The role of terrrestrial habitat in the population dynamics and conservation of pond-breeding amphibians

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on September 25, 2007)Vita.Thesis (Ph. D.) University of Missouri-Columbia 2007.I used both demographic modeling and experimental field research to evaluate the role of terrestrial habitat in the population dynamics and conservation of pond-breeding amphibians. I began by using literature data to develop stochastic, stage-structured demographic models for two pond-breeding amphibian species and used these models to determine the potential effects of a range of core terrestrial habitat areas on population size and persistence. I next carried out field experiments designed to improve model accuracy. First, I manipulated terrestrial densities of juvenile amphibians and followed individual growth and survival of over one year. Results suggest that terrestrial density should be considered in models of amphibian population dynamics. I also carried out field experiments to determine the effects of specific forestry practices on the survival of juvenile wood frogs and American toads. The results of these experiments indicate that forestry practices interact with existing landscape structure to determine microclimate and thereby influence amphibian survival. Returning to the model building process, I used the results of my field experiments to develop a demographic model designed to evaluate the potential effects of forestry practices on wood frog populations in Missouri.The results of my dissertation research indicate that the quantity and quality of terrestrial habitat available to pond-breeding amphibians can have substantial population level consequences including increased extinction probabilities and decreased population sizes.Includes bibliographical reference

Desiccation rates of Rana sylvatica, Rana clamitans, and Bufo americanus in a fragmented forest

Abstract only availableHabitat loss and fragmentation are the primary causes in the declines of amphibian populations. Farming, urban sprawl, and logging have created a mosaic of developed and undeveloped land that may create barriers between aquatic breeding sites and terrestrial refuges. While ponds and wetlands are important in early development and breeding, many species spend their adult lives foraging in the terrestrial environment surrounding a breeding site. An amphibian's ability to move and forage in a terrestrial environment is determined by their capacity to remain hydrated. We compared desiccation rates of wood frogs (Rana sylvatica), green frogs (Rana clamitans), and American toads (Bufo americanus) juveniles in different microhabitats of a forest and a clear-cut to determine how they might affect the terrestrial activity of amphibians. Using the experimental arrays created by LEAP (Land use Effects on Amphibian Populations) at Daniel Boone Conservation Area we set up cylindrical wire mesh enclosures in forest drainages, forest ridges, brush piles in clear cuts, and open areas in clear cuts at two ponds. Animals were placed in the enclosures during the evening and weighed every six hours for twenty-four hours. Soil moisture, and soil temperature were also measured every six hours. Analysis of variance with repeated measures was used to compare percent water loss in the habitat treatments. All frogs lost water; however, water loss was greater in the day compared to night. Brush piles within the clear cut slowed water loss compared to open areas in the clear cuts, and animals on forest ridges lost more water than those in forest drainages. Our results reinforce the need to protect forest drainages as terrestrial refuges and illustrate that clear cutting, even with brush piles as cover, may negatively affect the delicate balance of mortality and survivorship in juveniles, therefore threatening the future of a population.Life Sciences Undergraduate Research Opportunity Progra

Effects of Timber Harvest on Amphibian Populations: Understanding Mechanisms from Forest Experiments

Accompanying appendix may be accessed at: http://hdl.handle.net/10355/1365Harvesting timber is a common form of land use that has the potential to cause declines in amphibian populations. It is essential to understand the behavior and fate of individuals and the resulting consequences for vital rates (birth, death, immigration, emigration) under different forest management conditions.We report on experimental studies conducted in three regions of the United States to identify mechanisms of responses by pond-breeding amphibians to timber harvest treatments. Our studies demonstrate that life stages related to oviposition and larval performance in the aquatic stage are sometimes affected positively by clearcutting, whereas effects on juvenile and adult terrestrial stages are mostly negative

Effects of Timber Harvest on Amphibian Populations: Understanding Mechanisms from Forest Experiments. Appendix

Appendix only of an article to be published in BioScience by the American Institute of Biological Sciences.The Appendix provides a summary of results for four forest management treatments according to region, species, and response variables

Pond-Breeding Amphibian Community Composition in Missouri

Description of data: Site location data and amphibian species and numbers per life stage encountered at each research site in Missouri. Collected: 2002, 2005, 2006, 2012. Collection site: Missouri. Method: Collected from drift fences around ponds in 2002, 2005; dipnet and funnel traps in 2006, 2012