17 research outputs found

    Do large-scale associations in birds imply biotic interactions or environmental filtering?

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    Aim There has been a wide interest in the effect of biotic interactions on species' occurrences and abundances at large spatial scales, coupled with a vast development of the statistical methods to study them. Still, evidence for whether the effects of within-trophic-level biotic interactions (e.g. competition and heterospecific attraction) are discernible beyond local scales remains inconsistent. Here, we present a novel hypothesis-testing framework based on joint dynamic species distribution models and functional trait similarity to dissect between environmental filtering and biotic interactions. Location France and Finland. Taxon Birds. Methods We estimated species-to-species associations within a trophic level, independent of the main environmental variables (mean temperature and total precipitation) for common species at large spatial scale with joint dynamic species distribution (a multivariate spatiotemporal delta model) models. We created hypotheses based on species' functionality (morphological and/or diet dissimilarity) and habitat preferences about the sign and strength of the pairwise spatiotemporal associations to estimate the extent to which they result from biotic interactions (competition, heterospecific attraction) and/or environmental filtering. Results Spatiotemporal associations were mostly positive (80%), followed by random (15%), and only 5% were negative. Where detected, negative spatiotemporal associations in different communities were due to a few species. The relationship between spatiotemporal association and functional dissimilarity among species was negative, which fulfils the predictions of both environmental filtering and heterospecific attraction. Main conclusions We showed that processes leading to species aggregation (mixture between environmental filtering and heterospecific attraction) seem to dominate assembly rules, and we did not find evidence for competition. Altogether, our hypothesis-testing framework based on joint dynamic species distribution models and functional trait similarity is beneficial in ecological interpretation of species-to-species associations from data covering several decades and biogeographical regions.Peer reviewe

    Planetary well-being

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    Tensions between the well-being of present humans, future humans, and nonhuman nature manifest in social protests and political and academic debates over the future of Earth. The increasing consumption of natural resources no longer increases, let alone equalises, human well-being, but has led to the current ecological crisis and harms both human and nonhuman well-being. While the crisis has been acknowledged, the existing conceptual frameworks are in some respects ill-equipped to address the crisis in a way that would link the resolving of the crisis with the pivotal aim of promoting equal well-being. The shortcomings of the existing concepts in this respect relate to anthropocentric normative orientation, methodological individualism that disregards process dynamics and precludes integrating the considerations of human and nonhuman well-being, and the lack of multiscalar considerations of well-being. This work derives and proposes the concept of planetary well-being to address the aforementioned conceptual issues, to recognise the moral considerability of both human and nonhuman well-being, and to promote transdisciplinary, cross-cultural discourse for addressing the crisis and for promoting societal and cultural transformation. Conceptually, planetary well-being shifts focus on well-being from individuals to processes, Earth system and ecosystem processes, that underlie all well-being. Planetary well-being is a state where the integrity of Earth system and ecosystem processes remains unimpaired to a degree that species and populations can persist to the future and organisms have the opportunity to achieve well-being. After grounding and introducing planetary well-being, this work shortly discusses how the concept can be operationalised and reflects upon its potential as a bridging concept between different worldviews.</p

    Species co-occurrence networks of ground beetles in managed grasslands

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    Grassland biodiversity, including traditional rural biotopes maintained by traditional agricultural practices, has become threatened worldwide. Road verges have been suggested to be complementary or compensatory habitats for species inhabiting grasslands. Species co-occurrence patterns linked with species traits can be used to separate between the different mechanisms (stochasticity, environmental filtering, biotic interactions) behind community structure. Here, we study species co-occurrence networks and underlying mechanisms of ground beetle species (Carabidae) in three different managed grassland types (meadows, pastures, road verges, n = 12 in each type) in Central Finland. We aimed to find out whether road verges can be considered as compensatory to traditional rural biotopes (meadows and pastures). We found that stochasticity explained over 90% of the pairwise co-occurrences, and the non-random co-occurrences were best explained by environmental filtering, regardless of the grassland type. However, the identities and traits of the species showing non-random co-occurrences differed among the habitat types. Thus, environmental factors behind environmental filtering differ among the habitat types and are related to the site-specific characteristics and variation therein. This poses challenges to habitat management since the species’ response to management action may depend on the site-specific characteristics. Although road verges are not fully compensatory to meadows and pastures, the high similarity of species richness and the high level of shared species suggest that for carabids road verges may be corridors connecting the sparse network of the remaining traditional rural biotopes.peerReviewe

    Linking species interactions with phylogenetic and functional distance in European bird assemblages at broad spatial scales

