ORCID Profile
0000-0001-9687-0593
Current Organisation
University of St Andrews
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Publisher: Springer Science and Business Media LLC
Date: 16-03-2023
DOI: 10.1038/S41467-023-37127-2
Abstract: While human activities are known to elicit rapid turnover in species composition through time, the properties of the species that increase or decrease their spatial occupancy underlying this turnover are less clear. Here, we used an extensive dataset of 238 metacommunity time series of multiple taxa spread across the globe to evaluate whether species that are more widespread (large-ranged species) differed in how they changed their site occupancy over the 10–90 years the metacommunities were monitored relative to species that are more narrowly distributed (small-ranged species). We found that on average, large-ranged species tended to increase in occupancy through time, whereas small-ranged species tended to decrease. These relationships were stronger in marine than in terrestrial and freshwater realms. However, in terrestrial regions, the directional changes in occupancy were less extreme in protected areas. Our findings provide evidence for systematic decreases in occupancy of small-ranged species, and that habitat protection could mitigate these losses in the face of environmental change.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-09-2023
Publisher: American Association for the Advancement of Science (AAAS)
Date: 18-10-2019
Abstract: Bio ersity is undergoing rapid change driven by climate change and other human influences. Blowes et al. analyze the global patterns in temporal change in bio ersity using a large quantity of time-series data from different regions (see the Perspective by Eriksson and Hillebrand). Their findings reveal clear spatial patterns in richness and composition change, where marine taxa exhibit the highest rates of change. The marine tropics, in particular, emerge as hotspots of species richness losses. Given that human activities are affecting bio ersity in magnitudes and directions that differ across the planet, these findings will provide a much needed biogeographic understanding of bio ersity change that can help inform conservation prioritization. Science , this issue p. 339 see also p. 308
Publisher: Wiley
Date: 15-03-2019
DOI: 10.1111/ELE.13242
Abstract: Scientists disagree about the nature of bio ersity change. While there is evidence for widespread declines from population surveys, assemblage surveys reveal a mix of declines and increases. These conflicting conclusions may be caused by the use of different metrics: assemblage metrics may average out drastic changes in in idual populations. Alternatively, differences may arise from data sources: populations monitored in idually, versus whole-assemblage monitoring. To test these hypotheses, we estimated population change metrics using assemblage data. For a set of 23 241 populations, 16 009 species, in 158 assemblages, we detected significantly accelerating extinction and colonisation rates, with both rates being approximately balanced. Most populations (85%) did not show significant trends in abundance, and those that did were balanced between winners (8%) and losers (7%). Thus, population metrics estimated with assemblage data are commensurate with assemblage metrics and reveal sustained and increasing species turnover.
Publisher: Wiley
Date: 24-08-2021
Abstract: Bio ersity is a multifaceted concept covering different levels of organization from genes to ecosystems. Bio ersity has at least three dimensions: (a) Taxonomic ersity (TD): a measure that is sensitive to the number and abundances of species. (b) Phylogenetic ersity (PD): a measure that incorporates not only species abundances but also species evolutionary histories. (c) Functional ersity (FD): a measure that considers not only species abundances but also species' traits. We integrate the three dimensions of ersity 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 ided by tree depth) quantifies the effective number of equally ergent 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 s ling data depend on s ling effort and s le completeness. For TD (Hill numbers), the iNEXT (interpolation and extrapolation) standardization was developed for standardizing s le size or s le completeness (as measured by s le coverage, the fraction of in iduals 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 ersity via s le size‐ and s le coverage‐based rarefaction and extrapolation under the unified framework. The asymptotic ersity estimates (i.e. s le size tends to infinity and s le coverage tends to unity) are also derived. In addition to in idual‐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‐ ersity changes for estuarine fish assemblage data spanning four decades. The influence of environmental drivers on ersity change are also assessed. Our analysis informs a mechanistic interpretation of bio ersity change in the three dimensions of ersity. The accompanying freeware, iNEXT.3D, developed during this project, facilitates all computation and graphics.
Publisher: Wiley
Date: 10-11-2019
DOI: 10.1111/GEB.13026
Publisher: Springer Science and Business Media LLC
Date: 24-09-2015
DOI: 10.1038/NCOMMS9405
Abstract: The role human activities play in reshaping bio ersity is increasingly apparent in terrestrial ecosystems. However, the responses of entire marine assemblages are not well-understood, in part, because few monitoring programs incorporate both spatial and temporal replication. Here, we analyse an exceptionally comprehensive 29-year time series of North Atlantic groundfish assemblages monitored over 5° latitude to the west of Scotland. These fish assemblages show no systematic change in species richness through time, but steady change in species composition, leading to an increase in spatial homogenization: the species identity of colder northern localities increasingly resembles that of warmer southern localities. This biotic homogenization mirrors the spatial pattern of unevenly rising ocean temperatures over the same time period suggesting that climate change is primarily responsible for the spatial homogenization we observe. In this and other ecosystems, apparent constancy in species richness may mask major changes in species composition driven by anthropogenic change.
