Habitat Preferences and Trophic Position of Brachydiplax chalybea flavovittata Ris, 1911 (Insecta: Odonata) Larvae in Youngsan River Wetlands of South Korea.

Jong-Yun Choi,Seong-Ki Kim,Jeong-Cheol Kim,Soon-Jik Kwon

doi:10.3390/insects11050273

Abstract

In freshwater ecosystems, habitat heterogeneity supports high invertebrate density and diversity, and it contributes to the introduction and settlement of non-native species. In the present study, we identified the habitat preferences and trophic level of Brachydiplax chalybea flavovittata larvae, which were distributed in four of the 17 wetlands we examined in the Yeongsan River basin, South Korea. Larval density varied across four microhabitat types: open water area, and microhabitats dominated by Myriophyllum aquaticum, Paspalum distichum, and Zizania latifolia. Microhabitats dominated by M. aquaticum had the highest larval density, followed by those dominated by P. distichum. The larvae were more prevalent in silt sediments than in plant debris or sand. Stable isotope analysis showed that B. chalybea flavovittata is likely to consume, as a food source, other species of Odonata larvae. We conclude that successful settlement of B. chalybea flavovittata can be attributed to their habitat preferences. As temperature increases due to climate change, the likelihood of B. chalybea flavovittata spreading throughout South Korea increases. We, therefore, recommend continued monitoring of the spread and ecological impacts of B. chalybea flavovittata.

Highlights

Invertebrate communities play an important role in the functioning of freshwater wetland ecosystems
We identified four different microhabitat types based on the heterogeneity of the macrophytic composition in each wetland: (1) open water area, (2) area covered by Myriophyllum aquaticum, (3) area covered by Paspalum distichum, and (4) area covered by Zizania latifolia
Our results showed little relationship between the density of Odonata larvae and the biomass of aquatic macrophytes, we observed that the larvae preferred areas that were moderately covered by aquatic macrophytes than open water area not covered by aquatic macrophytes

Summary

Introduction

Invertebrate communities play an important role in the functioning of freshwater wetland ecosystems. Aquatic invertebrates occupy an intermediate level in the freshwater food web, between phyto- and zooplankton and fish, and they are crucial for regulating food web dynamics [1]. Because spatiotemporal distribution patterns of invertebrates directly influence the population growth and fecundity of other major components of wetland food webs, these organisms have a strong impact on ecosystem health. Given their intermediate trophic position, the aquatic invertebrates require habitat conditions that supply sufficient food resources, and provide refuge from predators. Areas populated by emergent macrophytes, such as Phragmites communis Trin. and Typha orientalis

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Discussion

Conclusion