Fri. Aug 23rd, 2019

Agricultural practices lead insects to a massive disappearance | Society

Agricultural practices lead insects to a massive disappearance | Society



Insects are threatened around the world and their disappearance can cause a "catastrophic collapse" in natural ecosystems, according to research from the University of Sydney (Australia) published in the scientific journal Biological Conservation. Their conclusions suggest that more than half of the species are decreasing rapidly and a third is threatened by extinction. Some data that make us fear that more than 40% of the species of insects are extinguished in the coming decades. Butterflies and moths are among the most affected.

The data are so worrisome that the authors of the research - Francisco Sánchez-Bayo and Kris A.G. Wyckhuys- interpret that since insects comprise about two-thirds of all terrestrial species, we are at the beginning of the "sixth mass extinction," which is "profoundly" affecting life on our planet. These animals are essential since they are food for others, in addition to being pollinators.

The research brings together first time the results of 73 partial studies carried out in different parts of the world, especially in developed countries of Europe and North America where the most complete historical records are found. The data conclude that the changes that are occurring in habitat and pollution are the main culprits of the downward trend of insects. And it points to the intensification of agriculture in the last six decades as the "fundamental cause of the problem to the use of synthetic pesticides." A behavior that is repeated throughout the world. For this reason, they conclude: "Unless we change our ways of producing food, insects as a whole are on the road to extinction in a few decades." The repercussions that this will have for "the ecosystems of the planet are, at least, catastrophic, since insects are in the structural and functional basis of many of them since their appearance at the end of the Devonian period, almost 400 million years ago" .

In 2017, a study of 27 years in several protected areas of Germany determined a "striking 76% decrease in the biomass of flying insects". These figures represent an average of 2.8% loss in insect biomass per year in areas with low levels of human disturbance. It is worrisome, the scientists warn, that the decline is constant over three decades. A more recent study in the tropical rainforests of Puerto Rico shows biomass losses of between 98% and 78% for arthropods.

Both studies are in line with previous reports on the decline of butterflies, beetles, ladybirds, dragonflies, stone flies and wild bees in Europe and North America in recent decades. It seems that the loss of insects is substantially greater than those that have suffered birds or plants during the same periods, which could "trigger cascading effects within the world's ecosystems".

Some of the improvements that are proposed to alleviate the situation are to increase the strips of flower hedges on the edges of the field that increase the abundance of wild pollinators and the rotation of crops that enhance the presence of bumblebees. This "ecological engineering" also conserves the natural insects "that are essential to keep the pests of many crops at bay", they specify. For aquatic insects, the aim is "the rehabilitation of the marshes and the improvement of water quality".

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