Wild and domestic animals shape herbivory threats to endangered plants differently

Abstract

In this study, we focus on threatened flora in Spain to analyze the role of various drivers of herbivory in the process by which plants become endangered, attempting to identify patterns in the drivers and threats. Thus, using Hurdle negative binomial regression models, we first test whether herbivory, as a reported threat, is spatially related to its drivers. In the second step, through exploratory data analysis, we study patterns of the herbivory threat in relation to biogeography and conservation factors. Finally, we model the spatial relationships of herbivory to produce a map of hotspots. Our main finding points to wild herbivores, rather than domestic animals, as the major contributors to defining the present spatial distribution of herbivory threatened plants in Spain. Furthermore, we identify the elevation variable as another important factor. Thus, at higher altitudes, there is a correlation between the number of rare plants, high wild herbivores presence, and the existence of protected areas. At present, mountain areas experience conflicts of interest in the conservation of wildlife and rare plants. At the same time, in lower- elevation areas, livestock are no longer concentrated in the lowlands, which reduces direct pressure on rare plants. Accordingly, we propose specific management strategies: for lowland areas, we propose promoting the presence of wild herbivores. At higher altitudes, we propose to use of natural predators as a tool for plant conservation. In the case of Island herbivory, the active removal of non-native animals using negotiation with diverse social groups is necessary.