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  • Henderson, Peter A.  (7)
  • 1
    In: Methods in Ecology and Evolution, Wiley, Vol. 12, No. 10 ( 2021-10), p. 1926-1940
    Abstract: Biodiversity is a multifaceted concept covering different levels of organization from genes to ecosystems. Biodiversity has at least three dimensions: (a) Taxonomic diversity (TD): a measure that is sensitive to the number and abundances of species. (b) Phylogenetic diversity (PD): a measure that incorporates not only species abundances but also species evolutionary histories. (c) Functional diversity (FD): a measure that considers not only species abundances but also species' traits. We integrate the three dimensions of diversity under a unified framework of Hill numbers and their generalizations. Our TD quantifies the effective number of equally abundant species, PD quantifies the effective total branch length, mean‐PD (PD divided by tree depth) quantifies the effective number of equally divergent lineages, and FD quantifies the effective number of equally distinct virtual functional groups (or functional ‘species’). Thus, TD, mean‐PD and FD are all in the same units of species/lineage equivalents and can be meaningfully compared. Like species richness, empirical TD, PD and FD based on sampling data depend on sampling effort and sample completeness. For TD (Hill numbers), the iNEXT (interpolation and extrapolation) standardization was developed for standardizing sample size or sample completeness (as measured by sample coverage, the fraction of individuals that belong to the observed species) to make objective comparisons across studies. This paper extends the iNEXT method to the iNEXT.3D standardization to encompass all three dimensions of diversity via sample size‐ and sample coverage‐based rarefaction and extrapolation under the unified framework. The asymptotic diversity estimates (i.e. sample size tends to infinity and sample coverage tends to unity) are also derived. In addition to individual‐based abundance data, the proposed iNEXT.3D standardization is adapted to deal with incidence‐based occurrence data. We apply the integrative framework and the proposed iNEXT.3D standardization to measure temporal alpha‐diversity changes for estuarine fish assemblage data spanning four decades. The influence of environmental drivers on diversity change are also assessed. Our analysis informs a mechanistic interpretation of biodiversity change in the three dimensions of diversity. The accompanying freeware, iNEXT.3D, developed during this project, facilitates all computation and graphics.
    Type of Medium: Online Resource
    ISSN: 2041-210X , 2041-210X
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2528492-7
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  • 2
    Online Resource
    Online Resource
    The Royal Society ; 2010
    In:  Philosophical Transactions of the Royal Society B: Biological Sciences Vol. 365, No. 1558 ( 2010-11-27), p. 3611-3620
    In: Philosophical Transactions of the Royal Society B: Biological Sciences, The Royal Society, Vol. 365, No. 1558 ( 2010-11-27), p. 3611-3620
    Abstract: Temporal variation in species abundances occurs in all ecological communities. Here, we explore the role that this temporal turnover plays in maintaining assemblage diversity. We investigate a three-decade time series of estuarine fishes and show that the abundances of the individual species fluctuate asynchronously around their mean levels. We then use a time-series modelling approach to examine the consequences of different patterns of turnover, by asking how the correlation between the abundance of a species in a given year and its abundance in the previous year influences the structure of the overall assemblage. Classical diversity measures that ignore species identities reveal that the observed assemblage structure will persist under all but the most extreme conditions. However, metrics that track species identities indicate a narrower set of turnover scenarios under which the predicted assemblage resembles the natural one. Our study suggests that species diversity metrics are insensitive to change and that measures that track species ranks may provide better early warning that an assemblage is being perturbed. It also highlights the need to incorporate temporal turnover in investigations of assemblage structure and function.
    Type of Medium: Online Resource
    ISSN: 0962-8436 , 1471-2970
    RVK:
    Language: English
    Publisher: The Royal Society
    Publication Date: 2010
    detail.hit.zdb_id: 1462620-2
    SSG: 12
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  • 3
    Online Resource
    Online Resource
    The Royal Society ; 2010
    In:  Proceedings of the Royal Society B: Biological Sciences Vol. 277, No. 1687 ( 2010-05-22), p. 1561-1570
    In: Proceedings of the Royal Society B: Biological Sciences, The Royal Society, Vol. 277, No. 1687 ( 2010-05-22), p. 1561-1570
    Abstract: Species abundance distributions (SADs) are widely used as a tool for summarizing ecological communities but may have different shapes, depending on the currency used to measure species importance. We develop a simple plotting method that links SADs in the alternative currencies of numerical abundance and biomass and is underpinned by testable predictions about how organisms occupy physical space. When log numerical abundance is plotted against log biomass, the species lie within an approximately triangular region. Simple energetic and sampling constraints explain the triangular form. The dispersion of species within this triangle is the key to understanding why SADs of numerical abundance and biomass can differ. Given regular or random species dispersion, we can predict the shape of the SAD for both currencies under a variety of sampling regimes. We argue that this dispersion pattern will lie between regular and random for the following reasons. First, regular dispersion patterns will result if communities are comprised groups of organisms that use different components of the physical space (e.g. open water, the sea bed surface or rock crevices in a marine fish assemblage), and if the abundance of species in each of these spatial guilds is linked to the way individuals of varying size use the habitat. Second, temporal variation in abundance and sampling error will tend to randomize this regular pattern. Data from two intensively studied marine ecosystems offer empirical support for these predictions. Our approach also has application in environmental monitoring and the recognition of anthropogenic disturbance, which may change the shape of the triangular region by, for example, the loss of large body size top predators that occur at low abundance.
