Displacement Effects of Conservation Grazing on Red Deer (Cervus elaphus) Spatial Behaviour

Abstract

Conservation grazing uses semi-feral or domesticated herbivores to limit encroachment in open areas and to promote biodiversity. However, we are still unaware of its effects on wild herbivores. This study investigates the influence of herded sheep and goats on red deer (Cervus elaphus) spatial behavior by testing three a-priori hypotheses: (i) red deer are expected to avoid areas used by livestock, as well as adjacent areas, when livestock are present, albeit (ii) red deer increase the use of these areas when sheep and goats are temporarily absent and (iii) there is a time-lagged disruption in red deer spatial behavior when conservation grazing practice ends. Using GPS-telemetry data on red deer from a German heathland area, we modelled their use of areas grazed by sheep and goats, using mixed-effect logistic regression. Additionally, we developed seasonal resource selection functions (use-availability design) to depict habitat selection by red deer before, during, and after conservation grazing. Red deer used areas less during conservation grazing throughout all times of the day and there was no compensatory use during nighttime. This effect mostly persisted within 21 days after conservation grazing. Effects on habitat selection of red deer were detectable up to 3000 meters away from the conservation grazing sites, with no signs of either habituation or adaption. For the first time, we demonstrate that conservation grazing can affect the spatio-temporal behavior of wild herbivores. Our findings are relevant for optimizing landscape and wildlife management when conservation grazing is used in areas where wild herbivores are present.

Keywords: Dry grassland; Habitat selection; Heathland conservation; Resource selection functions; Targeted grazing; Wildlife.

Fig. 1

Map of the Glücksburger Heide study area in Saxony-Anhalt; the three conservation grazing sites are indicated by black lines. Borders of the DBU-managed Natural Heritage area are marked with black-dotted lines

Fig. 2

Effects of the different treatments during winter (left) and summer (right) on the direct use of the grazing sites as estimated by logistic regression. The y-axis represents the probability of use by red deer

Fig. 3

Predicted selection for distance to grazing sites during summer (left) and winter (right) during the day. The x-axis represents distance to the conservation grazing site (meters), and relative attractiveness is shown on the y-axis. For visualization purposes, scores produced by the RSF were scaled by dividing them by the scenarios-specific median

Fig. 4

Maps of the study area depicting the spatial distribution of RSF scores before conservation grazing (left) and during the later stages of conservation grazing (right) during the summer and in the daytime