大气CO2浓度和气温升高对麦田节肢动物群落的影响

为了预测气候变化对麦田节肢动物群落多样性的影响, 本研究在麦田开放环境中设置4种处理, 分别是高温(高于当时气温2℃和当前CO₂浓度)、高CO₂浓度(500 μL/L和当时气温)、高温+高CO₂浓度和对照(当前CO₂浓度和气温)等, 采用定期随机抽样方法调查节肢动物群落的多样性, 用经典的多样性指数对整体节肢动物群落以及不同食性节肢动物群落多样性进行分析。共采到节肢动物3纲10目42科52种。仅“高温”和“高温+高CO₂”处理显著增大节肢动物群落的均匀度, 其余处理均无显著影响。“高温+高CO₂”处理的影响随小麦生长发育期不同而略有差异, 在苗期可增大Shannon-Wiener多样性指数, 而在后期使该指数减小; “高温+高CO₂”与“高温”处理的群落多样性较为相似。对不同食性节肢动物群落的分析表明, 与对照相比, 植食性昆虫群落在“高CO₂”下丰富度显著增大; 寄生性昆虫群落的多度在“高温”下显著增大; 腐食性等节肢动物群落的多度在“高CO₂+高温”和“高温”处理下有所增大、均匀度在“高温”下略降低, 但均未达统计上的显著水平; 捕食性节肢动物群落不受影响。本研究说明, CO₂浓度和气温升高不同程度地影响麦田节肢动物群落的物种多样性, 两类因素同时升高与各自单独升高的影响不完全一致。

Effects of elevated CO2 and increased temperature on wheat field arthropod community

To project arthropod community response to climate change in wheat fields, a field survey of arthropods over the growing season was made in the plots under a factorial combination of two CO₂ (ambient and 500 μL/L) and two temperature (ambient and +2℃) treatments. The survey collected 52 species, 42 families, 10 orders, and 3 classes. Analyses of overall arthropod community showed a significant increase in evenness due to “Elevated CO₂ + Increased temperature” treatment. Elevated CO₂ and increased temperature treatments had varying impacts on species diversity parameters within the wheat growing season. The “Elevated CO₂ + Increased temperature” treatment increased the Shannon-Wiener index slightly during the early growing season, but decreased it later in the season. Species diversity was most similar between the “Elevated CO₂ + Increased temperature” and the “Increased temperature” treatment. The analysis of arthropod communities by trophic level showed that the “Elevated CO₂” increased herbivorous insect richness and the “Increased temperature” increased parasitoid abundances, compared with the control. The treatments did not affect detritivorous and predaceous arthropod communities. The results of this study suggest that elevated CO₂ and increased temperature can affect arthropod diversity in wheat fields, and the effects may vary between both elevated CO₂ and increased temperature and individual elevation of either CO₂ and temperature.