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| Titel |
Coupled local facilitation and global hydrologic inhibition drive landscape geometry in a patterned peatland |
| VerfasserIn |
S. Acharya, D. A. Kaplan, S. Casey, M. J. Cohen, J. W. Jawitz |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 5 ; Nr. 19, no. 5 (2015-05-05), S.2133-2144 |
| Datensatznummer |
250120702
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| Publikation (Nr.) |
 copernicus.org/hess-19-2133-2015.pdf |
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| Zusammenfassung |
| Self-organized landscape patterning can arise in response to multiple
processes. Discriminating among alternative patterning mechanisms,
particularly where experimental manipulations are untenable, requires
process-based models. Previous modeling studies have attributed patterning
in the Everglades (Florida, USA) to sediment redistribution and anisotropic
soil hydraulic properties. In this work, we tested an alternate theory, the
self-organizing-canal (SOC) hypothesis, by developing a cellular automata
model that simulates pattern evolution via local positive feedbacks (i.e.,
facilitation) coupled with a global negative feedback based on hydrology.
The model is forced by global hydroperiod that drives stochastic transitions
between two patch types: ridge (higher elevation) and slough (lower
elevation). We evaluated model performance using multiple criteria based on
six statistical and geostatistical properties observed in reference portions
of the Everglades landscape: patch density, patch anisotropy, semivariogram
ranges, power-law scaling of ridge areas, perimeter area fractal dimension,
and characteristic pattern wavelength. Model results showed strong
statistical agreement with reference landscapes, but only when
anisotropically acting local facilitation was coupled with hydrologic global
feedback, for which several plausible mechanisms exist. Critically, the
model correctly generated fractal landscapes that had no characteristic
pattern wavelength, supporting the invocation of global rather than
scale-specific negative feedbacks. |
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