An apocalypse threatens insects around the world, as legions of them succumb to a host of stresses from intensive agriculture to climate change. Even if you’re not a fan of scary critters, this should alarm you because insects perform vital ecological functions, including acting as powerful pollinators.
Indeed, three quarters of food crops and four out of five wild plants depend on bees, wasps, flies, butterflies, moths and beetles to reproduce. The question is what if most of these insects disappear from agricultural and natural habitats?
A team of scientists from the Julius-Maximilians University in Würzburg, Germany, set out to find out by exploring how climate change and intensive land use affect the diversity of pollinating insects at local and landscape scales in the German state of Bavaria.
Scientists examined more than 3,200 species of pollinators from 179 sites in various habitats, from forests to grasslands, croplands to urban areas. As bees, flies, beetles, butterflies and moths react differently to increasingly hot and dry conditions, pollinators tend to become more homogeneous in warmer climates at the expense of diversity, scientists report. .
“[A]In addition to the importance of floral resources and the negative effects of land use intensification, climatic conditions play an increasingly important role in maintaining pollinator diversity,” observes Prof. Ingolf Steffan -Dewenter, who works in the Department of Animal Science at the university. Ecology and tropical biology.
“For example, the combination of high temperatures and low rainfall negatively affected total pollinator diversity, while bee richness in urban areas was negatively affected by higher average temperatures,” adds the scientist.
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global insect refuges
However, it’s important to note that in landscapes that have higher proportions of forested area, more diverse pollinator communities may continue to thrive, as forests “can buffer the effects of global warming to some extent,” according to the words of Cristina Ganuza. , a doctoral student at the university who was a key member of the research team.
“We concluded that much of the forest land in the landscape could serve as a refuge for insects from global warming. This is likely because forests and forest edges provide largely natural conditions that buffer extreme heat and drought compared to more human-influenced habitats,” says Ganuza.
For ecosystems to function properly, a high diversity of pollinators is needed, as various plant species depend on various pollinators. “However, the combination of ongoing climate change and current land use will only allow certain pollinator species to survive in different types of habitats,” Ganuza warns.
In urban landscapes where temperatures are particularly high, partly due to the heat island effect, greening larger areas can ensure that insects find a safe haven in cities. “This could allow more species of bees to live in urban areas,” explains the biologist.
By Daniel T. Cross. Articles in English