Sharp Decline Threatens Ecosystem
Insects around the world are in a crisis, and a new study published in the Proceedings of the National Academy of Sciences suggests that the problem is even more widespread than scientists first believed. In a pristine rain forest in Puerto Rico, the number of invertebrates—including moths, butterflies, spiders and grasshoppers—dropped 60-fold between 1977 and 2013, probably due to a four-degree rise in average temperature. The lizards, birds and frogs that fed on them also seriously declined. In 2014, an international team of biologists estimated that globally in the past 35 years, the numbers of invertebrates such as beetles and bees had decreased by 45 percent.
Another recent study showed a 76 percent decrease in flying insects in the past few decades in German nature preserves. The food web may be being obliterated from the bottom: Insects pollinate three-quarters of our food crops, feed the birds and fish that are also consumed by larger species and are vital to the decomposition that keeps soil healthy and ecosystems running. “Nature’s resilient, but we’re pushing her to such extremes that eventually it will cause a collapse of the system,” Brad Lister, a co-author of the Puerto Rican study, told the New York Times.