ORCID Profile
0000-0002-8589-8387
Current Organisation
The University of Edinburgh
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Publisher: Cold Spring Harbor Laboratory
Date: 29-03-2023
DOI: 10.1101/2023.03.28.534538
Abstract: Trait ersity, including trait turnover, that differentiates the roles of species and communities according to their functions, is a fundamental component of bio ersity. Accurately capturing trait ersity is crucial to better understand and predict community assembly, as well as the consequences of global change on community resilience. Existing methods to compute trait turnover have limitations. Trait space approaches based on minimum convex polygons only consider species with extreme trait values. Tree-based approaches using dendrograms consider all species but distort trait distance between species. More recent trait space methods using complex polytopes try to harmonise the advantages of both methods, but their current implementation have mathematical flaws. We propose a new kernel integral method (KIM) to compute trait turnover, based on the integration of kernel density estimators (KDEs) rather than using polytopes. We explore how this difference and the computational aspects of the KDE computation can influence the estimates of trait turnover. We compare our novel method to existing ones using justified theoretical expectations for a large number of simulations in which we control the number of species and the distribution of their traits. We illustrate the practical application of KIM using plant species introduced to the Pacific Islands of French Polynesia. Analyses on simulated data show that KIM generates results better aligned with theoretical expectations than other methods and is less sensitive to the total number of species. Analyses for French Polynesia data also show that different methods can lead to different conclusions about trait turnover, and that the choice of method should be carefully considered based on the research question. Mathematical aspects for computing trait turnover are crucial as they can have important effects on the results and therefore lead to different conclusions. Our novel kernel integral method generates values that better reflect the distribution of species in the trait space than other existing methods. We therefore recommend using KIM in future studies on trait turnover. In contrast, tree-based approaches should be kept for phylogenetic ersity, as phylogenetic trees will then reflect the constrained speciation process.
Publisher: Cold Spring Harbor Laboratory
Date: 09-11-2017
DOI: 10.1101/216580
Abstract: Zeta ersity provides the average number of shared species across n sites (or shared operational taxonomic units (OTUs) across n cases). It quantifies the variation in species composition of multiple assemblages in space and time to capture the contribution of the full suite of narrow, intermediate and wide-ranging species to biotic heterogeneity. Zeta ersity was proposed for measuring compositional turnover in plant and animal assemblages, but is equally relevant for application to any biological system that can be characterised by a row by column incidence matrix. Here we illustrate the application of zeta ersity to explore compositional change in empirical data, and how observed patterns may be interpreted. We use 10 datasets from a broad range of scales and levels of biological organisation – from DNA molecules to microbes, plants and birds – including one of the original data sets used by R.H. Whittaker in the 1960’s to express compositional change and distance decay using beta ersity. The applications show (i) how different s ling schemes used during the calculation of zeta ersity may be appropriate for different data types and ecological questions, (ii) how higher orders of zeta may in some cases better detect shifts, transitions or periodicity, and importantly (iii) the relative roles of rare versus common species in driving patterns of compositional change. By exploring the application of zeta ersity across this broad range of contexts, our goal is to demonstrate its value as a tool for understanding continuous bio ersity turnover and as a metric for filling the empirical gap that exists on spatial or temporal change in compositional ersity.
Publisher: Wiley
Date: 30-07-2020
DOI: 10.1111/COBI.13592
Publisher: Springer International Publishing
Date: 2020
Publisher: Wiley
Date: 04-2019
DOI: 10.1002/ECS2.2669
Publisher: Cold Spring Harbor Laboratory
Date: 19-10-2021
DOI: 10.1101/2021.10.18.464772
Abstract: The total impact of an alien species was conceptualised as the product of its range size, local abundance and per-unit effect in a seminal paper by Parker and colleagues in 1999, but a practical approach for estimating the three components has been lacking. Here, we generalise the impact formula and, through use of regression models, estimate the relationship between the three components of impact, an approach we term G-IRAE (Generalised Impact – Range size – Abundance – per-unit Effect). Moreover, we show that G-IRAE can also be applied to damage and management costs. We propose two methods for applying G-IRAE. The species-specific method computes the relationship for a given species across multiple invaded sites or regions, assuming a constant per-unit effect across the invaded area. The multi-species method combines data from multiple species across multiple sites or regions to calculate a per-unit effect for each species. While the species-specific method is more accurate, it requires a large amount of data for each species. The multi-species method is more easily applicable and data-parsimonious. We illustrate the multi-species method using data about money spent managing plant invasions in different biomes of South Africa. We found clear differences between species in terms of money spent per unit area invaded, with per-unit expenditures varying substantially between biomes for some species. G-IRAE offers a versatile and practical method which can be applied to many different types of data, to better understand and manage invasions.