    Type of Medium: Online Resource
    ISSN: 0962-8452 , 1471-2954
    Language: English
    Publisher: The Royal Society
    Publication Date: 2010
    detail.hit.zdb_id: 1460975-7
    SSG: 12
    SSG: 25
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  • 4
    Online Resource
    Online Resource
    The Royal Society ; 2014
    In:  Proceedings of the Royal Society B: Biological Sciences Vol. 281, No. 1791 ( 2014-09-22), p. 20141336-
    In: Proceedings of the Royal Society B: Biological Sciences, The Royal Society, Vol. 281, No. 1791 ( 2014-09-22), p. 20141336-
    Abstract: To understand how ecosystems are structured and stabilized, and to identify when communities are at risk of damage or collapse, we need to know how the abundances of the taxa in the entire assemblage vary over ecologically meaningful timescales. Here, we present an analysis of species temporal variability within a single large vertebrate community. Using an exceptionally complete 33-year monthly time series following the dynamics of 81 species of fishes, we show that the most abundant species are least variable in terms of temporal biomass, because they are under density-dependent (negative feedback) regulation. At the other extreme, a relatively large number of low abundance transient species exhibit the greatest population variability. The high stability of the consistently common high abundance species—a result of density-dependence—is reflected in the observation that they consistently represent over 98% of total fish biomass. This leads to steady ecosystem nutrient and energy flux irrespective of the changes in species number and abundance among the large number of low abundance transient species. While the density-dependence of the core species ensures stability under the existing environmental regime, the pool of transient species may support long-term stability by replacing core species should environmental conditions change.
    Type of Medium: Online Resource
    ISSN: 0962-8452 , 1471-2954
    Language: English
    Publisher: The Royal Society
    Publication Date: 2014
    detail.hit.zdb_id: 1460975-7
    SSG: 12
    SSG: 25
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  • 5
    Online Resource
    Online Resource
    Wiley ; 2019
    In:  Global Ecology and Biogeography Vol. 28, No. 12 ( 2019-12), p. 1949-1960
    In: Global Ecology and Biogeography, Wiley, Vol. 28, No. 12 ( 2019-12), p. 1949-1960
    Abstract: Biodiversity change, that is how the taxonomic identities and abundances of species in ecological systems are changing over time, has two facets: temporal α diversity and temporal β diversity. To date, temporal α diversity has received most attention even though compositional shifts in assemblages exceed expectations based on ecological theory. Growing concern about the state of the world’s biodiversity highlights the need for better understanding of the extent, and consequences, of compositional reorganization in ecological systems. Challenges Most methods of measuring β diversity have been developed in a spatial context. We discuss the additional challenges involved in the assessment of temporal change, summarize existing methodological approaches, highlight the importance of establishing relevant baselines, and identify the need for appropriate null models of temporal β diversity. Given considerable potential for research on the macroecology of temporal β diversity we suggest future directions and challenges. Conclusions Although data availability remains the main impediment to improved quantification of temporal β diversity at macroecological scales, there are substantial opportunities for improved methodology and theory. Taxonomic β diversity has received most attention, but other dimensions of diversity, including functional and phylogenetic, should be part of integrated assessments of biodiversity change. Future approaches need to be ecologically meaningful and interpretable as well as statistically robust.
    Type of Medium: Online Resource
    ISSN: 1466-822X , 1466-8238
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 1479787-2
    detail.hit.zdb_id: 2021283-5
    SSG: 12
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  • 6
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 2003
    In:  Nature Vol. 422, No. 6933 ( 2003-4), p. 714-716
    In: Nature, Springer Science and Business Media LLC, Vol. 422, No. 6933 ( 2003-4), p. 714-716
    Type of Medium: Online Resource
    ISSN: 0028-0836 , 1476-4687
    RVK:
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    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2003
    detail.hit.zdb_id: 120714-3
    detail.hit.zdb_id: 1413423-8
    SSG: 11
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  • 7
    Online Resource
    Online Resource
    The Royal Society ; 2012
    In:  Proceedings of the Royal Society B: Biological Sciences Vol. 279, No. 1743 ( 2012-09-22), p. 3722-3726
    In: Proceedings of the Royal Society B: Biological Sciences, The Royal Society, Vol. 279, No. 1743 ( 2012-09-22), p. 3722-3726
    Abstract: How do species divide resources to produce the characteristic species abundance distributions seen in nature? One way to resolve this problem is to examine how the biomass (or capacity) of the spatial guilds that combine to produce an abundance distribution is allocated among species. Here we argue that selection on body size varies across guilds occupying spatially distinct habitats. Using an exceptionally well-characterized estuarine fish community, we show that biomass is concentrated in large bodied species in guilds where habitat structure provides protection from predators, but not in those guilds associated with open habitats and where safety in numbers is a mechanism for reducing predation risk. We further demonstrate that while there is temporal turnover in the abundances and identities of species that comprise these guilds, guild rank order is conserved across our 30-year time series. These results demonstrate that ecological communities are not randomly assembled but can be decomposed into guilds where capacity is predictably allocated among species.
    Type of Medium: Online Resource
    ISSN: 0962-8452 , 1471-2954
    Language: English
    Publisher: The Royal Society
    Publication Date: 2012
    detail.hit.zdb_id: 1460975-7
    SSG: 12
    SSG: 25
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