Rainforest regeneration rescues bat communities in aftermath of fragmentation

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]

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Humans changed the ecosystems of Central Africa more than 2,600 years ago

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]

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Life in world's driest desert seen as sign of potential life on Mars

For the first time, researchers have seen life rebounding in the world's driest desert, demonstrating that it could also be lurking in the soils of Mars.

Hyperarid core of the Atacama Desert [Credit: Dirk Schulze-Makuch]

Led by Washington State University planetary scientist Dirk Schulze-Makuch, an international team studied the driest corner of South America's Atacama Desert, where decades pass without any rain.

Scientists have long wondered whether microbes in the soil of this hyperarid environment, the most similar place on Earth to the Martian surface, are permanent residents or merely dying vestiges of life, blown in by the weather.

In a new study published in the Proceedings of the National Academy of Sciences, Schulze-Makuch and his collaborators reveal that even the hyper-arid Atacama Desert can provide a habitable environment for microorganisms.

The researchers found that specialized bacteria are able to live in the soil, going dormant for decades, without water and then reactivating and reproducing when it rains.

"It has always fascinated me to go to the places where people don't think anything could possibly survive and discover that life has somehow found a way to make it work," Schulze-Makuch said. "Jurassic Park references aside, our research tell us that if life can persist in Earth's driest environment there is a good chance it could be hanging in there on Mars in a similar fashion."

The dry limit of life

When Schulze-Makuch and his collaborators went to the Atacama for the first time in 2015 to study how organisms survive in the soil of Earth's driest environment, the craziest of things happened. It rained.

After the extremely rare shower, the researchers detected an explosion of biological activity in the Atacama soil.

These are the surfaces of Mars and the Atacama Desert [Credit: NASA (left) / Alessandro Airo, TU Berlin (right)]

They used sterilized spoons and other delicate instrumentation to scoop soil samples from various depths and then performed genomic analyses to identify the different microbial communities that were reproducing in the samples. The researchers found several indigenous species of microbial life that had adapted to live in the harsh environment.

The researchers returned to the Atacama in 2016 and 2017 to follow up on their initial sampling and found that the same microbial communities in the soil were gradually reverting to a dormant state as the moisture went away.

"In the past researchers have found dying organisms near the surface and remnants of DNA but this is really the first time that anyone has been able to identify a persistent form of life living in the soil of the Atacama Desert," Schulze-Makuch said. "We believe these microbial communities can lay dormant for hundreds or even thousands of years in conditions very similar to what you would find on a planet like Mars and then come back to life when it rains."

Implications for life on Mars

While life in the driest regions of Earth is tough, the Martian surface is an even harsher environment.

It is akin to a drier and much colder version of the Atacama Desert. However it wasn't always this way.

Billions of years ago, Mars had small oceans and lakes where early lifeforms may have thrived. As the planet dried up and grew colder, these organisms could have evolved many of the adaptations lifeforms in the Atacama soil use to survive on Earth, Schulze-Makuch said.

"We know there is water frozen in the Martian soil and recent research strongly suggests nightly snowfalls and other increased moisture events near the surface," he said. "If life ever evolved on Mars, our research suggests it could have found a subsurface niche beneath today's severely hyper-arid surface."

Next Steps

On March 15, Schulze-Makuch is returning to the Atacama for two weeks to investigate how the Atacama's native inhabitants have adapted to survive. He said his research team also would like to look for lifeforms in the Don Juan Pond in Antarctica, a very shallow lake that is so salty it remains liquid even at temperatures as low as -58 degrees Fahrenheit.

"There are only a few places left on Earth to go looking for new lifeforms that survive in the kind of environments you would find on Mars," Schulze-Makuch said. "Our goal is to understand how they are able to do it so we will know what to look for on the Martian surface."

Author: Will Ferguson | Source: Washington State University [February 26, 2018]

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Theory suggests root efficiency, independence drove global spread of flora

A new theory of plant evolution suggests that the 400 million-year drive of flora across the globe may not have been propelled by the above-ground traits we can see easily, but by underground adaptations that allowed plants to become more efficient and independent.

Researchers from Princeton University and the Chinese Academy of Sciences have posed a theory of plant evolution based
on root adaptations that allowed plants to become more efficient and independent. The cross sections above show that the
roots of plants such as the subtropical oak species Lithocarpus chintungensis (largest cross section, center left) and the
tropical species Parashorea chinensis (lower-right of largest cross section) retained their ancestral thickness and reliance
on the symbiotic fungi (purple ring) that surround the root to help it obtain nutrients. As plant species spread from their
nutrient-rich tropical origins, however, the root tips of plants such as the desert shrub species Tamarix ramosissima
(left of largest cross section) evolved to be thinner so they could more efficiently explore soil for nutrients, and they
have less dependence on symbiotic fungi [Credit: Zeqing Ma, Chinese Academy of Sciences]

As plant species spread north and south from their nutrient-rich tropical beginnings, the fine tips of their roots became narrower and more widespread to help them explore increasingly poor soil for vital nutrients, according to a study in the journal Nature led by researchers from Princeton University and the Chinese Academy of Sciences (CAS) in Beijing. In addition, as plants spread into unpredictable environments such as arid deserts they grew less dependent on the symbiotic fungi -- or mycorrhiza -- that colonize roots and help host plants obtain the essential plant nutrients nitrogen and phosphorous.

