Watching the World’s Smallest Rabbit, and Lynx Extirpation in Wyoming
Pygmy rabbits in Wyoming may soon gain federal protection, while Wyoming's lynx population is functionally extinct.
After a recent snow, I took a walk out through the sagebrush to see what animal tracks I could find and soon discovered numerous pygmy rabbit tracks and trails that eventually led to their burrows. This finding wasn’t unexpected, as I’ve seen numerous pygmy rabbits on early morning jaunts in this region throughout the year. I set up a game camera in the sagebrush and recorded a few short videos of a pygmy rabbit the next morning.
In early 2024, the U.S. Fish & Wildlife Service determined that the pygmy rabbit may warrant protection under the Endangered Species Act and is set to release its 12-month status review findings soon. (The genetically distinct pygmy rabbits in Washington’s Columbia Basin are already classified as an endangered species.)
Western Wyoming serves as the eastern-most extent of the pygmy rabbit’s range. It wasn’t until 1981 that pygmy rabbits were ever confirmed to occur in Wyoming (first in the Carter area of Uinta County, and in the Cumberland Flats area of Lincoln and Uinta counties).
Although the advocacy groups that petitioned to have pygmy rabbits federally protected (led by the anti-livestock Western Watersheds Project) claimed that livestock grazing is a primary threat to pygmy rabbits, when FWS declined to list pygmy rabbits back in 2010 the agency noted:
“Our review of the best available scientific data indicates that measurable population decreases attributed to habitat modifications from livestock grazing are not occurring across the range. Therefore, we conclude that livestock grazing is not a significant threat to the pygmy rabbit now or in the foreseeable future.”
While the pygmy rabbit may indeed be in decline, it appears to have been on a downward slope for more than 7,000 years as the climate and vegetative communities changed. The species has a highly patchy distribution throughout their geographic range, with researchers noting that some gaps in occupancy coincide with the presence of Pleistocene lakes. They noted, “The distributions of both sagebrush and occurrences of pygmy rabbits appear to be negatively correlated with the distribution of these prehistoric lakes, possibly due to climatic changes in the middle Holocene that altered vegetative communities and potentially soil characteristics in these basins.”
But relatively little is known about the pygmy rabbit, its current occupied range, or its population status. The Wyoming Game & Fish Department is slated to undertake major survey efforts next year, and we’ll look forward to those results.
What we do know is that Wyoming has greatest estimated occupied area of any state (about 5,300 square miles), with most known pygmy rabbit occurrences overlapping with the distribution of sage grouse.
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While anti-grazing groups use pygmy rabbits as a ploy in their attempt to rid public land of livestock, the greatest threat to pygmy rabbit persistence is greater wildfire frequencies causing habitat loss. Livestock grazing, and treatment of invasive species like cheatgrass, help to reduce the risk of catastrophic wildfires that would decimate pygmy rabbits.
It's also worth noting that predation is the highest cause of pygmy rabbit mortality, accounting for nearly 90% of all pygmy rabbit deaths in one study, with coyotes responsible for most losses to predators, followed by avian predators and weasels.
It’s no wonder that the pygmy rabbits I’ve recently encountered occur in areas where there is livestock grazing with livestock guardian dogs (which help to deter predators), as well as targeted predator control (not an eradication program). With less predator pressure, livestock producers can produce more lambs (or pounds of lamb) per ewe in addition to providing suitable habitat for species like pygmy rabbits and swift fox. I look at the presence of these species as a success we should celebrate, and hope that we are not punished by federal intervention for providing safe havens for these species.
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Lynx are Functionally Extinct in Wyoming
In other endangered species news, the U.S. Fish & Wildlife Service (FWS) is reducing the amount of critical habitat for Canada Lynx in the Greater Yellowstone Area (GYA) of Wyoming by 8,000 square miles. That’s because the lynx population in this region is functionally extirpated, even though lynx may be recorded every now and then.
According to FWS, lynx populations estimated at fewer than 25 individual lynx are considered ‘‘not resilient/functionally extirpated’’ because populations that small are unlikely to persist over time. That’s essentially how lynx in the GYA are classified.
