Point-Transect Surveys for Songbirds: Robust Methodologies

Point Transect Surveys for Songbirds: Robust Methodologies

Seabirds At-Sea Surveys: The Line-Transect Method Outperforms the Point-Transect Alternative

Methods: We tested whether modeling of detection probabilities, and density estimates with their coefficients of variation obtained from the point-transect method provided more robust and precise results than the more commonly used line-transect method. We subdivided our data by species groups (alcids, and aerialist species), and into two behavior categories (flying vs. swimming). We also compu...

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...

Simulated likelihood methods for complex double-platform line transect surveys.

The conventional line transect approach of estimating effective search width from the perpendicular distance distribution is inappropriate in certain types of surveys, e.g., when an unknown fraction of the animals on the track line is detected, the animals can be observed only at discrete points in time, there are errors in positional measurements, and covariate heterogeneity exists in detectab...