Aleutian Dwarf Scrub Volcanics
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
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Transition T1a
Introduction of Grazing
More details -
Transition T3A
Time
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
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Description
The Reference State (State 1) is a complex of slopes, depressions, and plateaus that are volcanic cones and lava flows. This complex includes the scars from frost and solifluction, that have created barren soil patches with sparse vegetative cover. The prominent cover is a scrub matt with dwarf shrubs, herbaceous forbs and intermixed sedge and grasses. Mosses and lichens are an important component of this community. Overall ground cover of vegetation averages 20 to 40 percent. The ground not under vegetation has a pebbly/cobbly/stoney surface cover. Within this complex, depressions and protected pockets are wet from snow bed melt and precipitation runoff, creating small meadow areas dominated with willows and increased sedges and grasses. This complex of sites is very inter-related and although uniquely different, are difficult to separate into unique ecological sites. With increased data collection and smaller scaled soils maps, this ecological complex will be re-evaluated.
Submodel
Description
Caribou and managed herds of reindeer are common to certain Aleutian Islands. Small herds of cattle are also found on some islands. The grazing of these higher land tundra is common during the winter especially but are utilized year-round. The pressure on these tundra communities causes degradation over time, losing desirable lichen cover and other sedge and grass communities, reducing overall cover and vigor of the community. The change in vegetation leads to soil movement by wind and by water movement over the surface.
Submodel
Description
The volcanic activity across the Aleutian Islands is still a common occurrence. The successional phases of recovery of the recent deposits of lava and exposed or deposited cinder blocks are a slow but extremely important system within the Aleutian Chain. Although there is very little to no data available on this process from the Aleutians, the State is being captured with preliminary information.
Submodel
Mechanism
Introduced herds of reindeer, cattle and other animals has removed higher levels of desirable species as well as created soil disturbance (compaction and churning by hoof action). Increased human activity also shifts the natural patterns of use placing higher pressure on select locations.
Mechanism
Given time, under the harsh climate conditions, the volcanic deposited lava and materials will weather and begin to form soil. As fractures and sediment deposits accumulate with the weathered rock, plants will begin to colonize. Time required will be highly variable.
Model keys
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Ecological sites
Major Land Resource Areas
The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.