Ground-based surveys for Dall’s sheep in Denali National Park: 2008-2017 report
Borg BL. 2018. Ground-based surveys for Dall’s sheep in Denali National Park: 2008-2017 report. Natural Resource Report. NPS/DENA/NRR—2018/1611. National Park Service. Fort Collins, Colorado
Ground-based Dall’s sheep surveys were conducted annually along the Denali National Park Road corridor from 2008 to 2017. Previous ground surveys occurred from 1974 to 1996 but these were discontinued from 1997 to 2007. From 2008 to 2017, areas surveyed varied slightly from year to year depending on weather conditions and information gathered from aerial overflights prior to the surveys. From 2008 to 2017, a total of 41 to 184 sheep were counted and classified each year. Estimates of sheep productivity (expressed as the number of lambs per 100 ewes or ewe-like sheep) ranged from 3.57 (2013) to 50 (2016) lambs per 100 ewes. The estimate of productivity in 2012 (10.94) and 2013 (3.57) were the lowest recorded since 1993. The productivity estimate from 2013 was the lowest recorded during ground surveys since 1974. This drop occurred following a winter with very late snowmelt and record cold spring temperatures, which potentially covered spring forage and impacted natality and/or early survival of lambs.
- Type
- Published Report
- Authors
- Borg, Bridget
- Date of Issue
- 2018-03
- Publisher
- National Park Service
- Units
- DENA , NRSS
- Keywords
- Alaska, Dall, DENA, Denali National Park, monitoring, Preserve, Sheep, wildlife
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Mammals