Species Distribution Modeling for Bog Turtles (Glyptemys muhlenbergii) in North Carolina
Abstract
The bog turtle (Glyptemys muhlenbergii) is the smallest turtle species in North America
and is listed as a threatened species under the federal Endangered Species Act. Accurate
detection of its specialized wetland habitat and subsequent tagging of individuals
for monitoring purposes is critical for improving conservation efforts with this species.
Parts of the Piedmont region in North Carolina have historically served as habitat
for bog turtles, but few populations are now known to occur there. Increases in residential
development, agricultural land use, and the draining of wetland areas over the past
several decades have likely contributed to their current extirpation from this part
of the state. Most wildlife managers no longer survey for bog turtles in most of
the Piedmont as efforts are both time and cost prohibitive, and funding generally
all allocated for work in counties where they have a better chance of locating bog
turtles during a given survey event. Several managers acknowledge that there may
still be bog turtles living in the Piedmont, but because of present limitations, there
is currently no conservation plan for them. GIS and predictive modeling were used
as a low-cost method for locating potential sites within four North Carolina counties
that exhibit suitable habitat characteristics for bog turtles. Such predictions may
prove useful in documenting new occurrences of bog turtles in both the Piedmont counties
of Iredell, Davie, and Davidson, as well as in the higher quality bog turtle habitat
regions of Wilkes County. The Maxent distribution model was used as it is capable
of producing accurate habitat predictions for species with small sample sizes. A
total of 28 areas with species presence and 16 different environmental variables were
used in the analysis. The model returned several sites within Wilkes County exhibiting
higher levels of predicted suitability, and a smaller number of sites within Iredell
County with moderate levels of suitability. The predicted sites in Iredell County
were previously unknown to wildlife managers, and may help to direct future survey
work in those locations. If these model predictions can be translated to positive
detection of turtles in the field, spatial modeling work of this kind may begin to
play a larger role in the conservation efforts for the species.
Type
Master's projectSubject
Bog TurtleSpecies Distribution Modeling
endangered species
North Carolina
Maxent
Ecological Niche
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https://hdl.handle.net/10161/8177Citation
Dick, Kevin (2013). Species Distribution Modeling for Bog Turtles (Glyptemys muhlenbergii) in North Carolina.
Master's project, Duke University. Retrieved from https://hdl.handle.net/10161/8177.Collections
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