Geographic Distribution and Neuropathology of Elaeophora schneideri in Moose (Alces alces shirasi) in Idaho, USA.

Elaeophorosis, infection by the filarial worm Elaeophora schneideri, is a parasitic disease of wild ungulates in North America; however, our understanding of the relevance of E. schneideri to moose (Alces alces) morbidity and mortality is incomplete. Between March 2020 and July 2022, necropsy and histopathology were performed on 61 Shiras moose (Alces alces shirasi) in Idaho, US. Among the 41 adults (greater than 1 yr old), 21 moose were from northern Idaho, and 20 were from southeastern Idaho. Elaeophorosis was diagnosed in 24% (10 of 41). All 10 infected moose were from southeastern Idaho; none of the 21 moose from northern Idaho were infected. No juvenile moose (nine from northern and 11 from southeastern Idaho) were infected. Microfilariae were detected histologically in 9 of 10 infected moose, most consistently in brain tissue associated with lesions indicative of ischemic injury to the neuroparenchyma attributed to occlusion of arterioles and capillaries by microfilariae or fibrin thrombi, including edema, necrosis, and glial nodules. Microfilariae found in other tissues of the head, including the eye, tongue, and pinnae of some animals, as well as in lung, heart, liver, and kidney, typically were associated with inflammation. Three of the 10 infected moose had cropped ears attributed to elaeophorosis, and four exhibited abnormal behavior, which may have been due to neuropathology associated with E. schneideri microfilariae in the brain.

Seasonal shifts in pronghorn antelope (Antilocapra americana) diets under a new lens: Examining diet composition using a molecular technique.

Foraging is one of the most fundamental activities contributing to the maximization of an animal's fitness, and thus herbivores must optimize their diet selection and intake to meet their nutrient demands for survival, growth, and reproduction. Using plant DNA barcoding, we determined diet composition of five subpopulations of adult female pronghorn antelope (Antilocapra americana) grazing rangelands in southern and southeastern Idaho, USA. Fecal samples were collected for two years (2018-2019), and across metabolically-important adult female life history stages (late gestation, early lactation, breeding season). Plant DNA barcoding yielded 137 detected species within pronghorn diets across subpopulations and sampling periods with forbs being the most abundant. Pronghorn dietary functional group composition ranged from 52.2-60.3% from forbs followed by shrubs (22.6-28.2%), graminoids (8.7-15.7%), and legumes (5.5-9.6%). Dietary protein intake was also highest from forbs and ranged from 32.4-62.4% followed by graminoids (1.2-43.1%), shrubs (18.7-21.3%), and legumes (2.6-7.4%). We found significant intra- and interannual differences in the mean number of genera-based plant detections in pronghorn diets. Dietary protein intake of cultivated legumes (e.g., alfalfa [Medicago sativa] and sainfoin [Onobrychis viciifolia]) was lower than expected, ranging from <1.0-30.8%, suggesting that even within an agricultural-dominated landscape, factors other than plant nutritional composition contributed to pronghorn diets. Although the plant DNA barcoding technique exhibits limitations, it demonstrated potential for elucidating pronghorn dietary species richness, particularly for plants consumed in small proportions, as well as for observing temporal fluctuations in functional group composition and dietary protein intake explained through the interplay between environmental factors, plant chemical composition, and the animals' physiological needs.

Effects of large-scale disturbance on animal space use: Functional responses by greater sage-grouse after megafire.

Global change has altered the nature of disturbance regimes, and megafire events are increasingly common. Megafires result in immediate changes to habitat available to terrestrial wildlife over broad landscapes, yet we know surprisingly little about how such changes shape space use of sensitive species in habitat that remains. Functional responses provide a framework for understanding and predicting changes in space use following habitat alteration, but no previous studies have assessed functional responses as a consequence of megafire. We studied space use and tested for functional responses in habitat use by breeding greater sage-grouse (Centrocercus urophasianus) before and after landscape-level changes induced by a >40,000 ha, high-intensity megafire that burned sagebrush steppe in eastern Idaho, USA. We also incorporated functional responses into predictive resource selection functions (RSFs) to map breeding habitat before and after the fire. Megafire had strong effects on the distribution of available resources and resulted in context-dependent habitat use that was heterogeneous across different components of habitat. We observed functional responses in the use and selection of a variety of resources (shrubs and herbaceous vegetation) for both nesting and brood rearing. Functional responses in the use of nesting habitat were influenced by the overarching effect of megafire on vegetation, whereas responses during brood rearing appeared to be driven by individual variation in available resources that were conditional on nest locations. Importantly, RSFs built using data collected prior to the burn also had poor transferability for predicting space use in a post-megafire landscape. These results have strong implications for understanding and predicting how animals respond to a rapidly changing environment, given that increased severity, frequency, and extent of wildfire are consequences of global change with the capacity to reshape ecosystems. We therefore demonstrate a conceptual framework to better understand space use and aid habitat conservation for wildlife in a rapidly changing world.