RESEARCH
We use spatial data collected from satellite telemetry and site surveys to investigate third and fourth-order habitat selection. We are particularly interested in knowing how bears respond to changes in the availability of native and anthropogenic foods.
Noninvasive genetic sampling is commonly used to monitor bear populations in North America because such studies yield relatively high samples and detection probabilities without capturing, collaring, and tracking the movements of study animals via radio-telemetry. Instead of targeting bears for live capture, researchers use hair traps to target bear hair. Hair follicles contain DNA, which can be used to identify individuals for estimating population growth using mark-recapture models. This proven method for estimating population growth will be integrated into a new population model for black bears in Maine. In summer 2020, we will sample the bear population in the Mattamiscontis and Alder Stream study areas. In winter 2020, Jackson Laboratory will use SNPs to identify individual bears in the two study areas. We will use these individual genetic identifications to estimate the abundance and density of bears in each study area using spatially-explicit capture-recapture models.
Hard mast is an important food source for black bears, white-tailed deer, and turkeys in the Northeast United States. In Maine, black bears forage for acorns and beechnut in the fall to build fat reserves before entering the den. A past study found that some females synchronized their 2-year reproductive schedules with beechnut production, hard mast production contributes to reproductive success. Except for Maine, all New England states survey acorns and beechnut every year to inform their management programs. For this study, we will initiate the NE Mast Survey in Maine by surveying hard mast on Penobscot Indian Nation land throughout the state. Establishing a database would allow Maine to make more informed management decisions based on hard mast data.
The black bear health and comparative medicine program is a broad-based program with a one-health approach to the study of health and disease in the American black bear as a model species. Black bears are broad-ranging omnivores, and so may be a sentinel of health in their environment, and also directly impact health and well-being of nearby human populations through human-wildlife conflict and zoonotic disease, especially in areas where bears are harvested for food. The black bear has also emerged as an important species in comparative medicine, to help us understand conditions such as coronary heart disease, type II diabetes, chronic kidney disease, and Tay-Sachs disease. Through our research, CWS aims to advance understanding of the health of black bears in the northeast while enhancing animal welfare and individual animal outcomes during in-situ conservation and management work.
We will use a population projection matrix to estimate population dynamics over time in each Penobscot study area. Our projection matrix will be sex-specific and age-specific. We will use the following data sources to estimate the sex- and age-specific survival and recruitment of black bears in each study area: 1) summer captures; 2) winter den surveys; 3) fates of tagged bears (including collared bears) and problem bears; and 4) age-at-harvest records for bears throughout the state.
Nearly half of the northeastern states (47%) and provinces of North America use anthropogenic foods (e.g., corn, donuts, trail mix) as bait to lure black bears to locations where they are then harvested. Currently, little is known about the impact of hunting bait on the health, behavior, and population dynamics of black bears. Detecting individual bears that rely on bait and understanding any impacts on their behavior or health outcomes is of particular interest to wildlife management agencies because baiting bears is currently the most successful method for harvesting bears in Maine and other states; however, there may be unintended consequences from baiting such as increased densities, range expansion, and increased conflict in certain areas. In this study, we investigate the diets of bears in Maine (especially those that feed on bait), and the consequences of different diets on individual growth, health, and vital rates of bears.
To prevent human-wildlife conflicts in the future, we need to understand how conflict behaviors develops in populations. This is especially true for bears because human-bear conflicts are not limited to agricultural damage and livestock depredations, but often include incidents with people. Such conflicts can put both bears and people at risk of injury or death. While the solutions are more straightforward for other large carnivores (e.g., livestock protection measures against wolves), they are less so for omnivorous bears that have complex behavior. We ask, why are some bears involved in conflict and others are not?
The prevalence of chronic kidney disease (CKD) is rising worldwide and currently 10-15% of the global population suffer from CKD and its devastating complications. Given the increasing prevalence of CKD there is an urgent need to find novel treatment options. The American black bear (Ursus americanus) hibernates for up to seven months annually. During this period, they do not eat, drink, urinate, or defecate. Bear hibernation is a state similar to prolonged sleep during which body temperature is reduced by 1-8ᵒC, there is a 20-50% reduction in metabolic rate with a depressed heart rate, renal function decreases by 70%, the volume of urine produced is reduced by 95%, and there are signs of renal damage after hibernation. At the end of hibernation, the bear kidney is comparable to that of a human dialysis patient. We know that in humans, a dialysis patient does not recover unless they receive a kidney transplant. However, through unknown mechanisms, bears are able to regain full kidney function after coming out of hibernation and there are no signs of damage after several months. Understanding these mechanisms could lead to creating novel therapies for treating human CKD, recovery from acute kidney injury, and protecting the kidney from ischemic damage during transplantation.