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Announcements. Reading Assignments BSCI363: Chapters 4 and 5 CONS670: Chapters 8 and 15. Tragedy of the Commons. The Value of Ecosystem Services. Costanza, R et al. 1997. The value of the world's ecosystem services and natural capital. Nature 387 :253-260. Deforestation of the Seafloor.
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Announcements • Reading Assignments • BSCI363: Chapters 4 and 5 • CONS670: Chapters 8 and 15
The Value of Ecosystem Services Costanza, R et al. 1997. The value of the world's ecosystem services and natural capital. Nature 387:253-260.
Deforestation of the Seafloor • The area of seabed trawled worldwide is ~ 150 times greater than the area of forest clearcut each year (an area twice the size of the lower 48 United States). • Although some spots escape trawling by chance or because they don't have fish, each square foot of the world's continental shelves is trawled every ~ 2 years Watling et al. 1998. Disturbance of the seabed by mobile fishing gear: a comparison with forest clearcutting. Cons. Biol. 12. 1180-1197. http://www.mcbi.org/btrawl/wnpaper.html
Marine Reserves • Based on a review of more than 100 marine reserves • population densities were on average 91% higher • biomass was 192% higher • average organism size was 31% higher • species diversity was 23% higher • Responses tended to be rapid (1-2 years after protection) and persistent (> 40 years). The Scientific Theory of Marine Reserves. AAAS Session: Science and the Biosphere, 2001.
Marine Reserves • Reserves may contribute to recruitment both inside and outside of reserve boundaries • Fisheries interests should benefit from this spillover, recruitment enhancement, and sustainable harvest. The Scientific Theory of Marine Reserves. AAAS Session: Science and the Biosphere, 2001.
Outline • Ecosystem Ecology • Biodiversity and ecosystem services • Ecosystem services • The economic value of ecosystem services • Biodiversity Management • Equilibrium Theory of Island Biogeography • Modern Approaches
Species Area Curves S = CAZ (log S) = Z (log A) + (log C) From: Gotelli, N. J. 1995. A primer of ecology. Sunderland, MA: Sinauer Assoc. 1-206 p.
Equilibrium Theory of Biogeography Species richness on islands or habitat patches is a balance between colonization and extinction
Colonization Dynamics Mainland pool of spp., “P” Colonization Island spp., “S” P # Island Species C declines to 0 where # island species = P (no more colonists available)
Extinction Dynamics Mainland pool of spp., “P” Extinction Island spp., “S” P # Island Species E is proportional to the total number of species. E reaches its maximum value at P
Turnover Dynamics and Island Spp. Richness Turnover (i.e., E or C) Extinction T S Colonization P # Island Species T = point where extinction rate = colonization rate. T determines the species richness for an island (S).
Nonlinear E and C Pattern and conclusions are identical for linear and nonlinear E and C Turnover (i.e., E or C) Turnover (i.e., E or C) E E T T S S C C P P # Island Species # Island Species
Review: Metapopulation Models • E decreases as patch size (area) increases. • C increases as distance between patches decreases.
Area Effect Turnover (i.e., E or C) ES P EL SS SL Colonization SS SL # Island Species P
Distance Effect Turnover (i.e., E or C) P CN Extinction CF SN SF SN SF # Island Species P
Number of Species on an Island Turnover (i.e., E or C) P CN ES CF EL SNS SNL SFS SNS SFL SNL SFS SFN P # Island Species
Application of Island Biogeography The good, the bad, and the ugly . . .
Distance and Species Richness From: Gotelli, N. J. 1995. A primer of ecology. Sunderland, MA: Sinauer Assoc. 1-206 p.
Contributions of ETIB • Metaphor of refuge as an island or spaceship • Interest in the fragility of the biota of individual refuges and causes of this fragility • Rules of refuge design? Hanski, I. A., and G. M.E., editors. 1996. Metapopulation biology: ecology, genetics, and evolution. San Diego, CA: Academic Press. 512 p.
“Island Biogeographic” Reserve Rules: IUCN, WWF Good: Make reserve as large as possible Bad: Scaling is species / process specific Ugly: Abandon small reserves ? Good: Potentially increase connectivity Bad: Effectiveness remains unclear Ugly: Increase synchrony of populations ? Good: True for spp. w/ large range req. Bad: False for spp. w/ small range req. Ugly: Not based on ETIB ? Good: True for “interior” spp. Bad: False for “edge” spp. Ugly: Not based on ETIB
Fundamental Problems w/ ETIB? • Alternative explanations for species-area relationship • Sampling • Habitat diversity • How do we define TURNOVER? Species Area (Samples)
ETIB and Forest Reserves Pimm, S. L. 1998. Ecology: The forest fragment classic. Nature 393:23-24.
ETIB and Forest Reserves • Spp. lost in small fragments • Top predators • Primates • Army ants and company • What about frogs? • Limited by breeding sites • Peccaries
Reserve Rules vs. Reality • Reserve design will be species specific. • Reserve design will be site specific. • The idea of “optimal” reserve design may miss the point entirely. • We are rarely faced with these alternatives. • ETIB is considered by many to be a “false start” in Conservation Biology
Application of ETIB • Application of ETIB to reserve design has been widely criticized • “Faunal collapse” refers to the loss of species following insularization. • Broadly accepted • Basis for many estimates of extinction rates • Caveats • Considerable error when used for prediction
Extinctions of large mammals in parks and reserves Newmark, W. D. 1995. Extinction of mammal populations in western North American national parks. Conservation Biology 5: 67-78.
Application of ETIB McDonald, K. A., and J. H. Brown. 1992. Using montane mammals to model extinctions due to global change. Conservation Biology 6: 409-415.
Application of ETIB McDonald, K. A., and J. H. Brown. 1992. Using montane mammals to model extinctions due to global change. Conservation Biology 6: 409-415.
Application of ETIB McDonald, K. A., and J. H. Brown. 1992. Using montane mammals to model extinctions due to global change. Conservation Biology 6: 409-415.