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Estimating the encounter rate variance in distance sampling

Biometrics

By:
, , , , , ,
DOI: 10.1111/j.1541-0420.2008.01018.x

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Abstract

The dominant source of variance in line transect sampling is usually the encounter rate variance. Systematic survey designs are often used to reduce the true variability among different realizations of the design, but estimating the variance is difficult and estimators typically approximate the variance by treating the design as a simple random sample of lines. We explore the properties of different encounter rate variance estimators under random and systematic designs. We show that a design-based variance estimator improves upon the model-based estimator of Buckland et al. (2001, Introduction to Distance Sampling. Oxford: Oxford University Press, p. 79) when transects are positioned at random. However, if populations exhibit strong spatial trends, both estimators can have substantial positive bias under systematic designs. We show that poststratification is effective in reducing this bias. ?? 2008, The International Biometric Society.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Estimating the encounter rate variance in distance sampling
Series title:
Biometrics
DOI:
10.1111/j.1541-0420.2008.01018.x
Volume
65
Issue:
1
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Biometrics
First page:
225
Last page:
236
Number of Pages:
12