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The SLOSS Debate and Beyond Outline 1. Island Theory and The

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The SLOSS Debate and Beyond Outline 1. Island Theory and The GE/BI307 Mar 10, 2007 Outline Reserve Design: The SLOSS debate and Beyond 1. Island theory and the SLOSS question. 2. Point and counterpoint 3. Beyond SLOSS: what have we learned about reserve design? 1. Island theory and the SLOSS question. Touching off the debate: Diamond J. 1975. The island dilemma: lessons of modern biogeographic studies for the design of natural reserves. Biological Conservation 7:129-146. Species-Area relationship predicts larger areas contain more species. ‘bigger is better’ Taken at face value, this suggests that 1 large reserve should contain more species than several smaller ‘SL better than SS’ reserves totaling the same area. ‘closer better’ ‘circular better than linear’ ‘connected better than isolated’ ‘minimize edges’ Other key ‘pro-SL>SS paper: Contrarians: Simberloff DS, Abele LG. 1976. Island Biogeography theory and conservation practice. Science 191:285-286. Terborgh J. 1976. Island Biogeography and conservation: Strategy and Limitations. Science 193:1029-1030. Daniel Simberloff – Lawrence Abele – U. Tennessee (via Fl. State) Florida State University 1 Simberloff argument: Response from Diamond: When z<1 (always the Larger areas are more likely to contain the wide-ranging case) half the area species that are often most threatened. preserves more than half the species. The sum of species in small areas may exceed a large area, but may be composed of generalists and weeds. Thus, two reserves of ½ area may contain more than the species in the full area. What key assumption does this depend on? Why several small can be better than single large: 1. Habitat diversity. 2. Focal species conservation, e.g Cape Floral Province Cape Floral Province: -68% of species are endemic -53 species of endemic Proteacea species restricted to 1 or 2 populations -Each population occupies 5 km2 or less, contains less than 1000 individuals. -A few large parks would completely miss many of these species. -Many smaller, scattered parks would be more effective in this case. Whatever the merits of Diamond’s geometric reserve design recommendations, all would agree that these simple rules have been adopted uncritcally (e.g. 1980 World Conservation Strategy, “I suspect workers are growing more weary of it than World Conservation Union) approaching any agreement on its resolution” – Craig Shafer Nature Reserves: Island Theory and Conservation Practice 1990 I wholeheartedly agree… 2 Beyond SLOSS Types of focal species: Consensus: 1. Keystone species: many others depend on it (e.g. Beaver) 2. Umbrella species: large range protects many other species (bear) Strategies for conservation depend on the group of species under 3. Flagship species: public appeal (e.g. great blue heron) consideration and specific circumstances. (shift to autecological 4. Indicator species (frogs) focus from synecological focus). 5. Vulnerable species: Endangered Species List. Corralary: There has been a shift away from Equilibrium Theory and toward Minimum Viable Population/ Minimum critical size analysis. Large reserves are desirable, but well-managed small reserves have an important role in protecting focal species of value. Recognizing the importance of buffers and corridors for focal species: Marine reserves: •Most island biogeography theory has been applied to conservation of terrestrial habitats, not marine. •Aquatic reserves largely under-studied. -Dispersal mechanisms, characteristics largely unknown. - Pollution may have more subtle/widespread effects in aquatic systems than in terrestrial Effective corridors must be designed with care – e.g., many animals move along riparian zones but not other pathways. Conservation strategies Humans and Nature Apart: -Primack “Protected areas are a seductively simple way to save nature from -The role of humans humanity. But sanctuaries admit a failure to save wildlife and natural habitat where they overlap with human interests, and that means 95% or more of the earth’s surface. Conservation by segregation is the Noah’s Ark solution, a belief that wildlife should be consiged to tiny land parcels for its own good and because it has no place in our world. The flaw in this view is obvious: those land parcels are not big enough to to avert catastrophic species extinciton by insulratization or safe enough to protect resources from the poor and the greedy. Simply put, if we can’t save nature outside protected areas, not much will survive inside; if we can, protected areas will cease to be arks”. D. Western et al. 1989. 