Ecological Filtering Effect of Dicranopteris Synusia under Eucalyptus Plantation in South China

Abstract

Dicranopteris is the most representative pioneer species, dominant species and key species in degraded slope land in South China. Dicranopteris could quickly form dense synusia of a single and dominant species. In contrast to the traditional view that Dicranopteris hinders forest regeneration, we found that there are a few species that could settle down in Dicranopteris synusia. We proposed a hypothesis that Dicranopteris synusia could act as an ecological filter. In this study, we transplanted 12 target species seedlings under Dicranopteris synusia with 4 treatments to explore the ecological filtering effect of Dicranopteris synusia, and analyzed the mechanism with soil characteristics. The 4 treatments included the understory removal treatment (UR), the aboveground of Dicranopteris synusia were kept (AF), the root blanket of Dicranopteris synusia were kept (AR) and all of the Dicranopteris were kept (CK). The results showed that: 1) Compared with the red soil under Dicranopteris synusia of Eucalyptus plantation and bare ground, the contents of soil organic matter, total nitrogen, hydrolyzed nitrogen, available phosphorus, available potassium, and exchangeable base ions in the root blanket of Dicranopteris synusia were significantly higher. 2) The majority of the tree species and all of the herbaceous species could not survive with the root blanket of Dicranopteris synusia kept (AR and CK). The species that could survive with the root blanket of Dicranopteris synusia kept were Schima superba, Rhodomyrtus tomentosa, Ilex asprella and Melastoma candidum. The results indicated that Dicranopteris synusia could act as an ecological filter. The key lies in the role of root blanket of Dicranopteris synusia, and not in the improvement of soil nutrients. Theoretically, Dicranopteris synusia, especially the root blanket of Dicranopteris synusia, is closely related to the breakthrough of biological threshold for ecological restoration. In the future, it is necessary to further analyze the structure and function of the root blanket of Dicranopteris synusia. In terms of application, there are a large number of plantation types (such as Eucalyptus plantation) that Dicranopteris occupied as a single dominant understory species in South China. Therefore, we should pay more attention to the ecological filtering effect of Dicranopteris synusia in structural optimization and stand transformation. This study could provide a reference for the restoration and reconstruction of degraded slope land in South China.

Keywords

• seedling growth
• understory vegetation
• fern
• transplant seedlings
• community succession
• root blanket synusia