Publisher: Wiley
Date: 24-09-2023
DOI: 10.1002/ECM.1588
Abstract: Based on s ling data, we propose a rigorous standardization method to measure and compare beta ersity across datasets. Here beta ersity, which quantifies the extent of among‐assemblage differentiation, relies on Whittaker's original multiplicative decomposition scheme, but we use Hill numbers for any ersity order q ≥ 0. Richness‐based beta ersity ( q = 0) quantifies the extent of species identity shift, whereas abundance‐based ( q 0) beta ersity also quantifies the extent of difference among assemblages in species abundance. We adopt and define the assumptions of a statistical s ling‐model as the foundation for our approach, treating s ling data as a representative s le taken from an assemblage. The approach makes a clear distinction between the theoretical assemblage level (unknown properties arameters of the assemblage) and the s ling data level (empirical/observed statistics computed from data). At the assemblage level, beta ersity for N assemblages reflects the interacting effect of the species abundance distribution and spatial/temporal aggregation of in iduals in the assemblage. At the data level, observed beta (= gamma/alpha) ersity depends not only on among‐assemblage differentiation but also on s ling effort/completeness, which in turn induces dependence of beta on alpha and gamma ersity. How to remove the dependence of richness‐based beta ersity on its gamma component (species pool) has been intensely debated. Our approach is to standardize gamma and alpha based on s le coverage (an objective measure of s le completeness). For a single assemblage, the iNEXT method was developed, through interpolation (rarefaction) and extrapolation with Hill numbers, to standardize s les by s ling effort/completeness. Here we adapt the iNEXT standardization to alpha and gamma ersity, i.e., alpha and gamma ersity are both assessed at the same level of s le coverage, to formulate standardized, coverage‐based beta ersity. This extension of iNEXT to beta ersity required the development of novel concepts and theories, including a formal proof and empirical demonstration that the resulting standardized beta ersity removes the dependence of beta ersity on both gamma and alpha values, and thus reflects the pure among‐assemblage differentiation. The proposed standardization is illustrated with spatial, temporal and spatio‐temporal datasets, while the freeware iNEXT.beta3D facilitates all computations and graphics. This article is protected by copyright. All rights reserved.
Publisher: Proceedings of the National Academy of Sciences
Date: 12-02-2018
Abstract: The Earth’s ecosystems are under unprecedented pressure, yet the nature of contemporary bio ersity change is not well understood. Growing evidence that community size is regulated highlights the need for improved understanding of community dynamics. As stability in community size could be underpinned by marked temporal turnover, a key question is the extent to which changes in both bio ersity dimensions (temporal α- and temporal β- ersity) covary within and among the assemblages that comprise natural communities. Here, we draw on a multiassemblage dataset (encompassing vertebrates, invertebrates, and unicellular plants) from a tropical freshwater ecosystem and employ a cyclic shift randomization to assess whether any directional change in temporal α- ersity and temporal β- ersity exceeds baseline levels. In the majority of cases, α- ersity remains stable over the 5-y time frame of our analysis, with little evidence for systematic change at the community level. In contrast, temporal β- ersity changes are more prevalent, and the two ersity dimensions are decoupled at both the within- and among-assemblage level. Consequently, a pressing research challenge is to establish how turnover supports regulation and when elevated temporal β- ersity jeopardizes community integrity.
Publisher: Wiley
Date: 03-11-2021
DOI: 10.1111/GCB.15947
Abstract: The species composition of plant and animal assemblages across the globe has changed substantially over the past century. How do the dynamics of in idual species cause this change? We classified species into seven unique categories of temporal dynamics based on the ordered sequence of presences and absences that each species contributes to an assemblage time series. We applied this framework to 14,434 species trajectories comprising 280 assemblages of temperate marine fishes surveyed annually for 20 or more years. Although 90% of the assemblages erged in species composition from the baseline year, this compositional change was largely driven by only 8% of the species' trajectories. Quantifying the reorganization of assemblages based on species shared temporal dynamics should facilitate the task of monitoring and restoring bio ersity. We suggest ways in which our framework could provide informative measures of compositional change, as well as leverage future research on pattern and process in ecological systems.
