Deforestation and degradation are not the same thing. While the first is readily detected from space by satellite, the second is a more discreet villain: small fires, illegal logging, fragmentation and hunting are silently consuming the Amazon Rainforest.

Degraded forest in the Tapajós National Forest, Pará state, Brazil. / Photo: Flavio Forner

Unreported fires

Wildfires in the Amazon have dangerous accomplices: crime, lack of economic alternatives amongst some of the poorest members of society, legislative inefficiencies and even climate change. Preventative measures are still insufficient and the story of wildfire in the Amazon is largely untold.

Recently burned forest in the northwest region of Pará state. / Photo: Flavio Forner

The timber problem

Predatory logging in the Amazon is a long term threat to the survival of the forest. Sustainable management has brought new perspectives to this old struggle, but even today 90% of timber logging takes place outside the law.

A logging patio near Nova Ubiratã in Mato Grosso state. / Photo: Bruno Kelly

Birds still sing

Forest disturbance affects species of animals differently, among them the thousands of bird species from Amazonia. In degraded forests, the loss of bird biodiversity can be glaring.

A couple of Scarlet Macaws in the Carajás National Forest, Parauapebas, Pará state. / Photo: João Marcos Rosa




Alert to the silent agony of the rainforest, a team of Brazilian and foreign scientists has created something unprecedented and decisive for the future of tropical forests around the world: A parameter to evaluate degradation.

Contributing factors to degradation in the Brazilian Amazon Rainforest

Fire    Logging    Hunting    Fragmentation

In games of word association, the term ‘deforestation’ has become inextricably linked to the word ‘Amazonia’. Those who care about this vast forest closely follow the variation in deforestation rates, celebrate when policies to combat the illegal clearance of forests are shown to be effective and worry whenever there is an indication of an about-face in rates of loss. But that’s only part of the story. An international team of have monitored the health of the forest in the state of Pará since 2009. According to them, dealing with deforestation alone may only resolve around half of the challenges facing the biodiversity of the planet’s most diverse ecosystem. That is because there is a stealthier, more persistent, and often ignored villain: forest degradation.

Forest degradation is the end result of a set of disturbances that occur due to human impacts on the environment. Although much of the forest may remain standing, these disturbances leave biodiversity impoverished and ecological function impaired. Deforestation, often referred to as clearcutting, is the total loss of forest and its replacement with pasture, monocultures, or even eventual abandonment. Of the two, degradation is much harder to detect. The untrained eye may see an ecosystem that resembles an intact forest: there are trees after all. But looks can be deceiving, and help make degradation more difficult to quantify and the policies to combat it harder to argue for. Yet a recent scientific study has revealed that degradation, far from being a minor problem, is slowly silencing much of the life of Amazonia.

The disturbances to which tropical forests are exposed are widely known and have affected the Amazon for decades. The worst culprits are the predatory extraction of wood, wild fires, the subdivision of forest into smaller and smaller patches (fragmentation) as well as the hunting of animal species. “These results should serve as a warning to the global community,” explains Jos Barlow, an Ecologist at Lancaster University (UK) and lead author of the article ‘Anthropogenic disturbance in tropical forests can double biodiversity loss from deforestation’, published in June 2016 in the journal Nature, one of the foremost scientific journals in the world.

Forest Degradation in Pará State

Click on any polygon to zoom in and access a detailed analysis of the conservation value lost due to degradation in each area. Double-click the same polygon to zoom out. The polygons represent the average size of the studied areas, which in the original research ranged between 20 and 50 km². The lighter polygons near urban centers indicate regions where there is no more forest cover, therefore the rate of degradation is low.

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Until now, the combined effect of human disturbance (logging, fire, hunting, fragmentation) on the conservation value of primary forests was unknown. RAS researchers filled this knowledge gap using a large dataset of plants, birds and beetles (1,538, 460 and 156 species, respectively), collected in 36 watersheds in the regions of Santarém and Paragominas. By comparing the number of species found in intact forests with those in degraded areas, it was possible to establish an index – the Conservation Value Deficit (CVD). The map shows the CVD extrapolated across the entire Brazilian state of Pará. It shows the difference between the expected biodiversity in each region and the reality of what was found in the field. This data provides a very reliable picture of the effects of degradation in Pará and provides a powerful measure for evaluating degradation in tropical forests around the world. The research concluded that, outside of strictly protected areas, the effects of degradation on biodiversity in the state of Pará between 2006 and 2015 outweighed all the losses incurred through deforestation throughout the Amazon rainforest over the same period. 


