ORCID Profile
0000-0002-0036-2795
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: Wiley
Date: 12-11-2019
DOI: 10.1111/GEB.13025
Publisher: American Association for the Advancement of Science (AAAS)
Date: 19-06-2020
Abstract: Land-use change by humans, particularly forest loss, is influencing Earth's bio ersity through time. To assess the influence of forest loss on population and bio ersity change, Daskalova et al. integrated data from more than 6000 time series of species' abundance, richness, and composition in ecological assemblages around the world. Forest loss leads to both positive and negative responses of populations and bio ersity, and the temporal lags in population and bio ersity change after forest loss can extend up to half a century. Land-use change precipitates ergent population and bio ersity change. This analysis has consequences for projections of human impact, ongoing conservation, and assessments of bio ersity change. Science , this issue p. 1341
Publisher: Elsevier BV
Date: 04-2003
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: 02-11-2016
DOI: 10.1111/GEB.12532
Publisher: Wiley
Date: 10-11-2019
DOI: 10.1111/GEB.13026
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.TREE.2014.11.006
Abstract: Humans are transforming the biosphere in unprecedented ways, raising the important question of how these impacts are changing bio ersity. Here we argue that our understanding of bio ersity trends in the Anthropocene, and our ability to protect the natural world, is impeded by a failure to consider different types of bio ersity measured at different spatial scales. We propose that ecologists should recognize and assess 15 distinct categories of bio ersity trend. We summarize what is known about each of these 15 categories, identify major gaps in our current knowledge, and recommend the next steps required for better understanding of trends in bio ersity.
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: American Association for the Advancement of Science (AAAS)
Date: 06-06-2014
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: Springer Science and Business Media LLC
Date: 2014
Publisher: Cold Spring Harbor Laboratory
Date: 22-09-2023
Publisher: Springer Science and Business Media LLC
Date: 2012
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-09-2023
Publisher: Springer Science and Business Media LLC
Date: 08-2003
Publisher: Wiley
Date: 06-2006
Publisher: Oxford University Press (OUP)
Date: 12-02-2014
DOI: 10.1111/BIJ.12217
Publisher: Wiley
Date: 16-07-2004
Publisher: Wiley
Date: 05-04-2013
DOI: 10.1111/ETH.12087
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: 12-08-2003
Publisher: Wiley
Date: 12-11-2015
DOI: 10.1002/ECE3.1800
Publisher: Wiley
Date: 14-05-2023
DOI: 10.1111/ELE.14214
Abstract: The composition of ecological assemblages has changed rapidly over the past century. Compositional reorganization rates are high relative to rates of alpha ersity change, creating an urgent need to understand how this compositional reorganization is progressing. We developed a quantitative framework for comparing temporal trajectories of compositional reorganization and applied it to two long‐term bird and marine fish datasets. We then evaluated how the number and magnitude of short‐term changes relate to overall rates of change. We found varied trajectories of turnover across birds and fish, with linear directional change predominating in birds and non‐directional change more common in fish. The number of changes away from the baseline was a more consistent correlate of the overall rate of change than the magnitude of such changes, but large unreversed changes were found in both fish and birds, as were time series with accelerating compositional change. Compositional reorganization is progressing through a complex mix of temporal trajectories, including both threshold‐like behaviour and the accumulation of repeated, linear change.
Publisher: Oxford University Press (OUP)
Date: 19-05-2010
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: 25-01-2019
DOI: 10.1111/ECOG.04117
Publisher: Elsevier BV
Date: 02-2018
Publisher: Elsevier BV
Date: 03-2005
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: The Royal Society
Date: 27-11-2010
Abstract: From the pioneering explorations of Joseph Banks (later a President of the Royal Society), to the present day, a great deal has been learnt about the extent, distribution and stability of biological ersity in the world. We now know that erse life can be found even in the most inhospitable places. We have also learned that biological ersity changes through time over both large and small temporal scales. These natural changes track environmental conditions, and reflect ecological and evolutionary processes. However, anthropogenic activities, including overexploitation, habitat loss and climate change, are currently causing profound transformations in ecosystems and unprecedented loss of biological ersity. This series of papers considers temporal variation in biological ersity, examines the extent of human-related change relative to underlying natural change and builds on these insights to develop tools and policies to help guide us towards a sustainable future.
