Prevalence and Mortality of Moose (Alces alces) Infected with Elaeophora schneideri in Montana, USA.

Elaeophora schneideri is a filarial nematode of North America that occasionally infects aberrant ruminant hosts such as moose (Alces alces). The role E. schneideri plays in clinical morbidity or mortality of moose remains uncertain. We sampled predominantly hunter-killed adult moose (n=127) to characterize the spatial patterns of prevalence and intensity of worms in carotid arteries of moose in Montana. We compared prevalence and intensity of E. schneideri within these moose to a separate sample of adult moose that died of health-related causes (n=34). We found lower prevalence in northwest Montana (0.06) than in the remainder of the state (0.42). We also found both higher prevalence of E. schneideri and higher intensity to be correlated with increased probability of health-related mortality. Our results suggest presence and intensity of E. schneideri correlate with mortality of moose, although the mechanisms of mortality remain uncertain.

Habitat selection by wolves and mountain lions during summer in western Montana.

In the Northern Rockies of the United States, predators like wolves (Canis lupus) and mountain lions (Puma concolor) have been implicated in fluctuations or declines in populations of game species like elk (Cervus canadensis) and mule deer (Odocoileus hemionus). In particular, local distributions of these predators may affect ungulate behavior, use of space, and dynamics. Our goal was to develop generalizable predictions of habitat selection by wolves and mountain lions across western Montana. We hypothesized both predator species would select habitat that maximized their chances of encountering and killing ungulates and that minimized their chances of encountering humans. We assessed habitat selection by these predators during summer using within-home range (3rd order) resource selection functions (RSFs) in multiple study areas throughout western Montana, and tested how generalizable RSF predictions were by applying them to out-of-sample telemetry data from separate study areas. Selection for vegetation cover-types varied substantially among wolves in different study areas. Nonetheless, our predictions of 3rd order selection by wolves were highly generalizable across different study areas. Wolves consistently selected simple topography where ungulate prey may be more susceptible to their cursorial hunting mode. Topographic features may serve as better proxies of predation risk by wolves than vegetation cover-types. Predictions of mountain lion distribution were less generalizable. Use of rugged terrain by mountain lions varied across ecosystem-types, likely because mountain lions targeted the habitats of different prey species in each study area. Our findings suggest that features that facilitate the hunting mode of a predator (i.e. simple topography for cursorial predators and hiding cover for stalking predators) may be more generalizable predictors of their habitat selection than features associated with local prey densities.