Rainforest loss is fuelling a tsunami of tropical species extinctions. However, not all is doom and gloom. A new study, conducted in the Brazilian Amazon, suggests that ecological cataclysms prompted by the fragmentation of the forest can be reverted by the regeneration of secondary forests, offering a beacon of hope for tropical forest biodiversity across the world.

Credit: Mark Moffett/ Minden Pictures/National Geographic Stock

The international team of researchers found that species strongly associated with primary forest were heavily depleted after 15 years of man-made disruption including the burning and clearing of forest stands,

However, 30 years down the line, and with the regeneration of secondary regrowth, many of the species that had abandoned the area had made a comeback.

"If you compare the time periods, it is apparent that taking a long-term view is paramount to uncovering the complexity of biodiversity in human-modified landscapes," said senior researcher Dr. Christoph Meyer, lecturer in global ecology and conservation at the University of Salford.

The study, published in Nature: Scientific Reports, measured the impacts of forest break-up of 50 species of bat (approx. 6,000 animals).

Bats comprise roughly one fifth of all mammal species and display wide variation in foraging behaviour and habitat use, making them an excellent model group for the research.

"The responses exhibited by bats offer important insights into the responses of other taxonomic groups." says Ricardo Rocha, lead author of the study from the University of Lisbon.

"The recovery that we have documented mirrors the patterns observed for beetle and bird communities within the Amazon.

"These parallel trends reinforce the idea that the benefits of forest regeneration are widespread, and suggest that habitat restoration can ameliorate some of the harm inflicted by humans on tropical wildlife", he adds.

The results of the current study contrast with the catastrophic faunal declines observed during a similar time window in rodent communities in the 'forest islands' of the Chiew Larn reservoir in Thailand.

"The recovery observed at the Amazon was mostly due to the recolonization of previously deforested areas and forest fragments by old-growth specialist bats. This recolonization is likely attributable to an increased diversity and abundance of food resources in areas now occupied by secondary forest, fulfilling the energetic requirements of a larger set of species", explains Rocha.

However, the short-term nature of most studies has substantially impaired the capacity of researchers to properly capture the intricate time-related complexities associated with the effects of forest fragmentation on wildlife.

Source: University of Salford [February 28, 2018]

Fields, streets and cities, but also forests planted in rank and file, and dead straight rivers: humans shape nature to better suit their purposes, and not only since the onset of industrialization. Such influences are well documented in the Amazonian rainforest. On the other hand, the influence of humans was debated in Central Africa where major interventions seem to have occurred there 2,600 years ago: Potsdam geoscientist Yannick Garcin and his team have published a report on their findings in the Proceedings of the National Academy of Sciences. The research team examined lake sediments in southern Cameroon to solve the riddle of the "rainforest crisis." They found that the drastic transformation of the rainforest ecosystem at this time wasn't a result of climatic change, it was humankind.

Farming activities in North-West Region of Cameroon [Credit: Better World Cameroon]

More than 20 years ago, the analysis of lake sediments from Lake Barombi in southern Cameroon showed that older sediment layers mainly contained tree pollen reflecting a dense forested environment. In contrast, the newer sediments contained a significant proportion of savannah pollen: the dense primitive forest quickly transformed into savannahs around 2,600 years ago, followed by an equally abrupt recovery of the forest approximately 600 years later. For a long time, the most probable cause of this sudden change, dubbed the "rainforest crisis," was thought to be climate change brought about by a decrease in precipitation amount and increase in precipitation seasonality. Despite some controversy, the origin of the rainforest crisis was thought to be settled.

High volumes of precipitation in the region (over 3,000 mm annually) have ensured that the lake has not dried out over the millenia. This heavy rainfall has created large volumes of sediment, which are then washed into the lake. These circumstances make it possible to perform sediment analyses with the utmost precision [Credit: B. Brademann/GFZ]

Yet Garcin, a postdoctoral researcher at the University of Potsdam, and his international team of scientists from UP, CEREGE, IRD, ENS Lyon, GFZ, MARUM, AMU, AWI, and from Cameroon suspected that other causes could have led to the ecosystem's transformation. By reconstructing both vegetation and climate change independently -- through stable isotope analysis of plant waxes, molecular fossils preserved in the sediment -- the team confirmed that there was a large change in vegetation during the rainforest crisis, but indicated that this was not accompanied by a change in precipitation.

