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. Key Points Unsustainable grazing of small ruminants (SRs; sheep and goats) exerts pressure on the soil and the hydrological processes Hydrological effects of unsustainable grazing are likely to influence quantitative data on runoff process (e.g., runoff coefficient) This review points out the lack of evidence‐based European literature on the impacts of SRs grazing on hydrological processes