Source: Barlow, J. et al. Anthropogenic disturbance in tropical forests can double biodiversity loss from deforestation, Nature 535, 144–147 (2016)

“Degradation is, first and foremost, a process,” notes Joice Ferreira, a researcher at Embrapa Eastern Amazon and co-author of the study. The opening of roads grants access to the interior of the forest, helping the exploitation of timber and the entry of illegal hunters. The predatory loggers in turn contribute to making the forest more susceptible to fire. These fires can take on epic proportions, and are difficult or impossible to control.

Deforestation and forest fragmentation is mostly driven by agricultural expansion, particularly to make way for cattle pastures. When combined, deforestation and forest disturbance can drive species extinctions and destabilize the entire ecosystem. “There is an important synergy between the factors,” summarizes Toby Gardner of the Stockholm Environment Institute (SEI). “One neighbor’s activity is not independent of the other’s. Forest degradation in the Amazon is the consequence of the activities of many people on many scales”, adds Toby, one of the coordinators of the study. “That also means that the responsibility of avoiding degradation is also shared among many people”, he concludes.

It was precisely these concerns that motivated the work of the Sustainable Amazon Network (RAS), a consortium of Brazilian and foreign research institutions coordinated by Embrapa Eastern Amazon, the Goeldi Museum in Pará, Lancaster University and the Stockholm Environment Institute (Sweden). One of the main objectives of the group was to calculate the consequence of all possible human disturbances in a forest. “There are various studies that look at each of the isolated effects, such as timber extraction and fire. The problem is that human disturbances happen all together and one leads to the other”, explains Jos Barlow, the research coordinator.

They spent two and a half years in the field. Over 100 researchers were involved, hundreds of rural properties were visited, tens of thousands of samples collected. “Imagine a small army running around in 13 pick-up trucks”, Jos recounts. “It was quite scary for those of us responsible for coordinating the work”, he laughs. The army of scientists went hunting for data on trees, birds, and beetles – all good indicators of quality of biodiversity – in the municipalities of Santarém and Paragominas, in Pará, both famous for a history of activities with high environmental impact, and also, for a more recent quest for sustainability.

It is estimated that cattle occupy 70 million hectares of Amazonia: Brazil has the largest commercial herd of cattle in the world, with 212 million animals. Cattle ranching is thus the biggest driver of deforestation in the region. / Foto: Bruno Kelly

To cover a wide gradient of environmental disturbances, the team catalogued biodiversity data collected at 381 study sites across a mosaic of different land uses. On the one hand, there were the pastures, agricultural and silvicultural crops – from annual to perennial, from the cassava plantations to the soybean, corn, and rice fields and eucalyptus plantations. On the other hand, there were the different types of forests: the region’s original ‘primary’ forests, some undisturbed and some subject to fire or exploited for timber or both. Finally, there were regenerating ‘secondary’ forests that sprouted up after land abandonment.

To catalogue the region’s megadiverse bird fauna, the team recorded all species seen or heard during surveys in each area. Plants were identified with the help of local expert botanists. They measured trees, vines, and palm trees. In all, they found 1,538 species of trees and lianas, 156 species of beetles, and 460 species of birds. “The state of Pará alone is home to 10% of the bird species on the planet, many of them endemic, meaning that they do not exist anywhere else on the planet,” says Alexander Lees, an ecologist at Manchester Metropolitan University (UK), one of the coauthors of the study and coordinators of RAS. “Our results demonstrate that they suffer the most from human impacts because they do not survive in environments with high levels of disturbance.”

The team relied on the help of local institutions, including rural unions and associations, and were supported by an extensive network of partners, including Brazil´s famed agricultural research institute, Embrapa, which is held in high regard by farmers. They knocked on the doors of both the small and large producers, from subsistence farmers to high tech agribusinesses. In total, 500 landowners opened their front gates to the researchers – a considerable feat in that these areas were until recently mired in conflicts between rural producers and environmentalists.

The combination of an extensive collection of biodiversity data from across a diverse array of landscapes allowed the team to address hitherto unanswered questions. By comparing the encounter rates of each type of species – trees, birds, and beetles – found in intact forests, with that of the same species in degraded areas, it was possible for the researchers to create a new index – the Conservation Value Deficit (CVD)- which revealed the extent and nature of the loss of biodiversity. The CVD estimates how much biodiversity is expected to be found given the amount of forest left standing and compares it with the biodiversity observed by the researchers in the field to highlight the loss in each area (see the map below).

Applying this index to Santarém and Paragominas, they concluded that the mean conservation value for birds, trees, and beetles within the forests on private property was often only 50% of that expected – in practice; this means that only half the potential value of those forests is being adequately preserved.