"The rainforest crisis is proven, but it cannot be explained by a climate change," says Garcin. "In fact, in over 460 archaeological finds in the region, we have found indications that humans triggered these changes in the ecosystem." Archaeological remains older than 3,000 years are rare in Central Africa. Around 2,600 years ago, coincident with the rainforest crisis, the number of sites increased significantly, suggesting a rapid human population growth -- probably related to the expansion of the Bantu-speaking peoples in Central Africa. This period also saw the emergence of pearl millet cultivation, oil palm use, and iron metallurgy in the region.

This floating platform can be completely taken apart and transported overseas. The platform enabled the collection of sediment samples in the approximately 100-meter-deep Lake Barombi, which were then analyzed in the laboratory [Credit: Y. Garcin/University of Potsdam]

"The combination of regional archaeological data and our results from the sediments of Lake Barombi shows convincingly that humans strongly impacted the tropical forests of Central Africa thousands of years ago, and left detectable anthropogenic footprints in geological archives," says Dirk Sachse at the Helmholtz Center Potsdam -- Research Center for Geosciences (GFZ). Sachse was one of the major contributors to the development of the method for analyzing plant wax molecular fossils (termed biomarkers).

"We are therefore convinced that it was not climate change that caused the rainforest crisis 2,600 years ago, but it was the growing populations that settled in the region and needed to clear the forest for exploiting arable land," says Garcin. "We are currently observing a similar process underway in many parts of Africa, South America, and Asia." But the work of Garcin and his team also shows that nature has powerful regenerative abilities. When anthropogenic pressure decreased 2,000 years ago forest ecosystems reconstituted, but not necessarily as before: as in the Amazonian rainforest, field studies show that the presence of certain species is very often related to past human activity.

Source: GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre [February 26, 2018]

The tropical rainforests of Central and South America are home to the largest diversity of plants on this planet. Nowhere else are there quite so many different plant species in one place. However, the entire region is increasingly threatened by human activity, which is why researchers are stepping up their efforts to record this astonishing biodiversity and find out how it developed. In a project undertaken by Johannes Gutenberg University Mainz (JGU) in collaboration with Dutch research institutions, the causes of this plant diversity were investigated by studying two closely related groups of trees of the Annonaceae family.

Cremastosperma brevipes, French Guiana [Credit: Paul J. M. Maas]

The researchers identified three relevant factors: the formation of the Andes mountain range, the disappearance due to natural causes of the extensive Pebas wetlands system that once existed in the Amazon region, and the formation of a land bridge between Central and South America in the form of the Panama Isthmus.

Cremastosperma and Mosannona are two genera of the Annonaceae or custard apple family the habitat of which is neotropical rainforests, where they extend from the lowlands up to elevations of 2,000 meters. They are primarily found in the Andes region of South America, but also as far north as Central America.

Mosannona costaricensis, Costa Rica [Credit: Reinaldo Aguilar]

The team of botanists led by Dr. Michael Pirie, who joined JGU as a researcher in 2013, looked at the distributions of the various species of both genera and their phylogenetic history in order to determine the influence of the geological upheavals on the continent.

For this purpose they compiled a time-calibrated phylogenetic tree based on DNA data, using the so-called molecular clock technique which is calibrated using the ages of the available fossils. In total, they analyzed 11 species of the genus Mosannona and 24 species of the genus Cremastosperma.

Formation of the Andes, the Isthmus of Panama, and the drying-out of the Pebas wetland system all promoted diversification

The research has produced a biogeographical scenario that confirms in this context the significance of the geological history of north-western South America during the late Miocene and early Pliocene periods about 5 to 10 million years ago.

Cremastosperma yamayakatense, Peru [Credit: Michael Pirie]

"We have actually discovered that the diversification of these two plant genera took place in parallel with major geological events, namely the formation of the Andes, the drying-out of the Pebas system, and the development of a land bridge to Central America," explained Pirie. Cremastosperma species, for example, were able to spread into what is today the Amazon basin and diversify, once the wetlands had silted up due to the deposition of material from the rising Andes.