The findings reconsider how plants adapted to new environments as they evolved, said corresponding author Lars Hedin, the George M. Moffett Professor of Biology and chair and professor of ecology and evolutionary biology and the Princeton Environmental Institute. Scientists have in the past focused on above-ground characteristics, primarily leaf traits and the efficiency with which plants absorb sunlight for photosynthesis, he said.

Instead, Hedin said, he and his colleagues have found for the first time that root diameter and reliance on fungi -- or the lack thereof -- are the traits that most consistently characterize the plant community across entire biomes, which are large distinct communities of animals and plants such as a desert, temperate forest or savanna.

"These are the secret strategies that plants have used over time to take over the world," Hedin said. "Our goal was to unlock the understanding of those strategies, and our findings offer a new global theory for plant evolution. Hidden underground there has been a tremendous game of survival-of-the-fittest and we are fortunate to have the first-ever view of the science of that game.

"This work has major implications for conservation and our stewardship of the plant world," Hedin continued. "It provides some of the hidden, below-ground rules by which plants survive and spread. It's a global view of plant evolution at a time when global rules are essential for building climate models and understanding the biosphere."

Mingzhen Lu, first Princeton author and a graduate student in Hedin's research group, said that if root traits do in fact determine a plant's ability to withstand a particular environment, these findings could be valuable in conserving endangered species or projecting how plants might adapt to climate change.

"Our findings simplify how we can practically characterize a plant's strategy for obtaining nutrients," Lu said. "Knowing their underlying nutrient strategy will help us know how to preserve them, or know the conditions under which they could or could not survive."

Kurt Pregitzer, the Thomas Reveley Professor and dean of the College of Natural Resources at the University of Idaho, said this work could be especially useful in combating invasive species, which, in a highly mobile world, increasingly threaten biodiversity. Pregitzer is familiar with the research but had no role in it.

"Invasive species cause widespread displacement of native plants and tremendous economic impacts across the globe," Pregitzer said. "This study may open entirely new lines of scientific investigation that help us better understand how invasive-plant root systems help these exotic species outcompete native plants."

The researchers spent two years examining a database of root traits consisting of 369 species from seven biomes (above):
desert, grassland, Mediterranean, boreal, temperate, subtropical and tropical. Woody biomes are identified as shades
of tan-to-yellow and non-woody biomes are in shades of green. The researchers found that plants in tropical (light orange)
and subtropical biomes (beige) exhibited the largest range of root-tip diameters, from less than 0.25 millimeters up to
1 millimeter. These plants rely on soil fungi to provide nutrients, a similar strategy to that of Earth's earliest land plants.
Plants in biomes characterized by poor soil, cold winters and/or infrequent precipitation have a narrow root-diameter
range ideal for that environment. The desert (light green) and grassland (green) species studied all had root
diameters of less than 0.25 millimeters [Credit: Lars Hedin and Mingzhen Lu, Department
of Ecology and Evolutionary Biology]

The Nature paper is unique for its scale and careful application of scientific methods, Pregitzer said. "This study is the first conducted across a wide range of terrestrial environments and it demonstrates that plant species have evolved root strategies that are conserved within corresponding families, genera and species," he said. "These root traits likely facilitate plant success in highly competitive natural ecosystems."

The researchers spent two years examining a uniquely large database of root traits consisting of 369 species from seven biomes: desert, grassland, Mediterranean, boreal, temperate, subtropical and tropical.

These data were compiled over the course of a decade in the lab of late co-corresponding author Dali Guo, a professor at CAS' Institute of Geographic Sciences and Natural Resources Research. First author Zeqing Ma is a research associate in Guo's lab and co-author Xiangliang Xu is a colleague of Guo's. The paper's co-authors also included root experts Richard Bardgett, professor of ecology at the University of Manchester in the UK; David Eissenstat, professor of woody plant physiology at Pennsylvania State University; and M. Luke McCormack, a research associate at the University of Minnesota.

The researchers found that plants in tropical and subtropical biomes exhibited the largest diameter range for the finest root tips that forage for nutrients, from less than 0.25 millimeters up to 1 millimeter. These thicker-rooted plants employ what the authors call a "conservative" strategy -- similar to that of Earth's earliest land plants -- that relies on the soil fungi prevalent in wet, warm tropical and subtropical soils to provide nutrients. The researchers refer to nutrient-rich soil in consistently sultry environs as "predictable."

