Succession of sedimentary chironomid assemblages in recent years responding to climate change in Bayinbuluk alpine wetland, Xinjiang

Abstract

The climate pattern has shifted from the warm-dry to warm-wet conditions in the arid northwestern China since 1980s. Changes in ice melting and precipitation in alpine areas caused by this climatic change can alter wetland hydrological processes, which in turn have an effect on biological habitats and ecosystem functions. Together with local instrumental data, this study investigates the effect of climate change on chironomid succession over the past 60 years using the redundancy analysis (RDA) based on sedimentary chironomid assemblages and sedimentary proxies including 210Pb dating, total organic carbon (TOC) contents and particle size, from a sediment core derived from a dish-like depression in the Bayinbuluk alpine wetland. Chironomus plumosus-type was the dominance of chironomid species before 1990s, and replaced by phytophilous including Dicrotendips nervosus-type and Paratanytarsus penicillatus-type after that years. RDA results showed that TOC contents and particle size were the most important variables influencing the chironomid succession. The two factors can explain 31 percent of chironomid variations. Climatic through altering the water balance which affects aquatic vegetation, water turbidity and soil erosion, can affect chironomid succession indirectly.