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Recommended by C. Geron and C. F. J. Meyer
School of Applied Sciences, Bournemouth University, Talbot Campus, Fern-Barrow, Poole, Dorset BH12 5BB, UK
Received 9 August 2011; Accepted 15 September 2011
1. Introduction
The restoration of lowland heath is an important facet of heathland conservation, as restored heathlands can ameliorate the effect of habitat fragmentation and so reduce the risk of extinction debt [1]. Much heathland has been destroyed through agricultural intensification during the second half of the last century [2, 3]. Consequently, there has been considerable long-standing interest in methods for the restoration of heathland on improved agricultural land [4-14]. Such restoration requires a reversal of the increased soil pH and nutrient availability that is effected during agricultural improvement so that ericaceous and acid grassland species are not outcompeted by large-growing mesotrophic grasses. Successful approaches have been based on either physically removing the improved topsoil [15, 16] or chemically amending it by, for example, adding sulphur to reduce pH and macronutrient concentrations [17, 18].
Whilst it is encouraging that some heathland restoration attempts based on either soil removal or soil acidification are successfully establishing ericaceous covers, the evaluation of successful habitat restoration should encompass a far broader assessment of the extent to which the communities and ecological processes of the restored ecosystems show similarity with those of target, established ecosystems [19]. This is particularly true for heathland restoration, as an important aim is often to provide habitat for higher trophic level protected species such as stone curlew ( Burhinus oedicnemus ), nightjar (Caprimulgus europaeus ), and sand lizard (Lacerta agilis ) that can have significant parts of their life cycles associated with heathlands. Key factors for all these species are appropriate vegetation structure and composition and the availability of surface dwelling invertebrate prey. For example, stone curlew nest on open land including grass heaths and chicks usually forage within 100 m of their nest for surface-active invertebrates such as beetles, woodlice, molluscs, and worms [20, 21]. Beetles have been shown to constitute approximately a third of the diet of stonechat chicks with ground beetles alone accounting for a fifth of the total diet; hymenoptera and spiders were also found to be important elements [22]. The availability of invertebrate prey has also...