Background information from previous studies 2017-19

The three-year REGRASS project investigated the contribution of newly established ecological compensation areas to promoting the biodiversity of beneficial insects and ecosystem services in agricultural landscapes. To this end, flower-rich meadows (in the form of 10-meter-wide strips of grassland) were created within cultivated fields and managed as meadows by contract farmers. The current project phase focuses on the early colonization history of the newly established meadows by beneficial insects. This involved examining the biodiversity and abundance of spiders, ground beetles, and ants, which make important contributions to pest control, as well as important pollinators such as wild bees, honeybees, bumblebees, and hoverflies. Additional studies were conducted on butterflies, grasshoppers, cicadas, true bugs, and small game. Alongside these organismal surveys, experiments were carried out to assess the effectiveness of the ecosystem services of biological pest control and pollination. Simultaneously, the development of plant growth was monitored by experts from the HBLFA Raumberg-Gumpenstein (a state-run agricultural research institute). Animals, plants, and ecosystem services were studied in newly established meadows, established meadows in the Vienna Woods, and adjacent winter cereals. Animal numbers were also compared between new and old meadows, as well as so-called biodiversity areas (subsidized areas under the Austrian Agri-Environmental Programme). The unique aspect of the REGRASS project lies in the parallel, controlled experimental investigation of a large number of organism groups and ecosystem services. The project results provide information about the initial colonization rate and thus the effectiveness of newly established meadows as ecological compensation areas. The field studies conducted so far, from 2017 to 2019, took place in the area of ​​the Vienna Woods municipality of Sieghartskirchen and describe the initial development phase. The project will now be continued in a long-term study from 2021 to 2023 in collaboration between scientists from the University of Natural Resources and Life Sciences, Vienna (BOKU), and the HBLFA Raumberg-Gumpenstein agricultural college, together with local farmers.

Results 2017-19

Using a regionally adapted seed mixture, species-rich, extensive meadow strips were established on all experimental plots. In the third year of monitoring, these strips contained an average of 25 species of flowering plants from 10 different plant families (Photo 1). Initial results show that pollinating insects quickly accepted these newly established meadows as a foraging habitat and migrated from the surrounding landscape. In some cases, very high numbers of individuals and species were observed in the newly established meadows. Figure 1 illustrates these high numbers of pollinating insects in the new meadows compared to the old meadows and the agri-environmental scheme (ÖPUL) areas. The results demonstrate that promoting a broad spectrum of pollinators requires a correspondingly wide range of flowering plants from different plant families.

Compared to pollinators, colonization by predatory insects proceeded much more slowly. Although the number of species and individuals also increased rapidly in these groups, even after three years the community of spiders, ground beetles, and ants is still essentially that of a field. Although species-specific differences are observable, the newly established meadows have so far hardly served as a compensation area for predatory insects in the sense that species have migrated from the new meadows into the adjacent grain fields. However, the spiders showed a promising shift in distribution within the three years. While the species communities of the new meadows were very similar to those in the grain fields in the first year, in years two and three they shifted away from the grain fields and towards the old meadows, indicating an exchange of species between old and new meadows (Figure 2). Starting from very high individual numbers in the newly established meadows,

Outlook on the REGRASS II project, 2021-23

How long the colonization process by meadow species takes and when a compensation area effectively functions as a new habitat is largely unknown. Likewise, it is unclear when such compensation areas begin to have a measurable effect on ecosystem services. This study is a comprehensive test of the ecological restoration potential of agricultural landscapes. Conducted over an extended period, the results can reveal how quickly and sustainably biodiversity in an agricultural landscape can be stabilized or increased. The project's findings will also provide data on the dispersal potential and speed of insects, thus allowing conclusions to be drawn about their climate change adaptability. Clarifying the aforementioned issues will make a significant contribution to the future design of agri-environmental measures and can provide a sound basis for arguments regarding future agri-environmental schemes and their optimal duration

graphic

Figure 1. Number of wild bees (left), bumblebees (center), and hoverflies (right) in old meadows (OG), newly established meadows (NG), and agri-environmental areas (SG). Different letters indicate significant differences between the habitat types.

 

 

Figure 2. Similarity of spider communities in old meadows (OG=yellow), newly established meadows (NG=green), winter cereals near (CN=blue) and far (CF=red) from NG in the years 2017-2019. Project partners

 

Project partners

University Prof. Mag. Dr. Thomas Frank

Institute of Zoology, University of Natural Resources and Life Sciences Vienna

Dr. Dietmar Moser

Department of Botany and Biodiversity Research, University of Vienna