Ecological and economic consequences of using conditioners in grassland mowing
Insect populations are declining in many terrestrial ecosystems worldwide. Permanent agricultural meadows are often mowed for hay production and in addition to the frequency and timing of mowing, farmers have to select mowing machines and decide on specific techniques. The impact of the additional use of mowing conditioners during haymaking has been identified as an important additional threat to insect biodiversity. Conditioners are used immediately after the mowing and mechanically compress the freshly cut grass to allow more evaporation and speed up the drying process of the grass. This compression process increases the physical damage to different arthropod groups during the mowing process. In order to evaluate the impact of the conditioner on different arthropod groups at the landscape scale, it is important to understand to what extent and why farmers implement the conditioner in comparison to other, perhaps less harmful mowing technology. Agri-environment schemes (AES) are a key policy-instrument to incentivize farmers to implement land use and agricultural technologies that are beneficial to biodiversity but costly to farmers. For successful biodiversity conservation, it is important that AES are designed cost-effectively, i.e. in a way that, for available financial resources, species conservation is maximized. Designing cost-effective AES that take into account the impacts of conditioners on insects and the costs of conditioner restrictions in a spatially differentiated manner across regions is not only a complex scientific task, but it can also provide recommendations on the highly policy relevant problem of the design of cost-effective AES.
We address the potential conflict between the use of an innovative mowing technique and the conservation of grassland arthropods by aiming to:
- study the effect of conditioners on the functional diversity and trait composition in arthropod populations and associated ecosystem functions along a grassland management gradient in three Biodiversity Exploratories (BEs).
- estimate costs that occur to farmers if they are faced with restrictions on the use of conditioners differentiated according to management intensities and farming types (extensive and intensive, organic and non-organic) and for the BEs, and
- develop an ecological-economic modelling procedure to design cost-effective AES for mowing regimes with the purpose of insect conservation including mowing regimes with and without restrictions on conditioner use for the three BEs.
H1) We hypothesize that negative effects of the use of conditioners across the three BEs are in the same order of magnitude (15-25% higher damage rates with a conditioner), but that significant additional amounts of variation are explained by overall land-use intensity.
H2) We hypothesize that the negative effects of the use of a conditioner on arthropods, in terms of physical damage to individuals, are stronger in less intensively managed grasslands with (on average) larger species and individuals.
H3) We hypothesize that ecological-economic modelling procedures will allow us to develop a cost-effective AES which takes into account mowing regimes with and without restrictions on conditioners.
H4) We expect the set of cost-effective mowing measures with and without restrictions on conditioners as well as the payments for the different measures to be different depending on management intensities (extensive vs. intensive or organic vs. non-organic farming), the budget size and the three BEs.
As an interdisciplinary project, we apply a range of methods ranging from meta-analyses and ecological field work to agri-economic cost assessment and ecological-economic modelling.
Scientific assistants
