Temporal Changes of land covers analyzed by satellite remote sensing and habitat states of the Iriomote cat Prionailurus iriomotensis
Temporal Changes of land covers analyzed by satellite remote sensing and habitat states of the Iriomote cat Prionailurus iriomotensis
复制标题
卫星遥感分析土地覆盖随时间变化及西表猫 Prionailurus iriomotensis 栖息地状态
DOI：
10.5738/jale.7.25
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Izawa
中科院分区：
文献类型：
--
作者：
Shinichi Watanabe;Nozomi Nakanishi;N. Sakaguchi;T. Doi;M. Izawa
西表猫 Prionailurus iriomotensis 是一种小型猫科动物，仅发现于日本琉球群岛的西表岛（284 平方公里）。由于种群规模小、分布范围有限，该物种被列入世界自然保护联盟红色名录中的濒危物种。 1994 年估计其种群数量约为 100 只，在过去十年中有所下降，主要是由于开发活动导致栖息地减少。在这里，我们重点关注两个研究地点猫的数量下降和栖息地减少；在过去的十年中，由于大规模的农业土地改革，大富地区发生了巨大的变化，而北部沿海地区除了最近的道路扩建工程外一直保持稳定。利用卫星遥感和 1984 年至 2000 年间获得的 LANDSAT TM 数据的八个场景来估计栖息地减少情况。植被覆盖状况是根据使用 IDRISI 的归一化植被指数 (NDVI) 进行评估的。使用NDVI影像创建每个时期两个地点的天然林地图；对过去17年的森林减少量和发展状况进行了估计。结果表明，大富地区森林减少主要发生在1992-1994年，同时进行了大规模的农地改革。此后，重新造林的趋势开始了。通过照片监测的常驻猫数量随着森林的减少而逐渐减少，即使在重新造林后，种群密度仍然很低。在北部沿海地区，由于森林丰富度不变，常驻猫的数量保持稳定。这表明环境的剧烈变化降低了西表猫等需要广泛栖息地的动物的承载能力。使用LANDSAT TM 的卫星遥感被认为是长期监测大面积土地覆盖的有效方法。
The Iriomote cat Prionailurus iriomotensis is a small felid found only on Iriomote Island (284 km2) of the Ryukyu Archipelago, Japan. This species is listed as an endangered species in IUCN Red list because of the small population size and the restricted distribution. Its population estimated at approximately 100 in 1994 had declined during last decade mainly due to the habitat reduction by developmental activities. Here we focused on population declines and habitat reductions of cats in two study sites; Ohtomi site has extremely changed in last decade by large-scale agricultural land reforms, while northern coastal site has been stable except recent road- expansion works. Habitat reductions were estimated using satellite remote sensing with eight scenes of LANDSAT TM data obtained between 1984 and 2000. The condition of vegetation covers were assessed based on Normalized Difference Vegetation Index (NDVI) using IDRISI. Natural forests maps of two sites in each period were created using NDVI images; the forest reductions and the status of development during past 17 years were estimated. According to the results, the forest reduction in Ohtomi site occurred particularly in 1992-1994 while large- scale agricultural land reforms were conducted. After then a trend toward reforestation had begun. Number of resident cats monitored by using photo gradually decreased with the forest reduction, and then the population density was still low even after the reforestation. In northern coastal site, number of resident cats was stable as the abundance of forest was unchangeable. It suggests that drastic change of environment has decreased carrying capacity of animal such as the Iriomote cat which requires wide range of habitat. And satellite remote sensing using LANDSAT TM is considered to be an effective method to monitor the extensive land covers during long-term period.