3 Case study: Marine Reserve Design Key challenges to marine reserve design: Focus area: Gulf of California. -Almost no application of an increasing body of theory of large 1st step: Gather data on habitats and species. marine reserves. -Some theory suggests need to protect >20% of habitat for fisheries, but no agreement on how much habitat needed to protect biodiversity. -No consensus on how to maintain ecological links (connectivity) between reserve elements. A priori goals: 1. Protect 20% of each representative habitat 2. Protect 100% of rare habitats & areas with highest species richness. 3. Protect ecosystem function by protecting larval sources and larval connectivity through dispersal (keep food chain from collapsing) Thus, this is habitat and community focused more than focused on single species. 4 Methodological Approach: 1. Make an educated guess about larval dispersal: 100 km max. A. Gather Spatial Information on: 2. Use sophisticated geometric optimization model: 1. Fish diversity as a function of geography (latitude, depth predict 66% of fish diversity) “Spatially explicit simulated annealing algorithm (SITES/SPEXAN) 2. Area of each habitat Interfaced with a GIS system (ESRI Arc View).” 3. Larval sources (diving and interview fisherman) “This algorithm designs and analyzes portfolios of sites from a B. Create maximum reserve map preserving all diversity, then universe of territorial units… attempts to meet predefined, whittle it down based on: quantitative conservation goals using as few sites as possible” - smallest number of reserves that meet % protection - constrained by 100 km distances between any 2 units. goals and ensure larval connectivity. Many possible combinations of reserve number, size, and separation distance. How to optimize? Biologically and socio- Biologically optimal network economically optimal network. -includes overlay of fishing intensity maps. Key result: This approach did not significantly decrease the number Key benefits of this approach: of desired conservation goals -objective method (more politically defendable) -Stepwise procedure (biologically optimal -> socially acceptable) presents policy makers with ability to weigh costs and benefits, set priorities. Key limitation: based on shaky information of dispersal distances. Likely to affect marine reserve designs for a long time. 5 Case study from New Guinea: (Diamond 1986) Important to keep in mind: 1. Political Geography/zoning, as in most other cases, looms large, but particularly interesting in New Guinea: - Irian Jaya under strong centralized govt. (Indonesia). Top- down control over land use/zoning. Relatively easier to implement national nature reserve system. - Papua New Guinea – much more political power rests in local communities, tradition of freedom from higher authority. Nature reserves will depend much more heavily on local decisions. Diamond focuses on Irian Jaya. shrews Sorex vagrans, vagrant shrew Sorex palustris, water shrew Mustela erminea, short-tailed weasel Marmota flaviventer, yellow-bellied marmot Long-tailed Vole, Microtus longicaudus Golden-mantled Ground Squirrel Northern Pocket Gopher, Spermophilus lateralis Belding’s Ground Squirrel Thomomys talpoides (Spermophilus beldingi) Unita chipmunk Eutamias umbrinus 6 Neotoma cinerea, Bunker's Woodrat Zapus princeps, western jumping mouse American Pika, Ochotona princeps Lepus townsendi, snowshoe hare Case study: Marine Reserve Design Key challenges to marine reserve design: -Almost no application of an increasing body of theory of large marine reserves. -Some theory suggests need to protect >20% of habitat for fisheries, but no agreement on how much habitat needed to protect biodiversity. -No consensus on how to maintain ecological links (connectivity) between reserve elements. Focus area: Gulf of California. 1st step: Gather data on habitats and species. 7 Black coral Rodoliths – ‘unanchored’ coral algae Broomtail grouper – commercially important, large ranging Goliath grouper – commercially important, large ranging 8 A priori goals: Methodological Approach: 1. Protect 20% of each representative habitat A. Gather Spatial Information on: 2. Protect 100% of rare habitats & areas with highest species richness. 1. Fish diversity as a function of geography (latitude, depth 3. Protect ecosystem function by protecting larval sources and predict 66% of fish diversity) larval connectivity through dispersal (keep food chain from 2. Area of each habitat collapsing). Focus on large commercial fish. 3. Larval sources (diving and interview fisherman) B. Create maximum reserve map preserving all diversity, then Thus, this is habitat and community focused more than focused on whittle it down based on: single species. - smallest number of reserves that meet % protection goals and ensure larval connectivity. Many possible combinations of reserve number, size, and separation distance. How to optimize? Biologically optimal network 1. Make an educated guess about larval dispersal: 100 km max. 2. Use sophisticated geometric optimization model: “Spatially
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