bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards a food web perspective on biodiversity and ecosystem functioning
Authors: Cardinale Bradley , Duffy Emmett , Srivastava Diane , Loreau Michel , Thomas Matt , Emmerson Mark 
Published: September 2009

AbstractWhile one of the most striking features of our planet is its great variety of life, studies show that ongoing biodiversity loss could reduce the productivity of ecosystems by as much as 50%. However, evidence comes largely from experiments that have used highly simplified communities with on average seven species, all from a single trophic group. In contrast, natural communities have dozens, if not hundreds, of species spanning a variety of trophic levels. Would this additional complexity alter our conclusions about the functional consequences of diversity loss? This chapter reviews five hypotheses about how the fluxes of energy and matter through food-webs might depend on the diversity of species interacting within, as well as across trophic levels. After outlining the empirical support for or against each hypothesis, this chapter discusses several avenues of research that may prove useful as ecologists move towards a food web perspective on biodiversity and ecosystem functioning
Biodiversity as spatial insurance: the effects of habitat fragmentation and dispersal on ecosystem functioning
Authors: Gonzalez Andrew , Mouquet Nicolas , Loreau Michel 
Published: September 2009

AbstractHabitat destruction and fragmentation is driving biodiversity loss at local and regional scales, yet the functional effects of this loss are poorly understood. Here, this chapter reviews several concepts that allow us to link local and regional scales of biodiversity and ecosystem functioning. First it shows how the species-area relationship can link loss of habitat to delayed loss of diversity and ecosystem functioning in remnant fragments. Second, it shows that non-linear averaging can be used to estimate the impact of spatial variance in biodiversity caused by fragmentation. Finally the chapter uses a metacommunity framework to formalize the spatial insurance hypothesis. This hypothesis suggests that dispersal is a key process linking diversity to productivity and stability across fragmented landscapes. The theory this chapter outlines stresses that the knowledge of spatial processes across ecosystems will be essential if we are to understand how habitat fragmentation mediates the ecological and economic impacts of biodiversity loss.
Managed ecosystems: biodiversity and ecosystem functions in landscapes modified by human use
Authors: Jackson Louise , Rosenstock Todd , Thomas Matthew , Wright Justin , Symstad Amy 
Published: September 2009

AbstractThis 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.
Biodiversity and ecosystem function: perspectives on disease
Authors: Ostfeld Richard S. , Thomas Matthew , Keesing Felicia 
Published: September 2009

AbstractThe effects of variation in biodiversity on transmission and risk of infectious disease have been conspicuously absent from the biodiversity-ecosystem function (BEF) debates. This chapter addresses several key issues in the BEF literature as they pertain to infectious diseases, including: (1) the shape of the association between biodiversity and disease risk; (2) the relative importance of species richness versus species composition; (3) the relative importance of species richness versus diversity of functional groups or relevant life-history traits; (4) how natural sequences of species loss under environmental change (community disassembly) vs random sequences imposed experimentally influence disease risk; and (5) the importance of diversity at organizational levels other than (host) species in influencing disease risk. In a world where biodiversity is changing dramatically and infectious diseases are emerging and resurging, understanding the role of biodiversity in the ecology of diseases is arguably one of the most important areas in BEF research.
Opening communities to colonization – the impacts of invaders on biodiversity and ecosystem functioning
Authors: Engelhardt Katharina , Symstad Amy , Prieur-Richard Anne-Helene , Thomas Matthew , Bunker Daniel E. 
Published: September 2009

AbstractResearch on the relationship between biodiversity and ecosystem functioning typically varies biodiversity levels by establishing communities that are subsets of the species in the high diversity community. This chapter examines what happens when biodiversity change is not limited to these subsets but instead is open to colonization from a larger species pool. The chapter first examines species traits that are responsible for successful colonization, establishment, and impact on ecosystem processes. The chapter then addresses how novel species may produce cascading and irreversible effects, drawing on known processes (selection effect or complementarity effect) that drive relationships between biodiversity and ecosystem functioning. Finally, the chapter explores how information on species traits and processes driving the relationship between biodiversity and ecosystem functioning may be used to enhance the economic evaluation of invasion risks to society.
Modelling biodiversity and ecosystem services in coupled ecological–economic systems
Authors: Brock William A. , Finnoff David , Kinzig Ann P. , Pascual Unai , Perrings Charles , Tschirhart John , Xepapadeas Anastasios 
Published: September 2009