Publisher: The Royal Society
Date: 10-05-2023
Abstract: Alien species are widely linked to bio ersity change, but the extent to which they are associated with the reshaping of ecological communities is not well understood. One possible mechanism is that assemblages where alien species are found exhibit elevated temporal turnover. To test this, we identified assemblages of vascular plants in the BioTIME database for those assemblages in which alien species are either present or absent and used the Jaccard measure to compute compositional dissimilarity between consecutive censuses. We found that, although alien species are typically rare in invaded assemblages, their presence is associated with an increase in the average rate of compositional change. These differences in compositional change between invaded and uninvaded assemblages are not linked to differences in species richness but rather to species replacement (turnover). Rapid compositional restructuring of assemblages is a major contributor to bio ersity change, and as such, our results suggest a role for alien species in bringing this about.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 18-04-2014
Abstract: Although the rate of species extinction has increased markedly as a result of human activity across the biosphere, conservation has focused on endangered species rather than on shifts in assemblages. Dornelas et al. (p. 296 see the Perspective by Pandolfi and Lovelock ), using an extensive set of bio ersity time series of species occurrences in both marine and terrestrial habitats from the past 150 years, find species turnover above expected but do not find evidence of systematic bio ersity loss. This result could be caused by homogenization of species assemblages by invasive species, shifting distributions induced by climate change, and asynchronous change across the planet. All of which indicates that it is time to review conservation priorities.
Publisher: Wiley
Date: 07-2018
DOI: 10.1111/GEB.12729
Publisher: The Royal Society
Date: 29-05-2023
Abstract: Estimating bio ersity change across the planet in the context of widespread human modification is a critical challenge. Here, we review how bio ersity has changed in recent decades across scales and taxonomic groups, focusing on four ersity metrics: species richness, temporal turnover, spatial beta- ersity and abundance. At local scales, change across all metrics includes many ex les of both increases and declines and tends to be centred around zero, but with higher prevalence of declining trends in beta- ersity (increasing similarity in composition across space or biotic homogenization) and abundance. The exception to this pattern is temporal turnover, with changes in species composition through time observed in most local assemblages. Less is known about change at regional scales, although several studies suggest that increases in richness are more prevalent than declines. Change at the global scale is the hardest to estimate accurately, but most studies suggest extinction rates are probably outpacing speciation rates, although both are elevated. Recognizing this variability is essential to accurately portray how bio ersity change is unfolding, and highlights how much remains unknown about the magnitude and direction of multiple bio ersity metrics at different scales. Reducing these blind spots is essential to allow appropriate management actions to be deployed. This article is part of the theme issue ‘Detecting and attributing the causes of bio ersity change: needs, gaps and solutions’.
Publisher: Wiley
Date: 09-01-2017
DOI: 10.1002/ECY.1660
Abstract: We present new data and analyses revealing fundamental flaws in a critique of two recent meta-analyses of local-scale temporal bio ersity change. First, the conclusion that short-term time series lead to biased estimates of long-term change was based on two errors in the simulations used to support it. Second, the conclusion of negative relationships between temporal bio ersity change and study duration was entirely dependent on unrealistic model assumptions, the use of a subset of data, and inclusion of one outlier data point in one study. Third, the finding of a decline in local bio ersity, after eliminating post-disturbance studies, is not robust to alternative analyses on the original data set, and is absent in a larger, updated data set. Finally, the undebatable point, noted in both original papers, that studies in the ecological literature are geographically biased, was used to cast doubt on the conclusion that, outside of areas converted to croplands or asphalt, the distribution of bio ersity trends is centered approximately on zero. Future studies may modify conclusions, but at present, alternative conclusions based on the geographic-bias argument rely on speculation. In sum, the critique raises points of uncertainty typical of all ecological studies, but does not provide an evidence-based alternative interpretation.
Publisher: Cold Spring Harbor Laboratory
Date: 03-02-2023
DOI: 10.1101/2023.02.03.526822
Abstract: Biotic responses to global change include directional shifts in organismal traits. Body size, an integrative trait that determines demographic rates and ecosystem functions, is often thought to be shrinking in the Anthropocene. Here, we assess the prevalence of body size change in six taxon groups across 5,032 assemblage time-series spanning 1960-2020. Using the Price equation to partition this change into within-species body size versus compositional changes, we detect prevailing decreases in body size through time. Change in assemblage composition contributes more to body size changes than within-species trends, but both components show substantial variation in magnitude and direction. The biomass of assemblages remains remarkably stable as decreases in body size trade-off with increases in abundance. Variable within-species and compositional trends combine into shrinking body size, abundance increases and stable biomass.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 07-07-2017
Abstract: Temporal fluctuations in species richness are frequently regulated, exhibiting a tendency to return toward a central level.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Faye Helen Moyes.