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

We studied the soil seed bank of Lachemilla pinnata (Ruiz & Pav.) Rothm. (Rosaceae) 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 the germinable seed bank of L. pinnat a 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. Its density 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. On those bases, moist-sward patches are expected to play a more important role than, tall-tussock grasslands or stony grasslands in the maintenance of local populations of L. pinnata.