Global population of mammals, birds, reptiles, amphibians and fish continue to shrink, according to a biannual report released by the World Wide Fund for Nature (WWF).
The Living Planet Report 2016 said there was a 58-percent overall decline in vertebrate population sizes from 1970 to 2012. This means that population abundance of mammals, birds, reptiles, amphibians and fish dropped by more than half in the last 40 years.
According to the WWF, the 21st century presents humanity with a dual challenge: to maintain nature and its services and to create an equitable home for people on a planet with limited resources.
It says protecting the environment alongside economic and social development requires a system change.
“We need to shift from short-term decision-making toward adopting a long-term, comprehensive, intergenerational vision. A fundamental part of this is reforming our food and energy systems,” the WWF said.
The report is a comprehensive study of trends in global biodiversity and the health of the planet.
By providing an overview of the state of the natural world, human impacts and potential solutions, it aims to support governments, communities, businesses and organizations to make informed decisions on using and protecting the planet’s resources.
Using the Living Planet Index (LPI), the WWF noted an average decline of 2 percent with no sign of slowing down.
“If this downward trend persists, species populations could decline on average by 67 percent by 2020, within only half a century,” the report said.
The LPI tells how species are faring by measuring trends in 14,152 monitored populations of 3,706 vertebrate species.
It reports how wildlife populations have changed in size—as opposed to the specific number of animals that have been lost or gained.
The report attributed the decline in species population to habitat loss and degradation, overexploitation, pollution, invasive alien species, disease and climate change.
Monitored are species population in terrestrial habitats, which include forests, savannahs, grasslands, deserts, cities and agriculture fields, covering a total of 4,658 populations of 1,678 species.
The report indicated a 38-percent decline in average population size, with an average annual decline of 1.1 percent.
Among the biggest threats are habitat loss and degradation, followed by overexploitation. This is because of the fact that majority of earth’s land area is now modified by humans.
In freshwater habitats, which include lakes, rivers and wetlands, a total of 3,324 populations of 881 freshwater species were monitored. During the same period, the reported noted an annual decline of 3.9 percent. Freshwater covers just 0.8 percent of the earth’s surface, but provides a habitat for almost 10 percent of the world’s known species.
Like in terrestrial habitats, the biggest threats are habitat loss and degradation through direct and indirection intervention, and overexploitation.
In marine habitats, which include oceans and seas, coral reefs, mangroves and fishing grounds, the WWF monitored 6,170 monitored populations of 1,353 marine species, including birds, mammals, reptiles and fish.
The report noted a 36-percent decline in average population size between 1970 and 2012, with an average annual decline of 1 percent. The biggest threats are overexploitation followed by habitat degradation and climate change.
The majority of fish populations that contribute most to global fish catch are either fully fished or overfished.
According to the report, due to the warming of their Arctic breeding grounds, red knot birds are becoming smaller with shorter bills, making it increasingly difficult for them to reach deeply buried molluscs. Meanwhile, African elephants are severely threatened by overexploitation mainly by poaching, habitat loss and fragmentation.
New data shows their numbers have fallen by around 111,000 since 2006, to a total of about 415,000 today.
On the other hand, a third of sharks, rays and skates are estimated to be threatened with extinction primarily because of overfishing.
River dolphins, like Irrawaddy dolphins, are declining rapidly due to unintentional overexploitation, such as entanglement in gill nets.
The WWF report said human activities are affecting the large-scale systems that maintain life on Earth. “Researchers suggest that we have already crossed four of the nine Planetary Boundaries—on climate change, biosphere integrity, land-use change and flows of phosphorus and nitrogen—taking us into dangerous, unknown territory.”
According to the report, the Ecological Footprint—which measures the use of goods and services generated by nature—indicates that we require the regenerative capacity of 1.6 Earths to support global consumption. “The increasing pressure on biodiversity, our significant Ecological Footprint and the violation of Planetary Boundaries impact both people and nature. And they are rooted in our current systems of production, consumption, finance and governance.”
According to WWF, food production is one of the primary causes of biodiversity loss through habitat degradation, overexploitation of species, particularly overfishing, pollution and soil loss.
“It is also a strong force pushing against most Planetary Boundaries. New models of both production and consumption is needed to form a sustainable, resilient food system that can absorb and recover quickly from shocks, while continuously providing food to many more people.”