Basic characteristics and influencing factors of seed rain of woody plant in fragmented habitats in the Thousand Island Lake

Abstract

Seed rain can affect species composition, forest community diversity, and plant population and community renewal. Studying the characteristics of seed rain is of great significance for in-depth research on regeneration strategies and restoration of plant population. In order to explore the basic characteristics of seed rain in fragmented habitats, this study used monthly seed rain data collected from 2015 to 2020, and used the Kruskal-Wallis test to analyze the annual difference of the seed rain density of woody plant, and to analyze the monthly difference of the seed rain density of species with different dispersal syndromes. Then we used linear mixed-effect models to test the relationships among island spatial attributes (i. e., island area, the distance to the mainland, and the distance to the nearest island), climatic factors (i. e., accumulated temperature above 0 degrees, precipitation) and seed rain density of woody plant and species with different dispersal syndromes. The results were as follows: (1) During the six years of 2015-2020, a total of 877 178 mature seeds of woody plant were collected from 240 seed traps in 29 study islands, belonging to 26 families, 40 genera and 52 species. (2) Zoochory was the major dispersal syndrome in the Thousand Island Lake, there were great differences in the temporal dynamics of seed rain in different dispersal syndromes. (3) The annual density of seed rain of woody plant was significantly positively correlated with island area and annual accumulated temperature, and significantly negatively correlated with annual precipitation. (4) The monthly density of seed rain of autochory was significantly positively correlated with the distance to the nearest island, while that of zoochory was significantly positively correlated with the distance to the mainland, and that of anemochory was significantly positively correlated with the monthly accumulated temperature. In conclusion, habitat fragmentation affect the temporal dynamics of the seed rain of woody plant through island spatial attributes.

Keywords

• seed rain
• dispersal syndrome
• habitat fragmentation
• temporal dynamic
• woody plant