Arctic polygon complex
Scenario model
Current ecosystem state
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Management practices/drivers
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- Transition T1 More details
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No transition or restoration pathway between the selected states has been described
Target ecosystem state
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Description
This state relates to low-centered ice wedge polygon, which are polygon whose center is depressed relative to its boundary. There are three associated plant communities related to polygon microtopography in this state: low-center of the polygon (community 1.1), adjacent rim (community 1.2), and the ice wedge trough (community 1.3). The polygon center and trough are often perennially ponded with shallow water and supports a wet graminoid herbaceous community dominated by various sedges. The polygon center is surrounded by a raised rim that supports open low scrub communities dominated by scrub birch, various ericaceous scrubs, willow, and various sedges.
The depth of ponded water in the polygon center likely plays a critical role in plant species composition but was not accounted for during development of this provisional state and transition model.
Submodel
Description
This state relates to high-centered ice wedge polygon and these are polygon whose center is raised relative to its boundary. There are two associated plant communities related topolygon microtopography in this state: domed center of the polygon (community 1.1) and ice wedge trough (community 1.2). The troughs are often perennially ponded with shallow waterand supports a wet graminoid herbaceous community dominated by various sedges. The polygon dome supports ericaceous dwarf scrub communities dominated by lingonberry, marshLabrador tea, various sedges, and various moss.
Submodel
Mechanism
thermal erosion of ice wedges
Context dependence
Thermal erosion of ice wedges and/or infilling of low-center results in the transformation of low-center polygon to high-center polygon. This is a natural process that can take thousands of years. Climate change and anthropogenic disturbances to associated soils can much more rapidly cause thermal erosion of ice wedges and cause this transformation.
Model keys
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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.