Securing Biodiversity in Breckland - European Commission

Management Recommendations for Priority Assemblages in Grass-Heath HabitatsIn this section we examine the ecological requirements of species in a range of grass-heath habitatsincluding dune, heath, grass-heath, scrub and woodland ecotones and propose techniques to providethese conditions.Graze hardIn view of the ecological requirements of characteristic stress-tolerant Breckland plant specialiststhat are mostly intolerant of competition in a closed sward, it is recommended that grazed sitesshould be grazed hard and intensively. This is particularly relevant in face of nitrogen deposition.However, grazing should not be entirely homogeneous and uniform across sites. Evidence fromBrettenham Heath shows that grazing of short closed swards appears consistent with creatingconditions required by a range of stress-tolerant invertebrates of litter, upper saltmarsh and littoralmargins.However, grazing on its own is not sufficient. It is also important to provide bare ground, broken turf,sward mosaics and a complex juxtaposition of habitats, to provide the conditions required by otherassemblages of priority species for Breckland conservation (see below).Do not be constrained by heather when revising grazing regimesThe presence or otherwise of heather on a site should not be a constraint or objective of sitemanagement. Heather is not particularly important in a Breckland context.The number of Breckland conservation priority species which are obligates of Calluna and Erica isgenerally few. Exceptions include the leaf beetle Altica ericeti, which is phytophagous on the foliage.Heather is important for the heath rustic Xestia agathina, neglected rustic Xestia castanea andshoulder-striped clover Heliothis maritima moths that all feed primarily on Calluna in Breckland.Species associated, but not obligates of heather, include the RDB fly Myopa fasciata, which is aparasite of mining bees and is associated with Calluna.Heather is useful as a late and long lasting pollen and nectar source for Hymenoptera and someLepidoptera species, but this can be provided by heather plants in a pioneer state. At very low patchydensities it can also help provide a heterogeneous structure, particularly suitable for a number ofspider species.In a Breckland context, there is little point in making a distinction between grass-heath and Callunaheath (Rothera, 1998), particularly because: These inter-grade in terms of their plant communities (Rodwell, 1991; 1992) and can occur inmosaics due to patterned soil. Historic accounts (e.g. Farrow 1915; 1917) emphasise thatheather was sporadic, dynamic and responded to the spatial distribution of rabbit grazingbeing absent in the immediate vicinity of warrens. At a number of sites, heather only re-appeared in the above ground vegetation aftermyxomatosis although it must have been represented in the soil seed bank from earlierepisodes of grazing relaxation.148