Ecosystems

, Volume 12, Issue 3, pp 434–444

Post-Fire Resource Redistribution in Desert Grasslands: A Possible Negative Feedback on Land Degradation

  • Sujith Ravi
  • Paolo D’Odorico
  • Lixin Wang
  • Carleton S. White
  • Gregory S. Okin
  • Stephen A. Macko
  • Scott L. Collins
Article

DOI: 10.1007/s10021-009-9233-9

Cite this article as:
Ravi, S., D’Odorico, P., Wang, L. et al. Ecosystems (2009) 12: 434. doi:10.1007/s10021-009-9233-9

Abstract

Desert grasslands, which are very sensitive to external drivers like climate change, are areas affected by rapid land degradation processes. In many regions of the world the common form of land degradation involves the rapid encroachment of woody plants into desert grasslands. This process, thought to be irreversible and sustained by biophysical feedbacks of global desertification, results in the heterogeneous distribution of vegetation and soil resources. Most of these shrub-grass transition systems at the desert margins are prone to disturbances such as fires, which affect the interactions between ecological, hydrological, and land surface processes. Here we investigate the effect of prescribed fires on the landscape heterogeneity associated with shrub encroachment. Replicated field manipulation experiments were conducted at a shrub-grass transition zone in the northern Chihuahuan desert (New Mexico, USA) using a combination of erosion monitoring techniques, microtopography measurements, infiltration experiments, and isotopic studies. The results indicate that soil erosion is more intense in burned shrub patches compared to burned grass patches and bare interspaces. This enhancement of erosion processes, mainly aeolian, is attributed to the soil–water repellency induced by the burning shrubs, which alters the physical and chemical properties of the soil surface. Further, we show that by enhancing soil erodibility fires allow erosion processes to redistribute resources accumulated by the shrub clumps, thereby leading to a more homogeneous distribution of soil resources. Thus fires counteract or diminish the heterogeneity-forming dynamics of land degradation associated with shrub encroachment by enhancing local-scale soil erodibility.

Key words

land degradationdrylandssoil erosionfirewater repellencyshrub encroachment

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Sujith Ravi
    • 1
  • Paolo D’Odorico
    • 2
  • Lixin Wang
    • 3
  • Carleton S. White
    • 4
  • Gregory S. Okin
    • 5
  • Stephen A. Macko
    • 2
  • Scott L. Collins
    • 4
  1. 1.B2 Earthscience & UA Biosphere 2University of ArizonaTucsonUSA
  2. 2.Department of Environmental SciencesUniversity of VirginiaCharlottesvilleUSA
  3. 3.Department of Civil and Environmental EngineeringPrinceton UniversityPrincetonUSA
  4. 4.Department of BiologyUniversity of New MexicoAlbuquerqueUSA
  5. 5.Department of GeographyUniversity of CaliforniaLos AngelesUSA