When we lose birds or mammals, we don’t just lose those species. We also lose their important ecological function, which is to disperse seedsRice University’s Evan Fricke told AFP.
This study is the first to quantify the problem at the global level, and estimates that the ability to adapt to climate change of plants requiring the collaboration of animals has already been reduced by 60%.
Tree species present in regions that have become inhospitable due to global warming can, 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 fruits or nuts and thus carry them away, while others rely solely on the wind.
For their work, the Danish researchers used data accumulated from thousands of previous animal behavior studies to build a map of their contribution to seed dispersal.
They then compared a map canceling the effect of species extinctions caused by humans, and the reduction 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 have not been specifically studied, their behavior was predicted by computer using data from similar species.
The results were surprising. Loss in seed dispersal was particularly marked in temperate regions of North and South America, Europe, and Australia – even though they had lost only a small percentage of mammalian species and ‘birds.
Disturbance was less in tropical regions of South America, Africa or Southeast Asia. However, it could accelerate if other important species become extinct, such as elephants.
The study shows that animal protection efforts can help combat climate change.
Declines in animals can disrupt ecological networks in ways that threaten the resilience of entire ecosystems, concludes Evan Fricke.