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Temporal lags in the response of populations to climatic variation associated with the NAO are widespread in both terrestrial and marine environments. The existence of both immediate and lagged responses to climate presents conceptual and analytical challenges to the study of the ecological consequences of large-scale climatic variability, as well as to the ability to forecast population responses to future climatic change. This chapter discusses the influence of atmospheric processes, life history, and trophic interactions on time lags. It argues that the existence of time lags in a multitude of systems can be exploited to one obvious advantage: prediction. Hence, an empirically-derived basis for improving conceptual and analytical understanding of lagged responses to climate should prove valuable in the pursuit of scientifically robust predictions of population and community response to future climate changes.

Biodiversity in freshwater food webs can be considered in terms of the number of species occupying unique trophic positions or the number of species within a trophic position. Either can affect energy flow or biomass partitioning, and the two aspects of diversity may feed back on one another. This chapter analyses the importance of biodiversity in aquatic food webs on three different levels. First, it asks how varying diversity within trophic groups affects the outcome of trophic interactions. It then presents a conceptual framework and contrasts this model against experimental manipulations of consumer or prey diversity. Second, it asks how consumers and resources affect biodiversity within trophic levels. This question has a long history of experimental and modeling studies, and these are reviewed. The role of biodiversity at local and regional spatial scales for freshwater food webs is examined. Dispersal among local habitats can constrain local species diversity and influence the outcome of food web interactions. The interactive effects of the regional pool versus resident diversity on the outcome of trophic interactions are discussed.

The composition of the present-day California marine fish fauna is largely a reflection of trophic interactions. This chapter first organizes the subject of food and feeding in fishes into three parts and variously draws examples from members of the California marine fish fauna. It discusses factors that determine diet including body shape and feeding behavior, identifies types of food capture, and describes several kinds of feeding mechanisms. Second, it describes some of the major types of food items consumed by representative taxa of the California fauna and associate these taxa with standard trophic level designations. Third, it uses generalized profiles of trophic relationships to portray the main feeding interactions among fishes occupying bay-estuarine, inner and outer shelf, rocky intertidal, rocky reef and kelp bed, epipelagic, and deep midwater habitats.

Trophic interactions, as many other relevant ecological processes, are spatially extended. Previous work has pointed out the importance of the spatial domain for understanding food webs. This chapter builds on this body of work by considering how space shapes food web structure. It considers two case studies. First, it studies whether the global structure of Doñana's food web (south-eastern Spain) is homogeneous on each habitat type, or whether different habitat types have subwebs with different structure. Second, it considers in several geographic locations in southern Spain the food web formed by the genera Turdus and the plants whose fruits they consume. It looks at how food web structure at each spatial location is related to structure at other locations.

This chapter discusses some of the characteristics of reef fish ecology that lead to such a wide range of forms and sizes seen in reef fish. Geographic drivers for fish diversity are examined at a range of scales, from global historical events to local-scale forces. Colour diversity in modern reef fish is examined, along with mechanisms that have developed to enhance feeding success or predation avoidance. Different ecological feeding niches of coral reef fish are described, using examples to illustrate the wide range of feeding mechanisms. Linking with feeding ecology, the food chain is examined, and the ‘inverted pyramid’ of the coral reef food chain discussed. Finally, the implications of changes in the reef community through fishing and future climate change on the food chain are examined, highlighting the cascade effect of impacts on reefs.

This chapter uses the tool developed in Part I of the book to disentangle the observed relationship between the architecture of the food webs and their stability. Here, the stability of the developed models is studied in order to see what properties may be important to stability. Using a collection of soil food webs, the chapter demonstrates that the observed pyramidal distributions of biomass, energy flux rates, and interaction strengths, and the organization of the food web into dominant pathways of interactions and fluxes, reflect the energetic organization of these communities. In fact, these patterns even enhance their stability. Furthermore, the chapter explores the interrelationships between energetic properties of food webs, particularly the maximum loop weight interaction loops within food webs and stability. Using empirically derived models, traditional stability analyses, and the analyses based on trophic interaction loops, it concludes with a foundation for the topics to come in the remaining chapters.

