Farmland biodiversity: wildflower-sown islands within arable fields and grassy field margins both promote spider diversity

Agricultural intensification and the concomitant landscape homogenization is leading to a worldwide decline in farmland biodiversity. Non-crop habitats in agroecosystems may counteract the loss of arthropods such as spiders and thus contribute to sustainable agriculture. However, the effectiveness of field margins and set-aside wildflower-sown patches in maintaining spider diversity is not well understood. Here, we investigated the effects of three different non-crop habitats, namely field margins, set-aside wildflower-sown patches under power poles (‘power pole islands’), and grassland fallows on spider diversity as compared to wheat fields in an agricultural landscape in western Germany. Using pitfall trapping and suction sampling, we show that species richness and overall conservation value were higher in non-crop habitats than in wheat fields. Interestingly, field margins and power pole islands differed from long-term grassland fallows only in conservation value, which was significantly higher in grassland fallows. Species assemblages differed considerably between grassland fallows, field margins and power pole islands, and wheat fields, documenting the added value of using different conservation strategies. Implications for insect conservation Small-scale non-crop habitats adjacent to wheat fields were surprisingly effective in promoting spider diversity in an agricultural landscape, with field margins and power pole islands being equally effective. To maximize overall diversity in agricultural landscapes, we propose a combination of larger long-term fallows and smaller non-crop habitats such as field margins or set-aside wildflower-sown patches.

Hotspots of Agricultural Ecosystem Services and Farmland Biodiversity Overlap with Areas at Risk of Land Abandonment in Japan

Agriculture provides a wide range of ecosystem services and has the potential to contribute to biodiversity conservation. In Japan, many of the resources associated with agroecosystems are threatened by farmland abandonment. Identifying where and to what extent agricultural ecosystem services and farmland biodiversity are affected by farmland abandonment is essential for developing effective strategies to counter the potential loss of these services and the biological communities that support them. Our study aimed to examine how a set of indicators for ecosystem services and biodiversity linked to agroecosystems (proportions of land dedicated to rice production and other agricultural production, proportion of agricultural land on slopes potentially providing landscape aesthetics, proportion of villages promoting rural tourism, and densities of forest edges and irrigation ponds in agricultural land) are distributed at the municipal level across the Japanese Archipelago, and to analyze their spatial patterns in relation to the distribution of farmland abandonment. It was hypothesized that hotspots of agricultural ecosystem services and farmland biodiversity occur in areas at risk of farmland abandonment owing to shared drivers. The cluster analysis identified four distinct ecosystem service bundle types, two of them representing areas specializing in agricultural production, while the other two provided high levels of cultural services and habitats for diverse biological communities. The latter two bundles were located in hilly and mountainous areas and accounted for 58% of rice production, 27% of other agricultural production, 77% of landscape aesthetics, 77% of rural tourism, 64% of forest edges, and 87% of irrigation ponds in Japan. In support of the hypothesis, farmland abandonment was pronounced in these areas, with 64% of recently abandoned fields located where 44% of agricultural land was found. This spatial overlap suggests that substantial losses of ecosystem services and biodiversity may occur if current patterns of farmland abandonment continue. In order to prevent large-scale losses of agricultural ecosystem services and farmland biodiversity, measures to counteract the ongoing abandonment trends should prioritize hilly and mountainous areas, and future studies should further evaluate the multiple functions of agricultural areas to improve policies that aim to ensure sustainable development of rural areas in Japan.

Effects of hedgerow enhancement as a net zero strategy on farmland biodiversity: a rapid review

In order to mitigate the effects of climate change, the UK government has set a target of achieving net zero greenhouse gas (GHG) emissions by 2050. Agricultural GHG emissions in 2017 were 45.6 million tonnes of carbon dioxide equivalent (CO2e; 10% of UK total GHG emissions). Farmland hedgerows are a carbon sink, storing carbon in the vegetation and soils beneath them, and thus increasing hedgerow length by 40% has been proposed in the UK to help meet net zero targets. However, the full impact of this expansion on farm biodiversity is yet to be evaluated in a net zero context. This paper critically synthesises the literature on the biodiversity implications of hedgerow planting and management on arable farms in the UK as a rapid review with policy recommendations. Eight peer-reviewed articles were reviewed, with the overall scientific evidence suggesting a positive influence of hedgerow management on farmland biodiversity, particularly coppicing and hedgelaying, although other boundary features, e.g. field margins and green lanes, may be additive to net zero hedgerow policy as they often supported higher abundances and richness of species. Only one paper found hedgerow age effects on biodiversity, with no significant effects found. Key policy implications are that further research is required, particularly on the effect of hedgerow age on biodiversity, as well as mammalian and avian responses to hedgerow planting and management, in order to fully evaluate hedgerow expansion impacts on biodiversity.

Biodiversity in agricultural landscapes: different non-crop habitats increase diversity of ground-dwelling beetles (Coleoptera) but support different communities

Agricultural intensification poses a major threat to the conservation of biodiversity and associated ecosystem services. Since non-crop habitats are regarded as important refuges for farmland biodiversity, various greening measures have been proposed to halt biodiversity loss. However, the effectiveness of these measures for biodiversity conservation is still under debate. Therefore, we here compared ground-dwelling beetle (Coleoptera) assemblages of different non-crop habitats (field margins, set-aside fields sown with wildflowers, and permanent grassland fallows) and wheat fields within an intensively used agricultural landscape in western Germany. Taxonomic diversity of Carabidae, Staphylinidae and other coleopteran families and their conservation value were higher in all non-crop habitats than on wheat fields. Surprisingly, though, different types of non-crop habitats did not differ in species richness or the number of threatened species. Thus, field margins and sown wildflower fields were as effective in promoting beetle diversity as grassland fallows. However, different non-crop habitats supported different species assemblages, and several species, in particular especially large ones, were restricted to grassland fallows. These results suggest that different greening measures are effective in promoting the biodiversity of beetles, and that permanent grassland fallows are essential for nature conservation. The fact that habitat types harbored different assemblages stresses the need to combine a variety of greening measures to yield the highest benefit for biodiversity.

A Rapid Method for Monitoring Landscape Structure and Ecological Value in European Farmlands: the LISA approach

Farmland biodiversity has dramatically declined in European agricultural landscapes over the past century. The key driver of this decline is the intensification of farming practices. In response, various policies have been developed to protect and promote farmland biodiversity, including so-called greening measures under the Common Agricultural Policy(CAP). However, there is currently very little systematically collected data on the ecological quality of European farmland. Therefore, we developed a survey method to provide repeatable and comparable data. This method comprises the mapping of land use and ecological quality of parcels in sample plots of 500 m x 500 m, vegetation transects on up to four predefined parcels in each sample plot and a photo documentation of the transects and the whole plot. Using this LISA method (Landscape Infrastructure and Sustainable Agriculture), we investigated about 25plots in each of 35 regions in 2014 and 13 regions in 2016, altogether in 10 EU countries. The methodology provides a time- and cost-efficient possibility to collect standardised data on the ecological quality of farmland habitats. We show that biodiversity in arable fields is at an extremely low level. The survey methodology proved to be applicable in all parts of Europe and thus being applied widely it could deliver a representative view on the ecological situation of all agricultural landscapes in Europe.