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    Aim: Understanding the relative contribution of different species interactions in shaping community assembly has been a pivotal aim in community ecology. Biotic interactions are acknowledged to be important at local scales, although their signal is assumed to weaken over longer distances. We examine the relationship between positive, neutral and negative pairwise bird abundance distributions and the phylogenetic and functional distance between these pairs after first controlling for habitat associations. Location: France and Finland. Time period: 1984 to 2011 (Finland), 2001 to 2012 (France). Major Taxa studied: Birds. Methods: We used results from French and Finnish land bird monitoring programmes, from which we created three independent datasets (French forests, French farmlands and Finnish forests). Separately for the three datasets, we fitted linear mixed-effects models for pairwise abundance values across years per point count station to infer the association between all common species pairs, while controlling for geographical distribution and habitat associations, and saved pairwise regression coefficients for further analyses. We used a null model approach to infer whether the observed associations (effect sizes) differ from random. Finally, using quantile regression, we analysed the relationships between functional dissimilarity/phylogenetic distance and effect sizes. Results: Our results show both negative and positive species interactions, although negative interactions were twice as common as positive interactions. Closely related species were more likely to show strong associations, both negative and positive, than more distant species across broad spatial scales. For functional dissimilarity, the results varied across datasets. Main conclusions: Our results emphasize the potential of functional and phylogenetic proximity in generating both negative and positive species associations, which can produce pervasive patterns from local to geographical scales. Future assembly studies should refrain from strict dichotomies, such as compensatory dynamics versus environmental forcing, and instead consider the possibility of positive interactions.peerReviewe

    The mechanistic basis of changes in community assembly in relation to anthropogenic disturbance and productivity

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    In the human-dominated world the natural drivers of species diversity, such as productivity and habitat heterogeneity, have been accompanied by anthropogenic disturbance resulting in increased extinction rates at global scale. However, decrease in species richness does not necessarily result in local decreases in species richness. Moreover, species richness provides limited information on processes that cause changes within and between communities, and the mechanistic basis of these changes remains elusive. As all patterns in community ecology can be understood as a result of four processes (speciation, selection, drift, and dispersal), the effect of disturbance should depend on how disturbance disrupt these processes. We studied the effects of disturbance and productivity on species richness, community composition, and beta diversity (i.e. spatial variation in community composition) in the vegetation of 120 boreal peatlands. Using null model approach we determined whether community assembly processes differ between pristine and disturbed sites. Sites represented three peatland ecosystem types, each with two levels of productivity. Half of the sites were pristine and half were drained for forestry, which causes a major ecosystem level disturbance. Our results showed that high productivity sites encompassed higher species richness and different communities than low productivity sites. By contrast, we did not observe any difference in beta diversity between high and low productivity sites. Between pristine and drained sites neither species richness and nor beta diversity differed. Instead, peatland communities in drained were dissimilar to pristine sites, thus showing changes not attributed to drift but to selection, most likely based on altered hydrology, pH, and nutrient gradients. Moreover, the changes due to drainage were toward forest communities which could lead to landscape level homogenization. Effective ways to combine knowledge of the landscape level changes among disturbed areas and the understanding of the mechanisms affecting communities locally are important for reaching the ambitious global targets of restoring the degraded ecosystems. 1. Elo et al. (2016) The mechanistic basis of changes in community assembly in relation to anthropogenic disturbance and productivity. Ecosphere 7: e01310peerReviewe

    The effect of buffer strip width and selective logging on streamside polypore communities

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    Preserving streamside forest habitats or buffer strips is considered to reduce forestry-related biodiversity loss in commercial forest landscapes. However, it is still unclear what type of management in and near streamside forests can be undertaken without compromising their biodiversity and natural change through succession. Using a before–after, control–impact study design, we tested the impacts of forested buffer strips (15 or 30 m wide, with or without selective logging), preserved after clear-cutting, on the changes of polypore communities in streamside boreal forests in Finland. Manipulations in 28 sites produced four treatment classes, the community compositions of which were compared with seven unmanaged controls before and 12 years after the manipulations. The polypore community composition in 15 m wide buffer strips changed differently than that in controls and resembled the community composition typically found in production forests. Moreover, selective logging tended to homogenize polypore communities. These responses of polypore communities indicate that the natural biodiversity and succession of streamside forests was disturbed in both 15 m wide and selectively logged buffer strips. Streamside forests in nonlogged 30 m wide buffer strips seemed to retain the natural polypore community composition and succession, at least during the 12-year period.peerReviewe