Publisher: Springer Science and Business Media LLC
Date: 20-07-2022
DOI: 10.1007/S11625-022-01166-3
Abstract: The extent and impacts of biological invasions on bio ersity are largely shaped by an array of socio-economic and environmental factors, which exhibit high variation among countries. Yet, a global analysis of how these factors vary across countries is currently lacking. Here, we investigate how five broad, country-specific socio-economic and environmental indices (Governance, Trade, Environmental Performance, Lifestyle and Education, Innovation) explain country-level (1) established alien species (EAS) richness of eight taxonomic groups, and (2) proactive or reactive capacity to prevent and manage biological invasions and their impacts. These indices underpin many aspects of the invasion process, including the introduction, establishment, spread and management of alien species. They are also general enough to enable a global comparison across countries, and are therefore essential for defining future scenarios for biological invasions. Models including Trade, Governance, Lifestyle and Education, or a combination of these, best explained EAS richness across taxonomic groups and national proactive or reactive capacity. Historical (1996 or averaged over 1996–2015) levels of Governance and Trade better explained both EAS richness and the capacity of countries to manage invasions than more recent (2015) levels, revealing a historical legacy with important implications for the future of biological invasions. Using Governance and Trade to define a two-dimensional socio-economic space in which the position of a country captures its capacity to address issues of biological invasions, we identified four main clusters of countries in 2015. Most countries had an increase in Trade over the past 25 years, but trajectories were more geographically heterogeneous for Governance. Declines in levels of Governance are concerning as they may be responsible for larger levels of invasions in the future. By identifying the factors influencing EAS richness and the regions most susceptible to changes in these factors, our results provide novel insights to integrate biological invasions into scenarios of bio ersity change to better inform decision-making for policy and the management of biological invasions.
Publisher: Wiley
Date: 20-07-2017
DOI: 10.1111/DDI.12593
Publisher: Cold Spring Harbor Laboratory
Date: 06-02-2021
DOI: 10.1101/2021.02.04.429788
Abstract: The extent and impacts of biological invasions on bio ersity are largely shaped by an array of socio-ecological predictors, which exhibit high variation among countries. Yet a global synthetic perspective of how these factors vary across countries is currently lacking. Here, we investigate how a set of five socio-ecological predictors (Governance, Trade, Environmental Performance, Lifestyle and Education, Innovation) explain i) country-level established alien species (EAS) richness of eight taxonomic groups, and ii) country capacity to prevent and manage biological invasions and their impacts. Trade and Governance together best predicted the average EAS richness, increasing variance explained by up to 54% compared to models based on climatic and spatial variables only. Country-level EAS richness increased strongly with Trade, whereas high level of Governance resulted in lower EAS richness. Historical (1996) levels of Governance and Trade better explained response variables than current (2015) levels. Thus, our results reveal a historical legacy of these two predictors with profound implications for the future of biological invasions. We therefore used Governance and Trade to define a two-dimensional socio-economic space in which the position of a country captures its capacity to address issues of biological invasions. Our results provide novel insights into the complex relationship between socio-ecological predictors and biological invasions. Further, we highlight the need for designing better policies and management measures for alien species, and for integrating biological invasions in global environmental scenarios.
Publisher: Pensoft Publishers
Date: 15-10-2020
DOI: 10.3897/NEOBIOTA.62.53972
Abstract: The year 2020 and the next few years are critical for the development of the global bio ersity policy agenda until the mid-21 st century, with countries agreeing to a Post-2020 Global Bio ersity Framework under the Convention on Biological Diversity (CBD). Reducing the substantial and still rising impacts of invasive alien species (IAS) on bio ersity will be essential if we are to meet the 2050 Vision where bio ersity is valued, conserved, and restored. A tentative target has been developed by the IUCN Invasive Species Specialist Group (ISSG), and formally submitted to the CBD for consideration in the discussion on the Post-2020 targets. Here, we present properties of this proposal that we regard as essential for an effective Post-2020 Framework. The target should explicitly consider the three main components of biological invasions, i.e. (i) pathways, (ii) species, and (iii) sites the target should also be (iv) quantitative, (v) supplemented by a set of indicators that can be applied to track progress, and (vi) evaluated at medium- (2030) and long-term (2050) time horizons. We also present a proposed set of indicators to track progress. These properties and indicators are based on the increasing scientific understanding of biological invasions and effectiveness of responses. Achieving an ambitious action-oriented target so that the 2050 Vision can be achieved will require substantial effort and resources, and the cooperation of a wide range of stakeholders.
Publisher: Wiley
Date: 02-2021
DOI: 10.1002/ECS2.3359
Publisher: Cold Spring Harbor Laboratory
Date: 04-11-2021
DOI: 10.1101/2021.11.03.467033
Abstract: Community structure is determined by the interplay among different processes, including biotic interactions, abiotic filtering and dispersal. Their effects can be detected by comparing observed patterns of co-occurrence between different species (e.g. C-score and the natural metric) to patterns generated by null models based on permutations of species-by-site matrices under constraints on row or column sums. These comparisons enable us to detect significant signals of species association or dissociation, from which the type of biotic interactions between species (e.g. facilitative or antagonistic) can be inferred. Commonly used patterns are based on the levels of co-occurrence between randomly paired species. The level of co-occurrence for three or more species is rarely considered, ignoring the potential existence of functional guilds or motifs composed of multiple species within the community. Null model tests that do not consider multi-species co-occurrence could therefore generate false negatives (Type II error) in detecting non-random forces at play that would only be apparent for such guilds. Here, we propose a multi-species co-occurrence index (hereafter, joint occupancy) that measures the number of sites jointly occupied by multiple species simultaneously, of which the pairwise metric of co-occurrence is a special case. Using this joint occupancy index along with standard permutation algorithms for null model testing, we illustrate nine archetypes of multi-species co-occurrence and explore how frequent they are in the seminal database of 289 species-by-site community matrices published by Atmar and Patterson in 1995. We show that null model testing using pairwise co-occurrence metrics could indeed lead to severe Type II errors in one specific archetype, accounting for 2.4% of the tested community matrices.