Meanwhile, fine-root diameters in "unpredictable" biomes characterized by poor soil, cold winters and/or infrequent precipitation fall within a narrower range ideal for that environment. For instance, the desert and grassland species studied all had root diameters of less than 0.25 millimeters. Root tips in these biomes evolved to be thinner so they could more efficiently explore soil for every unit of carbon the plant expends, and they have less dependence on symbiotic fungi.

The extensive data the researchers used allowed them to explore the evolution of plant roots to an extent never before possible, Lu said. "Below-ground plant ecology has been understudied, limited by a paucity of data," he said. "Because of that, the governing rule of what's going on below ground has been very poorly known."

"Thus far," Hedin added, "everybody has quite naturally tried to understand how plants are organized by looking at above-ground traits. But our findings do not follow the above-ground theories -- that was a surprise."

The study reveals that root and leaf evolution have followed different paths, Pregitzer said. Plant ecologists have known that the form and function of leaves are essential to a plant species' success, but "we did not understand if this was true across the tremendous diversity of plant root systems," he said.

"Interestingly, little was known about how plant roots have evolved to facilitate success in their native habitats," Pregitzer said. "Now we know that leaves and roots have responded to different evolutionary selective pressures, and we can start building a better understanding of how root form and function drive plant success within the tremendous biological diversity we see on Earth."

The findings align with ideas explored at Princeton that suggest that plants -- rather than being passive features of their environment -- have actively adapted to and shaped their environments, Hedin said. He was senior author of a 2015 paper in Nature Plants that suggested that ecosystems take their various forms because plants behave in ways that not only benefit themselves but also determine the productivity and composition of their habitats.

"Over evolutionary time, it's as if plants have actively explored the best strategies to safeguard their own survival," Hedin said. He and Lu brought this perspective to the database put together by their colleagues at CAS.

"We understood from a plant perspective how to bring evolutionary questions to their unique global dataset," Hedin said. "It was this great collaboration where we combined new ideas with years of painstaking fieldwork to produce this great result. It couldn't have happened without both sides."

Source: Princeton University [February 21, 2018]

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First evidence of surprising ocean warming around Galápagos corals

The ocean around the Galápagos Islands has been warming since the 1970s, according to a new analysis of the natural temperature archives stored in coral reefs.

Diane Thompson (left), Roberto Pépolas (center) and Alexander Tudhope (right) use a hydraulic drill to take a core
from a Porites lobata coral head near Wolf Island in the Galápagos [Credit: Jenifer Suarez, Cole lab]

The finding surprised the University of Arizona-led research team, because the sparse instrumental records for sea surface temperature for that part of the eastern tropical Pacific Ocean did not show warming.

"People didn't know that the Galápagos or eastern Pacific was warming. People theorized or suggested it was cooling," said lead author Gloria Jimenez, a UA doctoral candidate in geosciences.

Scientists thought strong upwelling of colder deep waters spared the region from the warming seen in other parts of the Pacific, she said.

"My colleagues and I show that the ocean around the northern Galápagos Islands is warming and has been since the 1970s," Jimenez said. The research is part of her doctoral work.

Jimenez studied cores taken from coral heads in the uninhabited northern part of Galápagos National Park. The cores represented the years 1940 to 2010. Corals lay down seasonal growth layers that serve as a natural archive of ocean temperatures.

Her analysis revealed that from 1979 to 2010, regional ocean temperatures increased almost 0.4 degrees F (0.2 degrees C) per decade -- about 1.1 degrees F (0.6 degrees C) overall.

The very strong El Niño of 1982-83 temporarily warmed the surrounding ocean so much that most of the corals in the southern part of the Galápagos died, said co-author Julia Cole, who collected the coral cores while she was a faculty member at the UA.

She is concerned about ocean warming around the northern Galápagos and parts of the eastern tropical Pacific.

"Warming in this area is particularly disturbing, because it's the only place that reefs have persisted in the Galápagos. This suggests those reefs are more vulnerable than we thought," said Cole, who is now a professor of earth and environmental sciences at the University of Michigan.

Cores collected in 2010 from a Porites lobate coral near Wolf Island in Galapagos Islands. The core,
now broken into three pieces, is 3.5 inches (8.9 cm) in diameter [Credit: Julia Cole © 2010]

The research paper, "Northern Galápagos corals reveal twentieth century warming in the eastern tropical Pacific," by Jimenez, Cole and their co-authors, Diane M. Thompson of Boston University in Massachusetts and Alexander W. Tudhope of the University of Edinburgh in the UK, is published in Geophysical Research Letters.

The National Science Foundation, the UK Natural Environment Research Council and the Philanthropic Education Organization Fellowship funded the research.

For 30 years, Cole, a paleoclimatologist, has been studying climate change and the El Niño/ La Niña climate cycle.

In 1989 she went to the Galápagos hoping to use the natural climate archives stored in corals to develop a long-term record of El Niño, but found that none of the large, old corals others reported had survived the intense warming of the 1982-83 El Niño.

"We went from site to site -- and they were all gone," Cole said. "One of my co-workers said, 'There used to be corals here, and now all I see is sand.'"

