Wildlife Populations In World Are In Steep Decline Mainly From Loss Of Natural Habitat

The Living Planet Index (LPI) tracks almost 21,000 populations of vertebrates around the globe: mammals, birds, fish, reptiles and amphibians. From 1970 to 2016 there has been a decline of sixty-eight percent of the abundance of living vertebrate species on Earth. (1) That is an astounding loss two-thirds of the total volume of wild animals on the planet in less than 50 years.  

“We are eroding the very foundation of our economies, livelihoods, food security, health and quality of life worldwide,” announced Sir Robert Watson, Chair of the UN Intergovernmental Science Policy Platform on Biodiversity and Ecosystem Services (IPBES), in its April of 2019 report.

On Earth there are an estimated 8 million plant and animal species, including 5.5 million insect species. About one million of these remaining plant and animal species are threatened with extinction, many within only a few decades. 

The main cause of the loss of wild animal extinction on the land and in the oceans is loss of their natural habitat from human impacts.  A large driver of loss of natural habitat on land is from the conversion of natural areas, such as forests, savannahs, grasslands and wetlands for grazing of cattle and farming, including the clearing of vast forests for monocultural plantations of soybeans and palm oil.  

Seventy percent of the world’s plants and animals live in forests, the greatest number, fifty percent, in tropical forests.,

All regions of the Earth have witnessed a sharp decline of species but the areas with the highest rates of decline, especially of birds and mammals, are the warmest regions between the Tropics of Cancer and Capricorn. 

There has been a precipitous decline of vertebrate species in areas of moist tropical rainforests that are adjacent to mountain regions such as the Andes that feed water to the Amazon region and the vast Pantanal wetlands south of the Amazon. Also fed by water from mountain ranges is the Congo basin that is adjacent to the eastern African highlands and the south Asian jungle belt below the Himalayas with both regions having suffered sharp declines of vertebrate species in recent decades.    

During the last 100 years, 200 species of vertebrates have gone extinct, a loss of 2 species a year.  The average extinction rate before the advent of humans, during the past 2 million years, has been much slower. It would have taken 20,000 years, not a mere100 years for 200 species to have gone extinct. 

Since the sixteenth century, 680 vertebrate species have gone extinct. 

Remarkably, one-third of all land vertebrae and 8,851 of 27,600 species are experiencing a sharp drop in populations and that may result in the loss of the entire species. 

A small sampling of endangered species around the world include the black rhino, occupying several regions of central and southern Africa, and is critically endangered. Only 5,600 remain. The Amur leopard, native to Russia and China, has a wild population of only 100 animals that survive – the major cause of their decline is deforestation.  The Sumatran orangutan, one of the five great primates along with the gorilla, chimpanzee , bonobo and human, survives on the Indonesian island of Sumatra. The orangutan population has has dwindled to only 14,000 and is critically endangered.  The Cross River gorilla occupies lowland forests and rainforests of Cameroon and Nigeria.  Only 200 to 300 of these gorillas have survived. An estimated 3,900 tigers remain in the wild, in Southeast Asia. The Amazon river dolphin, also known as the pink river dolphin, lives only in fresh water of the Amazon and Orinoco river basins of South America. Both its habitat and the dolphin are quickly disappearing. The Orinoco crocodile, the largest predator in the Americas, can weigh up to 1,000 lbs. and reach 19 feet in length. Their population has dwindled to 500 individuals. The giant otter of South America, the largest of the otter species, hunted for fur as well as its wetland habitat are disappearing with only 2,000 to 5,000 individuals that remain in the wild. Several groups of spider monkeys, including the long-haired spider monkey and red-faced spider monkey live in jungle habitat of Central and South America. Five species are listed as endangered and one as critically endangered, due to hunting and loss of their habitat.  Jaguars are able swimmers and climbers and once lived across many regions of South America. Today less than half of their original population survive, mainly in the Amazon rain forest and the riverbanks of the Pantanal wetlands.  Macaws are the largest parrot consisting of 17 different species that survive in South America. Half are considered threatened or endangered, including the large, bright, blue hyacinth macaw, of which only 3,000 survive in the wild. 

Loss of biodiversity is the decline of species diversity or richness. It is the reduction of the number of species and is an important marker in the loss of wildlife but is different than the volume of the abundance of wild animals on the planet, that has seen a dramatic two-third decline since 1970.

North America has had a twenty-nine percent decrease in its bird population, 3 billion birds, since 1970 with a similar rate of decline on the continent of Europe. The cause is loss of habitat, pesticides and the reduction of insect populations that birds depend upon for food. 

