Populations of wild animals face the challenge of surviving in a
changing climate. Researchers at Imperial College London and Université
Claude Bernard Lyon have shown how a sheep population on a remote
island off the west coast of Scotland responds to two consequences of
climate change: altered food availability and the unpredictability of
Dr. Thomas Ezard, lead author of the study, revealed, "When times
are good and food is plentiful, lambs contribute almost twice as much
to changes in population size than when times are hard. On the flip
side, the oldest sheep contribute most to population growth when
conditions are harsh."
The work suggests that the dynamics of populations are influenced
not only by the weather but also by the ability of individuals to
respond to it.
New mathematical breakthroughs have made it possible to show how environmental change affects populations, like these sheep.
The key is appreciating
- how weather affects individual sheep and
- how the weather changes from one year to the next.
If consecutive years have similar weather, the dynamics of the
population will be very different than if conditions are unrelated from
one year to the next.
Professor Tim Coulson concluded, "A thorough understanding of the
likely effects of climate change on the ecology of wild populations
requires linking populations to their environment. This demands
application of innovative mathematical methods, as used here."
University of Chicago Press Journals. September 2008.