Change in black bear range and distribution in Florida using two decadal datasets from 2001–2020

Abstract

AbstractAmerican black bears (Ursus americanus) in Florida have increased in abundance from historically low numbers and currently number >4,000 across 7 subpopulations. Biologists monitor the range of black bears to track their recovery for conservation and management efforts. We estimated geographic range of black bears in Florida for historical (2001–2010) and contemporary (2011–2020) periods using 12 sources of occurrence data collected from wildlife professionals and the public. We reduced data sets by subsampling protocols to account for localized spatiotemporal biases and for possible differences in sampling effort from increases in the human population between modeling periods. We developed models at 2 levels: a generalized boundary (range extent) and a more detailed delineation (occupied range). We developed range extent using a concave hull model and occupied range using kernel density estimation with a corresponding 97.5% isopleth. Between modeling periods, range extent increased by 13.4% and occupied range increased by 11.3%, with both range levels expanding and contracting in certain areas. The ranges indicated improved connectivity among bear subpopulations. We also produced a range map for research, management, and public use built upon contemporary data that partitioned the state into 4 levels representing the relative frequency of bear use (frequent, common, occasional, and rare). Range map levels at the occupied range, and especially frequent use areas, help focus bear research efforts (e.g., placement of hair corrals), management efforts (e.g., assess varying levels of risk to the public of bear conflicts), and conservation efforts (e.g., focusing habitat protection in areas with high use by bears).