The Effects of Urban Development on Pond-Dwelling Turtles in the Western Piedmont of North Carolina
A Grant Proposal for the Student-Development and Engagement Alliance ACS Environmental Program 2002
Kristine Grayson, Davidson College; krgrayson@davidson.edu
Introduction:
With the global population now topping 6 billion people, development and habitat fragmentation is fast becoming one of the greatest threats faced by wildlife (Sih, 2000; Dobson, 1996). As suitable habitat for species are reduced to smaller and smaller patches that are farther and farther apart, species become exposed to a host of problems associated with population fragmentation (Sih, 2000). Specifically, smaller and more isolated populations become prone to extinction due to greater susceptibly to environmental and demographic stocasticity (Dobson, 1996), introduced exotics, loss of the safety afforded by herding or schooling behaviors, and suffer from genetic problems associated with a small gene pool (decreased variation, inbreeding depression, and genetic drift) (Campbell, 1996). Populations are increasingly forced to rely on migration of individuals both to allow for mixing of genetic material and to found new populations, replacing ones that go extinct (Sih, 2000; Semlitsch 2000). Therefore, studies of the effects of development and the resulting habitat fragmentation on gene flow between populations are needed.
Freshwater, pond-dwelling turtles provide excellent models for studying the
effects of habitat fragmentation on metapopulation dynamics. These animals exist
in distinct, clearly defined populations (ponds, wetlands, etc.) that can be
easily studied. Although populations are restricted to aquatic environments,
these turtles have been shown to migrate across terrestrial habitats (Stone
et al., 1993; M. Dorcas, pers. comm.). Such migrations allow for gene flow between
populations and the founding of new populations. Aquatic turtles are also ideally
suited for long-term population studies. In addition to living in distinct populations,
they are long-lived and are easily captured and marked without harming the animal.
Project Description:
For conservation efforts to be successful, a broad spectrum of issues must be considered. A small isolated population, no matter how pristine the habitat, will not be successful if gene flow from other populations is not possible. To more precisely examine the degree of gene flow between populations, DNA analysis is needed. More specifically, I will use a very powerful genetic marker, microsatellite DNA. Microsatellite DNA are repeated sections of DNA code (1-6 base pairs), which can be used to compare populations due to the high variability and ease of scoring results (Sites et al., 1999; Zane et al., 2002). I will use microsatellite DNA analysis to examine the role of development and habitat fragmentation on the genetic diversity of populations of eastern painted turtles (Chrysemys picta) and eastern mud turtles (Kinosternon subrubrum) in the vicinity of Davidson, N.C. Microsatellite DNA will be isolated from small tissue samples of captured turtles (harmless to the turtles). Using microsatellite analysis, I will be able to quantify the relatedness of different populations (ponds) and estimate the amount of gene flow (migration) between populations. I will use geographical information systems (GIS; ArcView 3.2, ESRI, Redlands, CA) to evaluate the habitat and distances between ponds and use genetics to assess how these factors affect the amount of gene flow (migration) between populations. This study will allow me to draw conclusions about the detrimental effects of habitat fragmentation caused by human development poses for these turtles and provide recommendations for management and conservation of these species.
Evaluation and Dissemination:
This project will not conclude in one school year. It will be a project that
will be continued and expanded to other research areas. I will consider next
year a success if we can reliably perform the technique, sample both study sites,
and begin to successfully process these samples. Genetic analysis is often not
included in conservation research and I hope to demonstrate its importance and
feasibility. In the spirit of ACS's commitment to meaningful environmental projects,
this project will plant the seeds for conservation research continued beyond
first year of data collection and analysis.
My project will work with community landowners, as all potential study sites
are on private properties. In order that the results of my project may make
a meaningful contribution to area conservation efforts, I will provide my results
to the Davidson Land Conservancy (DLC). The DLC was established to identify
important property for conservation and work to set aside those areas. My data
will be valuable to help with these important decisions concerning which areas
are critical for protection. Though I cannot involve community members or students
with the data collection (as having multiple people at the ponds concerns landowners
with livestock because of the risk of the spread of diseases, such as foot-and-mouth),
I hope to educate students and community members through reptile out-reach days.
During these events, held at least once a year, we bring live amphibians and
reptiles of North Carolina out for the public to see and hold in hopes of educating
them about their importance.
I will use this as an ACS model project where one student can lay the groundwork
for a long-term project that can be applied in many fields and lead to other
potential areas of research and conservation. I will provide specific information
on this project to the Davidson community by presenting a poster at the annual
Davidson Biology Department poster fair. Other projects that will be presented
with an environmental emphasis include JD Willson's box turtle project. I will
make information available to the general public via e-mail and a project web
site describing my methods. In addition, I am very interested in applying for
circuit rider funding and providing individualized consultation with other ACS
institutions. Eventually, the results of this project will be submitted to a
peer-reviewed scientific journal for publication and published in popular outlets,
such as North Carolina Wildlife.
This project will:
1) Serve to engage students in conservation-oriented scientific research.
2) Serve as a model for other ACS institutions that are interested in developing
scientifically based conservation initiatives.
3) Provide future students opportunities to conduct conservation-oriented scientific
research.
4) Address the effects of urbanization on wildlife, an important issue in global
sustainable development.
5) Supply data to the Davidson Lands Conservancy to aid in the identification
of areas critical for conservation.
6) Provide a project that will raise awareness of environmentalism and conservation
issues on the Davidson campus through the presentation of a poster at the Biology
Department poster fair in the Spring of 2003.
Works Cited:
Campbell, N. A. Biology. Benjerman/Cummings Publiching Co.
Inc., Menlo Park, Ca.
Dobson, A. P. 1996. Conservation and biodiversity. Scientific
American Library, N.Y.
Semlitsch, R. D. 2000. Principles for management of aquatic-breeding
amphibians. J. of Wildlife Management 64:615-631.
Sih, A. 2000. Habitat loss: Ecological, evolutionary, and genetic
consequences. Trends in Ecology and Evolution 15:132-134.
Sites, J., N. FitzSimmons, N. da Silva, and V. Cantarelli.
1999. Conservation genetics of the giant Amazon river turtle (Podocnemis expansa;Pelomedusoidae):
Inferences from two classes of molecular markers. Chelonian Conservation and
Biology 3: 454-463.
Stone, P., J. B. Hauge, A. F. Scott, C. Guyer, and J. L. Dobie.
1993. Temporal changes in two turtle assemblages. J. of Herpetology 27: 13-23.
Zane, L., L. Bargelloni, and T. Patarnello. 2002. Strategies for microsatellite isolation: a review. Molecular Ecology 11: 1-16.