Edaphic patchiness influences grassland regeneration from the soil seed-bank in mountain grasslands of central Argentina

The soil seed-banks in the main natural vegetation patches that make up mountain grasslands on granite substrates in central Argentina were studied. The main natural vegetation types are moist swards, tall-tussock grasslands and stony grasslands. Ten compound soil samples from each community at two soil depths (0-5 and 5-10 cm) were taken. The density of soil seed-banks was highest in moist swards, intermediate in stony grasslands and lowest in tall-tussock grasslands. Low levels of similarity were found between the established vegetation and total soil seed-bank in tall-tussock grasslands and stony grasslands, but the similarity was higher in swards. In all three communities the seed-bank was most frequently transient in nature. Short-term persistent and long-term persistent seed-banks were less frequent. Regeneration from the seed-banks after disturbance is expected to differ among communities on different edaphic patches. On the basis of the density and longevity of the soil seed-banks and the similarity to the established vegetation, potential for in situ regeneration should be lower in tall-tussock grasslands, intermediate in stony grasslands and higher in moist swards.