報告書番号

U03066

タイトル（和文）

イヌワシを頂点とする生態系の解明 -－DNA解析を利用したノウサギの生息数推定法の開発－-

タイトル（英文）

Study on the ecosystem sustaining a pair of Golden Eagles-Population size estimation of Japanese hare by fecal DNA typing-

概要 （図表や脚注は「報告書全文」に掲載しております）

DNA解析による個体識別を利用してノウサギの生息数を推定するための2種類の調査を実施した。秋田駒ケ岳山麓のスギ林が優占する1km2の地域について100mメッシュに区切り，融雪期に各メッシュより糞を採取した。糞DNAから個体識別した結果，少なくとも48頭がこの調査地を利用していたことが確認された。次に，同じスギ林内に18.5haの調査地を設定し，降雪翌日に調査を行った。雪上の足跡とそれに対応する糞の解析から，調査地を出入りしたすべての個体が識別可能であり，15頭の存在が確認された。また，調査地の出入りの追跡から調査地内にあるノウサギの寝場所の数が推測でき，寝場所の数からこの調査地の生息密度は40.5頭/km2と推定された。本研究で実施した糞DNAを利用した調査法は，従来の手法よりも高い精度で生息密度を推定できるだけでなく，行動圏や環境利用などの生態調査にも有効な方法であることが示唆された。

概要 （英文）

For conservation and management of wildlife, an accurate estimation of population size is necessary. We newly developed two methods for estimating population size of Japanese hare (Lepus brachyurus) based on individual identification using fecal DNA analysis.1) Grid-sampling method A study area (1km x 1km) was set up in Cryptomeria japonica forest at the foot of Mt. Akita-komagatake in the snow-thawing period of 2002 and divided into 100 meter squares. At the center of each grid square, two fecal pellets of hare were collected on the surface of the snow. Total 200 fecal DNA samples were analyzed using 7 microsatellite DNA and mitochondrial DNA control region. Among the 128 fecal pellets which were successfully genotyped, 48 distinct genotypes were identified. This result suggests that at least 48 different individuals used this study area during the snow cover season.2) Snow track identification method A study area (18.5ha) was set up in the same field of Grid-sampling method in the snow-falling period of 2003. On the day right after a snowfall, snow track survey was performed along the perimeter of the study area. All the snow tracks crossed the perimeter were recorded, and fecal pellets corresponding to the tracks were collected. We then sampled fecal pellets randomly inside the study area. All collected fecal samples were successfully genotyped, and 15 individual hares were identified. The number of resting sites was estimated successfully in the study area by counting the tracks of individuals which went in and out the perimeter. As a result, population density was caluculated 40.5 per km2 in this study area. Our results suggest that our methods using fecal DNA analysis were effective for not only estimating population density but also analysis of home range and genetic structure of population.

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