Abstract 995 – Assessing Changes in Distribution of Formosan Black Bears over the Past Decade

Mei-Hsiu Hwang, He-Jie Shu, Fan-Yi Chan, Chin-Hao Chang, Chia-Chi Wang

Spatial distribution is a key element in assessing the status of wild populations of threatened
species, and can be used to identify priority conservation areas, areas of fragmentation, and
areas of expansion or contraction. We employed the “Assess” component of the Species
Conservation Cycle to evaluate changes in distribution of the endemic, endangered Formosan
black bear (Ursus thibetanus formosanus) on the island of Taiwan. We aimed to compare a
distribution map for 2000–2010 to an updated map based on data collected during 2011–2023.
Since 2011, we collected 1,838 bear presence records (ranging from 202–3,524 m in elevation),
covering 706 1×1 km2 bear grids; 88% were located in natural forest areas, and 58% were
within the protected area system of the Central Mountain Range Conservation Corridor. Bear
presence data collected from camera traps (37%), sign (27%), and sighting reports (15%)
reports showed consistent, widely-distributed patterns; whereas GPS telemetry data (19%) and
bear rescue reports (2%) were limited to some specific areas. We used MaxEnt modeling, using
natural and anthropological variables, to develop the distribution map. The model predicted a
bear range encompassing one-third of the Taiwan area, mainly in the Central Mountain Range.
Distance to protected areas, elevation, and distance to roads were the three most important
factors predicting bear occurrence. Compared to the bear range during 2000–2010, recent data
seemed to indicate a slight expansion, but regional differences were observed. We detected no
recent bear presence or predicted distribution in the Coastal Mountain Range. Bear rescuing
reports (public reports of bears caught in snares near villages) occurred mainly in lower
elevations in a limited area, which may have caused the model to overestimate the range.
Likewise, reports of illegal hunting (a main threat to the population) occurred mainly near
villages, and may have had a similar effect on model predictions. We discuss relevant
conservation and population monitoring strategies stemming from these results.