Is the growth strategy of perennial grasses linked to their persistence pathway?

摘要

It is hypothesized that the growth strategy of perennial grasses determines their persistence pathway regardless of neighbouring species. Thus, species with contrasting growth strategies (Arrhenatherum elatius L., Dactylisglomerata L. and Festuca arundinacea L.) were evaluated as both monocultures and in a three-species mixture for two years in an intensively managed environment. Plants in all four treatments were stable throughout the experimental period. Overall, A. elatius had the highest rates of mortality and tiller appearance and F. arundinacea had the lowest. A. elatius produced a large number of tillers across all seasons, but the longevity of the tillers was the lowest among the three studied species. F. arundinacea and D. glomerata had numerous cohorts of tillers that were produced only during autumn-winter, but the half-lives of their tillers were six and three times longer than that of A. elatius tillers, respectively. No differences were observed in the tillering dynamics of the three species in monoculture or in mixed swards. The results suggest that competitive perennial grasses (like A. elatius) exhibit a high turnover of tillers throughout the year and, therefore, their persistence is dependent on regular favourable tillering conditions (water and input of nutrients), while more conservative species (like F. arundinacea) demand large amounts of resources at specific times of the year to re-establish their populations.