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The article provides a taxonomic description of the genus Brachylagus, which includes small-sized rabbits known as pygmy rabbits. The genus consists of a single recognized species, Brachylagus idahoensis, with some regional variations in populations. The pygmy rabbits are adapted to the sagebrush ecosystems of western North America and exhibit unique characteristics such as small size, variable fur coloration, large ears, and short tails. Conservation efforts are being made to protect their habitats and ensure their survival in the face of environmental challenges caused by human activities. [Extracted from the article]

Local adaptation can occur when spatially separated populations are subjected to contrasting environmental conditions. Historically, understanding the genetic basis of adaptation has been difficult, but increased availability of genome‐wide markers facilitates studies of local adaptation in non‐model organisms of conservation concern. The pygmy rabbit (Brachylagus idahoensis) is an imperiled lagomorph that relies on sagebrush for forage and cover. This reliance has led to widespread population declines following reductions in the distribution of sagebrush, leading to geographic separation between populations. In this study, we used >20,000 single nucleotide polymorphisms, genotype‐environment association methods, and demographic modeling to examine neutral genetic variation and local adaptation in the pygmy rabbit in Nevada and California. We identified 308 loci as outliers, many of which had functional annotations related to metabolism of plant secondary compounds. Likewise, patterns of spatial variation in outlier loci were correlated with landscape and climatic variables including proximity to streams, sagebrush cover, and precipitation. We found that populations in the Mono Basin of California probably diverged from other Great Basin populations during late Pleistocene climate oscillations, and that this region is adaptively differentiated from other regions in the southern Great Basin despite limited gene flow and low effective population size. Our results demonstrate that peripherally isolated populations can maintain adaptive divergence. [ABSTRACT FROM AUTHOR]

Abstract Sagebrush ecosystems are affected by a variety of factors, and loss and degradation of sagebrush habitat threatens many wildlife species. Federal land management and wildlife agencies have invoked the umbrella species concept to protect this ecosystem, designating >580,000 km2 as Habitat Management Areas (HMAs) for greater sage‐grouse (Centrocercus urophasianus; hereafter “sage‐grouse”) putatively benefiting multiple wildlife species. The pygmy rabbit (Brachylagus idahoensis) also is a species of conservation concern due to its obligate relationship with the sagebrush ecosystem, and our goal was to evaluate the degree to which grouse‐focused HMAs might serve as a conservation umbrella for pygmy rabbit habitat. We acquired 18,598 records of pygmy rabbit occurrence from all eight range states (excluding Washington because that population is undergoing reintroduction); after screening for reliability, we retained 10,420 records, which we used to estimate minimum occupied area (MOA) and to create an inductive species distribution model (SDM) for pygmy rabbits across their full geographic range. We used the program Maxent to build models of varying complexity, incorporating topographic, vegetation, fire, climate, and soil information. The pygmy rabbit MOA is estimated at 28,367 km2, and ~92% of this area is included within sage‐grouse HMAs. We identified 224,820 km2 of suitable habitat for pygmy rabbits (maximum test sensitivity plus specificity threshold of 0.3167) and 145,725 km2 of primary habitat (equal test sensitivity and specificity threshold 0.4661), with concentrations in four distinct core areas. Overlap with sage‐grouse HMAs was high (87% of suitable habitat and 91% of primary habitat), suggesting that the sage‐grouse umbrella has the potential to conserve habitat for pygmy rabbits. Two of the largest HMAs are Priority Habitat Management Areas (PHMAs; which have the most habitat protection) and General Habitat Management Areas (GHMAs; which have less protection). Our results suggest that PHMAs encompass 59% and GHMAs encompass of 34% of primary habitat for pygmy rabbits. The SDM of habitat for pygmy rabbits can be used by land managers and biologists to prioritize survey locations for pygmy rabbits and to identify areas for habitat management, conservation, or restoration.

Sagebrush ecosystems are affected by a variety of factors, and loss and degradation of sagebrush habitat threatens many wildlife species. Federal land management and wildlife agencies have invoked the umbrella species concept to protect this ecosystem, designating >580,000 km² as Habitat Management Areas (HMAs) for greater sage-grouse (Centrocercus urophasianus; hereafter “sage-grouse”) putatively benefiting multiple wildlife species. The pygmy rabbit (Brachylagus idahoensis) also is a species of conservation concern due to its obligate relationship with the sagebrush ecosystem, and our goal was to evaluate the degree to which grouse-focused HMAs might serve as a conservation umbrella for pygmy rabbit habitat. We acquired 18,598 records of pygmy rabbit occurrence from all eight range states (excluding Washington because that population is undergoing reintroduction); after screening for reliability, we retained 10,420 records, which we used to estimate minimum occupied area (MOA) and to create an inductive species distribution model (SDM) for pygmy rabbits across their full geographic range. We used the program Maxent to build models of varying complexity, incorporating topographic, vegetation, fire, climate, and soil information. The pygmy rabbit MOA is estimated at 28,367 km², and ~92% of this area is included within sage-grouse HMAs. We identified 224,820 km² of suitable habitat for pygmy rabbits (maximum test sensitivity plus specificity threshold of 0.3167) and 145,725 km² of primary habitat (equal test sensitivity and specificity threshold 0.4661), with concentrations in four distinct core areas. Overlap with sage-grouse HMAs was high (87% of suitable habitat and 91% of primary habitat), suggesting that the sage-grouse umbrella has the potential to conserve habitat for pygmy rabbits. Two of the largest HMAs are Priority Habitat Management Areas (PHMAs; which have the most habitat protection) and General Habitat Management Areas (GHMAs; which have less protection). Our results suggest that PHMAs encompass 59% and GHMAs encompass of 34% of primary habitat for pygmy rabbits. The SDM of habitat for pygmy rabbits can be used by land managers and biologists to prioritize survey locations for pygmy rabbits and to identify areas for habitat management, conservation, or restoration. [ABSTRACT FROM AUTHOR]

