大型底栖无脊椎动物对溪流中三角枫落叶分解的影响

采用复合网袋法，研究了冬季南京紫金山三角枫落叶在无干扰溪流和生态恢复溪流中的分解过程.结果表明：112 d后，三角枫落叶无灰干质量剩余率为31％～62％，分解速率符合指数衰减模型(P<0.05).在生态恢复溪流和无干扰溪流的流水生境中, 三角枫落叶的分解速率分别为0.0030 d^-1和0.0064 d^-1，静水生境中分别为0.0018 d^-1和0.0016 d^-1.流水生境中，无干扰溪流网袋内的大型底栖动物多度和生物量显著高于恢复溪流(P<0.05)，而静水中无显著差异(P>0.05).无干扰溪流中的撕食者多度比例最高(70.4%)，以栉水虱为主；生态恢复溪流中滤食者的多度比例最高(37.8%),以长跗摇蚊属为主.流水生境中三角枫落叶的分解速率与撕食者物种丰富度和多度相关性显著(P<0.01)，而与生物量的相关性不显著(P>0.05).说明冬季溪流中撕食者的物种丰富度和多度决定三角枫落叶的分解速率.

Effects of benthic macro-invertebrate on decomposition of Acer buergerianum leaf litter in streams.

By using composite mesh bag method, the effects of benthic macro-invertebrate in an undisturbed stream and an ecologically restored stream on the decomposition process of Acer buergerianum leaf litter from the Purple Mountain of Nanjing in winter were studied. After 112 days of decomposition, the remaining rate of A. buergerianum leaf litter based on ash-free dry mass was 31〖KG-*2〗- 〖KG-*7〗62%, and the decomposition rate followed a declined exponential equation (P<005). In the flowing water of the undisturbed and ecologically restored streams, the decomposition rate of leaf litter was 00064 d-1 and 00030 d-1; while in the still water of the streams, it was 00016 d-1 and 00018 d-1, respectively. The abundance and biomass of benthic macro-invertebrate were significantly higher in the flowing water of undisturbed stream than in that of ecologically restored stream (P<005), but had no significant differences in the still water of the two streams. Shredders (mainly Asellus sp.) had the highest abundance (704%) in the flowing water of undisturbed stream, while filterers (mainly Tanytarsus sp.) were dominant (378%) in the flowing water of ecologically restored stream. The decomposition rate of the leaf litter was significantly correlated with the richness and abundance of shredder species in flowing water (P<001), but had less correlation with the biomass of the shredders, suggesting that the decomposition of A. buergerianum leaf litter in streams in winter was more dependent on the richness and abundance of shredders.