Hedgerow rejuvenation management affects invertebrate communities through changes to habitat structure

Hedgerows are an important semi-natural habitat for invertebrates and other wildlife within agricultural landscapes. Hedgerow quality can be greatly affected either by over- or under-management. Neglect of hedgerows is an increasingly important issue as traditional management techniques such as hedgelaying become economically unviable. In the UK, funding for hedge management is available under agri-environment schemes but relatively little is known about how this impacts on wider biodiversity. We used a randomised block experiment to investigate how habitat structural change, arising from a range of techniques to rejuvenate hedgerows (including more economic/mechanised alternatives to traditional hedgelaying), affected invertebrate abundance and diversity. We combined digital image analysis with estimates of foliage biomass and quality to show which aspects of hedge structure were most affected by the rejuvenation treatments. All investigated aspects of habitat structure varied considerably with management type, though the abundance of herbivores and predators was affected primarily by foliage density. Detritivore abundance was most strongly correlated with variation in hedge gap size. The results suggest that habitat structure is an important organising force in invertebrate community interactions and that management technique may affect trophic groups differently. Specifically we find that alternative methods of hedgerow rejuvenation could support abundances of invertebrates comparable or even higher than traditional hedgelaying, with positive implications for the restoration of a larger area of hedgerow habitat on a limited budget. Hecken sind ein wichtiger halbnatürlicher Lebensraum für Wirbellose und andere Wildtiere in der Agrarlandschaft. Ihre Eignung als Habitat kann sowohl durch zu intensives Management als auch durch Vernachlässigung beeinträchtigt werden. Vernachlässigung von Hecken wird mehr und mehr zu einem Problem, da traditionelle Pflegemaßnahmen wie z.B. das “Knicken” wirtschaftlich nicht mehr tragbar sind. Im Vereinigten Königreich stellen Programme zur Förderung umweltgerechter Landwirtschaft Fördermittel für Hecken-Pflegemaßnahmen zur Verfügung, aber wenig ist darüber bekannt, wie solche Maßnahmen sich auf die Biodiversität von Hecken-Lebensräumen auswirken. Ein Block-randomisiertes Experiment diente uns dazu, zu erforschen, wie strukturelle Änderungen durch eine Reihe von Methoden der Hecken-Verjüngung die Häufigkeit und Diversität von