Scholarlink

<p>Concrete channels laid around rice paddies have smooth and steep walls, making it impossible for frogs that fall into these channels to escape. This poses an obstacle to their migration between ecosystems. Polyethylene net escape devices (escape nets) have been proposed as a countermeasure. This study evaluated the performance of escape nets by comparing their effectiveness on four species with a distribution range in the same area: <i>Pelophylax porosus brevipodus</i>, <i>Fejervarya kawamurai</i>, <i>Pelophylax nigromaculata</i>, and&#xa0;<i>Glandirana rugosa</i>. The escape rates of adults (previous years’ metamorphs) of the four species and subadults (newly metamorphosed individuals) of <i>P. nigromaculatus</i> increased significantly when escape nets were placed at angles of 80° or 90° to the ground in an indoor experimental setup enclosed by concrete vertical walls. In contrast, the escape rates were lower for the subadults of <i>P. porosus brevipodus</i> and <i>F. kawamurai</i> than for the adults. For adult <i>P. porosus brevipodus</i>, which is considered to have a low escape capability, the time required to escape was halved when the escape net was installed. However, the effectiveness of the escape net decreased when it was installed at a 90° angle. Based on these results, we propose the following for the field application of escape nets: (i) although the performance of escape nets is relatively high, fall prevention measures should also be considered for the subadults of the two species, and (ii) a gradual slope, rather than a vertical one, is preferable for more effective escapes by adult <i>P. porosus brevipodus</i>.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Performance evaluation of escape nets for frogs falling into agricultural channels and comparison of escape capabilities of four frog species

  • 期刊论文

  • 发表日期：

    2025年6月11日

查看全文
  • Yuuichi Tanaka,
  • Hidenori Horikawa,
  • Akiko Saeki

摘要

Concrete channels laid around rice paddies have smooth and steep walls, making it impossible for frogs that fall into these channels to escape. This poses an obstacle to their migration between ecosystems. Polyethylene net escape devices (escape nets) have been proposed as a countermeasure. This study evaluated the performance of escape nets by comparing their effectiveness on four species with a distribution range in the same area: Pelophylax porosus brevipodus, Fejervarya kawamurai, Pelophylax nigromaculata, and Glandirana rugosa. The escape rates of adults (previous years’ metamorphs) of the four species and subadults (newly metamorphosed individuals) of P. nigromaculatus increased significantly when escape nets were placed at angles of 80° or 90° to the ground in an indoor experimental setup enclosed by concrete vertical walls. In contrast, the escape rates were lower for the subadults of P. porosus brevipodus and F. kawamurai than for the adults. For adult P. porosus brevipodus, which is considered to have a low escape capability, the time required to escape was halved when the escape net was installed. However, the effectiveness of the escape net decreased when it was installed at a 90° angle. Based on these results, we propose the following for the field application of escape nets: (i) although the performance of escape nets is relatively high, fall prevention measures should also be considered for the subadults of the two species, and (ii) a gradual slope, rather than a vertical one, is preferable for more effective escapes by adult P. porosus brevipodus.