New grasslands promote pollination but not biological pest control in nearby arable fields in the short term

Agricultural intensification is a major threat to farmland biodiversity and associated ecosystem services. Semi-natural habitats are integral to the preservation of farmland biodiversity and ecosystem services, however, the extent in which they contribute to specific services is largely unclear. We studied predation rates of ground-dwelling predatory arthropods, and pollination success within old permanent grasslands, newly established grasslands and arable fields near and far from new grasslands. We evaluated whether grassland restoration can enhance pollination and biological control in crop fields. For this purpose, we established new grassland strips within cereal fields, which directly bordered existing permanent grasslands. We evaluated if the distance to these old and new grasslands affects the delivery of the two ecosystem services within crop fields. We found significantly higher seed numbers and seed weight in sentinel plants placed in old grasslands, new grasslands and nearby arable fields compared to distant arable fields. We also found significantly decreasing seed numbers and seed weight in sentinel plants placed in distant arable fields with increasing distance from old grasslands, while pollination success was not affected by distance in nearby arable fields. Contrary, we did not find any significant effects of new grasslands on biological control. Our study showed that 3 years after establishing grasslands arable fields benefited from the proximity of flower-rich new grasslands through increased pollination success though not regarding biological control. This indicates that, on a short term, establishing new grasslands can support beneficial arthropods in providing ecosystem services such as pollination. Predators, in contrast, might take longer to establish effective populations that denote higher predation rates. Our study provides a baseline for future long-term studies to better evaluate pollination and pest control patterns within arable fields.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11829-023-10034-5.

Assessment of determinants of high nature value (HNV) farmland at plot scale in Western Pyrenees

The concept of High Nature Value (HNV) farming hinges on the causality between agroecosystems with low intensity of management and the corresponding environmental outcomes, including high levels of biodiversity and the presence of semi-natural habitats. Although European strategies for rural development and biodiversity conservation have long recognized the importance of HNV farmlands, many of those areas are currently threatened by intensification and land abandonment. A variety of approaches have been developed for identifying HNV areas and measuring changes in their distribution and extent at landscape scales. In contrast, quantitative approaches for evaluating differences in HNV among the most basic units of management (farms and farm plots) are scarce and almost exclusively based on biodiversity indicators. This gap limits our ability to derive existing gradients of HNV at fine scale and the underlying cause conducive to HNV. Hence, we implemented an index to capture multiple facets of HNV based on expert knowledge criteria and field surveys performed at the finest scale of management (plot). First, we computed this index for hundreds of grasslands located across the Western Pyrenees. Then, we analysed the relationship between the nature value of plots and environmental, management and socio-economic variables. Our results evidence a gradient between low diversity and intensively used agricultural plots and HNV grasslands in the Western Pyrenees. Highest nature values were significantly related to the occurrence of plots in meadows located in steep areas within the Natura 2000 network, whereas lowest values were related to recently opened areas and the number of treatments per year. Importantly, this index, which could be adapted to other farming areas, provides quantitative information to support the implementation of result-based schemes, including eco-schemes and agri-environment-climate interventions of the new CAP (2023-2027).

Land sharing complements land sparing in the conservation of disturbance-dependent species

Alteration of natural disturbances in human-modified landscapes has resulted in many disturbance-dependent species becoming rare. Conservation of such species requires efforts to maintain or recreate disturbance regimes. We compared benefits of confining efforts to habitats in protected areas (a form of land sparing) versus integrating them with general management of production land (a form of land sharing), using two examples: fire in forests and grazing in semi-natural grasslands. We reviewed empirical studies from the temperate northern hemisphere assessing effects of disturbances in protected and non-protected areas, and compiled information from organisations governing and implementing disturbances in Sweden. We found advantages with protection of areas related to temporal continuity and quality of disturbances, but the spatial extent of disturbances is higher on production land. This suggests that an approach where land sparing is complemented with land sharing will be most effective for preservation of disturbance-dependent species in forests and semi-natural grasslands.

Facing the future for grassland restoration - What about the farmers?

