期刊
JOURNAL OF WILDLIFE MANAGEMENT
卷 73, 期 3, 页码 392-398出版社
WILEY-BLACKWELL
DOI: 10.2193/2007-411
关键词
breeding pair surveys; detection probability; double-observer survey; North Dakota; pair counts; prairie ducks; roadside surveys; sightability
资金
- Delta Waterfowl Foundation
- University of Minnesota Agricultural Experiment Station
Current methods for conducting ground-based surveys of breeding waterfowl pairs make the unlikely assumption that detection probabilities are constant and approach 100%. To test this assumption, we conducted independent double-observer pair surveys in North Dakota, USA, to evaluate sources of variation in detection probabilities for 8 common species of prairie-nesting ducks. An experienced observer had 0.911 detection probability averaged over all 8 species (range 0.866-0.944) versus 0.790 (range 0.537-0.890) for a novice observer. Detection probabilities also varied substantially among species, but patterns were not consistent between observers. Detection probabilities declined as number of ducks per wetland increased, presumably due to difficulty in identifying large numbers of flushing ducks. Other covariates affecting detection probabilities included size of social groups, precipitation, survey methodology (roadside vs. walk-up), cloud cover, time of day, and amount of wetland vegetation, but these covariates only affected detection probabilities by 2-5%. Our results demonstrated that the assumption of 100% detection probabilities for ground-based waterfowl counts was clearly false and surveys based on this erroneous assumption underestimated population size by 10-29%. We recommend that future investigators measure detection probabilities explicitly by using double-observer methodologies. (JOURNAL OF WILDLIFE MANAGEMENT 73(3): 392398; 2009)
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据