Mountain goat survival in coastal Alaska: Effects of age,sex, and climate |
| |
| Authors: | Kevin S. White Grey W. Pendleton David Crowley Herman J. Griese Kris J. Hundertmark Thomas Mcdonough Lyman Nichols Matt Robus Christian A. Smith John W. Schoen |
| |
| Affiliation: | 1. Alaska Department of Fish and Game, Division of Wildlife Conservation, PO Box 110024, 802 Third Street, Douglas, AK 99824, USA;2. Alaska Department of Fish and Game, Division of Wildlife Conservation, PO Box 669, Cordova, AK, USA;3. 673 CES/CEANC, 6326 Arctic Warrior Drive, Joint Base Elmendorf-Richardson, AK, USA;4. University of Alaska, Institute of Arctic Biology, Fairbanks, AK, USA;5. Alaska Department of Fish and Game, Division of Wildlife Conservation, 3298 Douglas Place, Homer, AK, USA;6. Alaska Department of Fish and Game, Division of Wildlife Conservation, Cooper Landing, AK, USA Deceased.;7. Alaska Department of Fish and Game, Division of Wildlife Conservation, PO Box 115526, Juneau, AK, USA;8. Wildlife Management Institute, 5450 Tumbleweed Dr. Helena, MT, USA;9. Audubon Alaska, 715 L Street, Suite 200, Anchorage, AK, USA |
| |
| Abstract: | Ecological theory predicts that individual survival should vary between sex and age categories due to differences in allocation of nutritional resources for growth and reproductive activities. During periods of environmental stress, such relationships may be exacerbated, and affect sex and age classes differently. We evaluated support for hypotheses about the relative roles of sex, age, and winter and summer climate on the probability of mountain goat (Oreamnos americanus) survival in coastal Alaska. Specifically, we used known-fates analyses (Program MARK) to model the effects of age, sex, and climatic variation on survival using data collected from 279 radio-marked mountain goats (118 M, 161 F) in 9 separate study areas during 1977–2008. Models including age, sex, winter snowfall, and average daily summer temperature (during Jul–Aug) best explained variation in survival probability of mountain goats. Specifically, our findings revealed that old animals (9+ yr) have lower survival than younger animals. In addition, males tended to have lower survival than females, though differences only existed among prime-aged adult (5–8 yr) and old (9+ yr) age classes. Winter climate exerted the strongest effects on mountain goat survival; summer climate, however, was significant and principally influenced survival during the following winter via indirect effects. Furthermore, old animals were more sensitive to the effects of winter conditions than young or prime-aged animals. These findings detail how climate interacts with sex and age characteristics to affect mountain goat survival. Critically, we provide baseline survival rate statistics across various age, sex, and climate scenarios. These data will assist conservation and management of mountain goats by enabling detailed, model-based demographic forecasting of human and/or climate-based population impacts. © 2011 The Wildlife Society. |
| |
| Keywords: | Alaska climate growing degree days mountain goat Oreamnos americanus snow summer survival winter |
|
|
