Evaluation of Environmental Conservation Measures Using Meta-a Lysis: Breeding Success and Failure of Three Species of Rare Raptors Around Road Projects in Japan

27 Mar Evaluation of Environmental Conservation Measures Using Meta-a Lysis: Breeding Success and Failure of Three Species of Rare Raptors Around Road Projects in Japan

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Abstract

開発を伴う様々な事業において，しばしば猛禽類に対する環境保全措置が求められる．一方，それら保全措置の効果は，十分に検証されていない．本研究では，平成21年～24年度に全国の国直轄道路事業において実施された環境保全措置事例を網羅的に収集し，全国のオオタカ，サシバ，クマタカの計787巣の繁殖成否（雛の巣立ち有無）を基に，メタ解析による効果検証を行った．その結果，いずれの種も道路工事の有無（工事前／着工後）で繁殖成功率に統計的に有意な差はなく，着工後の繁殖成功率も事業箇所と巣の距離が近いほど低下する傾向もなかった．また保全措置は，オオタカの繁殖成功率を有意に向上させていた．したがって猛禽類に対する環境保全措置は，既に工事前と同水準まで繁殖成功率を高めており，今後は保全技術の効率化が重要だろう．

English Abstract

As part of the environmental impact assessment of public works (e.g., road, dam, rail, and power plant construction projects), raptors are often surveyed as environmental indicator species, and environmental conservation measures (ECM) for raptors are often required when construction projects are in progress. However, the effects of ECM have not been a lyzed statistically. We aggregated the cases of ECM exhaustively in tionwide road projects between 2009 and 2012, and a lyzed the effects of ECM based on 787 nesting successes/failures of three rare raptors (Northern Goshawk, Grey-faced Buzzard and Mountain Hawk-eagle) using the meta-a lysis approach. The results showed that there was no significant difference between the nesting success rates of each species before and during roadwork projects, and that there was no downward trend with decreasing distance to the roadwork zones. ECM notably increased the nesting success rate of the Goshawk. Thus, ECM succeeded in maintained the nesting success rates of three rare raptors to a level commensurate with levels prior to roadwork projects, and efficient and effective ECM should be continued in the future.