RAINFOREST INFORMATION

A Place Out of Time: Tropical Rainforests and the Perils They Face - information on tropical forests, deforestation, and biodiversity

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BACKGROUND INFORMATION ON THE RAINFOREST

Rainforests are forest ecosystems characterized by high levels of rainfall, an enclosed canopy and high species diversity. While tropical rainforests are the best-known type of rainforest and the focus of this section of the web site, rainforests are actually found widely around the world, including temperate regions in Canada, the United States, and the former Soviet Union.

Tropical rainforests typically occur in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn, latitudes that have warm temperatures and relatively constant year-round sunlight. Tropical rainforests merge into other types of forest depending on the altitude, latitude, and various soil, flooding, and climate conditions. These forest types form a mosaic of vegetation types which contribute to the incredible diversity of the tropics.

The bulk of the world's tropical rainforest occurs in the Amazon Basin in South America. The Congo Basin and Southeast Asia, respectively, have the second and third largest areas of tropical rainforest. Rainforests also exist on some the Caribbean islands, in Central America, in India, on scattered islands in the South Pacific, in Madagascar, in West and East Africa outside the Congo Basin, in Central America and Mexico, and in parts of South America outside the Amazon. Brazil has the largest extent of rainforest of any country on Earth.

Rainforests provide important ecological services, including storing hundreds of billions of tons of carbon, buffering against flood and drought, stabilizing soils, influencing rainfall patterns, and providing a home to wildlife and Indigenous people. Rainforests are also the source of many useful products upon which local communities depend.

While rainforests are critically important to humanity, they are rapidly being destroyed by human activities. The biggest cause of deforestation is conversion of forest land for agriculture. In the past subsistence agriculture was the primary driver of rainforest conversion, but today industrial agriculture — especially monoculture and livestock production — is the dominant driver of rainforest loss worldwide. Logging is the biggest cause of forest degradation and usually proceeds deforestation for agriculture.

Organization of this site

The rainforest section of Mongabay is divided into ten "chapters" (the original text for the site was a book, but has since been adapted for the web), with add-on content in the form of special focal sections (e.g. The Amazon, the Congo, REDD, New Guinea, Sulawesi, Forests in Brazil, etc), appendices, and other resources.

There is also a version of the site geared toward younger readers at kids.mongabay.com.

ABOUT THE RAINFOREST (SUMMARY)

RAINFOREST DISTRIBUTION AND CHARACTERISTICS

Each rainforest is unique, but there are certain features common to all tropical rainforests.

• Location: rainforests lie in the tropics.
• Rainfall: rainforests receive at least 80 inches (200 cm) of rain per year.
• Canopy: rainforests have a canopy, which is the layer of branches and leaves formed by closely spaced rainforest trees some 30 meters (100 feet) off the ground. A large proportion of the plants and animals in the rainforest live in the canopy.
• Biodiversity: rainforests have extraordinarily highs level of biological diversity or “biodiversity”. Scientists estimate that about half of Earth's terrestrial species live in rainforests.
• Ecosystem services: rainforests provide a critical ecosystem services at local, regional, and global scales, including producing oxygen (tropical forests are responsible for 25-30 percent of the world's oxygen turnover) and storing carbon (tropical forests store an estimated 229-247 billion tons of carbon) through photosynthesis; influencing precipitation patterns and weather; moderating flood and drought cycles; and facilitating nutrient cycling; among others.

The global distribution of tropical rainforests can be broken up into four biogeographical realms based roughly on four forested continental regions: the Afrotropical, the Australiasian, the Indomalayan/Asian, and the Neotropical. Just over half the world's rainforests lie in the Neotropical realm, roughly a quarter are in Africa, and a fifth in Asia.

