美国是全世界国家公园的创始国之一,早在1872年就已开办国家公园(或译国立公园)。至今全美共有40个国家公园,其中最享盛名的有黄石国家公园和落矶山国家公园(Rocky Mountain National Park)等。 通过对落矶山的实地访游,笔者对设置国家...美国是全世界国家公园的创始国之一,早在1872年就已开办国家公园(或译国立公园)。至今全美共有40个国家公园,其中最享盛名的有黄石国家公园和落矶山国家公园(Rocky Mountain National Park)等。 通过对落矶山的实地访游,笔者对设置国家公园的深远意义有了进一步认识。国家公园系以保存、恢复代表性国土的自然面貌为主要任务,并满足旅游、科普、科研等多方需要。凡能代表美国国家特色的天然风景,包括高山、大湖、深谷、冰川、冻原、火山遗迹等特殊地形、地貌及自然变迁遗迹,或古老高大的美国名木如北美红杉、巨杉(世界爷)等,和特产野生动物以及历史古迹等等。展开更多
The study intended to describe the alpine vegetation of a protected area of the northwestern Himalaya and identify the important environmental variables responsible for species distribution.We placed random plots cove...The study intended to describe the alpine vegetation of a protected area of the northwestern Himalaya and identify the important environmental variables responsible for species distribution.We placed random plots covering different habitats and altitude to record species composition and environmental variables.Vegetation was classified using hierarchical cluster analysis and vegetation-environment relationships were evaluated with Canonical Correspondence Analysis.Four communities,each in alpine shrub and meadows were delineated and well justified in the ordination plots.Indicator species for the different communities were identified.Maximum species richness and diversity were found in community IV among shrub communities and community II among the meadows.Studied environmental variables explained 61.5% variation in shrub vegetation and 59.8% variation in meadows.Soil variables explained higher variability (～35%) than spatial variables (～21%) in both shrubs and meadows.Altitude,among the spatial variables and carbon/nitrogen ratio and nitrogen among the soil variables explained maximum variation.About 40% variations left unexplained.Latitude and species diversity among the other variables had significant correlation with ordination axes.Study showed that altitude and C/N ratio played a significant role in species composition.Extensive sampling efforts and inclusion of other non-studied variables are also suggested for better understanding.展开更多
文摘美国是全世界国家公园的创始国之一,早在1872年就已开办国家公园(或译国立公园)。至今全美共有40个国家公园,其中最享盛名的有黄石国家公园和落矶山国家公园(Rocky Mountain National Park)等。 通过对落矶山的实地访游,笔者对设置国家公园的深远意义有了进一步认识。国家公园系以保存、恢复代表性国土的自然面貌为主要任务,并满足旅游、科普、科研等多方需要。凡能代表美国国家特色的天然风景,包括高山、大湖、深谷、冰川、冻原、火山遗迹等特殊地形、地貌及自然变迁遗迹,或古老高大的美国名木如北美红杉、巨杉(世界爷)等,和特产野生动物以及历史古迹等等。
文摘The study intended to describe the alpine vegetation of a protected area of the northwestern Himalaya and identify the important environmental variables responsible for species distribution.We placed random plots covering different habitats and altitude to record species composition and environmental variables.Vegetation was classified using hierarchical cluster analysis and vegetation-environment relationships were evaluated with Canonical Correspondence Analysis.Four communities,each in alpine shrub and meadows were delineated and well justified in the ordination plots.Indicator species for the different communities were identified.Maximum species richness and diversity were found in community IV among shrub communities and community II among the meadows.Studied environmental variables explained 61.5% variation in shrub vegetation and 59.8% variation in meadows.Soil variables explained higher variability (～35%) than spatial variables (～21%) in both shrubs and meadows.Altitude,among the spatial variables and carbon/nitrogen ratio and nitrogen among the soil variables explained maximum variation.About 40% variations left unexplained.Latitude and species diversity among the other variables had significant correlation with ordination axes.Study showed that altitude and C/N ratio played a significant role in species composition.Extensive sampling efforts and inclusion of other non-studied variables are also suggested for better understanding.
