The interplay of landscape composition and configuration: new pathways to manage functional biodiversity and agroecosystem services across Europe, Martin et al. 2019

This paper analyzes 49 studies (1515 landscapes encompassing both organic and conventional agricultural production) in Europe to determine “effects of landscape composition (% habitats) and configuration (edge density) on arthropods^[7] in fields and their margins, pest control, pollination and yield” [Martin 2019: 1].

Edge density is measured as the length of edge per area of land. Edges between adjacent crop fields and between crop fields and semi-natural areas such as grasslands or other land patches not used for crops allow for “exchange between landscape patches” [Martin 2019: 4] for pollinators, pest predators and other providers of ecosystem services. High edge density is associated with smaller field size, and lower edge density with larger field size.

Complex landscapes where small and/or irregularly shaped fields and habitat patches prevail have a high density of edges. Due to increased opportunities for exchange, these landscapes are likely to support spillover of dispersal-limited populations between patches [Martin 2019: 3].

Researchers found that:

In landscapes with high edge density, 70% of pollinator and 44% of natural enemy species reached highest abundances and pollination and pest control improved 1.7- and 1.4-fold, respectively. Arable-dominated landscapes with high edge densities achieved high yields. This suggests that enhancing edge density in European agroecosystems can promote functional biodiversity and yield-enhancing ecosystem services [Martin 2019: 1].

Just as high edge density is shown here to maintain yield, low edge density, especially when combined with a lower amount of surrounding semi-natural habitat, can reduce yield.

Reduced pollination and pest control at low edge density may have been compensated by external inputs in productive landscapes. … Intermediate to low yields in landscapes with high % arable, low % semi-natural habitat and low edge density may underpin the risks of ongoing conventional intensification resulting in yield stagnation or reduction despite high agricultural inputs [Martin 2019: 9].

This article illustrates the important role of ecosystem services in maintaining crop yield, as well as the relatively simple management decisions farmers can make to enhance the habitat of arthropods providing those services.