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首页> 外文期刊>Archiv fur Hydrobiologie >Effects of landscape and desertification on the macroinvertebrate assemblages of rivers in Andean Patagonia
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Effects of landscape and desertification on the macroinvertebrate assemblages of rivers in Andean Patagonia

机译：景观和荒漠化对安第斯巴塔哥尼亚河流大型无脊椎动物种群的影响

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Spatial patterns in macroinvertebrate assemblage structure were examined in rivers from 6 main basins in the mountains and the Patagonian plateau, Argentina. Surber samples were taken during the low water period from 36 sites and environmental variables were also assessed. Five site groups were identified using detrended correspondence analysis (DCA), one in the mountains, one in the piedmont, and three on the plateau (north, central and south). DCA axis 1 separated sites along a physical gradient of water velocity and stream order, whereas axis 2 separated sites according to geographic location, latitude and substratum size. Piedmont sites had greater species richness than the mountains, north plateau and south plateau sites. Invertebrate density was significantly greater on the north plateau and piedmont than in the mountains and south plateau, whereas diversity (H') was significantly higher in the mountains and on the piedmont. From a landscape perspective, higher categories in biogeographical classifications (phytogeography, biozones) appear to be most useful for predicting macroinvertebrate assemblages in Patagonian rivers. Amounts of benthic organic matter and the density and biomass of functional feeding groups (FFG) were also examined in a subset of 25 rivers. During base discharge, wood, leaves and total benthic organic matter decreased significantly from the mountains to the plains, but no significant relationship was found between quantity of fine particular organic matter and distance from the source. Shredder biomass decreased significantly from the headwaters downstream, and collector biomass increased. Predator biomass was relatively similar at all sites. A strong association was found between FFGs and their food resources. The EPT index and H' decreased as desertification status increased suggesting that land degradation influences macroinvertebrate assemblages. Loss of riparian cover as a consequence of overgrazing and other land use practices has negative effects on aquatic environments in Patagonia.
机译：在山脉和阿根廷巴塔哥尼亚高原的6个主要流域的河流中，研究了大型无脊椎动物组合结构的空间格局。在枯水期从36个地点采集了Surber样品，并评估了环境变量。使用去趋势对应分析（DCA）识别了五个地点组，一个在山区，一个在山麓，三个在高原（北部，中部和南部）。 DCA轴1沿水流速度和水流顺序的物理梯度分隔了位置，而轴2则根据地理位置，纬度和地下层大小分隔了位置。皮埃蒙特地区的物种丰富度高于山区，北部高原和南部高原地区。北高原和山麓的无脊椎动物密度明显高于山区和南高原，而山区和山麓的多样性（H'）则明显更高。从景观角度来看，生物地理分类中的较高类别（植物地理学，生物区）对于预测巴塔哥尼亚河中的大型无脊椎动物集合似乎最有用。在25条河流的子集中，还研究了底栖有机物的量以及功能性饲喂组（FFG）的密度和生物量。在基础排放过程中，从山脉到平原的木材，树叶和总底栖有机物显着减少，但是在细小的特定有机物的数量与到源的距离之间没有发现显着的关系。从上游源头开始，切碎机的生物量显着减少，而收集器的生物量增加。捕食者的生物量在所有地点都相对相似。发现实蝇粮与它们的粮食资源之间有很强的联系。 EPT指数和H'随荒漠化程度的增加而降低，表明土地退化影响了大型无脊椎动物种群。由于过度放牧和其他土地使用做法而造成的河岸覆盖率的丧失对巴塔哥尼亚的水生环境产生了负面影响。

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