The role and importance of optimal foraging theory in ecology

Abstract

and diversity and the factors that structure populations and communities. On the other hand, behavioural ecologists have concerned themselves mainly with functional explanations of the behaviour of individual animals, the role that ecology plays in determining behaviour and the fitness consequences of behavioural decisions made by animals. Many have argued in the past that an understanding of the factors controlling dynamic processes at the population and community levels cannot be complete without some knowledge of the behaviour of the individuals that comprise the population. Perhaps fewer have championed an opposite, top-down approach to investigating ecological phenomena, with studies of population and community processes preceeding and forming the framework within which functional questions about animal behaviour can be more effectively addressed. Of course, both approaches have their merits as well as limitations. This round-table discussion was focused mainly at the interface between behavioural ecology and population and community ecology and on assessing whether foraging theory can lead to an increased understanding of the complex, dynamic processes that occur at the population and community levels. There was general agreement among the discussion leaders and participants that an understanding of the latter phenomena cannot be complete without knowledge of how individual animals respond behaviourally to a wide range of ecological factors, such as gradients of food resources, competitors and predation pressure for example, which may in turn have implications for population and community structures. That is, a bottum-up approach to such inquiry would appear to be most appropriate and fruitful. In this context, foraging theory provides a functional framework to investigate the foraging behaviour of individuals and the dynamics of predator-prey interactions. In contrast, population and community ecologists have typically viewed the population as a unitary black box, with little or no attention given to the components of the population, namely the individuals. Foraging theory, optimization models and the experimental approach have proved useful in certain cases (particularly in aquatic systems) in predicting the utilization of space and food by individuals across food, competitor and predator gradients. Understanding the behavioural responses of individuals to such ecological factors may explain observed patterns of spatial distribution, food resource utilization and mortality due to predation of animals within a population at