While many of you likely are familiar with one of America's foremost Cougar biologists, I just recently stumbled across Paul Beier's body of work on Cougars and wildlife corridors. Paul currently works out of The University of Northern Arizona and you can access his website by "punching in" Paul Beier on Google.
Over the weeks ahead, we will dive deeper into Paul's work with tonight my focus on his 1988-92 conclusions on the minimum habitat needed for Cougars to persist for 100 years(ignoring the consequences of inbreeding effects of that persisting population) in a given habitat. His location of study for this investigation was the Santa Ana Mountains of Orange County, California...............just south of Los Angeles in one of the most densely human populated regions of the USA.
Some Cougar facts from this study include that up to 40% of 2 year old female Cougars breed each year(yearlings do not breed). Survival of Cougar cubs in their first year is suggested at 0.48(just less than half). Lifespan for Cougars tends to max out at 12 years in the wild with adult survival rates annually at somewhere between 65 to 85% of a given population. While not strictly territorial, social intolerance among females is thought to regulate their density whereas territoriality does determine male cougar density. Female density is calibrated to prey availability and and topography whereas males compete for access to females.
A 2 female to 1 male ratio per 100 square km with about a 0.95 adults per 100 square km is thought to be typical carrying capacity. Gestation period is 92 days for kittens.
With an estimated 2+million human animals living in the Eastern half of Orange County and Western 1/6 of Riverside County in California, Paul estimated that a 98% probability existed for a 1000- 2200 square km of contiguous and viable Cougar habitat to support about 20 adult Cougars for 100 years. This acreage will not guarantee long term survival. If a wildlife corridor is available to this sanctuary allowing up to three males and one female per decade, the extinction risk is greatly lowered along with inbreeding.
The attached paper is detailed and dense(in a good way) with statistics and tables qualifying Paul's revelations. Look forward to investigating his work further and posing questions periodically. Enjoy the read!
Blogger Rick in a thoroughly warm(80 degrees--normal for early May is 68 degrees) New York City reporting.
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