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Canada lynx are persisting in spruce-beetle impacted forests

Date: August 25, 2016

Bark beetles impacted about 480,000 acres of spruce-fir forests in southern Colorado and are spreading at the rate of 100,000 acres annually


Background

Jake Ivan (CO Parks & Wildlife) and technicians instrumenting an anesthetized Canada lynx.   (Photo - UpperRGFemale_Handling)
Jake Ivan (CO Parks & Wildlife) and technicians instrumenting an anesthetized Canada lynx
The Rio Grande National Forest (RGNF) includes some of the most important Canada lynx habitat in Colorado. Approximately 85 percent of the 218 lynx reintroduced to Colorado from 1999-2007 were released on the RGNF. Lynx depend on spruce-fir forests with dense understories across their distribution.  However, by 2013, a spruce beetle outbreak killed approximately 85 percent of mature spruce in the subalpine cover types on the RGNF, and these impacts will be more prevalent in the future with climate change. Biologists are in the difficult position of being required to evaluate the impact of timber salvage to this federally-listed species without a scientific basis to support their decisions. 

The Rocky Mountain Research Station, in cooperation with the RGNF, the USFS Rocky Mountain Region, Colorado Parks and Wildlife, and Montana State University, is currently investigating the resource selection and movements of Canada lynx that occupy spruce-beetle impacted forests. The project's objectives include:

1) determine seasonal changes in resource-use of Canada lynx in spruce beetle-impacted forests of southern Colorado;

2) map forest characteristics across spruce-beetle impacted landscapes relative to proposed timber salvage; and

3) document the relative abundance of snowshoe hares, the primary prey of lynx, in relation to forest structures found in spruce-beetle outbreaks.

Spruce-beetle mortality in lynx home range with live understory (Photo -  Spruce-mortality_lynx homerange)
Spruce-beetle mortality in lynx habitat
In 2015-2016, the team instrumented lynx with GPS collars to plot their movements and resource-use patterns in beetle-impacted forests. Using this technology ,the team documented that lynx used spruce-beetle impacted forests during winter and summer, including females that denned and produced kittens. Using remote sensing and by sampling more than 450 vegetation plots, the research partners have mapped the forest overstory and understory of beetle-impacted forests. To develop stand-level silvicultural prescriptions, the team is currently sampling forest attributes at GPS locations and random sites to understand lynx habitat selection in beetle-impacted forests.

This research will inform stand and landscape-level silvicultural prescriptions relative to proposed timber salvage in relation to lynx conservation. This issue is highly relevant across the West as insect-impacts to forests will increase with climate change.

 

Key Findings

  • Lynx used spruce-beetle impacted forests during winter and summer, including females that denned and produced kittens.


Principal Investigators: 
Forest Service Partners: 
Randy Ghormley, Rio Grande National Forest, Colorado
Scott Jackson, USFS National Carnivore Program Lead
External Partners: 
Jake Ivan, Co-investigator, Colorado Parks and Wildlife
Rick Lawrence, Co-investigator, Montana State University
Research Location: 
Rio Grande National Forest, San Juan Mountains, southern Colorado