Un-bear-able

Throughout most of the world humans have exterminated carnivores in order to keep their places of habitation safe, and while large carnivores still exist in patches we have a sort of "You keep to your side, I'll keep to my side," sort of attitude towards them. The problem, however, is that we keep expanding our towns and villages out into areas where large carnivores live, some areas experiencing an increased level of conflict. Leopards eat stray dogs in the slums of Mumbai, wolves kill dogs left outside in Alaska, black bears raid trash cans in New Jersey suburbs, and even polar bears are starting to head into towns with a greater frequency as the local ecology changes. I don't list such incidents to say that we're experiencing some sort of epidemic and that carnivores should again be killed without mercy, but rather that we are changing ecology on local and global scales that can often bring large carnivores into contact with people. Sadly, human deaths do sometimes result due to this close proximity, but carnivores are an essential part of many ecologies and tragedy can often be avoided with proper education and management.

As we change the landscape through development, some species die out while others thrive, omnivores and generalists usually faring much better than specialists. The black bear (Ursus americanus), oddly enough, represents one of the success stories of animals that have thrived as land is increasingly modified for human use, largely through gaining large amounts of food from trash cans. In my own state of New Jersey the presence and abundance of black bears has been controversial, some advocating active management of their numbers through a regulated hunt while others have argued for no action whatsoever, but black bears are often a problem in the norther part of the state. Other states that are how to black bears have been experiencing similar problems, and so Rocky D. Spencer, Richard A. Beausoleil, and Donald A. Martorello carried out a survey of 48 wildlife agencies in the U.S., Canada, and Mexico to see how these groups dealt with human/bear interaction.

What the researchers found generally fit with the growth trend in black bear populations and increasing human interaction; annually there appeared to be about 43,237 complaints about black bears, 82% of the responding agencies indicating that complaints about the bears were "common" to "increasingly common" to a "serious problem." Most of the complaints, though, centered around food attractants, specifically garbage, followed by lower levels of problems with crops and bee-hives, attacks on people being rare compared to all other incident types. Wildlife agencies responded in most cases by visiting the site, capturing the bear, and then relocating the bear or killing it, the issue of kill permits to hunters being the least common response. Within agencies that did relocate bears, though, there was a sort of 2-3 strike policy where bears that returned to areas and continued to be a problem were ultimately euthanized.Outside of relocation, rubber bullets and loud noises were most often used to try and condition bears to avoid certain areas, but only half of the agencies that responded said that they used bear-resistant garbage containers, these containers most often purchased via outside funds due to an lack of money. The use of such containers, being a more preventative measure, was found to be generally favored over relocation and euthanasia, but this presents us with a bit of a paradox.

Even though the vast majority of agencies said that relocation didn't work the relocation and marking of problem bears was the most common response of the agencies, yet few groups kept data on the bears that had been released and whether they came back. As the authors of the paper note, it seems that the move to relocation is based more upon social pressures from communities than actual study and understanding of what the bears are doing, the process being one of reaction to bears rather than taking care of the problem at its source. Indeed, outside of agencies actively developing a database of problem bears and their behaviors (something that is of scientific value as well as conservation value), the most important thing that can be improved is the utilization of bear-resistant garbage containers and education. Unfortunately containers can be expensive and require the coordination of the townspeople and local waste management companies, cooperation that is not always forthcoming, but this move would likely greatly reduce the bear problems as most of the encounters center around garbage. Hopefully the paper will spur agencies to keep better records and push for preventative measures to be taken in order to keep bears and people out of conflict with each other.

Polar bears (Ursus maritimus) are much larger and generally more dangerous than black bears, though, and a recent paper looking at the Hudson Bay population by Regehr, Lunn, Amstrup, and Stirling reports that we might expect more conflict between people and polar bears in that region, specifically in the area of Churchill. It's well understood that polar bears depend on sea ice for hunting, the earlier breakup of sea ice due to climate change having a detrimental impact on polar bear populations. Normally polar bears in the Western Hudson Bay are deprived from seal prey for about 4 months during summer and autumn, the bears relying mostly on fat reserves until the sea freezes up again, but due to increases in temperature the sea ice melts 3 weeks earlier than it did about 30 years ago, forcing the bears off the ice. This problem has led polar bears to seek food more often in places inhabited by humans, from Inuit villages to towns, leading to an increase in the quota for the number of bears that could be killed despite the fact that the population has been declining since the 1980's. Indeed, the increased presence of bears being due to desperation and not to a population increase, and the current quota for the hunt does not appear to be sustainable. Hardest hit, though, were young bears and the oldest bears in poor condition that could not survive a longer amount of time with less food. Mortality of young bears in general also seemed to go up as female bears lost more cubs due to ecological changes, breeding again and again losing more cubs instead of being able to keep the cubs with them until the time of weaning about 2 years later.

The findings of the researchers have important implications for more northern populations of polar bears, as well. The West Hudson Bay group lives near the southern end of the range of polar bears, among the first to be affected by higher air temperatures, and if the climate continues to warm similar problems will be experienced in areas to the north. This is going to create some severe management problems as bears will likely turn to garbage and other products of human settlement if they cannot get the food they need naturally, populations being whittled down not only because of ecological changes but also because of hunting and the elimination of problem bears. While the most northernly populations might actually gain a bit of a boost from some warming, allowing them to access areas that were previously closed in ice and had to be traversed to get to the hunting areas, we don't know to what degree the climatic changes will occur, especially when it's predicted that climate change will be more severe at the poles.

References;

Regehr, E.V.; Lunn, N.J.; Amstrup, S.C.; Stirling, I. (2007) "Effects of Earlier Sea Ice Breakup on Survival and Population Size of Polar Bears in Western Hudson Bay." The Journal of Wildlife Management Vol. 71 (8), pp. 2673-2683

Spencer, R.D.; Beausoleil, R.A.; Martorello, D.A. (2007) "How agencies respond to human-black bear conflicts: a survey of wildlife agencies in North America." Ursus Vol. 18 (2), pp. 217-229