Mammals show faster recovery from capture and tagging in human-disturbed landscapes

Abstract

Wildlife tagging provides critical insights into animal movement ecology, physiology, and behavior amid global ecosystem changes. However, the stress induced by capture, handling, and tagging can impact post-release locomotion and activity and, consequently, the interpretation of study results. Here, we analyze post-tagging effects on 1585 individuals of 42 terrestrial mammal species using collar-collected GPS and accelerometer data. Species-specific displacements and overall dynamic body acceleration, as a proxy for activity, were assessed over 20 days post-release to quantify disturbance intensity, recovery duration, and speed. Differences were evaluated, considering species-specific traits and the human footprint of the study region. Over 70% of the analyzed species exhibited significant behavioral changes following collaring events. Herbivores traveled farther with variable activity reactions, while omnivores and carnivores were initially less active and mobile. Recovery duration proved brief, with alterations diminishing within 4-7 tracking days for most species. Herbivores, particularly males, showed quicker displacement recovery (4 days) but slower activity recovery (7 days). Individuals in high human footprint areas displayed faster recovery, indicating adaptation to human disturbance. Our findings emphasize the necessity of extending tracking periods beyond 1 week and particular caution in remote study areas or herbivore-focused research, specifically in smaller mammals.

Fig. 1. Methods calculating the disturbance intensity, recovery speed and duration with specific examples.

A Illustrates the difference of daily activity (ODBA) and displacements (days 1–10) from the long-term means (days 11–20). First, we calculated daily (days 1–10) activity (ODBA) and displacements. Subsequently, we related derived values to the long-term mean (days 11–20). The analysis was conducted identically for activity and displacements. B To calculate the disturbance intensity, we related daily averaged values (displacement, activity) to the respective mean during days 11–20. The upper example illustrates the disturbance intensity of Propithecus verreauxi, with increased displacements on the first days, before converging towards the long-term mean; the lower illustrates the disturbance intensity in activity of Canis aureus, with decreased activity during the initial days of tracking. C Recovery speed was calculated as the ∣slope∣ on day one post-release, and recovery duration was determined as the time when animals reverted to their long-term mean for the first time post-release. The upper example illustrates the recovery speed and duration in activity of Cervus elaphus, the lower one of Canis lupus.

Fig. 2. Disturbance intensity: Impacts of collaring on activity and displacements during the initial 10 days post-release.

Daily differences to the long-term mean of activity (upper) and displacements (lower) split by diet: herbivores (left), omnivores (middle), and carnivores (right) for 42 mammal species, n = 1585. All species with p ≤ 0.05 are shown as solid lines and species with p > 0.05 or n < 5 as dotted lines. Activity: R² = 0.374, Dev. explained = 46.4%, displacements: R² = 0.25, Dev. explained = 37.6%. Predictions are derived from two Generalized Additive Mixed Models with Gamma error distributions to assess the effect of disturbance intensity on activity and displacements of the focal species over time. The dotted blue line represents the long-term mean (average for days 11−20). In the legend following each species name, the first number refers to the number of individuals for activity and the second for displacements.

Fig. 3. Recovery speed described in relation to dietary type, an individual’s sex, and the human Footprint index of the study area.

A, B Recovery speed (of activity) described in relation to sex and the Human Footprint index (HFi), n = 1241. High recovery speed values indicate a fast recovery. High HFi values indicate a strong anthropogenic influence, and low values indicate a high degree of remoteness. The inset (A) shows the density plots of the sample size distribution for each dietary guild in regard to HFi. B Predictions are presented for values of the lower (12.37), median (18.68), and upper (25) quartiles of HFi. Insets here (B) present exemplary satellite imagery of sites with differing HFi; left to right: an area with little infrastructure and some habitat fragmentation [HFi: 10]; agricultural fields with small forest patches, road infrastructure, and some settlements [HFi: 17]; a more degraded landscape with a quarry and an adjacent solar park [HFi: 25] (ⓒLandsat / Copernicus, GoogleEarth 2020-2023). Landscapes with extreme HFi values (close to zero: representing pristine, undisturbed areas; close to 50: representing dense populated urban areas) were less present in the dataset and, as such, examples are not shown. C, D Recovery speed (of displacements) described in relation to body mass (C) and dietary type (D), n = 1014. Recovery speed describes the speed of change in activity or displacements as a percentage of the respective long-term mean on day one. Dots (A, C) represent calculated values. Dots (B, D) and the solid lines (A, C) represent mean modeled values, and bars (B, D) as well as the gray shaded area (A, C) are 95% confidence intervals. Note that the y-axis is sqrt-transformed.