A functional analysis of a limestone grassland community


Corresponding author; Tel. +44 114 2824314; Fax +44 114 2760159; E-mail ken.thompson@sheffield.ac.uk


Abstract. We examine the potential of standardised data, mainly collected in the laboratory, to elucidate mechanisms of species coexistence, using a south-facing, infertile, species- rich limestone grassland at Miller's Dale, Derbyshire, England as a model system. Standardised autecological data for 15 of the more important Miller's Dale species were obtained 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 attributes demonstrated that the Miller's Dale species are strategically relatively uniform; most are slow-growing, evergreen and tolerant of mineral nutrient deficiency. Ordination of seed attributes revealed more variety among the Miller's Dale species; the main axis of variation was from species with large, transient seeds (mostly grasses) to species with small, persistent seeds (mostly dicots). From the ordination we derive the predictions that germination of the latter species will be more temporally opportunistic and more inhibited by the presence of vegetation than the former. These predictions are consistent with data collected in experimental studies of seed persistence and germination at the site. These data suggest that spatial and temporal variation in opportunities for regeneration is an important mechanism contributing to the high species richness of dry limestone grasslands.