AbstractThis chapter considers how economists model biodiversity in coupled social ecological systems, taking two polar cases along with a more general problem. Economists assume that all human decisions are purposive: people are assumed to optimize some objective function subject to some set of initial conditions, to some set of resource constraints, and to the dynamics of the system being used. The chapter considers two polar cases and one intermediate case. One polar case involves the preservation of wilderness areas or protected parks in 'close to natural' states. A second involves the exploitation of ecosystems to produce foods, fuels and fibers. The intermediate case involves the management of ecosystems to achieve a balance between non-consumptive cultural services with consumptive provisioning services. While the constrained optimization technique applied in all three cases may be unfamiliar, the chapter tries to give the intuition behind it. It also provides a verbal description of each of the three model structures developed. In all cases the social and biogeophysical components of the coupled system are interdependent — connected through a series of feedback loops. Economists refer to such systems as 'general equilibrium systems'. That is, the dynamics of the system in some state are driven by a tendency towards the equilibrium corresponding to that state, and any perturbation has the potential to stimulate responses across the system.
TraitNet: furthering biodiversity research through the curation, discovery, and sharing of species trait data
Authors: Naeem Shahid , Bunker Daniel E. 
Published: September 2009

AbstractFunctional diversity plays a central role in understanding and predicting the effects of biodiversity on ecosystem functioning precisely because functional traits are the means by which species perform ecosystem functions. While species diversity is easily quantified, functional trait data are often lacking. This chapter describes TraitNet, a US NSF-funded Research Coordination Network dedicated to the advancement of trait-based evolutionary and ecological research. TraitNet's five primary goals are: (1) identify core hypotheses in trait-based research, (2) identify critical data gaps, (3) standardize the collection and curation of trait data, (4) build a model trait database, and (5) facilitate the development of cross-disciplinary ecoinformatic tools for curating and sharing trait data. This coordinated effort will usher in a new era in biodiversity and ecosystem functioning research that will complement existing experimental approaches and provide means for scaling results from individuals to ecosystems.
Can we predict the effects of global change on biodiversity loss and ecosystem functioning?
Authors: Naeem Shahid , E. Bunker Daniel , Hector Andy , Loreau Michel , Perrings Charles 
Published: September 2009

AbstractThe efficacy and practicability of an idea, and the will of individuals or society to explore it, determine whether it catalyzes change or merely enters the vast store of quiescent ideas that make up the bulk of humanity's collective wisdom. The idea that biodiversity influences ecosystem functioning is not new. As in all science, there remain differences among researchers on the interpretation of biodiversity and ecosystem functioning research, but the efficacy of the idea that the diversity of life, not just its mass, influences both the biogeochemical and biotic properties of ecosystems, is well established. This chapter looks across the many contributions in this book and considers a few messages the current field of biodiversity and ecosystem functioning research give us concerning efficacy, practicability, and societal will.
The earliest fossil record of the animals and its significance
Authors: Budd Graham E. 
Published: September 2009

AbstractThe fossil record of the earliest animals has been enlivened in recent years by a series of spectacular discoveries, including embryos, from the Ediacaran to the Cambrian, but many issues, not least of dating and interpretation, remain controversial. In particular, aspects of taphonomy of the earliest fossils require careful consideration before pronouncements about their affinities. Nevertheless, a reasonable case can be now made for the extension of the fossil record of at least basal animals (sponges and perhaps cnidarians) to a period of time significantly before the beginning of the Cambrian. The Cambrian explosion itself still seems to represent the arrival of the bilaterians, and many new fossils in recent years have added significant data on the origin of the three major bilaterian clades. Why animals appear so late in the fossil record is still unclear, but the recent trend to embrace rising oxygen levels as being the proximate cause remains unproven and may even involve a degree of circularity.
Assembling the spiralian tree of life
Authors: Giribet Gonzalo , Dunn Casey W. , Edgecombe Gregory D. , Hejnol Andreas , Martindale Mark Q. , Rouse Greg W. 
Published: September 2009

AbstractThe advent of numerical methods for analyzing phylogenetic relationships, along with the study of morphology and molecular data, have driven our understanding of animal relationships for the past three decades. Within the protostome branch of the animal tree of life, these data have sufficed to establish two major clades; Ecdysozoa, a clade of animals that all moult, and Spiralia (often called Lophotrochozoa), a clade whose most recent common ancestor had spiral cleavage. In this chapter, we outline the current knowledge of protostome relationships and discuss future perspectives and strategies to increase our understanding of relationships within the main spiralian clades. Novel approaches to coding morphological characters are a pressing concern, best dealt with by scoring real observations on species selected as terminals. Methodological issues, such as the treatment of inapplicable characters and the coding of absences, may require novel algorithmic developments. Taxon sampling is another pressing issue, as terminals within phyla should include enough species to represent their span of anatomical disparity. Furthermore, key fossil taxa that can contribute novel character state combinations, such as the so-called 'stem-group lophotrochozoans', should not be neglected. In the molecular forum, EST-based phylogenomics is playing an increasingly important role in elucidating animal relationships. Large-scale sequencing has recently exploded for Spiralia, and phylogenomic data are lacking from only a few phyla, including the three most recently discovered animal phyla (Cycliophora, Loricifera, and Micrognathozoa). While the relationships between many groups now find strong support, others require additional information to be positioned with confidence. Novel morphological observations and phylogenomic data will be critical to resolving these remaining questions. Recent EST-based analyses underpin a new taxonomic proposal, Kryptrochozoa (the least inclusive clade containing the Brachiopoda and Nemertea).
The origins and evolution of the Ecdysozoa
Authors: Telford Maximilian J. , Bourlat Sarah J. , Economou Andrew , Papillon Daniel , Rota-Stabelli Omar 
Published: September 2009

