Mechanisms and ecological consequences of the over-increase of lianas in forests

Abstract

Lianas are one of the components in maintaining forest diversity. The over-increase of lianas in tropical and subtropical forests, especially in secondary forests is threatening the restoration and healthy development of forests. Few domestic researches make a comprehensive evaluation on the mechanism of the over-increase of lianas and negative effects on forests. In this paper, we reviewed and summarized the related researches on mechanisms and ecological consequences of the over-increase of lianas both at home and abroad. Based on the relevant studies we hold the opinions: (1) The increase of lianas can be corelated with drought severity, elevated atmospheric CO2, increased natural disturbance (gaps) and forest fragments. Lianas possess the advantages of rapid growth, strong reproductive capacity and phenotypic plasticity, and high resource use efficiency under the altered environment. Thus, the favorable environment and inherent advantages can contribute to the increase of lianas. (2) Lianas compete with trees by means of shading stress, resource competition and mechanical loading, abrasion, and strangulation, which all may increase the mortality of trees. (3) The over-increase of lianas can negatively affect the tree growth, reproduction, and survival; at community level, lianas can alter tree community composition and decrease community diversity; at ecosystem level, lianas can ramify forest ecosystem function by decreasing carbon storage and altering carbon, nutrient, and water cycling. Therefore, we recommend that future studies should be aimed at the correlations between population dynamic changes of liana species and environmental changes, the effect of forest disturbance on the growth of lianas, responses of lianas to the environmental changes and the adaption mechanisms, comprehensive evaluation on the ecological consequences of the increase of lianas by means of long-term dynamic monitoring plots and controlling experiments. It is also essential to find appropriate management and control strategies of the over-increase of lianas so as to provide reference for forest management and forest ecological restoration.

Keywords

• liana
• disturbance
• global change
• forest health
• forest management