Publisher: Cold Spring Harbor Laboratory
Date: 16-09-2022
DOI: 10.1101/2022.09.13.507777
Abstract: Invasive alien species are one of the major threats to global bio ersity, ecosystem integrity, nature’s contribution to people and human health. While scenarios about potential future developments have been available for other global change drivers for quite some time, we largely lack an understanding of how biological invasions might unfold in the future across spatial scales. Based on previous work on global invasion scenarios, we developed a workflow to downscale global scenarios to a regional and policy-relevant context. We applied this workflow at the European scale to create four European scenarios of biological invasions until 2050 that consider different environmental, socio-economic and socio-cultural trajectories, namely the European Alien Species Narratives (Eur-ASNs). We compared the Eur-ASNs with their previously published global counterparts (Global-ASNs), assessing changes in 26 scenario variables. This assessment showed a high consistency between global and European scenarios in the logic and assumptions of the scenario variables. However, several discrepancies in scenario variable trends were detected that could be attributed to scale differences. This suggests that the workflow is able to capture scale-dependent differences across scenarios. We also compared the Global- and Eur-ASNs with the widely used Global and European Shared Socioeconomic Pathways (SSPs), a set of scenarios developed in the context of climate change to capture different future socio-economic trends. Our comparison showed considerable ergences in the scenario space occupied by the different scenarios, with overall larger differences between the ASNs and SSPs than across scales (global vs. European) within the scenario initiatives. Given the differences between the ASNs and SSPs, it seems that the SSPs do not adequately capture the scenario space relevant to understanding the complex future of biological invasions. This underlines the importance of developing independent, but complementary, scenarios focused on biological invasions. The downscaling workflow we presented and implemented here provides a tool to develop such scenarios across different regions and contexts. This is a major step towards an improved understanding of all major drivers of global change including biological invasions.
Publisher: Springer Science and Business Media LLC
Date: 11-06-2022
DOI: 10.1007/S10530-022-02836-0
Abstract: The total impact of an alien species was conceptualised as the product of its range size, local abundance and per-unit effect in a seminal paper by Parker et al. (Biol Invasions 1:3–19, 1999). However, a practical approach for estimating the three components has been lacking. Here, we generalise the impact formula and, through use of regression models, estimate the relationship between the three components of impact, an approach we term GIRAE (Generalised Impact = Range size × Abundance × per-unit Effect). We discuss how GIRAE can be applied to multiple types of impact, including environmental impacts, damage and management costs. We propose two methods for applying GIRAE. The species-specific method computes the relationship between impact, range size, abundance and per-unit effect for a given species across multiple invaded sites or regions of different sizes. The multi-species method combines data from multiple species across multiple sites or regions to calculate a per-unit effect for each species and is computed using a single regression model. The species-specific method is more accurate, but it requires a large amount of data for each species and assumes a constant per-unit effect for a species across the invaded area. The multi-species method is more easily applicable and data-parsimonious, but assumes the same relationship between impact, range size and abundance for all considered species. We illustrate these methods using data about money spent managing plant invasions in different biomes of South Africa. We found clear differences between species in terms of money spent per unit area invaded, with per-unit expenditure varying substantially between biomes for some species—insights that are useful for monitoring and evaluating management. GIRAE offers a versatile and practical method that can be applied to many different types of data to better understand and manage the impacts of biological invasions.
Publisher: Wiley
Date: 09-06-2021
DOI: 10.1111/ECOG.05610
Abstract: The Amazon catchment is the largest river basin on earth, and up to 30% of its waters flow across floodplains. In its open waters, floating plants known as floating meadows abound. They can act as vectors of dispersal for their associated fauna and, therefore, can be important for the spatial structure of communities. Here, we focus on hibian ersity in the Amazonian floating meadows over large spatial scales. We recorded 50 hibian species over 57 sites, covering around 7000 km along river courses. Using multi‐site generalised dissimilarity modelling of zeta ersity, we tested Hanski's core‐satellite hypothesis and identified the existence of two functional groups of species operating under different ecological processes in the floating meadows. ‘Core' species are associated with floating meadows, while ‘satellite' species are associated with adjacent environments, being only occasional or accidental occupants of the floating vegetation. At large scales, hibian ersity in floating meadows is mostly determined by stochastic (i.e. random/neutral) processes, whereas at regional scales, climate and deterministic (i.e. niche‐based) processes are central drivers. Compared with the turnover of ‘core' species, the turnover of ‘satellite' species increases much faster with distances and is also controlled by a wider range of climatic features. Distance is not a limiting factor for ‘core' species, suggesting that they have a stronger dispersal ability even over large distances. This is probably related to the existence of passive long‐distance dispersal of in iduals along rivers via vegetation rafts. In this sense, Amazonian rivers can facilitate dispersal, and this effect should be stronger for species associated with riverine habitats such as floating meadows.
