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Insects, extinction and biodiversity

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This issue of The River Reporter features several stories on insects—some wanted, like bees, others unwanted, such as emerald ash borers, ticks and spotted lanternflies, all of which have populations that are growing in the Northeast. Globally, however, insects are under threat as their populations decline.

That may seem like good news for people tired of swatting away pesky flies or watching them eat holes through their gardens—but it’s actually quite a bad outlook for the health of our planet.

A 2018 study published in the Proceedings of the National Academy of Science in the United States of America (www.pnas.org/content/115/44/E10397) looked at the insect population of a specific forest in Puerto Rico. 

Here’s part of what the authors wrote: “We compared arthropod [insect] biomass in Puerto Rico’s Luquillo rainforest with data taken during the 1970s and found that biomass had fallen 10 to 60 times. Our analyses revealed synchronous declines in the lizards, frogs, and birds that eat arthropods. Over the past 30 years, forest temperatures have risen 2.0 °C, and our study indicates that climate warming is the driving force behind the collapse of the forest’s food web. If supported by further research, the impact of climate change on tropical ecosystems may be much greater than currently anticipated.”

Another study, this one from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) looked at the impact of human activity on all animal species.  The study estimated that there are 8.1 million species of animals and plants on the planet and 1.7 million have been identified. Insects make up about 75% of species, or about 6 million species.  The study estimates that one million species are threatened with extinction because of human activity and global climate change, and about 600,000 of those are insects.

The impact, of course, is already being felt by numerous plants and animals. “The average abundance of native species in most major land-based habitats has fallen by at least 20%, mostly since 1900. More than 40% of amphibian species, almost 33% of reef-forming corals and more than a third of all marine mammals are threatened. The picture is less clear for insect species, but available evidence supports a tentative estimate of 10% being threatened. At least 680 vertebrate species had been driven to extinction since the 16th century and more than 9% of all domesticated breeds of mammals used for food and agriculture had become extinct by 2016, with at least 1,000 more breeds still threatened.”

The report names five reasons for the loss of biodiversity it chronicles. In order of importance they are: changes in the human use of land and sea; the human exploitation of plants and animals; climate change; pollution; invasive species.

Since the executive summary of the report was on May 6, hundreds of articles have appeared in publications around the world citing it as a wake-up call to the planet for citizens to begin to rethink the consumption society that has brought us to this point. 

Robert Watson, the immediate past chair of IBPES, testified at a public hearing of the House Committee on Natural Resources on May 22, and said, “The evidence is unequivocal: biodiversity, which is important in its own right and essential for human well-being, is being destroyed by human activities at a rate unprecedented in human history.”

Others, including Patrick Moore, one of the co-founders of Green Peace, called the study bunk. “As with the manufactured ‘climate crisis,’ they are using the specter of mass extinction as a fear tactic to scare the public into compliance,” Moore, who advocated pulling out of the Paris Climate Agreement, said. “The IPBES itself is an existential threat to sensible policy on biodiversity conservation.”

 At the same hearing, Republican Rep. Tom McClintock, blasted the report as just the latest “apocalyptic prediction.” He noted a previous claim from 1970 by a Smithsonian official that up to 80% of animals would be extinct within 25 years.

Whether one million species of plants and animals are actually at risk is really beside the point. When one considers the way that humans are using the resources of the planet, one must conclude that the impacts are immense.

Per the report: “Three-quarters of the land-based environment and about 66% of the marine environment have been significantly altered by human actions. More than a third of the world’s land surface and nearly 75% of freshwater resources are now devoted to crop or livestock production.  In 2015, 33% of marine fish stocks were being harvested at unsustainable levels; 60% were maximally sustainably fished, with just 7% harvested at levels lower than what can be sustainably fished.”

Plus, we’re dumping tons of plastic into the ocean on a daily basis, and pumping CO2 and methane into the atmosphere with abandon. If a majority of us don’t soon come to recognize that the actions of eight million modern humans have had an enormous impact on the planet, there will not be sufficient time or willpower to address the issue.

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