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Mule (Odocoileus hemionus) and white‐tailed deer (Odocoileus virginianus) are congeneric and share similar life histories, yet their distribution is segregated across much of North America. Extensive research on both species within and outside their zone of co‐occurrence has not fully explained these distribution patterns, especially the potential role of diet and foraging behavior. Therefore, we used a common garden experiment to compare diet composition, diet quality, foraging behavior, and intake of tractable mule and white‐tailed deer foraging together within the dry Douglas‐fir (Pseudotsuga menziesii)/ponderosa pine (Pinus ponderosa) forests of northeastern Washington. We sampled at 21 0.5‐ha sites from June to August 2016. We used standard bite count techniques coupled with forage biomass sampling, behavioral observations, and nutritional analyses to compare the foraging ecology of the two species. Mule and white‐tailed deer had similar activity patterns. However, mule deer took larger bites and harvested food faster than white‐tailed deer, and white‐tailed deer consumed more diverse but higher‐quality diets than mule deer. These differences resulted in mule deer acquiring ~25% more dry matter and digestible energy per day. About 90% of the diets consumed by both deer species consisted of deciduous shrubs and forbs, and they selected many of the same plant species. However, overall diet composition was 38% dissimilar, with mule deer consuming diets that were more likely to contain shrubs with higher levels of tannins and lower levels of dry matter digestibility than diets eaten by white‐tailed deer. Dietary overlap was greatest at both very low and very high forage biomass, indicating potential for modest resource competition or partitioning. Our research provides evidence that differences in diet composition of mule and white‐tailed deer do not merely reflect differences in habitat selection, but also suggest the species differ in their fundamental nutritional niches.

Fire suppression has increased the canopy cover, stocking density, and fuel loads of dry forests in the inland northwestern United States. These changes not only lead to high-severity, stand-replacing wildfires that may threaten human safety and further alter natural forest communities, but also reduce light transmission to the forest floor, which can limit production of herbaceous and woody understory vegetation that serves as forage for wild ungulates. Therefore, forest managers have implemented fuels reduction treatments that reduce the density of standing trees in mature stands to restore historic conditions, promote healthy forests, and reduce wildfire risk. To test the hypothesis that these treatments also improve the quality and quantity of forage resources for wild ungulates, we measured biomass, plant species composition, and nutritional quality of understory vegetation in 106 untreated and treated 0.5-ha plots that ranged from 1 to 22 years since treatment and 2–100% canopy cover in Douglas-fir (Pseudotsuga menziesii)/ponderosa pine (Pinus ponderosa) forests in the Colville National Forest of northeastern Washington. On average, fuels reduction treatments halved basal area and overstory canopy cover, doubling understory vegetation biomass. The most nutritious plants (i.e., composing suitable biomass) and plants most likely to be consumed by deer (i.e., acceptable biomass) increased with decreasing forest canopy cover, and increased with time since treatment for approximately 14 years post-harvest, but suitable biomass began declining thereafter. Understory plant biomass also responded to a range of site, weather, and environmental variables, especially those influencing moisture gradients. Our results indicate that active management prescriptions intended to reduce fuel loads posed by overstocked conifers can also increase the amount of high quality forage for deer and other wild ungulates, especially when carefully planning the timing, intensity, and rotation schedules of fuels reduction treatments.

The formerly widespread but now Vulnerable dorcas gazelle Gazella dorcas has declined markedly during the last 2 decades. The semi-captive population in M'Sabih Talaa Reserve, west-central Morocco, is genetically distinct and may be the last remnant of the Moroccan dorcas gazelle G. dorcas massaesyla. The last estimate of the size of this population was c. 200, in 1996. To assess the current population we used line-transect distance sampling to survey this population over five seasons from April 2008 to August 2009. The estimated population declined from 113 to 87 individuals from April to November 2008, increased to 111 in February 2009 (primarily because of recruitment), declined to 99 from February to April 2009, and to 95 by August 2009. These results indicate a decline of nearly 50% in < 15 years. The main conservation actions required for this subspecies are the suppression of poaching and feral dogs, the creation of other reserves to receive dorcas gazelles from M'Sabih Talaa (to avoid loss of the single population from a catastrophic event), and the implementation of a genetic management programme.