One way in which diversification can be stimulated is by migration into a new ecosystem while another is adaptation to new conditions. "Natural changes over longer periods provide plants with a chance to adapt," added Pirie. On the other hand, rapid changes, such as those that have occurred in the recent past, do not give plants sufficient time to evolve.

Cremastosperma leiophyllum, Bolivia [Credit: Lars W. Chatrou]

While the development of the two genera in line with geological conditions could be said to be more or less as might be expected, the biologists did find one clear difference between them. Although their distribution patterns mostly overlap, Cremastosperma species and Mosannona species to some extent dispersed along differing routes. In the case of Cremastosperma, colonization of an area in what is now Guyana began from north-western South America at a time before the last parts of the Andes developed and could form a barrier. Mosannona, on the other hand, began to spread here at a far later date from its base in the Amazon basin.

Taxonomic update to include five new species

Dr. Michael Pirie will be continuing his research work in 2018 with the aid of a grant from the Heisenberg Program of the German Research Foundation (DFG). This will also involve publication of an extensive monograph in which a total of 34 Cremastosperma species will be described, including five new species that Pirie and his colleagues have recently discovered.

The study is published on Royal Society Open Science.

Source: Universitat Mainz [Febraury 26, 2018]

When it comes to spreading their seeds, many trees in the rainforest rely on animals, clinging to their fur or hitching a ride within their digestive tract. As the seeds are spread around, the plants' prospects for survival and germination are increased.

Researchers from UConn and the San Diego Zoo Institute for Conservation and Research examined how the overhunting of seed dispersing animals is changing tree communities in Western Amazonia, such as those in Manu National Park [Credit: Varun Swamy]

But in many tropical forests, over-hunting is diminishing the populations of those animals, and, as a result, changing the make-up of the forests themselves.

A new study of the Amazon rainforest by researchers at UConn and the San Diego Zoo Institute for Conservation and Research, published in the Journal of Ecology, examines what happens to plants if their seed dispersers are no longer present. They found that theoretical models predicting a dire impact on plant communities and huge decreases in the amount of carbon stored in tropical forests are not supported by the facts. Instead, the effects on the ecosystem are less straightforward and less immediately devastating.

"Yes, there is a negative effect, but there isn't 100 percent mortality," says Robert Bagchi, assistant professor of ecology and evolutionary biology at UConn. "The story is more complex and much more subtle."

Whereas the models used in the previous studies did not use actual data on items such as mortality, survival, growth, and spatial distribution, Bagchi and his fellow researchers explored the question in greater detail, using a statistical technique they recently developed with extensive data collected on tree communities in the 80,000 km2 Madre de Dios river basin, located in the southeastern corner of Peru's Amazon rainforest.

In Western Amazonia, as many as two-thirds of all tree species rely on native, fruit-eating mammals such as spider monkeys and tapirs, or birds like guans, trumpeters and toucans, who are able to travel fairly large distances and carry any ingested seeds far from their parent trees.

Dispersal is advantageous for seeds because spreading out will give seedlings an edge over specialized natural predators who might otherwise wipe out aggregations of undispersed plants.

"The idea is that the seeds escape," says Bagchi. "A lot of pathogens and insects are quite specific about which plants they will eat, and if there is no dispersal and their desired plants are densely aggregated, those plants will be clobbered."

In tropical rain forests, as many as two-thirds of all tree species rely on native, fruit-eating mammals such as capuchin monkeys who are able to travel fairly large distances and carry any ingested seeds far from their parent trees. What happens to the forests when these seed dispersing animals are over hunted? [Credit: Varun Swamy]

In addition, the tree species dispersed by these animals also store the most carbon.

Unfortunately, the large-bodied animals and birds are the favorite quarry of hunters for bush meat.

The researchers examined tree communities in the tropical rain forests of Western Amazonia, in terms of forest spatial organization and carbon storage capacity. They did find that tree communities in hunted forests appear to be undergoing a reorganization, where saplings of species that rely on large hunted animals for dispersal are now growing closer to each other and forming denser clumps in hunted forests.

