Thursday, 30 August 2012

The death of the conker tree?

We need your help to discover whether blue tits may be the salvation of the UK’s conker trees, which are currently under attack from a leaf-mining moth.
The moth arrived in London just ten years ago, and has since spread across most of England and Wales. The moth caterpillars eat the leaves of the conker tree while hiding inside them, so damaging the leaves and causing them to turn brown and making the tree appear as if autumn has come early.
Since 2010 the Conker Tree Science project, led by Dr Michael Pocock at the Centre for Ecology & Hydrology (CEH) and Dr Darren Evans at the University of Hull, has been trying to find out the extent of the damage from the moth and also examine possible solutions to the problem.  The scientific team has involved members of the public in a series of  "missions". Mission 1 asked members of the public to contribute data on the spread of the moth across the UK; Mission 2 examined how many alien moths are being killed by pest controllers; Mission 3, launched today, asks members of the public to count the number of bird attacks on horse-chestnut leaves.

Each bird attack creates distinctive holes in the top surface of the leaf, where the caterpillar of the leaf-mining moth was living. Each attack means one less moth, and so could result in less damage to the horse-chestnut trees.

To take part in this real scientific research visit the Conker Tree Science website.

More details of the new mission ‘Bird Attack’ can be found here.
The Horse Chestnut Leaf-miner moth Cameraria ohridella Credit Dave Kilbey
A blue tit in front of horse-chestnut leaves that are covered with brown patches of damage caused by the caterpillars of the leaf mining moths. Credit: Richard Broughton/CEH

The signs of a bird attack on the leaf mine home of the alien moth that is damaging our horse-chestnut trees. Credit: Dr Michael Pocock/CEH

Thursday, 23 August 2012

From drought to flood – An Olympian Summer for hydrological change

Just four months ago more than ‘half of Britain was in drought’ with the UK facing its most severe water shortage since 1976. The Environment Minister was urging households to cut back on the amount of water they used, some rivers in England were at their lowest April levels for 36 years, and your correspondent was quoted in the Guardian stating “This [the late April rain] is not the solution for the deep aquifers which have been at some of the lowest levels ever recorded. We are still looking at next winter rainfall to recharge these.”

As many of you will have noticed the driest March in the UK for 59 years was followed by the wettest April in 101 years. The accumulated rainfall since then has been remarkable. In the four months from the beginning of April to the end of July rainfall amounts were the highest on record (from 1910) by a considerable margin in almost all regions of Great Britain, and provisionally the highest in the England & Wales rainfall series from 1766. Groundwater resources have recovered to levels that expert hydrologists and geologists had thought wouldn’t occur until the end of a (hopefully wet) winter 2012-2013. All hosepipe bans in southern England have been lifted and although groundwater levels remain low in slowly-responding parts of the Chalk and the Permo-Triassic sandstone, our most recent monthly Hydrological Summary for the UK was able to confidently state “The transformation in water resource status since early April is without any close modern parallel.”

Back in early May I was also asked by John Vidal of the Guardian to comment on what may happen if the ‘monsoon’ like conditions in April continued. My words, reproduced in the next day’s paper, were, "If it carries on like this for another few months things may improve [from a hydrological point of view]. But by then we will all be totally fed up." My prophecy was partially correct, the rain did carry on, and things did improve, but as far as I can tell, we’re not all totally fed up, perhaps thanks to an amazingly successful Olympics! Oh well, I suppose two out of three isn’t bad!

Barnaby Smith

April to July 2012 UK River flows

Tuesday, 21 August 2012

The Plynlimon catchments - an open air laboratory

The Plynlimon catchments in central Wales are the most important intensively studied long-term research basins in the UK. Managed by the Centre for Ecology & Hydrology (CEH), Plynlimon is among the key European and world sites in terms of catchment science - not just for the length of the records gathered (40 years and counting) but crucially because of the breadth of measurements, spanning hydrology and including water chemistry, groundwater studies, geomorphology, ecology and atmospheric science.

With the study now in its fifth decade, and inspired by a new paper* by Dr Mark Robinson, working with former colleagues John Rodda and John Sutcliffe, who played key roles in establishing Plynlimon, we take a look at the history behind the establishment of one of CEH's most significant scientific experiments, a long-term environmental monitoring project which has evolved and adapted to stay relevant to current problems and scientific needs.

