(Edmonton) The work of a U of A graduate student exploring synergies among such scavengers as bears, wolves and ravens may help conservationists determine which species are most at risk of local extinction, and why.
Kim Ives, who just earned a master's degree from the Department of Renewable Resources, explored regional patterns and causes of local extinctions-in which a species disappears from a region-for North American mammals and birds that depend on scavenging their meals.
Her findings indicate that co-operative relationships among the animals is an important contributing factor to patterns of extinction. This, in turn, provides an additional tool to help conservationists determine which species are at risk of being lost from the ecosystem, she said.
While human impact and ecological traits are already accepted as contributing factors to extinction risk, the idea that behavioural interactions among species, in which the actions of one species can influence the survival of others, has rarely been considered.
"Yet, it is fundamental to predicting risk of species, such as scavengers who rely on other members of the community-particularly predators-for providing food," Ives said.
The research, supervised by Scott Nielsen, professor of renewable resources, was conducted under the auspices of the Applied Conservation Ecology Lab at the U of A. Ives' findings are among the first to touch on animal behavioural interactions as they relate to conservation risk. Ives believes a more holistic approach will better gauge that risk.
"By not accounting for these interactions in our analyses of conservation risk, it could be a major hole to leave open," said Ives, who studied just how much the animals rely on one another's scavenging habits to survive.
Loss of behavioural interactions among species may be a contributing factor to why some are more vulnerable to extinction than others: "Scavengers have indirect but critical links."
For instance, otters pull fish from the river to shore for other scavengers to find. As well, ravens follow wolves to their kills, and because the birds are known to eat a lot of the carcass, wolves kill more.
Using statistical modelling, Ives determined that ravens had the highest number of connections, to 20 other species, followed by the black bear and the otter.
If any of the species suffer population loss, the survival of connected scavengers could also be threatened, Ives said. She hopes her findings will lead to richer approaches in conservation measures, including a closer look at dependencies among different animals.
"Successful reintroduction of an extirpated species may be more effective if other interacting species are included at the same time."
Ives' work was supported by funding from the Natural Sciences and Engineering Research Council of Canada, TD Friends of the Environment Foundation and the University of Alberta's Queen Elizabeth II Graduate Scholarship.