Seasonal resource selection and movement ecology of free‐ranging horses in the western United States

Abstract

Understanding factors driving resource selection and habitat use of different species is an important component of management and conservation. Feral horses (Equus caballus) are free ranging across various vegetation types in the western United States, yet few studies have quantified their resource selection and seasonal use. We conducted a study to determine effects of vegetation community, distance to water, and topographic variables on seasonal resource selection in 2 feral horse populations in Great Basin sagebrush (Artemisia spp.) ecosystems of west-central Utah, USA: Conger Herd Management Area (HMA) and Frisco HMA.We deployed global positioning system (GPS) radio-collars on 38 female horses and GPS-transmitters braided and glued into the tail hair of 14 males, collecting locations every 2 hours for 1-4 years between 2016 and 2020. We calculated home range size and core use area of social groups (harems) and bachelor males using autocorrelated kernel density estimators for each biologically defined season (breeding, fall, and winter) per study year. We examined seasonal home range size and overlap of harem groups and bachelor males and compared movement speed of bachelors and harems among seasons. We determined seasonal resource selection in a use-availability framework using resource selection functions. We hypothesized that horses would select for areas of

Effects of telemetry collars on two free-roaming feral equid species

“…Our behavior results indicated minimal effects on horse or burro maintenance behaviors; results for horses showed they stood slightly more than uncollared horses, and collared burros were found to forage and stand more at Lake Pleasant; no behavioral effects of wearing collars were seen on burros at Sinbad. Changes in movement have been reported in an African equid: collared plains zebras had lower movement rates than uncollared [ 44 ], but in our study it is likely that factors such as resource availability and time of year were stronger predictors of animal movement and behavior than wearing a collar [ 20 ]. Any minor differences in observed behavior were not found to be correlated with any negative demographic effect.…”

“…In 2013, the National Research Council advised more research was needed on several topics related to horse and burro management, including increased information on basic horse and burro ecology [19]. Since then, many studies have added to the body of knowledge on free-roaming equid ecology in North America [e.g., 10,[20][21][22][23], diet [24,25], behavior [26,27], and interactions with native wildlife [e.g., [28][29][30][31]]. Yet only a few studies have applied global positioning system (GPS) collar technology in studies of free-roaming equids in North America [10,20,32,33].…”

“…Since then, many studies have added to the body of knowledge on free-roaming equid ecology in North America [e.g., 10,[20][21][22][23], diet [24,25], behavior [26,27], and interactions with native wildlife [e.g., [28][29][30][31]]. Yet only a few studies have applied global positioning system (GPS) collar technology in studies of free-roaming equids in North America [10,20,32,33]. This is primarily because in a study conducted in the 1980s, collars caused some severe effects to individual horses, largely due to changes in neck sizes of stallions resulting from abnormally large weight gains from year 1 to year 2 of that study and the lack of a release mechanism on those collars [34].…”

Moose and white‐tailed deer mortality peaks in fall and late winter

“…Wildebeest ( Connochaetes taurinus ; Hopcraft et al 2014) and caribou ( Rangifer tarandus ; Couriot et al 2023) exhibit large‐scale space use changes via migration, whereas roe deer ( Capreolus capreolus ) exhibit this pattern at smaller spatial extents by shifting their functional home ranges (Couriot et al 2018). Resource selection by range‐resident populations of sika deer ( Cervus nippon ; Latham et al 2015) and feral horses ( Equus caballus ; Schoenecker et al 2023) also demonstrates seasonal changes in response to forage availability. Space use change is often risky (Avgar et al 2014, Forrester et al 2015) and, among partially migratory populations, migratory individuals generally incur greater mortality risk (Hebblewhite and Merrill 2007, Robinson et al 2010).…”

Multi-isotope reconstruction of Late Pleistocene large-herbivore biogeography and mobility patterns in Central Europe

“…Maximum home range size in modern wild bands can vary from between 12 and 48.2 km 2 in mesic steppe grasslands 42 and forests 43,44 , to <1357 km 2 in arid environments 45 , as movements are highly dependent on seasonal forage and water availability (Fig. 1b) (Supplementary Note 1) 42,[46][47][48] . Evidence for migratory behaviour in the European mammoth (Mammuthus primigenius) during the Pleistocene is lacking, although certain individuals may have undertaken long-distance seasonal migrations 49 , similar to some modern elephant populations (Supplementary Note 1) 50,51 .…”