You are here:
ESTIMATING PROPORTION OF AREA OCCUPIED UNDER COMPLEX SURVEY DESIGNS
Olsen, A R. ESTIMATING PROPORTION OF AREA OCCUPIED UNDER COMPLEX SURVEY DESIGNS. Presented at Department of Statistics, Colorado State Univ, Ft. Collins, CO, April 23, 2004.
Estimating proportion of sites occupied, or proportion of area occupied (PAO) is a common problem in environmental studies. Typically, field surveys do not ensure that occupancy of a site is made with perfect detection. Maximum likelihood estimation of site occupancy rates when detection probabilities are less than one have been developed by MacKenzie et al. (2002) under the assumption of a simple random sample. Their procedures are generalized to cover complex survey designs, in particular, survey designs with stratification, cluster sampling, and unequal probability sampling. Three studies are used to motivate the problem and illustrate the estimation problem. One study is of fish species present/absence in northeastern lakes based on an unequal probability survey design conducted by EMAP in 1992-1996. The other two are from two studies conducted by the US Geological Survey's Amphibian Monitoring and Research Initiative on the occurrence of specific amphibian species in ponds in Olympic National Park and southeastern Oregon. In both studies a two-stage cluster sample was used where the first stage primary sampling units are 5th field hydrologic units and the second stage are individual ponds located within each selected hydrologic unit. The presentation will describe the survey designs, present PAO estimation for complex survey designs, and illustrate the estimation with data from the studies.
Record Details:Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB
WESTERN ECOLOGY DIVISION
AQUATIC MONITORING & BIOASSESSMENT BRANCH