AUTHORS: Nathan Ranc, Department of Organismic and Evolutionary Biology, Harvard University, and Department of Biodiversity and Molecular Ecology - Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’ Adige, Italy; Paul Moorcroft, Department of Organismic and Evolutionary Biology, Harvard University; Tobia Sforna, Department of Biodiversity and Molecular Ecology - Research and Innovation Centre, Fondazione Edmund Mach, Italy, and Life Science Department, University of Trieste; Whitney Hansen, Department of Organismic and Evolutionary Biology, Harvard University; Federico Ossi, Department of Biodiversity and Molecular Ecology - Research and Innovation Centre, Fondazione Edmund Mach, Italy; Priscilla Bonanni, Department of Biodiversity and Molecular Ecology - Research and Innovation Centre, Fondazione Edmund Mach, Italy, and Department of Biology and Biotechnology ‘Charles Darwin’, University of Rome ‘La Sapienza’, Italy; Alessandro Brugnoli, Enrico Ferraro – Associazione Cacciatori Trentini, Italy; Francesca Cagnacci, Department of Organismic and Evolutionary Biology, Harvard University, and Department of Biodiversity and Molecular Ecology – Research and Innovation Centre, Fondazione Edmund Mach, Italy
ABSTRACT: The supplementary feeding of ungulates, which is widespread across North America and Europe, typically seeks to improve individual and population performance, compensate for the loss of habitat, and improve hunting opportunities [1]. However, despite its prevalence as a management strategy, this practice can have significant impacts on individual movement and space-use patterns [2]. We aimed at evaluating the behavioral and spatial response of European roe deer (Capreolus capreolus) to spatiotemporal dynamics in supplementary feeding management. To address this question, we captured and tagged nine individual roe deer with GPS collars in an area with supplementary feeding (Eastern Italian Alps). We monitored the availability of food at the feeding stations on a weekly basis from January to May to obtain a temporal classification of feeding site management into two states: active (available feed) or inactive (unavailable). We examined each individual’s space-use patterns in relation to temporally-dynamic food availability at intensively attended, focal feeding sites. We computed three metrics of space-use in subsequent alternate periods of food provisioning at focal feeding sites: home range size (95% multiple convex polygon, MCP), and spatial overlap and centroid distance between subsequent home range cores (50% MCP). Furthermore, we investigated the periodicity of movement recursions towards feeding sites using spectral analysis. For each existing feeding site, we generated a presence- absence (P/A) time series using a 50 m buffer. Individual feeding site time series were then aggregated based on management status to obtain both active and inactive feeding site P/A time series. We conducted two Fourier analyses on active and inactive time series to assess landscape-level response to management, and a wavelet analysis on focal feeding site time series to evaluate temporal patterns in periodicity [3].
The home range size was unaffected by feeding site management (active: mean = 46.78 ha,
CI = 18.01 - 71.55; inactive: mean = 45.70 ha, CI = 32.67 - 58.73; paired t test: t = -0.10, df = 8, p-value = 0.92, n = 9). However, management influenced the location of the home range core: successive home range cores barely overlapped (mean = 20%, CI = 0 - 42%) and were relatively distant (mean = 284 m, CI = 145 - 422 m). Roe deer recursions showed a consistently clear peak at 24-h periodicity for active feeding sites, whereas this characteristic circadian signal was weak or absent for inactive sites (Fig. 1). In addition, disruptions of recursions towards focal feeding sites were consistently observed following supplementary feed depletion (Fig. 2). Our results suggest that roe deer shift space-use in response to spatiotemporal dynamics in supplemental resource availability. Specifically, we found a reallocation of movement and home range cores towards active feeding sites, and a temporary decline in movement recursions towards inactive sites. These findings are concordant with previous studies demonstrating a high plasticity in feeding site use of the European roe deer [4], as well as space-use implications of supplemental feeding [5].
