Guided transect sampling for assessing sparse populations

Guided Transect Sampling is suggested for transect based surveys when sampl ing sparse and geographically scattered populations. It is a two-stage desi gn in which wide strips are selected in the first stage followed by a subsa mpling procedure guided by prior information in the second stage. As a basi s for the second stage, the target area is divided into grid-cells containi ng covariate data obtained, for example, by remote sensing. The general pri nciple can be coupled with different transect based survey methods such as strip sampling or line transect sampling. Also, different strategies for th e second stage guidance can be used, resulting in estimators with different properties. In this study, Guided Transect Sampling was compared with a tr aditional strip survey under different simulated forest conditions. The com parisons indicated that the proposed method can improve the efficiency of t ransect based inventories of sparse populations.