“IF ALL MANKIND WERE TO DISAPPEAR, THE WORLD WOULD REGENERATE BACK TO THE RICH STATE OF EQUILIBRIUM THAT EXISTED TEN THOUSAND YEARS AGO. IF INSECTS WERE TO VANISH, THE ENVIRONMENT WOULD COLLAPSE INTO CHAOS.”
Edward O. Wilson, biologist
What are the causes of this apocalyptic threat?
They are many, complex, and interrelated, and humans are at the center of the problem.
Today we are aware of the harmful effects of pesticides, and some have been banned – for example, the European Union has banned the use of various neonicotinoid insecticides that are clearly toxic to pollinators. However, the EU’s current risk assessment system is based on the mortality of adult bees.
This is insufficient because it does not account for pesticides’ “sublethal” effects: The permitted doses of these chemicals cause bees to become disoriented and compromise their immune and reproductive systems; they effect successive generations of bees because larvae may be fed with contaminated pollen (even long after the chemicals are spread), which leads to incomplete and improper development and, eventually, the failure of the colony; and their effects on other wild pollinators are not measured.Pesticides, fungicides, and herbicides persist in the soil for a long time and can contaminate water and flowers for years after being used.
The climate crises, driven by rising temperatures and CO2 concentrations in the atmosphere, is altering the life cycles of plants: Droughts, violent weather events, and sudden frosts or heat waves compromise plants’ ability to supply nectar and pollen, and when blossoms appear too early or too late, pollinators cannot perform their services or gather the food they need.According to an article in Science entitled “” with the current forecast of a 3.2°C increase in average global temperature by the year 2100, it is expected that 49% of insect species, 44% of plant species, and 26% of vertebrate species will see their geographic ranges decrease by over 50%.A temperature increase of 2°C would lead to a range reduction of at least 50% for 18% of insects, 16% of plants, and 8 % of vertebrates, and for a 1.5°C increase, these numbers would fall to 6% of insects, 8% of plants, and 4% of vertebrates.
Widespread bee death and biodiversity loss are locked together in a vicious cycle: Each is both a cause and a consequence of the other. The growing expanses of agricultural monocultures all over the world are food deserts for pollinators and do not offer the habitats that these insects need for nesting and reproduction, thereby weakening their populations and making it difficult for them to adapt.
Another threat to bees is the degradation of soil, a fundamental natural resource at the basis of the ecosystem services that provide for and regulate life on Earth. It takes 500 years for a 2.5-centimeter layer of fertile soil to form under normal conditions, but today phenomena such as erosion, contamination, salinization, and compaction – all caused or exacerbated, directly or indirectly, by human activity – make soil arid and sterile, damaging the ecosystems of which bees and other insects are a part. And this is without even mentioning the rapidly growing areas of land under cement and other kinds of pavement.
In this context, pollinators are becoming increasingly vulnerable and are unable to adapt to the sudden changes that humans are causing in the environments where they live. Globalization has facilitated the rise and spread of ever more aggressive diseases and parasites, which can weaken and kill entire bee colonies.Beekeepers are constantly engaged with monitoring, prevention, and containment measures, but wild bees have no protection.
Natural habitats must be restored and agriculture redesigned. Agroecological practices favor not only pollinators, but also the natural enemies of parasites, thus allowing the agroecosystem to keep itself in balance. It is important to plant crops in alternating strips, to include hedges and mixed species meadows, and to rotate crops with clover and other legumes.
It is also essential to minimize the use of pesticides, especially insecticides and fungicides, in order to allow insect populations to recover and to continue to carry out their beneficial work in the ecosystems that we share with them.