Habitat occupancy assessment to help monitor status of population
By Bob Berwyn
SUMMIT COUNTY — Colorado Parks and Wildlife biologists say they’re close to finalizing a plan to monitor the state’s lynx population by assessing habitat occupancy. If successful, the strategy would enable researchers to determine whether the population of endangered wild cats is sustaining itself over time.
The habitat occupancy model was tested in a pilot program in core lynx habitat in the San Juans a couple of years ago, showing that about 50 to 60 percent of the available lynx habitat is occupied. Now the biologists are trying to figure out if they can use the same method to keep tabs on lynx across the entire state.
Lynx have been listed as a threatened species since 2000, with a population in New Mexico currently under consideration for listing as a candidate species. Colorado launched a restoration program in 1999, transplanting more than 200 lynx from Canada and Alaska to the San Juans.
The reintroduction effort was declared a success about two years ago, after 10 years of intensive monitoring, with on-the ground visits to lynx dens, as well as tracking via airplanes and satellites. The tracking shows that the population has spread northward, with resident, breeding lynx up through the Collegiate Range and even into Summit County, with pockets of populations north of I-70.
In a draft report on the pilot study, biologists said it’s not feasible to accurately estimate population numbers, but assessing habitat use and occupancy can help determine whether the population is stable, growing or declining — and might also show trends in habitat use, for example in response to changing forest conditions. Colorado Parks and Wildlife lynx research is online here. Continue reading “Colorado biologists planning statewide lynx assessment”→
State wildlife agency testing new method for monitoring wild carnivore populations on a landscape scale
By Bob Berwyn
SUMMIT COUNTY — If you’ve been waiting for the 2011 spring lynx kitten count from the Colorado Division of Parks and Wildlife, don’t hold your breath. Instead if visiting individual dens to collar and count lynx, state biologists are shifting gears, working to determine whether the wild cats can hold their own in Colorado in the long run with an unprecedented habitat occupancy model.
Intensive monitoring during the first 10 years of the state lynx recovery program included annual visits to lynx dens, as well as aerial and satellite monitoring. The research yielded detailed information about lynx behavior and reproduction, including annual reports that specified the number of new kittens as a way of measuring reproductive success. The 2009-2010 annual lynx program report is online here.
But this year, state biologists are switching to a new mode of tracking the rare mountain wild cats. Using a network of motion-activated cameras, snow tracking and genetic sampling, the researchers hope to determine where the cats are living, eating and sleeping, and how well they are filling all the available habitat in the state. An overall assessment of the Colorado lynx recovery program is online here.
The data from those sources will help document the distribution and persistence of lynx across the landscape, said biologist Tanya Shenk, who led the Colorado recovery effort in its first 10 years and now works for the National Park Service as a climate change and landscape ecologist. Shenk said there has been a general move by wildlife and conservation biologists to move away from invasive techniques that put a lot of stress on individual animals. The Colorado Division of Parks and Wildlife lynx program information is online here. Continue reading “Colorado: Will the lynx survive?”→