Advanced roe deer (Capreolus capreolus) parturition date in response to climate change

In temperate habitats, the vegetation onset in spring affects the life cycle activities of large herbivores. For one species of large herbivore, roe deer (Capreolus capreolus), parturition is tied to peak resource availability. However, recent long-term studies of the parturition date of roe deer found only limited support for its earlier occurrence with an earlier onset of spring. In this study, data from a long-term project (1973–2019) in southern Germany (Baden-Württemberg; elevation 101–1036 m; 16,130 tagged roe deer fawns) were used to investigate whether the advance in the roe deer parturition date reflected different environmental conditions and was thus explained by temporal and spatial factors. Our results showed a consistent advance toward an earlier parturition date (between 0.16 and 0.33 d/yr), especially for elevations above 750 m, that coincided with an advance in plant phenology. Up to 37% of the variance of the detrended time series of the mean annual parturition was accounted for by the detrended time series of the flowering date of forsythia. Our results suggest a plasticity that allows roe deer to cope with climate-induced changes along environmental gradients