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Winter Ecological Interactions between Alpine and Subalpine Ecosystems Kate Samelson 12 March 2006 EBIO 4120 Winter Ecology – Spring 2006 Mountain Research Station – University of Colorado, Boulder Physical Environment Subalpine Alpine/Tundra Environment Environment • Elevation: 10,000 to 11,500 ft • Elevation: 11,500 ft and above • Dominated mostly by Englemann’s • Vegetation includes lichens, spruce and subalpine fir grasses, sedges, shrubs and • Precipitation: 30-35in/yr, mostly mosses. as snow • Precipitation: 6-10in/yr, including • Lingering snowpacks keep forest melted snow floor moist for much of the year • Winds can be stronger than • Deer mice, snowshoe hare, 100mph bobcats and Steller’s jays amongst • Pikas, marmots, mountain goats, other inhabit the subalpine sheep, elk and beetles all live in environment the tundra environment Organic materials and nutrients are transported via fluvial means in aquatic systems. Fluvial processes are not present in alpine environments. How are alpine and subalpine ecosystems connected if not by fluvial processes, and how does this change affect the communities?? Alpine and subalpine ecosystems are connected through groundwater and wind processes. Wind Organic materials and nutrients are transported downwind from the alpine to the subalpine. The greatest intake of organic materials and nutrients is going to be along treeline. Ecological Differences Alpine Subalpine The tundra ecosystem is The ecosystem is losing organic materials uptaking organic matter and nutrients downwind, and nutrients from and therefore the amount upwind, and therefore of organic matter being the amount organic decomposed decreases. matter being decomposed This lowers respiration is increased. This raises rates in the community. respiration rates. Primary productivity to Primary productivity to respiration ratios are >1 respiration ratios are <1 Subsurface Groundwater In alpine and subalpine ecosystems, subsurface runoff from snow can account for up to 90% of the total flow of the basin. The short residence time of water in the basin limits the ability of biota to uptake atmospherically deposited nitrogen. Conclusions Alpine and subalpine ecosystems are connected through wind processes and subsurface groundwater. Wind scouring blows nutrient and nitrogen rich snow and organic materials from the tundra into the subalpine. Productivity rates in the alpine ecosystem are decreasing, while productivity rates in the subalpine ecosystem are increasing. Groundwater interactions between the alpine and subalpine communities are often minimal and ecologically less significant. Interactions between alpine and subalpine ecosystems is of great importance to the biota of both communities and without such, the two ecosystems would be drastically different. Bibliography Liptzin, Daniel, Seastedt, Timothy, University of Colorado, Boulder, CO, USA Heterogenity in soil nutrients in the forest-alpine tundra ecotone.
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