Biology subjects

Bonte, D.

Publications and source records attributed to Bonte, D..

9 recordsLinked to original sources

bioRxiv2018

Interspecific plant competition mediates impact of climate change on the ecophysiology of a plant-herbivore interaction.

O_LIBiotic interactions shape community evolution, but we lack mechanistic insights on how metabolic and ecological processes under climate change are altered by biotic interactions.\nC_LIO_LIWe used a two-trophic model community consisting of the aphid Dysaphis plantaginea feeding on the forb Plantago lanceolata, and a grass competitor Lolium perenne that does not experience herbivory by the aphid. Monocultures and mixtures were exposed to the herbivory treatment and to three relevant simulated environmental changes as prevalent under current climate change (increased temperature, CO2, and increased temperature and CO2)\nC_LIO_LIElevated CO2 reduced the nitrogen content of P. lanceolata, while simultaneous increases of CO2 and temperature modified the plant metabolic component and the magnitude of these responses in different directions. Elevated CO2 enhanced defence systems in P. lanceolata, but these effects were not altered by warming. Interspecific plant competition did, however, neutralise these responses. There were no indirect effects of climate change on aphid population growth despite changes in plant defense, nutritional quality and biomass induced by our environmental change scenarios.\nC_LIO_LIWe thus demonstrate interactions between abiotic and biotic processes on plant metabolite profiles, but more importantly, that climate change effect on a selection of the metabolic pathways are altered by herbivory and competition. Our experiment under semi-natural conditions thus demonstrates the non-additive and often neutralizing effects of biotic interactions on plant metabolism and species performance under climate-associated environmental change.\nC_LI

ecology↗

bioRxiv2018

Habitat choice stabilizes metapopulation dynamics through increased ecological specialisation.

Dispersal is a key trait responsible for the spread of individuals and genes among local populations, thereby generating eco-evolutionary interactions. Especially in heterogeneous metapopulations, a tight coupling between dispersal, population dynamics and the evolution of local adaptation is expected. In this respect, current theory predicts dispersal to counteract ecological specialisation by redistributing locally selected phenotypes (i.e. migration load). However, in nature we observe that some specialists exhibit a strong dispersal capacity.\n\nHabitat choice following informed dispersal decisions, provides a possible mechanism for individuals to match the environment to their phenotype, thereby enabling the persistence of evolved ecological specialisation. How such informed decisions affect the evolution of dispersal and ecological specialisation and how these, in turn, influence metapopulation dynamics is yet to be determined.\n\nBy means of individual-based modelling, we show that informed decisions on both departure and settlement decouples the evolution of dispersal and generalism, favouring highly dispersive specialists. Choice at settlement decouples dispersal from ecological specialisation most effectively. Additionally, habitat choice stabilizes local and metapopulation demography because of the maintenance of ecological specialisation at all levels of dispersal propensity.\n\nWe advocate considering habitat choice in spatially structured ecological models to improve demographic predictions in the face of environmental change.

evolutionary biology↗

bioRxiv2018

Size-dependent movement explains why bigger is better in fragmented landscapes

Body size is a fundamental trait known to allometrically scale with metabolic rate, and therefore a key determinant of individual development, life history and consequently fitness. In spatially structured environments, movement is an equally important driver of fitness. Because movement is tightly coupled with body size, we expect habitat fragmentation to induce a strong selection pressure on size variation across and within species. Changes in body size distributions are then, in turn, expected to alter food web dynamics. However, no consensus has been reached on how spatial isolation and resource growth affect body size distributions.\n\nOur aim was to investigate how these two factors shape the body size distribution of consumers under scenarios of size-dependent and -independent consumer movement by applying a mechanistic, individual-based resource-consumer model. The outcome was then linked to important ecosystem traits such as resource abundance and stability. Finally, we determined those factors that explain most variation in size distributions.\n\nWe demonstrate that decreasing connectivity and resource growth select for communities (or populations) consisting of larger species (or individuals) due to strong selection for the ability to move over longer distances. When including size-dependent movement, moderate levels of connectivity result in increases in local size diversity. Due to this elevated functional diversity, resource uptake is optimized at the metapopulation or metacommunity level. At these intermediate levels of connectivity, size-dependent movement explains most of the observed variation in size distributions. Interestingly, local and spatial stability of consumer biomass are lowest when isolation and resource productivity are high. Finally, we highlight that size-dependent movement is of vital importance for the survival of populations within highly fragmented landscapes. Our results demonstrate that considering size-dependent movement and resource growth is essential to understand patterns of size distributions at the population or community level and the resulting metapopulation or metacommunity dynamics.

ecology↗

bioRxiv2018

Information use during movement regulates how fragmentation and loss of habitat affect body size.

