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IMPERIAL COLLEGE OF SCIENCE, TECHNOLOGY AND MEDICINE
TH Huxley School of Environment, Earth Science and Engineering
UNIVERSITY OF BRADFORD
Department of Environmental Science
VACANCY FOR A RESEARCH ASSISTANT:
Modelling the impacts of nitrogen deposition on Calluna-dominated ecosystems
Background
Increasing emissions of ammonia and nitrogen oxides have become a cause for
concern in recent decades, particularly in the context of their impacts on
sensitive natural and semi-natural systems that are adapted to low levels
of nitrogen availability. In the Netherlands, high rates of nitrogen
deposition are believed to be responsible for the loss of large areas of
heathland. This is thought to be largely a result of an enhanced
sensitivity of Calluna to biotic and abiotic stresses, providing
opportunities for competing grass species to become the dominant species;
however, other factors, such as changes in traditional management
techniques, may also be important. Experimental work carried out by
Imperial College since 1989 at Thursley Common, a lowland heath, has
demonstrated that even relatively small increases in nitrogen deposition
can affect a range of biological and chemical processes. However, no
evidence was found for either canopy breakdown or invasion by grasses after
seven years' experimental nitrogen additions. Since this may reflect the
relatively short experimental period in relation to the growth cycle of
Calluna, and the relatively low rates of nitrogen addition used, rather
than a lower sensitivity of British heathlands compared to those in the
Netherlands, a modelling approach has also been adopted to predict longer
term responses to a range of values of enhanced nitrogen deposition.
The model
A dynamic ecosystem model (CALLUNA), developed by colleagues in the
Netherlands, is being adapted to predict the fate of British heathlands
under different deposition scenarios. The model predicts the effects of
varying nitrogen deposition on the outcome of competition between Calluna
and the grass species Deschampsia flexuosa, incorporating periodic
ecosystem management and stochastic outbreaks of heather beetles, the
principal herbivore of Calluna. Where available, data collected from the
experimental site at Thursley Common has been used to parameterise the
model, with important changes to the management module making it more
appropriate to lowland systems in the U.K.
The position
We wish to appoint a research assistant, for a period of two years, to
further develop, parameterise, and test the model, and to apply it to wider
range of Calluna-dominated communities in the UK. The work will form part
of a wider programme of research on the ecological impacts of nitrogen
deposition in the UK, in which both institutions are involved and which is
supported by DETR. The research will involve data collection through a
combination of fieldwork and chemical analyses, literature searches and
discussions with individuals involved in heathland research and management.
Model development will initially concentrate on lowland heaths and will
involve the introduction of additional modules such as climate and other
stresses, and a wider range of management options. This will be followed by
research to modify the model for use with upland Calluna-dominated
communities. In the first year, the post will involve collaboration with
colleagues at the University of Utrecht, with occasional travel to the
Netherlands. In the second year, the post will involve collaboration with
colleagues in the north of England, and Scotland, as part of the wider UK
research programme.
The post is available for an initial period of two years, from 1 January
1999. It will be based at Imperial College's Silwood Park campus in Ascot,
Berkshire for the first year, and primarily at Bradford University in the
second year. The salary will be in the range £15462 to £17266, depending on
qualifications and experience. We welcome applications from candidates with
any relevant background, but practical experience of modelling work,
preferably in an ecological context, is essential. Applicants should send
copies of their c.v., by e-mail, to both Dr Sally Power
([log in to unmask]), at Imperial College, and Prof. Mike Ashmore
([log in to unmask]), at Bradford University. The deadline for
applications is 16 November, and interviews will be held in London or Ascot
on either Thursday 19th November or Friday 20th November 1998. If you wish
to discuss the post further, please phone either Dr. Power (01344-294318)
or Prof. Ashmore (01274-235695).
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Dr Sally Power
Lecturer in Air Pollution Impacts,
T.H. Huxley School,
Imperial College, Silwood Park,
Ascot, Berkshire SL5 7PY U.K.
Tel: +01344 294318
Fax: +01344 294339
Email: [log in to unmask]
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