Livestock, soil compaction and water infiltration rate: Evaluating a potential desertification recovery mechanism

Castellano, M. J. and Valone, T. J., 2007. Journal of Arid Environments

Original research (primary data)
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Abstract

Models predict that desertification, the loss of perennial grasses in and and semiarid environments, will be difficult to reverse due to the positive feedback between plant cover and water infiltration; reductions in plant cover concurrently reduce water infiltration to a level that is insufficient for grass growth and recruitment. Thus, a desertified state becomes stable. However, these models cannot account for recently reported perennial grass recovery in desertified habitats. Here, we suggest a novel mechanism to explain these observations: the natural increase in water infiltration rate associated with recovery from livestock-induced soil compaction. We empirically evaluate this mechanism by comparing vegetation, water infiltration rates and soil compaction at three nearby, desertified livestock exclosures that differ in time since livestock removal and perennial grass recovery; the oldest exclosure (54 years) has experienced a significant increase in perennial grasses, while there has been no such increase at the two younger exclosures (25 and 10 years). Across sites, relative differences (inside compared to outside) in water infiltration rate and soil compaction increased across each grazing fence with time since livestock removal. The relative difference in soil compaction and relative difference in water infiltration rate were significantly greatest at the sole exclosure in which perennial grasses have recovered. These data support a key aspect of desertification models: the importance of water infiltration rate for resilience of vegetation in desertified systems. Although water infiltration rate plays a critical role in understanding the stability of desertified systems, theoretical models of desertification have only incorporated plant cover as the key mechanism affecting infiltration rate. Our work suggests soil compaction may also be an important mechanism.

Case studies

Basic information

  • Case ID: INT-133-1
  • Intervention type: Combination
  • Intervention description:

    Mixed restoration/protection: Livestock exclosures

  • Landscape/sea scape ecosystem management: No
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Desertification  Positive vegetation recovery (mean basal perennial grass cover, mean shrub canopy cover, mean total vegetation), water infiltration rate, soil compaction (penetration resistance)
  • Approach implemented in the field: Yes
  • Specific location:

    San Simon Valley, Arizona, USA

  • Country: United States of America
  • Habitat/Biome type: Temperate grasslands |
  • Issue specific term: Not applicable

Evidence

  • Notes on intervention effectivness: effectiveness determined by comparing to site outside the exclosure (control) look at three sites where restoration was initiated at different times and find that "the oldest exclosure (54 years) has experienced a significant increase in perennial grasses, while there has been no such increase at the two younger exclosures (25 and 10 years). Across sites, relative differences (inside compared to outside) in water infiltration rate and soil compaction increased across each grazing fence with time since livestock removal." valid measure for ecosystem because aiming to restore grassland habitats
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Not applicable
  • Compare effectivness?: No
  • Compared to the non-NBS approach: Not applicable
  • Report greenhouse gas mitigation?: No
  • Impacts on GHG: Not applicable
  • Assess outcomes of the intervention on natural ecosystems: Yes
  • Impacts for the ecosystem: Positive
  • Ecosystem measures: Vegetation measures (mean basal perennial grass cover, shrub canopy cover, total vegetation cover
  • Assess outcomes of the intervention on people: No
  • Impacts for people: Not reported
  • People measures:
  • Considers economic costs: No
  • Economic appraisal conducted: No
  • Economic appraisal described:
  • Economic costs of alternative considered: No
  • Compared to an alternative: Not reported

Evaluation methodology

  • Type of data: Quantitative
  • Is it experimental: Yes
  • Experimental evalution done: In-situ/field
  • Non-experimental evalution done: Not applicable
  • Study is systematic: