How does deforestation impact wildlife and biodiversity? What you need to know.

Forests cover 31% of the land on our planet, and they are critically important for stabilising the climate, absorbing approximately 2.6 billion tonnes of CO2 each year. They also provide more than 86 million green jobs and support the livelihoods of many more. An estimated 880 million people spend part of their time collecting fuel wood or producing charcoal, and of people living in extreme poverty, over 90% are dependent on forests for at least part of their livelihoods. 

However, forests aren’t just important to us. They are also important to the wildlife that lives within them. From the boreal forests in the far North to the famously biodiverse rainforests of the tropics, forests are thought to provide habitat for 80% of amphibian species, 75% of bird species and 68% of mammal species. 

But these forests are being destroyed and degraded at an alarming rate. Since 1990, it is estimated that 420 million hectares of forest have been lost through conversion to other land uses. In addition, more than 100 million hectares of forest are adversely affected by forest fires, pests, diseases, invasive species, drought, and other events that are exacerbated by human activity. The main driver of deforestation and associated loss of biodiversity continues to be agricultural expansion, particularly large-scale commercial agriculture including cattle ranching and cultivation of soybean and oil palm. You can read more about the sectors driving deforestation here.

We decided to explore how deforestation affects the wildlife that lives in and around the world’s forests.

Wildlife is increasingly becoming threatened by human activities and changing climates. The IUCN Red List of Threatened species is the world’s most comprehensive information source of the global extinction risk of animals, fungi, and plant species. It lists species and classifies how threatened they are according to the following categories: Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near threatened and Least Concern.

Approximately 80% of the world’s land-based species live in forests. When these forests are destroyed, animals lose their homes and are often unable to survive in the small fragments of forests left behind. The destruction and fragmentation of forests is the biggest driver of extinction across the world. A 2017 study of more than 19,000 species of birds, amphibians, and mammals found that deforestation substantially increased the odds of species being listed on the IUCN red list as threatened and exhibiting declining populations. Even localised or small-scale deforestation can result in extinctions, as many species exist within small geographic areas.

There are a number of ways in which deforestation can impact wildlife living within and around forests.

Habitat loss – Habitat loss is probably the biggest threat to the variety of life on Earth today. It is identified as a main threat to 85% of all species described in the IUCN’s Red List. Deforestation can lead to a direct loss of wildlife habitat, with the removal of trees and other types of vegetation reducing the available food, shelter, and breeding habitat for animals. For example, tigers have lost an estimated 95% of their historic range as their habitat has been destroyed, degraded, and fragmented by human activities.

Habitat fragmentation – While evidently interlinked, habitat loss and fragmentation are distinct concepts. Habitat loss, in relation to forests, refers to a reduction in the area of a forest, whilst habitat fragmentation involves the division of a once continuous area of forest into multiple patches. Smaller fragments of forest can support fewer animals and smaller populations are more at risk of extinction. For example, giant pandas are particularly affected by habitat fragmentation, and many giant panda populations are small and isolated, resulting in limited gene flow and increased risk of inbreeding and its associated disadvantages.

Human interaction – The destruction of forests and the splitting up into smaller areas makes them more accessible to humans. This increases the occurrence of human-wildlife conflict, where the needs and behaviour of wildlife impacts negatively on humans, or when humans negatively affect wildlife. For example, this can include increased hunting and poaching of animals as they become more accessible to hunters, increased occurrence of roadkill and road traffic accidents, and wildlife causing destruction of property, crops, livestock, and even human lives. Increased contact with humans can cause species numbers to dwindle, and even go extinct. An example is in the palm oil plantations of Africa, Latin America and Asia where large areas of rainforest are cleared to grow palm crops. Orangutans, tigers, elephants, rhinos and many other species are increasingly isolated, and their sources of food and shelter are in decline.

Change in canopy structure – The forest canopy plays an important role blocking the sun’s rays during the day and retaining heat at night. Removing trees deprives the forest of portions of its canopy, and this disruption leads to more extreme temperature swings which can be harmful to animals.

These are some of the general effects that deforestation is having on species that reside in the world’s forests. But what about the areas that Ecologi works in? What animals are being affected by deforestation – and how are we helping?

The island of Madagascar split from Africa over 160 million years ago, and since then it has developed its own distinct ecosystems and extraordinary wildlife. An estimated 95% of Madagascar’s reptiles, 89% of its plants and 92% of its mammals are endemic, meaning they exist nowhere else on Earth. 

However, more than 90% of Madagascar’s original forests have been destroyed, displacing entire animal species. The small-scale but widespread clearance of forests, through slash and burn agriculture and logging for firewood and charcoal production is jeopardising the island’s habitats. As a result, several species such as lemurs and chameleons that evolved here over millions of years may become extinct before the end of the century. Almost a third (31%) of all lemur species in Madagascar are now Critically Endangered – just one step away from extinction – with 98% of them threatened. Among those recently listed as critically endangered in 2020 include the Verreaux’s Sifaka lemur and the Madame Berthe’s Mouse Lemur, the smallest primate in the world.

