|Wainwright, John - KINGS COLLEGE|
|Parsons, Anthony - UNIVERSITY OF LEICESTER|
Submitted to: Journal of Arid Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 1, 2005
Publication Date: April 1, 2006
Citation: Rango, A., Tartowski, S.L., Laliberte, A., Wainwright, J., Parsons, A. 2006. Islands of hydrologically enhanced biotic productivity in natural and managed arid ecosystems. Journal of Arid Environments. 65:235-252. Interpretive Summary: In order to be successful in attempting to remediate degraded rangeland, the treatments chosen should attempt to create spatial landscape patterns which are observed in arid regions. We have identified hydrologic discontinuities which are termed "islands of hydrologically enhanced biotic productivity." These are areas where excess water accumulates and causes a productive vegetation response. The naturally occurring patterns observed are banded vegetation, playettes, and beaded drainage networks. To mimic these natural features, the most successful treatment over a period of years is construction of water-ponding dikes. After a period of 20 years, these dikes are supporting grass growth in areas previously bare of vegetation. They basically do the same as nature does (vegetation bands, playettes, beads)--they slow down surface runoff and allow the water to infiltrate and increase the soil-available water, thus producing a vigorous response in a series of vegetation patches. Such rangeland treatments are relatively inexpensive and can be used by operational agencies and ranchers.
Technical Abstract: Factors causing high spatial variability of water in arid regions include precipitation, soil, physiographic, and vegetation characteristics. Inherent heterogeneity of these arid lands causes areas of runoff and run-on which develop islands of hydrologically enhanced biotic productivity. These hydrologic islands are observed at the individual plant scale as well as in large area patterns of banded vegetation, playettes and playas, and beaded drainage networks where run-on and infiltration spur vegetation growth. To remediate degraded rangeland, it may be wise to mimic nature by diverting water to target areas to create patterns similar to the natural islands of hydrologically enhanced biotic productivity or by installing structures, such as water ponding dikes, to promote a landscape change to resemble natural vegetation patterns.