Species Competition and Predation - Ecological Systems - page 248

be completely separated [ 118 ]. The field of adaptive dynamics tries to integrate
ecological and evolutionary process, but nevertheless still tends to treat these two
processes as functioning on different timescales [ 119 ]. At the same time, much
study of species coexistence focuses on the conditions that allow species coexis-
tence, without considering the processes by which species assemble in
communities. A proper treatment of community assembly would include challeng-
ing a local community with invaders from the pool species present regionally.
There have been only limited theoretical studies of this sort [ 83 , 120 , 121 ]. Without
an adequate treatment of these processes of adaptation and assembly, there is no
true prediction of the structure of natural communities, and a seriously incomplete
understanding of the role of competition and predation in community structure.
Finally, future theoretical research will likely take on the challenge of long-term
climate change. The planet faces relative rapid climate change at the hand of human
activities, but long-term climate change has always been a feature of the environ-
ment. However, theoretical models normally assume that climate fluctuations have
stable long-term frequencies. There is a critical need to strip away this assumption,
and develop theory that allows predictions even though the climate is not statisti-
cally stable. A useful theory would couple long-term climate change with the ability
of populations to move on a spatially structured landscape as climate shifts change
the viability of parts of their habitat. With such migration, there is the potential that
climate fluctuations realized by species will have stable long-term frequencies as
species track the shifting climate, but there are bound to be numerous new issues
arising due to the fact that different species are likely to track the environment at
different rates and in different ways [ 122 ].
A few years ago, imagining developments in the directions discussed here would
have been daunting given the challenges that simpler theory gave. However, recent
progress augers major extensions beyond the current limited contexts.
Acknowledgments I am grateful for comments on the manuscript by Jonathan Levine and for
support from the National Science Foundation grant numbers DEB-0717222 and DEB-0816231.
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