Particularly of concern in Madagascar are the mangrove forests. Madagascar contains 2% of the world’s mangroves, accounting for 20% of African mangrove forests. However these are being deforested at alarming rates, and entire mangrove estuaries are now gone, leaving the bare earth to wash away into the sea. Mangroves, as well as storing massive amounts of carbon, are really important for wildlife. They provide breeding grounds and nurseries for numerous fish species and shellfish, and help trap sediments that might otherwise adversely affect habitats for marine life such as seagrass beds and coral reefs. 

The mangroves in Madagascar have critical importance for numerous endemic species that are listed on the IUCN Red List. These include bird species that use the mangroves for nesting and roosting: the Madagascar Teal listed as Endangered; the Madagascan Fish-Eagle listed as Critically Endangered; the Madagascar Heron listed as Endangered; and Malagasy Sacred Ibis listed as Endangered.

This is why the mangrove planting projects we support in the north west of the island are so important.  So far, the Ecologi community has funded the planting of over 45.6 million trees in Madagascan mangrove projects!

This East African country has rich and unique ecosystems that are home to 236 species of mammal, 740 species of bird and 5,692 species of vascular plant. Additionally, Mozambique is the home to 200 endemic mammal species, such as the African elephant.

Poaching for ivory and meat has traditionally been the major cause of decline for African elephants,however currently the biggest perceived threat is the loss and fragmentation of habitat, caused by ongoing human population expansion and rapid land conversion. This has increased the amount of human-elephant conflict, which further aggravates the threat to elephant populations.

In Mozambique, the Ecologi community has already funded the planting of over 5.9 million trees, helping to bring back a thriving ecosystem and prevent further deforestation by alleviating poverty and creating a long term maintenance and protection plan.

One of Eden Reforestation Project’s tree planting sites in Nicaragua that we have supported is within the Bosawas Biosphere Reserve, which forms part of the Mesoamerican Biological Corridor. This is a corridor that stretches between South and North America, connecting habitats and areas of tropical forest together to allow the movement of animals from one end of the corridor to the other.

This is especially important for jaguars, which are endangered by habitat loss and fragmentation. Jaguars are the largest cat in the Americas, and have large round heads, short legs and a beautiful coat that is dotted with dark spots. These majestic animals are under serious pressure as their forest homes are being destroyed. Deforestation rates in Latin America are the highest in the world, alongside tropical Africa. Fragmentation and displacement frequently lead to lowering of density of jaguars in forest patches. Their range has also contracted significantly: jaguars used to be found all the way from south-western USA down to central Argentina, but they now occupy less than half of their historical range.

Jaguars are a single species, with no subspecies, meaning that all populations are connected throughout their range. Therefore, connectivity is vital to these animals, and ensuring links throughout the Americas is critical to maintaining populations. If the corridor is cut up by roads and development this leads to isolated populations with fewer animals. These populations have less genetic diversity and are more vulnerable to extinction. 

At Ecologi, not only have we funded the planting of trees in Nicaragua to help maintain this corridor, but we also funded a project to protect existing rainforest in the Mesoamerican Biological Corridor within Guatemala, thus helping to facilitate the movement of jaguars between different areas.

Deforestation is not just a tropical phenomenon. Vast areas of Scottish forests have also been cleared, and without human intervention it is likely that much of Scotland would be covered by trees. Ever since the first foresters entered Scotland’s ancient woodlands over 6,000 years ago, its trees and forests have been felled and harvested to make space for agriculture, homes and infrastructure. By the early 20th century, forest cover in Scotland, as well as in the rest of the UK, was reduced to around 5%. This has since increased to around 18.5%, which is higher than the rest of the UK, but still well below the EUs average of 43%.

Scotland’s forests and woodlands support a diverse range of over 1,000 species. These include 172 protected species, including the pine marten, twinflower, crested tit, scottish crossbill, black grouse and the capercaillie, as well as an estimated 75% of the UK’s red squirrel population.

A reforestation project in Scotland that the Ecologi community has supported is called Dalry, once home to native Scottish wildlife but which had become barren. This project is allowing wildlife to come back to this area. Jim from the Future Forest Company, our tree planting partner on this site, says, “you now see hen harriers, an endangered species, regularly on site, when before the sighting of a bird of prey was rare”. This is a great sign that the ecosystem is starting to recover.

The WWF estimates that more than 80% of global deforestation between 2015-30 will take place on 11 deforestation ‘fronts’. One of these is eastern Australia, in the states of Queensland and New South Wales (NSW). In Australia, tree-clearing is largely undertaken to create pasture for livestock, particularly for beef cattle production.

