JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. British Ecological Society is collaborating with JSTOR to digitize, preserve and extend access to Journal of Applied Ecology. Summary 1. Lowland heaths are high-profile ecosystems for conservation action in England, but they are under threat from invasion by Betula spp., Pinus sylvestris, Pteridium aquilinum, Rhododendron ponticum and Ulex europaeus. 2. Ten heathland sites in the Poole Basin area of Dorset, where succession to one or other of the above species had occurred, were studied to examine the changes in vegetation and soil chemical properties. 3. A series of hypotheses to explain (i) vegetation successional trajectories, and (ii) soil chemical properties associated with vegetation change were tested using multivariate models (DECORANA -vegetation; CANOCOvegetation and soil). 4. A range of pathways was found along which heathland communities move during succession, with some successional pathways remaining closer to heathland than others. 5. The Betula spp. succession caused the greatest changes in terms of the vegetation present. The Ulex europaeus and Pinus sylvestris trajectories retained some typical heathland species. 6. Different soil nutrients were found to increase along different successional pathways, which were associated with the different successional species invading. 7. Pinus sylvestris had similar soil nutrient concentrations to those of the heathland. Sodium concentrations increased during the Rhododendron ponticum succession. Concentrations of ammonium-nitrogen and nitrate/nitrite-nitrogen increased during the Pteridium aquilinum and Ulex europaeus succession. The Betula spp. had the greatest effect on the soil nutrients with increased pH, extractable phosphorus and exchangeable calcium. 8. The results are discussed in relation to practical heathland management and the restoration of heathland after succession. Specifically, it is more sensible and costeffective to restore heathland on sites where Pinus sylvestris successions have occurred, than where Betula spp. successions have occurred.

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Summary 0 Many areas of lowland heaths are being lost due to invasion by Betula spp[\ Pinus sylvestris\ Pteridium aquilinum\ Rhododendron ponticum and Ulex europaeus[ One of the factors in~uencing the success of restoration of heathland on such sites will be the content of their viable seedbanks[ 1 Ten heathland areas in the Poole Basin area of Dorset\ where succession to one or more of the above species had occurred were studied[ The viable seedbanks of the successional sites were compared with those of nearby heathland using Canonical Discriminant Analysis[ 2 The seedbanks of all the successional stages were signi_cantly di}erent from the seedbank of the heath[ 3 The seedbanks from the Pinus sylvestris and Pteridium aquilinum successional stages contained signi_cantly lower numbers of heathland species than did the heathland seedbank\ although few non heathland species were present[ 4 The seedbanks from the Betula spp[\ Rhododendron ponticum and Ulex europaeus successional sites contained both signi_cantly lower numbers of heathland species and signi_cantly higher numbers of non heathland species than the heathland seedbank[ 5 The results are discussed in relation to the restoration of heathland on successional sites and the use of the seedbank as a source of propagales for the establishment of heathland species[

and xThe Royal Society for the Protection of Birds, 10 Albyn Terrace, Aberdeen AB10 1YP, UK Summary 1. Lowland heaths are high-pro®le ecosystems for conservation action in Britain, but many areas have been invaded by Betula spp., Pinus sylvestris, Pteridium aquilinum and Rhododendron ponticum. As succession occurs on heaths, changes occur in both the vegetation and the soil chemical properties of the site. 2. Nine heathland sites in the Poole Basin area of Dorset were studied, where management of successional sites to restore heathland had occurred. The ecacy of heathland restoration in terms of both the vegetation and the soil chemical properties was assessed. 3. The management had allowed many heathland species to establish and the majority of sites to start to become similar to the neighbouring heathland. The reversion of increased soil nutrients was found to be more problematic, with levels of ammonium±nitrogen, phosphorus, pH, calcium and magnesium remaining greater than those of the heathland soils. 4. The vegetation and soil data were analysed using CANOCO (canonical correspondence analysis) and were then used to test four hypothetical models that related changes in biotic factors (vegetation) and abiotic variables (soil nutrients) following management to the success of the restoration of heathland on successional sites. 5. A second CANOCO analysis was carried out in which the managed sites were treated as passive samples. This model was used to measure the distances between the heath, successional and managed sites. These distances provided measures of management success and the resilience of the treated late-successional ecosystem. 6. The successional species present before management aected the success of reversion; management of Pinus sylvestris sites was generally more successful than management of others sites, especially those invaded by Betula. The most signi®-cant eect of dierent management techniques resulted from litter-stripping, which reduced the nutrients available and improved and accelerated the success of reversion.

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