Search site

School of Geography

Research news

Most carbon dense ecosystem in Amazonia mapped for first time

Amazonian forests are known to harbour large stores of carbon locked up in their trees. However, results from a new study show surprisingly that the parts of Amazonia with the highest concentration of carbon store most not as wood, but below the ground, as peat.

The study was undertaken by researchers from the Universities of Leeds, St Andrews, Edinburgh (UK), and Turku (Finland), in collaboration with the Research Institute of the Peruvian Amazon (IIAP) and is published today in the journal Environmental Research Letters. The authors mapped and quantified the carbon stored in the largest area of peatland forest in Amazonia within a geological basin almost the size of England (120,000 km2). The researchers estimated that over three billion tons of carbon are stored within this ecosystem, with 90 % stored below the ground as peat.

“Peatland forests are different from other Amazonian forests as they are typically dominated by small-statured trees or palms. We can see these differences not only on the ground but also from space using satellite imagery. These differences allowed us to map the extent of the peatlands and distinguish the different types of peatland forest. Crucially this approach allowed us to distinguish a type of forest dominated by small trees, or ‘pole’ forest – the most carbon-dense peatland type” explains lead author Freddie Draper, a PhD student at the University of Leeds. “Combining this satellite data with extensive field data we have been able to provide spatially explicit estimates of the amount of carbon stored in these ecosystems for the first time”.

Ordinarily in tropical forests, the vast majority of carbon is emitted back to the atmosphere as carbon dioxide, as trees die and decompose. However, waterlogging in peatlands means that decomposition is very slow so the carbon accumulates as peat.

Dr Tim Baker, co-author and Associate Professor at the School of Geography, University of Leeds presented the results to policymakers at ’Voices for Climate’ on the margins of the recent UN Climate Change Conference COP20 in Lima, Peru. “Mapping and quantifying the amount of carbon stored in these ecosystems is an important part of prioritising national strategies to mitigate climate change. For example, these peatlands occupy just 3 % of the forested area of Peru, but contain almost 50 % of the total amount of carbon stored above the ground in all Peruvian forests”.

“The peatlands we studied are largely intact, in contrast to tropical peatlands in Southeast Asia that have been exposed to decades of destruction, leading to huge carbon emissions and biodiversity losses” added co-author Dr Katherine Roucoux, lecturer at the University of St Andrews. “However, most of the peatland area, including the most carbon-dense peatland type, currently lies outside of the protected areas and threats are increasing. If these carbon-rich forests could be protected too, then large emissions of carbon to the atmosphere could be prevented.”

Funding for the project came primarily from the UK Natural Environment Research Council (NERC).

http://www.bbc.com/news/science-environment-30448519

Climate change was not to blame for the collapse of the Bronze Age

Scientists have proven definitively that climate change could not have been responsible for a huge population collapse in Europe at the end of the Bronze Age.

Archaeologists and environmental scientists from the University of Leeds, the University of Bradford, University College Cork and Queen’s University Belfast have shown that the changes in climate that scientists believed to coincide with the fall in population in fact occurred at least two generations later.

Their results, published today in the Proceedings of the National Academy of Sciences, show that human activity starts to decline after 900 BC, and falls rapidly after 800 BC, indicating a population collapse. But the climate records show that colder, wetter conditions didn’t occur until around two generations later.

Dr Graeme Swindles, from the School of Geography, University of Leeds and a co-author of the study, said: “We found clear evidence for a rapid change in climate to much wetter conditions, which we were able to precisely pinpoint to 750 BC using statistical methods.”

Fluctuations in human activity levels through time are reflected by the numbers of radiocarbon dates for a given period. The team used new statistical techniques to analyse more than 2000 radiocarbon dates, taken from hundreds of archaeological sites in Ireland, to pinpoint the precise dates that Europe’s Bronze Age population collapse occurred.

Find out more

Study supervised by Jon Lovett shows the severe environmental impacts of armed conflicts on the Lebanon

Armed conflicts are responsible for severe environmental impacts due to both the direct effects of destruction and indirect effects resulting from the break down of law and social order. Northern Lebanon has experienced repeated conflicts over the last three decades, and in a recently published study resulting from a collaboration between Jon Lovett from the School of Geography, Leeds and the Universities of Balamand and Twente analyses change over time to demonstrate land degradation resulting from conflict. Mapping and monitoring land degradation are essential for designing and implementing post-conflict recovery plans and informed policy decisions.

The aim of the work was to evaluate the effect of repetitive armed conflicts on land degradation along the coastal zone of North Lebanon using multi-temporal satellite data. The specific objectives were to:

  • identify a list of indicators for use in conjunction with satellite remote sensi
  • monitor land cover change throughout repetitive events of armed conflicts and
  • model the effect of repetitive armed conflicts on land degradation.

