Results 201 to 210 of about 16,314 (251)

Line Transect Methods for Plant Surveys

Biometrics, 2007
SummaryInterest in surveys for monitoring plant abundance is increasing, due in part to the need to quantify the rate of loss of biodiversity. Line transect sampling offers an efficient way to monitor many species. However, the method does not work well in some circumstances, for example on small survey plots, when the plant species has a strongly ...
Alison Johnston, Tiago A Marques, Peter Henrys   +2 more
exaly   +4 more sources

Incorporating Covariates into Standard Line Transect Analyses

Biometrics, 2003
Summary. An implicit assumption of standard line transect methodology is that detection probabilities depend solely on the perpendicular distance of detected objects to the transect line. Heterogeneity in detection probabilities is commonly minimized using stratification, but this may be precluded by small sample sizes. We develop a general methodology
Stephen Buckland
exaly   +4 more sources

Adaptive Line Transect Sampling

Biometrics, 2002
Adaptive line transect sampling offers the potential of improved population density estimation efficiency over conventional line transect sampling when populations are spatially clustered. In adaptive sampling, survey effort is increased when areas of high animal density are located, thereby increasing the number of observations.
J H, Pollard, D, Palka, S T, Buckland
exaly   +3 more sources

A Remark on the Line Transect Method

Biometrical Journal, 1982
AbstractThis paper gives a re‐formulation of a model for the line transect method in terms of the theory of stationary point processes. The well‐known formulae for this method are shown to be valid also under very general assumptions.
exaly   +3 more sources

On the Line Transect Sampling Method

Biometrics, 1974
Theory has been developed in the present paper for estimating wildlife density and its standard error by the line transect method of sampling using both right angle and radial distances and based on different assumptions than those made by Gates et al. [1968]. It is shown that relatively better fits are realized when the assumptions are tested with the
Sen, A. R., Tourigny, J., Smith, G. E. J.   +2 more
openaire   +1 more source

Comparison of Helicopter Line Transects with Walked Line Transects for Estimating Densities of Kangaroos

Wildlife Research, 1997
The performance of helicopter surveys for estimating population densities of red kangaroos ( Macropus rufus ), eastern grey kangaroos ( Macropus giganteus ) and common wallaroos ( Macropus robustus ) was investigated by comparing line-transect density estimates obtained from helicopter surveys with those from ground (walked) surveys.
Clancy, T. F., Pople, A. R., Gibson, L. A.   +2 more
openaire   +3 more sources

Sequential Estimation in Line Transect Surveys

Biometrics, 2002
This article considers using sequential procedures to determine the amount of survey effort required in a line transect survey in order to achieve a certain precision level in estimating the abundance of a biological population. Sequential procedures are constructed for both parametric and nonparametric animal abundance estimators.
Yip, PSF, Zhou, Y, Chen, SX
openaire   +5 more sources

Line transects

2001
Abstract The purpose of this chapter is to illustrate the application of the theory of Chapter 3 to line transect data, and to present the strategies for analysis outlined in Section 2.5. In general, the parameter f (0) in a line transect analysis does not have a closed form estimator. That is, for most models f(0) cannot be expressed as
S T Buckland, D R Anderson, K P Burnham, J L Laake, D L Borchers, L Thomas   +5 more
openaire   +1 more source

Size Bias in Line Transect Sampling

Biometrics, 1987
Line transect sampling is used to estimate the number of individuals in a study area. It is usually assumed that the detections of individuals constitute independent events, and that the probability of detecting an item is a function of its perpendicular distance from the transect.
Drummer, Thomas D., McDonald, Lyman L.
openaire   +2 more sources

Double‐Observer Line Transect Methods: Levels of Independence

Biometrics, 2010
SummaryDouble‐observer line transect methods are becoming increasingly widespread, especially for the estimation of marine mammal abundance from aerial and shipboard surveys when detection of animals on the line is uncertain. The resulting data supplement conventional distance sampling data with two‐sample mark–recapture data.
David Borchers, Stephen Buckland
exaly   +6 more sources