In Brazil, around 60% of forest remnants are located on private land. Much of these forests are partially protected by the national Forest Code, legislation that stipulates that up to 80% of the native forest in each property in the Amazon needs to be preserved as so-called ‘Legal Reserves’. In this way the Forest Code seeks to guarantee the amount of forest that, at least in appearance, is standing. There is, however, no legal instrument that focuses on the quality of that forest being maintained.

More silence, less life

Many people will look at that landscape, see a sea of green, and assume that everything is fine. What we want to show is that, in fact, these forests have lost much of their original ecological value

So what is a silent forest? To begin with, imagine a forest without some of its iconic species. With the impacts of degradation, the species that disappear first are typically the most sensitive and vulnerable. In the case of the study areas in Amazonia, the most vulnerable species were disproportionately those that had the most restricted ranges, which is a key indicator of their global conservation status. Alexander Lees explains this finding: “These species are threatened precisely because they can only live in a certain environment, and are found nowhere else in the world”.

This is the case for many birds such as the beautiful Golden Parakeet and the bizarre trumpeters. One of the latter species, the Black-winged Trumpeter Psophia obscura, is Critically Endangered and a front runner in the sad race to become the first Amazonian bird to become extinct. The jacamim as Brazilians call the trumpeter is a charismatic species, much sought after by birdwatchers and often cherished by local communities. Large, black, with long legs, and highly sociable, it’s like an ungainly forest crane. It is also endemic to the Eastern Amazon – only found in the few large remaining forest patches east of the Tocantins River. It is not only loss of its forest that is a threat, hunting is also compromising the survival of this remarkable species, which today is limited to no more than 200 individuals. Loggers working in the forest can’t get their lunch from the shops, they take what they can get, and sometimes, unfortunately that means trumpeter stew.

However, even species with no apparent economic or sentimental value to communities, such as small birds, bats and bees, may be indispensable to the ecosystem, as they guarantee the dispersal of valuable tree seeds or the pollination of agricultural crops. “We know precious little about these ecological linkages and many of them will have not even been discovered”, recalls Alexander.

The magnitude of the loss of biodiversity will depend on the health of the forest. The study surveyed everything from undisturbed forests – or as close to this as they could find – to soybean fields. In areas where the forest is regenerating after been cleared at some earlier point, it is possible to see that there is life, although many species are missing. As the forest gives way to agriculture and pasture, little remains. “This situation can be changed through measures to ensure the preservation of the legal reserves and connectivity between forest fragments, including improvements in agricultural productivity to avoid the need to clear more forest”, explains Joice Ferreira.

Not only is the conservation of biodiversity at stake. Forests provide countless services that are vital for human wellbeing and survival. These include water cycling, climate regulation, and soil protection. The relationship between healthy forests and rainfall is increasingly well established. In addition, studies by the RAS network found that forests that have suffered from logging and fire hold 40 percent less carbon than undisturbed forests. “Many people will look at that landscape, see a sea of green, and assume that everything is fine. What we want to show is that, in fact, these forests have lost much of their original ecological value”, sums up Alexander.

The Brazilian researcher, Erika Berenguer, now a tropical forest specialist at the Universities of Oxford and Lancaster, and coordinator of the study’s vegetation team, warns: “We cannot simply consider a single binary classification – whether or not there is forest. The quality of the forests affects the environmental services we depend upon, so we need to start incorporating concerns over degradation into conservation policies”, states the scientist.

Loss of Conservation Value

The map shows the state of Pará divided into areas of endemism geographic regions separated by major rivers containing their own unique fauna and flora. Amazonia is divided into eight such areas. Five form part of Pará, namely the Belém (BE), Guiana (GU), Rondônia (RO), Tapajós (TA) and Xingu (XI) areas of endemism. The map indicates the magnitude of biodiversity loss in each region and how much is anticipated to be attributable to degradation and how much was due to deforestation. The impacts of disturbances such as logging, fire and forest fragmentation were greater than the biodiversity losses caused by deforestation in three of the five areas: the Guianas, Tapajós and Rondônia. The effects of deforestation have caused most of the biodiversity loss in the Belém area of ​​endemism. Data are not available for the Island of Marajó.

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Source: Barlow, Jos. et al. Anthropogenic disturbance in tropical forests can double biodiversity loss from deforestation, Nature 535, 144–147 (2016)

According to the Brazilian space research institute (INPE), between 2007 and 2013, the area of Amazon forest that was degraded was more than 102 thousand square kilometers. This is double the area that was deforested – 55 thousand square kilometers – in the same period. Equipped with the conservation value deficit, it was possible for the researchers to compare the loss of species caused by forest disturbances with the loss of species resulting from deforestation itself. In Pará, a state that is home to a quarter of the Amazon rainforest, an area the size of South Africa, they calculated that the loss of biodiversity due only to degradation is equivalent to the loss resulting from deforestation across the entire Brazilian Amazon over the last ten years. “The widespread nature of forest degradation, combined with the severity of its effects, means that when viewed across a large area – such as the state of Pará – the impact of degradation can be even greater than that of deforestation”, warns Jos.

