A lynx prowls through thick snow with trees in the background. USDA Forest Service Rocky Mountain Research Station-Canada Lynx of the Rockies Research Program. Credit: John Squires USDA Forest Service Rocky Mountain Research Station-Canada Lynx of the Rockies Research Program. Public Domain.
Protected areas provide suitable habitats for the threatened Canadian lynx, but an increase in wildfires poses additional risks for the rare cat.
New research suggests future wildfires may be the greatest threat to lynx habitat in the southern Rocky Mountains.
Canada lynx are specialised hunters, able to travel in deep snow and spot prey in the darkness from 250 feet away.
Keen hearing and vision make them excellent trackers, but what do we learn by turning the tables and tracking them?
Scientists are using GPS data and advanced modelling to refine maps and identify important habitat characteristics, particularly in the forests of western Colorado, southern Wyoming, and northern New Mexico, the southernmost extent of its range.
New research and updated maps show that more than half of lynx habitat in the southern Rocky Mountains overlaps protected areas like wilderness and national parks.
The maps also show that lynx habitat is sparse, patchy, and poorly connected, existing only in narrow bands due to Colorado’s complex mountainous terrain.
These maps can identify corridors where habitat loss affects animal movement, which is important for healthy populations.
Updated maps help managers focus conservation efforts and pinpoint places to promote new habitat, especially given the frequency of human development, fire, and forest insect outbreaks near the edges of lynx range.
Re-introduction
Lynx in the western US prefer high-elevation spruce-fir forests with tree branches hanging close to the snow or ground surface, providing dense horizontal cover.
This forest structure supports the cat’s favourite prey, snowshoe hares, which can make up 90% of their diet in winter.
Lynx were reintroduced to the southern Rockies over two decades ago after populations had fallen below a self-sustaining level. Several generations of females and kittens have successfully established here, allowing these populations to bounce back.
Researchers used GPS collars to track lynx within the study area, focused on the southern extent of its range.
They also considered over 40 habitat or environmental characteristics, such as the amount of precipitation as snow versus rain, the month with the coldest temperature, road density, vegetation, and slope position.
Combining GPS and habitat data and using state-of-the-art statistical tools and modelling methods, these scientists identified which characteristics best predicted where lynx were found and used this information to map ‘likely’ lynx habitat where cats have a high probability of living, breeding, and successfully raising young.
Then they took this information one step further, comparing ‘likely’ habitat with disturbances like insect outbreaks, wildfire, timber harvest, or human-footprint impacts such as urbanisation or ski resorts.
The scientists found that around one-third of likely habitat overlapped with disturbance, including forest insect outbreaks (31%), wildfire (5%), and forest management activities like tree harvest and prescribed burning (3%).
Despite the greater overlap of lynx habitat with insect outbreaks, the scientists are more concerned by the impacts of severe wildfires.
High-severity wildfire
Dr John Squires, the study’s principal investigator and a Rocky Mountain Research Station research wildlife biologist, said: “We know that lynx continue to occupy areas after insects kill the overstory trees during spruce-beetle outbreaks.
“Forests impacted by spruce beetles still have enough young conifer trees in the understory to support hares.
“Also, some tree species like subalpine fir often survive spruce beetle attacks. That means that forest insects represent a more benign threat to lynx compared to broad-scale, high-severity wildfire.”
The researchers found that lynx tend to avoid fire-impacted areas until the understory has regrown–a process that takes upwards of 50 years in subalpine forests in the southern Rockies, where fires tend to burn less frequently than lower elevation forests and are often stand-replacing.
Squires said: “Although fire disturbance from 1990-2022 overlapped only 5% of likely lynx habitat in this area, we believe that frequent, high-severity fire is the main risk to lynx in high-elevation forests moving forward.”
Study co-author Dr Lucretia Olson, a Rocky Mountain Research Station ecologist, said: “We were surprised at how little lynx habitat overlapped areas of managed forest and human development.
“While forest management mainly causes temporary habitat changes, activities like urbanisation and developing or expanding ski areas often lead to permanent losses.
“We hope our work will reach managers who make complex decisions about land uses.”
Squires stressed the value of partnerships for conducting this research: “Close collaboration across state and federal agencies in terms of data sharing, logistical support, and added expertise made this research possible.”
The study is published in Biodiversity and Conservation.
