The near-total disappearance of bats has forced farmers in New England (USA) to use 30% more insecticides to contain the pests in their crops. At the same time, infant mortality due to disease and difficult childbirth in the same regions has increased by 8%, according to a recent study published in ScienceThe authors link the increase in deaths to the increased use of chemicals proven to be harmful to fetuses and children.
This is the latest example, among many others, where the destruction of nature is turning against human beings. Perhaps one of the most surprising – “my jaw has dislodged” analyses one of the experts consulted by Science– but not the only one.
Although UN scientists warn that up to a million wild species are “at risk of extinction,” the warning goes unheeded. Some scientists are quick to call it the sixth mass extinction. But that low profile suddenly disappears when a virus that has been trapped in an animal jumps to humans because intensive deforestation has brought the two species into contact, or when fishermen haul out their nets empty because the fish are gone.
Endangered trees and human diseases
More than half of the Amazon’s approximately 15,000 tree species are threatened by rainforest deforestation. In danger of disappearing by mid-century if the rate of destruction is not corrected. The latest global assessments of forest loss indicate that after some progress, “we are falling behind.”
With the disappearance of millions of trees in the Amazon, tropical Africa and Indonesia, the habitats where many animals live retain countless pathogens ready to infect humans. Scientists estimate that more than 1.5 million viruses are contained in wild animals. “They represent 99.9% of potential zoonoses” (diseases of animal origin), calculated the first attempt to map these pathogens. A kind of “Pandora’s box” that is opening more and more as vast areas of forest are destroyed.
Because without these habitats, contact between humans and wild species (with their incorporated viruses) increases. Disease transmission to humans is increasingly common: 75% of new diseases that have appeared in humans over the past 40 years originated in animals. Covid-19 is the latest extreme case. But so did SARS in 2002, influenza A in 2009, and MERS in 2012.
Food hazard
Bats of the United States, stars of the book presented in September at Science They have been dying en masse since 2006 due to infection by an invasive fungus. Pseudogymnoascus destructans It arrived in caves in North America, probably introduced from Europe. Invasive species are one of the main causes of biodiversity loss in the world. This loss actually means the disappearance of specific specimens and species.
And among the groups hardest hit by this mass extinction are insects. The confirmed collapse of bee and butterfly populations has been described as a “threat of nature’s collapse”. Intensive agriculture – due to the massive application of pesticides – the destruction of the ecosystems in which they live and climate change have decimated species, especially the most common ones.
In Spain, there are only about 66 types of insects in the catalogue of species under special protection, plus another 36 classified as vulnerable or in danger of extinction. Very few have a popular name like the Iberian sulphur butterfly or the girl of the Sierra Nevada. The National Pollinator Conservation Strategy explains that it is difficult to know the degree of alteration and predict its functional consequences. However, the government document admits: “While the global primary production system is threatened, the seriousness of the problem goes beyond the irreversible loss of species.”
The lack of insects already causes direct and increasingly measurable damage to humans: between two and three thirds of the world’s farms produce less due to the lack of pollinators. This is not a reality foreign to Spain since crops that necessarily require insects for flowers to turn into fruit are a strength of Spanish agriculture. In terms of food production alone, pollinators contribute a value of 2.4 billion euros per year to Spanish agriculture.
Spain – the second largest consumer of insecticides in the EU after Germany – is an energy exporter of fruits and vegetables (plants that require pollination). It represents 28% of European stone fruit production; it is, among other things, the world’s second largest producer of almonds and the world’s largest exporter of fresh citrus fruits, according to the archives of the Ministry of Agriculture and Fisheries.
An example of this relationship can be traced in the boom of avocados in Spain. This crop has presented problems of pollination (main reduction of the production). An avocado tree can have millions of flowers, but only 0.15% bear fruit because the pollen does not reach the stigmas. A team from CSIC concluded by studying the phenomenon that “an increase in the number of pollinators will encourage a good quantity of pollen grains to reach the flower and will favor the production of fruit”. And this will have as a consequence, they described, that “the quantity of liters of water consumed by the tree per kilo of fruit produced would be reduced”. From this point of view, insects can save water in a country facing recurrent water crises.
Destroying seagrass is suicide
In Spain there are about 1,100 km2 of Posidonia meadows. Destroying these seagrasses – which only grow in the Mediterranean – is a kind of suicide because not only do they protect the coasts from marine attacks or retain an exorbitant amount of carbon accumulated over the centuries (which would reinforce the greenhouse effect in the atmosphere), but they also play an important role in fishing and tourism.
Posidonia meadows have disappeared over the last half-century at a rate of between 13 and 38% in the colonies of the western Mediterranean and 50% in the rest of the marine basin.
Oceanic Posidonia “This is a resource that generates quantifiable economic benefits,” states the final document of the Conservation of Life in the Andalusian Mediterranean project. More than 200 million euros per year between ecosystem services, fishing and especially tourism (around 124 million euros have been estimated in this sector alone).
A similar valuation for the posidonia colonies of the Balearic Islands (where 50% of these meadows in Spain are located) added another 600 million, not including fish production.
“These are essential elements for the conservation of the Spanish Mediterranean marine environment,” explains the Ministry of Ecological Transition, which at the same time recognizes that they have suffered “a significant regression of the waters of the Spanish coast and, in the case of some populations, are seriously threatened.
