In the first published results of more than three years of tracking pumas (or mountain lions) in the Santa Cruz Mountains, researchers of University of California Santa Cruz (UCSC) document how human development affects the predators’ habits.
In their findings published on 17 April in the open access journal PLOS ONE, UCSC associate professor of environmental studies Chris Wilmers and colleagues with the UC Santa Cruz Puma Project describe tracking 20 pumas (Puma concolor) over 17,000 square kilometres for three years. Researchers are trying to understand how habitat fragmentation influences the physiology, behaviour, ecology, and conservation of pumas in the Santa Cruz Mountains.
The large predators living relatively close to a metropolitan area require a buffer from human development at least four times larger for reproductive behaviours than for other activities such as moving and feeding.
“In addition, pumas give a wider berth to types of human development that provide a more consistent source of human interface,” such as neighbourhoods, than they do in places where human presence is more intermittent, as with major roads or highways, the authors write.
37 pumas captured
Wilmers and his team, which includes graduate students, and a dog tracking team working with the California Department of Fish and Wildlife, have captured 37 pumas to date. Twenty – 12 females and eight males – were closely followed between 2008 and 2011. Once captured and anaesthetised, the pumas’ sex was determined, they were weighed, measured, fit with an ear tag and a collar with a GPS transmitter. The collars, developed, in part, by an interdisciplinary team at UCSC, including wildlife biologists and engineers, transmit location data every four hours.
Researchers are able to track the pumas’ movements and calculate locations of feeding sites, communication spots, and dens. Pumas communicate with scent markings known as “scrapes” where they scrape leaves or duff into a pile then urinate on it. Males typically make the scrapes, advertising their presence and availability. Females visit scrapes when looking for mates.
Video belows shows lion 16M scraping:
The Puma Project team set up and monitored remote cameras at 44 scrape locations and documented males and females, which confirmed GPS data from the pumas’ collars. Researchers also found 10 den sites belonging to 10 different female lions. They visited 224 “GPS clusters” where activities suggested a feeding site, and located prey remains at 115 sites.
Wilmers said the research is helping identify corridors where pumas typically travel between areas of high-quality habitat. This includes neighbourhoods where females often are willing to explore for food for their fast-growing brood.
Brushes with humans
Brushes with humans have resulted in casualties when pumas were struck by cars or caught raiding livestock. One male known as 16M was shown to have crossed busy Highway 17 between Scotts Valley and Los Gatos 31 times. He was hit and badly injured in November 2010 and recently shot and killed after attacking goats. A female, 18F, who may have been 16M’s mate, was killed in 2011 crossing the winding highway.
Eight of the 11 pumas that died during the study were killed when caught attacking domestic livestock. Wilmers advised owners of goats or other livestock to consider keeping them in a “fully-enclosed puma-proof structure.”
The study’s conservation goals are meant to help pumas survive in the midst of rapidly growing human development by building awareness of pumas’ behaviour and providing safe transit opportunities under or over major highways.
(Source: UCSC press release, 17.04.2013)