Computer models expose humans as main cause of caribou decline
If not for humans, the number of woodland caribou in northern Alberta would be seven times greater than it is now, a new study from the University of Alberta shows. Since 1987, woodland caribou in Alberta have been classified as threatened under the Alberta Wildlife Act.
"Caribou feed mostly on lichens that are typical for old-growth forest stands," said Piotr Weclaw a PhD student at the U of A. "They need a pristine ecological environment with large areas of old-growth forests in order to survive, and most things that disrupt the natural environment will be detrimental to them."
"In this manner, studying caribou is especially important because caribou are what we call an 'indicator' species, meaning how well they do is generally a good indicator to gauge the overall health of the forests where they live," he added.
Working in the U of A Department of Renewable Resources, Weclaw and his PhD supervisor, Dr. Robert Hudson, developed computer models that simulate the ecosystem of a 20,000 square km area in northern Alberta. They introduced different variables into the models to see what effect, if any, the changes had on the development of the simulated ecosystem. Some variables included altering the number of wolves (a caribou predator), moose (the main prey of wolves), and edible vegetation in the area. As well, a "natural" model--the ecosystem as it would be without any humans and thus no industrial development--was created, as was a "business as usual" model, with no changes from current conditions.
The models show that human activities stood out overwhelmingly as the variable most responsible for the woodland caribou's decline in northern Alberta. The models also showed that woodland caribou could coexist with uncontrolled wolf populations in northern Alberta, but if human developments continue at the current rate, the number of woodland caribou in the area will drop sharply in about 15 years, and continue dropping until they are eliminated from the area in 37 years.
"Based on the simulation experiments, we suggest the most detrimental factor on caribou population dynamics is the functional loss of habitat due to avoidance of good quality habitat in proximity of industrial infrastructures," said Weclaw, lead author of the study, which will be published this month in Ecological Modelling.
A previous study conducted through the Boreal Caribou Committee, a group of U of A researchers dedicated to studying caribou, showed caribou will generally stay about 200 metres clear of any human industrial developments, including roads and seismic lines.
Weclaw added that some measures are being taken to reduce the impact humans are having on Alberta's northern boreal land. For one, he said, seismic lines, which oil and gas exploration companies make to produce a model of subsurface geological structures, are being made narrower than they used to be and are no longer cut in straight lines. The lines are also reseeded shortly after being cut. Research is being conducted to see if these measures lessen the impact on the caribou.
However, whether these measures prove effective or not, Weclaw believes that even more needs to be done to ensure the continued survival of the caribou in northern Alberta.
"We need to get all interested parties together to work on solutions to protect the caribou. Our research suggests that if things continue as they are now, soon we won't have anymore caribou to protect," he said.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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