Publication Abstract

Size based analysis of aquatic food webs

Size based analysis of aquatic food webs

S. Jennings

Size-based analyses of aquatic food webs, where body size rather than species identity is the principle descriptor of an individual’s role in the food web, provide insights into food web structure and function that complement those from species based analyses. A strength of the focus on body size is that body size underpins predator-prey interactions and dictates how the biological properties of individuals change with size. Thus size based food web analysis provides an approach for integrating community and ecosystem ecology with energetic and metabolic theory. Size based analyses of aquatic food webs principally focus on the shapes of the abundance- body mass relationship, or size spectra, and the processes that determine their remarkably uniform structure. Within size spectra, the energy available to individuals is constrained by the number of prey to predator energy transfers that support them. Thus the abundance of animals at a given body size, and hence the slope of the size-spectrum, is expected to depend on the mean predator prey body size ratio and trophic transfer efficiency. Recent practical and theoretical advances also suggest links between predator-prey body size ratios and food chain length, implying that environmental effects on predator-prey mass ratios may contribute to differences in the structure of aquatic communities. Analyses of size spectra also have applied significance since they provide a tool for predicting food web structure in the absence of human impacts.

Reference:

S. Jennings (2005) Size-based analysis of aquatic food webs. In: Aquatic food webs: an ecosystem approach (eds A. Belgrano, U.M. Scharler, J. Dunne & R.E. Ulanowicz), pp. 86-97. Oxford University Press, Oxford. 

S. Jennings*

Size-based analysis of aquatic food webs. In Aquatic food webs: an ecosystem approach (eds A. Belgrano, U.M. Scharler, J. Dunne & R.E. Ulanowicz), pp. 86-97. Oxford University Press, Oxford.