An individual's body size is central to its behavior and physiology, and tightly linked to its dispersal ability. The spatial arrangement of resources and a consumer's capacity to locate them are therefore expected to exert strong selection on consumer body size.\n\nWe investigated the evolutionary impact of both the fragmentation and loss of habitat on consumer body size and its feedback effects on resource distribution, under varying levels of information use during the settlement phase of dispersal. We developed a mechanistic, individual-based, spatially explicit model, including several allometric rules for key consumer traits. Our model reveals that as resources become more fragmented and scarce, informed settlement selects for larger body sizes while random settlement promotes small sizes. Information use may thus be an overlooked explanation for the observed variation in body size responses to habitat fragmentation. Moreover, we find that resources can accumulate and aggregate if information on resource abundance is incomplete. Informed movement results in stable resource-consumer dynamics and controlled resources across space. However, habitat fragmentation and loss destabilize local dynamics and disturb resource suppression by the consumer. Considering information use during movement is thus critical to understand the eco-evolutionary dynamics underlying the functioning and structuring of consumer communities.

ecology↗

bioRxiv2017

A simple spatially explicit neutral model explains range size distribution of reef fishes

AimThe great variation in range sizes among species has fascinated ecologists for decades. In reef-associated fish species, which live in fragmented habitats and adopt a wide range of dispersal strategies, we may expect species with greater dispersal ability to spread over larger ranges. However, empirical evidence for such a positive relationship between dispersal and range size in reef fishes remains scarce. Here, we unveil the more nuanced role of dispersal on the range size distribution of reef associated fishes using empirical data and a novel spatially explicit model.\n\nLocationTropical Eastern Pacific\n\nMajor taxa studiedReef-associated fishes\n\nMethodsWe estimated range size distributions for six different guilds of all reef-associated fishes with different dispersal abilities. We used a one-dimensional spatially explicit neutral model, which simulates the distribution of species along a linear coastline to explored the effect of dispersal, speciation and sampling on the distribution of range sizes. Our model adopts a more realistic gradual speciation process (protracted speciation) and incorporates important long distance dispersal events with a fat-tail dispersal kernel. We simulated our model using a highly efficient coalescence approach, which guarantees the metacommunity, is sampled at dynamic equilibrium. We fitted the model to the empirical data using an approximate Bayesian computation approach, with a sequential Monte Carlo algorithm.\n\nResultsStochastic birth, death, speciation and dispersal events alone can accurately explain empirical range size distributions for six different guilds of tropical, reef-associated fishes. Variation in range size distributions among guilds are explained purely by differences in dispersal ability with the best dispersers covering larger ranges.\n\nMain conclusionsA simple combination of neutral processes with guild-specific dispersal ability provides a general explanation for both within- and across-guild range size variation. Our results support the theoretically expected, but empirically much debated, hypothesis that dispersal promotes range size.

ecology↗

bioRxiv2017

Cobwebbing in the city: urbanization-driven shifts in body-size dependent behaviours are decoupled from body size in an orb-web spider

O_LIIn animals, behavioural responses may play an important role in determining population persistence in the face of environmental changes. Body size is a key trait central to many life history traits and behaviours. While behaviours are typically assumed to be highly plastic, size correlations may impose constraints on their adaptive value when size itself is subject to environmental changes.\nC_LIO_LIUrbanization is an important human-induced rapid environmental change that imposes multiple selection pressures on both body size and (size-constrained) behaviour. How these combine to shape behavioural responses of urban-dwelling species is unclear.\nC_LIO_LIUsing web-building, an easily quantifiable behaviour linked to body size, and the garden spider Araneus diadematus as a model, we disentangle direct behavioural responses to urbanization and body size constraints across a network of 63 selected populations differing in urbanization intensity at two spatial scales.\nC_LIO_LISpiders were smaller in highly urbanized sites (local scale only), in line with expectations based on reduced prey biomass availability and the Urban Heat Island effect. The use of multivariate mixed modelling reveals that although web traits and body size are correlated within populations, behavioural responses to urbanization do not appear to be constrained by size: there is no evidence of size-web correlations among populations or among landscapes. Spiders thus altered different components of their web-building behaviours independently in response to urbanization: mesh width and web surface decreased independently with urbanization at the local scale, while web surface also increased with urbanization at the landscape scale. These responses are expected to compensate, at least in part, for reduced prey biomass availability.\nC_LIO_LIOur results demonstrate that responses in typically size-dependent behaviours may be decoupled from size changes, thereby allowing fitness maximisation in novel environments. The spatial scale of the behavioural responses to urbanization suggest contributions of both genetic adaptation and plasticity. Although fecundity decreased with local-scale urbanization, Araneus diadematus abundances were remarkably similar across urbanization gradients; behavioural responses thus appear overall successful at the population level.\nC_LI

ecology↗

bioRxiv2017

Bottom-up and top-down control of dispersal across major organismal groups: a coordinated distributed experiment

