3649-08 IICB.indd - Faculty of Biological Sciences - University of ...

Stephen Cornell
MA, DPhil (Oxford);
Postdoctoral research fellow, Universities of Cambridge, Manchester, Guelph, Geneva (1990-2001);
Wellcome Trust Junior Research Fellow, University of Cambridge (2001-2004);
University Research Fellow (2004-)
Contact: s.j.cornell@leeds.ac.uk
Dynamics of
interacting populations
I’m interested in the way that biological
populations fluctuate over time and
space. The study of population
dynamics is fundamental to (i) ecology,
which is primarily concerned with the
patterns of abundance of species;
(ii) epidemiology, where the impact
of a pathogen is determined by its
ability to colonise and spread through
host populations; and (iii) evolution,
where a successful phenotype is one
which is able to increase in number
relative to its peers. The underlying
demographic mechanisms of birth,
death, and immigration, together with
genetic processes such as mutation
and recombination, can be formulated
mathematically, but these processes
interact in a highly complex manner
to produce emergent biological
phenomena.
The goal of my research is to
understand the role played by
interactions – between individuals of
the same or different species, and over
space – in determining the dynamics of
populations. One very theoretical aspect
to my research is the development
of new methods for analysing the
`interacting particle systems’ that
underpin demographic processes
– recent work on metapopulations
represents the first mathematically
exact analysis of nonlinear spatial
population dynamics. We are currently
extending these methods to other
ecological scenarios such as a spatial
Lotka-Volterra system and a neutral
model of tree community dynamics.
Work on nematode parasites has
pointed to the importance of spatial and
stochastic processes in determining
the frequency of epidemics and the
emergence of drug resistance.
More empirically-driven research
projects include the community
dynamics of parasites of rabbits, where
the seasonal patterns of the hosts’
immune response play a crucial role,
and the within-phagocyte dynamics
of salmonella in mice, where a simple
model of bacterial proliferation and cell
lysis explains the observed distribution
between cells. I also have some more
applied research interests: recent
work has suggested a framework for
reconciling the competing demands
of agricultural production and
conservation, and I am modelling
the response of biodiversity to land
use as part of a consortium studying
sustainable management of uplands in
the UK.
Funding for these projects has come
from a variety of sources, including
the Wellcome Trust, Royal Society,
Leverhulme Trust, and the Rural
Economy and Land Use Programme
(NERC/BBSRC/ESRC).
More information:
http://www.fbs.leeds.ac.uk/staff/profile.
php?staff=bgysc
Representative Publications
Ovaskainen, O, and Cornell, SJ. (2006)
Asymptotically exact analysis of stochastic
metapopulation dynamics with explicit spatial
structure, to appear in Theoretical Population
Biology (published online at http://www.
sciencedirect.com/science/article/B6WXD-
4HD8B4S-1/2/ 38e98f0a3b83e6e66e998bb
6251440e8)
Green, RE, Cornell, SJ, Schnarlmann, JPW and
Balmford, AP. (2005) Farming and the fate of
wild nature. Science 307: 1257-1258
Cornell, SJ, Isham, VS and Grenfell, BT.
(2003) Spatial parasite transmission, drug
resistance, and the spread of rare genes.
Proceedings of the National Academy of
Sciences USA 100: 7401-7405
Ovaskainen, O and Cornell, SJ. (2003) Biased
movement at a boundary and conditional
occupancy times for diffusion processes.
Journal of Applied Probability 40: 557-580