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Ecological communities consist of species that interact to varying degrees within the same geographical area, and so by definition exist within a landscape context. This chapter begins by reviewing the measures and different scales at which species diversity can be assayed, including the use of spatial partitioning to evaluate multiscale patterns of diversity. The chapter then reviews correlates of species diversity, including explanations for latitudinal and elevational diversity gradients, before considering how habitat loss and fragmentation are expected to influence species diversity. The chapter tackles the debate surrounding the relative importance of habitat amount versus fragmentation in predicting species’ responses to landscape change, and highlights the importance of studying these effects at a landscape rather than patch scale. The chapter concludes with a discussion of landscape effects on different types of species interactions, and how interactions among species in different communities can give rise to metacommunity structure and dynamics.

This chapter considers how exotic birds interact with native species, and how they serve to re-shape global biodiversity patterns. Both exotic and native species are distributed unevenly across the environment, such that some areas house more species, and other areas house fewer. The origins of these distributions for exotic and native bird species are undoubtedly very different, yet they share several common features, such as species-area relationships on islands, and latitudinal gradients. The chapter examines whether the same processes produce the same patterns in each set of species, and what this says about the causes of distribution patterns in native species, and also in exotics. It then considers the associations that exotic species forge in their recipient communities through their biotic interactions with native species, including native birds.

This chapter examines the distribution of bats and their relationship with the environment. It looks into the various species area relations (SARs) that vary with organism, ecosystem, geographical region, and the scale of investigation. It studies mechanisms likely to interpret species-area relationships. It discusses the contributions of molecular genetics in determining the patterns of bat colonization and speciation by studying data gathered from various sampling sites. It investigates the interface between species-area relationships and community ecology by applying this to bats by analyzing them as predators, as prey, and their relationship with plants.

This chapter examines how biodiversity, the variety of life, is distributed across the globe and within local communities. It begins by considering some of the challenges associated with assessing biological diversity at different spatial scales. Then, three of the best-studied patterns in species richness are examined in detail—the species–area relationship, the distribution of species abundances, and the relationship between productivity and species richness. The chapter concludes with a detailed exploration of the most dramatic of Earth’s biodiversity patterns—the latitudinal diversity gradient. The above patterns constitute much of what community ecology seeks to explain about nature. Their study provides a foundation from which to explore mechanisms of species interactions, and to understand the processes that drive variation in species numbers and their distribution.

This chapter presents METE, a comprehensive, parsimonious, and testable theory of the distribution, abundance, and energetics of species across spatial scales. It develops the structure and predictions of the theory. These predictions include species abundance distributions, species–area relationships, distributions of metabolic rates across individuals, abundance–metabolic rate relationships, and spatial distribution patterns for individuals within species. Predictions all stem from prior knowledge of four ecological state variables – area, species richness, total abundance, and total metabolic rate – which are to ecology what pressure, volume, and temperature are to thermodynamics.

Estuaries are among the most productive areas on earth, and fish biomass in these habitats ranks with that of the marine regions of upwelling, coral reefs, and kelp beds. This chapter characterizes California bay-estuarine fish assemblages from two broad perspectives: latitudinal distribution patterns, and major ecological features. The coastline from Humboldt Bay in northern California to Laguna de Ojo Liebre in central Baja California spans about 11° of latitude and crosses biogeographic boundaries and environmental gradients, especially of temperature and rainfall. This perspective can be divided into two components: species-area relationships, and classification based on salt tolerance and life-history pattern, which relate generally to the ecological classification of the entire California marine fish fauna. The overarching ecological features of diversity, productivity, seasonality, inter-annual variability, and nursery function are important in portraying and understanding bay-estuarine fish ecology.

The Indo-West Pacific region (IWP) has more species of mangrove than the Atlantic-Caribbean-East Pacific (ACEP). This and other biogeographical patterns can be understood only with reference to tectonic movements, the evolutionary diversification of mangroves, and barriers to dispersal. Local species diversity and intraspecific genetic diversity are affected by distance from source populations, and by species/area relationships. Similar considerations apply to the biogeography and biodiversity of seagrasses. Although difficult to establish unequivocally, high diversity seems to render an ecosystem more productive, less prone to fluctuation, and more resilient.

A major goal of ecology is to predict patterns and changes in the abundance, distribution, and energetics of individuals and species in ecosystems. The maximum entropy theory of ecology (METE) predicts the functional forms and parameter values describing the central metrics of macroecology, including the distribution of abundances over all the species, metabolic rates over all individuals, spatial aggregation of individuals within species, and the dependence of species diversity on areas of habitat. In METE, the maximum entropy inference procedure is implemented using the constraints imposed by a few macroscopic state variables, including the number of species, total abundance, and total metabolic rate in an ecological community. Although the theory adequately predicts pervasive empirical patterns in relatively static ecosystems, there is mounting evidence that in ecosystems in which the state variables are changing rapidly, many of the predictions of METE systematically fail. Here we discuss the underlying logic and predictions of the static theory and then describe progress toward achieving a dynamic theory (DynaMETE) of macroecology capable of describing ecosystems undergoing rapid change as a result of disturbance. An emphasis throughout is on the tension between, and reconciliation of, two legitimate perspectives on ecology: that of the natural historian who studies the uniqueness of every ecosystem and the theorist seeking unification and generality.

Mechanisms of abiotic environmental factors influencing basic community properties like standing biomass, productivity, species diversity, structure, fluctuations, persistence, and resilience are discussed on the global, regional, and local spatial scales, encompassing timescales from the ecological to the evolutionary. The geographic distribution of species diversity and of plant strategies is related to environmental conditions, mainly to light and water availability. Effects of diversity on ecosystem functioning are addressed through comparative and experimental studies. The effects of species pool size and composition—which have evolved on an evolutionary timescale—are also considered in relation to their influence on the composition and the dynamics of communities at the ecological timescale. Finally, possible causes of the changes in community composition (β‎-diversity) are discussed, exemplifying the role of self-organizing patterns and alternative stable states.