Thursday, March 6, 2014

Cougars Are Re-Populating their Historical Range

American mountain lions, or cougars, are remerging in areas of the United States, reversing 100 years of decline. The evidence, published in The Journal of Wildlife Management, raises new conservation questions, such as how humans can live alongside the returning predators.

The reintroduction of mountain lions across the mid-western United States has made species management an urgent area of research for conservationists. A report in the Wildlife Society Bulletin explores the fatal cost of human interaction with cougars and asks what state agencies can do to protect both species.

Cougars (Puma concolor) are slowly recolonizing their historic habitats, including the Black Hills of South Dakota, but since they’ve been away, the land has become crossed with roads and home to many human communities.

The authors studied 31 cougars, captured between 1999 and 2005. Over the course of 1,570 days, 12 mortalities were recorded. Despite being protected from hunting nearly 62% of cougar deaths were attributed to human influences.

A further 85 dead cougars were analyzed during the study, with collisions being the most common cause of death. Snaring and illegal hunting were also identified as causes.

“The cougar population declined dramatically from 1900, due to both hunting, and a lack of prey, leaving the remaining population isolated to the American west,” said Michelle LaRue from the University of Minnesota. “Here we present the hard evidence that the western population has spread, with cougar populations re-establishing across the Midwest.”

Three main cougar populations exist in the Midwest centered around The Black Hills in South Dakota, however, cougars are venturing far outside of this range. One male cougar from the Black Hills was found to have traveled 2,900 kilometers through Minnesota, Wisconsin and New York, before ending up in Connecticut.

“While the distance the Connecticut cougar traveled was rare, we found that cougars are roaming long distances and are moving back into portions of their historical range across the Midwest ”, said LaRue. “Our study took in over 3,200,000 Km² of territory, confirming the presence of Cougars from Texas, Arkansas and Nebraska, to the Canadian provinces of Ontario and Manitoba.”

Working alongside scientists from Southern Illinois University Carbondale and The Cougar Network, LaRue and Principal Investigator Dr. Clay Nielsen analyzed cougar sightings which have been reported since the 1990’s to characterize confirmed sightings over time, assess habitat suitability and confirm where cougar populations are being re-established.

Aside from confirmed sightings, the team’s evidence included carcasses, tracks, photos, video, DNA evidence and cases of attacks on livestock across 14 states and provinces of North America. Only sightings which were verified by wildlife professionals were included, while sightings of animals known to be released from captivity were excluded to ensure only natural repopulation was analyzed.

The results reveal 178 cougar confirmations in the Midwest with the number of confirmations steadily increasing between 1990 and 2008. Approximately 62% of confirmed sightings took place within 20km of habitat that would be considered suitable for cougar populations.

When cougar carcasses were recovered 76% were found to be male. As the Connecticut example shows, males are capable of traveling long distances and this finding suggests males are leading a stepping-stone dispersal of the cougar population.

“This evidence helps to confirm that cougars are re-colonizing their historical range and reveals that sightings have increased over the past two decades,” concluded LaRue. “The question now is how the public will respond after living without large carnivores for a century. We believe public awareness campaigns and conservation strategies are required across these states, such as the Mountain Lion response plans already in place in Nebraska and Missouri.”

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