These realms can be further divided into major tropical forest regions based on biodiversity hotspots, including:

1. Amazon: Includes parts of Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Venezuela
2. Congo: Includes parts of Cameroon, Central African Republic, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Republic of Congo
3. Australiasia: Includes parts of Australia, Indonesian half of New Guinea, Papua New Guinea
4. Sundaland: Includes parts of Brunei, Indonesia, Malaysia, Singapore
5. Indo-Burma: Includes parts of Bangladesh, Cambodia, China, India, Laos, Myanmar, Thailand, Vietnam
6. Mesoamerica: Includes parts of Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama
7. Wallacea: Sulawesi and the Maluku islands in Indonesia
8. West Africa: Includes parts of Benin, Cameroon, Côte d'Ivoire, Ghana, Guinea, Liberia, Nigeria, Sierra Leone, Togo
9. Atlantic forest: Includes parts of Argentina, Brazil, Paraguay
10. Choco: Includes parts of Colombia, Ecuador, Panama

Other countries that have large areas of rainforest include Bolivia, Cameroon, Central African Republic, Ecuador, Gabon, Guyana, India, Laos, Malaysia, Mexico, Myanmar, Papua New Guinea, Republic of Congo, Suriname, and Venezuela.

Cover and loss by rainforest region

RAINFOREST STRUCTURE

Rainforests are characterized by a unique vegetative structure consisting of several vertical layers including the overstory, canopy, understory, shrub layer, and ground level. The canopy refers to the dense ceiling of leaves and tree branches formed by closely spaced forest trees. The upper canopy is 100-130 feet above the forest floor, penetrated by scattered emergent trees, 130 feet or higher, that make up the level known as the overstory. Below the canopy ceiling are multiple leaf and branch levels known collectively as the understory. The lowest part of the understory, 5-20 feet (1.5-6 meters) above the floor, is known as the shrub layer, made up of shrubby plants and tree saplings.

RAINFOREST BIODIVERSITY

Tropical rainforests support the greatest diversity of living organisms on Earth. Although they cover less than 2 percent of Earth’s surface, rainforests house more than 50 percent of the plants and animals on the planet.

THE RAINFOREST CANOPY

In the rainforest most plant and animal life is not found on the forest floor, but in the leafy world known as the canopy. The canopy, which may be over 100 feet (30 m) above the ground, is made up of the overlapping branches and leaves of rainforest trees. Scientists estimate that more than half of life in the rainforest is found in the trees, making this the richest habitat for plant and animal life.

The conditions of the canopy are markedly different from the conditions of the forest floor. During the day, the canopy is drier and hotter than other parts of the forest, and the plants and animals that live there have adapted accordingly. For example, because the amount of leaves in the canopy can make it difficult to see more than a few feet, many canopy animals rely on loud calls or lyrical songs for communication. Gaps between trees mean that some canopy animals fly, glide, or jump to move about in the treetops. Meanwhile plants have evolved water-retention mechanisms like waxy leaves.

Scientists have long been interested in studying the canopy, but the height of trees made research difficult until recently. Today the canopy is commonly accessed using climbing gear, rope bridges, ladders, and towers. Researchers are even using model airplanes and quadcopters outfitted with special sensors — conservation drones — to study the canopy.

The rainforest floor

The rainforest floor is often dark and humid due to constant shade from the leaves of canopy trees. The canopy not only blocks out sunlight, but dampens wind and rain, and limits shrub growth.

Despite its constant shade, the ground floor of the rainforest is the site for important interactions and complex relationships. The forest floor is one of the principal sites of decomposition, a process paramount for the continuance of the forest as a whole. It provides support for trees responsible for the formation of the canopy and is also home to some of the rainforest's best-known species, including gorillas, tigers, tapirs, and elephants, among others.

Rainforest waters

Tropical rainforests support some of the largest rivers in the world, like the Amazon, Mekong, Negro, Orinoco, and Congo. These mega-rivers are fed by countless smaller tributaries, streams, and creeks. For example, the Amazon alone has some 1,100 tributaries, 17 of which are over 1,000 miles long. Although large tropical rivers are fairly uniform in appearance and water composition, their tributaries vary greatly.

Rainforest waters are home to a wealth of wildlife that is nearly as diverse as the biota on land. For example, more than 5,600 species of fish have been identified in the Amazon Basin alone.

