2023-09-14 01:20:30
About 90% of the world’s flowering plants depend on animal pollination to reproduce. Additionally, these plants form the basis of many food chains. In the case of the bumblebee (Bombus), this genus of hymenoptera is especially important for the pollination of crops in cold and temperate regions of the northern hemisphere. However, a study published in Nature assures that its pollination work is threatened by high temperatures and the increase in extreme weather events. These insects are especially sensitive to these factors, since they can reduce their fertility and even alter their cognitive abilities.
According to the authors of this research, preventing their decline, whether of arctic, alpine or other origins, involves directly addressing the known causes of their disappearance.
“These causes are multiple and include the degradation of their natural habitats, due to urbanization, landscape transformation for intensive agriculture and soil pollution. They are also affected by climate change and its various facets, such as heat waves, droughts and other extreme weather events, as well as the extensive use of herbicides, fungicides and insecticides, Inter alia”. declares to SINC Guillaume Ghisbainco-lead author of the study and researcher at the Free University of Brussels and the University of Mons
Therefore, he adds, “developing a comprehensive and large-scale understanding of their decline is essential to hope for halting the decline of their populations.”
Ghisbain’s team quantified the past, present and future habitats of Europe for these bumblebees. To do this, he compiled observational data from 1901 to 1970, from 2000 to 2014 and projections until 2080.
Their results suggest that around 38% to 76% of European bumblebee species currently considered non-threatened will see their range shrink by at least 30%, from 2061 to 2080. In particular, species from arctic and alpine environments may be on the verge of extinction in Europe. Scientists estimate that at least 90% of its territory will be lost in the same period.
Scandinavia, a possible escape
In this scenario, experts consider that Denmark, Norway and Sweden They could potentially become a refuge for displaced species.
According to the researcher, “bumblebees are organisms generally adapted to temperate or cold climates. This adaptation dates back to their evolutionary history, tens of millions of years ago, when they appeared during a period of pronounced cooling in the northern hemisphere. Even today, these animals are mainly found in regions with colder climates.”
He adds that the models they have developed “indicate that the ecological conditions of certain areas of Scandinavia – a region of Europe that is climatically and ecologically particularly favorable for bumblebees – could remain suitable for many species in the future.”
However, the authors also point out a drawback to this option. For this region to effectively support a diverse community of bumblebees in the future, it will be essential to ensure that it is free of decline factors that have not been included in their models: heat waves, droughts, the extensive use of pesticides, among others. .
Another important risk is that if many species converge in the same area, they could geographically concentrate their parasites, which could affect their communities. Finally, there are no guarantees that bumblebees will be able to migrate to this region from lower latitudes.
It is urgent to protect their natural habitats
For researchers, all the efforts that society makes to reduce our climate footprint They will be beneficial for the survival of these populations in the medium and long term. Furthermore, it is essential to ensure that their current habitats do not continue to undergo landscape transformation.
But it is not the only measure that must be taken, since the causes of the decline are “multifactorial,” according to the researchers. Among others, they highlight the need to reduce greenhouse gas emissions, especially carbon dioxide, methane and nitrous oxide, to limit the increase in global temperature.
On the other hand, public awareness and consumption patterns should be oriented towards the purchase of foods produced with environmentally friendly methods that benefit both ecosystems and human beings.
Impact on agricultural production
One of the sectors that will see its activity most affected is, precisely, agricultural sector, with obvious consequences for human nutrition and the economy. “In natural ecosystems, the problem is that some flowering plants are pollinated by very few insect species. If these disappear, the wild plants themselves could suffer a sharp decline,” the scientist emphasizes.
This portends an important impact also on herbivores and, later, on the carnivores that consume them. In short, if pollinators decline, there will be cascading consequences.
“At a time when a substantial portion of the land is dedicated to agriculture, they should reevaluate global policies to reconsider our approach to land use, placing the conservation of pollinator diversity on the same level as the preservation of other resources. “Governments should promote policies that strengthen regulations on pesticides to address landscape pollution,” says the expert.
Bumblebees vs domesticated bees
This study cannot be easily extrapolated to honey bees because they are very different from bumblebees, both in their ecology and in their physiology. “For example, bumblebees tend to be more specialized in their foraging habits than honey bees; They need specific plants to maintain their communities,” explains Ghisbain.
Plants in the Fabaceae family, for example, are crucial for many species of bumblebees, and without them, populations of certain species decline or disappear.
In the case of honey bees, however, their diet is more generalist, meaning that they can consume and use pollen and nectar from a much wider range of floral species. Furthermore, its reproduction is controlled by man. “This allows us to relocate a hive with thousands of individuals to a specific location, a practice that is impossible for the vast majority of bee species,” he notes.
However, a common factor between honey bees and bumblebees is that a high quality natural environmentabundant in different species of wildflowers, with minimal or no use of pesticides and limited urbanization, is very beneficial for the health of its populations.
Similarly, both domestic bees and bumblebees are affected if droughts or heat waves They cause mass death of the flowering plants from which they obtain their resources. “Therefore, taking care of the climate and ecosystems will have very positive effects for both wild and domesticated bees,” emphasizes the scientist.
The particular case of the Iberian Peninsula
At European level, there are more than 2,100 species of wild bees, that is, they are not domesticated like the honey bee (Apis mellifera). Likewise, Spain is the second country in Europe with greater diversity of species of wild bees, only behind Greece.
“Every year, new species of bees unknown to science are discovered in Spain, which makes this country a true treasure of biodiversity. But bumblebees are not very diverse in most of the Peninsula, due to the hot and dry climate of many regions,” says Ghisbain.
To observe rich bee communities in Spain, you have to go to the Cantabrian mountain range and the Pyrenees. However, some bumblebee species are already experiencing decline in these regions. “It is absolutely essential to preserve these sanctuaries of diversity, avoiding anthropogenic stressors”concludes the expert.
References Guillaume Ghisbain et al. Projected decline in European bumblebee populations in the twenty-first century. Nature.
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