Landscape view over the Plynlimon catchments in central Wales (photo: Simon Grant / CEH)

In the mid-20th century, against a backdrop of population growth, rising living standards and post-war industrial recovery, there was growing concern in the UK about increased demand for water and possible future water shortages. A severe drought in summer 1959 and dry winters in 1962/3 and 1963/4 underlined the belief in government circles that a national plan for water use was needed, as it seemed likely that demand would soon outstrip available resources.

There were concerns too about other factors potentially affecting water availability, not least the government's policy of encouraging widescale tree planting on reservoir catchments. The rapid growth characteristics of the conifer and the cheapness of the land resulted in conifer plantations on many upland regions of Britain throughout the first half of the 20th century. However, there were conflicting scientific views on the hydrological impact of forests, with some catchment studies, particularly in the USA, indicating that tree cover could reduce water yield relative to short vegetation.

Research in the late 1950s by Frank Law Senior, a water engineer in north-west England, tried to find out more about the water balance of woodlands under British conditions. His conclusions were controversial: that afforestation of the Stocks reservoir catchment area was substantially reducing runoff, with the additional evaporation representing a reduction in reservoir yield of over one third. At a time of anticipated increasing domestic and industrial water demands, the debate about water versus forestry was set for the decades ahead.

British hydrology and water industry were still rather fragmented in the decade after the Second World War, but these national pressures meant that more rational management of water resources was required. The particular need to understand the role of vegetation in the hydrological cycle led to the creation by the Department of Scientific and Industrial Research (DSIR) of a Committee on Hydrological Research in 1961. This committee soon proposed the establishment of a specialist unit to be responsible for applied research into surface water hydrology, including studies of the water balance of catchment areas in relation to land use.

The new Hydrological Research Unit was set up in the following year and attached to the existing Hydraulics Research Station at Wallingford in Oxfordshire. A steering group was appointed to guide its studies, with a range of potentially competing stakeholder representatives from the Forestry Commission, Nature Conservancy, Water Research Association, Met Office and Agricultural Research Council.

The Unit was asked to conduct a hydrological study of catchments with contrasting land cover, preferably grassland and coniferous forest, since that was seen as the land use distinction most likely to reveal differences in behaviour and was the most common source of land use concern.  The catchments would need to be on watertight geology, and it was felt that the difference in water used by the two vegetation types would be most clearly apparent in relatively dry climate.

Where exactly to base the experiment was not a straightforward decision. It proved difficult to identify pairs of almost identical catchments that differed only in their vegetation and had landowner agreement for access. Plynlimon was not even on the original eight potentially suitable paired catchments identified. The climate criterion was later relaxed to include ‘wet’ sites, and the adjoining headwater catchments of the Severn and the Wye rivers draining the slopes of Pumlumon Fawr, i.e. Plynlimon, were added to the list, and later judged to be the most promising of the possible sites. The headwaters of each catchment provide a land use contrast between the two major upland land uses: moorland (Wye) and plantation forest (Severn).

In addition to the ongoing scientific debate concerning forest evaporation, the organisational framework for UK environmental research was undergoing major change as part of a wider government reorganisation. In 1965 the HRU was transferred to the newly formed Natural Environment Research Council (NERC). The Unit’s remit was then expanded to encompass all aspects of the hydrological cycle including physical and applied studies, instrumentation and mathematical modelling.

The Plynlimon study officially started on 1 January 1967, with the NERC Annual Report foreseeing it as being an “outdoor laboratory of immense value to all sciences”. The delays in establishing a field site actually afforded the opportunity to develop expertise in cutting edge instruments and new technologies. There was pioneering work (widely adopted elsewhere) on neutron probes for soil water content measurement, as well as automatic weather stations capable of operating at remote locations, and new raingauge designs for windy sites.

Cefn Brywn crump weir on the River Wye, late 1960s

In recognition of the growing importance of hydrological research in Britain, NERC designated the HRU as a full component institute: on 1 April 1968 it became the Institute of Hydrology, which later became part of the Centre for Ecology & Hydrology. The Plynlimon study played a crucial role in proving beyond doubt the potentially serious reduction in water flows resulting from afforestation, leading to major changes in the management of water and land use by resource managers and policy makers.

