Birds, in particular, are severely under threat because their bodies make it difficult to naturally adjust to warming temperatures. Some scientists suggest that the number of bird deaths may be approaching a second “Silent Spring”, echoing the mass die-off of birds due to the pesticide DDT in the 1960s.
But some migrating birds are trying their best to help the planet cope with the worsening climate crisis, according to new research published Wednesday in the journal Nature.
How are animals adapting to the climate crisis?
What’s new — Unlike humans, who can put together an arsenal of super-technology — like devices that suck carbon from the atmosphere — animals don’t have many tools at their disposal to fight the climate crisis.
Instead, they can execute one of three strategies, according to the Columbia Climate School:
- Move to a new environment
- Die out
- Adapt to changing circumstances
Some animals are taking the final option, dealing with the climate crisis through adaptive strategies like changing their body temperatures and finding cooler habitats in order to increase their chances of survival.
Other animals are reconfiguring their bodies in order to survive. For example, research published in 2020 found that birds are getting smaller and mammals getting larger in areas most affected by the climate crisis.
This strategy is known as “phenotypic plasticity” and it allows animals to handle unexpected environmental stress, such as warming temperatures due to the climate crisis.
But not all of these coping strategies are productive in the long run for the planet, as the Nature study underscores — despite the animal’s best intentions.
What’s new — A study conducted by 18 researchers from 13 European institutions found that migrating birds carry seeds south toward hotter environments wracked by the climate crisis.
Migrating birds are significant for many plant ecosystems, as they eat and then carry plant seeds in their gut far beyond a plant’s native habitat — some, as the study notes, more than 100 miles away.
But if the birds transport the seeds far enough north, they could theoretically disperse the plants to cooler habitats better suited to weather the climate crisis.
“Contemporary climate change is so fast that many plants require dispersal distances far beyond those that normally take place locally,” lead author Juan Pedro González-Varo, of the University of Cádiz, said in an emailed press statement.
That’s not currently happening. Instead, scientists found that birds migrating south in the autumn carried 86 percent of plant seeds in the study. Conversely, birds migrating in the spring to cooler northern climates in the fall only carried 35 percent of the seeds.
Furthermore, the northward-migrating birds come from only a handful of species, whose migration patterns are already under threat due to the climate crisis. These bird species include:
- Song thrushes
- European robins
“We believe that our study gives added value to these species since they would be responsible for helping European plant communities respond to climate change,” González-Varo says.
How they did it — Researchers combined data on bird migration with existing data on interactions between birds and fleshy-fruited plants from 13 different European woodland environments. These plants include common varieties such as juniper and ivy.
This data allows the scientists to determine the number of seeds that each bird species disperses and the direction the birds migrate: north or south. From there, the scientists figured out that more seed-carrying birds were flying south rather than north.
Why it matters — The climate crisis is already devastating European woodlands. More than 50 percent of European forests are at risk of severe forest fires and insect attacks due to global warming.
Birds that migrate northward could theoretically help these plants survive in new ecosystems not wracked by the climate crisis. These ecosystems tend to be in cooler northern climates that are less affected by global warming.
The researchers write:
Notably, the key bird species for plant dispersal towards cooler latitudes are — in general — common and abundant birds, highlighting their importance for the functioning and dynamics of ecological communities.
However, as the study shows, most of the seeds are being carried and dispersed by birds migrating south — not north.
The birds’ current southward migration patterns limit their ability to disperse plants to new areas where they might thrive during the climate crisis. According to the study, only one-third of European fleshy-fruited plant species will benefit from the current birds migrating northward.
Ultimately, birds’ current migration patterns cannot help plantlife overcome the climate crisis alone, the research suggests. If we don’t do anything to halt the rapid warming of the planet, our inaction could have devastating consequences for the survival of plant life, especially in Europe’s forests.
However, there is a positive takeaway: migrating birds can help scientists understand how seeds — particularly from plants affected by the climate crisis — are being carried around the world.
What’s next — Due to their ability to disperse seeds, migrating birds are becoming an essential tool for scientists to track the effects of the climate crisis on different ecosystems.
Scientists in this study hope to use advancing GPS technology to better track where birds migrate and disperse seeds.
With these findings in hand, scientists now have a new model to track how the worsening climate crisis is affecting ecosystems around the world — with the help of a few of our bird friends.
Abstract: Climate change is forcing the redistribution of life on Earth at an unprecedented velocity. Migratory birds are thought to help plants to track climate change through long-distance seed dispersal. However, seeds may be consistently dispersed towards cooler or warmer latitudes depending on whether the fruiting period of a plant species coincides with northward or southward migrations. Here we assess the potential of plant communities to keep pace with climate change through long-distance seed dispersal by migratory birds. To do so, we combine phenological and migration information with data on 949 seed-dispersal interactions between 46 bird and 81 plant species from 13 woodland communities across Europe. Most of the plant species (86%) in these communities are dispersed by birds migrating south, whereas only 35% are dispersed by birds migrating north; the latter subset is phylogenetically clustered in lineages that have fruiting periods that overlap with the spring migration. Moreover, the majority of this critical dispersal service northwards is provided by only a few Palaearctic migrant species. The potential of migratory birds to assist a small, non-random sample of plants to track climate change latitudinally is expected to strongly influence the formation of novel plant communities, and thus affect their ecosystem functions and community assembly at higher trophic levels