Years later, she heard large corals were still alive near Wolf Island in the remote northern part of the Galápagos archipelago, so in 2010 she followed up on the tip with a team that included co-authors Tudhope and Thompson, then a UA graduate student.

The team members dove to the reef and took several cores from large, blobby dome-shaped Porites lobata corals using an underwater hydraulic drill powered by vegetable oil. The three-and-a-half-inch (8.9 cm) diameter cores ranged from two to three feet long and had annual bands 0.4 to 0.8 inches (1-2 cm) wide. Each core showed damage from when the coral stopped growing during the 1982-83 El Niño and then started growing again.

Jimenez used chemical analysis to tease temperature information out of two of those coral cores.

After removing two cores from this Porites lobata coral colony near Wolf Island in the Galápagos, the University of
Arizona-led team of researchers plugged the drill holes. The cement plugs help the coral grow over the holes
and keep out animals out of the holes [Credit: Diane Thompson © 2010]

Coral skeletons are made mostly of calcium carbonate. However, corals sometimes substitute the element strontium for the calcium. Corals substitute more strontium when the water is cold and less when the water is warm, so the strontium/calcium ratio of a bit of skeleton can reveal what the water temperature was when that piece of skeleton formed.

Jimenez used a little drill bit to take a tiny sample every millimeter for the length of each core. She took 10 to 20 samples from each annual band of each core and analyzed the samples for the strontium/calcium ratio using atomic emission spectrometry.

She then used that information to create a continuous record of the region's ocean temperature from 1940 to 2010.

Because the El Niño/ La Niña climate cycle generates large fluctuations in ocean temperatures around the Galápagos and in the eastern tropical Pacific, long-term changes can be hard to spot.

Jimenez wanted to determine whether the region's ocean temperature changed significantly from 1940 to 2010. Therefore she analyzed her Galápagos coral temperature chronologies alongside published coral temperature chronologies from islands farther north and west and instrumental sea surface temperature records from the southern Galápagos town of Puerto Ayora and the Peruvian coastal town of Puerto Chicama.

Jimenez said her research convinces her that the ocean around the Galápagos and much of the eastern tropical Pacific is warming. She's concerned about the effect of warming seas.

"The Galápagos National Park has been designated a World Heritage Site because it's a special and unique place," Jimenez said. "Losing the corals would be an enormous blow to the underwater biodiversity."

Jimenez's next project involves analyzing an eight-foot-long Galápagos coral core she collected in 2015 that goes back to about 1850.

Author: Mari N. Jensen | Source: University of Arizona [February 21, 2018]

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Extreme-altitude birds evolved same trait via different mutations

On the Himalayan-enveloped Tibetan Plateau and the Altiplano plateau of South America - the world's two highest tabletops - a select few bird species survive on 35 to 40 percent less oxygen than at sea level.

A rendering of avian hemoglobin, the blood protein that captures and delivers oxygen
throughout the body [Credit: PNAS]

All extreme-altitude birds have evolved especially efficient systems for delivering that precious oxygen to their tissues. But a new study led by the University of Nebraska-Lincoln and Chinese Academy of Sciences has found that these birds often evolved different blueprints for assembling the proteins - hemoglobins - that actually capture oxygen.

Published in the Proceedings of the National Academy of Sciences, the study found that many species from the two plateaus underwent different mutations to produce the same result: hemoglobins more adept at snaring oxygen from the lungs before sharing it with the other organs that depend on it.

Those mutational differences often emerged even among closely related species residing on the same plateau, the study reported.

"You could imagine, just because of the different ancestral starting points, that the Tibetan birds maybe all went one (mutational) route, and the Andean birds typically did things a different way," said co-author Jay Storz, Susan J. Rosowski Professor of biological sciences at Nebraska. "But that's not what we saw. Across the board, there weren't really any region-specific patterns.

"In both cases, it seems like there were many different ways of evolving a similar alteration of protein function."

Jay Storz stands on the Tibetan Plateau, more than 15,000 feet above sea level. Storz and his colleagues have shown that
many high-altitude bird species underwent different mutations to develop the same adaptation: hemoglobin better at
capturing and distributing scarce oxygen [Credit: University of Nebraska-Lincoln]

Like all proteins, hemoglobin consists of intricately folded chains of amino acids. The interactions among those amino acids dictate the structure of a protein, which in turn determines its properties - how readily it binds with and releases oxygen, for instance. But a mutation can effectively swap out an amino acid for a chemically distinct version at the same site in the protein, potentially modifying its behavior in the process.

After comparing the ancestral vs. modern hemoglobin proteins of nine species that inhabit the Tibetan Plateau, the team did identify two cases in which distantly related species underwent identical, functionally important mutations. Yet in the other instances, species evolved different ways to build a better hemoglobin.

