Determinants of invertebrate community structure in glacial‐melt streams of southeast Tibet
Determinants of invertebrate community structure in glacial‐melt streams of southeast Tibet
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DOI：
10.1111/fwb.13716
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发表时间：
2021-04
影响因子：
2.7
通讯作者：
Heather Fair;P. Smiley;R. Lanno
中科院分区：
文献类型：
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作者：
Heather Fair;P. Smiley;R. Lanno
一个被广泛研究的冰川融水无脊椎动物群落动态预测模型描述了群落结构随水温变化的纵向变化，以及随着与冰川距离的增加而增加的通道稳定性。以前在欧洲、格陵兰岛、新西兰和南美洲进行的研究支持了无脊椎动物模型的预测，并对其进行了改进。2010年，我们在西藏东南部三江并流地区的三个亚高山冰川融水流域的14个地点采集了无脊椎动物样本，测量了水温、电导率、浊度和相关的冰川相关变量，并对这些数据进行了分析。2011年、2013年和2015年。我们的站点包括从上游的metakryal站点（夏季最高水温<2°C）到最下游的站点（夏季最高水温>10°C）的温度梯度靠近湄公河。我们评估了无脊椎动物群落结构与原位水温和通道稳定性的关系，这是无脊椎动物模型中的焦点生境变量。额外的栖息地变量的距离冰川，冰川的大小，电导率和浊度进行了评估，看看这些是更重要的决定因素的群落结构比原位水温和通道stability.Minimum和原位水温呈正相关，但Pfankuch通道稳定性指数底部得分与冰川的距离。因此，在我们的研究区域内的物理模板不同的无脊椎动物model.Similarly的预期模板，原位水温本身或结合Pfankuch指数最好的解释五个无脊椎动物的响应变量。与无脊椎动物模型相反，电导率和浊度最好地解释了无脊椎动物类群的丰富度，密度，和网站的第一和第二个去趋势对应分析轴的相对丰度的分数。然而，在我们的后寒武纪站点，我们经常捕获到13个分类群（2个Nemouridae形态型，Diamesinae，Orthocladiinae，Rhyacophila，Epeorus，Taenioprodidae，Baetis，Capnia，Simuliidae，Limnephilidae，Himalopsyche和Collembola）。我们的研究结果强调了开发适用于亚洲冰川融水流的无脊椎动物模型的区域版本的必要性，这些冰川融水流在其整个集水区具有不稳定的河道，并且在冬季不会冻结。
A widely examined predictive model of invertebrate community dynamics in glacial‐melt streams describes longitudinal changes in community structure with changing water temperature and channel stability with increasing distance from glaciers. Previous studies conducted in Europe, Greenland, New Zealand, and South America have supported the predictions of the invertebrate model and contributed to its refinement. However, none has evaluated if the model fits invertebrate community dynamics over a full range of distances from the glacier and water temperature conditions within glacial‐melt streams in southeast Tibet.We sampled invertebrates and measured water temperature, specific conductivity, turbidity, and associated glacier‐related variables within 14 sites in three subalpine glacial‐melt catchments in southeastern Tibet's Three Parallel Rivers region during 2010, 2011, 2013, and 2015. Our sites encompassed a temperature gradient from the upstream metakryal sites (maximum summer water temperature <2°C) to the furthest downstream site (maximum summer temperature >10°C) near the Mekong River.We evaluated the relationships of invertebrate community structure with in situ water temperature and channel stability which are the focal habitat variables in the invertebrate model. The additional habitat variables of distance from the glacier, glacier size, conductivity, and turbidity were evaluated to see if these were more important determinants of community structure than in situ water temperature and channel stability.Minimum and in situ water temperatures were positively correlated with distance from the glacier but Pfankuch Channel Stability Index bottom scores were not. Thus, the physical template within our study area differed from the expected template of the invertebrate model.Similar to the invertebrate model, in situ water temperature by itself or combined with Pfankuch index best explained five invertebrate response variables. In contrast with the invertebrate model, conductivity and turbidity best explained invertebrate taxa richness, density, and the site scores of the first and second detrended correspondence analysis axes of relative abundance.The invertebrate model predicts that only Diamesinae will occur in metakryal sites. However, in our metakryal sites we frequently captured 13 taxa (two Nemouridae morphotypes, Diamesinae, Orthocladiinae,Rhyacophila,Epeorus, Taeniopterygidae,Baetis,Capnia, Simuliidae, Limnephilidae,Himalopsyche, and Collembola).Invertebrate‐habitat relationships and taxa occurrence trends in glacial‐melt catchments in southeast Tibet differed from the invertebrate model predictions. Our findings highlight the need to develop a regional version of the invertebrate model applicable to Asian glacial‐melt streams with unstable stream channels throughout their catchments and that do not freeze in the winter.