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Tom Pugh

Thomas Pugh

Senior lecturer

Tom Pugh

Delayed and altered post-fire recovery pathways of Mediterranean shrubland under 20-year drought manipulation

Author

  • Daijun Liu
  • Chao Zhang
  • Romà Ogaya
  • Marc Estiarte
  • Xiwen Zhang
  • Thomas A.M. Pugh
  • Josep Peñuelas

Summary, in English

Increasing water deficits and severe droughts are expected to alter the dynamics of vegetation post-disturbance recovery by decreasing new recruitment and limiting growth in semi-arid Mediterranean ecosystems in future. However, which vegetation metrics will be shifted and how they respond over time are not clear, and the experimental evidence is still limited. Here we assessed the impacts of a long-term (20 years) experimental drought (−30% rainfall) on the pathways of vegetation metrics related to species richness, community composition and abundance dynamics for an early-successional Mediterranean shrubland. The results indicate that the pathways of vegetation metrics were differently affected by experimental drought. The abundance of Globularia alypum follows pathway 1 (altered mature state). Simpson diversity and abundance of Erica multiflora follow pathway 2 (delayed succession) while species richness, community abundance and shrub abundance follow pathway 3 (alternative stable state). There were no significances for the resilience to extremely dry years (the ratio between the performance after and before severe events) between control and drought treatment for all vegetation metric. But, their resilience for the metrics (except Simpson diversity) to extremely dry years in 2016–17 were significantly lower than that of 2001 and of 2006–07, possibly caused by the severe water deficits in 2016–17 at mature successional stage. Principal component analysis (PCA) shows that the first two principal components explained 72.3 % of the variance in vegetation metrics. The first axis was mainly related to the changes in community abundance, shrub abundance and species richness while the second axis was related to Simpson diversity and abundance of G. alypum and E. multiflora. Principal component scores along PC1 between control and drought treatment were significantly decreased by long-term experimental drought, but the scores along PC2 were not affected. Further research should focus on successional pathways in more water-deficit conditions in Mediterranean ecosystems and the consequences of changes in vegetation recovery pathways on ecosystem functions such as biomass accumulation and soil properties.

Department/s

  • MERGE: ModElling the Regional and Global Earth system
  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • Dept of Physical Geography and Ecosystem Science

Publishing year

2022-02-15

Language

English

Publication/Series

Forest Ecology and Management

Volume

506

Document type

Journal article

Publisher

Elsevier

Topic

  • Physical Geography

Keywords

  • Abundance dynamics
  • Climate change
  • Community composition
  • Long-term drought experiment
  • Mediterranean shrublands
  • Species diversity
  • Succession pathways
  • Vegetation metric space

Status

Published

ISBN/ISSN/Other

  • ISSN: 0378-1127