The latest findings reinforce a 2016 Storz-led study published in the journal Science, which was the first to establish that vertebrate species can follow different molecular-level paths to reach the same adaptation. That study, which investigated birds only from the Andes, inspired the team to follow up with its comparison of Andean and Himalayan species.

"Birds that have adapted to high-altitude conditions from all these different mountain ranges have repeatedly evolved hemoglobin with elevated oxygen affinities," Storz said. "At that (functional) level, everything is highly repeatable, and there's a very striking pattern of convergent evolution. But in terms of the actual molecular underpinnings, there's far less predictability, and it's clear that there are many possible changes that can produce the same functional outcome."

Source: University of Nebraska-Lincoln [February 20, 2018]

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Land use change has warmed Earth's surface

Natural ecosystems play a crucial role in helping combat climate change, air pollution and soil erosion. A new study by a team of researchers from the Joint Research Centre, the European Commission's science and knowledge service, sheds light on another, less well-known aspect of how these ecosystems, and forests in particular, can protect our planet against global warming.

Changes to the way land is used is having a knock-on effect on temperatures
[Credit: European Commission Joint Research Centre]

The research team used satellite data to analyse changes in global vegetation cover from 2000 to 2015 and link these to changes in the surface energy balance. Modifying the vegetation cover alters the surface properties - such as the amount of heat dissipated by water evaporation and the level of radiation reflected back into space - which has a knock-on effect on local surface temperature. Their analysis reveals how recent land cover changes have ultimately made the planet warmer.

"We knew that forests have a role in regulating surface temperatures and that deforestation affects the climate, but this is the first global data-driven assessment that has enabled us to systematically map the biophysical mechanisms behind these processes", explains Gregory Duveiller, lead author of the study.

The study also looked beyond deforestation, analysing changes between different types of vegetation, from evergreen forests to savannas, shrublands, grasslands, croplands and wetlands. However, they found that the removal of tropical evergreen forest for agricultural expansion is the vegetation cover transition most responsible for local increases in surface temperature.

From a greenhouse gas perspective, the cutting of forests might only affect the global climate in the mid-to-long term. However, the scientists point out that local communities living in areas where the trees are cut will immediately be exposed to rising temperatures.

The findings are published in Nature Communications.

Source: European Commission Joint Research Centre [February 20, 2018]

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Biodiversity loss raises risk of 'extinction cascades'

New research shows that the loss of biodiversity can increase the risk of "extinction cascades," where an initial species loss leads to a domino effect of further extinctions.

Credit: Andreas Haselböck/Senckenberg

The researchers, from the University of Exeter, showed there is a higher risk of extinction cascades when other species are not present to fill the "gap" created by the loss of a species.

Even if the loss of one species does not directly cause knock-on extinctions, the study shows that this leads to simpler ecological communities that are at greater risk of "run-away extinction cascades" with the potential loss of many species.

With extinction rates at their highest levels ever and numerous species under threat due to human activity, the findings are a further warning about the consequences of eroding biodiversity.

"Interactions between species are important for ecosystem (a community of interacting species) stability," said Dr Dirk Sanders, of the Centre for Ecology and Conservation at the University of Exeter's Penryn Campus in Cornwall. "And because species are interconnected through multiple interactions, an impact on one species can affect others as well.

"It has been predicted that more complex food webs will be less vulnerable to extinction cascades because there is a greater chance that other species can step in and buffer against the effects of species loss.

"In our experiment, we used communities of plants and insects to test this prediction."

The researchers removed one species of wasp and found that it led to secondary extinctions of other, indirectly linked, species at the same level of the food web.

This effect was much stronger in simple communities than for the same species within a more complex food web.

Dr Sanders added: "Our results demonstrate that biodiversity loss can increase the vulnerability of ecosystems to secondary extinctions which, when they occur, can then lead to further simplification causing run-away extinction cascades."

The study, supported by France's Sorbonne Université, is published in the journal Proceedings of the National Academy of Sciences.

How extinction cascades work

The loss of a predator can initiate a cascade, such as in the case of wolves, where their extinction on one mountain can cause a large rise in the number of deer. This larger number of deer then eats more plant material than they would have before. This reduction in vegetation can cause extinctions in any species that also relies on the plants, but are potentially less competitive, such as rabbits or insects.

Source: University of Exeter [February 19, 2018]

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Action plan released to conserve one of Africa's richest sites for biodiversity

A team of scientists led by WCS (Wildlife Conservation Society) has developed a conservation blueprint to protect one of the most biodiverse regions in Africa: the Albertine Rift, home to mountain and Grauer's gorillas, golden monkeys, chimpanzees, elephants, and 162 vertebrate, and 350 plant species unique to this region.