Work continues at the Plynlimon catchments to this day. CEH conducts long-term measurements of weather, streamflow and chemical fluxes. We use this information to look for time trends, understand the processes operating, and investigate the impacts of land use on water resources, floods, drought flows, stream sediment and dissolved chemicals and acidification. 

Other Plynlimon research highlights

·        The original aim of the Plynlimon catchment experiment was to make measurements which could resolve the uncertainties concerning the water use of conifer forests. It not only helped to answer this question but subsequently developed into a long-term multi-disciplinary project.

·        Building upon the established catchment infrastructure, hydrochemical measurements commenced and now more than almost 30 years are available, together with the longer record of hydrological data.

·        The Plynlimon catchments have been one of the more successful catchment studies, advancing science and its findings have directly altered UK forestry environmental policy and informed UK government policy.

·        The Plynlimon study provided a considerable stimulus to the development of the science of hydrology in Britain. The research findings have been reported in more than 500 papers in refereed journals, and much of the Plynlimon record has been freely available to the international research community for decades, and is also accessible via the internet from the CEH Information Gateway.

Summarising the importance of the Plynlimon catchments, Dr Mark Robinson told us, “We owe a great debt to the farsightedness of the stakeholders and academics who recognised the need for, and supported the establishment of, the research catchments at Plynlimon. The catchments provided an important focus in British hydrology, promoting excellence in experimental hydrology and advancing our understanding of the physical processes controlling the hydrological cycle.”

Additional information

* The full paper reference is: Robinson, M., Rodda, J.C., and Sutcliffe, J.V. (2012), Long-term environmental monitoring in the UK: origins and achievements of the Plynlimon catchment study. Transactions of the Institute of British Geographers. doi: 10.1111/j.1475-5661.2012.00534.x 

View archive photos from Plynlimon on Flickr

CEH: Why monitor upland catchments? [PDF, 4.95mb]

Monday, 6 August 2012

How safe are nanoparticles? The NanoFATE project is finding out…

The NanoFATE project is the subject of a major feature in the latest issue of International Innovation magazine, published today (6 August 2012).

Nanotechnology is employed in a diverse range of industries and sectors to create or enhance materials and products at the fantastically small nano level (one-billionth of a metre). Nanoparticles have been used in familiar consumer products like suntan lotions, eyeglasses and food packaging as well as in sectors such as computer technology, biology and medicine. But alongside the rapid advances in such technology is the need to reassess the environmental risk assessments that help ensure nanotechnology is managed and implemented safely.

NanoFATE is a major EU-funded collaborative project that investigates the fate and effects of engineered nanoparticles (ENPs) in the environment, from their initial entry into the environment (for example, whether through vehicle exhaust fumes into the air, or suntan lotion or anti microbial additives washed down the plughole), through to their different forms and effects, to whether there is a potentially toxic impact on water, soil etc.

NanoFATE involves advanced imaging. Here the spatial distribution of metals in organs of a woodlouse
exposed to silver ENPs is captured at the Diamond Light Source (UK) Synchotron by NanoFATE's
Cardiff, Aveiro, Oxford and NERC teams.

Now halfway through its four-year programme, the project is the subject of a major feature in the latest issue of International Innovation magazine, which is published today.

The NanoFATE project coordinator is Dr Claus Svendsen, an ecotoxicologist with the NERC Centre for Ecology & Hydrology (CEH), who talks to the magazine about the potential environmental issues presented by engineered nanoparticles, some of the practicalities involved with such a collaboration (NanoFATE is a multidisciplinary project involving 12 partner organisations from 9 European countries), applications resulting so far from the project and its scientific highlights.

Claus and other project leaders from the University of Oxford and Vrije University, Amsterdam, also talk about NanoFATE's major components, as well as its aims of providing tools and knowledge that can be applied in practice.

Claus tells the magazine, "We constantly improve assessment realism as we build better understanding of ENPs' environmental behaviour, organisms' uptake and resulting toxicity. The final aim is to make dynamic risk maps for Europe by meshing our developing knowledge on ENP safety with accurate exposure prediction models."

Additional information