Publisher: Elsevier BV
Date: 08-2012
Publisher: Resilience Alliance, Inc.
Date: 2012
Publisher: Springer Science and Business Media LLC
Date: 29-08-2022
DOI: 10.1007/S10530-022-02858-8
Abstract: Community science (also often referred to as citizen science) provides a unique opportunity to address questions beyond the scope of other research methods whilst simultaneously engaging communities in the scientific process. This leads to broad educational benefits, empowers people, and can increase public awareness of societally relevant issues such as the bio ersity crisis. As such, community science has become a favourable framework for researching alien species where data on the presence, absence, abundance, phenology, and impact of species is important in informing management decisions. However, uncertainties arising at different stages can limit the interpretation of data and lead to projects failing to achieve their intended outcomes. Focusing on alien species centered community science projects, we identified key research questions and the relevant uncertainties that arise during the process of developing the study design, for ex le, when collecting the data and during the statistical analyses. Additionally, we assessed uncertainties from a linguistic perspective, and how the communication stages among project coordinators, participants and other stakeholders can alter the way in which information may be interpreted. We discuss existing methods for reducing uncertainty and suggest further solutions to improve data reliability. Further, we make suggestions to reduce the uncertainties that emerge at each project step and provide guidance and recommendations that can be readily applied in practice. Reducing uncertainties is essential and necessary to strengthen the scientific and community outcomes of community science, which is of particular importance to ensure the success of projects aimed at detecting novel alien species and monitoring their dynamics across space and time.
Publisher: Wiley
Date: 28-11-2022
Abstract: Ecological network structure is maintained by a generalist core of common species. However, rare species contribute substantially to both the species and functional ersity of networks. Capturing changes in species composition and interactions, measured as turnover, is central to understanding the contribution of rare and common species and their interactions. Due to a large contribution of rare interactions, the pairwise metrics used to quantify interaction turnover are, however, sensitive to compositional change in the interactions of, often rare, peripheral specialists rather than common generalists in the network. Here we expand on pairwise interaction turnover using a multi‐site metric that enables quantifying turnover in rare to common interactions (in terms of occurrence of interactions). The metric further separates this turnover into interaction turnover due to species turnover and interaction rewiring. We demonstrate the application and value of this method using a host–parasitoid system s led along gradients of environmental modification. In the study system, both the type and amount of habitat needed to maintain interaction composition depended on the properties of the interactions considered, that is, from rare to common. The analyses further revealed the potential of host switching to prevent or delay species loss, and thereby buffer the system from perturbation. Multi‐site interaction turnover provides a comprehensive measure of network change that can, for ex le, detect ecological thresholds to habitat loss for rare to common interactions. Accurate description of turnover in common, in addition to rare, species and their interactions is particularly relevant for understanding how network structure and function can be maintained.
Publisher: Wiley
Date: 16-07-2013
Abstract: Predators impact prey populations not only by consuming in iduals, but also by altering their behaviours. These nonlethal effects can influence food web properties as much as lethal effects. The mechanisms of nonlethal effects include chronic and temporary anti-predator behaviours, the nature of which depends on the spatial dynamics of predators and the range over which prey perceive risk. The relation between chronic and ephemeral responses to risk determines predator-prey interactions, with consequences that can ripple across the food web. Nonetheless, few studies have quantified the spatio-temporal scales over which prey respond to predation threat, and how this response varies with habitat features. We evaluated the reaction of radio-collared caribou and moose to the passage of radio-collared wolves, by considering changes in movement characteristics during winter and summer. We used an optimization algorithm to identify the rate at which the impact of prior passage of wolves decreases over time and with the predator's distance. The spatial and temporal scales of anti-predator responses varied with prey species and season. Caribou and moose displayed four types of behaviour following the passage of wolves: lack of response, increased selection of safe land cover types, decreased selection of risky cover types and increased selection of food-rich forest stands. For ex le, moose increased their avoidance of open conifer stands with lichen in summer, which are selected by wolves in this season. Also in winter, caribou increased their selection of conifer stands with lichen for nearly 10 days following a wolf's passage. This stronger selection for food-rich patches could indicate that the recent passage of wolves informs caribou on the current predator distribution and reveals the rate at which this information become less reliable over time. Caribou and moose used anti-predator responses that combine both long- and short-term behavioural adjustments. The spatial game between wolves and their prey involves complex and nonlinear mechanisms that vary between species and seasons. A comprehensive assessment of risk effects on ecosystem dynamics thus requires the characterization of chronic and temporary anti-predator behaviours.
