A test of critical thresholds and their indicators in a desertification-prone ecosystem: more resilience than we thought

Ecology Letters
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Abstract

Theoretical models predict that drylands can cross critical thresholds, but experimental manipulations to evaluate them are non-existent. We used a long-term (13-year) pulse-perturbation experiment featuring heavy grazing and shrub removal to determine if critical thresholds and their determinants can be demonstrated in Chihuahuan Desert grasslands. We asked if cover values or patch-size metrics could predict vegetation recovery, supporting their use as early-warning indicators. We found that season of grazing, but not the presence of competing shrubs, mediated the severity of grazing impacts on dominant grasses. Recovery occurred at the same rate irrespective of grazing history, suggesting that critical thresholds were not crossed, even at low cover levels. Grass cover, but not patch size metrics, predicted variation in recovery rates. Some transition-prone ecosystems are surprisingly resilient; management of grazing impacts and simple cover measurements can be used to avert undesired transitions and initiate restoration.
Publication type Article
Publication Subtype Journal Article
Title A test of critical thresholds and their indicators in a desertification-prone ecosystem: more resilience than we thought
Series title Ecology Letters
DOI 10.1111/ele.12045
Volume 16
Issue 3
Year Published 2013
Language English
Publisher Wiley
Publisher location Hoboken, NJ
Contributing office(s) Southwest Biological Science Center
Description 7 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Ecology Letters
First page 339
Last page 345
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