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Complex structural effects of two hemispheric climatic oscillators on the regional spatio-temporal expansion of a threatened bird

Blue-billed duck
escapes extinction,
to find a small kid
Partial observability
Structural Equation Modelling
threatened species
Stochasticity
Climatic fluctuations

Pablo Almaraz, Juan A. Amat (2004) Complex structural effects of two hemispheric climatic oscillators on the regional spatio-temporal expansion of a threatened bird. Ecology Letters 7: 547–556, DOI: 10.1111/j.1461-0248.2004.00612.x

Authors
Affiliations

Pablo Almaraz

ICMAN-CSIC

Juan A. Amat

EBD-CSIC

Published

June 2004

Doi

10.1111/j.1461-0248.2004.00612.x

Abstract

Links between climatic conditions in the eastern equatorial Pacific and extratropical ecological processes remain unexplored. The analysis of a 20-year time series of spatial and numeric dynamics of a threatened Mediterranean bird suggests, however, that such couplings can be remarkably complex. By providing a new ecological time-series modelling approach, we were able to dissect the joint effects of the El Niño/Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), regional weather, population density and stochastic variability on the expansion dynamics of the White-headed duck (Oxyura leococephala) in Spain. Our results suggest that the spatial and numeric dynamics of ducks between peak brood emergence and wintering were simultaneously affected by different climatic phenomena during different phases of their global cycles, involving time lags in the numeric dynamics. Strikingly, our results point to both the NAO and the ENSO as potentially major factors simultaneously forcing ecological processes in the Northern Hemisphere, and suggest a new pathway for non-additive effects of climate in ecology.

Important figure

Diagram of the full structural equation model depicting the large-scale climatic effects on O. leucocephala spatio-temporal dynamics through regional weather variability. The modelled spatial downscaling follows logically from the upper part of the graph to the lower part. Each box in the graph depicts a variable (modelled indicator if solid, unobserved latent if dotted) and each arrow depicts a causal relationship (if single-headed) or a simultaneous covariance (if double-headed) between the set of indicators (if solid) and constructs (if dotted). The ovals stand for the structural perturbation term of each endogenous variable. See the main text and Appendix S1 in the Supplementary Material for parameters and further descriptions.

Citation

 Add to Zotero 

@article{Almaraz2004,
  title = {Complex Structural Effects of Two Hemispheric Climatic Oscillators on the Regional Spatio-Temporal Expansion of a Threatened Bird},
  author = {Almaraz, Pablo and Amat, Juan A.},
  date = {2004-06-04},
  journaltitle = {Ecology Letters},
  volume = {7},
  number = {7},
  pages = {547--556},
  doi = {10.1111/j.1461-0248.2004.00612.x}
}