STUDIES OF THE FEASIBILITY OF RECREATING CHALK GRASSLAND VEGETATION ON EX-ARABLE LAND .2. GERMINATION AND EARLY SURVIVORSHIP OF SEEDLINGS UNDER DIFFERENT MANAGEMENT REGIMES

1. Germination and establishment of the chalk grassland perennials Pim pinella saxifraga, Scabiosa columbaria, Plantago media and Achillea mi llefolium were compared in undisturbed chalk grassland, and in ex-arab le land where the vegetation was either uncut. cut and maintained at a height of 3 cm, or completely cleared. 2. Virtually no germination wa s recorded for all four species in uncut quadrats on ex-arable land. G ermination of Achillea and Plantago was highest in cleared ex-arable a nd that of Pimpinella highest in cut ex-arable. The ratio of germinati on in cleared and cut ex-arable increased as size of seed decreased be tween the species. Germination of the largest-seeded species. Pimpinel la, was not significantly different in cut exarable and in laboratory conditions. 3. Differences in seedling survival were sought between th e vegetation types, using concurrently recruited cohorts of seedlings of each species. The significant results were consistent for all speci es: overall seedling survival was highest in cut ex-arable. intermedia te in cleared ex-arable and lowest in chalk grassland. Analysis of res iduals revealed that the greatest differences in proportional survivor ship between treatments occurred during the first 2 weeks of cohort li fe, regardless of the date of cohort recruitment, suggesting that vege tation type is a more potent determinant of mortality risk than climat ic conditions during this early period of growth, Comparisons of resid uals also demonstrated that survivorship decreased from cut ex-arable to cleared ex-arable to chalk grassland. Sites where vegetation is sho rt may be more favourable for seedling establishment than uncut sites because of lower competition, and better than cleared sites because th e short vegetation cover moderates temperature Fluctuations and retain s more soil moisture. 4. It is concluded from this and related studies , that sowing suitable species, and implementing a management regime w hich reduces. but does not remove all vegetation cover. will maximize the chances of establishing chalk grassland species on ex-arable sites . Management prescriptions which include mowing and razing on ex-arabl e land will make the best use of the environmental opportunities, pres ented by agricultural extensification, to restore ecologically valuabl e communities.