Influence of Environmental Variables on Survival Rates of Pronghorn (Antilocapra americana) Neonates Across Idaho
Date of Award:
Master of Science (MS)
Eric M. Gese
Eric M. Gese
Mary M. Conner
This study was completed to better understand pronghorn antelope (Antilocapra americana) populations found throughout Idaho. Antelope were studied in three separate and distinct study areas. The Big Desert, Camas Prairie, and Little Lost and Pahsimeroi valleys were all selected as study sites. Idaho Department of Fish and Game (IDFG) is concerned with current pronghorn populations found throughout Idaho. Pronghorn are a valued big game species found in Idaho. Increasing pronghorn populations in Idaho is a focus of IDFG.
We captured and VHF-collared pronghorn fawns found in our three study areas. Fawns were monitored daily with telemetry equipment for survival. Field necropsies were performed to determine cause of death for each fawn. We found that fawns across Idaho had acceptable survival rates compared to previous studies conducted on pronghorn. The highest cause of mortality on fawns was coyotes (Canis latrans). Other predators on pronghorn fawns were bobcats (Lynx rufus), golden eagles (Aquila chrysaetos), and black bear (Ursus americanus). We found that fawns radio-collared with a higher BMI (body mass index) were more likely to survive.
We examined other relationships that could have an effect on fawn survival. Rabbits (Lepus californicus, Lepus townsendii Sylvilagus nuttallii, Brachylagus idahoensis, Lepus americanu) and ground squirrels (Urocitellus armatus, Urocitellus mollis, Urocitellus elegans, Urocitellus columbianus) were examined to see if there population numbers had an effect on pronghorn fawn survival. We found a relationship between rabbit density and fawn survival, as rabbit density increased pronghorn fawn survival increased. Ground squirrel density was found to have no effect. Coyote density was studied to see if coyote density effected pronghorn survival. No relationship was found between coyote density and pronghorn fawn survival.
Habitat quality can impact animal populations. We examined habitat variables that could affect pronghorn fawn survival. NDVI (normalized difference vegetation index) was examined and we found no correlation in this study. Pronghorn fecal samples were collected and analyzed at a laboratory to look for diet quality correlation to pronghorn survival. We found a correlation between diet quality (DAPA) and pronghorn fawn survival. Diet quality can be linked to habitat quality, as habitat quality increases so does pronghorn fawn survival. Habitat quality, rabbits, and a fawn’s BMI all were linked to increased fawn survival. We recommend wildlife managers create and increase pronghorn habitat when possible to produce better pronghorn fawn survival.
Panting, Brett R., "Influence of Environmental Variables on Survival Rates of Pronghorn (Antilocapra americana) Neonates Across Idaho" (2018). All Graduate Theses and Dissertations. 7410.
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