But the long-term implications for biodiversity and the biomass of forests are not yet clear. And the expectation that without their dispersers, seeds of these plant species will land in the "kill zone" of insects and diseases under their parents and be replaced by other species that store less carbon, culminating in huge decreases in the amount of carbon stored in tropical forests, has not materialized.

A number of factors could be contributing to the reason that previous theories are not proving true, Bagchi says.

Smaller seed dispersers that often increase when their larger competitors are hunted out may be compensating. Additionally, the trees analyzed in the study were already at least 10-15 years old, so follow-up studies will instead focus on the early lives of these trees, starting at the germination stage.

Questions the researchers hope to pursue include, What are the survival rates of undispersed seeds in hunted forests? Is limited dispersal by smaller animals enough to ensure a seed's survival? How do these stages fit together -- does high survival at a later stage compensate for low survival of undispersed seeds?

"We can't simplify the process to just a linear one," says Bagchi. "We need data following the whole process, from seed dispersal to trees growing into adults."

Bagchi also cautions that although these findings are somewhat hopeful in light of previous modeling studies, tropical forests in South America, Asia, and Africa are becoming ever more stripped of their diversity of flora and fauna, fundamentally changing the structure of these complex systems.

Source: University of Connecticut [February 15, 2018]

Tropical forests around the world play a key role in the global carbon cycle and harbour more than half of the species worldwide. However, increases in land use during the past decades caused unprecedented losses of tropical forest. Scientists at the Helmholtz Centre for Environmental Research (UFZ) have adapted a method from physics to mathematically describe the fragmentation of tropical forests. In the scientific journal Nature, they explain how this allows to model and understand the fragmentation of forests on a global scale. They found that forest fragmentation in all three continents is close to a critical point beyond which fragment number will strongly increase. This will have severe consequences for biodiversity and carbon storage.

The aerial photo shows forest fragments of the Brazilian Atlantic rainforest in Northeastern Brazil (Mata Atlantica), surrounded by sugar cane plantations [Credit: Mateus Dantas de Paula]

In order to analyse global patterns of forest fragmentation, a UFZ research group led by Prof. Andreas Huth used remote sensing data that quantify forest cover in the tropics in an extremely high resolution of 30 meters, resulting in more than 130 million forest fragments. To their surprise they found that the fragment sizes followed on all three continents similar frequency distributions. For example, the number of forest fragments smaller than 10,000 hectares is rather similar in all three regions: 11.2 percent in Central and South America, 9.9 percent in Africa and 9.2 percent in Southeast Asia. "This is surprising because land use noticeably differs from continent to continent," says Dr. Franziska Taubert, mathematician in Huth's team and first author of the study. For instance, very large forest areas are transformed into agricultural land in the Amazon region. By contrast, in the forests of Southeast Asia, often economically attractive tree species are taken from the forest.

When searching for explanations for the identical fragmentation patterns, the UFZ modellers found their answer in physics. "The fragment size distribution follows a power law with almost identical exponents on all three continents," says biophysicist Andreas Huth. Such power laws are known from other natural phenomena such as forest fires, landslides and earthquakes. The breakthrough of their study is the ability to derive the observed power laws from percolation theory. "This theory states that in a certain phase of deforestation the forest landscape exhibits fractal, self-similar structures, i.e. structures that can be found again and again on different levels," explains Huth. "In physics, this is also referred to as the critical point or phase transition, which for example also occurs during the transition of water from a liquid to gaseous state," added co-author Dr. Thorsten Wiegand from UFZ. A particularly fascinating aspect of the percolation theory is that this universal size distribution is, at the critical point, independent of the small-scale mechanisms that led to fragmentation. This explains why all three continents show similar large-scale fragmentation patterns.

The UFZ team compared the remote sensing data of the three topical regions with several predictions of percolation theory. In support of their hypothesis they found agreement not only for the fragment size distribution, but also for two other important indicators - the fractal dimension and the length distribution of fragment edges. "This physical theory allows us to describe deforestation processes in the tropics," concludes Dr. Rico Fischer, co-author of the study. And that's not all: this approach can also be used to predict how fragmentation of tropical forests will advance over the next decades. "Particularly near the critical point, dramatic effects are to be expected even in the case of relatively minor deforestation," adds Taubert.