The work involved the use of multi-temporal Landsat images and literature review data in Geographic Object-Based Image Analysis (GEOBIA) approach, together with 26 field visits to confirm interpretation of the images. The work resulted in the development of

  • a list of indicators to be employed,
  • land cover change detection maps with the use of multi-temporal Landsat images and, consequently, a fire risk associated with changes in vegetation cover throughout repetitive armed conflict events, and
  • an integrated approach for modelling the effect of repetitive armed conflicts on land degradation with the use of a composite land degradation index (CLDI).

The final synthetic map showed four classes of exposure to land degradation associated with repetitive armed conflicts. Data collected from field visits showed that the final classification results highly reflected (average of 90 %) the effect of repetitive armed conflicts on the different classes of exposure to land degradation.

Link to paper

find out more

Grouse moor burning causes widespread environmental changes

Evidence of the environmental effects of moorland burning is published today in the first authoritative scientific study on the subject, with the aim of relieving tensions on both sides of the grouse moor management debate.

The EMBER (Effects of Moorland Burning on the Ecohydrology of River basins) project has shown that heather burning on moorland, which is practised predominantly to support red grouse populations for gun sports, has significant negative impacts on peat hydrology, peat chemistry and physical properties, river water chemistry and river ecology.

A report on the five-year EMBER project is published online today – the first day of the moorland burning season, which will run until 15 April 2015.

Dr Lee Brown, from the School of Geography at the University of Leeds, who led the study, said: "Until now, there was little evidence of the environmental impacts of moorland burning. Yet, many moorland owners and individuals who hold sporting rights to the land have felt pressured by regulators and conservationists to change their burning regimes.

“Unsurprisingly, a push away from moorland burning – a practice that started in the UK about 100-150 years ago – without solid scientific evidence to back up the need for change has created a lot of tension. The findings from the EMBER project now provide the necessary evidence to inform policy.”

Find out more

Global importance of pollinators underestimated

Declines in populations of pollinators such as bees and wasps may be a key threat to nutrition in some of the most poorly fed parts of the globe, according to new research by Dr Guy Ziv.

A major study, published today in the Proceedings of the Royal Society B and co-authored by a University of Leeds academic, looked at the importance of pollinators to 115 of the most common food crops worldwide and the importance of those crops in delivering vital nutrients to vulnerable populations.

The research, the first to study the relationship between nutrition and pollination across the globe, found some regions where disruptions in pollination could have serious implications for human health.

Deficiencies in ‘micronutrients’—nutrients such as iron and vitamins that are required by the body in small quantities—are three times as prevalent where production of micronutrients is heavily dependent upon pollinators, such as Sub-Saharan Africa, India, and the Middle East.

In Southeast Asia and parts of Latin America, almost 50% of plant-derived vitamin A production relies on pollination.

Find out more

Super high-resolution survey in Greenland

Duncan Quincey, Jonathan Carrivick and Joe Mallalieu have been using an exciting new surveying technique to improve understanding of glacial flooding in Greenland.

Dr Duncan Quincey, Dr Jonathan Carrivick and Joseph Mallalieu (all School of Geography) used the emerging technique of ‘structure-from-motion with multi-view stereo’ (SfM-MVS) to analyse bedrock parts of a river channel at an unprecedented resolution.

“Worldwide, glacier margins are retreating, loss from glaciers is increasing and the consequent meltwater often forms temporarily ‘ponded’ in glacier lakes. Many of these lakes are unstable and can drain rapidly producing outburst floods,” explains Dr Carrivick. 

“Glacier outburst floods can cause loss of life, displacement of populations and damage to infrastructure, but our understanding of them is limited, due to their suddenness and short-lived nature and also the power of the flow which makes direct measurements extremely difficult. Flows are not easy to understand because they cause rapid landscape change, causing erosion and routing through complex channels. They frequently accelerate and decelerate, with rapid and abrupt changes in energy and capability to erode, transport and deposit sediment. So, new methods of surveying are needed to identify sources of sediment from outburst floods and the changes that take place between events.”

SfM uses novel digital photogrammetric and computer vision methods for simultaneously reconstructing camera pose and 3D feature geometry using multiple, overlapping digital photographs. It produces super high-resolution topographic models to improve flood modelling and also provides baseline data to compare future surveys against, allowing quantification of bedrock erosion and sediment redistribution.

 “This project collected the imagery using a combined ground-based and airborne approach,” explains Dr Carrivick. “Surveyors walked on the river banks, getting hand-held camera images at each new perspective, producing around 300 images for each site. Additionally, a quadcopter took multiple aerial photographs of the bedrock gorges, and was invaluable for speed of survey and for imaging inaccessible and exceptionally complex areas. The resulting topographic datasets have centimetre-decimetre resolution, which far surpasses any previous elevation models of the site.”

The team is now analysing the multi-scale data with a view to improving models of flood routing and propagation – for hazard analysis via information on time to inundation and hydraulics – and improving understanding of rapid bedrock erosion.The research was funded by the Royal Institute of Chartered Surveyors, administered by the Royal Geographical Society.

Archived news

  • View archived news here.