Fundamental Experiments to Develop Eco-Friendly Techniques for Conserving Frog Habitat in Paddy Areas: Escape Countermeasures for Frogs Falling into Agricultural Concrete Canals:Escape Countermeasures for Frogs Falling into Agricultural Concrete Canals

JARQ : Japan Agricultural Research Quarterly
ISSN 00213551
書誌レコードID(総合目録DB) AA0068709X
44-04-10.pdf1.33 MB

Frogs often drown in agricultural canals with deep concrete walls that are installed commonly in paddy areas after land consolidation projects in Japan because they cannot escape after falling into the canal. We propose a partial concrete canal with gently sloped walls as a countermeasure for frogs to escape the canal and investigated the preferable angle of the sloped walls, water depth and flow velocity for Rana porosa porosa. Our experiments showed that only 13 individuals (2%) escaped by leaping out of the canal, indicating that climbing up is the main escape behavior of R. p. porosa. Walls with slopes of 30-45 degrees allowed 50-60% of frogs to escape from experimental canals, the frogs especially easily climbed up walls with a 30 degree slope. Adjusting water depth to 5 cm or more would assist the frogs in reaching the escape countermeasures because at such depths frogs are not able to stand on the canal bottom and to move freely about. Flow velocity should be slower around the countermeasures because R. p. porosa is not good at long-distance swimming and cannot remain under running water for a long time. The broadened inlets of this new canal design provide water of slower velocity near the shores of the sloped walls, which encourages frogs to escape.

作成者 WATABE Keiji MORI Atsushi KOIZUMI Noriyuki TAKEMURA Takeshi

climbing capability

ecosystem conservation


Rana porosa porosa

Tokyo Daruma Pond Frog

公開者 Japan International Research Center for Agricultural Sciences
国立情報学研究所メタデータ主題語彙集(資源タイプ) Journal Article
開始ページ 405
終了ページ 413
DOI 10.6090/jarq.44.405
権利 Japan International Research Center for Agricultural Sciences
言語 eng