Publisher: Wiley
Date: 22-03-2019
DOI: 10.1111/ETH.12864
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: Cold Spring Harbor Laboratory
Date: 03-12-2018
DOI: 10.1101/473645
Abstract: Global assessments have highlighted land-use change as a key driver of bio ersity change. However, we lack real-world global-scale estimates of how habitat transformations such as forest loss and gain are reshaping bio ersity over time. Here, we quantify the influence of 150 years of forest cover change on populations and ecological assemblages worldwide and across taxa by analyzing change in 6,667 time series. We found that forest loss simultaneously intensified ongoing increases and decreases in abundance, species richness and temporal species replacement (turnover) by up to 48%. Temporal lags in these responses extended up to 50 years and increased with species’ generation time. Our findings demonstrate that land-use change precipitates ergent population and bio ersity change, highlighting the complex biotic consequences of deforestation and afforestation. Declines in forest cover lify both gains and losses in population abundance and bio ersity over time.
Publisher: Cold Spring Harbor Laboratory
Date: 26-11-2019
DOI: 10.1101/841833
Abstract: Climate change is reshaping global bio ersity as species respond to changing temperatures. However, the net effects of climate-driven species redistribution on local assemblage ersity remain unknown. Here, we relate trends in species richness and abundance from 21,500 terrestrial and marine assemblage time series across temperate regions (23.5-60.0°) to changes in air or sea surface temperature. We find a strong coupling between bio ersity and temperature changes in the marine realm, which is conditional on the baseline climate. We detect increases in species richness with increasing temperature that is twice as pronounced in warmer locations, while abundance declines with warming in the warmest marine locations. In contrast, we did not detect systematic temperature-related richness or abundance trends on land, despite a greater magnitude of warming. We also found no evidence for an interaction between bio ersity change and latitude, further emphasizing the importance of baseline climate in structuring assemblages. As the world is committed to further warming, significant challenges remain in maintaining local bio ersity amongst the non-uniform inflow and outflow of “climate migrants” across distinct regions, especially in the ocean.
Publisher: Springer Science and Business Media LLC
Date: 15-09-2010
Publisher: Elsevier BV
Date: 11-2006
Publisher: The Royal Society
Date: 10-01-2018
Abstract: Variation in predation risk is a major driver of ecological and evolutionary change, and, in turn, of geographical variation in behaviour. While predation risk is rarely constant in natural populations, the extent to which variation in predation risk shapes in idual behaviour in wild populations remains unclear. Here, we investigated in idual differences in reproductive behaviour in 16 Trinidadian guppy populations and related it to the observed variation in predator biomass each population experienced. Our results show that high heterogeneity in predator biomass is linked to in idual behavioural ersification. Increased within-population heterogeneity in predator biomass is also associated with behavioural polymorphism. Some in iduals adjust the frequency of consensual mating behaviour in response to differences in sex ratio context, while others display constantly at elevated frequencies. This pattern is analogous to a ‘live fast, die young’ pace-of-life syndrome. Notably, both high and low mean differences in predator biomass led to a homogenization of in idual frequency of consensual mating displays. Overall, our results demonstrate that in idual behavioural variation is associated with heterogeneity in predator biomass, but not necessarily with changes in mean values of predator biomass. We suggest that heterogeneity in predator biomass is an informative predictor of adaptive responses to changes in biotic conditions.
Publisher: Wiley
Date: 29-09-2022
DOI: 10.1002/ECY.3820
Abstract: Bio ersity metrics often integrate data on the presence and abundance of multiple species. Yet our understanding of covariation between changes to the numbers of in iduals, the evenness of species relative abundances, and the total number of species remains limited. Using in idual‐based rarefaction curves, we show how expected positive relationships among changes in abundance, evenness and richness arise, and how they can break down. We then examined interdependencies between changes in abundance, evenness and richness in more than 1100 assemblages s led either through time or across space. As predicted, richness changes were greatest when abundance and evenness changed in the same direction, and countervailing changes in abundance and evenness acted to constrain the magnitude of changes in species richness. Site‐to‐site differences in abundance, evenness, and richness were often decoupled, and pairwise relationships between these components across assemblages were weak. In contrast, changes in species richness and relative abundance were strongly correlated for assemblages varying through time. Temporal changes in local bio ersity showed greater inertia and stronger relationships between the component changes when compared to site‐to‐site variation. Overall, local variation in assemblage ersity was rarely due to repeated passive s les from an approximately static species abundance distribution. Instead, changing species relative abundances often dominated local variation in ersity. Moreover, how changing relative abundances combined with changes to total abundance frequently determined the magnitude of richness changes. Embracing the interdependencies between changing abundance, evenness and richness can provide new information to better understand bio ersity change in the Anthropocene.
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.
