Line transect surveys
Design and analysis of line transect surveys for primates
... of Line Transect Surveys for Primates Stephen ...Abstract Line transect surveys are widely used for estimating abundance of primate ...primate surveys often do not follow ...
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Small-boat surveys for coastal dolphins: line-transect surveys of Hector’s dolphins (Cephalorhynchus hectori)
... that line-transect surveys are often conducted from large (>50 m) vessels ...ity surveys such as those conducted for harbor porpoise in the ...
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Using hidden Markov models to deal with availability bias on line transect surveys
... for line transect surveys of animals that are stochastically unavailable for detection while within detection ...when surveys are not close to being instantaneous, as can estimators that ...
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Accommodating availability bias on line transect surveys using hidden Markov models
... model, line transect survey ...on line transect surveys. Line transect methods are well developed for situations in which animals are detected with certainty at zero ...
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Global analysis of cetacean line transect surveys : detecting trends in cetacean density
... repeated surveys are lacking, and alterna- tive approaches to trend detection must be ...of line- transect survey records to determine whether temporal trends could be detected when survey effort ...
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Double observer line transect surveys with Markov modulated Poisson process models for animal availability
... for line transect surveys in which animals go undetected at distance zero, either because they are stochastically unavailable while within view or because they are missed when they are avail- ...the ...
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Global coverage of cetacean line transect surveys : status quo, data gaps and future challenges
... visual line-transect surveys and encoded ...430 surveys conducted worldwide from ...of surveys conducted nor the survey effort had increased in recent ...from ...
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Methods for investigating measurement error in cetacean line transect surveys
... This study serves as an example of the value of so-called ships of opportunity not only for collecting cetacean sightings data, but also as inexpensive platforms for conducting experiments that inform researchers about ...
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Methods for estimating sperm whale abundance from passive acoustic line transect surveys
... We take the linking of clicks from a survey (or transect) into click segments “known” to come from the same whale, as given. It may be that more than one segment comes from the same whale, but this we do not know. ...
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Bayesian state-space model of fin whale abundance trends from a 1991–2008 time series of line-transect surveys in the California Current
... 2. We demonstrate a Bayesian approach for estimating abundance and population trends, using a time series of line-transect data for endangered fin whales Balaenoptera physalus off the west coast of the United ...
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Humpback whale Megaptera novaeangliae (Cetartiodactyla: Balaenopteridae) group sizes in line transect ship surveys : an evaluation of observer errors
... Therefore, it is expected that estimates of group size will vary according to the observation platform and conditions. To obtain the most robust estimates, it is important to develop an understanding of such variation, ...
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Designing a shipboard line transect survey to estimate cetacean abundance off the Azores Archipelago, Portugal
... design. Line transect surveys are commonly applied to wildlife population assessments in which the primary purpose of a survey design is to ensure that the critical distance sampling assumptions are ...
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Line Transect Methods for Plant Surveys
... in line transect sampling, the lines would be resampled (Buckland et ...for surveys of plants, bootstrap resampling of lines yields poor estimates of ...
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POINT TRANSECT SURVEYS FOR SONGBIRDS: ROBUST METHODOLOGIES
... sings, its song almost certainly will be heard. Further, movement of birds that is independent of the observer does not bias the method; we record the location of the songburst, which is well-defined, rather than the ...
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Double-observer line transect methods : levels of independence
... methods, line transect methods use knowledge of the distribution of a covariate which affects detection probability (namely distance from the transect line) in ...double-observer line ...
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Assessing the effects of measurement errors in line transect sampling
... A simulation study was carried out in which known amount of measurement error can be added to error-free line transect data (i.e. true perpendicular distances) to determine the effects o[r] ...
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Double observer line transect methods : levels of independence
... Double-observer line transect survey methods were used because for many species detection of animals on the trackline was expected to be less than ...
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The effect of animal movement on line transect estimates of abundance
... strip transect case, was used, where all animals moved in straight lines at the same speed but each in a randomly assigned ...the line compared with linear move- ment, and so bias will be less as bias ...
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Kernel Estimation in Line Transect Sampling for Parametric Model
... Line transect sampling is a common method used in ecology for sampling the sample required. It is an important procedure for estimating the population density of objects in interested study area. There are ...
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Size bias in line transect sampling: A field test
... In Figure 1 the estimated probability of sighting is plotted against perpendicular distance for transect 1 for each group size separatelY'.. 2.2 The Bxponential Power Sighting Function.[r] ...
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