Assessing Catharus bicknelli (Bicknell’s Thrush) habitat dynamics: A high-resolution model based on LiDAR metrics

Abstract

Assessing species occurrences can be challenging due to issues such as species detectability and difficulties in accessing habitats for surveys. These limitations hinder the ability to adequately inform conservation or management decisions, particularly for cryptic species, which can be partially addressed with high-resolution, spatial explicit models. However, high-resolution, spatially explicit models projecting species can help resolve these challenges. We modeled the probability of occurrence of Catharus bicknelli (Bicknell’s Thrush), globally vulnerable species, in southern Québec (Canada) using LiDAR-derived metrics. The model was calibrated with 139 occurrences (with 10-m spatial accuracy), each paired with 10 random locations within a 523–1,569 m buffer, and validated with an independent dataset of 3,928 point counts. Based on model output, we applied 2 statistical thresholds to guide decision-making. The probability of occurrence of the species was highest in dense, low-canopy balsam fir stands at high elevation. The top-ranked model also included forest succession, with an adjustment to canopy height to account for tree growth since the LiDAR data were acquired. This modeling approach provides a valuable tool for tracking the spatio-temporal dynamics of C. bicknelli habitat and informing more effective conservation strategies for this species at risk in Canada.