Authors:J. Wang, L. Huang, H. Ren, Z. Sun, and Q. Guo
Soil seed banks can act as an important source in forest regeneration, and the information on the seed bank composition is vital for determining the resilience of plant communities under severe environments such as urban settings. In this study, we examined the seed bank density and functional composition, and their relationships with aboveground vegetation in three remnant evergreen broad-leaved forests, i.e., PuGang (PG), LuoGang (LG), and DaLingShan (DLS) under urbanization in Guangzhou, South China. In both years of our study (2010–2011), seed density and species richness for overall soil seed banks and each classified life forms (tree, shrub, herb and grass) significantly differed among the forests and were much higher in the PG forest. The prevailing life forms in the seed banks were herbs and grasses, and the proportion of tree species Importance Value index (IV) of the seed banks was low. We did not detect significant difference in the percentage of exotic species seeds in the seed banks among the forests. The proportion of species with animal dispersal mode was much higher in the DLS forest than in the PG and LG forests. The similarity in species composition between standing vegetation and seed banks was low with the lower value in the DLS forest than in PG and LG forest. Our findings suggest that the regeneration potential of the soil seed banks is limited for the remnant forests in urban areas. Therefore, greater proactive and enhanced conservation efforts are thus needed.
Instead of high value willow-poplar galleries and ash-oak-elm galleries stands of non-indigenous species are present at many sites of the flood plain of Danube in the Béda-Karapancsa Region of the Danube Drava National Park. According to the Act of Nature Conservation in Hungary minders of the territories are obligated to change non-indigenous tree species to natural tree species in all forest stands (e.g. monocultures), that are on protected areas. Change of forest structure has to be determined by the recent type of stand, the future stand and the site; its speed is fitted to the whole territory. The affects of water regulation works on the area must be taken in regard. It is necessary to monitor the results of the changes of forest structure by indicators of naturalness. It can be done by the method of naturalness value of forest stands (TERMERD).