Can You Hear Me Now? Environmental Factors Affecting Anuran Diversity and Distribution in Gettysburg National Military Park

Rose Fogliano, Gettysburg College
Elizabeth E. Donovan, Gettysburg College

Environmental Studies Senior Capstone

Description

With amphibians declining at alarming rates worldwide, documentation of where species are currently found and comprehension of the factors affecting these distributions become ever more important. These goals are particularly crucial in National Parks because of their mission to preserve natural and cultural resources for future generations. We surveyed 30 sites at ponds, streams, and a vernal pool across Gettysburg National Military Park, where a variety of natural and anthropogenic influences are at play. Because anurans (frogs and toads) contribute most to amphibian decline and can be accurately detected via calls in the spring, we chose to focus our study on species within this order. At each site, we acquired acoustic data for three nights from sunset to sunrise using passive recorders. We determined the presence of 10 species in Gettysburg National Military Park: Northern Cricket Frog (Acris crepitans), Eastern American Toad Bufo (Anaxyrus americanus americanus), Fowler's Toad Bufo (Anaxyrus woodhousei fowleri), Chorus Frog (Pseudacris triseriata), Gray Treefrog (Hyla versicolor), Northern Spring Peeper (Pseudacris crucifer crucifer), Bullfrog (Lithobates catesbeiana), Green Frog (Lithobates clamitans melanota), Pickerel Frog (Lithobates palustris), and Wood Frog (Lithobates sylvatica). This confirms the presence of nine of the ten species previously found in the park with absence of Northern Leopard Frogs (Lithobates pipiens) and the addition of Northern Cricket Frogs. We found temporal variation overnight, but no overall trends across days. Correlations of species richness and environmental factors revealed a negative relationship between species richness and discharge. Additionally, sites with less canopy cover were found to have significantly higher species richness. Rain significantly predicted the presence of Eastern American Toads and Bullfrogs, while discharge significantly predicted the presence of Wood Frogs and Gray Treefrogs. We did not find any connections between biodiversity and distance from roads or land use in terms of either species richness or individual species presence. However, we cannot rule out the influence of anthropogenic factors on anuran diversity. We recommend that Gettysburg National Military Park continue to study anuran diversity through the use of acoustic recording and start a long-term monitoring program for diversity across all taxa.

 
Apr 29th, 3:30 PM Apr 29th, 4:30 PM

Can You Hear Me Now? Environmental Factors Affecting Anuran Diversity and Distribution in Gettysburg National Military Park

Glatfelter 102

With amphibians declining at alarming rates worldwide, documentation of where species are currently found and comprehension of the factors affecting these distributions become ever more important. These goals are particularly crucial in National Parks because of their mission to preserve natural and cultural resources for future generations. We surveyed 30 sites at ponds, streams, and a vernal pool across Gettysburg National Military Park, where a variety of natural and anthropogenic influences are at play. Because anurans (frogs and toads) contribute most to amphibian decline and can be accurately detected via calls in the spring, we chose to focus our study on species within this order. At each site, we acquired acoustic data for three nights from sunset to sunrise using passive recorders. We determined the presence of 10 species in Gettysburg National Military Park: Northern Cricket Frog (Acris crepitans), Eastern American Toad Bufo (Anaxyrus americanus americanus), Fowler's Toad Bufo (Anaxyrus woodhousei fowleri), Chorus Frog (Pseudacris triseriata), Gray Treefrog (Hyla versicolor), Northern Spring Peeper (Pseudacris crucifer crucifer), Bullfrog (Lithobates catesbeiana), Green Frog (Lithobates clamitans melanota), Pickerel Frog (Lithobates palustris), and Wood Frog (Lithobates sylvatica). This confirms the presence of nine of the ten species previously found in the park with absence of Northern Leopard Frogs (Lithobates pipiens) and the addition of Northern Cricket Frogs. We found temporal variation overnight, but no overall trends across days. Correlations of species richness and environmental factors revealed a negative relationship between species richness and discharge. Additionally, sites with less canopy cover were found to have significantly higher species richness. Rain significantly predicted the presence of Eastern American Toads and Bullfrogs, while discharge significantly predicted the presence of Wood Frogs and Gray Treefrogs. We did not find any connections between biodiversity and distance from roads or land use in terms of either species richness or individual species presence. However, we cannot rule out the influence of anthropogenic factors on anuran diversity. We recommend that Gettysburg National Military Park continue to study anuran diversity through the use of acoustic recording and start a long-term monitoring program for diversity across all taxa.