Climate change: Danger for the vanilla plant

Leuven. Climate change is changing the habitats of vanilla plants – and could thus impact global vanilla production in the long term. A team from the University of Leuven in Belgium and the University of Costa Rica reports in the journal "Frontiers in Plant Science" that increasing climate extremes are changing the habitats of wild vanilla species – previously mostly found in tropical regions of Central America – and their mostly animal pollinators.

For example, some regions could become more attractive for plants, but no longer offer suitable living conditions for the insects that pollinate them. These changes could lead to less overlap between the habitats of pollinators and pollinated animals in the future, resulting in less pollination.

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“Preserving the natural populations of these wild species and thus the great genetic diversity they represent is crucial to securing the future of vanilla,” the team writes in a statement.

Using models, the researchers analyzed the distribution areas of eleven neotropical vanilla species and seven observed bee species under two climate scenarios up to the year 2050 – a medium scenario with moderate climate protection and a scenario with more conflicts and less global climate protection.

While some species may even expand their potential habitats as a result of global warming, others face a decline of more than half. Models predict a decline in suitable habitats for all bee species—with particularly drastic consequences in the less climate protection scenario.

While Vanilla inodora, for example, only grows in cloud forests and low-lying regions with heavy rainfall, other species only occur in hot regions with long dry periods – and could therefore benefit.

"A decoupling of plants and their pollinators could endanger the survival of wild vanilla species," warns lead author Charlotte Watteyn. A particularly problematic issue is that these species are usually specialized on a few or even single pollinators. Substitution relationships are therefore hardly possible. For species that rely on a single bee species, habitat overlap could even shrink by 60 to 90 percent.

Wild vanilla plants are also important for agriculture: Commercially cultivated vanilla (Vanilla planifolia) has low genetic diversity, which makes it particularly vulnerable to disease, drought, and heat—and thus already a victim of global warming.

Global warming could therefore have a similar impact on vanilla ice cream, pudding and other desserts as it does today on many other foods: For example, poor harvests of coffee, chocolate and olive oil repeatedly lead to shortages – and thus higher prices.

As a limitation of their study, the authors cite that comprehensive information on pollination mechanisms was not available for all species studied.

The team calls for increased international cooperation and further research: the aim is to ensure the resilience of vanilla cultivation and thus the livelihoods of many smallholder farmers in tropical regions.

RND/dpa