AbstractEcdysozoa is a clade composed of eight phyla, three of which — arthropods, tardigrades, and onychophorans — share segmentation and have appendages, and the remaining five — nematodes, nematomorphs, priapulids, kinorhynchs, and loriciferans — are worms with an anterior proboscis or introvert. Ecdysozoa contains the vast majority of animal species and there is a great diversity of body plans among both living and fossil members. The monophyly of the clade has been called into question by some workers based on analyses of whole genome datasets and we review the evidence that now conclusively supports the unique origin of these phyla. Relationships within Ecdysozoa are also controversial and we discuss the molecular and morphological evidence for several monophyletic groups within this superphylum.
Deciphering deuterostome phylogeny: molecular, morphological, and palaeontological perspectives
Authors: Smith Andrew B. , Swalla Billie J. 
Published: September 2009

AbstractDeuterostomes are a monophyletic group of animals that include the vertebrates, invertebrate chordates, ambulacrarians, and xenoturbellids. Fossil representatives from most major deuterostome groups are found in the Lower Cambrian, suggesting that evolutionary divergence occurred in the late pre-Cambrian, in agreement with molecular clocks. Molecular phylogenies, larval morphology, and the adult heart/kidney complex all support echinoderms and hemichordates as a sister grouping (Ambulacraria). Xenoturbellids represent a relatively newly identified deuterostome phylum that lacks a fossil record, but molecular evidence suggests that these animals are a sister group to the Ambulacraria. Within the chordates, lancelets share large stretches of chromosomal synteny with the vertebrates, have an intact Hox complex and are sister group to the vertebrates according to ribosomal and mitochondrial gene evidence. In contrast, tunicates have a highly derived adult body plan and are sister group to the vertebrates by phylogenetic trees constructed from concatenated genomic sequences. Lancelets and hemichordates share gill slits and an acellular cartilage, suggesting that the ancestral deuterostome also shared these features. Gene network data suggests that the deuterostome ancestor had an A-P axis specified by Hox and Wnt genes, a D-V axis specified by a BMP/chordin gradient, and a L-R asymmetry determined by expression of nodal.
Molecular genetic insights into deuterostome evolution from the direct-developing hemichordateSaccoglossus kowalevskii
Authors: Lowe Christopher J. 
Published: September 2009

AbstractProgress in developmental biology, phylogenomics, and palaeontology over the past five years has made major contributions to a long-enduring problem in comparative biology: the early origins of the deuterostome phyla. A detailed characterization of the early development of the enteropneust hemichordate, Saccoglossus kowalevskii, revealed close developmental genetic similarities between hemichordates and chordates during early body plan formation. The two phyla share close transcriptional and signaling ligand expression patterns during the early development of the anteroposterior and dorsoventral axes, despite large morphological disparity between the body plans. These genetic networks have been proposed to play conserved roles in patterning centralized nervous systems in metazoans, yet likely play conserved roles in patterning the diffusely organized basiepithelial nerve net of the hemichordates. Developmental genetic data are providing a unique insight into early deuterostome evolution, revealing a complexity of genetic regulation previously attributed only to vertebrates. Although these data allow for key insights into the development of early deuterostomes, their utility for reconstructing ancestral morphologies is less certain; morphological, palaeontological and molecular datasets should all be considered carefully when speculating about ancestral deuterostome features.
Invertebrate Problematica: kinds, causes, and solutions
Authors: Jenner Ronald A. , Timothy D. , Littlewood J. 
Published: September 2009

