The ability of forests to survive and adapt to disturbances caused by climate change may depend, in part, on the eddies and eddies of global wind currents, suggests a new study by researchers at the University of California at Berkeley.
Unlike animals, the trees that make up the forests of our planet cannot uproot and find new land if conditions become harsh. Instead, many trees produce seeds and pollen designed to be blown away, an adaptation that helps them colonize new territories and maximize how well they can propagate their genes.
The new study compared global wind models with previously published genetic data from nearly 100 species of trees and shrubs collected from forests around the world, finding significant correlations between wind speed and direction and the genetic diversity in the forests of our planet. The results are the first to show that wind can not only influence the spread of genes in a tree or species, but it can also help shape genetic diversity and direct the flow of genetic variants in forests and entire landscapes.
Understanding how genetic variants move across a range of species will become increasingly important as climate change alters the conditions of local habitats, the researchers say.
“How trees move and how plants move, in general, is a large area of uncertainty in plant ecology because it is difficult to directly study plant movements – they occur as a result of small and rare movements of seeds and pollen, ”said the study’s lead author. Matthew Kling, postdoctoral fellow in integrative biology at UC Berkeley. “However, to predict how species distribution and general plant ecology will respond to climate change, we need to understand how these species will be able to travel long distances to follow the movement of natural resources and climatic conditions over time. time. . “
While animals, birds and insects can also disperse pollen and seeds, the strong directionality of the wind makes it particularly important for understanding how different tree species will respond to climate change, the lead author of the report said. study David Ackerly, professor and dean of the Rausser College of Natural at UC Berkeley. Resources.
“As the world warms, many plants and animals will need to move to places with suitable habitat in the future to survive,” Ackerly said. “Wind dispersal has a particularly interesting link with climate change because the wind can either push genes or organisms in the right direction, to a more suitable habitat, or in the opposite direction. It may be the only vector of terrestrial dispersal that can be aligned with or against the direction of climate change. “
Either way the wind is blowing
Despite the fickle nature of daily weather conditions, large-scale global wind patterns are largely determined by the shape of the Earth, the rotation and location of the continents, and are considered relatively stable over millennial time scales. These wind patterns are also unlikely to be drastically altered by climate change, Kling said.
To examine whether these prevailing global winds have shaped the genetic diversity of modern forests, Kling compared current models of planetary wind – compiled from 30 years of global wind data – with genetic data from 72 publications covering 97 tree species. and shrubs and 1940 plant populations around the world.
Kling’s analysis revealed three key ways in which global wind patterns shape the genetic diversity of forests. First, populations of trees that are connected by stronger wind currents tend to be more genetically similar than populations of trees that are not as connected. Second, populations of trees that are further downwind, or further downwind, tend to have greater genetic diversity in general. Finally, genetic variants are more likely to disperse in the direction of the wind.
While these models can only be statistically validated by examining many tree populations across the world, they can sometimes be evident when examining the genetic diversity of a single tree species in its habitat, Kling said.
For example, the island’s scrub oak, or Quercus pacifica, is native to the Channel Islands of southern California, where the prevailing winds tend to blow to the southeast. Kling’s analysis showed that brush oak populations on islands connected by higher wind speeds are genetically more similar to each other. Genetic variants also appear to have dispersed more frequently to islands in south and east directions than vice versa, leading to greater genetic diversity in the south and east.
Kling hopes that recognition of these patterns will help conservationists and environmentalists better understand how tree and plant species in different parts of the world will adapt to global warming.
“Populations in different parts of a species’ range have evolved over time to be well adapted to the climate in that specific part of the range, and as the climate changes, they can become out of sync with these conditions, ”Kling said. “It is important to understand how quickly genetic variants from other parts of the species’ range can get to where they are needed to understand how quickly the species will respond to climate change and how much a given population may be vulnerable, as opposed to resilient.
This research was funded by a National Science Foundation Research Grant.