Impacts of Grazing by Small Ruminants on Hillslope Hydrological Processes: A Review of European Current Understanding

Unsustainable grazing of animals exerts pressure on a range of environmental factors. This review assessed the impacts of grazing of small ruminants (SRs; sheep and goats) on hydrological processes (e.g., runoff occurrence and erosion) within European pasture lands. It also considered other effects of SRs grazing, such as water pollution. Our research highlights the lack of evidence-based European literature on the implications of grazing by SRs on the hydrological processes. The available literature is limited to the Mediterranean belt (some areas of Spain and Greece), the British Isles, and the Austrian Alps. The reasons behind the lack of literature are discussed in detail, and the knowledge gaps dealing with SRs have been enumerated. However, there are several articles on the subject within Oceania-Pacifica and United States settings. Some of the reasons contributing to the limited literature on Europe are the possible underestimation of the significance of the problem, it being considered an unattractive research direction, and/or a lack of research funding. Thus, more research and funding are required to address the European knowledge gaps and limitations related to the impacts of grazing by SRs on the hydrological processes.

Automated summary

This review examined the impacts of grazing by small ruminants on hydrological processes in European pasture lands, finding a lack of evidence-based literature on the subject in Europe. Existing literature is mostly limited to the Mediterranean belt, the British Isles, and the Austrian Alps, while there are studies in Oceania-Pacific and the United States. Underestimation of the problem's significance, it being seen as an unattractive research direction, and a lack of research funding contribute to the limited research in Europe. Further research and funding are needed to address the knowledge gaps and limitations related to the impacts of grazing by small ruminants on hydrological processes in Europe.