High cover of hedgerows in the landscape supports multiple ecosystem services in Mediterranean cereal fields

Abstract

Field-margin diversification through conservation and restoration of hedgerows is becoming a prominent intervention for promoting biodiversity and associated ecosystem services in intensive agricultural landscapes. However, how increasing cover of hedgerows in the landscape can affect ecosystem services has rarely been considered.\ud Here, we assessed the effect of increased field-margin complexity at the local scale and increasing cover of hedgerows in the landscape on the provision of pest control, weed control and potential pollination. Locally, three types of field margin were compared as follows: (i) standard grass margin, (ii) simple hedgerow and (iii) complex hedgerow, along two independent gradients of hedgerow cover and arable land cover in the landscape. We performed an exclusion experiment to measure biological control of cereal aphids and assessed natural enemy and pest abundance in the field. We sampled plant weed communities and performed a phytometer experiment to test the effects of pollinators on plant reproductive success.\ud At the local scale, planting a new hedgerow or improving its structural complexity and vegetation diversity did not enhance the delivery of ecosystem services in the neighbouring field.\ud However, high cover of hedgerows in the landscape enhanced aphid parasitism (from 12 to 18%) and potential pollination (visitation rate and seed set increased up to 70%) irrespective of local margin quality. The cover of arable land in the landscape reduced the abundance of plant-dwelling predators and weed diversity, but did not affect the delivery of the investigated ecosystem services.\ud Synthesis and applications. Our results highlight the key importance of the surrounding landscape context, rather than local factors, to the delivery of ecosystem services. This suggests a need for new policies that pay particular attention to the conservation of hedgerows at large scales for promoting multiple ecosystem services in agroecosystems. Specifically, hedgerows can serve to develop a network of ecological corridors that can facilitate the movement of beneficial organisms, such as pollinators and natural enemies in the agricultural matrix. Such interventions may be a ‘low cost–high benefit solution’, since farmers can create or conserve high-quality habitats taking little or no land from crop production and without the need to change their crop management

Managing trap‐nesting bees as crop pollinators: Spatiotemporal effects of floral resources and antagonists

“…In simplified landscapes where flower-rich habitats have been lost, an effective solution could instead be the adoption of complementary interventions aiming to enhance FRs. The establishment of wildflower strips (Scheper et al, 2015) or hedgerows (Dainese, Montecchiari, Sitzia, Sigura, & Marini, 2017;Dainese, Riedinger et al, 2017;Morandin & Kremen, 2013) is, for instance, a simple strategy to create high-quality habitats taking little or no land from crop production. These interventions should be targeted at providing continuous bloom over the season for supporting the greatest diversity of wild pollinators (Scheper et al, 2015;Williams et al, 2015;Wood, Holland, & Goulson, 2017).…”

Spatial diversification of agroecosystems to enhance biological control and other regulating services: An agroecological perspective

“…Nevertheless, several recent studies did not report an increased diversity of flower-visiting insects with such a mixture, recalling that a high functional diversity at the mixture level does not necessarily enhance insect diversity (Balzan et al, 2014(Balzan et al, , 2016aHatt et al, 2017c;Uyttenbroeck et al, 2017). At the landscape scale, however, the increased density of flowering features such as hedgerows showed a positive effect on pest control by parasitoids and pollination (Dainese et al, 2017).…”

“…Finally, Sarthou et al (2014) observed that the local habitat structure (especially of grass strips), rather than landscape complexity, affects abundance of a diversity of natural enemies at emergence (i.e. after overwintering period) while Dainese et al (2017) reported that the increased cover of hedgerows at the landscape scale increased aphid parasitism independently from margin diversity at the local scale. This variability of results in the interaction between local and landscape scales may be explained by the diversity of natural enemies, pests and crops studied.…”

Quantification of olive pomace availability for biogas production by using a GIS‐based model

“…physiographic units, landscape units, geomorphologic units, geological units, iso‐slope zones, agricultural units, and road‐bounded areas), in this model the discretization methodology based on administrative boundaries makes it possible to obtain data from databases of agricultural production or other supports, such as regional technical maps and ortho‐photo images. Image processing for the classification of high‐resolution satellite images could also be used for this purpose …”