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Talk will be available at Lab Website Google: Skelly Yale. Global Amphibian Decline. Take Home Points. Upland Conversion Eliminates Amphibian Populations Isolation Fosters Extinction Most Amphibians Are Specialists Successful conservation requires a diversity of dynamic wetlands.
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Talk will be available at Lab Website Google: Skelly Yale
Take Home Points • Upland Conversion Eliminates Amphibian Populations • Isolation Fosters Extinction • Most Amphibians Are Specialists • Successful conservation requires a diversity of dynamic wetlands Context Matters.
Tolland Manchester Yale Forest 0.3 inds / ha* 1.3 inds / ha 7.8 inds / ha 85% Forested 78% Forested 37% Forested 5% Impervious 8% Impervious 20% Impervious
Lost Diversity Across 60 Connecticut Wetlands Species Disappear from Developed Wetlands Skelly Unpublished
Land Conversion: Wetland Size & Isolation Gibbs 2000
Land Conversion: Wetland Isolation Gibbs 2000
Land Conversion: Wetland Isolation Gibbs 2000 Gibbs 2000
Transect 10 x 2 km Orange, CT 295 People/sq km Milford, CT 846 People/sq km Fragmentation: ‘Rural’ to Urban Gibbs1998
Fragmentation: ‘Rural’ to Urban Gibbs 1998
Fragmentation Leads to Local Extinction Species Loss In Intact Forest Patches Species Differ Gibbs 1998
% of ponds occupied by spotted salamanders is higher when uplands are intact forest Species are frequently missing from vernal ponds in deforested landscapes Homan et al. 2004
Isolated Wetlands are less likely to have persistent amphibian populations Skelly et al. 1999
Whole Pond Experiment: Yale-Myers Forest Manipulated canopy in 6 wetlands in late 2001 then monitor population & community Responses At each wetland: ca. 25 overstory stems removed on S upland
Canopy & Temperature Open Closed
Following Cut in late 2001, new species have tended to move into Cut ponds. Reduced Canopy Tends to Increase Number of Species Skelly Unpublished
Following Cut in late 2001, wood frogs have remained abundant Altered Canopy Does Not Affect Wood Frog Abundance Skelly Unpublished
Following Cut in late 2001, spotted salamanders may have Increased. Spotted Salamanders May be Even More Abundant with Altered Canopy Skelly Unpublished
Amphibians as Canopy Specialists Generalist – Few Species Threshold – Most Species
Most species that can tolerate low light can occupy more wetlands Data for 8 Species
No single wetland type provides habitat for all amphibian species Canopy Generalist Spotted Salamander Marbled Salamander American Toad Open Canopy Specialist Closed Canopy Specialist
How can we conserve Wetland Dwellers? • Protect Wetland and Upland Units • Develop Proactive Landscape Level Plans • Avoid Use of Mitigated Wetlands • Bigger is not better • Stormwater catchments are typically poor habitats • Allow/Foster Wetland Dynamics • Wetland Diversity in Space and Time • Beaver • Selective Cutting
Take Home Points • Upland Conversion Eliminates Amphibian Populations • Isolation Fosters Extinction • Most Amphibians Are Specialists • Need a diversity of dynamic wetlands Context Matters.
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References • Gibbs JP 1998. Distribution of woodland amphibians along a forest fragmentation gradient Landscape Ecology 13: 263-268. • Gibbs JP 2000. Wetland loss and biodiversity conservation Conservation Biology 14: 314-317. • Halverson, M. A., D. K. Skelly, J. M. Kiesecker, and L. K. Freidenburg. 2003.Forest mediated light regime linked to amphibian distribution and performance. Oecologia 134:360-364. • Semlitsch RD 2000. Principles for management of aquatic-breeding amphibians Journal of Wildlife Management 64: 615-631. • Semlitsch RD, Bodie JR 2003. Biological criteria for buffer zones around wetlands and riparian habitats for amphibians and reptiles Conservation Biology 17: 1219-1228. • Semlitsch, R. D. and D. K. Skelly. 2007. Ecology and conservation of pool breeding amphibians. Pages 127-148 in Vernal Pools: Ecology and Conservation of Seasonal Wetlands in Northeastern North America (A. Calhoun and P. deMaynadier, Editors). CRC Press. ISBN 0849336759 • Skelly, D. K., E. E. Werner, and S. A. Cortwright. 1999. Long-term distributional dynamics of a Michigan amphibian assemblage. Ecology 80:2326-2337. • Skelly, D. K., M.A. Halverson, L. K. Freidenburg, and M. C. Urban. 2005. Canopy and amphibian biodiversity in forested wetlands. Wetland Ecology & Management. in press.