Publisher: Springer Science and Business Media LLC
Date: 09-01-2020
Publisher: The Royal Society
Date: 05-2019
Abstract: Critical thermal limits (CTLs) show much variation associated with the experimental rate of temperature change used in their estimation. Understanding the full range of variation in rate effects on CTLs and their underlying basis is thus essential if methodological noise is not to overwhelm or bias the ecological signal. We consider the effects of rate variation from multiple intraspecific assessments and provide a comprehensive empirical analysis of the rate effects on both the critical thermal maximum (CT max ) and critical thermal minimum (CT min ) for 47 species of ectotherms, exploring which of the available theoretical models best explains this variation. We find substantial interspecific variation in rate effects, which takes four different forms (increase, decline, no change, mixed), with phylogenetic signal in effects on CT max , but not CT min . Exponential and zero exponential failure rate models best explain the rate effects on CT max . The majority of the empirical rate variation in CT min could not be explained by the failure rate models. Our work demonstrates that rate effects cannot be ignored in comparative analyses, and suggests that incorporation of the failure rate models into such analyses is a useful further avenue for exploration of the fundamental basis and implications of such variation.
Publisher: Wiley
Date: 14-08-2019
DOI: 10.1002/ECY.2832
Abstract: Incidence, or compositional, matrices are generated for a broad range of research applications in biology. Zeta ersity provides a common currency and conceptual framework that links incidence-based metrics with multiple patterns of interest in biology, ecology, and bio ersity science. It quantifies the variation in species (or OTU) composition of multiple assemblages (or cases) in space or time, to capture the contribution of the full suite of narrow, intermediate, and wide-ranging species to biotic heterogeneity. Here we provide a conceptual framework for the application and interpretation of patterns of continuous change in compositional ersity using zeta ersity. This includes consideration of the survey design context, and the multiple ways in which zeta ersity decline and decay can be used to examine and test turnover in the identity of elements across space and time. We introduce the zeta ratio-based retention rate curve to quantify rates of compositional change. We illustrate these applications using 11 empirical data sets from a broad range of taxa, scales, and levels of biological organization-from DNA molecules and microbes to communities and interaction networks-including one of the original data sets used to express compositional change and distance decay in ecology. We show (1) how different s le selection schemes used during the calculation of compositional change are appropriate for different data types and questions, (2) how higher orders of zeta may in some cases better detect shifts and transitions, and (3) the relative roles of rare vs. common species in driving patterns of compositional change. By exploring the application of zeta ersity decline and decay, including the retention rate, across this broad range of contexts, we demonstrate its application for understanding continuous turnover in biological systems.
Publisher: Wiley
Date: 23-05-2022
DOI: 10.1111/GEB.13530
Abstract: Spatial compositional turnover varies considerably among co‐occurring assemblages of organisms, presumably shaped by common processes related to species traits. We investigated patterns of spatial turnover in a erse set of marine assemblages using zeta ersity, which extends traditional pairwise measures of turnover to capture the roles of both rare and common species in shaping assemblage turnover. We tested the generality of hypothesized patterns related to ecological traits and provide insights into mechanisms of bio ersity change. Temperate pelagic and benthic marine assemblages of micro‐ and macroorganisms along south‐eastern Australia (30–36° S latitude). 2008–2021. Bacteria, phytoplankton, zooplankton, fish, and macrobenthic groups. Six marine datasets spanning bacteria to fishes were collated for measures of “species” occurrence, with a 1° latitude grain. For each assemblage, ecological traits of body size, habitat and trophic level were analysed for the form and rate of decline in zeta ersity and for the species retention rate. Species at higher trophic levels showed two to three times the rate of zeta ersity decline compared with lower trophic levels, indicating an increase in turnover from phytoplankton to carnivorous fishes. Body size showed the hypothesized unimodal relationship with rates of turnover for macroorganisms. Patterns of bacterial turnover contrasted with those found for macroorganisms, with the highest levels of turnover in pelagic habitats compared with benthic (kelp‐associated) habitats. The shape of retention rate curves showed the importance of both rare and common species in driving turnover a finding that would not have been observable using pairwise (beta ersity) measures of turnover. Our results support theoretical predictions for phytoplankton and macroorganisms, showing an increase in turnover rate with trophic level, but these predictions did not hold for bacteria. Such deviations from theory need to be investigated further to identify underlying processes that govern microbial assemblage dynamics.