Using scenarios that assume different clearing and reforestation rates, the scientists modelled how many forest fragments can be expected by 2050. For example, if deforestation continues in the Central and South American tropics at the current rate, the number of fragments will increase 33-fold and their mean size will decrease from 17 ha to 0.25 ha. The fragmentation trend can only be stopped by slowing down deforestation and reforesting more areas than deforesting, which currently is a rather unlikely option. Future satellite missions, such as Tandem-L, are of great importance for the timely and reliable detection of these trends.

Advanced fragmentation of tropical forests will have severe consequences for biodiversity and carbon storage. On the one hand, biodiversity suffers because numerous rare animal species depend on large forest patches. For example, the jaguar needs around 10,000 hectares of contiguous forest to survive. On the other hand, the increasing fragmentation of forests also has a negative impact on climate. A UFZ team of scientists led by Andreas Huth described in Nature Communications in spring of last year that fragmentation of once connected tropical forest areas could increase carbon emissions worldwide by another third, as many trees die and less carbon dioxide is stored in the edge of forest fragments.

Source: Helmholtz-Centre for Environmental Research - UfZ [February 14, 2018]

More than 100 researchers have collaborated to classify the world's tropical forests according to their evolutionary history, a process that will help researchers predict the resilience or susceptibility of different forests to global environmental changes.

The Amazon Rainforest [Credit: © Stéphane Bidouze/Fotolia]

The results, culled from almost 1 million different tree samples from 15,000 tree species, have uncovered a shared ancestry between tropical forests thousands of miles apart and previously believed to be unrelated. Published this week in the Proceedings of the National Academy of Sciences, the study describes an international, grassroots effort to collect and analyze data from more than 400 geographic coordinates across the tropics, a region that comprises 40 percent of the Earth's surface.

The study was led by Ferry Slik, an associate professor at the Universiti Brunei Darussalam in Brunei. Janet Franklin, a distinguished professor of biogeography at the University of California, Riverside, coordinated the interpretation and reporting of the data, which is publicly available as an open access article.

Franklin said the new classification scheme's value comes from the inclusion of ancestral information about the tree samples (gleaned from DNA analyses), rather than the "snapshot" of tree biodiversity that is obtained from recording a plant's species.

A phylogenic classification of the world's tropical forests revealed five major regions [Credit: UC Riverside]

"When ecologists study biodiversity, they look at the present day by identifying the range of species in a particular forest. However, without going deeper into a plant's history by looking at its family tree, each species is considered separate and unrelated," Franklin said. "By adding the evolutionary relationships between species, however, we suddenly have a measure of how similar species are to each other. This means that we were able to do a much more detailed and realistic comparison between forest sites than previously possible."

The study revealed five major tropical forest regions: Indo-Pacific, Subtropical, African, American, and Dry Forests, which are found at the boundaries between tropical and dry climates.

The study also showed the evolutionary relationships between the forests. One surprising finding was that tropical forests in Africa and South America are closely related, with most of the differences between them occurring within the last 100 million years.

UC Riverside's Janet Franklin conducting field work in a tropical dry forest in The Bahamas [Credit: UC Riverside]

"An African tropical forest is evolutionally more similar to tropical forests in the New World than to forests in the Indo-Pacific," Franklin said. "While this was somewhat unexpected, it likely reflects the breaking apart of South America and Africa resulting in the formation of the Atlantic Ocean that started approximately 140 million years ago."

Researchers also found that related subtropical forests exist in two distinct regions: East Asia and Central/South America. "These regions share the same temperate climate and, even though they are not geographically close, their forests share common ancestors, which is a bit of a mystery," Franklin said. "However, it may be that we are actually looking at remnants of the once extensive tropical forests that ranged from North America all the way to Europe and Asia. When Earth's climate cooled down these forests mostly disappeared, but parts seem to have survived in Asia and America."

The researchers hope an understanding of the diversity and composition of the tropical forests will help them anticipate region-specific responses to global environmental change.

