Ecophysiological studies on the mechanisms for appearance and disappearance of species in successional stages.

机制为连续出现、替换。对日本暖温带地区常见演替过程中的3个生态场景进行了物种消失和灭绝研究。无水生境中物种的循环更替；2. 喜日乔木入侵芒草草地；3. 早期次生演替中先锋树的种子招募。对植物群落内光环境的时空异质性进行了详细的测量，以评估特定物种幼苗生长和生长的微生境分布。对入侵芒草的代表性物种锯栎（Quercus serrata）、参与Kasumigaura湖物种循环更替的水生植物Nelumbo nucifera和Nuphar japonicum，以及在森林砍伐或火灾后立即出现的典型先入者Rhus javanica和Mallotus japonica进行了生长和繁殖的各种生理和生活史参数测量。主要结果和结论是：1。水生植物异种叶的生物量分配和寿命在水生生境种内和种间竞争和二维生命空间的占据中起着重要作用。2. 芒草冠层内的光有效性存在较大的微观空间异质性。虽然具有“允许光效水平”的微场地相对丰富，但单株幼苗的生存和生长取决于微场地的光效水平。种子大、形态和生长对遮荫的响应对其成功入侵草地具有重要的生态意义。3.先锋树种种子萌发间隙检测能有效提高幼苗在间隙中的适合度。

Mechanisms for successional appearance, replacement.and disappearance of species were studied for three ecological scenes in common Successional processes in warm-temperate Japan: 1. cyclic replacement of species in anaquatic habitat; 2. invasion of heliophilic trees into Miscanthus sinensis grassland; 3. recruitment of pioneer trees from seeds in early secondary succession. Detailed measurements on temporal and micro-spatial heterogeneity of light environment within plant communities were performed to evaluate the distribution of the microsites in which seedlings of a certain species can survive and establish. Various physiological and life-history parameters associated with growth and reproduction were measured for Quercus serrata, a representative species invading into Miscanthus sinensis grassland, Nelumbo nucifera and Nuphar japonicum, the aquatic plants involving in the cyclic species-replacement in Lake Kasumigaura, and Rhus javanica and Mallotus japonica, typical pioneers appearing immediately after forest clearing or fire. The main results and conclusions are: 1. Biomass allocation and longevity of heterophylous leaves in the aquatic plants seem to play important roles in intra- and interspecific competition and occupation of two-dimensional life space in an aquatic habitat. 2. There is a great micro-spatial heterogeneity in light availability, within a Miscanthus sinensis canopy. Although, the microsites with 'Permissible light-availability levels for survival and establishment of Quercus serrata seedlings are relatively abundant, the survival and growth of the individual seedlings depend on the light availability level of the microsite. The large seed size and the morphological and growth responses to shading have important ecological significances in successful invasion of the species into the grassland. 3.Gap-detection in seed germination of pioneer tree species can effectively raise seedling fitness in gaps.