AbstractProblematica are taxa that defy robust phylogenetic placement. Traditionally the term was restricted to fossil forms, but it is clear that extant taxa may be just as difficult to place, whether using morphological or molecular (nucleotide, gene, or genomic) markers for phylogeny reconstruction. This chapter discusses the kinds and causes of Problematica within the Metazoa, but particularly focussing on the invertyebrate taxa, as well as suggesting criteria for their recognition and possible solutions. The inclusive set of Problematica changes depending upon the nature and quality of (homologous) data available, the methods of phylogeny reconstruction and the sister taxa inferred by their placement or displacement. Rather than excluding Problematica from phylogeny reconstruction, as has often been preferred, this chapter concludes that the study of Problematica is crucial both for the resolution of metazoan phylogeny, and the proper inference of body plan evolution. This chapter provides an annotated list of key extant problematic taxa.
Improvement of molecular phylogenetic inference and the phylogeny of Bilateria
Authors: Lartillot Nicolas , Philippe Hervé 
Published: September 2009

AbstractInferring the relationships among Bilateria has been an active and controversial research area since Haeckel. The lack of a sufficient number of phylogenetically reliable characters was the main limitation of traditional phylogenies based on morphology. With the advent of molecular data, this problem has been replaced by another, statistical inconsistency, which stems from an erroneous interpretation of convergences induced by multiple changes. The analysis of alignments rich in both genes and species, combined with a probabilistic method (Maximum Likelihood or Bayesian) using sophisticated models of sequence evolution, should alleviate these two major limitations. This chapter applies this approach to a dataset of 94 genes from 79 species using the CAT model, which accounts for site-specific amino-acid replacement patterns. The resulting tree is in good agreement with current knowledge: the monophyly of most major groups (e.g. Chordata, Arthropoda, Lophotrochozoa, Ecdysozoa, Protostomia) was recovered with high support. Two results are surprising and are discussed in an evo-devo framework: the sister-group relationship of Platyhelminthes and Annelida to the exclusion of Mollusca, contradicting the Neotrochozoa hypothesis, and, with a lower statistical support, the paraphyly of Deuterostomia. These results, in particular the status of deuterostomes, need further confirmation, both through increased taxonomic sampling, and future improvements of probabilistic models.
The evolution of developmental gene networks: lessons from comparative studies on holometabolous insects
Authors: Peel Andrew D. 
Published: September 2009

AbstractRecent comparative studies have revealed significant differences in the developmental gene networks operating in three holometabolous insects: the beetle Tribolium castaneum, the parasitic wasp Nasonia vitripennis and the fruit fly Drosophila melanogaster. This chapter discusses these differences in relation to divergent and convergent changes in cellular embryology. This chapter speculates on how segmentation gene networks could have evolved to operate in divergent embryological contexts, and highlight the role co-option might have played in this process. This chapter argues that insects represent an important example of how diversification in life history strategies between lineages can lead to divergence in the genetic and cellular mechanisms controlling the development of homologous adult structures
Conserved developmental processes and the evolution of novel traits: wounds, embryos, veins, and butterfly eyespots
Authors: Beldade Patrícia , Saenko Suzanne V. 
Published: September 2009

AbstractThe origin and diversification of morphological novelties is a key issue in evolutionary developmental biology. Possibilities for comparative analysis of the genetic and developmental bases of such lineage-specific traits, however, can be limited when they have no obvious homolog in model organisms. The finding that the evolution of morphological innovations often involves the recruitment of pre-existing genes and/or gene networks offers the potential to overcome this challenge. Knowledge about shared developmental processes from studies in model organisms can then be used to understand the origin and diversification of traits represented only in other lineages. This chapter illustrates this approach in relation to butterfly eyespots using examples from the tractable laboratory system Bicyclus anynana. This chapter discusses experimental data exploring genetic commonalities between eyespot patterning and three different conserved developmental processes; wound healing, embryonic development, and wing vein formation. Analyzing such well-described processes in the context of eyespot development holds great promise for furthering our understanding of those lepidopteran-specific and highly diverse morphological traits.
3 Risk Management and Institutional Investors
Authors: Clark Gordon L. 
Published: September 2009

AbstractThis chapter examines the governance of institutional investors, notably pension and retirement income funds. As most nation-states have abandoned quantitative and qualitative restrictions on cross-border investment for pension funds and insurance companies, these institutions have increasingly operated on a global scale. As such, these institutions are consigned to manage their financial risk while following their implicit or explicit mandates to maximize the rate of return on investments. Yet, just as the macro-level governance of financial markets is problematic, the chapter notes that institutional governance is more often than not imperfect and subject to problems of coordination. As such, the chapter provides an account of the nature and scope of financial decision-making under conditions of risk and uncertainty, demonstrating the importance of time, expertise, and collective commitment in the decision ecologies of these types of institutions. Understanding the dynamics and structure of decision-making in these institutions is a necessary ingredient to any comprehensive understanding of the logic of global financial markets.