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

本文研究了龙须草(Pdocarpaceae)和乌鸦(Sapium Sebiferum)两种外来物种在鹿儿山森林保护区(Kfr)的空间分布。利用2002-2004年的野外数据，利用地理信息系统(GIS)技术对这些物种进行了实地调查和分布图绘制，以确定它们的分布和可能的入侵模式。我们利用全球定位系统(Gps)在约120hm2的场地上分别记录了约10000株乌骨茶和约10000株南瓜(包括当年苗)的位置。白花蛇舌草大多聚集在林窗内，而南瓜多集中在封闭式林冠内。在KFR西部靠近Mikasa山的地方，P.nagi的高密度表明了P.nagi林的发育。乌鸦没有显著的…在分布上有更多的方向性。两种外来树种的幼树在空间分布上存在差异，但在空间分布上差异不大。我们的结果表明，这两个外来物种起源于米卡萨山和奈良公园，因为它们不喜欢鹿，尽管它们在入侵历史和传播行为上有很大的不同。此外，我们调查了奈良公园森林中梅花鹿(Cervus Nippon)对树皮的剥离，那里居住着&GT；1200鹿。在1041株树高1.3m中，有33.8%的树出现了剥皮现象。在10个地区记录的39个树种中，有31个树种受到不同程度的剥皮。梅花鹿剥皮取决于树皮偏好，而不是胸径。在每个样地中，低选择性树种的比例随着距离鹿儿山森林保护区和/或和歌山山的距离的增加而增加。空间环境梯度与梅花鹿剥皮之间的关系表明，对于奈良公园的植被和高密度梅花鹿种群的管理，区域保护是必要的。较少

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