Publisher: The Royal Society
Date: 22-12-2015
Abstract: Neutral and niche processes are generally considered to interact in natural communities along a continuum, exhibiting community patterns bounded by pure neutral and pure niche processes. The continuum concept uses niche separation, an attribute of the community, to test the hypothesis that communities are bounded by pure niche or pure neutral conditions. It does not accommodate interactions via feedback between processes and the environment. By contrast, we introduce the Community Assembly Phase Space (CAPS), a multi-dimensional space that uses community processes (such as dispersal and niche selection) to define the limiting neutral and niche conditions and to test the continuum hypothesis. We compare the outputs of modelled communities in a heterogeneous landscape, assembled by pure neutral, pure niche and composite processes. Differences in patterns under different combinations of processes in CAPS reveal hidden complexity in neutral–niche community dynamics. The neutral–niche continuum only holds for strong dispersal limitation and niche separation. For weaker dispersal limitation and niche separation, neutral and niche processes lify each other via feedback with the environment. This generates patterns that lie well beyond those predicted by a continuum. Inferences drawn from patterns about community assembly processes can therefore be misguided when based on the continuum perspective. CAPS also demonstrates the complementary information value of different patterns for inferring community processes and captures the complexity of community assembly. It provides a general tool for studying the processes structuring communities and can be applied to address a range of questions in community and metacommunity ecology.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2010
Publisher: Cold Spring Harbor Laboratory
Date: 06-06-2022
DOI: 10.1101/2022.06.06.494936
Abstract: Many plant traits covary with environmental gradients, reflecting shifts in adaptive strategies under changing conditions and thus providing information about potential consequences of future environmental change for vegetation and ecosystem functioning. Despite extensive efforts to map trait–environment relationships, the evidence remains heterogeneous and often conflicting, partially because of insufficient consideration of distinct trait syndromes for certain growth forms and habitats. Moreover, it is unclear whether traits of non-native and native plant taxa respond similarly to environmental gradients, limiting our ability to assess the consequences of future plant invasions. Here, using comprehensive data for Germany and the Czech Republic and a Bayesian multilevel modeling framework, we assessed relationships between three major plant traits (maximum height, H max specific leaf area, SLA and seed mass, SM ) and environmental factors (7 climate variables and percentage of urban land cover) for native and non-native woody and herbaceous plant assemblages across six broad habitat types. We projected the trait change in these assemblages under future environmental change scenarios until 2081–2100 and quantified the change in trait difference between native and non-native plants. Our models depicted multiple trait–environment relationships, with several important differences attributed to biogeographical status and woodiness within and across habitat types. The overall magnitude of trait change is projected to be greater for non-native than native taxa and to increase under more extreme scenarios. Native woody plant assemblages may generally experience an increase across all three traits, whereas woody non-natives may decline in H max and increase in SLA and SM . Herbaceous H max is expected to increase and SLA to decrease in most habitats. The obtained trait projections highlight the conditions under which non-native plants may prevail over natives and vice versa and can serve as a starting point for projecting future changes in ecosystem functions and services.
Publisher: Cold Spring Harbor Laboratory
Date: 06-09-2020
DOI: 10.1101/2020.09.04.282947
Abstract: Perspectives in conservation are based on a variety of value systems. Such differences in how people value nature and its components lead to different evaluations of the morality of conservation goals and approaches, and often underlie disagreements in the formulation and implementation of environmental management policies. Specifically, whether a conservation action (e.g. killing feral cats to reduce predation on bird species threatened with extinction) is viewed as appropriate or not can vary among people with different value systems. Here, we present a conceptual, mathematical framework intended as a tool to systematically explore and clarify core value statements in conservation approaches. Its purpose is to highlight how fundamental differences between these value systems can lead to different prioritizations of available management options and offer a common ground for discourse. The proposed equations decompose the question underlying many controversies around management decisions in conservation: what or who is valued, how, and to what extent? We compare how management decisions would likely be viewed under three different idealised value systems: ecocentric conservation, which aims to preserve bio ersity new conservation, which considers that bio ersity can only be preserved if it benefits humans and sentientist conservation, which aims at minimising suffering for sentient beings. We illustrate the utility of the framework by applying it to case studies involving invasive alien species, rewilding, and trophy hunting. By making value systems and their consequences in practice explicit, the framework facilitates debates on contested conservation issues, and complements philosophical discursive approaches about moral reasoning. We believe dissecting the core value statements on which conservation decisions are based will provide an additional tool to understand and address conservation conflicts.
Publisher: Elsevier BV
Date: 12-2021
Publisher: Wiley
Date: 08-08-2019
DOI: 10.1111/JBI.13671
Publisher: Cold Spring Harbor Laboratory
Date: 08-09-2022
DOI: 10.1101/2022.09.07.506838
Abstract: Future dynamics of biological invasions are highly uncertain because they depend on multiple environmental, societal and socio-economic drivers. We adopted a qualitative scenario approach to explore the future of invasive alien species (IAS) in Europe and created an overall strategy for their management that considers different plausible future developments. The scenarios and strategy were developed during two online workshops with a multidisciplinary team of experts. First, we downscaled four global scenarios of biological invasions to the European level. Second, we developed a management strategy structured into 19 goals that cover a broad array of IAS-related topics (i.e. policy, research, public awareness and biosecurity), and provided solutions for achieving these goals considering the European scenarios. Third, we identified four interrelated recommendations around which any long-term strategy for managing IAS in Europe can be structured: (i) a European biosecurity regime, (ii) a dedicated communication strategy, (iii) data standardization and management tools, and (iv) a monitoring and assessment system. Finally, we identified the feasibility of the IAS management strategy, finding strong differences among the four scenarios. High levels of technological development, public environmental awareness, and effectiveness of IAS policies facilitated the implementation of the overall management strategy. Together, our results indicate that it is time for a new management of biological invasions in Europe based on a more integrative perspective across sectors and countries to be better prepared for future challenges.
