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Studies on spatial distribution of two invasive alien species spreading and conservation of vegetational landscape in a warm-temperate evergreen forest of the Kasugayama Forest Reserve, a World Heritage of Ancient Nara, Japan

日本古奈良世界遗产春日山森林保护区暖温带常绿森林两种外来入侵物种扩散空间分布及植被景观保护研究

基本信息

批准号：
15570024
负责人：
MAESAKO Yuri
金额：
$ 1.34万
依托单位：
Nara Saho College
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

We studied the spatial distribution of two alien species, Podocarpus nagi (Podocarpaceae) and Sapium sebiferum (Euphorbiaceae), in the Kasugayama (Mt.Kasuga) Forest Reserve (KFR), a warm-temperate evergreen forest designated a Special Natural Monument of Japan and a UNESCO World Heritage Site. We conducted field surveys and distribution mapping of these species with the aid of geographic information system (GIS) technology from 2002-2004 field data, to determine their distributions and characterize the likely invasion patterns. We recorded the locations of ca 10000 S.sebiferum plants and ca 10000 P.nagi plants (including current-year seedlings) at, respectively, using a global positioning system (GPS) in an approximately 120-ha site. Most S.sebiferum plants were aggregated in canopy gaps, whereas P.nagi tended to occur in closed canopies. High densities of P.nagi in the western part of KFR near Mt.Mikasa indicated the development of P.nagi stands. Sapium sebiferum showed no remarkable … More directional tendency in its distribution. The spatial distributions of saplings of these two alien species differed, but few differences were observed in the spatial distributions of these two species. Our results suggest that these two alien species, which originated from Mt.Mikasa and Nara Park adjacent to KFR, have expanded abundantly because of their unpalatability to deer, although they differ greatly in invasion history and spreading behavior.Additionally, we investigated bark-stripping by sika deer (Cervus nippon) in the forest at Nara Park, which is inhabited by >1200 deer. We found bark-stripping in 33.8% of 1041 trees >1.3 m in height. Among the 39 tree species recorded in 10 areas, 31 species were found to suffer various degrees of bark-stripping. Bark-stripping by sika deer depends on bark preference rather than DBH. In each plot, the proportion of tree species of low electivity increased with increasing distance from the Kasugayama Forest Reserve and/or Wakakusayama Hill. The relationship between the spatial environmental gradient and bark-stripping by sika deer suggests that regional conservation is necessary for the management of vegetation and the high-density sika deer population in Nara Park. Less

研究了春日山森林保护区（Kasugayama Forest Reserve，KFR）内2种外来树种竹柏（Podocarpus nagi）和乌桕（Sapium sebiferum）的空间分布。我们进行了实地调查和地理信息系统（GIS）技术的帮助下，从2002-2004年的现场数据，这些物种的分布图，以确定其分布和特征可能的入侵模式。我们记录了约10000 S.sebiferum植物和约10000 P.nagi植物（包括当年苗）的位置，分别使用全球定位系统（GPS）在一个约120公顷的网站。大部分S.sebiferum植物聚集在冠层间隙，而P.nagi倾向于发生在封闭的冠层。在KFR西部靠近米卡萨山的地方，长竹的密度很高，表明长竹林的发展。乌桕在生长过程中未表现出明显的 ...更多信息在分布上有一定的方向性。这两种外来树种幼树的空间分布存在差异，但两种树种的空间分布差异不大。结果表明，这两种外来物种虽然在入侵历史和扩散行为上存在很大差异，但由于其对鹿的不适应性，它们在KFR附近的米卡萨和奈良公园大量扩散。此外，我们还调查了在奈良公园的森林中西卡（Cervus nippon）剥树皮的情况，该公园有超过1200只鹿。在1041株树高> 1.3m的树木中，剥皮率为33.8%。在10个地区的39个树种中，有31个树种出现了不同程度的剥皮现象。西卡鹿剥树皮行为与树皮偏好有关，而与胸径无关。在每个样地中，低选择性树种的比例随着距离春日山森林保护区和/或若草山山的增加而增加。空间环境梯度与西卡剥皮行为的关系表明，区域保护对于奈良公园植被管理和高密度西卡种群是必要的。少