But like rainforests, tropical ecosystems are also threatened. Dams, deforestation, channelization and dredging, pollution, mining, and overfishing are chief dangers.

Rainforest people

Tropical rainforests have long been home to tribal peoples who rely on their surroundings for food, shelter, and medicines. Today very few forest people live in traditional ways; most have been displaced by outside settlers, have been forced to give up their lifestyles by governments, or have chosen to adopt outside customs.

Of the remaining forest people, the Amazon supports the largest number of Indigenous people living in traditional ways, although these people, too, have been impacted by the modern world. Nonetheless, Indigenous peoples' knowledge of medicinal plants remains unmatched and they have a great understanding of the ecology of the Amazon rainforest.

In Africa there are native forest dwellers sometimes known as pygmies. The tallest of these people, also called the Mbuti, rarely exceed 5 feet in height. Their small size enables them to move about the forest more efficiently than taller people.

There are few forest peoples in Asia living in fully traditional ways. The last nomadic people in Borneo are thought to have settled in the late 2000's. New Guinea and the Andaman Islands are generally viewed as the last frontiers for forest people in Asia and the Pacific.

Deforestation

In recent decades there has been an important shift in deforestation trends. Today export-driven industries are driving a bigger share of deforestation than ever before, marking a shift from previous decades, when most tropical deforestation was the product of poor farmers trying to put food on the table for their families. There are important implications from this change. While companies have a greater capacity to chop down forests than small farmers, they are more sensitive to pressure from environmentalists. Thus in recent years, it has become easier—and more ethical—for green groups to go after corporations than after poor farmers.

Rainforests are also threatened by climate change, which is contributing to droughts in parts of the Amazon and Southeast Asia. Drought causes die-offs of trees and dries out leaf litter, increasing the risk of forest fires, which are often set by land developers, ranchers, plantation owners, and loggers.

Rainforest importance

While rainforests may seem like a distant concern, they are critically important for our well-being. Rainforests are often called the lungs of the planet for their role in absorbing carbon dioxide, a greenhouse gas, and producing oxygen, upon which all animals depend for survival. Rainforests also stabilize climate, house incredible amounts of plants and wildlife, and produce nourishing rainfall all around the planet.

Rainforests:

• Help stabilize the world’s climate: Rainforests help stabilize the world’s climate by absorbing carbon dioxide from the atmosphere. Scientists have shown that excess carbon dioxide in the atmosphere from human activities is contributing to climate change. Therefore, living rainforests have an important role in mitigating climate change, but when rainforests are chopped down and burned, the carbon stored in their wood and leaves is released into the atmosphere, contributing to climate change.
• Provide a home to many plants and animals: Rainforests are home to a large number of the world’s plant and animals species, including many endangered species. As forests are cut down, many species are doomed to extinction.
• Help maintain the water cycle: The role of rainforests in the water cycle is to add water to the atmosphere through the process of transpiration (in which plants release water from their leaves during photosynthesis). This moisture contributes to the formation of rain clouds, which release the water back onto the rainforest. In the Amazon, 50-80 percent of moisture remains in the ecosystem’s water cycle. When forests are cut down, less moisture goes into the atmosphere and rainfall declines, sometimes leading to drought. Rainforests also have a role in global weather patterns. For example researchers have shown that forests in South America affect rainfall in the United States, while forests in Southeast Asia influence rain patterns in southeastern Europe and China. Distant rainforests are therefore important to farmers everywhere.
• Protect against flood, drought, and erosion: Rainforests have been compared to natural sponges, moderating flood and drought cycles by slowing run-off and contributing moisture to the local atmosphere. Rainforests are also important in reducing soil erosion by anchoring the ground with their roots. When trees are cut down there is no longer anything to protect the ground, and soils are quickly washed away with rain. On steep hillsides, loss of forest can trigger landslides.
• Are a source for medicines and foods and support forest-dependent people: People have long used forests as a source of food, wood, medicine, and recreation. When forests are lost, they can no longer provide these resources. Instead people must find other places to get these goods and services. They also must find ways to pay for the things they once got for free from the forest.

