Overcoming radiotelemetry bias in habitat-selection studies

For many species, determination of habitat selection is based on habitat-us e data obtained through radiotelemetry. Recent papers pertaining to study t echniques have largely ignored the effect of habitat-dependent bias in the performance of radiotelemetry systems. Such biases cannot be overcome by in creasing radiotelemetry precision, excluding data, or increasing sample siz es, as the biases are centred around data that are missing or that contain habitat-dependent errors in location. The problem is best addressed at the data-analysis stage through the use of geographic information systems. We u sed Monte Carlo simulations to assess the effect of habitat-dependent bias in radiotelemetry studies on the assessment of habitat selection. We looked at the effects of habitat-patch size, level of telemetry signal inhibition , level of habitat co-occurrence, and selection pattern. We demonstrated th at regarding use as the composition of habitat types within a circular area around each telemetry location can help to overcome the inaccurate assessm ent of habitat-selection patterns that biased data produce. The size of the circular area best able to overcome the bias is related to habitat patch s ize and to the level of association between two or more habitat types. Furt hermore, we argue that the characteristics of habitat mosaics selected by a nimals can and should be studied in this way.