Abstract:
High mountains possess an outstanding biodiversity compared to their surrounding lowlands and are often considered as “hotspots” of plant diversity. Especially altitude is supposed to be an important trigger: abiotic and biotic environmental factors change along the altitudinal gradient, accompanied by different disturbance regimes and dynamic processes. The thus created plant diversity must be considered in relation to the scale of observation, as mechanisms influencing diversity are often not equally effective and/or visible on different scales. Hence, a multi-scale approach is indispensable for explaining existing diversity patterns.
The study presented employs four scales of observation to reveal patterns and causes of plant diversity in the semiarid mountains of the Great Basin region: the landscape-scale covers the hole region with its single mountain ranges as a physiographical unit; the mountain-scale considers exemplary mountain ranges with their vertical zonation of climate-dependant altitudinal belts; the belt-scale is employed to describe similarities and differences of diversity patterns within these climate induced altitudinal vegetation belts; the patch-scale regards the different environmental units formed by dynamic processes within the essential communities of the various belts.
In employing this research approach, the still quite natural, relatively stable ecosystems of the Great Basin ranges are introduced, important triggers of plant diversity are described and their importance is evaluated on the different observation scales. The gained knowledge helps to understand the fundamental ecological principles of the area and is thus a valuable contribution to a basic concept for a sustainable development of the diverse Great Basin natural region.