Rainforest conservation

Rainforests are disappearing very quickly. The good news is there are a lot of people who want to save rainforests. The bad news is that saving rainforests will be a challenge as it means humanity will need to shift away from business-as-usual practices by developing new policies and economic measures to creative incentives for preserving forests as healthy and productive ecosystems.

Over the past decade there has been considerable progress on several conservation fronts. Policymakers and companies are increasingly valuing rainforests for the services they afford, setting aside large blocks of forests in protected areas and setting up new financial mechanisms that compensate communities, state and local governments, and countries for conserving forests. Meanwhile, forest-dependent people are gaining more management control over the forests they have long stewarded. Large international companies are finally establishing policies that exclude materials sourced via deforestation. People are abandoning rural areas, leading to forest recovery in some planes.

But the battle is far from over. Growing population and consumption means that rainforests will continue to face intense pressures. At the same time, climate change threatens to dramatically alter temperatures and precipitation patterns, potentially pushing some forests toward critical tipping points.

Thus the future of the world's rainforests in very much in our hands. The actions we take in the next 20 years will determine whether rainforests, as we currently know them, are around to sustain and nourish future generations of people and wildlife.

The Latest News on Rainforests

Relief in Sri Lanka as key threat to nonprotected forests is repealed (Nov 20 2024)
- A 2020 government decree that transferred administrative control of nonprotected forests in Sri Lanka to local governments has been formally revoked by the country’s new government.
- The move follows its overturning by the country’s Supreme Court, where environmental activists argued it could allow the release of these forests for development projects without proper environmental assessments.
- Known as “other state forests” (OSFs) or “residual forests,” they harbor high levels of biodiversity and serve as crucial connectivity or buffer zones that help reduce human-wildlife conflict.
- They could also play a key role in the government’s commitment to the 30×30 initiative of protecting 30% of land and sea area by 2030.

Experts welcome Brazil’s revived reforestation plan as much-needed boost (Nov 20 2024)
- By 2030, Brazil aims to restore 12 million hectares (30 million acres) of degraded land through the Planaveg initiative, revised and launched by the government at the recent COP16 biodiversity summit in Cali, Colombia.
- Experts have welcomed the move amid growing international commitments to protect biodiversity and stabilize the climate, but point to challenges such as securing resources and social mobilization.
- As ambitious as the target is, it still falls short of the 20.7 million hectares (51.2 million acres) of native vegetation that have been illegally degraded just on private rural plots.

Five-year rainforest tech competition culminates with four winners (Nov 20 2024)
- Limelight Rainforest, a team of ecologists, robotics engineers and Indigenous scientists, has won first place in a $10 million rainforest tech competition.
- At the finals in Brazil in July, the team deployed canopy rafts, drones and artificial intelligence models to identify and detect the highest amount of biodiversity from a forest plot within 24 hours.
- Three other teams were also recognized for their work in developing tech solutions to monitor rainforests around the world.
- The five-year XPRIZE Rainforest competition was launched in 2019 to identify solutions to automate rainforest monitoring.

Scottish salmon farms seek growth despite mounting fish deaths and environmental concerns (Nov 20 2024)
- Scotland is the world’s third-largest producer of farmed Atlantic salmon (Salmo salar), after Norway and Chile.
- The industry is seeking to significantly increase production in Scotland, driven by growing export demand.
- However, it faces ethical concerns over mounting fish mortality, as well as environmental concerns about pollution, the proliferation of sea lice affecting wild salmon, and opposition from several local communities.
- Industry members acknowledge the challenge of growing salmon amid rising sea temperatures, but say Scottish salmon farms have made progress in managing sea lice and other health challenges.

