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Archive for May, 2018

Ecology and Evolution in 3D or how to treat fire blindness

May 18th, 2018 No comments

The biophysical pressures shaping the ecology and evolution of species can be broadly aggregated into three dimensions [1]: environmental conditions, disturbance regimes, and biotic interactions (Fig. 1A). In many cases several of these dimensions need to be considered to adequately understand the habitat and functional traits of species when working at broad spatial or phylogenetic scales. However, it is currently common to consider only one dimension even when studying large clades, and in some cases, the dimension selected may not be the most relevant for a realistic understanding of ecological and evolutionary processes. We illustrate this problem with reference to the large and iconic plant family, Proteaceae [1]. This family can be considered the product of a long history of harsh environments, recurrent fires and strong faunal interactions (Fig. 1B). Because most Proteaceae species occur in fire-prone ecosystems and possess fire-adaptive traits that are both ancient and essential for their survival, disturbance by fire is likely to explain much of this family’s ecology, evolution, and biogeography. Thus studies of this family that are based on environmental variables only, are likely to make a poor contribution to their ecology and evolution. Failure to recognize the prominent role of fire (‘fire blindness’) is likely to result in a misunderstanding of the key evolutionary processes behind the ecological patterns. To make satisfactory progress, we need to overcome the traditional view that vegetation patterns can be explained solely through climate and soils, and to recognize plant consumers (fire & large herbivores) as potent evolutionary forces [2] and a key factor in explaining the ecology, distribution and diversity of many species [3]. In fact, I would propose to add the following term in fire glossaries and fire terminology resources:

Fire blindness: failure to recognize the prominent ecological and evolutionary role of fire in fire-prone ecosystems (Pausas & Lamont 2018). 

Figure 1: The evolutionary pressures that shape the phenotype and genotype of an organism can be aggregated into three dimensions (A): environmental factors (e.g., climate, soils, topography), disturbances, and biotic interactions; each of these dimensions is related to a particular set of traits. In the case of the Australian Proteaceae (B), the factors determining these three dimensions define the characteristics of most species (sclerophyllous species; patterned area); excluding one dimension (fire) define the few Proteaceae species that occur in non-fireprone ecosystems (dots, and figure 2 left). From [1].
 

Figure 2: Proteaceae species richness in Australia by cells of 1 degree. Left: genera in non-fire-prone vegetation (rainforest and vine forest). Right: genera in fire-prone vegetation (sclerophyll shrubland, woodland and forest, and savanna grassland). Proteaceae without fire would be confined to the rainforest fringes and depauperate in species instead of the dominant position it currently occupies throughout the Australian continent. From [1].

References

[1] Pausas J.G., Lamont B.B. 2018. Ecology and biogeography in 3D: the case of the Australian Proteaceae Journal of Biogeography. [doi | pdf]

[2] Keeley J.E., Pausas J.G., Rundel P.W., Bond W.J., Bradstock R.A. 2011. Fire as an evolutionary pressure shaping plant traits. Trends in Plant Science 16: 406-411. [doi | pdf]

[3] Pausas J.G. & Ribeiro E. 2017. Fire and plant diversity at the global scale. Global Ecology and Biogeography 26: 889–897. [doi | pdf]  

 

Marjal del Moro postfire

May 3rd, 2018 No comments

‘Marjal del Moro’ is a small coastal wetland located in the municipalities of Puçol and Sagunt (Valencia, Spain). It is a Special Area of Conservation (SAC; ZEC in Spanish) and a Special Protected Area for the conservation of birds (SPA; ZEPA in Spanish), of the European Union. In January the 4th a wildfire burned 320ha which is ca. 80% of the wetland. Here are some dynamics after the fire.

1 month after the fire (18th February 2018):

At this time, Tamarix trees (salt ceder) were not resprouting, but some other plants already started to resprout (click to enlarge):

 

4 months after fire (1st May 2018):

Note that the two trees (salt ceders, Tamarix) are the same ones from the picture above (taken in February). At this time, Tamarix species were already resprouting (click to enlarge):

 

Thanks to E. Laguna for his help on the species identification.