Intensification of agriculture in the EU has boosted yield, food security and food quality, contributing to economic development and human well-being. On the other hand, land abandonment and intensification have resulted in a strong decline of farmland biodiversity. Seventy-six per cent of the Habitat Directive habitats linked to agro-ecosystems and 70% of the Habitat Directive species linked to agro-ecosystems have an unfavourable conservation status. In addition, the impact of agriculture on the ecosystem is often detrimental: nutrient surpluses and pesticides contaminate the surface water, intensive agricultural practices have led to soil degradation, compaction and erosion and agricultural activities account for 10% of total European greenhouse gas emissions. In order to put an end to further biodiversity losses and environmental degradation, measures have been proposed, for example in the European Common Agricultural Policy. These measures – in this research called nature-oriented measures – include the introduction of semi-natural elements and the inclusion of ecological principles in agricultural practices. It is expected that the costs related to nature-oriented measures will negatively affect farm income. Because most farmers already face economic challenges, it is crucial that the implementation of nature-oriented measures is effective and cost-efficient and that the efforts of the farmers are properly and fairly compensated.

Optimal implementation of nature-oriented measures requires insight into the simultaneous effects that can be expected, both on crop yield (a provisioning ecosystem service) and farm income as on the delivery of regulating and cultural ecosystem services and on biodiversity. The impact of a number of these measures on ecosystem services and biodiversity has already been studied, but generally within one study only one (or several related) response variables are evaluated at the time. Assessing multifunctionality by combining studies that focus on only one response variable may lead to overestimation of effects because monitoring sites are often selected to demonstrate a maximal impact of a measure on a specific response variable. Therefore, there is a need for research that considers multiple ecosystem service and biodiversity indicators simultaneously.

In this study, we assessed the simultaneous impact of three types of nature-oriented measures on one provisioning and multiple regulating ecosystem services and on biodiversity components. These nature-oriented measures include the implementation of i) hedgerows and ii) grass strips on arable field borders as well as iii) the extensification of grassland management. Crop yield, both biomass and quality, was the provisioning service and the regulating services that were considered are global climate regulation, chemical quality regulation of both surface and subsurface water, erosion regulation and natural pest control. Indicators for these regulating ecosystem services are respectively soil organic carbon sequestration, the interception of nitrogen and phosphorus from the surface and subsurface flow, the interception of soil particles from the surface water and the presence of natural predators. The considered indicators for biodiversity are the species number and species composition of plants and carabids.

By means of a meta-analysis, we quantified the effect relationship between hedgerow and grass strip characteristics and ecosystem service and biodiversity. Close to the hedgerow, until a distance of about twice the hedgerow height, crop yield was reduced by 21%, most probably as a result of competition for light and nutrients, and beyond this point until a distance of about 20 times the hedgerow height, crop yield was increased by 6%, potentially as a result of an improved microclimate. Near the hedgerow, until a distance of about four times the hedgerow height, soil organic carbon stock was increased by 8% compared to a parcel without a hedgerow. Also in the grass strip, soil organic carbon was 25% higher compared to the adjacent parcel. Both hedgerows and grass strips improved the water quality by the interception of nitrogen from surface (69% for

hedgerows, 76% for grass strips) and subsurface (34% for hedgerows, 32% for grass strips) water, phosphorus from the surface water (67% for hedgerows, 73% for grass strips) and reduction of erosion (91% for hedgerows, 90% for grass strips). Hedgerows increased the number of predator species, but not predator abundance. On parcels with grass strips, both the number of predator species and predator abundance were increased. Parcel-level estimations show that the trade-offs between provisioning and regulating ecosystem services and biodiversity primarily depend on dimensions of the hedgerow, grass strip and parcel.

Next, we monitored a set of ecosystem service and biodiversity indicators on arable parcels in Flanders with a hedgerow or grass strip along at least one of the field borders. Near the hedgerow, crop yield was reduced and thousand grain weight, soil organic carbon stock and activity-density of spiders were increased compared to further in the field. In the grass strip, soil organic carbon stock was increased, soil mineral nitrogen content was reduced and we found a different carabid species composition and higher spider activity-density, compared to the adjacent parcel. We concluded that hedgerows and grass strips have the potential to deliver a broad set of ecosystem services and to enhance biodiversity, but that this potential is not always realized, among other as a result of local management.

Additionally, we assessed the effect of grassland management type and intensity on ecosystem service delivery and biodiversity. The considered management types were regular, intensive management, meadow bird management and botanical management. Yield, crude protein content and soil mineral nitrogen content were higher in the regular, intensively managed grasslands. The number of plant species was higher in the more extensively managed meadow bird and botanical grasslands. From a literature review, we derived the same effect relationship between management intensity and ecosystem service and biodiversity indicators, but additionally, we found a positive impact of animal fertilizer application on soil organic carbon stock.

Finally, we developed a calculation tool that allows the prediction of income losses related to the implementation of nature-oriented measures, both at parcel and at farm level. Our results were integrated in the tool in order to estimate the effect of nature-oriented measures on income loss, ecosystem services and biodiversity at farm level. We concluded that the agricultural landscape has the potential to contribute to a wide range of services, but this requires the uptake of nature-oriented measures in the farm management. We end by formulating recommendations for further research, management and policy.