Indigenous guardians embark on a sacred pact to protect the lowland tapir in Colombia (Nov 20 2024)
- An Indigenous-led citizen conservation project in the community of Musuiuiai in Putumayo, Colombia, aims to obtain data on the lowland tapir’s presence and understand the environmental factors affecting the species.
- According to spiritual beliefs, a divination from an elder in the 1990s pushed the community to move to a high-priority region for tapir conservation. Beliefs in the mammal’s sacred status supports conservation efforts.
- The lowland tapir (Tapirus terrestris) is listed as vulnerable to extinction on the IUCN Red List; in Colombia, it’s threatened by habitat loss and hunting.
- Using a biocultural approach to conservation, Musuiuiai was named an Indigenous and Community Conserved Area (ICCA), whose members now hope to reduce tapir hunting in neighboring tribes through outreach and collaboration.

Camera traps reveal little-known Sumatran tiger forests need better protection (Nov 20 2024)
- A new camera-trapping study in Indonesia’s Aceh province has identified an ample but struggling population of Sumatran tigers, lending fresh urgency to calls from conservationists for greater protection efforts in the critically endangered subspecies’ northernmost stronghold forests.
- The study focused on the Ulu Masen Ecosystem, an expanse of unprotected and little-studied forest connected to the better-known Leuser Ecosystem, the only place on Earth that houses rhinos, tigers, elephants and orangutans.
- The big cat population and its prey likely contend with intense poaching pressure, the study concludes; their forest home is also under threat from development pressure, illegal logging, rampant mining and agricultural encroachment.
- As a key part of the Leuser–Ulu Masen Tiger Conservation Landscape, experts say Ulu Masen merits more conservation focus to protect the tigers, their prey populations and their habitats.

‘Scratching the surface’ of Nepal butterfly research: Interview with Sanej Suwal (Nov 20 2024)
- With 692 identified species, including more than two dozen endemic, Nepal is an important habitat for butterflies. However, research is in its infancy due to insufficient funding, limited public interest and a lack of cultural emphasis on butterfly conservation.
- Sanej Suwal is one of a handful of researchers dedicated to butterfly research in Nepal, balancing species studies with public awareness initiatives. He organized Nepal’s first Big Butterfly Count, a citizen science initiative.
- Butterflies in Nepal likely face threats from climate change, habitat loss and urbanization. Despite their importance, butterfly research struggles with minimal funding and institutional recognition, requiring more researchers and global support to expand knowledge and conservation efforts.

The plastics crisis is now a global human health crisis, experts say (Nov 19 2024)
- Plastics can contain thousands of different chemicals, many of them linked to cancer and reproductive harm, and many never tested for safety.
- Multiple studies are now finding these chemicals, along with microplastics, throughout the human body, raising alarm among scientists about widespread health effects, including reduced fertility and increased obesity.
- Research points to a correlation between the presence of microplastics and endocrine disrupting plasticizers in the human body and a variety of serious maladies, but tracing a direct causal line is very difficult given the complexity and number of plastics and the industry’s lack of transparency regarding its products.
- Many scientists and nations are calling for a binding plastics treaty to limit global plastic production. But this week the U.S. took a weaker position; it now supports a policy in which nations set their own voluntary targets for reducing production. Negotiations to determine the final treaty language begin at a UN summit in Busan, Korea, running Nov. 25 – Dec. 1.

Hopes and fears for the Amazon: Interview with botanist Hans ter Steege (Nov 19 2024)
- Dutch researcher and tree expert Hans ter Steege is the founder of the Amazon Tree Diversity Network, which brings together hundreds of scientists studying the rainforest to map and understand the region’s biodiversity.
- Ter Steege says the rainforest is in danger of collapse: If the deforestation in Brazil’s Pará state continues at the rate of the year 2000, he warns, “then our models show there will be hardly anything left by 2050.”
- Large trees are dying faster in the Amazon, he said, as they face a greater evaporation demand, which they can no longer meet with the water they extract from the soil, as there are more droughts and less rainfall.
- If the forest collapses, Brazil’s aerial water supply system — and its agriculture — will collapse, Ter Steege says.

