Results 251 to 260 of about 117,053 (296)

Line Transect Estimators for Left-Truncated Distributions

Biometrics, 1985
Left-truncated line transect data sets may occur when surveying with certain types of aircraft where the observer cannot look straight down. A general model of left-truncation in line transect sampling is developed and parametric estimators are derived in such cases when the underlying distribution of right-angle distances is either exponentially or ...
Alldredge, J. Richard, Gates, Charles E.
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A Robust Line Transect Method

Biometrics, 1992
SUMMARY Standard line transect estimation is not robust to departures from the assumptions that animals do not move in response to the observer before detection and that all animals on or near the trackline are detected. We propose field methodology and analysis methods for which estimates are robust to the first assumption and do not require the ...
Stephen T. Buckland, Benjamin J. Turnock
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Line Transect Sampling from a Curving Path

Biometrics, 2001
Cutting straight line transects through dense forest is time consuming and expensive when large areas need to be surveyed for rare or highly clustered species. We argue that existing paths or game trails may be suitable as transects for line transect sampling even though they will not, in general, run straight.
L, Hiby, M B, Krishna
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Mark-Recapture Models for Line Transect Surveys

Biometrics, 1998
Summary: One of the key assumptions of conventional line transect (LT) theory is that all animals in the observer's path are detected. When this assumption fails, simultaneous survey by two independent observers can be used to estimate detection probabilities and abundance.
Borchers, David L., Zucchini, Walter, Fewster, Rachel M.   +2 more
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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
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Measurement Errors in Line Transect Surveys

Biometrics, 1998
Summary: An important assumption used in the analysis of line transect data for animal abundance estimation is that the perpendicular sighting distances of detected animals to transect lines are measured accurately. However, in many line transect surveys, the sighting distances are likely to be subject to measurement errors.
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Parametric Models for Line Transect Surveys

Biometrika, 1979
SUMMARY With data from line transect surveys, the pattern of distances at which animals are detected provides the information for estimating the area which the observer effectively surveys. This paper suggests a parametric structure for the problem wherein this area is characterized by an effective half-width parameter which appears as a scale ...
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Some Mathematical Models for Line Transect Sampling

Biometrical Journal, 1985
AbstractANDERSON and POSPAHALA (1970) investigated the estimation of wildlife population size using the belt or line transect sampling method and devised a correction for bias, thus leading to an estimator with interesting characteristics. This work was given a uniform mathematical framework in BURNHAM and ANDERSON (1976).
Anderson, D. R., Burnham, K. P., Crain, B. R.   +2 more
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Spatial Methods for Line Transect Surveys

Biometrics, 1998
Summary: Line transect surveys have traditionally been used only to estimate the mean intensity of an underlying spatial point process. We propose a test for complete spatial randomness and a method of estimating the clustering parameters in a simplified Neyman-Scott Poisson model, using observations collected in a line transect survey with a Gaussian ...
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Spatial models for line transect sampling

Journal of Agricultural, Biological, and Environmental Statistics, 2004
This article develops methods for fitting spatial models to line transect data. These allow animal density to be related to topographical, environmental, habitat, and other spatial variables, helping wildlife managers to identify the factors that affect abundance.
Sharon L. Hedley, Stephen T. Buckland
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