Open AccessMark‐resight superpopulation estimation of a wintering elk Cervus elaphus canadensis herd
Author(s) -
Gould William R.,
Smallidge Samuel T.,
Thompson Bruce C.
Publication year - 2005
Publication title -
wildlife biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.566
H-Index - 52
eISSN - 1903-220X
pISSN - 0909-6396
DOI - 10.2981/0909-6396(2005)11[341:mseoaw]2.0.co;2
Subject(s) - geography , quadrat , statistics , population , abundance (ecology) , estimation , estimator , herd , abundance estimation , survey methodology , population size , mathematics , ecology , biology , demography , transect , management , sociology , economics
We executed four mark‐resight helicopter surveys during the winter months January–February for each of the three years 1999–2001 at 7–10 day intervals to estimate population size of a wintering elk Cervus elaphus canadensis herd in northern New Mexico. We counted numbers of radio‐collared and uncollared elk on a simple random sample of quadrats from the study area. Because we were unable to survey the entire study area, we adopted a superpopulation approach to estimating population size, in which the total number of collared animals within and proximate to the entire study area was determined from an independent fixed‐wing aircraft. The total number of collared animals available on the quadrats surveyed was also determined and facilitated detectability estimation. We executed superpopulation estimation via the joint hypergeometric estimator using the ratio of marked elk counted to the known number extant as an estimate of effective detectability. Superpopulation size estimates were approximately four times larger than previously suspected in the vicinity of the study area. Despite consistent survey methodology, actual detection rates varied within winter periods, indicating that multiple resight flights are important for improved estimator performance. Variable detectability also suggests that reliance on mere counts of observed individuals in our area may not accurately reflect abundance.