Effects of management on vegetation structure in horse pastures.

Horses are known to create and maintain heavily grazed short patches within a matrix of avoided tall patches. However, there is little systematic research in horse pastures under practical farming conditions. Data on grassland management were recorded for 70 horse- farms in Germany. Soil-chemical factors, species richness and cover were measured for short and tall patches (each 25 m²) within 280 sites. We found distinct differences in soil nutrient concentration and species composition between short and tall patches. This heterogeneity within sites was found to enhance plant diversity at paddock scale. Stocking methods as well as sward maintenance measures affected heterogeneity and plant species composition.