Some cool body condition and diet results!

This last week Dr. Hopkins attended the annual conference for the International Association for Bear Research and Management in Ljubljana, Slovenia. While at the conference, he met with local collaborators and presented some preliminary results from the Maine Cooperative Bear Study...

 

In addition to estimating population abundance and density to inform bear management in the state, we hope to predict the body condition (an indicator of health) of bears when they emerge from their dens using information derived from hair, including stable isotope data. Our preliminary results suggest that although adult male and female bears had similar body condition throughout the state, bears along the southern distributional boundary in Maine had lower body condition (Unity College) than bears in the north (Spectacle Pond and Bradford; the latter being our study area).

 

Body condition of black bears in 3 study areas.

This finding contradicts much of what is currently thought about bears around Unity College being more "healthy" than other bears in the state. This finding does, however, support the hypothesis that recolonizing bears in the south are more nutrient-stressed because they live in a fragmented agricultural landscape with less important native foods available compared to conspecifics in the north that live in more contiguous forests with more native foods available.

We transformed stable isotope data from hair of bears in our study area (during previous years) to proportional dietary contributions and found that most bears forage for human-derived foods (~20% of diet), likely bait (see below), and that plants and animals are similarly important to bears (each being ~40% of their diet)!

 

Isotopic mixing space (left) transformed to proportional diet contributions for black bears in Maine (right). Important diet items include animals (red), human foods (i.e., bait; green), and plants (blue). Colored and gray lines in the right figure denote population- and individual-level diet contributions for bears, respectively.

Stay tuned for more cool results as we analyze samples we collected this summer and in the past :-)