Global wildlife populations have decreased by more than half since 1970, and will likely fall by two-thirds that number in some instances before the end of the decade, according to a new report released earlier this week by the WWF and the the Zoological Society of London (ZSL).
According to BBC News and New Scientist, the groups’ Living Planet Index assessment found that overall populations of wildlife have fallen 58% over the past 46 years, and that most of those losses have involved species living in lakes, rivers, and wetlands. The primary causes, the WWF and ZSL said, are habitat loss, wildlife trade, pollution, and man-made climate change.
The assessment measured population numbers of 14,152 populations of 3,706 species of birds, fish, reptiles, amphibians and mammals from all over the world, the media outlets reported. The results show an average decrease in population numbers of 2% per year. Furthermore, by 2020, as much as 67% of the vertebrate species populations may wind up being wiped out in a “mass extinction” event unless the damage caused by human activity is reversed, they added.
“For the first time since the demise of the dinosaurs 65 million years ago, we face a global mass extinction of wildlife,” Mike Barrett, WWF-UK’s science and policy director, said Thursday in a statement. “We ignore the decline of other species at our peril – for they are the barometer that reveals our impact on the world that sustains us.”
“Humanity’s misuse of natural resources is threatening habitats, pushing irreplaceable species to the brink and threatening the stability of our climate,” he added. “We know how to stop this. It requires governments, businesses and citizens to rethink how we produce, consume, measure success and value the natural environment. In the UK, this demands a serious plan to strengthen protection for habitats and species and new measures to fast track low-carbon growth.”
Study’s findings called into question by some experts
The report warned that unsustainable fishing and agriculture are increasingly affecting species, and as New Scientists reported, mining, pollution and climate change are also factors which are leading to the demise en masse of creatures such as African elephants in Tanzania (which have been victims of poaching) and Brazil’s maned (which are losing habitat to farming).
Humans are also being victimized by their own activities, the report said, due to the increasing losses of plants needed for breathable air, as well as sources of drinkable water and food. Some of the news is good, however, as the study found a slight increase in grassland species over the last 12 years, which is being attributed to conservation efforts for some African mammals.
Terrestrial species have seen a population decrease of 40% since 1970, the study found. Avian populations are also on the decline, but freshwater species have seen an 80% decline during the last four-plus decades. Wetland wildlife species have seen an increase in numbers since 2005, New Scientist said, while marine species have reportedly stabilized since 1988.
“Human behavior continues to drive the decline of wildlife populations globally, with particular impact on freshwater habitats,” ZSL science director Professor Ken Norris said in a press release Thursday. “Importantly, however, these are declines – they are not yet extinctions,” he said, “and this should be a wake-up call to marshal efforts to promote the recovery of these populations.”
However, BBC News pointed out that the study had drawn criticism from some experts in the field, including Duke University conservation ecologist Stuart Pimm, who said that while some of the data was “sensible,” some of the numbers cited by the report were “very, very sketchy… They’re trying to pull this stuff in a blender and spew out a single number… It’s flawed.”
“If you look at where the data comes from… it is massively skewed towards western Europe,” Pimm told the British news outlet. “When you go elsewhere, not only do the data become far fewer, but in practice they become much, much sketchier… there is almost nothing from South America, from tropical Africa, there is not much from the tropics, period. Any time you are trying to mix stuff like that, it is is very very hard to know what the numbers mean.”
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