The main causes of decline in wild animals across the globe listed in order of significance are: 

-Habitat loss on land and in the oceans from human impacts

-Direct exploitation of organisms

-Climate change


-Invasive species

Three-quarters of the Earth’s ice-free land-based environment and two-thirds of the marine based environment have been significantly degraded by human activity. 

According to the UN Global Diversity Outlook of 2014, seventy percent of the loss of terrestrial biodiversity is caused by agriculture and ranching.  One-third of the ice-free land surface of the Earth is used for crops and the grazing of livestock. 

The size of the world’s urban areas has doubled since 1980. 

More than half of all plant and animal species live in tropical forests. The Earth was once covered by 6 million square miles of tropical rain forests.  Only 2.4 million square miles remain.

In Asia, especially Indonesia, Cambodia and Thailand, the main contributors to the loss of wild animal populations are logging of old growth forests for pulpwood and building materials such as plywood and the replacement of forests with industrial scale palm oil plantations, the crop used in a large array of food, cosmetic and cleaning products.  

In Latin America the biggest driver of the destruction of tropical forests is the expansion of cattle ranching that is responsible for a loss of an astounding 97 million hectares of tropical forests during the last 25 years, an area larger than Montana, New Mexico and Colorado combined.  

Ninety-one percent of land deforested in the Amazon since 1970 has been converted to cattle ranches.  

Vast stands of tropical forests in Latin America are also being destroyed by large scale soybean farms with the harvests shipped to China and Europe for livestock feed.   

A shocking eighty-five percent of the world’s wetlands has been lost from 1700 to 2000, a rate of loss three times greater than the rate of loss of forests.  Wetlands are among the richest biomes for animal and plant species and they are the major source of fresh water for human consumption and agriculture.  

Three-quarters of the world’s freshwater lakes and rivers are used for crop production and the raising of livestock, resulting in more than 500,000 species with insufficient freshwater habitat remaining.

The freshwater species of mammals, birds, amphibians, reptiles and fish have experienced the most precipitous decline, mainly from the enormous loss of freshwater habitat and wetlands.  In the LPI these freshwater species have declined by an average of eighty-four percent since 1974 and continue at the the astounding rate of four percent decline per year. Freshwater animals have been monitored in many regions of the planet and while there are sharp declines in all regions, the greatest decline has occurred in Latin America and the Caribbean. 

Wetlands are essential to the health of the environment. They filter polluted and silty water, modulate floods, and in coastal zones, mangrove wetlands provide protection against dangerous storm surges. 

 In the coming decades scientists predict that the Climate Crisis will replace ranching and farming as the main cause of the decline of animal and plant species.  Rising temperatures, droughts, floods and wildfires have altered much of the world’s natural biomes.  Animals and plants can’t migrate or adapt to the rapid climactic changes to their habitat. 

Giant stands of forests on many continents have already seen a great reduction in their size and the forests that continue to be most at risk are:

Amazon Rain Forest 

Atlantic Forests of Brazil

Gran Chaco (Largest dry forest in South America)

Borneo (Island shared with Indonesia, Brunei and Malaysia)

Cerrado Wetlands in South America, mainly in Brazil

Chaco-Darien Moist Forests, mainly in western Colombia

Congo Basin

East Africa

Eastern Australia

Greater Mekong

New Guinea (Island shared with Indonesia and Papua New Guinea).

Sumatra (Indonesia) 

Global warming and the emissions of greenhouse gases threaten the survival of marine plants and animals and ultimately the human species that depends on the health of marine plants and animals for its own survival. 

Oceans are the biggest source of protein, providing sustenance for 3 billion people.  

The health of the oceans is being degraded by human activities that include development and destruction of natural coastal habitat and pollution from fertilizer runoff from the land. Rivers throughout the world discharge garbage, plastics, oil and industrial waste into the sea. Ocean acidification and rising temperatures of sea water are a direct result of carbon emissions into the atmosphere and the greenhouse effect. Overfishing threatens the survival of many fish stocks, and now excessive noise in the oceans from ships, oil rigs and other activities are disrupting the ability of fish and marine mammals to communicate and navigate. 

Thirty percent of the carbon emitted into the atmosphere by human activities is absorbed by the oceans and causes ocean acidification that inhibits marine animals, including shellfish and corals, from developing their shells and exoskeletons. The oceans absorb a whopping ninety-three percent of the heat that is trapped in the atmosphere from the greenhouse effect. If the oceans didn’t absorb this excess heat, the Earth’s atmosphere would be an alarming 97 F degrees hotter and the Earth would be uninhabitable.  

