Agroscope, Institute for Plant Production Sciences IPS, 1260 Nyon, Switzerland

Influence of management practices and landscape location on ground dwelling spiders in wild flower strips

With the growing interest for wildflower strips in Switzerland, the questions of their management and optimal location become relevant. At one site (in Wermatswil ZH), we studied the impact of two different management practices (mowing and mulching) on spider populations. At the other site (in Rafzerfeld ZH), the influence of several environmental factors (structure and location of five wildflower strips) on spider populations were investigated. No significant influence on species composition of ground dwelling spiders due to different management practices could be detected. However, management practices had a positive impact on numbers of individuals per species. Therefore, cutting or mulching of wildflower strips early in the year does not negatively influence species composition and can be positive for the activity of ground dwelling spiders. Of thirteen environmental factors under investigation, only the distance to the forest and the percentage of litter coverage were found to be significantly correlated with the distribution of the spider populations. These two factors are in particular important if we want to understand the colonisation and distribution of airbone species like the linyphiids and the activity of wolf spiders, which are dependent on obstacles in the vegetation.

To the archive