14 research outputs found

    Improving spatial predictions of taxonomic, functional and phylogenetic diversity

    Get PDF
    In this study, we compare two community modelling approaches to determine their ability to predict the taxonomic, functional and phylogenetic properties of plant assemblages along a broad elevation gradient and at a fine resolution. The first method is the standard stacking individual species distribution modelling (SSDM) approach, which applies a simple environmental filter to predict species assemblages. The second method couples the SSDM and macroecological modelling (MEMSSDM-MEM) approaches to impose a limit on the number of species co-occurring at each site. Because the detection of diversity patterns can be influenced by different levels of phylogenetic or functional trees, we also examine whether performing our analyses from broad to more exact structures in the trees influences the performance of the two modelling approaches when calculating diversity indices. We found that coupling the SSDM with the MEM improves the overall predictions for the three diversity facets compared with those of the SSDM alone. The accuracy of the SSDM predictions for the diversity indices varied greatly along the elevation gradient, and when considering broad to more exact structure in the functional and phylogenetic trees, the SSDM-MEM predictions were more stable. SSDM-MEM moderately but significantly improved the prediction of taxonomic diversity, which was mainly driven by the corrected number of predicted species. The performance of both modelling frameworks increased when predicting the functional and phylogenetic diversity indices. In particular, fair predictions of the taxonomic composition by SSDM-MEM led to increasingly accurate predictions of the functional and phylogenetic indices, suggesting that the compositional errors were associated with species that were functionally or phylogenetically close to the correct ones; however, this did not always hold for the SSDM predictions.Synthesis. In this study, we tested the use of a recently published approach that couples species distribution and macroecological models to provide the first predictions of the distribution of multiple facets of plant diversity: taxonomic, functional and phylogenetic. Moderate but significant improvements were obtained; thus, our results open promising avenues for improving our ability to predict the different facets of biodiversity in space and time across broad environmental gradients when functional and phylogenetic information is available

    The role of phylogeny in the spatial distributions and assembly of mountain plant communities.

    No full text
    A major challenge in community ecology is a thorough understanding of the processes that govern the assembly and composition of communities in time and space. The growing threat of climate change to the vascular plant biodiversity of fragile ecosystems such as mountains has made it equally imperative to develop comprehensive methodologies to provide insights into how communities are assembled. In this perspective, the primary objective of this PhD thesis is to contribute to the theoretical and methodological development of community ecology, by proposing new solutions to better detect the ecological and evolutionary processes that govern community assembly. As phylogenetic trees provide by far, the most advanced tools to integrate the spatial, ecological and evolutionary dynamics of plant communities, they represent the cornerstone on which this work was based. In this thesis, I proposed new solutions to: (i) reveal trends in community assembly on phylogenies, depicted by the transition of signals at the nodes of the different species and lineages responsible for community assembly, (ii) contribute to evidence the importance of evolutionarily labile traits in the distribution of mountain plant species. More precisely, I demonstrated that phylogenetic and functional compositional turnover in plant communities was driven by climate and human land use gradients mostly influenced by evolutionarily labile traits, (iii) predict and spatially project the phylogenetic structure of communities using species distribution models, to identify the potential distribution of phylogenetic diversity, as well as areas of high evolutionary potential along elevation. The altitudinal setting of the Diablerets mountains (Switzerland) provided an appropriate model for this study. The elevation gradient served as a compression of large latitudinal variations similar to a collection of islands within a single area, and allowed investigations on a large number of plant communities. Overall, this thesis highlights that stochastic and deterministic environmental filtering processes mainly influence the phylogenetic structure of plant communities in mountainous areas. Negative density-dependent processes implied through patterns of phylogenetic overdispersion were only detected at the local scale, whereas environmental filtering implied through phylogenetic clustering was observed at both the regional and local scale. Finally, the integration of indices of phylogenetic community ecology with species distribution models revealed the prospects of providing novel and insightful explanations on the potential distribution of phylogenetic biodiversity in high mountain areas. These results generally demonstrate the usefulness of phylogenies in inferring assembly processes, and are worth considering in the theoretical and methodological development of tools to better understand phylogenetic community structure

    The nature fit concept of waste reduction: Prospects for engineering a clean future

    No full text
    Environmental pollution due to waste substances is an urgent problem around the world. As human population and the consumption of manufactured goods continue to increase, it is inevitable that large quantities of waste substances would simultaneously persist indiscriminately in aquatic and terrestrial environments, if natural solutions are not urgently sought. Worse still, an estimated two billion tonnes of wastes generated by humans annually constitute a huge burden on earth’s ecosystem health and the taxpayers beleaguered with the maintenance of clean environments. Given this challenge, the purpose of this review is to introduce the “nature fit” concept of waste reduction (NFWR) to develop new unified waste estimation methods along principal waste generation cardinals of the waste chain, termed “EPCD”. This novel approach galvanizes for the inculcation of nature-based solutions and green innovations adapted to the NFWR-EPCD cardinal system estimations of waste generation into existing waste management practices. This is necessary to salvage human and environmental health, and ensure better waste governance across the world

    Understanding the concepts of community phylogenetics

    No full text
    Background: Community phylogenetics is an emerging field of research that has made important contributions to understanding community assembly. The rapid development of this field can be attributed to the merging of phylogenetics and community ecology research to provide improved clarity on the processes that govern community structure and composition. Question: What are the major challenges that impede the sound interpretation of the patterns and processes of phylogenetic community assembly? Methods: We use four scenarios to illustrate explicitly how the phylogenetic structure of communities can exist in stable or transient phases, based on the different combinations of phylogenetic relationships and phenotypic traits among co-occurring species. We discuss these phases by implicating a two-way process in the assembly and disintegration of the given ecological community. Conclusions: This paper synthesizes the major concepts of community phylogenetics using habitat filtering and competition processes to elucidate how the understanding of phylogenetic community structure is currently hindered by the dynamics of community assembly and disassembly

    Soil seed bank dynamics in Tithonia diversifolia dominated fallowland at Ile- Ife, South-western Nigeria

    Get PDF
    The soil seed bank of Tithonia diversifolia, an invasive species which dominates open waste fallowland vegetation was studied. Two different roadside sites which vary in extent of open waste land were selected. The species composition of the established vegetation was assessed in the two different sites. Twenty top soil samples were collected at 0-15 cm five different distances (15 m, 30 m, 45 m, 60 m, and 75 m) inwards away from each main road in dry and rainy seasons and the seed bank composition was determined by greenhouse germination over a 6 month period. The similarity between the composition of the seed bank flora and that of the established vegetation was low. The least and the highest emerged seedlings density were recorded in the 15 m and 75 m respectively inwards away from the main road in both seasons. The results of the seedlings emergence are a reflection of the extent of open waste land dominated by the invasive species due to human disturbance (road construction) on both sites. Overall results suggest that the emergence of the species from the soil seed bank may be due to the impact of the invasive species – Tithonia diversifolia on other plant species in the study environment.© 2009 International Formulae Group. All rights reserved.Keywords: Fallowland, invasive species, seedling emergence, seed bank
    corecore