Hedgerow trees and extended‐width field margins enhance macro‐moth diversity: implications for management

Abstract

Summary1. Improving the effectiveness of agri-environment schemes is essential for reversing declines in farmland biodiversity. Crucial to achieving this is identifying management options that are practical and beneficial to biodiversity, and understanding the influence of the surrounding landscape. We used data on abundance and species richness of farmland macro-moths, many of which are declining, and trait-based analyses on their feeding guild, mobility and conservation status, to explore local-and landscape-scale effects of two farmland features (extendedwidth field margins and hedgerow trees) and surrounding farmland intensification. 2. Macro-moths were light trapped at 48 fixed sites on 16 farms, over 4 years, within a 1200-km 2 area of lowland UK farmland. Sites belonged to one of four experimental groups that differed in their combinations of hedgerow tree presence and field margin width. 3. Hedgerow trees and extended-width field margins locally increased species richness, but not abundance, of macro-moths, irrespective of each other's presence. Overall, species richness and abundance were not affected by agricultural intensification, as measured by the amount of arable land in the surrounding landscape. 4. Sedentary moths showed double the species richness, but were half as abundant as mobile moths. Both groups responded positively to extended-width margin and hedgerow tree presence. The effect of hedgerow trees was particularly strong for shrub-and/or tree-feeding species. 5. Analyses based on the conservation status of moths demonstrated that agricultural intensification lowered the species richness of nationally severely declining UK Biodiversity Action Plan priority species and the abundance of both nationally moderately declining and priority species. These effects were most pronounced at the 0Á8-km radius scale. 6. Synthesis and applications. Our results suggest that the presence of extended-width field margins and hedgerow trees, possibly promoted by agri-environment schemes targeting their implementation at relatively small spatial scales (0Á8 km), may help mitigate negative effects of agricultural intensification on macro-moths. A wide range of other taxa feed on macromoths and may therefore indirectly benefit from these features. Nevertheless, taxa differ widely in their mobility and measures mitigating biodiversity loss may need to be targeted at multiple spatial scales to maximize their effectiveness for multiple taxa.

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Hedgerows surrounding organic apple orchards in north‐west Spain: potential to conserve beneficial insects

“…Apple (Malus x domestica Borkh.) New knowledge on the ecological role of hedgerows with respect to biodiversity conservation or agroecosystem functioning is required to design and implement new policies for the management and protection of these landscape elements (Baudry et al, 2000;Merckx et al, 2012). Consequently, most orchards in the region are focused on cider-apple production .…”

Rewilding European Landscapes

“…data), a macro-moth of which the larvae feed gregariously on blackthorn Prunus spinosa and hawthorn Crataegus sp. In addition, we have recently discovered that the protection of existing hedgerow trees, and the provision of new ones, is likely to be a highly beneficial conservation tool for populations of moths, and probably many other flying insects too, as hedgerow trees provide a sheltered microclimate and other key habitat resources (Merckx et al 2012b). The implementation of hedgerow tree and field margin AES options is likely to provide even better results in areas where farmers are targeted to join AES across the landscape.…”