Forests around the world are suffering mortality due to an increase in the Frequency and intensity of drought. magazine Natural ecology and evolution recently published a study carried out by researchers from the CREAF public center with the participation of Autonomous University of Barcelonain which they present World maps It describes which forests are most at risk of dying due to a lack of water.
The forest areas of the Mediterranean basinSouth Australia, northwestern Amazonia and the United States would be most vulnerable, according to the published forecast model.
For further explanation global mappingThe researcher and his team have developed a new method that includes, in addition to data, physiological data on the strategies of thousands of species to overcome water shortages, as well as evolutionary and phylogenetic information on how adaptation to drought has evolved in the soil and climate of each biome in the world.
With this method you can “zoom out” and see that in the Mediterranean there are species that are very sensitive to lack of water and that we suffer from recurring and prolonged droughts.
The novelty of the method lies in the fact that the forest is assessed as Ecosystem The whole thing is a group of organisms that react differently to external conditions. This makes it possible to predict the effects of climate change on forests around the world on a much larger scale.
“The physiological data Based on the species, we learn that many Mediterranean trees are very well adapted to drought. Nevertheless, our model suggests that there is a very high risk of drought-related mortality in these forests. This is because our method allows us to create one Zoom out and pay attention to the fact that in this area there are also species that are very sensitive to drought and that we suffer from recurrent and prolonged droughts,” he explains. Pablo Sanchez-MartínezLead author of this study, which also includes Maurizio Mencuccini and Jordi Martínez-Vilalta.
Trees that are like camels
When trees die due to extreme droughts, it is generally because the water in the trunk cannot circulate well because its pipes (so-called Xylem) They lose strength or become clogged, a process known as “hydraulic failure‘.
Science knows physiological parameters that tell us whether a species or tree is more or less protected from this hydraulic failure. One of the most relevant is the “hydraulic safety marginThis is what separates the amount of water the tree can mobilize during drought from the minimum amount of water it needs to survive.
How Camels, there are trees that have a lot of scope and can withstand the lack of water because they store it and need little to live. However, there are other species that are not adapted to these conditions, making them very vulnerable to periods without humidity.
Physiological data like this is key to understanding which forests are most at risk of water damage and drought die-off. This is undoubtedly very useful information, but with restrictionswhich is now included in this new model.
If we knew this data for all plant species in the world, we could make more accurate predictions. However, data is only available for this parameter 1.5% of all plant species of the world.
“This study presents for the first time a Overall characterization of forest mortality risk, but there is still much to be done. The predictions proposed in this article are a first step that will need to be supplemented and improved in the near future,” concludes Pablo Sánchez.