1994; Forbes and Hodgson 1985; Fraser et al. 2007). Co-grazing may also lead to increased daily liveweight gains of both animal species SN-38 purchase involved (Nolan and Connolly 1989). A combination of species in co-grazing may lead to the development of a more uniform sward with respect to height. However, due to the distinct effects on plant species by selective grazing, treading and excretion,

the underlying heterogeneity might be larger with co-grazing, allowing the creation of more diverse niches. To sum up, grazing is regarded as a most efficient way of utilizing and maintaining less intensive and semi-natural grasslands. However, the interactions of soil and site characteristics, hydrology, plant communities, and grazing management are complex and the situation check details is often further complicated by restrictions in grazing time, nutrient return and market demands. A thorough understanding of the grazing process will help to properly address the problems

arising in a specific environmental/agricultural/socio-cultural context and to combine benefits of extensive grazing concepts for improved or maintained biodiversity, landscape scenery, soil protection and farm income (Soder et al. 2007). In order to achieve these tasks, it is likely that management restrictions Cl-amidine need to be adapted to local conditions, especially by adjusting grazing intensity to productivity, by allowing some form of nutrient return or by mulching, to avoid cases where the process of selective grazing might lead to abandonment of parts of the pasture. In a complex situation like extensive grazing what may be beneficial for one objective may have damaging consequences for another (Mills et al. 2007). Discussion Farmers and ecologists have contrasting ideas about the usefulness of biodiversity for grassland production. As outlined above, these seem to be based on contrasting experiences in different environments: experiments have often been conducted in experimental grassland plots or newly sown grassland where PtdIns(3,4)P2 the vegetation composition

is not (yet) in equilibrium with the resources, where management and harvests are rarely comparable with agricultural situations and where the focus is on primary production. In contrast, in low to moderate management situations the farmer is dealing with permanent grasslands comprising species numbers that are in dynamic equilibrium with the environment and is engaged in the sometimes difficult task of matching primary production with the needs of the animals. Results from experimental grassland plots may still have implications for agricultural systems managed in a way similar to these plots, e.g. in ley farming. Here, the growing of cash crops is alternated with legume or grass pastures. The grassland species are sown in and the pasture is kept for a few years to increase soil fertility and disrupt pest cycles before it is ploughed for another round of cash crops.