How does drought impact burned area in Mediterranean vegetation communities?

A Cardil; C Vega-García; D Ascoli; D M Molina-Terrén; C A Silva; M Rodrigues

doi:10.1016/j.scitotenv.2019.133603

How does drought impact burned area in Mediterranean vegetation communities?

Sci Total Environ. 2019 Nov 25:693:133603. doi: 10.1016/j.scitotenv.2019.133603. Epub 2019 Jul 27.

Authors

A Cardil¹, C Vega-García², D Ascoli³, D M Molina-Terrén⁴, C A Silva⁵, M Rodrigues⁶

Affiliations

¹ Tecnosylva Parque Tecnológico de León, 24009 León, Spain; Department of Crops and Forest Sciences, University of Lleida, Av. Rovira Roure 191, 25198 Lleida, Spain. Electronic address: acardil@tecnosylva.com.
² Department of Agricultural and Forest Engineering, University of Lleida, Lleida, Spain; Joint Research Unit CTFC - AGROTECNIO, Solsona 25280, Spain.
³ Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Braccini 2, 10095 Grugliasco, TO, Italy.
⁴ Department of Crops and Forest Sciences, University of Lleida, Av. Rovira Roure 191, 25198 Lleida, Spain; Department of Agriculture and Forest Engineering, University of Lleida, Alcalde Rovira Roure 191, 25198, Lleida, Spain.
⁵ NASA Goddard Space Flight Center, Biospheric Sciences Lab, Greenbelt, MD, USA; Department of Geographical Sciences, University of Maryland, College Park, MD, USA.
⁶ Department of Agriculture and Forest Engineering, University of Lleida, Alcalde Rovira Roure 191, 25198, Lleida, Spain; GEOFOREST Group, University Institute of Research in Environmental sciences (IUCA), University of Zaragoza, Zaragoza, Spain.

PMID: 31635012
DOI: 10.1016/j.scitotenv.2019.133603

Abstract

Drought and water stress are widely known to influence fuel moisture content and flammability, although differences do exist according to the response mechanisms and adaptive traits displayed by plant communities. In the Mediterranean basin, as a result of climate change, extreme drought events are expected to become more frequent and severe, envisaging episodes of increased fire risk. In this paper, we expand the scale of analysis on how does drought influence wildfire incidence exploring the joint influence on burned area of drought duration, magnitude and temporal distribution, and the affected vegetation communities (VCs). We leveraged the weekly adaptation of the Standardized Precipitation Evapotranspiration Index (SPEI) and historical fire perimeters to model complex interactions between drought and burned area mediated by VC composition and structure. We applied multivariate factor analysis (multi-group Principal Component Analysis) and non-parametric mixed regression models (GAMM) to a set of 1-to-48 weeks SPEI and 10 dominant VCs. We detected a significant influence of drought events (negative SPEI) on burned area, although differences in terms of seasonal distribution and VC were observed. Drought played a major role in explaining burned area in late spring and autumn by altering the usual positive rainfall-evapotranspiration balance, suggesting a potential lengthening of the fire season given the projected drought trends in the next decades.

Keywords: GAMM; Principal Component Analysis; SPEI; Wildfire.

MeSH terms

Climate Change*
Droughts*
Ecosystem*
Environmental Monitoring*
Fires*