Habitat specialists as conservation umbrellas: Do areas managed for greater sage‐grouse also protect pygmy rabbits?

Abstract

AbstractSagebrush 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.