Trait-Based Approach to Plant Composition in Dumbeongs: Importance of Management

Abstract

Traditional man-made ponds in Korea, known as dumbeongs, mainly used for irrigation purposes, are emerging as important landscape elements that support biodiversity in agricultural areas. Although many dumbeongs are well-known habitats for various organisms that contribute to local diversity conservation, plant community composition of dumbeongs has not been extensively studied. In this regard, the present study aimed to examine how plant communities in dumbeongs respond to irrigation usage, adjacent land uses and major environmental factors such as water depth, open water surface and the concentration of water nutrients. Specifically, plant functional groups were built on the basis of selected traits to improve prediction of plant community composition. Data from a field survey conducted on 20 dumbeongs located in Seocheon-gun, Chungcheongnamdo, South Korea were used. Plant functional groups were classified into 6 groups by using hierarchical analysis and non-metric multidimensional scaling. Redundancy analysis was performed to test the relationships between plant compositions and explanatory variables at both the species and functional group levels. The results showed that usage of dumbeongs for irrigation prevented nutrients from accumulating and reduction of water depth. However, the water depth mainly helped determine the plant community composition in dumbeongs at both the species and plant functional group levels. In addition, plant functional groups showed greater explanatory power when predicting plant community composition in dumbeongs due to their collective response to the depth and open water surface. Therefore the approach used in this study, i.e., trait-based analysis, can provide a specific direction to biodiversity conservation through a better understanding of ecological niche of plant communities in dumbeongs rather than merely studying plant species. Although the explanatory power was low at the functional group level, the result emphasizes that management practices such as regular use for irrigation and removal of highly dominant plant species may play a crucial role in improving ecological functions of dumbeongs.