A Hierarchical Modeling Framework for Multiple Observer Transect Surveys

A Hierarchical Modeling Framework for Multiple Observer Transect Surveys

Ecologists often use multiple observer transect surveys to census animal populations. In addition to animal counts, these surveys produce sequences of detections and non-detections for each observer. When combined with additional data (i.e. covariates such as distance from the transect line), these sequences provide the additional information to estimate absolute abundance when detectability on...

Double-observer line transect surveys with Markov-modulated Poisson process models for animal availability.

We develop maximum likelihood methods 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 available. These incorporate a Markov-modulated Poisson process model for animal availability, allowing more clustered availability events than is possible with Poisson avail...

Line transect methods for plant surveys.

Interest 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 aggregated distribution, or when plants that are on th...

Parametric models for line transect surveys

With data from line transeot 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 parameter in the distributions of detection distances. Seve...

Point Transect Surveys for Songbirds: Robust Methodologies