Population-level effects of wildlife rehabilitation and release vary with life-history strategy

Abstract

Wildlife rehabilitation is the treatment and subsequent release of injured wildlife. Wildlife rehabilitation benefits individual animals receiving care, but also supports Conservation Medicine approaches by providing opportunities to monitor wildlife health, contaminant loads, and disease prevalence. However, it is typically considered to have negligible effects on population growth, and has not traditionally been acknowledged as an effective tool for wildlife conservation. To explore whether rehabilitation and release could directly support population recovery in some cases (i.e., increase population growth rates), we considered five case study species along a spectrum of life-history strategies (Raccoon, Painted Turtle, Blanding’s Turtle, Snapping Turtle, and Little Brown Bat). We simulated populations over 200 years, while varying two parameters: 1) the rate of severe injury (0, 1, 2, or 5 % of the population); and 2) how many of these injured animals are successfully rehabilitated (0, 10, 25, or 50 %). The effect of the rehabilitation scenarios was largest when additive severe injury rates were highest (5 %). Species that were most sensitive to increased adult injury rates (turtles and bats) also exhibited the greatest population-level responses to rehabilitation and release interventions. We conclude that wildlife rehabilitation can support in situ recovery and help stabilize declining populations when 1) injury is an ongoing source of high additive mortality, 2) the target population is small, 3) the species exhibits a K-selected life-history strategy, 4) rehabilitation can be combined with other interventions, including in situ threat mitigations, and 5) rehabilitation efforts do not jeopardize or limit in situ conservation interventions.