Gradients, vegetation and climate: spatial and temporal dynamics in the Olympic Mountains, U.S.A.
The steep environmental gradients of mountains result in the juxtaposition of diverse vegetation associations with narrow ecotones because life zones are compressed. Variation in geologic substrate, landforms, and soils, in combination with steep environmental gradients, create habitat diversity across spatial scales from 106 ha to <10 m2. This leads to higher biodiversity in a smaller space than in landscapes with less topographic variation. Mountains are often considered to be refuges for biological diversity at the regional scale, although variation in landscape features creates refuges at a fine scale as well. Mountains should also be considered a source of biological diversity, because they provide the germplasm for migration into lowland areas following glacial recession. Many taxa are distributed over a broad range of elevations and habitats, which maximizes the potential to respond to environmental perturbations. Reorganization of species distribution and abundance as a result of climatic change may be impacted considerably by human-caused fragmentation of landscape features, especially at lower elevations. This paper uses palaeoecological and biogeographical data to investigate the spatial and temporal vegetation dynamics of a steep maritime range, the Olympic Mountains (USA). The role of resource management in protecting vegetation in a fragmented landscape is discussed, with emphasis on how to address uncertainties such as climatic change.
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global climate change;
plant species distribution
Document Type: Research Article
Cooperative Park Studies Unit, University of Washington, Box 352100, Seattle, WA 98195, U.S. Geological Survey, Olympic Field Station, 600 E. Park Ave., Port Angeles, WA 98362 and 1127 W. 7th, Port Angeles, WA 98362, U.S.A.
Publication date: January 1, 1997