"Different forests may be more vulnerable or resilient to climate change and deforestation, so if we understand the similarities and differences between forests it will help inform conservation efforts," Franklin said.

Source: University of California - Riverside [February 05, 2018]

Tropical forests all over the world are at risk. Two of the main threats are the deforestation for arable land and climate change. Scientists from the Technical University of Munich (TUM) and the Thünen-Institute compared the losses due to deforestation with those that would result in extreme climate change scenarios in Ecuador. Although global warming is likely to change the distribution of species, deforestation will result in the loss of more dry forests than predicted by climate change damage.

Most of Ecuador's dry forests are located in the southwest of the country, in the Tumbes-Choco-Magdalena region [Credit: P. Hildebrandt/TUM]

A large proportion of Ecuador's rare dry forests are located in the southwest of the country, in the Tumbes-Chocó-Magdalena region. These forests provide not only wood and non-wood products, but also important ecosystem services that regulate the water balance and protect the soil from erosion. However, the area suffers a high loss of habitat due to deforestation for more arable and pasture land. This exacerbates the negative effects of climate change, such as temperature increases.

In cooperation with scientists from the Thünen-Institut and the Ecuadorian Universidad Técnica Particular de Loja, a team from TUM compared the predicted loss of area of tree species caused by deforestation on the one hand and by predicted forest losses in an extreme climate change scenario on the other. We have evaluated 660 data sets on the occurrence of 17 characteristic species of dry forests in the south of Ecuador," explain first author Carlos Manchego and Patrick Hildebrandt from the Chair of Silviculture at TUM - "in order to estimate both potential threats, we have compared the forecast annual rates of losses. However, it is important that the results are not transferable to other tree species in other regions."

Losses from conversions in the period 2008 to 2014, especially for agricultural and pasture land, averaged 71 square kilometres per year for all species in the study area. The predicted loss of species area in the climate change scenario was only 21 square kilometres per year.

Recommendations for more effective forest protection and sustainable land use

One unexpected outcome was the different displacement directions of tree species due to climate change. While some species migrate to the north, other species find their future distribution focus more to the south. This leads to a trend towards mixing tree species with hitherto unknown effects on the functionality and stability of future forest communities," says Hildebrandt. "At the same time, grubbing-up starts in the higher altitudes, because it's easier to grow something like corn there."

According to Hildebrandt, it is important for efficient planning, the implementation of protective measures and sustainable land use to prioritise the measures according to such threats and weak points. A distinction must be made between the potential threats posed by climate change and deforestation. With the study PLOS One we wanted to provide a scientific frame of reference to identify the lesser evil and make targeted recommendations".

However, regardless of the conservation strategy, these objectives required the participation of both private landowners and local communities.

Source: Technical University of Munich [February 02, 2018]

Imagine your hometown or city's entire population had to live on just one tenth of the land it used to—essentials like food and shelter would quickly go scarce, and it'd be just about impossible for the populace to sustain itself. This, in broad strokes, is what's happening to the flora and fauna of the Atlantic Forest, the second most biodiverse forest system in South America (after the Amazon).

Gracilinanus agilis, a marsupial species whose data is represented in this study [Credit: (c) Noe de la Sancha, The Field Museum]

Spanning the Atlantic coast of Brazil into eastern Paraguay and Argentina, the Atlantic Forest once covered roughly 463,000 square miles of habitat. Today, only 8-12 percent of this original habitat space remains. Deforestation poses a substantial threat to the region's native plant and animal species, and for mammals in particular, habitat loss is the main driver of extinction.

This, of course, is a troubling reality for scientists studying the Atlantic Forest's mammals. Worried that species are disappearing at faster rates than they can be studied, 96 of these scientists took collective action and wrote a paper published in Ecology cataloguing traits such as body mass, reproductive attributes, and tail length in mammals native to the Atlantic Forest.

To give a sense of the project's scale: the 96 co-authors of this paper compiled trait information on 39,850 individuals from 279 different mammal species and 388 separate populations.

"This is the first comprehensive dataset of this forest system's mammalian trait data," said Noe de la Sancha, co-author and research associate at the Field Museum in Chicago. "We wanted to create a resource so that scientists wouldn't have to dig through every natural history museum in the country to find these data. It's a stepping stone for future research, putting that out for everybody to use—it's a really big change in science."