Publisher: Wiley
Date: 15-10-2015
DOI: 10.1111/JBI.12642
Publisher: Frontiers Media SA
Date: 04-09-2020
Publisher: Wiley
Date: 12-11-2018
DOI: 10.1002/ECY.2528
Abstract: Communities comprising alien species with different residence times are natural experiments allowing the assessment of drivers of community assembly over time. Stochastic processes (such as dispersal and fluctuating environments) should be the dominant factors structuring communities of exotic species with short residence times. In contrast, communities should become more similar, or systematically erge, if they contain exotics with increasing resident times, due to the increasing importance of deterministic processes (such as environmental filtering). We use zeta ersity (the number of species shared by multiple assemblages) to explore the relationship between the turnover of native species and two categories of alien species with different residence times (archaeophytes [introduced between 4000 BC and 1500 AD] and neophytes [introduced after 1500 AD]) in a network of nature reserves in central Europe. By considering multiple assemblages simultaneously, zeta ersity allows us to determine the contribution of rare and widespread species to turnover. Specifically, we explore the relative effects of assembly processes representing isolation by distance, environmental filtering, and environmental stochasticity (fluctuating environments) on zeta ersity using Multi-Site Generalized Dissimilarity Modelling (MS-GDM). Four clusters of results emerged. First, stochastic processes for structuring plant assemblages decreased in importance with increasing residence time. Environmental stochasticity only affected species composition for neophytes, offering possibilities to predict the spread debt of recent invasions. Second, native species turnover was well explained by environmental filtering and isolation by distance, although these factors did not explain the turnover of archaeophytes and neophytes. Third, native and alien species compositions were only correlated for rare species, whereas turnover in widespread alien species was surprisingly unrelated to the composition of widespread native species. Site-specific approaches would therefore be more appropriate for the monitoring and management of rare alien species, whereas species-specific approaches would suit widespread species. Finally, the size difference of nature reserves influences not only native species richness, but also their richness-independent turnover. A network of reserves must therefore be designed and managed using a variety of approaches to enhance native ersity, while controlling alien species with different residence times and degrees of commonness.
Publisher: Elsevier BV
Date: 05-2011
Publisher: Public Library of Science (PLoS)
Date: 30-06-2014
Publisher: Wiley
Date: 04-2017
Publisher: Springer Science and Business Media LLC
Date: 10-05-2021
DOI: 10.1007/S11625-021-00963-6
Abstract: Scenario analysis has emerged as a key tool to analyze complex and uncertain future socio-ecological developments. However, currently existing global scenarios (narratives of how the world may develop) have neglected biological invasions, a major threat to bio ersity and the economy. Here, we use a novel participatory process to develop a erse set of global biological invasion scenarios spanning a wide range of plausible global futures through to 2050. We adapted the widely used “two axes” scenario analysis approach to develop four families of four scenarios each, resulting in 16 scenarios that were later clustered into four contrasting sets of futures. Our analysis highlights that socioeconomic developments and technological innovation have the potential to shape biological invasions, in addition to well-known drivers, such as climate and human land use change and global trade. Our scenarios partially align with the shared socioeconomic pathways created by the climate change research community. Several factors that drive differences in biological invasions were underrepresented in the shared socioeconomic pathways in particular, the implementation of biosecurity policies. We argue that including factors related to public environmental awareness and technological and trade development in global scenarios and models is essential to adequately consider biological invasions in global environmental assessments and thereby obtain a more integrative picture of future social–ecological developments.
Publisher: Pensoft Publishers
Date: 15-10-2020
DOI: 10.3897/NEOBIOTA.62.52708
Abstract: The number of alien species introduced and undergoing range expansion in novel environments is steadily increasing, with important consequences for native ecosystems. The efficacy of management planning and decision making to limit such invasions can be improved by understanding how interventions will impact the population dynamics of recently introduced species. To do so, here we expand on a typological framework that enables the classification of populations over time into 10 categories of commonness, and apply it to a spatially discrete metapopulation with heterogeneous abundance across spatial units (patches). We use this framework to assess the effect of cross-boundary management on the capacity of a metapopulation with different demographic and dispersal characteristics, including time lags in population growth, to become common. We demonstrate this framework by simulating a simple theoretical metapopulation model capable of exploring a range of environments, species characteristics, and management actions. Management can vary in the efficacy of propagule interception between patches, and in the synchronisation of the implementation of these measures across patches (i.e. if management is implemented simultaneously across patches). Simulations show that poor interception efficacy that only modestly reduces the number of propagules entering a given spatial unit cannot be compensated for by strong management synchronisation between spatial units. Management synchronisation will nonetheless result in a reduction in rates of spread once a critical threshold of interception efficacy has been met. Finally, time lags in population growth that may result in delayed spread are an important aspect to be considered in management as they can lify the efficacy of management. Our results demonstrate how a typological framework of categories of commonness can be used to provide practical insights for the management of biological invasions.
Publisher: Springer Science and Business Media LLC
Date: 17-10-2022
DOI: 10.1038/S41559-022-01865-1
Abstract: The redistribution of alien species across the globe accelerated with the start of European colonialism. European powers were responsible for the deliberate and accidental transportation, introduction and establishment of alien species throughout their occupied territories and the metropolitan state. Here, we show that these activities left a lasting imprint on the global distribution of alien plants. Specifically, we investigated how four European empires (British, Spanish, Portuguese and Dutch) structured current alien floras worldwide. We found that compositional similarity is higher than expected among regions that once were occupied by the same empire. Further, we provide strong evidence that floristic similarity between regions occupied by the same empire increases with the time a region was occupied. Network analysis suggests that historically more economically or strategically important regions have more similar alien floras across regions occupied by an empire. Overall, we find that European colonial history is still detectable in alien floras worldwide.
