Impact of landscape patterns on herb-layer diversity and seed size of Schima superba in urban remnant vegetation: A case study in Guangzhou, Southern China

Abstract

In order to explore which ecological strategies the remnant vegetation is taken to adapt to urbanization, we investigated three kinds of typical remnant vegetation (grassland, plantation, and secondary forest) in 16 sample sites along the urban–rural gradient in the city of Guangzhou. In this study, we examined plant species composition, and plant diversity, and analyzed the seed of the dominant tree species Schima superba (S. superba) in the secondary forest sites. Those indicators are strongly related with ecological strategies. Eighteen landscape pattern characteristics were determined to reveal the extent of landscape fragmentation. Geographic Information System (GIS), linear regression, and Canonical Correspondence Analysis (CCA) were conducted to analyze the influence of landscape pattern characteristics on plant communities. Results showed that (1) Fragmentation of landscape patterns caused by urbanization has a negative impact on the diversity of herb-layer plants, the dominant species of grassland in the city center are mainly weeds, such as Bidens pilosa and Neyraudia reynaudiana. (2) In order to adapt to the pressure of landscape fragmentation, seeds of S. superba have developed into a larger size, with a competitive advantage over smaller ones. (3) Two different ecological strategies of plant communities adapting to urbanization: The pioneer weeds in grasslands, with high reproductive and dispersal ability, have adopted a r-selection strategy and the dominant tree species with higher survival rates, larger individuals, and longer life spans, have adopted a K-selection strategy to resist disturbance, as well as with a larger seed size to increase viability and settlement ability.