Getting to Know Connecticut's Black Bears

Bears Home | Story Map | The Research Question | Methods | Results | Kudos & Links

This research was conducted by Michael Evans, PhD student and Dr. Tracy Rittenhouse of the Department of Natural Resources and the Environment, UConn. Storymap created by Michael Evans and Cary Chadwick, UConn CLEAR.

Background

Black bears (Ursus americanus) have become an unmistakable presence in Connecticut. As their population has grown, these adaptable omnivores have expanded their range to include both rural and suburban areas of the state, bringing them into close proximity with people. Black bears’ increasingly conspicuous presence has raised many questions about the Connecticut population. Research being conducted at the University of Connecticut aims to better understand the effects of development and land-use patterns on black bear ecology and behavior in Connecticut. One of the biggest research questions is, how many bears call Connecticut home? Scroll down to learn more about how researchers are aiming to answer this question and check out the interactive storymap showcasing some of the research results.

The Storymap

To showcase the results of this research, Michael Evans and Cary Chadwick (University of Connecticut, College of Agriculture, Health and Natural Resources) teamed up to create an interactive storymap. Check it out for yourself!

 

The Details: A Research Question

Conflicts between bears and people are often the most attention-grabbing patterns resulting from population expansion.  This research first sought to identify landscape characteristics and patterns that are associated with the highest rates of conflict.  Not only will this understanding help predict where future conflicts are likely to occur, but also provide insight into how development can be designed to minimize the potential for such incidents.

 

One of the most basic, yet important questions, is how many bears call Connecticut home?  The University of Connecticut is collaborating with DEEP to create the first scientifically-based estimate of the number of black bears in Connecticut. Beyond a simple count, we also want to know how bear densities change among different patterns of human land-use.  By defining these relationships, DEEP will better be able to anticipate how the bear population will be distributed in parts of Connecticut that have not yet been recolonized.

 

Methods

DEEP has maintained a database recording all reports of interactions between bears and the public – sightings, vehicle collisions, trash raiding, etc. – including the addresses at which they occur.  The locations of all instances of bears damaging property were mapped from 2008 - 2012, and compared the landscape characteristics between places experiencing high and low rates of conflict.  This process involved first testing which combination of factors are actually associated with conflict rates, and then measuring that relationship.

Genetic methods were used to identify individual bears from the DNA contained in their hair. Using new quantitative techniques that expand on the traditional mark-recapture population estimates, these DNA fingerprints are used to estimate local abundance and density.  So how do you gather enough hair to figure out how many black bears reside in Connecticut? Amazingly, the bears donate it themselves. Small ‘hair corrals’ are used to passively collect bear hairs in a non-invasive manner. These consist of barbed wire strands stretched between trees to form an enclosure. When bears cross the low strung wire to investigate interesting scents placed in the center of these corrals, hair is snagged on the barbs. The simple genius of this method lies in the bounty of data that can be collected without capturing the animals. Genetic data can also be used to identify the distance that young bears disperse.  

 

Results

Important features predicting human and bear conflict included percent forest cover, the density of forest edges, housing density, and household income.  Importantly, the highest rates of conflict within intermediate forest cover, and higher amounts of edge forest.  In total, the integration of housing within forest – a pattern of development that occurs throughout CT – promotes conflicts between bears and people.  These findings suggest that development patterns that cluster housing and preserve contiguous blocks of forest will be most successful in minimizing human-bear conflicts.

Changes in black bear density are most strongly associated development.  More so than whether areas are forested, or non-forested.  The highest concentration of bears were found in ‘exurban’ development – areas with between 6 and 50 houses/km2.  A North to South decline in bear densities suggests that the population has been recolonizing CT from the north, and may continue to increase in southern parts of the state.

 

Kudos & Links

This research has been conducted by Michael Evans, PhD student and Dr. Tracy Rittenhouse, both in the Department of Natural Resources and the Environment at the University of Connecticut. This research is funded primarily with Wildlife Restoration funds from the Connecticut Department of Energy and Environmental Protection (DEEP) Wildlife Division and supported by assistance from DEEP wildlife biologists Paul Rego and Jason Hawley.

 

Getting to Know Connecticut's Black Bears - Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment, UConn

 

Research Article:

Exurban land use facilitates human-black bear conflicts, Journal of Wildlife Management, 2014

 

In the News:

Understanding Connecticut's Wildlife - UConn Today, September 2013

Keeping Track of Black Bears - The Day, August 2012