Potential of soil seed banks for vegetation recovery following deer exclusions under different periods of chronic herbivory in a beech forest in eastern Japan

Abstract

AbstractThis study aimed to evaluate the potential for vegetation recovery from buried seed banks following exclusion of deer after different periods of chronic herbivory in a beech forest. Using the seedling emergence method, I surveyed the floor vegetation, buried seed banks and compared survey results with that of past flora. The study areas were an area within two deer exclosure fences, one established in 1997 and the other in 2003, and the area outside the fences. With regard to floor vegetation, species diversity and dominance of vulnerable (VUL) species were higher in F1997 than in F2003, and species frequency was different among the three plots. In the soil seed banks, species richness, seed density and life form composition were different among the three plots. However, when I excluded Rubus illecebrosus, which is a VUL shrub species, seed density of VUL species was not greatly different among the plots. In addition, the species composition of soil seed banks compared with that of past flora was similar among the plots. This may be because almost no VUL herb species formed the buried seed banks. In contrast, invulnerable (INV) species formed numerous seed banks. These results demonstrate that chronic deer herbivory causes a negative effect on the composition of floor vegetation through VUL herb species, and a positive effect on the seed density of soil seed banks through INV species. Conservation measures are needed while there are still plant organs remaining aboveground.