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**1 - 6**of**6**### REVIEW Distance software: design and analysis of distance sampling surveys for estimating population size

"... 1. Distance sampling is a widely used technique for estimating the size or density of biological populations.Many distance sampling designs andmost analyses use the softwareDistance. 2. We briefly review distance sampling and its assumptions, outline the history, structure and capabilities of Distan ..."

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1. Distance sampling is a widely used technique for estimating the size or density of biological populations.Many distance sampling designs andmost analyses use the softwareDistance. 2. We briefly review distance sampling and its assumptions, outline the history, structure and capabilities of Distance, and provide hints on its use. 3. Good survey design is a crucial prerequisite for obtaining reliable results. Distance has a survey design engine, with a built-in geographic information system, that allows properties of different pro-posed designs to be examined via simulation, and survey plans to be generated. 4. A first step in analysis of distance sampling data is modelling the probability of detection. Distance contains three increasingly sophisticated analysis engines for this: conventional distance sampling, which models detection probability as a function of distance from the transect and assumes all objects at zero distance are detected; multiple-covariate distance sampling, which allows covariates in addition to distance; and mark–recapture distance sampling, which relaxes the assumption of certain detection at zero distance. 5. All three engines allow estimation of density or abundance, stratified if required, with associated measures of precision calculated either analytically or via the bootstrap.

### Distance sampling

"... Distance sampling is a widely used group of closely related methods for estimating the density and/or abundance of biological populations. The main methods are line-transect sampling and point-transect sampling (also called variable circular plot sam-pling). These have been used successfully in a ve ..."

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Distance sampling is a widely used group of closely related methods for estimating the density and/or abundance of biological populations. The main methods are line-transect sampling and point-transect sampling (also called variable circular plot sam-pling). These have been used successfully in a very diverse array of taxa, including trees, shrubs and herbs, insects, amphibians, reptiles, birds, fish, and marine and land mammals. In both cases, the basic idea is the same. One or more observers perform a standardized survey along a randomly located set of lines or points, searching for objects of interest (usually animals or clusters of animals). For each object detected, they record the distance from the line or point to the object. Not all the objects will be detected, but a fundamental assumption of the basic methods is that all objects that are actually on the line or point are detected. Intuitively, one would expect that objects become harder to detect with increasing distance from the line or point, resulting in fewer detections with increasing distance. The key to dis-tance sampling analyses is to fit a detection function to the observed distances, and use this fitted function to estimate the proportion of objects missed during the survey. From here, we can readily obtain point and interval estimates for the density and abundance of objects in the survey area. The basic methods (sometimes called standard or conventional distance sampling) are described in detail in Ref. 1, which is an updated version of Ref. 2. Various extensions and more advanced methods are considered in Ref. 3. Free software, Distance [4], provides for the design and analysis of distance sampling surveys, imple-menting the methods described in Ref. 1 and many of those in Ref. 3. Distance sampling is an extension of quadrat-based sampling methods. Two forms of quadrat sam-pling are strip transects, in which one or more observers move along a line, counting all objects within a predetermined distance of the line, and point

### Journal of Applied Ecology doi: 10.1111/j.1365-2664.2009.01737.x REVIEW Distance software: design and analysis of distance sampling surveys for estimating population size

"... 1. Distance sampling is a widely used technique for estimating the size or density of biological populations. Many distance sampling designs and most analyses use the software Distance. 2. We briefly review distance sampling and its assumptions, outline the history, structure and capabilities of Dis ..."

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1. Distance sampling is a widely used technique for estimating the size or density of biological populations. Many distance sampling designs and most analyses use the software Distance. 2. We briefly review distance sampling and its assumptions, outline the history, structure and capabilities of Distance, and provide hints on its use. 3. Good survey design is a crucial prerequisite for obtaining reliable results. Distance has a survey design engine, with a built-in geographic information system, that allows properties of different proposed designs to be examined via simulation, and survey plans to be generated. 4. A first step in analysis of distance sampling data is modelling the probability of detection. Distance contains three increasingly sophisticated analysis engines for this: conventional distance sampling, which models detection probability as a function of distance from the transect and assumes all objects at zero distance are detected; multiple-covariate distance sampling, which allows covariates in addition to distance; and mark–recapture distance sampling, which relaxes the assumption of certain detection at zero distance. 5. All three engines allow estimation of density or abundance, stratified if required, with associated measures of precision calculated either analytically or via the bootstrap.

### sampling surveys for estimating population size

"... Distance software: design and analysis of distance ..."

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### Supplementary materials for this article are available at 10.1007/s13253-014-0167-0. Bayesian Methods for Hierarchical Distance Sampling Models

"... The few distance sampling studies that use Bayesian methods typically consider only line transect sampling with a half-normal detection function. We present a Bayesian approach to analyse distance sampling data applicable to line and point tran-sects, exact and interval distance data and any detecti ..."

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The few distance sampling studies that use Bayesian methods typically consider only line transect sampling with a half-normal detection function. We present a Bayesian approach to analyse distance sampling data applicable to line and point tran-sects, exact and interval distance data and any detection function possibly including covariates affecting detection probabilities. We use an integrated likelihood which com-bines the detection and density models. For the latter, densities are related to covariates in a log-linear mixed effect Poisson model which accommodates correlated counts. We use a Metropolis-Hastings algorithm for updating parameters and a reversible jump al-gorithm to include model selection for both the detection function and density models. The approach is applied to a large-scale experimental design study of northern bob-white coveys where the interest was to assess the effect of establishing herbaceous buffers around agricultural fields in several states in the US on bird densities. Results were compared with those from an existing maximum likelihood approach that analyses the detection and density models in two stages. Both methods revealed an increase of covey densities on buffered fields. Our approach gave estimates with higher precision even though it does not condition on a known detection function for the density model.

### REVIEW

, 2010

"... Distance software: design and analysis of distance sampling surveys for estimating population size ..."

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Distance software: design and analysis of distance sampling surveys for estimating population size