Temperature-driven river utilisation and preferential defecation by cattle in an English chalk stream

Cattle have the potential to be important geomorphic and ecological agents in the low-energy, high biodiversity chalk rivers of southern England. To improve our understanding of cattle-river interactions, a unique high temporal resolution study of cattle behaviour and distribution was conducted across 500 h on a chalk river in Hampshire, England (UK) between April and October 2010. It was observed that cattle spent approximately 2% of their time in the aquatic environment and approximately 7% of their time in the riparian zone. Cattle activity and distribution varied according to the time of day and the time of year. A statistically significant correlation was recorded between the amount of time spent in-stream by cattle and air temperature. Cattle also defecated five times more frequently in-stream than the average defecation frequency, contributing greater than expected direct organic matter and nutrient inputs. The study suggests that the impacts of cattle in chalk river environments may have been underestimated, particularly at a time of global warming.