Archive for March, 2013

Art: fire by Chema Madoz

March 19th, 2013 No comments

I have recently visited a very nice and impressive exhibition of photographs by Chema Madoz; his photographs are visual poems. Here one that deals with fire.

A new global fire map

March 6th, 2013 2 comments

We have used remotely sensed fire information for the whole globe and aggregated this information by the WWF ecoregions, to produce an ecologically-based global fire map (figure below [1]). Using this map we have tested the intermediate fire-productivity model [2,3], i.e. that fire activity changes along the productivity/aridity gradient following a humped relationship. The results suggest that fires occur in all biomes and in nearly all world ecoregions. Fire activity peaked in tropical grasslands and savannas, and significantly decreased towards the extremes of the productivity gradient. Both the sensitivity of fire to high temperatures and the above-ground biomass increased monotonically with productivity. In other words, fire activity in low-productivity ecosystems is not driven by warm periods and is limited by low biomass; in contrast, in high-productivity ecosystems fire is more sensitive to high temperatures, and in these ecosystems, the available biomass for fires is high. The results support the intermediate fire–productivity model on a global scale and suggest that climatic warming may affect fire activity differently depending on the productivity of the region. Fire regimes in productive regions are more vulnerable to warming (drought-driven fire regime changes), while in low-productivity regions fire activity is more vulnerable to fuel changes (fuel-driven fire regime changes [4]).

Figure: An ecologically-based global fire map, from Pausas & Ribeiro (2013) [1]. The shape file is available under request [email here].

[1] Pausas J.G. & Ribeiro E. 2013. The global fire-productivity relationship. Global Ecol. & Biogeogr. 22: 728-736 [doi | pdf | erratum] - UPDATE: Paper featured by NASA.

[2] Pausas J.G. & Paula S. 2012. Fuel shapes the fire-climate relationship: evidence from Mediterranean ecosystems. Global Ecol. & Biogeogr. 21: 1074-1082. [doi | pdf | supp]

[3] Pausas J.G. & Bradstock R.A. 2007. Fire persistence traits of plants along a productivity and disturbance gradient in Mediterranean shrublands of SE Australia. Global Ecol. & Biogeogr. 330-340. [pdf | doi]

[4] Pausas J.G. & Fernández-Muñoz S. 2012. Fire regime changes in the Western Mediterranean Basin: from fuel-limited to drought-driven fire regime. Climatic Change 110: 215-226.  [doi |  pdf]



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