A remarkable fifty to eighty-five percent of the life-sustaining oxygen on the planet is produced by photosynthesis from phytoplankton, the tiny aquatic plants that float in the sunlit upper layers of the ocean.  Excess heat and carbon dioxide that the oceans absorb, threaten the survival of all marine plant and animal species.

Industrial fishing takes place in half of the world’s oceans. One-third of marine fish stocks are harvested at unsustainable levels, sixty percent are fished at the maximum amount that allows sustainability and only seven percent of fish are harvested at levels below what can be sustainably fished. 

Especially damaging to fish stocks and a healthy ocean environment is bottom trawling that drags nets across the ocean floor and brings up every marine species in its path, even those that are discarded as by-catch. It also damages the rich ocean floor ecosystem. 

Thirty-three percent of marine mammals, sharks and shark relatives are threatened with extinction. 

Overfishing has caused a decline of the global bluefin tuna population by ninety-six percent during the last 100 years.

Forty percent of amphibians are threatened with extinction.  

Terrestrial insects are declining at an abundance rate of about nine percent per decade. Pollination loss from animals, including insects, especially bees, is affecting seventy-five percent of food crops, an estimated $235 to $577 billion food crop value. Insect population decline is caused by destruction of habitat, commercial farming, pesticides, urbanization, introduced species and climate change. 

A key to measuring the loss of wild animal species based on loss and degradation of their natural habitat, is the reduced range of a specific animal species. Of 177 species of land mammals analyzed to calculate their range loss, it has been determined that fifty-six percent of land mammals across Africa, Asia, Australia, and Europe have experienced a sixty percent loss of their range, the area where the species lives and migrates for food, water and reproduction.  For land mammals, from 1900 to 2015, 58,000 local populations of the 177 land mammals studied have entirely disappeared. 

All humans alive today plus our livestock represent ninety-six percent of the weight of all mammals on the Planet and the remaining four percent are the remaining wild animals.

Half a million or about nine percent of the world’s 5.9 million terrestrial species will not survive without habitat restoration. 

Since the major driver of loss of animal abundance and species is the reduction of natural habitat caused by the high rate of deforestation, especially in the tropics from expansion of cattle grazing land, the greatest impact an individual can have to help reduce habitat loss is to change her diet from animal-based protein to plant-based protein.  

Meat and dairy production uses eighty-three percent of the world’s farmland but contributes only thirty-five percent of food protein and eighteen percent of calories for human populations.  

“Dwindling population sizes and range shrinkages amount to massive anthropogenic erosion of biodiversity and the ecosystem services essential to civilization. This biological annihilation underlines the seriousness for humanity of Earth’s Sixth Mass Extinction event.” Proceedings of the National Academy of Sciences, USA, 2017.

The biggest source of greenhouse gases is the generation of electric power from fossil fuels, mainly coal and natural gas. Conversion from fossil fuels to renewable sources of wind and solar for electric power generation is essential to fight the Climate Crisis and its destructive effect on natural areas of our planet. The second biggest contributor to greenhouse gases to the globe is the transportation sector. Changing to electric vehicles for individual and commercial use is long overdue. 

The 2020 UN Convention on Biological Diversity calls for the creation and expansion of national parks, marine sanctuaries and other wildlife protected zones on one-third of the Earth’s surface by 2030 to avoid the planet’s Sixth Mass Extinction event, aptly titled the Anthropocene, from “anthropos,” or human. Presently only fifteen percent of the world’s land surface and seven percent of the oceans are set aside as protected zones for wild species. protected. 

The Biden White House announced a comprehensive environmental plan on January 27, 2021 that includes a goal of conserving at least thirty percent of US land and waters by 2030. This would be a great step forward in protecting wild animals and plants from loss of natural habitat, the biggest threat to species.


(1) The LPI is managed by the Zoological Society of London in cooperation with the Wildlife Fund for Nature and monitors the rate of loss of vertebrate species around the world. 

Many of the statistics in this report are taken directly as quotes from the references below: 

Living Planet Index, Living Planet Report, Zoological Society of London and World Wildlife Fund for Nature, 2020. 

Proceedings of the National Academy of Sciences, USA, “Biological Annihilation Via the Ongoing Sixth Mass Extinction Signaled by Vertebrate Populations and Declines.”  July 25, 2017. 

UN Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). April 2019. 

International Union for Conservation of Nature Red List of Threatened Species

Center for Biological Diversity, “A Plan to Halt the Global Extinction Crisis.”  2020. 

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