The impact of deforestation on wildlife is significant, with 964 of the 1250 Australian terrestrial animals’ species listed as threatened, with habitat fragmentation identified as a threat. These include Carnaby’s cockatoo, the southern cassowary, Bennet’s tree kangaroo, and the Cape York rock wallaby, as well as the iconic koala. It is also estimated that, in NSW, between 4.9-10 million native wild animals are killed in the process of tree-clearing each year.

Koalas are currently classified as vulnerable with the key threat being continued habitat destruction, fragmentation, and modification, as the forests they live in are being rapidly cleared. Small populations of koalas in isolated sections of habitat are at the greatest risk of extinction. 

The reforestation project in NSW that the Australian Ecologi subscribers can support was established to try to protect the local koala population in the Northern rivers of NSW. The main goal is to establish a wildlife corridor by planting 50,000 trees to allow koalas to move between habitat fragments and help their populations to bounce back.

More than 150 tree species can be found in Appalachia, making it one of the most diverse ecological regions in North America. The Appalachians are home to more than 200 globally rare plants and animals, and more than 15,000 documented wildlife species, including the caribou, moose, black bear, wild boar, fox, and numerous small mammals, thrive there.

Appalachia’s forests are of particular importance as a breeding ground for migratory birds that spend the breeding season within this region, before flying south to overwinter in Mexico and Central and South America. These species include the Baltimore oriole, broad-winged hawk, red-eyed vireo, ruby-throated hummingbird, scarlet tanager, Tennessee warbler, and the cerulean warbler. 

However, the resource wealth of the region has meant that much of the forest has been deforested and degraded by mining and timber operations, with an estimated 83% of the original habitat having been lost. Approximately 80% of the cerulean warbler population breeds within the Appalachian forests. This species is threatened by the conversion of its forest habitat for agricultural or urban use and the fragmentation of habitat left behind. 

A planting project in Appalachia that Ecologi subscribers can support is planting native tree species to help the entire ecosystem recover. This will help to preserve the unique biodiversity of the Appalachian region.

We couldn’t talk about deforestation without mentioning the Amazon rainforest. This is the world’s largest rainforest and river system, which contains nearly a third of all the tropical rainforests left on Earth. Despite covering only 1% of the planet’s surface, the Amazon is home to 10% of all known wildlife species, with many more being described each year.

However, as a result of the major pressures being exerted on the Amazon (large-scale agriculture and cattle ranching, small-scale agriculture, road and hydropower infrastructure, mining and logging), it is being deforested on a massive scale. 20% has already been lost.

As well as releasing vast amounts of carbon into the atmosphere, this destruction and deforestation has numerous, complex impacts on the wildlife that lives within the forests. One example of an animal under threat from deforestation in the Amazon is the black spider monkey. This is one of seven species of spider monkey found in Latin America, and it is one of the largest primates in South America. They play an essential role in the tropical rainforest ecosystem, aiding seed dispersal and thus helping the forest environment to continue to grow and thrive. However, these monkeys are threatened by the destruction of forests. They prefer mature tropical forests and seldom venture into disturbed habitats. This means that these monkeys are especially vulnerable to the effects of forest fragmentation.

Black spider monkeys don’t do so well in newly reforested areas, and that’s why some of the  projects Ecologi has supported (see here, here and here) that protect existing rainforests in the Amazon are so important. These projects preventing deforestation in Brazil help to preserve the habitats of the black spider monkey and many other creatures.

In fact, one project is designed partly with a specific species in mind. This avoided deforestation project in Almeirim, Brazil, has objectives to protect the critically endangered Black bearded Saki (Chiropotes satanas). This species has decreased by at least 80% in the last 30 years and this trend is predicted to continue. In a scenario without the project we are helping to fund, the population trend of this species within this area is decreasing and becoming more threatened, mainly due to the loss of habitat caused by deforestation. However, in the scenario with this project, it is predicted there will be improvements in the trend of the population of Chiropotes satanas.

Deforestation is also impacting the ability of species to adapt to future climate change. For millennia, wildlife around the world has moved up and down mountains, and towards and away from the equator in order to cope with changes in the world’s temperature. However, the deforestation of tropical forests is creating a patchwork landscape where natural habitat is fragmented. Recent research has found that most tropical forest habitat is currently too disconnected to provide pathways to cooler climates, meaning that wildlife will struggle to escape the impacts of climate change.

The majority of the world’s wildlife relies on forests for their food, shelter, and nesting sites. Worldwide, species are being threatened as their homes are torn down at alarming rates to make way for agriculture and infrastructure. It’s really important that we do our best to combat deforestation, not only for our sake, but for the sake of the animals and plants that live there. There are lots of organisations that are doing great work in this field.