Population model of Rana japonica crossing agricultural concrete canals: evaluating population conservation by improving the migration routes of frogs
Population model of Rana japonica crossing agricultural concrete canals: evaluating population conservation by improving the migration routes of frogs
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DOI：
10.1007/s10333-012-0313-7
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发表时间：
2012-02
影响因子：
2.2
通讯作者：
Keiji Watabe;Y. Senga;A. Mori;N. Koizumi;Takeshi Takemura;K. Nishida
中科院分区：
文献类型：
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作者：
Keiji Watabe;Y. Senga;A. Mori;N. Koizumi;Takeshi Takemura;K. Nishida
在日本，随着土地整理项目的实施，在水田地区普遍安装了具有深混凝土壁的农业运河。这样的运河为青蛙的迁移创造了一个关键的障碍，因为落入其中后无法逃脱。因此，为了保护濒危的青蛙种群，已经开发了允许迁移的青蛙穿过农业运河的对策，例如盖子结构，以防止青蛙落入或创造部分斜坡以允许逃跑。本研究的目的是设计一种方法来评估濒危的日本布朗蛙，日本林蛙的种群生存力，实施的对策。研究了两种类型的模型模拟：（1）基于年龄结构模型的“基本模型”和（2）评估迁移青蛙穿越运河的“穿越模型”。参数，如存活率和繁殖力，估计从现场观察数据的年龄依赖的人口波动。一个基本的模型模拟与现场观测数据的比较表明模型的有效性。最初种群为1，000个个体的杂交模型模拟表明，大于30-40%的杂交比例将在5年后达到95%的种群生存力。模拟还表明，超过80%的杂交比例也将在40年后达到95%的种群生存力。这些结果表明，青蛙在迁移期间的生存是有保障的，只要安装后没有额外的对策是必要的。
Agricultural canals with deep concrete walls are commonly installed in paddy field areas following land consolidation projects in Japan. Such canals create a critical migration barrier for frogs, as escape is not possible after falling in. Hence, countermeasures that allow migrating frogs to cross agricultural canals, such as lid structures to prevent frogs from falling in or the creation of partial slopes to allow escape, have been developed to conserve endangered frog populations. The objective of this study was to design a method for evaluating the population viability of the endangered Japanese Brown Frog,Rana japonica, following the implementation of countermeasures. Two types of model simulations were examined: (1) a “basic model,” based on an age-structured model and (2) a “crossing model,” to evaluate migrating frogs crossing canals. Parameters, such as survival rate and fecundity, were estimated from field observation data of age-dependent population fluctuations. Comparison of a basic model simulation with the field observation data suggests model validation. The crossing model simulation, which had an initial population of 1,000 individuals, showed that a crossing proportion of greater than 30–40% would achieve 95% population viability after 5 years. The simulation also showed that a crossing proportion of over 80% would also achieve 95% population viability after 40 years. These results indicate that frog survival during the migration period is insured, as long as no additional countermeasures are necessary after installation.