Birds function within their ecosystems in ways that include many direct and indirect chains of trophic interaction. In some interaction chains, birds exert top-down effects in “trophic cascades.” These occur when a predatory species directly reduces its prey abundance and consequently indirectly releases suppression of species at lower trophic levels. Many bird species initiate trophic cascades in terrestrial and aquatic ecosystems, and in natural and agro-ecosystems. Services provided by birds through trophic cascades benefit humans primarily through pest control in natural forests, forestry plantations, fruit orchards, and a variety of crop-based agro-ecosystems. Cascade strength may be affected by predator prey specificity, redundancy, species diversity, and productivity. Some birds influence ecosystem function both through either bottom up interactions or through intermediate trophic positions within interaction networks. These effects can also reverberate through trophic webs. Global change, including anthropogenic perturbation, may lead to a loss of ecosystem services, including seed dispersal and pollination services by birds. These losses may cause declines keystone or foundation plant species, resulting in losses in biodiversity and ecosystem integrity. We conclude with suggestions for future research needs on bird ecosystem services, particularly in light of global change.

This chapter takes a look back at the energy flux food web description that was developed in the previous chapter and attempts to derive a functional food web description from it. A functional food web description would be one that is able to portray the impact of each species on the population sizes and dynamics of other species in the food web. It includes several metrics that allow for the study of the importance of individual species and species in aggregate to the structure and stability of the food web. The first step, then, in this process is to develop a simple model of trophic interactions – or the who-eats-who structure of the community – that melds the differential equations developed in Chapter 2. From this, the chapter goes on to estimate interaction strengths among the functional groups and additional metrics.

This chapter examines the effects of management and intensification processes on biodiversity in agricultural landscapes. It begins with a meta-analysis of studies conducted along landscape gradients, then reviews relationships between biodiversity and ecosystem function within managed ecosystems. Pest control exemplifies the complexity of the functions of biodiversity in managed ecosystems (e.g., often correlating poorly with species richness, involving several trophic levels, and influenced by characteristics of the wider landscape). Finally, based on these analyses, this chapter describes an interdisciplinary context to link research on biodiversity and ecosystem function to end-users at different management scales that incorporates the influence of social and economic factors.

This chapter explores a special type of community organization: the compartmentalization and hierarchal arrangement of trophic interactions, energy flow, and biomass in space and time. Beginning with a brief background on the complexity and diversity debate, it then defines compartments in a food web context, using information from the developed connectedness, energy flux, and functional descriptions arrived at in previous chapters. This is for the purpose of presenting different approaches that have been employed in the past when studying compartments. This methodology also serves as a means to review the evidence for and against the presence of compartments of species within food webs, and to discuss the theoretical reasons behind the formation and persistence of compartments.

This chapter discusses grazing, which is the major agent of loss of kelp second to water motion and natural senescence of fronds. A rich and diverse array of species makes their living feeding on kelp and kelp-derived detritus within most kelp forests, both directly and indirectly through the food web and trophic interactions. These interactions occur across many feeding types and up to five trophic levels, including primary producers, primary consumers, secondary consumers, and tertiary consumers. Primary consumers include grazers that feed directly on living attached algae, detritivores feeding on detached drift or litter material, and planktivores feeding on material produced in or imported into a kelp forest. Animals that feed on algae range in size from microscopic crustaceans and snails to large herbivorous fishes. By far, the most important grazers in almost all kelp forests worldwide are sea urchins, removing attached plants, and creating unforested patches largely devoid of all kelps and other macroalgae.

This chapter examines how species in simple community modules evolve in order to adapt to one another. It first considers the ecological basis of natural selection before discussing the three general types of traits that underlie the trophic interactions between predators and their prey. It then explores how the type of traits involved in species interactions affect the dynamics of adaptation and describes the underlying dynamics of adaptation when all the species in a simple community module can coevolve, along with the influences of various system features on the outcome of this coevolution. The chapter focuses on the simultaneous dynamics of abundances and traits that result from species interactions by looking at the case involving one resource and one consumer, with only trait being ecologically important for each species, and how this simple consumer-resource system evolves when a third trophic level is added to the system.

This chapter discusses how food webs are connected, through the use of a connectedness food web description. This is a simple box-and-arrow diagram that depicts the trophic interactions – or the interactions between living creatures where one is either eating or being eaten – among species within an ecosystem. Essentially, the descriptions provide a snapshot of the natural history of a portion of the ecosystem, as well as the patterns of material flows within it. The chapter thus presents an approach to constructing a connectedness description. This approach is one which optimizes the information about species, capturing the natural history in such a way that it allows for an easier and more seamless connection between trophic interactions, energy flow, and stability. As a model to walk through this approach, the well-studied soil food web of the Central Plains Experimental Range (CPER) model will be the chapter’s basis for design.

The productivity of California grasslands is limited by nitrogen, phosphorus, potassium, sulfur, or water at various sites, and studies finding limitation by multiple resources are common. This chapter reviews this evidence, and explores resource limitation patterns and how they affect plant community productivity, functional group composition, and trophic interactions.

