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The extinction of species capable of dispersing seeds is harmful to plants. These are losing their ability to migrate to places that have not been made inhospitable by climate change, according to a new study published Thursday in the journal Science.
“When we lose birds or mammals, we don’t just lose these species. We also lose their important ecological function, which is to disperse seeds,” Evan Fricke of Rice University told AFP.
This study is the first to quantify the problem globally. She estimates that the ability of plants requiring the collaboration of animals to adapt to climate change has already been reduced by 60%.
Tree species found in areas that have become inhospitable due to global warming may, for example, migrate to others where it rains more, but must do so in the form of seeds.
Half of the plants rely on animals to eat their fruit or nuts to take them further, while others rely solely on the wind.
Previous studies used
For their work, the Danish researchers used data accumulated by thousands of previous studies on animal behavior to construct a map of their contribution to seed dispersal.
They then compared a map that negated the effect of human-caused species extinctions, and the shrinking of their territories.
Their models included many details: “Which animals eat which seeds of which fruit, how far the seeds can be moved from the original plant …”, for example listed Evan Fricke, lead author of the study.
For animals that were not specifically studied, their behavior was predicted by computer using data from similar species.
Avoiding extinctions protects the climate
The results were surprising. Seed dispersal loss was particularly marked in temperate regions of North and South America, Europe, and Australia – although they lost only a small percentage of mammalian species and d ‘birds.
The disturbance was least in the tropics of South America, Africa or Southeast Asia. However, it might accelerate if other important species go extinct, such as elephants.
The study shows that animal protection efforts can help fight climate change. “Declines in animals can disrupt ecological networks in ways that threaten the resilience of entire ecosystems,” concludes Evan Fricke.
