by Jan Mackie
Dr Martyn Obbard gives us the details on the black bears of the Bruce Peninsula. Very fascinating and informative. And gives us food for thought on how we might live better with these unique creatures.
To hear an audio recording of the talk click here.
The June meeting was a joint venture between the Bruce Peninsula Environment Group and the Sources of Knowledge, held at the Visitors Centre at the Park and was well attended.
Brian McHattie introduced Dr. Martyn Obbard, now retired, an Emeritus Research Scientist with OMNR&F and a professor at Trent University.
In 1996/7 there were concerns about the black bear population on the Bruce Peninsula which had not been previously researched. Dr. Obbard embarked on a project for which there is data between 1998 & 2012.
Originally the project was a 3-year collaborative agreement between MNR & Parks Canada with support from managers. Funding was shared with the MNR bringing in graduate students
The concerns were: 1. Possible isolation of the BP bears, 2. Possible small population, 3. Habitat fragmentation, 4. Human-Bear conflict
The objectives of the project were: A) what is the size of the bear population on the Peninsula and B) Is the genetic diversity sufficient for the population to be sustainable.
The field work began in late summer of 1998. That year only one female bear was outfitted with a radio collar. Traps made from old oil drums with a trap door were used. In 1999, 14 bears were radio collared, giving the research team the ability to track their movements. When the bears are live trapped they are sedated, weighed, examined for age & health and given a radio collar. These collars are only placed on the females as the neck of the males is too thick and they can slip the collar off. These collars allowed the researchers to track the bears’ movements and locate the bears in their dens in the winter to gather information about numbers of cubs being born.
Bears ranged in size from: males – 64 to 128kg – females 60.5 to 78.8kg and newborns are tiny, approx. 300grms. From information gathered it was estimated that there were approx. 316 bears on the peninsula in 2012.
The winter work of the research team consisted of tracking the females in their dens when the cubs would be 8-10 weeks old. Each female has 2 or 3 cubs per winter and remains somewhat awake to tend to the cubs, nursing & grooming them. Dr Obbard entertained us with the Mercer Report episode of finding the winter dens and extracting the cubs & mother to weigh them and check on their health.
To determine the genetic diversity of the peninsula bear population hair traps were set. A sample of hair would be left on the barbed wire when the bears passed under it for the bait. DNA from these samples and from the live traps showed that the bears on the Bruce peninsula are genetically unique, differing from other bear populations in Ontario. This lack of diversity could be an issue for the sustainability of the population and the idea of occasionally introducing a bear with different DNA is an option that researchers are looking at.
The dens of the peninsula bears are also unique – of the ones the researchers visited, 80% were in deep rock crevices, a few were excavated under brush piles or overhanging boulders. This crevice den is not found amongst other bears in Ontario.
This separation from other Ontario bears is likely due to the bottleneck at the base of the peninsula created by development.
If the bear population were reduced to just the park, within 50 years the bears would be gone. One more threat has appeared in the last couple of years in the form of the Beech bark disease that is currently threatening the entire population of Beech trees. Beech nuts provide an important staple to their diet.
In order to reduce the risk of extirpation (wiping out of this unique population) there is the need to 1. Conserve habitat outside of the park (dense mixed and deciduous forests), 2. Reduce incidental mortality (roadkill), 3. Reduce overall harvest (hunting), 4. Reduce proportion of the adult female harvest.
All of us who live on and visit the peninsula have a part to play in keeping this unique bear population from going into serious decline. One simple thing we can do to reduce the possibility of human-bear conflict is by not leaving food & garbage out to attract the bears. We need to put our garbage out only on the day of collection. If you are a weekend visitor your garbage can be taken to the Lindsay landfill site (for full info go to www.northbrucepeninsula.ca ) that is open on Sundays during the summer until 6pm OR take it home where you can add it to your local collection system. And if you rent out your cottage be sure to leave information available to encourage visitors to be aware & deal with food & garbage appropriately.
To watch the Rick Mercer video of his visit to a bear den with mother and cubs, accompanied by Dr. Obbard, click here.
Copyright (c) Bruce Peninsula Environment Group, 2018