Plant Ecology

, Volume 213, Issue 4, pp 625–635

Degraded rangeland dominated by unpalatable forbs exhibits large-scale spatial heterogeneity

  • Tomoo Okayasu
  • Toshiya Okuro
  • Undarmaa Jamsran
  • Kazuhiko Takeuchi
Article

Abstract

The spatial heterogeneity of vegetation and soil increases in response to land degradation caused by grazing mainly at a large spatial scale. This increase has been frequently associated with shrub invasion, but shrub invasion does not necessarily accompany land degradation. Instead, dominance by unpalatable forbs has been reported in some regions, but the spatial heterogeneity of such degraded rangeland has not been studied. We investigated the spatial heterogeneity of rangeland dominated by unpalatable forbs at a large spatial scale using Mongolian rangeland as an example. Spatial heterogeneity of the total vegetation cover and community heterogeneity were analyzed for three levels of land degradation. We found that the least-degraded site had homogeneous total vegetation cover and community, that the site with intermediate degradation exhibited low heterogeneity of the total vegetation cover but significant community type variation, and that the most degrade sites exhibited a periodic pattern of total vegetation cover as a result of a mixture of dense and sparse patches of unpalatable forbs. These different responses can be used to assess land degradation levels and may have potential to monitor land degradation at a large scale by satellite images.

Keywords

Land degradation Geostatistics Water runoff Grazed grassland Community heterogeneity Mongolia 

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Tomoo Okayasu
    • 1
  • Toshiya Okuro
    • 1
  • Undarmaa Jamsran
    • 2
  • Kazuhiko Takeuchi
    • 1
  1. 1.Laboratory of Landscape Ecology and Planning, Graduate School of Agricultural and Life SciencesThe University of TokyoTokyoJapan
  2. 2.Center for Ecosystem StudiesMongolian State University of AgricultureUlanbaatarMongolia

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