First report of inventory and role of macroinvertebrates and fish in Cautín river (38° S, Araucania region Chile)

Abstract The Cautin river is located in the 137 years old Araucania region, Chile (38°S), and is characterized by alterations through human interference due agriculture and towns in its surrounding basin, the presence of salmonids, and by its mixed regime, originated from snow melting in summer and rains in winter. The aim of the present study was to make a review of the inventory and ecological role of the benthic inland water macroinvertebrates of the River Cautin, in order to understand their importance in the ecosystem of the river. The fauna of this river includes a fauna composed of endemic and introduced fish, which has, however, been only poorly studied until now. The literature revealed the presence of abundant populations of Diptera, Trichoptera and Ephemeroptera larval stages, and few crustaceans specifically amphipods and freshwater crabs along the river’s course. Many of these macroinvertebrates are prey for both introduced salmonids and native fishes. Similar results have been reported for other southern Argentinean and Chilean Patagonian rivers.

摘要 考廷河（Cautin River）坐落于拥有137年发展历程的智利阿劳卡尼亚地区（Araucania Region，南纬38°），其水文与生态特征主要体现为：流域周边农业与城镇活动引发的人为干扰、鲑科鱼类（salmonids）的栖息分布，以及由夏季融雪与冬季降雨共同构成的混合型水文情势。本研究旨在梳理考廷河底栖淡水大型无脊椎动物（benthic inland water macroinvertebrates）的物种名录及其生态功能，以明确其在该河流生态系统中的核心作用。该河流的水生动物类群涵盖特有物种与外来鱼类，但截至目前相关研究仍较为匮乏。现有文献显示，沿考廷河分布有大量双翅目（Diptera）、毛翅目（Trichoptera）及蜉蝣目（Ephemeroptera）的幼虫种群，同时仅存在少量甲壳动物（crustaceans），具体为端足类（amphipods）与淡水蟹。其中多数大型无脊椎动物可作为外来鲑科鱼类与本土鱼类的捕食猎物，此类结果在阿根廷南部及智利巴塔哥尼亚地区的其他河流中亦有报道。