1  What is theoretical ecology

Theoretical ecology has a relatively long history, with many initial developments occurring during the early part of the 20th century, perhaps culminating in the book by Gause (1934). There has also been much recent development spurred by and leading to advances in computation and statistics. A short list of some of the roles of theory (and perhaps we should distinguish mathematical theory) is:

See Kareiva (1989).

It is useful to compare theoretical ecology to other areas of science where theory has played a role, such as physics or population genetics. In particular, the comparison to physics can be interesting since in physics the distinction between model and reality is less clear cut.

2  Success stories in ecology

Throughout the course, we will focus on some of the simplest cases. Especially in understanding the role and impact of theory, and in understanding how to 'do' theoretical ecology, a return to basics is coessential.

There are at least two very different ways to begin thinking about the development of theory in ecology. One is the idea that essentially ecology can be reduced to understanding the distribution in space and time of the offspring of a new individual at a given location and time. This way may be very complex, but forces the examination of many of the important questions, in particular the idea that knowing what to leave out in a description is vital. The other approach would be to start from some rather phenomenological descriptions that can provide insights. We begin with several examples of this kind.

logistic equation

Although not useful as a predictive model, this is extraordinarily useful as a paradigm (e.g., Gause, 1934; Hutchinson, 1978). Thus, although we should not make much of the exact numbers the general conclusions can be very important. We will return to the concept of more predictive models later.

Competitive Exclusion

As stated by Gause (1934) the principle of competitive exclusion is in some sense a tautology, but much ecological research through the 1960's focussed on trying to work out the implications of this statement.


As already suggested included all the relevant detail of populations in time and space is impossible, so ecologists have looked for general ways to simplify their descriptions. The typical ways are to keep the descriptions of some processes while dropping others. Metapopulations provide one such example.

3  The question of relevant detail

More generally, one of the prime issues in the development of theory is understanding what details to include. This question is very easy to understand in the context of understanding forest dynamics.

See Levin (1992).


* means required reading

Cuddington, K. and Besiner, B. (eds.) 2005. Ecological Paradigms Lost. Academic Press.

Gause, G.F. 1934. The Struggle for Existence. Williams and Wilkins, Baltimore.

Green, J.L., Hastings, A., Arzberger, P., Ayala, F., Cottingham, K.L., Cuddington, K., Davis, F., Dunne, J.A., Fortin, M-J., Gerber, L., Neubert, M. (2005) Complexity in ecology and conservation: mathematical, statistical, and computational challenges. BioScience 55:501-510.

Hastings, A., Arzberger, P.,Bolker, B.,Collins, S., Ives, A.R., Johnson, N.A., Palmer, M.A. (2005) Quantitative Bioscience for the 21st Century. BioScience 55:511-517.

Hanski, I., Gilpin, M.E., eds. 1997. Metapopulation Biology: Ecology, Genetics, and Evolution. Academic Press, San Diego

Hutchinson, G.E. 1978. An Introduction of Population Ecology. Yale Unviersity Press, New Haven

*Kareiva, P. 1989. Renewing the dialogue between theory and experiments in population ecology. in Roughgarden et al., 1989.

Levin, S.A. 1992. The problem of pattern and scale in ecology,

Roughgarden, J. May, R.M., Levin, S.A., eds. 1989. Perspectives in Ecological Theory. Princeton University Press, Princeton

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