Food-web theory in marine ecosystems

Abstract

Abstract This chapter examines recent case studies of marine food webs to evaluate the applicability of food web theories for the marine environment. Classical macrodescriptors and recent network metrics are evaluated for each marine food web example. Food webs are defined as those which are non-estuarine, non-coastal, and larger in scale than food webs typically and classically studied (i.e., not a bay, not a river-ocean mixing zone, not a rocky inter-tidal zone, etc.). There are clear distinctions for marine food webs when compared to all terrestrial and other aquatic food webs, yet there are also clear distinctions among different types of marine food webs. The chapter notes that there are three categories of food web theories: (i) those factors and models which apply categorically to all food webs; (ii) those factors and models which can be split into simple, lowly connected, strongly interacting, clearly defined localized food webs versus complex, highly connected, weakly interacting, broader, more extensive food webs; and (iii) those factors and models which are uniquely and distinctly marine. Understanding the qualitative properties of food webs can provide further evaluation of which theories are appropriate, which are not, when each is true, and why. Finally, the chapter discusses the applications and implications of these theories for ecosystem-based natural resource management.