Interactions between biological invasion and scale-dependent environments in the early stages of succession

生物入侵是指非本土物种通过人类活动在自然生态系统中生存。特别是，BC在演替的早期阶段对严重干扰的群落是显著的。这种机制与从微地形到景观的各种空间尺度有关。本研究比较了BC不明显的USU山和BC明显的科马山植物群落，以阐明不同环境尺度的本地和非本地物种之间的显著差异。发表的论文摘要如下：1)在1996年喷发后的科马山和USU火山上，营养繁殖对植被恢复的贡献大于有性繁殖。此外，微地形是决定群落发展的重要因素。2)菌根定植随海拔梯度不同而不同。我确认了一些尚未报道的维管束植物是被菌根接种的。菌根对落叶松生长的贡献率较低。3)种子库存活和萌发特性的时间变化与所经历的环境有很大关系，如温度波动。4)BC树种具有较高的形态可塑性，能较好地适应大风、干旱、低营养等各种干扰和胁迫，具有较高的存活率。在此基础上，对不同尺度间的相互作用进行了自上而下和自下而上的分析。通过这笔赠款购买的科马山气象站已经测量了天气状况。结合这些结果，我完成了不同生活史阶段(种子传播、萌发、建立和生长)在某些环境梯度下的相互作用的量化，例如地表湿度和微地形。

Biological invasion (BC) means that non-native species establishes in natural ecosystems via human impacts. In particular, BC is remarkable on severely-disturbed communities in the early stages of succession. The mechanisms are related to various spatial scales from microtopography to landscape. This study compares plant communities between Mount Usu where BC is not conspicuous and Mount Koma where BC is conspicuous, to clarify the significant differences between native and non-native species with different environmental scales. The abstracts of published papers are as follows : 1) On Mount Koma after the 1996 eruptions as well as Mount Usu, vegetative reproduction contributes revegetation more than sexual reproduction. In addition, microtopography is important to determine the community development. 2) Mycorrhizal colonization differs along elevational gradient. I confirmed that a few vascular plant species that have not been reported were inoculated by mycorrhiza. The contribution of mycorrhiza on the growth of larch was low. 3) Temporal changes in the characteristics of survival and germination on seedbank are greatly related to the experienced environments, such as temperature fluctuations. 4) BC species have higher survival rates than native species by higher morphological plasticity adapted to various disturbances and stresses, such as strong wind, drought and low nutrients.Based on those results, top-down and bottom-up analyses have been conducted on the interactions between different scales. Weather conditions have been measured by weather stations purchased by this grant on Mount Koma. By the combinations of those results, I completed that the quantification of the interactions on various life history stages (seed dispersal, germination, establishment and growth) under certain environmental gradients, e.g., ground surface moisture and microtopography.