In line with the 2010 Aichi Convention for Biological Diversity, the European Union has a goal to restore 15% of degraded ecosystems and their services by the year 2020 (target 2, Europe 2020). This includes restoration of semi-natural grasslands (SNGs). Management of both intact and restored SNGs is dependent on people's willingness to manage them. Due to low profitability, management abandonment still occurs all over Europe, which highlights the need to raise farmers' and landowners' perspectives. In this study, we combined survey data and in-depth interviews with farmers/landowners managing previously restored SNGs, to understand how they perceive the restoration process, the outcome and future management. Survey and interview data were analysed in relation to biodiversity and Agri-environmental payments data from the restored sites. Almost all respondents considered the restoration successful and the re-inventoried restored SNGs also showed an increase in plant diversity. Nevertheless, 10% of the restored SNGs were abandoned again post-restoration and 40% of the respondents were unsure if they would continue the management in the future. Abandoned management may cause a negative trend in terms of decreased biological, cultural and aesthetic values, in the local community, as well as for the society in general. Most respondents explained a strong dependency on Agri-environmental payments, both as a restoration incentive and for post-restoration management. Also non-financial support from authorities in form of feedback and advice was requested, as well as support from the local community and society as a whole. Future management in a longer time perspective was strongly coupled to the farm economy, i.e. received Agri-environmental payments at farm-level and profit from selling agricultural products, and whether the farmers had successors. We conclude that both social and ecological factors, here farm economy, authority support and proper management, must be in place for long-term success of grassland restoration.

Divergent Impacts of Two Cattle Types on Vegetation in Coastal Meadows: Implications for Management

The proportion of beef cattle in relation to the total number of cattle has increased in Europe, which has led to a higher contribution of beef cattle in the management of semi-natural grasslands. Changes in vegetation caused by this change in grazers are virtually unexplored so far. In the present study, the impacts of beef and dairy cattle on vegetation structure and composition were compared on Bothnian Bay coastal meadows. Vegetation parameters were measured in seven beef cattle, six dairy heifer pastures, and in six unmanaged meadows. Compared to unmanaged meadows, vegetation in grazed meadows was significantly lower in height and more frequently colonized by low-growth species. As expected, vegetation grazed by beef cattle was more open than that on dairy heifer pastures where litter cover and proportion of bare ground were in the same level as in the unmanaged meadows. However, the observed differences may have in part arisen from the higher cattle densities in coastal meadows grazed by beef cattle than by dairy heifers. The frequencies of different species groups and the species richness values of vegetation did not differ between the coastal meadows grazed by the two cattle types. One reason for this may be the relatively short management history of the studied pastures. The potential differences in grazing impacts of the two cattle types on vegetation structure can be utilized in the management of coastal meadows for species with divergent habitat requirements.

Chemical characteristics of biomass from nature conservation management for methane production

The aim of the current study was to assess the biochemical methane potential (BMP) of different functional groups harvested from different semi-natural grassland types that are valuable for nature conservation purposes. Ensiling of particular biomass did not significantly influence its methane yield, however, the ranking of functional groups by their methane yield varied during the experiment. During the first days of the experiment, methane was released most rapidly by legumes and other forbs with higher N and P contents. At the end of the BMP experiment the quantity of methane produced was higher in grasses and sedges/rushes with lower K, Mg and lignin content. Hence, measurement of feedstock chemical composition is an essential input to develop suitable technology for anaerobic digestion of late harvested biomass from semi-natural grasslands.

Energetic conversion of European semi-natural grassland silages through the integrated generation of solid fuel and biogas from biomass: energy yields and the fate of organic compounds

Twelve European habitat types were investigated to determine the influence of the IFBB technique (integrated generation of biogas and solid fuel from biomass) on the fate of organic compounds and energy yields of semi-natural grassland biomass. Concentration of organic compounds in silage and IFBB press cake (PC), mass flows within that system and methane yields of IFBB press fluids (PF) were determined. The gross energy yield of the IFBB technique was calculated in comparison to hay combustion (HC) and whole crop digestion (WCD). The IFBB treatment increased fibre and organic matter (OM) concentrations and lowered non-fibre carbohydrates and crude protein concentrations. The PF was highly digestible irrespective of habitat types, showing mean methane yields between 312.1 and 405.0 LN CH4 kg(-1) VS. Gross energy yields for the IFBB system (9.75-30.19MWh ha(-1)) were in the range of HC, outperformed WCD and were influenced by the habitat type.