ABSTRACT We used both experimental and observational approaches to investigate sub‐lethal effects of capture and radiocollaring on pygmy rabbits (Brachylagus idahoensis) in Idaho and Washington during 2004–2008. We expected that attachment of collars would increase rates of grooming behaviors and alter patterns of space use. Frequency of grooming was >3 times higher following attachment of radiocollars on captive rabbits; however, the grooming rate declined rapidly and returned to within 5% of pre‐collaring levels after 7 days. Free‐ranging rabbits exhibited relatively longer distance movements immediately following and during the 2 weeks after capture and attachment of radiocollars, but those movements decreased during weeks 3–4 post‐collaring. Rabbits also shifted use areas away from capture locations. Our results suggest that: 1) rabbits became habituated to the presence of collars with respect to grooming; and 2) although, magnitude of movements following capture and collaring in the field attenuated with time, some animals continued to avoid capture areas up to 4 weeks after collaring. A better understanding of potential effects of telemetry on wildlife can help to improve the quality of data collected, design ways to mitigate the impacts on animals, and enhance the ethical conduct of wildlife research. © 2014 The Wildlife Society.

ABSTRACT We used both experimental and observational approaches to investigate sub-lethal effects of capture and radiocollaring on pygmy rabbits ( Brachylagus idahoensis) in Idaho and Washington during 2004-2008. We expected that attachment of collars would increase rates of grooming behaviors and alter patterns of space use. Frequency of grooming was >3 times higher following attachment of radiocollars on captive rabbits; however, the grooming rate declined rapidly and returned to within 5% of pre-collaring levels after 7 days. Free-ranging rabbits exhibited relatively longer distance movements immediately following and during the 2 weeks after capture and attachment of radiocollars, but those movements decreased during weeks 3-4 post-collaring. Rabbits also shifted use areas away from capture locations. Our results suggest that: 1) rabbits became habituated to the presence of collars with respect to grooming; and 2) although, magnitude of movements following capture and collaring in the field attenuated with time, some animals continued to avoid capture areas up to 4 weeks after collaring. A better understanding of potential effects of telemetry on wildlife can help to improve the quality of data collected, design ways to mitigate the impacts on animals, and enhance the ethical conduct of wildlife research. © 2014 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Pygmy rabbits ( Brachylagus idahoensis) are one of only three vertebrates that subsist virtually exclusively on sagebrush ( Artemisia spp.), which contains high levels of monoterpenes that can be toxic. We examined the mechanisms used by specialist pygmy rabbits to eliminate 1,8-cineole, a monoterpene of sagebrush, and compared them with those of cottontail rabbits ( Sylvilagus nuttalli), a generalist herbivore. Rabbits were offered food pellets with increasing concentrations of cineole, and we measured voluntary intake and excretion of cineole metabolites in feces and urine. We expected pygmy rabbits to consume more, but excrete cineole more rapidly by using less-energetically expensive methods of detoxification than cottontails. Pygmy rabbits consumed 3-5 times more cineole than cottontails relative to their metabolic body mass, and excreted up to 2 times more cineole metabolites in their urine than did cottontails. Urinary metabolites excreted by pygmy rabbits were 20 % more highly-oxidized and 6 times less-conjugated than those of cottontails. Twenty percent of all cineole metabolites recovered from pygmy rabbits were in feces, whereas cottontails did not excrete fecal metabolites. When compared to other mammals that consume cineole, pygmy rabbits voluntarily consumed more, and excreted more cineole metabolites in feces, but they excreted less oxidized and more conjugated cineole metabolites in urine. Pygmy rabbits seem to have a greater capacity to minimize systemic exposure to cineole than do cottontails, and other cineole-consumers, by minimizing absorption and maximizing detoxification of ingested cineole. However, mechanisms that lower systemic exposure to cineole may come with a higher energetic cost in pygmy rabbits than in other mammalian herbivores. [ABSTRACT FROM AUTHOR]

Dramatic declines in the endangered Columbia Basin pygmy rabbit, a genetically unique population of small, burrowing rabbits in Northwestern United States, are likely the combined results of habitat degradation and fragmentation, disease, and predation. A critical component of pygmy rabbit habitat includes big sagebrush (Artemisia tridentata), which constitutes 82–99% of their winter diet and 10–50% of their summer diet. Sagebrush also forms the bulk of hiding cover around burrow sites. Across the range of pygmy rabbits, sagebrush habitat is grazed extensively by cattle. However, grazing has unknown effects on pygmy rabbits inhabiting the remaining, fragmented shrub-steppe habitat. We evaluated the effects of four grazing treatments on the distribution of pygmy rabbit burrows, diets of pygmy rabbits, and quality and quantity of vegetation at Sagebrush Flat in central Washington. Ungrazed areas contained significantly more burrows per unit area than did grazed areas. Vegetation composition and structure differed little among treatments in early summer before annual grazing by cattle. However, cattle grazing in late summer through winter removed about 50% of the grass cover, and reduced the nutritional quality (e.g., increased fiber and decreased protein) of the remaining grass. Although pygmy rabbits ate <2% grasses in winter, grasses and forbs comprised 53% of late summer diets. Because these endangered rabbits avoided grazed areas, removing cattle grazing from key habitat locations may benefit efforts to restore this rabbit in Washington. [Copyright &y& Elsevier]