“Degradation must be considered as bad as deforestation, because it is the forest’s death sentence”, declares Beto Veríssimo, a senior researcher at the Institute of Man and Environment of Amazonia (Imazon, who was not involved in the study). Such a change of perspective has implications for how the Amazon is monitored and how illegal activities are dealt with.

The status of Amazonian forests is monitored from above by the Brazilian government. It is at INPE, based in São José dos Campos (in São Paulo), that the images from the satellites that regularly pass over this vast extent of forest are decoded. Different types of satellites generate various levels of information. Deforestation alerts currently rely upon the Real Time Deforestation Detection System (Deter), which uses satellites with a ground resolution of up to 30 meters. The satellites pass over the same forest area every 16 days and generating almost real-time information that is passed to environmental monitoring and enforcement teams in the field.

The technology itself is world class and continuously advancing. With this level of satellite resolution, which went into operation in 2015, replacing earlier less precise systems, it is possible to identify even when there is selective removal of timber in the forest. No other rainforest in the world has such a detailed monitoring system as the Amazon. However, one of the issues is that there are not enough staff to attend to tackle the problems that are identified on the ground.

Jair Schmidt, Coordinator of Monitoring at the Brazilian Institute of Environment and Natural Resources (Ibama), explains how decision-making works in the field. “Our main objective is to arrive in a place where deforestation is occurring at that very moment, precisely to stop it from proceeding”, he says. Clearcutting and illegal extraction of wood are the two most constant fronts of activity for Ibama in the Amazon, which is responsible for supervising all forests on public lands. In the case of what happens within private areas, under the Forest Code, the responsibility lies, in theory, with the states. However, the sates rarely fulfill this function. “If there was greater oversight by the State governments in the Amazon, our efforts to prevent environmental impacts would be much more effective”, Jair concludes.

For Beto Veríssimo, prevention is the key. “Since degradation can be a precursor of deforestation, it becomes strategic to think about how to avoid it. We must first create this culture in society”, says Beto. Among the options currently being studied is obligating landowners to restore forests on their land that have been degraded by fire. “To the extent that one becomes responsible for recovering the area – and recovery is costly – one becomes the first to try to defend it and minimize costs.”

When it comes to biodiversity, public policy also leaves much to be desired. Researchers are often critical of the strong focus on actions targeting individual species in isolation, without assessing the overall the quality of the habitats they depend upon. “In general, Brazilian strategies for biodiversity are geared towards the conservation of species that have already reached a critical point and are on the list of threatened species”, says Joice Ferreira. “But the factors that brought that species to the list are not unique and do not affect only that one species, but an entire ecosystem”, summarizes the researcher.

Jos Barlow uses the example of timber extraction to show how far we still are from properly incorporating biodiversity information into environmental planning in Amazonia. The researcher explains that, when selecting areas where wood can be extracted sustainably, the effects of cutting these trees on the lives of threatened species such as Harpy Eagles are evaluated. “But our knowledge of biodiversity is so limited that we do not even know which species would really be most important to take into account. This type of thinking hinders decision making around which areas should be prioritized for conservation “, criticizes Jos.

The forest that won’t be silenced 

While scientific evidence is not lacking, neither do we need individually tailored solutions to tackle every part of the problem of degradation. The point, says the experts, is to coordinate efforts. “Obviously, it is necessary to have specific policies aimed at timber extraction and controlling fires, but part of the problem is that the current management system for addressing these issues is disjointed. It is important not to treat the solutions in a fragmented way”, says Joice Ferreira.

From a practical point of view, there is a strong need for planning to preserve priority conservation areas. This means understanding the dynamics of the forests on a broad scale, identifying where are the areas in the best condition and where ecosystem services are most compromised due to past degradation. Such planning processes should apply equally to the selection of areas for sustainable forest management, the licensing of hydroelectric plants and mining areas, and for delimiting human occupation in areas where the forest is still in good condition.

Degraded or not, every piece of green has its relevance. Joice advises that we need to advance our scientific understanding to determine the limits of disturbance that should or should not be acceptable. Even more important is the need to ensure that the scientific evidence we already have guides decision-making about land use practices and sustainable management in the Amazon. “It reaches a point where human intervention is so intense and severe that the forest faces a greater and greater difficultly in retaining biodiversity and providing ecosystem services”, the researcher explains. “We need to know these limits and make sure they are not overstepped.” With the right push, the silenced forests can rebound back to noisy life.