations of these sensors, the authors then pursued alternate methods to optimize the sensors output. This paper addresses methods of improving spectral resolution and overall thematic accuracy, including variance filters, texture algorithms, ground-truthing and postincorporation of high-resolution pixels. Results varied, finding that sensor suitability changes according to habitat studied (sand, coral, eelgrass?), degree of coarseness for discrimination (by species, by type?) and size of area studied. Problems run into in these cases were mismatch between resolution sizes (30m 2 ) and patch size (on average 20m 2 ), at best supporting analyses for interhabitat rather than intrahabitat variability. The authors successfully designated these sensors suitability to study conditions; this paper can be a useful reference in deciding which technology to apply in a monitoring program based upon budget, application, and desired scale/resolution output. The amount of effort and detail that went into this study serves to benefit those aiming to incorporate GIS capabilities into their management protocols. Mumby, P.J. et al A bird s-eye view of the health of coral reefs. Nature 413 p This paper investigates the application of spectral remote sensing analysis to monitor the health of coral reef ecosystems in comparison to the previously effortintensive in situ video surveys. The science of monitoring is integral to tracking changes in large protected areas over time, and the effort this has taken is in need of stream-lining. Their comparison found that aerial mapping of coral cover allows more efficient monitoring at a far larger scale while producing equally accurate results. Granted the resources, the authors predict this developing technology will replace the time-intensive ground surveys monitoring ecologically sensitive areas, with the added benefit of reducing observer impact in such areas. Given the large-scale impacts to ecosystems generated by climate change and development, this may not be far-fetched, but satellites as of yet cannot replace the experiential data obtained by direct scientific observation. However, one inarguable advantage is that spectral imaging data is immediately available in objective numerical format, reducing processing time needed to manually generate estimates of surface cover. A brief overview of a project with very important ramifications for MPA monitoring, this paper serves as a great advocate for transfer to remote sensing analysis where possible. An aspect this paper does not consider is the financial constraints of each method, which can also be a limiting factor; but perhaps this is too much detail for such a brief overview. Stelzenmuller, V., F. Maynou and P. Martin Spatial assessment of benefits of a coastal Mediterranean Marine Protected Area. Biological Conservation, 136: Conditions in the regions and fisheries surrounding Marine Protected Areas (MPAs) vary in space and time, making research into their efficacy a delicate task. The aim of this paper was to develop a geostatistical method to assess reserve benefits to regional fisheries in heterogeneous coastal reserves. This tool could be applied to predict spatiotemporal trends in fisheries catch to assess regulatory control for conservation benefits associated with protected areas. The approach was not so much to monitor the reserve, but more so to develop a model predicting effects of the reserve on the surrounding region. GIS and geostatistical tools were used to combine spatial and fishery data to create prediction grids per species targeted, studied over the spatial variables listed. These grids served as base layers for modeling and mapping spatiotemporal trends. The

6 main result was the creation of a grid-based density gradient showing change in catch per unit effort (CPUE-standardized measure) with respect to the spatial variables listed. This paper was initially confusing to digest, mostly for how many ways the authors applied the term spatial, but their analysis was thorough and involved to extents beyond the scope of this paper alone. Several publications could have been derived from this project, but this publication succeeds in presenting their geostatistical contribution to the science of MPA design. Villa, F. L. Tunesi and T. Agardy Zoning multiple protected areas through spatial multiple-criteria analysis: the case of the Asinara Island National Marine Reserve of Italy. Conservation Biology, 16(2): Techniques covered by the authors blend scientific, statistical and geomatic methods to create what is essentially a geospatial decision matrix for establishing MPAs. Their approach is unique, and somewhat novel. Multiple-criteria analysis is a method of presenting objective, prioritized values based on several, non-corresponding criteria, as described by Cochrane & Zeleny (1973). Their application of advanced GIS analysis to graphically portray these results in coverages is innovative. They consider all angles of MPA design, from varying levels of protection, regulatory objectives, and the degree of permitted activity within the region. A theoretical concordance model was built from this analysis, measuring the overall suitability of the reserve based on the previous considerations. These values were attributed to GIS layers, and overlaid on land use maps, and then rank-categorized to decide which type of reserve would be best suited to particular zones of the study site. Their overarching aim was to create a repeatable, consistent protocol for scaling MPA design to regional needs with both consistency and objectivity as key priorities. Meyer, C. G., K. N. Holland, B. M. Wetherbee & C. G. Lowe Movement patterns, habitat utilization, home range size and site fidelity of whitesaddle goatfish, Parupeneus porphyreus, in a marine reserve. Environmental Biology of Fishes 59: This study follows the behavioral patterns of a species of concern along with its utilization of a marine protected area (Coconut Island reef, HI). This is an essential science to monitor reserves and determine if they are properly designed. Geographic referencing techniques were combined with surgically implanted radio transmitters to track individual fish along the protected reef for the duration of the transmitters lives. The data obtained was used to define minimum convex polygons for the range covered and also to display positional frequencies of each fish by grid-square analysis. This information is equally useful to fishermen looking to exploit this species behavioral patterns as much as scientists seeking to protect these fish with minimal regulatory impacts. This paper doesn t claim final authority on reserve design, although they do prove this reserve is compatible for the goatfishes needs. Reserves should not be designed nor assessed based on a particular species needs-an approach once widely heralded-but currently focus on ecosystem-based protections. Studies such as this help piece together the large picture, however, so it is not a wasteful science to apply georeferencing tools in studying how species of interest appreciate their new protections. One weakness in this study is the negligence to report accuracies and errors of both the acoustic tracking method and the mapping utilities. Assigning microhabitat usage per individual fish would require fairly fine resolution on the data. REFERENCES Airame, S. et al Applying ecological criteria to marine reserve design: A case study from the California Channel Islands. Ecological Applications 13(1): s170-s184.

7 Aswani, S. and M. Lauer Incorporating fisherman s local knowledge and behavior into GIS for designing marine protected areas in Oceania. Human Organization 65(1): Dahdouh-Guebas, F The use of remote sensing and GIS in the sustainable management of tropical coastal ecosystems. Environment, Development and Sustainability 4: Kairo, J.G., B. Kivyatuand and N. Koedam Application of remote sensing and GIS in the management of mangrove forests within and adjacent to Kiunga Marine Protected Area, Lamu, Kenya. Environment, Development, Sustainability 4: Meyer, C.G., K.N. Holland, B.M. Wetherbee & C.G. Lowe Movement patterns, habitat utilization, home range size and site fidelity of whitesaddle goatfish, Parupeneus porphyreus, in a marine reserve. Environmental Biology of Fishes 59: Mumby, P.J. and A. Edwards Mapping marine environments with IKONOS imagery: enhanced spatial resolution can deliver greater thematic accuracy. Remote Sensing of the Environment, 82: Mumby, P.J., J. Chisholm, C.D. Clark, J.D Hedley & J. Jaubert A bird s-eye view of the health of coral reefs. Nature 413: Palumbi, S.R., S. D. Gaines, H. Leslie and R. Warner New wave: high-tech tools to help marine reserve research. Frontiers in Ecology and the Environment 1(2): Roberts, C.M Connectivity and Management of Caribbean Coral Reefs. Science, New Series, 278(5342): Stelzenmuller, V., F. Maynou and P. Martin Spatial assessment of benefits of a coastal Mediterranean MPA. Biological Conservation 136: Villa, F. L. Tunesi and T. Agardy Zoning multiple protected areas through spatial multiple-criteria analysis: the case of the Asinara Island National Marine Reserve of Italy. Conservation Biology, 16(2):