| It is clear from reported changes in our natural environment that sustainable economic development must be balanced with the conservation of biodiversity. In order to understand how to achieve this goal, our research will examine mechanisms of population persistence in the context of major land-use practices. A central tenet of conservation biology is that connectivity among fragments of usable habitat and interactions with adjacent degraded habitats are the keys to understanding the impacts of land use on population dynamics, risk of extinction, and maintenance of biodiversity. The LEAP project takes an experimental approach that can increase our understanding of these problems in an important vertebrate group, amphibians. Specifically, our research will provide new insights directed at basic demographic and behavioral mechanisms maintaining local populations and connecting populations in fragmented habitats that are essential for persistence. These results will provide solutions at two levels: 1) Scientists will gain a better underdstanding of how harvest practices affect amphibians and pragmatic solutions to minimize impacts; 2) conservation agencies and natural resource managers will have mechanistic solutions to critical conservation problems such as preventing extinction and maintaining biodiversity of amphibians in the face of land use. |
The focus of our research is to understand how important population processes in pond-breeding amphibians are altered by land-use practices that fragment natural habitats. Extensive field studies and experiments strongly indicate that two processes, local population dynamics and dispersal, are critical for population persistence and may be limiting factors for amphibians in landscapes fragmented by human activities. Thus, our research focuses on experiments that test responses linked to these two processes: 1) local population dynamics - the ecological and demographic processes related to larval metamorphosis and recruitment of juveniles into the breeding population, and therefore local population size and those available for dispersal; and 2) dispersal and migration - the behavioral process of individual movement through terrestrial habitats for reproduction at home ponds or for dispersal to nearby ponds, and therefore connectivity and recolonization. We are in the process of establishing four (n=4) replicate experimental arrays at each of three regional study sites: Maine, Missouri, and South Carolina. Each experimental array will be oriented |
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around an existing natural pond with four delineated terrestrial quadrants (~4 hectares each). Each quadrant will be randomly assigned a forest management treatment: 1) complete clearing with coarse woody debris (CWD) removed, 2) clearing with coarse woody debris retained,
3) partial cutting (25% of basal area), and 4) uncut forest control. The treatments were selected to incorporate
three major practices that have been hypothesized either to harm or mitigate the loss of amphibian populations
such as clearing land of trees and CWD for building site preparation or planting, clear-cutting of trees for efficient
100% timber harvest, and retention of CWD or partial (25%) harvest. We believe that this research will: 1) increase
understanding of basic ecological processes of population persistence, and 2) have strong implications to current
conservation, management, and land-use practices. Further, we believe that our results will be applicable to species
protection, especially for threatened or endangered species (e.g., flatwoods salamander, Ambystoma cingulatum
; gopher frog, Rana capito ; red-legged frog, Rana aurora ). |
Aerial Photograph of Maine LEAP Gilman Site
The terrestrial habitat surrounding each wetland area will be divided into four quadrants of 2.5 ha.
Each quadrant will receive one of the following experimental treatments:
1. Control forest - no cut
2. Clear-cut with coarse woody debris (CWD) removed
3. Clear-cut with CWD retained
4. Partial cut of 25% basal area
