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A Quaternary geoecological study on disturbance regime and vegetation structure in volcanic areas

火山区第四纪扰动机制及植被结构的地质生态研究

基本信息

批准号：
17500705
负责人：
TAKAOKA Sadao
金额：
$ 2.14万
依托单位：
Senshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

Landform evolution can cause changes in habitat environments even on a geological time scale, keeping vegetation landscape in disequilibrium state for a long period of time. It is important to clarify landform effects on vegetation over a timescale of centuries and millennia, as well as at a timescale of years and decades. The structure and causal factors of vegetation boundaries were studied on Mounts Daisen, Yakedake, and Abo to clarify the long-term influences of mountain evolution on vegetation. On Mount Daisen, a distinct forest line formed at between 1100- and 1300-m elevation, which coincided with the geological boundary of the lava dome and talus deposits. No forest stands were able to develop on the summit lava dome because of poor soil development, and the position of the forest line was controlled not by macroclimatic or topoclimatic conditions but rather by the immature soils on the lava dome that formed during the late Pleistocene to early Holocene. In the Yakedake-Abo area, a subalpine-montanous forest boundary formed at between 1100- and 1700-m elevation, which coincided with the landform boundary of the smooth and dissected slopes. On steep slopes created by post-glacial dissection, frequency of canopy-gap formation is higher. This may cause broad-leaved trees to establish at the elevation of altitudinal limit of the distribution. In some cases, boulder cover prevents broad-leaved trees from establishing on smooth slopes. Post-glacial dissection has removed the boulder cover, improving edaphic conditions. These suggest that the vegetation boundary has been developed along with post-glacial slope dissection in the Yakedake-Abo area.

即使在地质时间尺度上，地貌演变也会引起生境环境的变化，使植被景观长期处于不平衡状态。重要的是要弄清几个世纪和几千年的时间尺度上的地形对植被的影响，以及几年和几十年的时间尺度上的影响。为了阐明山地演化对植被的长期影响，对代森山、亚克达克山和阿博山的植被边界结构和成因进行了研究。在代森山上，在海拔1100米到1300米之间形成了一条独特的林线，这条线与熔岩穹顶和距骨矿床的地质边界重合。由于土壤发育不良，顶端熔岩穹顶上不能发育森林，林线的位置不受宏观气候或地形气候条件的控制，而是受晚更新世至全新世早期熔岩穹顶上形成的未成熟土壤的控制。在雅克达克-阿博地区，在海拔1100-1700m之间形成了一条亚高山-山地森林边界，这与光滑和解剖的斜坡的地貌边界相吻合。在冰川后解剖形成的陡峭斜坡上，树冠缺口形成的频率较高。这可能会导致阔叶树在分布的海拔极限处建立。在某些情况下，巨石覆盖会阻止阔叶树在平坦的山坡上生长。冰川后的解剖移除了巨石覆盖，改善了土壤条件。这些都表明，雅克达克-阿博地区的植被边界是随着冰期后的斜坡解剖而形成的。