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eMammal Program at Prairie Ridge is Yielding Results

November 5, 2014

In October 2013, staff from the Biodiversity Lab and Prairie Ridge set out a series of 8 eMammal camera traps on the Prairie Ridge grounds to answer some basic questions about mammal populations, particularly how the large mammal population changes seasonally, whether the large mammal population is influenced by the small mammal population of the grounds, and whether different habitat types influence which species use those areas.  Our 8 traps have been maintained for over a year so far by a combination of staff and volunteers who move the cameras monthly, swap out the batteries, and replace the memory cards.  Volunteers then process the majority of the data before uploading it to the eMammal project.  So far, over 250 citizen scientists have participated in tagging the images with species data at Prairie Ridge, and hundreds more have taken part through an eMammal console in the Visual World Investigate Lab in the Nature Research Center.

So what have we found so far?  In the first four months of data collection, we captured 4158 pictures of wildlife, 407 of people, and 9 of domestic animals (mostly cats).  Prairie Ridge is being heavily used by wildlife.  White-tailed Deer are, unsurprisingly, the most common species we’ve spotted, followed by Eastern Gray Squirrels, Gray Foxes, and Eastern Cottontails.  Northern Raccoons, Virginia Opossums, and Coyotes were also commonly spotted on the grounds, though not quite as often as the top four.  Southern Flying Squirrels and Eastern Chipmunks, however, were only spotted a few times over the first four months and are not very common at Prairie Ridge.

Species detection rate graph

Some species are more commonly found in specific areas than others. Preliminary analyses suggest that habitat type does influence the biodiversity and activity of mammals on the grounds.  The White-tailed deer roam about the grounds and heavily use both the forested and open areas:

Deer map

Coyotes, Eastern Cottontails, and Gray Foxes show similar patterns, though they did not appear on every camera trap in every location.  Our Eastern Cottontails seem to avoid the woods along the creek, for example, and the Coyotes tend not to visit the forest along the upper part of the Forest Trail.  Other species are clearly restricted in their habitat preferences, such as the Eastern Gray Squirrels:

Squirrel map

The squirrels are frequently spotted in the forested areas, but avoid the other areas almost entirely.  The Virginia Opossums avoided the open bottomland of our arboretum entirely and seem to prefer the perimeter of the grounds to the interior.

Though we have only analyzed the data from the first four months so far, there were some interesting changes in mammal detection rates as fall transitioned into winter last year. White-tailed Deer, Gray Squirrels, Eastern Cottontails, Northern Raccoons, and Virginia Opossums all decreased during the winter compared to their fall levels.  The canines (Coyotes and Gray Foxes), on the other hand, were detected more often in the winter than in the fall.

Seasonal shifts graph

It’s interesting that the predators increased in the winter while the herbivores and omnivores decreased.  Could the predators play a role in the decreased detection rate of prey species?  We’ll need more data to find out!

The camera trapping program at Prairie Ridge is part of a multi-year study of mammal populations, so the data presented here from the first four months of data collection are still very preliminary.  We can’t, for example, really link mammal detection rates to seasonal shifts with only one season represented in the data analyzed so far, so it will be interesting to see if the same patterns hold this year.  The habitat information presented here may also change as we add more seasons to the analysis and collect data over multiple years.  We haven’t started to compare the large mammal population captured on our camera traps to the small mammal population, monitored quarterly by the Museum’s mammal collection curators, so we can’t even speculate on how the small mammal population may influence the large mammal population.  Every bit of data added to the analysis will add a little more to the overall story of our large mammal population at Prairie Ridge and help us understand how our natural wildlife haven in the heart of the Triangle Area is used by a variety of species.  It will be interesting to see whether the initial trends hold true from season to season and year to year.

Would you like to get involved in the Prairie Ridge eMammal project?  We are offering our next camera trapping program at Prairie Ridge on November 15th from 1:00-4:00pm! Details are available in the program listing.

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