A comparison of regeneration dynamics following gap creation at two geographically contrasting heathland sites

1. Lowland Calluna-dominated heathlands are a high priority for conservatio n in Europe. As an anthropogenic subclimax community they require regular m anagement intervention to maintain their conservation interest. 2. Increasingly, Calluna is disappearing from lowland heathlands and being replaced by grasses, especially in the Netherlands and more recently in sou th-east England. While Calluna is highly competitive over much of its life cycle, its competitive ability is reduced during the regeneration phase tha t follows the death of stands or results from management activity. 3. We examined the influence of five factors on regeneration of vegetation in gaps in two broadly similar lowland dry heaths over a 3-year period. The se were: geographical location (combining a variety of environmental contra sts); dominant species (Calluna or grasses); management techniques; gap siz e; and seed source availability. 4. Site location had the greatest effect on patterns of regeneration. Regen eration on the Wirral (north-west England) was faster and more dominated by Calluna than regeneration in Breckland (south-east England), which was dom inated by other species including grasses and annual plants. Addition of Ca lluna seed at the Breckland site failed to increase Calluna cover. It was c oncluded that climatic or other environmental factors were the most probabl e cause of poor regeneration. 5. Cover of grasses in regenerating areas was greatest in Breckland, where Deschampsia was able to establish in all gaps where there was a seed source (either in the surrounding vegetation or applied as a treatment). On the W irral, Deschampsia establishment was limited, even in gaps where a seed sou rce was applied. 6. This work has implications for the conservation management of heathlands , which currently follows a standard prescription throughout the UK. It is suggested that management regimes should be tailored to suit the conditions prevailing at individual sites as regeneration dynamics may be extremely v ariable.