Rodent specimens at The Field Museum representative of the kinds of specimens de la Sancha contributed to this study [Credit: (c) The Field Museum]

De la Sancha explained that when zoologists rely solely on their own data, they're limited in what questions they're able to ask and answer. An example: de la Sancha's research focuses specifically on rodents and marsupials in eastern Paraguay. He's done years of fieldwork, collecting thousands of specimens and authoring dozens of papers along the way. Still, if he wanted to figure out how the small mammals he studies developed their traits over thousands of years, or how they ended up in eastern Paraguay in the first place, he'd need to look for more evidence elsewhere—likely from natural history museums in the U.S. or abroad. This process can be time-consuming and costly.

"For this paper, everyone threw their data into this large, extensive collective," de la Sancha said. "We're putting puzzle pieces together. Having more data available, we can start to ask more interesting questions—questions of ecology and modeling that have more serious impact than cursory descriptors."

Fernando Goncalves, lead author and graduate student at Universidade Estadual Paulista (UNESP) - Sao Paulo State University in Sao Paulo, Brazil, agreed with de la Sancha that this paper expands possibilities for zoological and ecological research.

"Ninety-six authors accepted the challenge to go back to their field notes and send as much information on mammal morphological traits as they could," Goncalves said. "And thanks to them, we'll be able to provide raw data for ecological and evolutionary studies for researchers all over the world."

Gracilinanus agilis, a South American oppossum whose species was represented in this study [Credit: (c) Noe de la Sancha, The Field Museum]

This paper is a critical—and urgent—step in the right direction, providing scientists with an expansive research toolkit as Atlantic Forest habitats continue to shrink. In turn, these scientists hope to draw attention to the Atlantic Forest as a region to protect, so that they can continue their studies and learn more about the impact of factors like climate change and human activity on these mammal species.

"There's still a great deal we don't know about our biodiversity—and as a consequence, we don't know what we're losing," de la Sancha emphasized. He hopes this paper, on top of serving as a resource for fellow scientists, highlights the importance of mammal species to the Atlantic Forest's ecosystem. He's particularly passionate about small mammals' role in this ecosystem.

"These are the dudes that drive the world," de la Sancha said, pointing to a shelf of rat specimen in his lab. "It's rodents. It's not primates, lions, bears. Rodents are the most important group of mammals, the base of most food chains. They disperse seeds for trees and spores for fungi. They also act as vectors for various kinds of diseases that might affect us. And the best way to target those diseases is studying the rats affected and why."

De la Sancha sees his contributions to this paper as "putting my grain of sand on the beach, so to speak." And his research, along with the other 95 grains of sand that comprise this paper, could make a real, tangible impact on how we study—and care for—the Atlantic Forest.

"Hopefully if these types of papers start getting attention, people will start to value what they have in their backyards," de la Sancha said. "This paper highlights the importance of this forest system, and that could potentially get locals pumped about conserving it."

Source: Field Museum [February 01, 2018]

Tropical forests span a huge area, harbor a wide diversity of species, and are important to water and nutrient cycling on a planet scale. But in ancient Amazonia, over 500 years ago, clearing tropical forests was a way of survival to provide land for families to farm and villages to prosper. Researchers at the University of New Hampshire used high-tech tools to more precisely view where these cleared sites were and how much lasting impact they had on the rainforest in the Amazon Basin in South America.

Map developed using satellite imagery and spatial modeling showing estimated past human impact  on the Amazonian forest [Credit: Michael Palace/UNH]

"One of the key mysteries in this area of the world is that no one knows how many people lived in Amazonia before European contact," said Michael Palace, an associate professor in the Earth Sciences Department and Earth Systems Research Center at UNH. "Once the Europeans arrived, indigenous populations were devastated due to disease, slavery and displacement so it's often hard to determine lasting impact. It is important to understand the resilience or fragility of these forests to past human disturbance, which allows for appropriate planning on the use of natural resources."