Publisher: Cold Spring Harbor Laboratory
Date: 17-05-2018
DOI: 10.1101/324897
Abstract: Spatial variation in compositional ersity, or species turnover, is necessary for capturing the components of heterogeneity that constitute bio ersity. However, no incidence-based metric of pairwise species turnover can calculate all components of ersity partitioning. Zeta (ζ) ersity, the mean number of species shared by any given number of sites or assemblages, captures all ersity components produced by assemblage partitioning. zeta is an R package for analysing and measuring compositional change for occurrence data using zeta ersity. Four types of analyses are performed on bird composition data in Australia: (i) decline in zeta ersity (ii) distance decay (iii) multi-site generalised dissimilarity modelling and (iv) hierarchical scaling. Some analyses, such as the zeta decline, are specific to zeta ersity, whereas others, such as distance decay, are commonly applied to beta ersity, and have been adapted using zeta ersity to differentiate the contribution of common and rare species to compositional change. An R package to analyse compositional change using zeta ersity is presented. Zeta ersity is the mean number of species shared by any number of assemblages Zeta ersity captures all ersity components produced by assemblage partitioning Analyses relate zeta ersity to space, environment and spatial scale Analyses differentiate the contribution of rare and common species to bio ersity
Publisher: IEEE
Date: 04-2007
Publisher: Elsevier BV
Date: 05-2017
Publisher: Pensoft Publishers
Date: 23-03-2022
DOI: 10.3897/NEOBIOTA.72.79070
Abstract: Perspectives in conservation are based on a variety of value systems. Such differences in how people value nature and its components lead to different evaluations of the morality of conservation goals and approaches, and often underlie disagreements in the formulation and implementation of environmental management policies. Specifically, whether a conservation action (e.g. killing feral cats to reduce predation on bird species threatened with extinction) is viewed as appropriate or not can vary among people with different value systems. Here, we present a conceptual, mathematical framework intended as a tool to systematically explore and clarify core value statements in conservation approaches. Its purpose is to highlight how fundamental differences between these value systems can lead to different prioritizations of available management options and offer a common ground for discourse. The proposed equations decompose the question underlying many controversies around management decisions in conservation: what or who is valued, how, and to what extent? We compare how management decisions would likely be viewed under three idealised value systems: ecocentric conservation, which aims to preserve bio ersity new conservation, which considers that bio ersity can only be preserved if it benefits humans and sentientist conservation, which aims at minimising suffering for sentient beings. We illustrate the utility of the framework by applying it to case studies involving invasive alien species, rewilding, and trophy hunting. By making value systems and their consequences in practice explicit, the framework facilitates debates on contested conservation issues, and complements philosophical discursive approaches about moral reasoning. We believe dissecting the core value statements on which conservation decisions are based will provide an additional tool to understand and address conservation conflicts.
Publisher: Copernicus GmbH
Date: 03-07-2018
Abstract: Abstract. The extent to which climate conditions influenced the spatial distribution of hominin populations in the past is highly debated. General circulation models (GCMs) and archaeological data have been used to address this issue. Most GCMs are not currently capable of simulating past surface climate conditions with sufficiently detailed spatial resolution to distinguish areas of potential hominin habitat, however. In this paper, we propose a statistical downscaling method (SDM) for increasing the resolution of climate model outputs in a computationally efficient way. Our method uses a generalised additive model (GAM), calibrated over present-day climatology data, to statistically downscale temperature and precipitation time series from the outputs of a GCM simulating the climate of the Last Glacial Maximum (19 000–23 000 BP) over western Europe. Once the SDM is calibrated, we first interpolate the coarse-scale GCM outputs to the final resolution and then use the GAM to compute surface air temperature and precipitation levels using these interpolated GCM outputs and fine-resolution geographical variables such as topography and distance from an ocean. The GAM acts as a transfer function, capturing non-linear relationships between variables at different spatial scales and correcting for the GCM biases. We tested three different techniques for the first interpolation of GCM output: bilinear, bicubic and kriging. The resulting SDMs were evaluated by comparing downscaled temperature and precipitation at local sites with paleoclimate reconstructions based on paleoclimate archives (archaeozoological and palynological data) and the impact of the interpolation technique on patterns of variability was explored. The SDM based on kriging interpolation, providing the best accuracy, was then validated on present-day data outside of the calibration period. Our results show that the downscaled temperature and precipitation values are in good agreement with paleoclimate reconstructions at local sites, and that our method for producing fine-grained paleoclimate simulations is therefore suitable for conducting paleo-anthropological research. It is nonetheless important to calibrate the GAM on a range of data encompassing the data to be downscaled. Otherwise, the SDM is likely to overcorrect the coarse-grain data. In addition, the bilinear and bicubic interpolation techniques were shown to distort either the temporal variability or the values of the response variables, while the kriging method offered the best compromise. Since climate variability is an aspect of the environment to which human populations may have responded in the past, the choice of interpolation technique is therefore an important consideration.
Publisher: Elsevier BV
Date: 09-2017
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Guillaume Latombe.