2 drivers of mass extinction of insect populations finally identified

(ORDO NEWS) — They help us bring food to the table through pollination and nutrient recycling. They decompose and utilize organic waste and are food for many animals.

As the famous ecologist E.O. Wilson, “Insects are little creatures that run the world.” At least 87 major crops of mankind depend on them, but it is becoming increasingly difficult for insects to survive on our planet. Now a new study has revealed how human-made disturbances interact to worsen many insects, from beetles to flies.

Among the problems we have caused are the clearing of vast swaths of their natural habitat, the introduction of toxic chemicals into their environment, and rising temperatures that have led to widespread declines or changes in species numbers.

Using data on insect populations and biodiversity in more than 6,000 different locations around the world, environmentalist Charlie Outwaite and his colleagues at University College London tracked how changes in insect abundance and biodiversity changed over 20 years depending on two factors: the intensity of agriculture and climate warming.

They found that the greatest declines in insect populations and species richness occurred in areas of intensive agricultural use, which have also seen significant increases in warming over the past 20 years.

However, where there was plenty of natural habitat, insect declines in the vicinity decreased dramatically. In areas where three-quarters of the natural habitat remained, the number of insects decreased by only 7 percent on average, and the number of different species by only 5 percent, compared with 63 and 61 percent in areas where less than a quarter of the natural habitat remained.

“Careful management of agricultural areas, such as preserving natural habitats near farmlands, can help ensure the continued prosperity of vital insects,” explains ecologist Tim Newbold, also from University College London.

This includes reducing the intensity of farming by diversifying the types of crops grown in one area (moving away from monoculture farming) and using less pesticides and fertilizers.

All of these activities provide insects with safer places to hide during sweltering weather, as well as providing them with enough food and other resources to continue doing the work we all depend on.

All of us can also help by choosing low impact foods and growing a variety of native plants wherever possible.

The researchers found that the tropics and the Mediterranean were hardest hit, where the combination of habitat disturbance and rising temperatures proved too much for many species. For example, the number of orchid bees in Brazil has declined by about 50 percent.

However, in temperate areas, biodiversity is on the rise due to warming, and not all species fare worse: other studies have found a widespread increase in freshwater insects.

“Many of these positive trends have been noted in non-tropical regions such as the UK and Europe, where much has been done in recent years, for example, to improve water quality in rivers after water quality has deteriorated in the past,” Newbold and Outwait explain.

With about 5.5 million species, insects make up about half of all known living things on Earth. This is a huge chunk of all life in the universe known to us, and we still do not fully understand to what extent we messed everything up.

Our findings highlight the urgency of action to preserve natural habitats, slow the expansion of high-intensity agriculture, and reduce emissions to mitigate climate change,” Oatwaite says.

The combined impact of climate change and biodiversity loss, which are two sides of the same coin, “means that the health, well-being and livelihoods of many people in the tropics and beyond hang in the balance,” the researchers conclude.

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