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Saturday, 31 January 2015

Here Comes the Sixth Mass Extinction : And This One is Man Made

Readers of this blog may have seen on the news last week, in one of those rare instances where the national tv news features ecological issues, that the Northern White Rhino (see above) is about to become extinct. Only five of then still exist and the one male and four females are all too old now to breed. So that is it, when they are gone they are gone forever, bar some huge scientific leap which enables their recreation from frozen sperm and egg samples.
Our planet is now in the midst of its sixth mass extinction of plants and animals, the sixth wave of extinctions in the past half-billion years. We’re currently experiencing the worst spate of species die-offs since the loss of the dinosaurs 65 million years ago. Although extinction is a natural phenomenon, it occurs at a natural “background” rate of about one to five species per year. Scientists estimate we’re now losing species at 1,000 to 10,000 times the background rate, with literally dozens going extinct every day . It could be a scary future indeed, with as many as 30 to 50 percent of all species possibly heading toward extinction by mid-century.  Unlike past mass extinctions, caused by events like asteroid strikes, volcanic eruptions, and natural climate shifts, the current crisis is almost entirely caused by humans. In fact, 99 percent of currently threatened species are at risk from human activities, primarily those driving habitat loss, introduction of exotic species, and global warming . Because the rate of change in our biosphere is increasing, and because every species’ extinction potentially leads to the extinction of others bound to that species in a complex ecological web, numbers of extinctions are likely to snowball in the coming decades as ecosystems unravel.
The latest edition of Green World, the Green Party's official magazine, contains a very good article on the extent of the problem entitled, "Protecting Biodiversity":


The answer is a broad range from amphibians and insects to birds and primates. The new 'Living Planet' report from the WWF and the Zoological Society of London reveals that there has been a decline of 50% in the world's wildlife populations since 1970. In particular:
- A third or more of the 6,300 species of amphibians are in danger of extinction.
- Globally, BirdLife International estimates that 12 percent of known 9,865 bird species are now considered threatened, with 192 species, or 2 percent, facing  an “extremely high risk” of extinction in the wild, two more species than in 2008.
-Across the globe, 1,851 species of fish , 21 percent of all fish species evaluated, were deemed at risk of extinction by the IUCN (International Union for Conservation of Nature) in 2010, including more than a third of sharks and rays.
- About 90 percent of primates, the group that contains monkeys, lemurs, lorids, galagos, tarsiers, and apes (as well as humans), live in tropical forests, which are fast disappearing. The IUCN estimates that almost 50 percent of the world’s primate species are at risk of extinction. Overall, the IUCN estimates that half the globe’s 5,491 known mammals are declining in population and a fifth are clearly at risk of disappearing forever with no less than 1,131 mammals across the globe classified as endangered, threatened, or vulnerable.
- Invertebrates, from butterflies to mollusks to earthworms to corals, are vastly diverse and though no one knows just how many invertebrate species exist, they’re estimated to account for about 97 percent of the total species of animals on Earth . Of the 1.3 million known invertebrate species, the IUCN has evaluated about 9,526 species, with about 30 percent of the species evaluated at risk of extinction.


On Wednesday 22 May 2013 The State of Nature report was launched by Sir David Attenborough and UK conservation charities at the Natural History Museum in London while simultaneous events were held in Edinburgh, Cardiff and Belfast. Unfortunately this did not receive any way near the media attention it deserved. Scientists working side-by-side from 25 wildlife organisations compiled a stock take of our native species, the first of its kind in the UK. The State of Nature report reveals that 60% of the species studied have declined over recent decades. More than one in ten of all the species assessed are under threat of disappearing from our shores altogether.
Sir David Attenborough said at the time:

“Our islands have a rich diversity of habitats which support some truly amazing plants and animals. We should all be proud of the beauty we find on our own doorstep; from bluebells carpeting woodland floors and delicately patterned fritillary butterflies, to the graceful basking shark and the majestic golden eagle soaring over the Scottish mountains.This report shows that our species are in trouble, with many declining at a worrying rate. However, we have in this country a network of passionate conservation groups supported by millions of people who love wildlife."

You can read the State of Nature report here:


The short answer is human activity and human greed. Development and industrialisation leads to habitat loss and habitat fragmentation. Fragmentation of habitat makes it impossible for species to breed as small areas of woodland and water are not enough as gene pools are limited. Pollution is of course an ongoing problem with amphibians particularly vulnerable as amphibian skin is sensitive to contaminants.
Intensive farming methods is a massive cause of bird decline in the UK as powerful insecticides kill the insects which birds rely on for protein to feed their chicks, particularly the insect grubs. Hunting of course explains the decline in elephants and rhinos, which are killed for their horns and tusks. Capitalism can perversely raise the price of these horns/tusks as each animal shot reduces the numbers and increases the rarity.
Add to the above the effects of global warming, logging, the introduction of invasive species, road building and over-fishing and you get the idea.

Therefore unless we act now, both in the UK and globally, the 21st Century will be the century when much of the wildlife which we often take for granted will vanish from the planet.

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