Leaf functional traits in Brachypodiumpinnatum (L.) Beauv., Bromus erectus Hudson and Dactylis glomerata L. as indicators of resource availability in grassland communities

摘要

Brachypodium pinnatum, Bromus erectus and Dactylis glomerata are very common species in European semi-natural grasslands but have different life strategies: B. pinnatum and B. erectus, unlike D. glomerata, are stress-tolerant competitors of xeric, resource-poor habitats. The study was made in spring and autumn of 2006, at two grassland areas (Regional Park of Monte Sole, Emilian Apennines) having similar climate conditions, but different resource availability. At each area Specific Leaf Area (SLA), Leaf Dry Matter Content (LDMC), Leaf Nitrogen Concentration (LNC) and Leaf Lignin Content (LLC) were measured in the three species. Variability of these functional traits was tested, by studying species, spatial and temporal variations, in order to investigate their value as indicators of different environmental conditions. The variations of LNC between seasons, and of SLA, LDMC and LLC between species, was highly significant. Different responses to environmental conditions in the species were confirmedby ranking of plant trait values. D. glomerata was characterized by the highest SLA and lowest LDMC and LLS values, fitting the expectations of fast-growing species. B. pinnatum and B. erectus, with lower SLA and higher LDMC and LLS values, tend towardsthe behaviour of slow-growing species. SLA and LDMC were found to be the major traits characterizing inter-site differences.