RESEARCH
On this page you will find brief descriptions of some of the various research projects that we are currently involved with. If you would like to find out more about any of the research described here, please contact me or my collaborators.
On this page you will find brief descriptions of some of the various research projects that we are currently involved with. If you would like to find out more about any of the research described here, please contact me or my collaborators.
MOVEMENT AND POPULATION ECOLOGY OF TIMBER RATTLESNAKES
This summer we will begin a long-term study of Timber Rattlesnakes in Ohio, seeking to understand movement, habitat selection, and population dynamics in relation to forest management. This research is being done in collaboration with Ohio Division of Wildlife, Ohio Division of Forestry, and the U.S. Forest Service. |
PATCH SIZE, POPULATION GENETICS, and PLETHODONTID SALAMANDERS
Red-backed salamanders are among the most cosmopolitan of amphibians, often inhabiting green spaces and forested urban parks. To determine the effect that population isolation and patch size have on genetic diversity, we will assess the genetic diversity of salamanders inhabiting forest patches in and around Columbus ranging from 5–500 hectares. |
METHODS FOR OPTIMIZING LANDSCAPE RESISTANCE SURFACES
The assessment of functional connectivity on the landscape has important implications for conservation and management, especially as it pertains to the preservation or establishment of critical habitat necessary for dispersal corridors. One of the greatest challenges faced by researchers is accurate assignment of resistance values to landscape features. Such assessments often rely on expert opinion, but unfortunately expert opinion often deviates significantly from how organisms actually perceive and respond to the landscape as they move through it. The approach I have developed requires no a priori assumptions about the relationship of resistance values. Using a combination of genetic algorithms and optimization functions you can thoroughly explore parameter space to determine the landscape resistance values that best explain pairwise genetic differentiation. An R package (ResistanceGA) has been created and added to GitHub (see R Projects). |
WETLAND MITIGATION AND LANDSCAPE CONNECTIVITY
In the United States, more than 95% of wetlands have been converted or destroyed. There are increasing efforts by land managers to construct wetlands, but often with limited understanding of the efficacy of their efforts or best practices to maximize function for herpetofauna. In collaboration with John Crawford, Andrew Kuhns, and Chris Phillips, we'll be working to evaluate how created wetlands function amphibians in terms of larval growth, recruitment, and survival. |
SOURCE-SINK POPULATION DYNAMICS
This is a collaborative project between the Semlitsch and Eggert labs at the University of Missouri to assess source-sink dynamics of Ambystomatid salamanders at Fort Leonard Wood. The focus of the project is on the ringed salamander (Ambystoma annulatum), which is a species of concern in Missouri. With this research we plan to integrate within pond larval dynamics, juvenile dispersal, metapopulation modeling, and population genetics to make long term management recommendations for this Ozark endemic species. Assessment of network modularity is identifying populations critical to maintaining gene flow at local and landscape scales. Network models are also being used to identify optimal locations on the landscape to create new wetlands to maximize metapopulation capacity. |
ELEVATIONAL DISTRIBUTION OF PLETHODONTID SALAMANDERS
The effects of climate change are becoming apparent; extreme temperatures and variable, flashy rain events are expected to be the new normal. As organisms that are closely tied to the abiotic environment and highly dependent on cool, moist habitat (Peterman and Semlitsch 2013), plethoodntid salamanders are likely to be impacted by these changes. In North America, the greatest diversity of plethodontid salamanders is harbored in the southern Appalachian mountains. There are many predictions concerning how montane species will response to changes in climate (particularly warming), with many models and empirical studies suggesting upward shifts in the lower elevation distribution. In order to assess such changes in distribution, a clear understanding of species' current distributions is necessary. In collaboration with John Crawford, Dan Hocking, and Joe Milanovich we are setting out to (1) rigorously define distribution of the salamander abundance across an elevational gradient in Great Smoky Mountain National Park; (2) establish long term monitoring sites and methods so that changes in abundance and distribution can be detected; and (3) assess population differences across elevational gradients. |
GENETIC DIVERSITY AND FITNESS IN PERIPHERAL POPULATIONS
In Missouri, the wood frog reaches the edge of contiguous Midwest distribution. Previous research (Peterman et al. 2013) revealed that genetic diversity and heterozygosity declined as the range margin was approached. To determine what the fitness consequences of these genetic differences are, we reared larval wood frogs in cattle tanks at the University of Missouri's Research Park. We measured growth rates, survival, time and size at metamorhosis, and post metamorphic survival rates. In collaboration with Matt Gifford, post metamorphic performance was also assessed. Preliminary results suggest that decreased genetic diversity significantly reduces growth, survival, and performance. |