Publisher: Wiley
Date: 28-09-2010
DOI: 10.1111/J.1420-9101.2010.02105.X
Abstract: Polyandry has the potential to affect the distribution of phenotypes and to shape the direction of sexual selection. Here, we explore this potential using Trinidadian guppies as a model system and ask whether polyandry leads to directional and/or ersifying selection of male phenotypic traits. In this study, we compare the phenotypic ersity of offspring from multiply and singly sired broods. To quantify phenotypic ersity, we first combine phenotypic traits using multivariate methods, and then take the dispersion of in iduals in multivariate space as our measure of ersity. We show that, when each trait is examined separately, polyandry generates offspring with a higher proportion of bright coloration, indicating directional selection. However, our multivariate approach reveals that this directionality is accompanied by an increase in phenotypic ersity. These results suggest that polyandry (i) selects for the production of sons with the preferred brighter colour phenotypes whereas (ii) enhancing the ersity of male sexual traits. Promoting phenotypic ersity may be advantageous in coping with environmental and reproductive variability by increasing long-term fitness.
Publisher: Springer Science and Business Media LLC
Date: 04-09-2013
Abstract: Some of the most marked temporal fluctuations in species abundances are linked to seasons. In theory, multispecies assemblages can persist if species use shared resources at different times, thereby minimizing interspecific competition. However, there is scant empirical evidence supporting these predictions and, to the best of our knowledge, seasonal variation has never been explored in the context of fluctuation-mediated coexistence. Using an exceptionally well-documented estuarine fish assemblage, s led monthly for over 30 years, we show that temporal shifts in species abundances underpin species coexistence. Species fall into distinct seasonal groups, within which spatial resource use is more heterogeneous than would be expected by chance at those times when competition for food is most intense. We also detect seasonal variation in the richness and evenness of the community, again linked to shifts in resource availability. These results reveal that spatiotemporal shifts in community composition minimize competitive interactions and help stabilize total abundance.
Publisher: Springer Science and Business Media LLC
Date: 04-05-2020
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: The Royal Society
Date: 07-2020
DOI: 10.1098/RSOS.192045
Abstract: As pressures on bio ersity increase, a better understanding of how assemblages are responding is needed. Because rare species, defined here as those that have locally low abundances, make up a high proportion of assemblage species lists, understanding how the number of rare species within assemblages is changing will help elucidate patterns of recent bio ersity change. Here, we show that the number of rare species within assemblages is increasing, on average, across systems. This increase could arise in two ways: species already present in the assemblage decreasing in abundance but with no increase in extinctions, or additional species entering the assemblage in low numbers associated with an increase in immigration. The positive relationship between change in rarity and change in species richness provides evidence for the second explanation, i.e. higher net immigration than extinction among the rare species. These measurable changes in the structure of assemblages in the recent past underline the need to use multiple bio ersity metrics to understand bio ersity change.
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: Wiley
Date: 06-08-2007
DOI: 10.1111/J.1461-0248.2007.01094.X
Abstract: Species abundance distributions (SADs) follow one of ecology's oldest and most universal laws--every community shows a hollow curve or hyperbolic shape on a histogram with many rare species and just a few common species. Here, we review theoretical, empirical and statistical developments in the study of SADs. Several key points emerge. (i) Literally dozens of models have been proposed to explain the hollow curve. Unfortunately, very few models are ever rejected, primarily because few theories make any predictions beyond the hollow-curve SAD itself. (ii) Interesting work has been performed both empirically and theoretically, which goes beyond the hollow-curve prediction to provide a rich variety of information about how SADs behave. These include the study of SADs along environmental gradients and theories that integrate SADs with other bio ersity patterns. Central to this body of work is an effort to move beyond treating the SAD in isolation and to integrate the SAD into its ecological context to enable making many predictions. (iii) Moving forward will entail understanding how s ling and scale affect SADs and developing statistical tools for describing and comparing SADs. We are optimistic that SADs can provide significant insights into basic and applied ecological science.
Publisher: Wiley
Date: 22-08-2015
Publisher: Wiley
Date: 17-01-2011
Publisher: Springer Science and Business Media LLC
Date: 10-1999
DOI: 10.1038/44314
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: The Royal Society
Date: 07-01-2013
Abstract: Growing concern about bio ersity loss underscores the need to quantify and understand temporal change. Here, we review the opportunities presented by bio ersity time series, and address three related issues: (i) recognizing the characteristics of temporal data (ii) selecting appropriate statistical procedures for analysing temporal data and (iii) inferring and forecasting bio ersity change. With regard to the first issue, we draw attention to defining characteristics of bio ersity time series—lack of physical boundaries, uni-dimensionality, autocorrelation and directionality—that inform the choice of analytic methods. Second, we explore methods of quantifying change in bio ersity at different timescales, noting that autocorrelation can be viewed as a feature that sheds light on the underlying structure of temporal change. Finally, we address the transition from inferring to forecasting bio ersity change, highlighting potential pitfalls associated with phase-shifts and novel conditions.
Publisher: Wiley
Date: 28-04-2009
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Anne Magurran.