Although we must understand the mechanical nuts and bolts of inheritance, evolution occurs through changes in the population frequencies of traits, trait values, and genes in time and space, values that depend at least as much on the dynamics of populations as on the mechanics of inheritance. This chapter demonstrates the crucial roles of ecology in evolutionary change. There are two major types of dynamics that are essential to model evolution. The chapter develops the principles of strategy dynamics to examine the processes responsible for the success and failure of some traits, and trait values, over others. Different traits and their values represent competing strategies to be tested by adaptive evolution. The success of each strategy depends on the spatial and temporal dynamics of populations, and their respective influences on those dynamics. The chapter merges strategy and population dynamics to evaluate the evolutionary stability of competing strategies.

This chapter explores the role of animal migrations for the communities and ecosystems that surround them. Animal movement can impact ecosystems through the transfer of materials, by shifting the intensity of trophic interactions across space and through time, and by propagating disease and genetic material. Migration can be differentiated from other modes of animal movement in terms of spatial extent and temporal predictability, and these differences have consequences for interactions (such as competition and predation) with non-migrating species. The chapter focuses specifically on ungulate migrations, given their highly vulnerable status, and examines through a series of theoretical exercises their potential impacts on aspects of ecosystem function and community composition.

This chapter discusses the alternative ways to interpret elemental trophic interactions mathematically. It outlines the prey-dependent models, predator-dependent models, and ratio-dependent models used in the entire text. It focuses first on the Monod and Contois equation of growth and compares both approaches in describing the growth rate of bacteria as a function of sugar concentration. It then considers the Arditi-Ginzburg ratio dependent functional response which argues that the predation, reproduction, and mortality are truly continuous processes and are operating on the same timescale in a perfectly mixed environment. The chapter also proposes the gradual interference model, and highlights that the conversion of prey biomass is one requirement that predator-prey models must obey.

This chapter discusses factors that have led to reef fish diversity. Geographic drivers for fish diversity, ranging from global historical events to local-scale drivers, are examined. Age and growth in reef fish are explored, followed by larval fish ecology. Colour diversity in modern reef fish is examined, along with mechanisms that have developed to enhance feeding success or predation avoidance. Different ecological feeding niches of coral reef fish are described and examples are given to illustrate the wide range of feeding mechanisms. The science around the abundance, biomass and trophic interactions of reef fish assemblages is examined. The range of fish feeding habits is detailed and functional roles of fish explored. Finally, the implications of changes in the reef fish community through fishing and habitat degradation are examined, highlighting the cascade effect of impacts on reefs, and how the influences of different disturbances interact to influence coral reef fish.

Although the changes in the chemistry of seawater driven by the uptake of CO2 by the oceans have been known for decades, research addressing the effects of elevated CO2 on marine organisms and ecosystems has only started recently (see Chapter 1). The first results of deliberate experiments on organisms were published in the mid 1980s (Agegian 1985) and those on communities in 2000 (Langdon et al. 2000; Leclercq et al. 2000 ). In contrast, studies focusing on the response of terrestrial plant communities began much earlier, with the first results of free-air CO2 enrichment experiments (FACE) being published in the late 1960s (see Allen 1992 ). Not surprisingly, knowledge about the effects of elevated CO2 on the marine realm lags behind that concerning the terrestrial realm. Yet ocean acidification might have significant biological, ecological, biogeochemical, and societal implications and decision-makers need to know the extent and severity of these implications in order to decide whether they should be considered, or not, when designing future policies. The goals of this chapter are to summarize key information provided in the preceding chapters by highlighting what is known and what is unknown, identify and discuss the ecosystems that are most at risk, as well as discuss prospects and recommendation for future research. The chemical, biological, ecological, biogeochemical, and societal implications of ocean acidification have been comprehensively reviewed in the previous chapters with one minor exception. Early work has shown that ocean acidification significantly affects the propagation of sound in seawater and suggested possible consequences for marine organisms sensitive to sound (Hester et al . 2008). However, sub sequent studies have shown that the changes in the upper-ocean sound absorption coefficient at future pH levels will have no or a small impact on ocean acoustic noise (Joseph and Chiu 2010; Udovydchenkov et al . 2010). The goal of this section is to condense the current knowledge about the consequences of ocean acidification in 15 key statements. Each statement is given levels of evidence and, when possible, a level of confidence as recommended by the Intergovernmental Panel on Climate Change (IPCC) for use in its 5th Assessment Report (Mastrandrea et al. 2010).