Green-up selection by red deer in heterogeneous, human-dominated landscapes of Central Europe

The forage maturation hypothesis [FMH] assumes that herbivores cope with the trade-off between digestibility and biomass in forage by selecting vegetation at intermediate growth. The green wave hypothesis [GWH] extends the FMH to suggest how spatiotemporal heterogeneity in plant quality shapes migratory movements of herbivores. Growing empirical support for these hypotheses mainly comes from studies in vast landscapes with large-scale habitat heterogeneity. It is unclear, however, to what extent ungulates surf green waves in human-altered landscapes with small-scale heterogeneity in terms of land use and topography. We used plant phenological proxies derived from Sentinel 2 satellite data to analyse the habitat selection of 93 collared red deer [Cervus elaphus] in montane and alpine habitats. Using a step selection analysis, we investigated how plant phenology, i.e. the instantaneous rate of green-up [IRG] and normalised difference vegetation index [NDVI], and a set of variables descr...