Resource selection at fine-scale: What drives the decision of a generalist herbivore?

Abstract

Spatial patterns in topography and forage distribution significantly influence the movements and choices of large herbivores. However, understanding the foraging strategies of free-grazing herbivores at different temporal and spatial scales remains limited, as different behavioural decisions can apply at different hierarchical levels, This study investigates the fine-scale foraging strategies of zebra (Equus quagga) in a South African savanna, with a specific focus on their selection of green vegetation at the plant and feeding patch levels. We used the Normalized Difference Vegetation Index (NDVI) as a proxy for vegetation productivity and quality. Our findings reveal that zebra adapted their foraging strategies according to the scale and season. During the late-dry season and early-wet season, selection for greenness was at both the grass tuft and feeding site levels. In contrast, during the mid-dry season, their selection was predominantly at the tuft level, focusing solely on greenness. These insights emphasize the importance of conducting multi-level studies when investigating factors influencing foraging decisions. Findings at one hierarchical level may not necessarily apply across other levels of investigation, highlighting the need for a nuanced and comprehensive approach to understanding the complex foraging behaviours of these animals.