An indicator species approach for result-orientated subsidies of ecological services in grasslands – A study in Northwestern Germany

Abstract

Agri-environmental subsidies for grasslands of high conservation interest are usually associated with fairly strict management rules, but have not always been successful in terms of the preservation of species. A new approach now links the subsidies paid to the ecological value of a grassland site: the farmers are paid for keeping up a high plant species richness, and they can control the species richness of their sites by using vascular plants as indicator species. The method was tested in different grassland communities in six regions of Lower Saxony in Northwestern Germany, mainly addressing the question whether the number of selected indicator species was correlated with the total species richness of vascular plants and with the number of endangered species. Field work was carried out in 2004. Total species richness of vascular plants was recorded in all grassland sites, and the number of indicators was counted along two transects, usually being the diagonals of a rectangular site. Each transect was divided into three segments in which all indicators growing within 1 m distance from the transect line were recorded. In total 43 indicators were selected, mostly representing species that are fairly easy to recognise. The number of indicators was significantly positively correlated with the total number of species in all regions, also when correcting for autocorrelation (except in one region). When using grassland area as a co-variable, the same results were obtained, supporting the low significance of grassland size for the predictive ability of the method. In all regions but one, the mean number of indicators per segment was also significantly positively related to the number of red-listed and near-threatened species in the grasslands. Grassland size and transect length were found to be of minor importance for the application of the method. In conclusion, the study shows that the indicator approach is suitable for identifying those grassland sites that have a high plant species richness and a high number of endangered species. It may thus form the basis for result-orientated subsidies in grasslands.