Conservation of freshwater and blackish water benthic invertebrates endemic to the Bonin Islands

2005-2007年，在日本小笠原（小笠原）群岛5个岛屿的50多个地点对淡水和微咸水大型无脊椎动物进行了定量和定性采样。结果，在这些岛屿的河流中新发现了隶属于3个节肢动物目的4种特有物种和1种外来物种。首先，根据Chichi-jima和Haha-jima的源头地区采集的标本，描述了一种新的无鳞虾属。其次，从秩岛的溪流中描述了一种新的鹅属。第三，在哈哈哈岛的溪流中发现了一种新的扁平类等足动物——Gnorimosphaeroma。最后，在哈哈哈岛的一个储层中还发现了另一种新的等足类动物。在调查过程中，首次在赤岛县的溪流中发现了一种引种的野螺。还对岛屿特有的摇尾虫进行了调查，以评估其脆弱性。根据在不同生境采集的幼虫，确定了克氏螯螯鼠、气腹腹鼠、气腹腹鼠和气腹腹鼠的生境。在花岛水库岸边采集了tokunagi型弯尾鱼的幼虫。这是海洋岛屿上首次记录到的雕腱动物。至于球蝇，虽然在哈哈哈岛采集到一株幼小的嗜Rhyacophila幼虫，但其分类地位和起源仍不确定。另一方面，特有种Goera ogasawaraensis的幼虫密度较以往有所下降。与研究结果相比，两种甲壳类特有种的种群规模呈下降趋势。根据红色名录标准，这三个物种被日本环境省列为濒危和受威胁物种。

The quantitative and qualitative sampling on the freshwater and brackish water macro-invertebrates were conducted at more than 50 sites covering five islands belonging to the Ogasawara (Bonin) Islands, Japan during 2005-2007. As a result, four endemic species belonging to three arthropod orders and an alien thiarid species were newly found in the streams of these islands. At first, a new atyid shrimp of the genus Paratya is described based on the specimens collected from the head-water regions of Chichi-jima and Haha-jima. Secondary, a new caddisfy of the genus Goera is described from the streams of Chichi-jima. Third, a new flabelliferan isopod of the genus Gnorimosphaeroma is described from the streams of Haha-jima. And last, another new isopod of the genus Spherillo is also described from a reservoir of Haha-jima. During the course of this survey, an introduced thiarid snail of the genus Malanoides recorded from the streams of Chichi-jima for the first time.The surveys on the endemic chironomids were also conducted in the islands to assess their vulnerability. The habitats of Chironomus claggi, Cricoropus ogasaseptimus, Macropelopia ogasaseztdecima ant Tanytarsus ogasaquartus were confirmed based on larval collection from varous habitats. The larvae of Glyptotendipes tokunagai were collected at the shore of a reservoir in Hana-jima Island. This is the first record of Glyptotendipes from the oceanic islands.As for the caddisflies, even though an immature Rhyacophila larva was collected from Haha-jima, its taxonomic status and origin is still uncertain. On the other hand, the endemic species Goera ogasawaraensis showed a decline in its larval densities, compared with previous study. In relation to the two crustacean endemic species, declinations in population's size are observed, compared with study. Based on red list criteria, these three species were listed as endangered and threatened species by the Ministry of Environment, Japan.