Grauer's gorilla. A team of scientists led by WCS (Wildlife Conservation Society) has developed a conservation blueprint
 to protect one of the most biodiverse regions in Africa: the Albertine Rift, home to mountain and Grauer's gorillas,
golden monkeys, chimpanzees, elephants, and 162 vertebrate, and 350 plant species unique to this region
[Credit: A.J. Plumptre]

Based on work by WCS and participants from five countries in the region, the "Conservation Action Plan for the Albertine Rift" summarizes the results of 16 years of research and commitment to the conservation of six key landscapes within the Albertine Rift, which runs through five countries (Uganda, Democratic Republic of Congo, Rwanda, Burundi, and Tanzania) and stretches from the southern tip of Lake Tanganyika to the northern tip of Lake Albert

Building on an initial framework plan developed in 2004, the new plan highlights the importance of the region for global biodiversity and goes further to outline the main steps required for the conservation of each landscape. The plan assesses where within each landscape is most important for the conservation of the many unique and threatened species, both now and under projected climate change, and identifies which species remain unprotected.

"The Albertine Rift is the most important site for vertebrate conservation in Africa, with more endemic and globally threatened vertebrates than any other region of the continent," said Dr. Andy Plumptre, Senior Scientist for WCS's Africa program. "We know of 163 terrestrial vertebrates that are unique to this region and we keep discovering new species. We also know the lakes in this region have incredible fish diversity and that at least 350 species of plant are unique to the region."

WCS has conducted surveys of the biodiversity of the Albertine Rift over decades, supporting surveys of some species and specific sites as early as 1959 in the case of eastern gorillas (one of the endemic species). A more comprehensive program started by WCS in 2000 compiled region-wide data on mammals, birds, reptiles, amphibians and plants. WCS worked with other NGO partners and the environmental protection authorities of Burundi, the Democratic Republic of Congo, Rwanda, Tanzania, and Uganda to identify six key landscapes and to establish cooperative protection at ground-level in each.

Based on work by WCS and participants from five countries in the region, the 'Conservation Action Plan for
the Albertine Rift' summarizes the results of 16 years of research and commitment to the conservation of six key
 landscapes within the Albertine Rift, which runs through five countries (Uganda, Democratic Republic of Congo,
Rwanda, Burundi, and Tanzania) and stretches from the southern tip of Lake Tanganyika
to the northern tip of Lake Albert [Credit: WCS]

Threats to the landscapes are substantial because this part of Africa also contains some of the highest human population densities on the continent. Habitat loss is the most critical threat for most of the species. Modeling work described in the report showed that the endemic and threatened species have already lost on average 40 percent of suitable habitat to agriculture. Climate change is likely to drastically reduce the remaining suitable habitat.

"We predict that by the end of this century, endemic species will further decline in response to climate change as many of these species will need to move to higher elevations as the climate warms. These up-slope movements will result in a dramatic 75 percent reduction in suitable habitat," said Sam Ayebare, a conservationist for WCS Uganda.

Many of the areas currently under protection are essential for the conservation of these species. Three additional areas, totaling over 10,000 square kilometers, that were gazetted in 2016, Itombwe, Ngandja and Kabobo Reserves, were critical for protecting many additional endemic species, both now and under future climate change. The report assesses the optimum ways to conserve these endemic and globally threatened species, and identifies which areas not currently under protection remain important for the conservation of some of the species.

"These critical sites outside of the existing protected areas mostly occur in DR Congo," said Deo Kujirakwinja, Technical Advisor for WCS in DR Congo. "We need to focus our attention on these sites before they, and the unique species they contain, are lost."

Supporting the conservation and management of the six landscapes within the Albertine Rift will require a dedicated effort from governments and from the conservation community. However, investment in conservation in this region yields tremendous value because of its incredible species richness.

Available at: www.albertinerift.org

Source: Wildlife Conservation Society [February 15, 2018]

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Hunting is changing forests, but not as expected

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]

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Research identifies 'evolutionary rescue' areas for animals threatened by climate change

As winters arrive later and snow melts earlier, the worldwide decrease in snow cover already may have dramatic impacts on animals that change coat colors with the seasons. An international scientific team led by University of Montana Professor L. Scott Mills has set out to discover whether adaptive evolution can rescue these animals in the face of rapidly changing climate.

Brown and white snowshoe hares on snow at a University of Montana research facility
[Credit: L.S. Mills research photos by Jaco and Lindsey Barnard]

Twenty-one species of mammals and birds rely on the ability to change their coat color from brown in summer to white in winter to avoid fatal encounters with predators, but in some parts of their range individuals forgo the white molt and remain brown in winter.

"Weasels in the southern U.S. and mountain hares in Ireland, for example, have evolved to remain brown year-round," Mills said. "This is a genetic adaptation to retain camouflage in areas where snow is intermittent or sparse."

Mills' group previously found that winter white snowshoe hares confronting snowless ground have higher mortality rates that could drive massive population declines as snow duration continues to decrease. Other scientists have pointed to coat-color mismatch against snowless ground as a cause for recent range decreases of hares, ptarmigan and other species.