Biodiversity credit approaches multiply as concerns cloud confidence (Nov 19 2024)
- In recent years, biodiversity credit projects and the methods to calculate their value have proliferated, seen by some as a way to finance the $700 billion gap in conservation funding identified in the 2022 Global Biodiversity Framework.
- Credits involve payment for measurable outcomes beneficial to nature, ranging from increases in species diversity at a site to securing land rights for Indigenous communities.
- Critics of biodiversity credits have voiced concerns about comparing outcomes across ecosystems, especially if buyers will use the credits for offsetting. They also say focusing on biodiversity credits is a distraction.
- Proponents argue for bolstering biodiversity credit integrity and confidence in the markets to boost demand. Projections by the World Economic Forum suggest the market could reach $7 billion by 2030, though less than $2 million in credits have been sold so far.

‘Historic’ decision for the Batwa & DRC gorilla park faces hurdles — and hope (Nov 19 2024)
- The African Commission on Human and Peoples’ Rights determined that the eviction of thousands of Batwa from Kahuzi-Biega National Park in the 1970s was a human rights violation. However, months later, questions remain about whether and how the government will implement the commission’s 19 recommendations to address the situation.
- The return of Batwa to their ancestral lands in the park, paying them compensation and a public apology for all the Batwa suffered are among the key recommendations the Batwa and sources highlighted. Implementation would be challenging, but necessary from a human rights standpoint, they said, while breaking down the process.
- Researchers say there lacks evidence that modern-day Batwa are custodians of the forest and environmentalists highlight the need to build community-centered conservation projects that help Batwa live sustainably on their land in the park or find a balance that works for both the Batwa and park officials.
- The DRC and park officials have not yet commented on the possibility of implementation, but conservation authorities and the park’s partners and donors say they are taking steps to reconcile Indigenous rights and the protection of biodiversity.

Dam displaces farmers as drought parches Indonesia’s Flores Island (Nov 19 2024)
- In 2015, Indonesia announced the construction of seven dams to provide water in East Nusa Tenggara province, an eastern region of the archipelago where access to freshwater is scarce during the annual dry season.
- One of the national priority dams, the Lambo Dam on Flores Island, has yet to be finished because of a land dispute with Indigenous communities in Nagekeo district.
- Research shows that much of Indonesia, particularly in the east, face increasing water stress due to climate change, as well as drought spikes brought on by the positive Indian Ocean dipole and El Niño patterns.

A Ramsar site in Bangladesh fast loses its fish diversity amid government inaction (Nov 19 2024)
- Tanguar Haor, Bangladesh’s second largest Ramsar site and one of the country’s most important habitats of breeding fish, has been losing its fish diversity.
- A recent study found that the number of available fish species is now below 100 while, just two decades ago, the figure was recorded to be 141.
- Experts blame anthropogenic factors, including overfishing and habitat destruction, as the causes of declining diversity.
- However, authorities are ignoring the rising urgency for conservation and are instead celebrating the “increased fish production in the wetland.”

Organizations tackle droughts, floods in Brazil by planting forests (Nov 18 2024)
- Many areas of Brazil have been hit with severe droughts and floods in recent years; scientists say climate change is increasing the incidence of extreme weather events.
- Forests protect against erosion and pollution and help store water in soil and aquifers, buoying water security.
- Organizations across the country are leading efforts to reforest cleared areas — particularly along rivers and other water sources —to mitigate the damaging effects of droughts, floods and other effects of climate change, as well as safeguard and improve habitat for wildlife.
- Experts and stakeholders say broader support is needed at the federal level, while a representative of Brazil’s Ministry of Environment and Climate Change says the government is rolling out conservation plans of its own.

Easy to catch, yet little known: Meet the Chinese mountain cat (Nov 18 2024)
- The Chinese mountain cat (Felis bieti) is a little-known felid found only on the eastern edge of the Qinghai-Tibet Plateau, in northwestern China.
- The species was first photographed in the wild in 2007, and until recently, very little has been known about its distribution and basic ecology.
- Researchers collected vital data on an active Chinese mountain cat den in 2018, while a recent study in Menyuan county, Qinghai province, managed to GPS-collar Chinese mountain cats for the first time.
- Recent genetic research highlights the growing threat posed by hybridization with domestic cats.