A FUNCTIONAL-ANALYSIS OF A LIMESTONE GRASSLAND COMMUNITY

We examine the potential of standardised data, mainly collected in the laboratory, to elucidate mechanisms of species coexistence, using a s outh-facing, infertile, species-rich limestone grassland at Miller's D ale, Derbyshire, Eng land as a model system. Standardised autecologica l data for 15 of the more important Miller's Dale species were obtaine d from the Integrated Screening Programme (ISP), and their functional attributes were reviewed in the context of a larger database, broadly representative of the British flora. Ordination of adult plant attribu tes demonstrated that the Miller's Dale species are strategically rela tively uniform; most are slow-growing, evergreen and tolerant of miner al nutrient deficiency. Ordination of seed attributes revealed more va riety among the Miller's Dale species; the main axis of variation was from species with large, transient seeds (mostly grasses) to species w ith small, persistent seeds (mostly dicots). From the ordination we de rive the predictions that germination of the latter species will be mo re temporally opportunistic and more inhibited by the presence of vege tation than the former. These predictions are consistent with data col lected in experimental studies of seed persistence and germination at the site. These data suggest that spatial and temporal variation in op portunities for regeneration is an important mechanism contributing to the high species richness of dry limestone grasslands.