Study Says Earth Has Lost Half of All Wildlife in the Last 40 Years

According to the results of a new study undertaken by WWF and ZSL, it is estimated that the total number of fish, birds, mammals, reptiles and amphibians fell by an astonishing 52 per cent between 1970 and 2010. To reiterate that’s 52% of wildlife lost in the last 40 years.

The obvious question to ask is what caused such a massive decline? It may not surprise you that the main culprits are humans. Through hunting, fishing, deforestation, pollution and other types of habitat destruction we have contributed a major part to this loss of wildlife.

We want to emphasise this does not mean we have wiped out half of all species on the planet. What it means is that on average, the population of the world’s vertebrate species is about half the size it was in 1970 according to the study.

How did the researchers arrive at this number? Scientists from the WWF and ZSL compiled their “Living Planet Index” by studying 10,380 representative populations from 3,038 species of fish, amphibians, reptiles, birds and mammals from all over the world. They then looked at how the trends have evolved over time.

Animal Numbers Are Falling

• The populations of land animals including tigers, gorillas, elephants have fallen by 38 per cent since 1970.
  The big problem here is of course habitat loss and poaching. For example deforestation in Central and West Africa has meant that forest elephants have been left with small islands of disconnected habitats and as a result they are easy targets for ivory poachers. Unsurprisingly their numbers have fallen by a whopping 60 per cent since 2002.
• Marine species such as seabirds, fish, sharks and turtles have seen their global populations fall by 39 per cent.
  The picture however is more mixed, with some populations such as the California Blue Whale staging a recovery from over fishing. Other species have not been so lucky, there are large numbers of seabirds, sharks and turtles that are accidentally trapped and killed by fisherman who are seeking other species in a practice known as “bycatch”

Freshwater Populations Have Fallen by as Much as 76%

• Freshwater populations such as shorebirds, frogs and fish, which have seen their populations drop by 76%.
  This makes them the worst affected category in the study. The main drivers here are water pollution and habitat loss, as well as changes in water levels as a result of human activity. For example in South Australia, humans have been taking fresh water for irrigation purposes from the Coorong Wetland. This has meant the water has become increasingly saline causing declines in shorebird and fish populations.

In the report, was a compilation of “primary” threats to animal populations that are most at risk. The biggest threats to wildlife species as we mentioned before were habitat loss and “exploitation” which includes hunting and fishing. A much smaller threat over the last 40 years has been global warming though the researchers warn that this could evolve into a far bigger threat in the future.

Populations in Protected Areas Falling At a Much Slower Rate

The report was not all boom doom and gloom. The researchers found that land based species inside protected areas were doing slightly better with their populations falling by 18 per cent since 1970. This compares with the 39 per cent decline for species that are located outside protected areas.

Whilst that doesn’t sound great on the face of things, the authors of the report say it is encouraging. The researchers go on to add that the figures are not supposed to be taken as solid evidence that wildlife protection and conservation efforts are working. This could be because species located inside areas that are protected are simply less vulnerable to the myriad of pressures that other wildlife face.

The Ugly Truth

The conservation picture looks more mixed when the researchers examine individual species. One particular bright spot is the Nepalese tiger population which is rebounding following a government crackdown on poaching in the country. Despite that bright spot, the overall trend is down. The ugly truth is that whilst the population of human continues to explode to over 7 billion, many species have seen their numbers fall to worrying levels.

• 18,000 lions
• 3,000 tigers
• 200,000 leopards
• 15,000 jaguars
• 70,000 bald eagles
• 400,000 elephants
• 700 gorillas
• 28,000 rhinos

Mountain Gorilla Populations Have Started To Recover

The report takes note of the fact that threats to animal populations are not mitigated by the designation of protected areas alone. Whilst there is plenty of causes for concern in the report, there are also some very notable conservation success stories. The mountain gorilla in Africa for example has seen their numbers recovering sharply in the Democratic Republic of Congo, Uganda and Rwanda largely as a result of a robust new gorilla tourism industry.

Humans Are Consuming Resources at an Unsustainable Pace

The report goes on to add that humans are consuming more of the Earth’s resources than the planet is able to sustainably accommodate and this means human beings are exhausting the ecological goods of one-and-a-half Earths.

People who live in high income countries have a much bigger ecological footprint compared to people living in low income countries the report said. However higher income countries have not suffered the largest losses to their ecosystems. In fact the report suggests that these countries show a 10 per cent increase in biodiversity whilst middle income countries saw an 18 per cent decline and low income countries experienced declines of as much as 58 per cent. In Latin America, species populations dropped by an astonishing 83 per cent between 1970 to 2010 making it the worst performing region in the world.

“We’re gradually destroying our planet’s ability to support our way of life,” Carter Roberts, president and CEO of WWF, said in a statement. “But we already have the knowledge and tools to avoid the worst predictions. We all live on a finite planet and it’s time we started acting within those limits.”