Extinction risks and cofactors of amphibia

生物多样性的保护取决于规划过程的规模。首先，利用简单的生境模型在国家或区域尺度上广泛筛选优先区域。第二步是在景观尺度上设计保护区。我们在这两个尺度上建立了两栖动物栖息地模型，并讨论了模型在保护中的实用性。在全国范围内的风险评估和系统地理研究，云蝾螈的存在和不存在的数据，在滋贺和大阪府。采用Logistic模型估计了这两个物种的潜在栖息地。利用生态位因子分析对仅有存在数据的物种的生境适宜性进行了估计。通过将土地利用规划图与潜在栖息地图叠加，对这些动物的未来风险进行了评估。为了确定nebulosus的区域种群单位，在线粒体DNA控制区对420个碱基对进行了测序。结果显示了大量的系统地理结构和强烈的种群水平分离。本种共检出4个类群。利用生态调查结果、1/2,500植被图和10 m DEM，建立了景观尺度（1 km x 2 km范围）的云鲵生境模型。利用该模型估算了几种土地变化情景下蝾螈的灭绝风险。超人口风险评估允许对复杂景观（如日本中山）的环境影响进行复杂的评估。小水坝对日本大鲵繁殖季节前上游迁移的影响。但可以预见的是，小型水坝会阻止水流的移动。我们调查了。研究了日本西部木子河水系初卡河中小水坝对秋卡河洄游的影响。我们调查了1523米的河段，包括6个水坝，并标记了104个人。每座水坝上都有10多只企鹅向上游移动。但事实上，在高度超过30厘米、倾斜度超过30°的水坝下观察到的许多个体表明，如果没有旁路或立足点，日本稻虱是无法越过这些水坝的。捕食者化学线索介导的雾状海蛾回避反应。研究了云蝾螈（h.n nebulosus）幼虫的反捕食行为。在实验中，我们测试了捕食性蝾螈和小龙虾的作用，蝌蚪的非致死作用和经验不足的鱼的作用。我们发现，H.nebulosus识别捕食者不是基于视觉线索，而是基于捕食者发出的kairomonas。未在临时池中生活的掠食性鱼鲫鱼的幼虫对凯罗蒙激素无应答，表明对非同一生境的掠食性鱼不存在回避反应。少

Conservation of biodiversity is the scale dependent in the planning process. At first, priority areas are screened extensively on the national or regional scale by using a simple habitat model. The second step is to design a conservation area in the landscape scale. We developed habitat models for amphibias in this two scales and discussed usefulness of the models in conservation1.Risk assessment in national scale and phylogeographic studyPresence and absence data were available for the clouded salamander and in Shiga and Osaka Prefecture. Logistic models were used to estimate the potential habitat for these two species. Habitat suitability was estimated using Ecological-Niche Factor Analysis for species in which only presence data are available. Future risks were evaluated for these animals by overlaying land use planning maps with the potential habitat maps. To identify regional population units of H.nebulosus, 420 base pairs were sequenced within the mitochondrial DNA control region … More . Results indicate substantial phylogeographic structuring and strong population-level separations. Four groups were detected among this species.2.Risk assessment in landscape scaleA habitat model in landscape scale (1 km x 2 km range) was built for the clouded salamander by using a result of ecological survey and a 1/2,500 vegetation map and 10 m DEM. This model was used to estimate extinction risk of the salamander in several scenarios of land change. The risk assessment of metapopulation allows a sophisticate evaluation of environmental impacts in complex landscapes such as Satoyama in Japan.3.Influence of small dams on the movements of Japanese giant salamander.A.japonicus move to up stream before their breeding season. But it is predictable that the movement is prevented by small dams. We surveyed. a seasonal movement of A.japonicus and examined the effect of small dams on the movement in Hatuka river of Muko river system in western Japan. We surveyed in 1523 m section of the river that include six dams, and marked 104 individuals. More than 10 individuals moved up stream over each of the dams. But the fact that many individuals were observed just under dams that are taller than 30 cm and 30° in the inclination suggests that A.japonicus cannot pass over those dams without a bypass or a foothold4.Avoidance responses of (Hynobius nebulosus mediated by predator chemical cue.We studied antipredator behavior of the clouded salamander (H.nebulosus)larvae. In our experiment, we tested the effects of predatory newt and crayfish, non-lethal effects of tadpole and effects of inexperience fish We found that H.nebulosus can recognize predators not based on visual cue but kairomones emitted by the predator. larvae did not respond to kairomones of predatory fish Carassius auratus which did not inhabit in temporary pool, therefore it suggested that H.nebulosus do not have avoidance response to predator not inhabit the same habitat. Less