Seed banks in pastures: Special reference to a persistent soil seed bank of invading species Carex albata Boott
2001
Watanabe, N. (Tohoku Univ., Sendai (Japan)) | Nishiwaki, A. | Sugawara, K.
Carex albata Boott is a weed that invades sown pastures and dominates by seed reproduction. To examine the traits of a C. albata soil seed bank, we collected soil samples from several grasslands prior to the seed dispersal and investigated the density of buried seeds by the seedling emergence method. C. albata buried seeds were found in all of the grasslands researched. It became clear that C. albata forms a persistent soil seed bank. The germinative soil seed density of C. albata increased with increase in the coverage above ground level. Particularly, in sown pastures, which have high C. albata coverage, the germinative soil seed density was high; 78,580 seeds/square m. C. albata seeds have no special apparatus for dispersal, and they seem to accumulate predominantly in the soil of C. albata-dominant pastures. On the other hand, in grasslands, where C. albata hardly appeared above ground level, C. albata seeds were found in the soil. Their accumulation may have been caused by animal-assisted dispersal. In sown pastures, bare ground frequently occurs as a result of trampling and treading by grazing animals or by farm vehicles used in grassland management. Thus, C. albata, which forms a persistent soil seed bank over a wide area of a pasture, appears to have the advantages of invasion and domination of sown pastures.
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