Seed bank dynamics of Lachemilla pinnata (Rosaceae) in different plant communities of mountain grasslands in central Argentina

摘要

Lachemilla pinnata (Rosaceae) is a common montane species in South America which is highly selected by domestic and native grazers and possesses high forage quality. Its seed bank dynamics were investigated in the main vegetation patches that make up mountain grasslands on granitic substrate in central Argentina: moist swards, tall-tussock grasslands and stony grasslands. Ten compound soil samples from each community at two soil depths (0-5 cm and 5-10 cm) were taken. In general, the density of thegerminable seed bank of L. pinnata was larger in autumn after the seed rain, increased with its relative cover in the established vegetation, and sharply decreased with soil depth. The seed bank of L. pinnata was classified as short-term persistent. Itsdensity was higher in moist swards, where it was abundant and could produce flowers and fruits, than in stony grasslands where its cover was very low, or tall-tussock grasslands, where no flowering events were recorded. It is suggested that moist-swardpatches will play a more important role than tall-tussock grasslands or stony grasslands in the maintenance of local populations of L. pinnata.