One of the few indicators of human settlements are the terra preta, or Amazonian Dark Earths (ADEs). These are black, human-made soils that are enriched by materials left behind from past societies, pottery remnants, charcoal and other artifacts frequently associated with human origin. There is very little rock and metal in that part of the world (a former ocean bottom), and wood, bone and other organic materials decay quickly in the humid tropics.

In their study, recently published in the journal Ecosphere, the researchers used imagery from NASA's terra satellite, MODIS, and geospatial modeling to predict the ADE probability across six million square kilometers of the Amazonia. They found that biomass (primarily weight of trees in forests), tree height, and tree cover were all lower at ADE sites than adjacent random non-ADE locations. The ADE sites were also more susceptible to drought.

Indigenous people most likely used slash-and-burn techniques to clear the forests so the ADE sites may have been pre-selected due to the propensity for drought or intensity of dry seasons. Researchers also observed differences in spectral properties (reflective light) between ADE and non-ADE sites that are likely driven by forest structure and tree species, indicating that remnant forests are still showing impacts from past human settlement patterns.

Researchers further explain that the high spatial heterogeneity in ADE sites across the Amazon suggests that pre-Columbian occupation by indigenous people was complex and varied substantially across this ecologically diverse region. But they speculate that because of their proximity to the rivers, ADEs may have become areas of interest for other groups to settle and reoccupy, further impacting the forests and vegetation in the ADE areas.

Source: University of New Hampshire [January 18, 2018]

In August 2017, the Bolivian government passed a contentious law that paved the way for construction of a new 190-mile road cutting through one of the country's most iconic and biodiverse protected rainforests. But a report in Current Biology shows that the Isiboro-Sécure National Park and Indigenous Territory (or TIPNIS, as the area is commonly known) has been subject to alarming levels of deforestation within its borders for many years, a reality that is too often overlooked.

Photograph of an Amazonian rainforest [Credit: Oriol Massana and Adrià López-Baucells]

TIPNIS, which is also the ancestral homeland of four lowland indigenous groups, lost more than 46,000 hectares of forest from 2000 to 2014, according to the report. (To put that in perspective, one hectare is about the size of a standard sports field.) The researchers say they hope the findings will help to give public debate on the matter a stronger foundation based on the best available evidence.

"While many discuss the potential impacts that the planned road could have in the future, very little is spoken about current ecological impacts in the area," says Álvaro Fernández-Llamazares from the University of Helsinki, Finland. "Our analyses show that TIPNIS is already facing rampant levels of deforestation."

Tamandua tetradactyla [Credit: Oriol Massana & Adrià López-Baucells]

It is well established that roads in tropical forests frequently lead to additional habitat conversion. In the case of TIPNIS, the researchers, including Mónica Moraes at Bolivia's Universidad Mayor de San Andrés, report that more than 58 percent of deforestation is found within five kilometers of existing roads. This trend suggests that the planned road will only "magnify the current scale and pace of deforestation in TIPNIS."

"We were surprised to discover that one of Bolivia's most iconic national parks could be facing such alarming levels of deforestation," Moraes says. That TIPNIS has lost more than 46,000 hectares of forest since the year 2000 "is simply unbelievable, considering that the park is not only one of the main biodiversity hotspots in Bolivia, but also one of the most biodiverse regions on Earth."

Photograph of the disputed road [Credit: Sara Fraixedas]

She notes that the area harbors many plant species that do not live anywhere else. It is also home to emblematic wildlife species, such as the jaguar, marsh deer, and giant otter.

While food security is often noted as justification for road building, the researchers add that most of the deforestation to date in TIPNIS is associated with cultivation of coca, not food crops. With expanded coca cultivation and new incentives for oil and gas exploration throughout Bolivia, they say that downgrading the legal protection of TIPNIS will most likely spur even greater biodiversity losses. The authors therefore call on Bolivia's government to revisit the road plans.

"Bolivian delegations have been very active in climate change negotiations and have vehemently advocated for the codification of the rights of Mother Earth in several international policy frameworks," Fernández-Llamazares says. "The road would most likely open a Pandora's box of environmental problems that, as a signatory of the Convention on Biological Diversity, Bolivia will surely struggle with."

Source: Cell Press [January 08, 2018]