ASTER and Ground Observations of Vegetation Primary Succession and Habitat Development near Retreating Glaciers in Alaska and Nepal
Abstract
Like active volcanoes, glaciers are among the most dynamic components of the Earth's solid surface. All of the main surface processes active in these areas have an ability to suddenly remake or "resurface" the landscape, effectively wiping the land clean of vegetation and habitats, and creating new land surface and aqueous niches for life to colonize and develop anew. This biological and geomorphological resurfacing may remove the soil or replace it with inorganic debris layers. The topographical, hydrological, and particle size-frequency characteristics of resurfaced deglaciated landscapes typically create a high density of distinctive, juxtaposed niches where differing plant communities may become established over time. The result is commonly a high floral and faunal diversity and fecundity of life habitats. The new diverse landscape continues to evolve rapidly as ice-cored moraines thaw, lakes drain or fill in with sediment, as fluvial dissection erodes moraine ridges, as deltaic sedimentation shifts, and other processes (coupled with primary succession) take place in rapid sequence. In addition, climate dynamics which may have caused the glaciers to retreat may continue. We will briefly explore two distinctive glacial environments-(1) the maritime Copper River corridor through the Chugach Mountains (Alaska), Allen Glacier, and the river's delta; and (2) Nepal's alpine Khumbu valley and Imja Glacier. We will provide an example showing how ASTER multispectral and stereo-derived elevation data, with some basic field-based constraints and observations, can be used to make automatic maps of certain habitats, including that of the Tibetan snowcock. We will examine geomorphic and climatic domains where plant communities are becoming established in the decades after glacier retreat and how these link to the snowcock habitat and range. Snowcock species have previously been considered to have evolved in close association with glacial and tectonic history of South and Central Asia (B. An et al., 2009, Molecular Phylogenetics and Evolution 50: 526-533; R. Luzhang et al., 2010, Animal Biology 60: 449-465). The new maps and some observations of the snowcock's habits, ecological relationships to other species and landscapes, and physiological limitations support that basic model. Our new data and mapping carries some profound implications for past, present, and future coevolution of these birds and glaciers. Using insights derived from ASTER remote sensing based habitat mapping, we will explore some specific processes that may drive snowcock habitat, population, and genetic dynamics. Although the ecological fabric differs from one region to another, some basic insights from the Himalayan Khumbu valley may be applied to the Chugach Range.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.C43A..09K
- Keywords:
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- 0444 BIOGEOSCIENCES / Evolutionary geobiology;
- 0476 BIOGEOSCIENCES / Plant ecology;
- 0480 BIOGEOSCIENCES / Remote sensing;
- 0720 CRYOSPHERE / Glaciers