Brown and white snowshoe hares on bare ground at a University of Montana research facility
[Credit: L.S. Mills research photos by Jaco and Lindsey Barnard]

In a new article in Science, Mills' team identified areas that could foster rapid "evolutionary rescue" of these species particularly vulnerable to climate change. The study describes how the international team mapped "polymorphic zones" for eight color-changing species, including hares, weasels and the Arctic fox. In these zones, both brown and white individuals coexist in winter.

"These areas hold the special sauce for rapid evolutionary rescue," Mills said. "Because they contain winter-brown individuals better adapted to shorter winters, these polymorphic populations are primed to promote rapid evolution toward being winter brown instead of white as climate changes."

The authors emphasize that these hotspots for evolutionary rescue are not magic fortresses that will prevent climate change effects on wild animals.

"Ultimately, the world must reduce carbon dioxide emissions or else the climate effects will overwhelm the ability of many species to adapt," co-author Eugenia Bragina said. "But by mapping these adaptive hotspots, we identify places where people could help foster evolutionary rescue in the short term by working to maintain large and connected wildlife populations."

Source: The University of Montana [February 15, 2018]

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Rapid evolution of a calcareous microalgae

When simulating future environmental conditions researchers face a problem: laboratory experiments are easy to control and to reproduce, but are insufficient to mimic the complexity of natural ecosystems. In contrast, experiments under real conditions in nature are much more complicated and difficult to control. Scientist of the GEOMAR Helmholtz Centre for Ocean Research Kiel have combined both approaches to investigate the response of a major plankton species to increasing ocean acidification.

Emiliania huxleyi cells in an electron microscopic picture
[Credit: Lennart Bach, GEOMAR]

The concentration of carbon dioxide (CO2) in the atmosphere increases continuously. As a consequence, an increasing amount of CO2 dissolves in the ocean, where it reacts to carbonic acid and acidifies the seawater. As ocean acidification progresses steadily, scientists aim to assess the implications of this process for marine ecosystems.

A team of researchers from the GEOMAR Helmholtz Centre for Ocean Research Kiel has for the first time examined the adaptability of the calcified alga Emiliania huxleyi to ocean acidification in a combination of laboratory and field experiments. "Some of the algae lineages in the experiment showed an extremely rapid change in their ecological fitness. We did not expect that to happen," says lead author Dr. Lennart Bach from GEOMAR. The study has been published recently in the international journal Nature Ecology and Evolution.

The current experiments were preceded by years of laboratory tests with Emiliania huxleyi at the GEOMAR in Kiel. Dr. Kai Lohbeck, co-author of the new study, had been keeping the algae under increased CO2 concentrations. Three years later, it became apparent that Emiliania huxleyi coped better with acidification than at the beginning of the experiment. "For us, that was a clear indication for the adaptability of the algae. But the experiment took place under laboratory conditions. Therefore, the question remained whether the evolutionary adaptation during an isolated lab experiment would bring an advantage also under natural conditions," says Lohbeck.

The opportunity to investigate this question emerged in the spring of 2013. The research group of Professor Ulf Riebesell conducted experiments with the Kiel Offshore Mesocosms in the framework of the collaborative project BIOACID (Biological Effects of Ocean Acidification) on the influence of ocean acidification on natural communities in Gullmarsfjord in Sweden. From the laboratory in Kiel, some of the already adapted algae cultures as well as the associated control groups were taken along to Sweden. There, they were added to the plankton communities which were acclimated to high CO2 levels in the field experiments.

"To our surprise, we found that the algae lineages that had already been adapted to ocean acidification in the lab did not cope any better at lower pH levels than the control groups that had never experienced acidification before," says Dr. Bach. An equally surprising finding: Although all algal lineages had the same ancestors, they differed significantly in their ability to compete in the natural plankton community after only three years. While some lineages proliferated rapidly, others tended to be excluded from the natural community, regardless of whether or not they were previously adapted to ocean acidification. "This demonstrates Emiliania huxleyi's ability to evolve rapidly," Bach resumes the results of the study.

Prof. Riebesell, co-author of the study and coordinator of the BIOACID project, sees this as an indication of how little we understand the long-term effects of ocean acidification: "The organisms' ability to adapt to new environmental conditions surprises us again and again. However, it does not change the fact that as ocean acidification progresses, many species will be unable to maintain their ecological niches. The loss of biodiversity is therefore inevitable."

Source: Helmholtz Centre for Ocean Research Kiel (GEOMAR) [February 14, 2018]

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A theory of physics explains the fragmentation of tropical forests

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]

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First scientific expedition to newly exposed Antarctic ecosystem

A team of scientists, led by British Antarctic Survey (BAS), heads to Antarctica this week (14 February) to investigate a mysterious marine ecosystem that's been hidden beneath an Antarctic ice shelf for up to 120,000 years.

Larsen C ice shelf [Credit: NASA/Nathan Kurtz]

The iceberg known as A68, which is four times of London, calved off from the Larsen Ice Shelf in July 2017. The scientists will travel by ship to collect samples from the newly exposed seabed, which covers an area of around 5,818 km2. It is an urgent mission. The ecosystem that's likely been hidden beneath the ice for thousands of years may change as sunlight starts to alter the surface layers of the sea.

