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Maintenance and declining mechanisms of endangered relict populations in moles

鼹鼠濒危残余种群的维持与衰退机制

基本信息

批准号：
07640828
负责人：
ABE Hisashi
金额：
$ 1.28万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640828/
关键词：
Moles Endangered relict population mtDNA CO1 土壌環境 COI

项目摘要

In Mogera imaizumii, there are eight relict populations which are scattered to the southern Honshu, Shikoku, and Shodoshima, those being far from the main population of this mole distributing to the northern half of Honshu. In M.tokudae, relict populations are found at Mitsuke-Tochio and at Niitsu-Gosen where are situated in the range of M.imaizumii in the Echigo Plain. The following three types of isolating mechanisms were detected for these relict populations. a) Because of less suitable soil condition of habitats, the invasion of ecologically dominant species has been blocked and then inferior species could have maintained its range in these habitats. This case has been usually found at habitats on rocky mountain areas. b) Relict populations of ecologicallyy inferior species have been often maintained in habitats which are surrounded by barrier habitats unsuitable for dominant species. In this case, however, the former habitats are also suitable for the dominant species so that this species can easily exclude inferior species in the habitats when the dominant species could break the barrier. c) Rice fields which are the main habitats of Japanese moles have been altered to habitats unsuitable for larger moles, M.tokudae, under the plan for the basal improvement of agricultural fields. After the habitat alteration, the population of M.tokudae was sudivided by the invasion of smaller M.imaizumii into small isolated patches at the peripheral areas of the main distribution of M.tokudae in the Echigo Plain. The nucleotide sequences of the cytochrome oxidase subunit 1 gene indicated that relict populations of M.imaizumii from Shikoku, Shodoshima and Chugoku districts of Honshu constituted a closely related cluster. They showed relatively large differentiation rate from the Kii population which is rather close to Toyama and Ishikawa populations in Honshu.

在莫盖拉今泉，有8个残存种群，分散在本州南部、四国和绍岛，这些种群远离主要种群分布在本州北部。在日本沼虾中，残存种群发现于三池和新津，它们位于Echigo平原的日本沼虾范围内。对于这些残留种群，检测到了以下三种类型的隔离机制。A)由于生境的土壤条件不太适宜，生态优势种的入侵被阻止，劣势物种可以在这些生境中保持其范围。这种情况通常发生在落基山区的栖息地。B)生态上处于劣势的物种的残存种群通常维持在被不适合优势物种的屏障生境包围的生境中。然而，在这种情况下，以前的生境也适合优势物种，因此当优势物种可以打破障碍时，该物种可以很容易地排除生境中的劣势物种。C)根据农地基本改良计划，作为日本鼹鼠主要栖息地的稻田已被改造为不适合较大鼹鼠的栖息地。在栖息地改变后，在Echigo平原主要分布的Tokudae的周边地区，由于较小的Imaizumii的入侵，Tokudae的种群被分割成小的孤立斑块。细胞色素氧化酶亚基1基因的核苷酸序列表明，来自本州四国、小岛和初国地区的伊始分枝杆菌残存种群构成了一个密切相关的簇。它们表现出与Kii种群较大的分化率，与本州的富山和石川种群相当接近。