Wildlife Facing Extinction as Destruction of Soils Releases CO2
November 13, 2016
Duke University and Exeter University / Science Daily
Scientists warn that there are hundreds more species that are at risk of extinction than is currently recognized. Another study finds that, if people continue changing the land over the next century in the same way they currently do, soils will lose the ability to counter the effect of climate change and will become a net source of atmospheric carbon dioxide.
Remote Sensing Data Reveals
Hundreds More Species at Risk of Extinction
(November 10, 2016) -- A new Duke University-led study finds that more than 200 bird species in six rapidly developing regions are at risk of extinction despite not being included on the International Union for Conservation of Nature (IUCN) Red List.
The study, published Nov. 9 in the peer-reviewed journal Science Advances, used remote sensing data to map recent land-use changes that are reducing suitable habitat for more than 600 bird species in the Atlantic forest of Brazil, Central America, the western Andes of Colombia, Sumatra, Madagascar and Southeast Asia.
Of the 600 species, only 108 are currently classified by the IUCN Red List as being at risk of extinction.
The new analysis, however, reveals that 210 of the species face accelerated risks of extinction and 189 of them should now be classified as threatened, based on the extent and pace of habitat loss documented by recent remote sensing.
"Good as it is, the Red List assessment process dates back 25 years and does not make use of advances in geospatial technologies," said Stuart L. Pimm, Doris Duke Professor of Conservation Ecology at Duke's Nicholas School of the Environment. "We have powerful new tools at our fingertips, including vastly improved digital maps, regular global assessments of land use changes from satellite images, and maps showing which areas of the planet are protected by national parks."
By not incorporating this type of modern geospatial data directly into its assessments, Pimm said, the Red List is underestimating the number of species at risk and causing scientists and policymakers to overlook priority areas for conservation.
"The Red List employs rigorously objective criteria, is transparent, and democratic in soliciting comments on species decisions," he stressed. "That said, its methods are seriously outdated."
For instance, while the Red List currently includes estimates of the size of a species' geographical range in its assessment process, it fails to account for how much preferred habitat remains within that range, said Natalia Ocampo-Penuela, the new study's lead author, who received her Ph.D. from Duke earlier this year.
"Some bird species prefer forests at mid-elevations, while others inhabit moist lowland forests," she said. "Knowing how much of this preferred habitat remains -- and how much of it has been destroyed or degraded -- is vital for accurately assessing extinction risks, especially for species that have small geographical ranges to begin with. But it's ignored in the current Red List assessment process."
"When these factors are accounted for, some species that are not currently considered at risk of extinction likely have ranges that are smaller than those that the Red List otherwise quite sensibly decides are at risk," said study co-author Clinton Jenkins, who directs the biodiversity mapping site http://www.biodiversitymapping.org.
Added Ocampo-Penuela, "Natural habitats in the most biodiverse places on Earth are disappearing, pushing species toward extinction a thousand times faster than their natural rates.
Preventing these extinctions requires knowing what species are at risk and where they live," she said. "With better data we can make better decisions, and have a greater chance of saving species and protecting the places that matter."
N. Ocampo-Penuela, C. N. Jenkins, V. Vijay, B. V. Li, S. L. Pimm. Incorporating explicit geospatial data shows more species at risk of extinction than the current Red List. Science Advances, 2016; 2 (11): e1601367 DOI: 10.1126/sciadv.1601367
Soil Could Become a Significant
Source of Carbon Dioxide
University of Exeter / Science Daily
(November 3, 2016) -- If people continue using and changing the land over the next century in the same way they currently do, soils will have limited potential to counter the effect of climate change and will become a net source of atmospheric carbon dioxide, experts have warned.
Experts have forecast that a quarter of the carbon found in soil in France could be lost to the atmosphere during the next 100 years. This could lead to soil becoming a net source of carbon dioxide to the atmosphere. At present soil is considered to absorb carbon dioxide and this partially counters the impact of human-made climate change.
The pace and nature of predicted changes in climate over the next century will make the soil less able to store carbon, while business-as-usual land use change has limited capacity to counteract this trend, experts from the University of Exeter, INRA and CERFACS in France and University of Leuven in Belgium say in the journal Scientific Reports.
If, as predicted, soils lose a significant amount of their carbon this will endanger their ability to produce food and store water and this could lead to increased soil erosion and flood damage.
Researchers made these predictions for the 21st century by combining models of soil carbon and land use change with climate change predictions, using France as a case study. The study shows that land under almost all uses will be subject to dramatic losses of soil carbon by 2100.
Only conversions of land into grass or forest result in limited additional storage of carbon in soils. Unfortunately these land changes are not likely to happen on a large scale because of the pressures on land resources imposed by urban expansion and food production.
Lead author, Dr. Jeroen Meersmans, from the University of Exeter, said: "A reduction in anthropogenic CO2 levels is crucial to prevent further loss of carbon from our soils. However, promotion of land use changes and management that contribute to soil carbon sequestration remains essential in an integrated strategy to protect soil functions and mitigate climate change."
Co-author Dr. Dominique Arrouays of the French National Institute for Agricultural Research added, "Purposive, targeted land use and agricultural practice changes would be needed if climate change mitigation is to be maximized. Therefore, the efforts to enhance carbon sequestration in soils, as proposed by France during the COP21, should be promoted immediately."
The research collaboration involved academics from the Geography Department at the College of Life and Environmental Sciences at the University of Exeter (UK), the InfoSol Unit at INRA in Orleans (France), CECI, CERFACS -- CNRS in Toulouse (France), the Geography and Tourism Research Group at the Department of Earth and Environmental Sciences at the University of Leuven (Belgium).
Jeroen Meersmans, Dominique Arrouays, Anton J. J. Van Rompaey, Christian Pagé, Sarah De Baets, Timothy A. Quine. Future C loss in mid-latitude mineral soils: climate change exceeds land use mitigation potential in France. Scientific Reports, 2016; 6: 35798 DOI: 10.1038/srep35798
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