The international team, from nine research institutes, leaves Stanley in the Falkland Islands on 21 February to spend 3 weeks in February-March 2018 on board the BAS research ship RRS James Clark Ross. Satellite monitoring is critical for the ship to navigate through the ice-infested waters to reach this remote location.

Marine biologist Dr Katrin Linse from British Antarctic Survey is leading the mission. She says: "The calving of A68 provides us with a unique opportunity study marine life as it responds to a dramatic environmental change. It's important we get there quickly before the undersea environment changes as sunlight enters the water and new species begin to colonise. We've put together a team with a wide range of scientific skills so that we can collect as much information as possible in a short time. It's very exciting."

The team will investigate the area previously under the ice shelf by collecting seafloor animals, microbes, plankton, sediments and water samples using a range of equipment including video cameras and a special sledge pulled along the seafloor to collect tiny animals. They will also record any marine mammals and birds that might have moved into the area. Their findings will provide a picture of what life under the ice shelf was like so changes to the ecosystem can be tracked.

This newly exposed marine area is the first to benefit from an international agreement made in 2016 by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). This agreement designates Special Areas for Scientific Study in newly exposed marine areas following the collapse or retreat of ice shelves across the Antarctic Peninsula region. The agreement came following a European Union proposal to CCAMLR, led by British Antarctic Survey (BAS) scientists.

Professor David Vaughan, Science Director at BAS says: "The calving of A68 offers a new and unprecedented opportunity to establish an interdisciplinary scientific research programme in this climate sensitive region. Now is the time to address fundamental questions about the sustainability of polar continental shelves under climate change.

We need to be bold on this one. Larsen C is a long way south and there's lots of sea ice in the area, but this is important science, so we will try our best to get the team where they need to be."

Prof. Dr. Angelika Brandt from the Marine Zoology department is on board representing the Senckenberg Research Institute and Natural History Museum. During and after the Larsen-C expedition Brandt and collaborators will focus on biodiversity and assemblage structure assessment of the epi- and suprabenthic peracarid crustaceans and their respective colonisation in this newly developed benthic ecosystem.

While the team mobilises for the expedition, glaciologists and remote sensing specialists continue to monitor the movement of the Larsen C Ice Shelf. In December 2017, a team from University of Leeds worked on the remaining ice shelf to investigate changes in ice structure after the calving event, to be able to predict shelf stability in the future.

Source: Senckenberg Research Institute and Natural History Museum [February 13, 2018]

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'Middle Earth' preserved in giant bird dung

While the giant birds that once dominated New Zealand are all extinct, a study of their preserved dung (coprolites) has revealed many aspects of their ancient ecosystem, with important insights for ongoing conservation efforts.

Moa skull [Credit: FunkMonk/WikiCommons]

Published in the Proceedings of the National Academy of Sciences, the study, by the University of Adelaide's Australian Centre for Ancient DNA (ACAD) and Landcare Research NZ, reconstructed the prehuman New Zealand ecosystem using coprolites ranging from 120 to 1500 years old.

The ancient dried dung originated from four species of extinct giant moa and the critically endangered kakapo parrot, and contained genetic records of diet, pathogens, and the behavior of the birds. Such detailed pictures of the pre-historic ecosystem are critical for present-day ecological restoration efforts, but are not available from the conventional fossil record of preserved skeletons.

The ancient dung samples were excavated from caves and rockshelters across New Zealand by Dr Jamie Wood, of Landcare Research. He says, "Coprolites were actually more common than we'd thought, once we started looking for them. And it turns out they contain a huge range of important information about past ecosystems."

Lead author Alex Boast, a PhD student at Landcare Research says, "A key finding was that the giant birds were eating a wide range of mushrooms and fungi, including species that are critical for the beech forests that are widespread across New Zealand. The brightly colored mushrooms remain distinctive parts of these forests today, but it appears they were meant to be eaten and then distributed by the moa.

"Worryingly, introduced mammals which consume these mushrooms don't appear to produce fertile spores, so this critical ecosystem function of the giant birds has been lost -- with serious implications for the long-term health of New Zealand's beech forests."

The research was performed at ACAD where Postdoctoral Research Associate and microbiome specialist, Dr Laura Weyrich, says, "Moa coprolites contained a surprising diversity of parasites, many completely new to science. Several parasites appear to be specialized to single moa species, so that a range of parasites became extinct with each moa species. As a result, we have probably underestimated the loss of biodiversity associated with the extinction of the megafauna."

ACAD Director, Professor Alan Cooper, who led the study, says, "The wide diversity of DNA we retrieved from the dung has allowed us to reconstruct many aspects of the behavior and interactions of species that we've never been able to see before. This important new method allows us to see how prehuman ecosystems have been altered, which is often hard to identify, and to guide our efforts in correcting some of the resulting damage."

Source: University of Adelaide [February 12, 2018]

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