There are two things that lynx must have to survive: abundant snowshoe hare populations, and deep and persistent “fluffy” snow conditions that limit other predators but enables the lynx to successfully hunt its prey. According to FWS, “Recent habitat modeling that is foundational to this critical habitat revision demonstrated that most of the GYA, including areas previously designated as lynx critical habitat, does not contain the physical and biological features necessary to support persistent lynx residency.”
Here's a side-by-side comparison of the 2014 map of critical habitat with the 2024 proposal.
Most of the critical habitat for lynx in Wyoming will remain in the Wyoming Range of the Bridger-Teton National Forest, but this area has a slim chance of ever harboring a breeding lynx population. According to FWS, “It is uncertain whether this unit historically supported a small resident population or if lynx presence and reproduction were and are naturally ephemeral and intermittent. The area currently does not appear to support a resident breeding population.”
Still, the Wyoming Range reportedly has “small pockets of habitat on the Bridger-Teton National Forest in the southern part of the GYA supporting high hare densities.”
FWS estimates that the GYA could potentially support a population of 25–50 lynx “if sufficient habitat conditions and hare densities could be achieved and maintained, and a resident lynx population is established via translocation.” But the plan doesn’t anticipate undertaking a translocation either. Instead, the plan tries to conserve potential refugia habitat to preserve the future opportunity to do so if necessary to prevent extirpation of lynx in the Lower 48.
Recovery Strategy
The revised lynx recovery plan released last week notes that lynx populations in the United States seem to function as subpopulations or southern extensions of larger populations in southern Canada. The greatest threat to the species is global climate change, according to FWS, which threatens the long-term conservation of lynx as well as their boreal forest habitats.
The recovery plan focuses on retaining most existing lynx habitat, calling for no more than a 5% loss of habitat in a 20-year period. “The 5-percent threshold for permanent reductions in lynx habitat applies to anthropogenic changes to the habitat that convert it to nonforest or convert boreal forest to another vegetation type that does not provide lynx habitat.”
The plan has 6 focal areas, including the GYA, but the GYA is the only focal area that lacks a breeding population of lynx and has no population objective to achieve recovery. The other focal areas with lynx production are: northern Maine and northeastern New Hampshire; northeastern Minnesota; northwestern Montana and northern Idaho; and southwestern Colorado.
According to FWS, “The Canada lynx is believed to have evolved from the Eurasian lynx in the last 200,000 years in North America as a snowshoe hare specialist,” but with this narrow and specialized ecological niche, lynx “likely have little ability to adapt to changing environmental conditions.”
“All aspects of lynx life history are inextricably tied to the snowshoe hare, which comprises most of the lynx diet throughout its range,” the agency reports.
Forest Management Threats
Comments by professional peer reviewers of the plan noted that forest management remains an important issue for the future of this species. One reviewer noted “without intentional forest management, we could stand to lose more lynx habitat to fire than to the fuels treatments themselves” and “Large, high severity wildfires pose a risk to lynx not only as a temporary loss of habitat, but because they can accelerate forest conversion under climate change, perhaps permanently altering areas to non-habitat.” He also advised that “reducing the risk of catastrophic habitat loss to wildfires may be better served by informed, intentional, and strategic fuels reduction. This versus business as usual or managing for increased mature forests.”
Another reviewer stated: “Climate change has altered fire disturbance outside the range of natural variability (>1000 yr time frames). Spruce-fir forests that lynx / hares require are especially at risk. We are in completely different times in terms of fire frequency and severity to the point that some forested landscapes in the subalpine zone will not recover to forests at all - forest to meadow.”
Being highly specialized hare predators, lynx require landscapes that consistently support relatively high hare densities. Snowshoe hares feed on conifers, deciduous trees, and shrubs and are most abundant in forests with dense understories that provide forage, cover to escape from predators, and protection during extreme weather.
The recovery plan lays out a 20-year path for lynx recovery, and emphasizes the need for intentional, proactive forest management to reduce the likelihood of catastrophic wildfires and insect outbreaks in lynx habitats.
To read the recovery plan, go here, or click here for the lynx critical habitat proposal.
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