Detailed Description of Research Projects

Assessment of amphibian malformations on northeastern national wildlife refuges

This project is a collaborative effort with the USF&WS and constitutes a new activity. The main goal is to assess the extent and types of malformations of anurans on several national wildlife refuges in New England and New York. The first year of sampling (2001) focused on field assessments. The results of work conducted last year (together with work from previous years) were presented by a USF&WS collaborator at a recent conference and the resulting paper will be published in a peer-reviewed proceedings.

In addition to field surveys, I have, with my graduate students, initiated a number of lab and mesocosm experiments designed to examine sublethal effects of chemicals on amphibians. Developmental malformation is only one type of sublethal effect. Chemicals can alter tadpole growth and behavior, thereby increasing the chance of mortality through decreased growth and development (i.e., by not reaching metamorphic stage prior to pond drying) or predation. We have selected the herbicide Atrazine as our model chemical and will be conducting a series of multifactor sublethal effects experiments.

Developing a conservation strategy to protect land habitat functions for New Hampshire's reptiles and amphibians using Blanding's turtle as a flagship species

This project is a continuing effort that was initiated in 2000. The project involves extensive trapping in wetland complexes in Great Bay and in the Weare/Hopkinton area, as well as radiotracking of turtles to assess home range, habitat use, and movement patterns. We are entering the final year of radiotracking and will begin analyses and recommendations for designation of critical habitat in the upcoming year. This work has direct management and conservation application in the state, and the data are critical to the state's efforts to project the Blanding's turtle, which is a state species of special concern.

Spatial distribution of anurans in an agricultural landscape

This project was a large field study examining upland-wetland linkages and amphibian populations. What is particularly unique about this project if that is was conducted in an area where upland treed patches are the more limited habitat and wetlands are numerous. I was able to demonstrate very clearly that certain amphibian species are tied to these uplands patches and have limited dispersal through non-treed upland habitats (e.g., ranch lands). The results of this study will make an important contribution towards better integration of upland and wetland management for amphibians in Florida. I am just finishing the final report on this project and the major paper from this study will be submitted to Conservation Biology.

Direct and indirect effects of different predators on forest stream food webs

The project constitutes a large field manipulation to assess the impacts of different top predators (fish versus salamanders) on stream food webs. The first phase of field work was conducted last year but due to a ruptured disk in the doctoral student working on this project the remaining field work for the fall was suspended.

Phenotypic plasticity and inducible defenses in anurans

This area of research examines the impact of the presence of predators (i.e., on-lethal exposure) on amphibian morphological development. This is a fascinating and "hot" area of research. Anurans exhibit a great deal of phenotypic plasticity in response to various environmental factors; however, perhaps the most interesting is the responses that can be induced by predators. Simply the presence of a predator can induce changes in body shape, tail fin depth, and even coloration. During the past year, Emily LaFiandra (M.S. 2001) conducted three experiments addressing this issue. We just submitted one paper that is the first documentation of inducible defenses in the pinewoods treefrog (Hyla femoralis), a species in which predators induce strong morphology changes as well changes in tail coloration (from relatively clear to salmon color with black markings).