As wildfires rage across much of southern Europe, causing death and destruction, it’s sometimes difficult to remember — and perhaps insensitive to mention — that this is in fact a common occurrence, even necessary for the maintenance of vegetation and biodiversity in the Mediterranean.
In the Mediterranean, as in the mediterraneoids, fire occurs where vegetation is flammable. Combustibility is not a misfortune but an adaptation: plants that burn do so because they are fire-adapted. They make fire-promoting resins and other chemicals, or they have structural adaptations, such as producing a loose, airy litter of dead leaves and twigs which dries out and burns. Their ecology involves catching fire from time to time and burning up competitors.
Still, one wonders whether this might be too much of a “good” thing, and whether we’re heading for even more with climate change. What will this mean for particular species, for example crop wild relatives? Do we know how many are fire-adapted? And do we know even for those that are so adapted whether beyond a certain frequency or intensity fire becomes a threat rather than a necessity?
Dear Luigi:
The adaptation to fire may be in the sense of developing structures that allow the plants to survive or even thrive in the presence of this recurrent event, fire. A different story is having structures that promote fire. Resins may have other selective contexts in which to produce greater fitness, ie defense against herbivores, quite apparent in Parastrephia in Bolivia (see my prejudices). The existence of adaptations to fire, as in the cerrado and most savannas, is clear. Greetings, dear Luigi.