Study in 'Nature' shows that plants in dry zones adopt different adaptation strategies

An international study conducted by Alexandra Rodríguez, Helena Castro, and Jorge Durán, researchers at the CFE, shows that plants in dry areas adopt many different adaptation strategies and that this diversity increases with aridity levels.

Just published in the prestigious Nature magazine, this study involved 120 scientists from 27 countries with the aim of understanding how plants found in arid lands have adapted to these extreme habitats. Over eight years, scientists collected samples from several selected dryland plots on six continents.

According to Helena Castro, «the isolation of these plants in more arid areas appears to have reduced competition between species, allowing them to express a diversity of forms and functions globally unique, exhibiting twice the diversity found in more temperate zones».

«This study sheds new light on our understanding of plant architecture, plant adaptation to extreme habitats, historical colonization of plants in terrestrial environments and the ability of plants to respond to current global changes», considers Alexandra Rodríguez.

Scientists collected and processed samples of 301 plant species found in 326 representative plots of all continents (except Antarctica) to characterize the functional diversity of the zones, generating 1347 complete sets of trait observations for analysis.

Initially, researchers thought that aridity would reduce plant diversity through selection, leaving only those species capable of tolerating extreme water shortages and heat stress. However, experts have discovered that in the driest areas of the planet, plants exhibit a wide range of adaptation strategies.

«For example, some plants have developed high calcium levels, strengthening cell walls as protection against desiccation. Others contain high concentrations of salt, reducing sweating. Although fewer species are observed on a local scale compared to other regions of the planet, plants in arid areas exhibit an extraordinary diversity of shapes, sizes and functioning», guarantees Jorge Durán.

This increase in trait diversity occurs abruptly at the point where rainfall decreases from the annual limit of 400 mm. This is also the threshold for a pronounced decline in vegetation cover and the emergence of large areas of bare soil. To explain this phenomenon, the study authors suggest that the loss of vegetation cover leads to the syndrome of plant loneliness, in which increased isolation and reduced competition for resources produce high degrees of trait uniqueness and functional diversity that are globally exceptional.

«This study reveals the importance of drylands as a global reservoir of plant functional diversity, providing a new lens through which we can view plant architecture, the adaptation of plants to extreme habitats, the historical colonization of plants in terrestrial environments, and the plants' ability to respond to current global changes», conclude the experts.

The scientific article "Unforeseen plant phenotypic diversity in a dry and grazed world" can be consulted here.