Abstract:

The relationship between the seed bank and aboveground communities has attracted much interest among plant community ecologists. The objective of this study was to address the relationships between soil seed banks and aboveground plant communities by comparing the species composition in the dry-hot valley of the Yuanjiang River. Typical shrub-grass communities in the dry-hot valley were selected and five plots were established in upper, middle, and lower sections of the Yuanjiang River watershed. A total of 100 sampling quadrats were collected, and plant communities were surveyed. In addition, soil samples were collected in three layers (0-5 cm, 5-10 cm, and 10-15 cm) in each community sample. The seed banks from the soil samples were germinated in the lab and species were identified. The results showed that (1) 76 plant species belonging to 25 families and 64 genera were found in the aboveground plant communities. These species mainly belonged to Fabaceae, Poaceae, Asteraece and Euphorbiaceae. (2) 33 plant species belonging to 14 families and 32 genera were found in the soil seed banks. These species mainly belonged to xeromorphy Gramineae. (3) In three soil layers, the proportion of the surface soil seed banks was the largest, and the numbers of seeds decreased as the depth of soil increased. (4) For each plot, few common species were found between the soil seed banks and plant communities, and thus their similarity is low. In summary, there were no significant correlations between the soil seed banks and aboveground plant communities. Moreover, several invasive species can be found both in the seed banks and aboveground plant communities.

Key words: dry-hot valley, soil seed banks, above ground plant communities, species composition, similarity, Yuanjiang River