Organisms rarely experience a homogeneous environment. Rather, ecological and evolutionary dynamics unfold in spatially structured and fragmented landscapes, with dispersal as the central process linking these dynamics across spatial scales. Because dispersal is a multi-causal and highly plastic life-history trait, finding general drivers that are of importance across species is challenging but highly relevant for ecological forecasting.\n\nWe here tested whether two fundamental ecological forces and main determinants of local population dynamics, top-down and bottom-up control, generally explain dispersal in spatially structured communities. In a coordinated distributed experiment spanning a wide range of actively dispersing organisms, from protozoa to vertebrates, we show that bottom-up control, that is resource limitation, consistently increased dispersal. While top-down control, that is predation risk, was an equally important dispersal driver as bottom-up control, its effect depended on prey and predator space use and whether dispersal occurred on land, in water or in the air: species that routinely use more space than their predators showed increased dispersal in response to predation, specifically in aquatic environments. After establishing these general causes of dispersal, we used a metacommunity model to show that bottom-up and top-down control of dispersal has important consequences for local population fluctuations as well as cascading effects on regional metacommunity dynamics. Context-dependent dispersal reduced local population fluctuations and desynchronized dynamics between communities, two effects that increase population and community stability.\n\nOur study provides unprecedented insights into the generality of the positive resource dependency of dispersal as well as a robust experimental test of current theory predicting that predator-induced dispersal is modulated by prey and predator space use. Our experimental and theoretical work highlights the critical importance of the multi-causal nature of dispersal as well as its cascading effects on regional community dynamics, which are specifically relevant to ecological forecasting.

ecology↗

bioRxiv2017

The importance and adaptive value of life history evolution for metapopulation dynamics

O_LIThe spatial configuration and size of patches influence metapopulation dynamics by altering colonisation-extinction dynamics and local density-dependency. This spatial forcing as determined by the metapopulation typology then imposes strong selection pressures on life history traits, which will in turn feedback on the ecological metapopulation dynamics. Given the relevance of metapopulation persistence for biological conservation, and the potential rescuing role of evolution, a firm understanding of the relevance of these eco-evolutionary processes is essential.\nC_LIO_LIWe here follow a systems modelling approach to quantify the importance of spatial forcing and experimentally observed life history evolution for metapopulation demography as quantified by (meta)population size and variability. We therefore developed an individual based model matching an earlier experimental evolution with spider mites to perform virtual translocation and invasion experiments that would have been otherwise impossible to conduct.\nC_LIO_LIWe show that (1) metapopulation demography is more affected by spatial forcing than by life history evolution, but that life history evolution contributes substantially to changes in local and especially metapopulation-level population sizes, (2) extinction rates are minimised by evolution in classical metapopulations, and (3) evolution is optimising individual performance in metapopulations when considering the importance of more cryptic stress resistance evolution.\nC_LIO_LIEcological systems modelling opens up a promising avenue to quantify the importance of eco-evolutionary feedbacks for larger-scale population dynamics. Metapopulation sizes are especially impacted by evolution but its variability is mainly determined by the spatial forcing.\nC_LIO_LIEco-evolutionary dynamics can increase the persistence of classical metapopulations. The maintenance of evolutionary dynamics in spatially structured populations is thus not only essential in the face of environmental change; it also generates feedbacks that impact metapopulation persistence.\nC_LI\n\nData-archiveMetadata population dynamics in artificial metapopulations data are available from the Dryad Digital Repository: http://dx.doi.org/10.5061/dryad.18r5f (De Roissart, Wang & Bonte 2015). Modeling code is available on: https://github.ugent.be/pages/dbonte/eco_evo-metapop/ (ODD protocol in supplementary material)

evolutionary biology↗

bioRxiv2017

Kin competition as driver of range expansions

With ongoing global change, life is continuously forced to move to novel areas, which leads to dynamically changing species ranges. As dispersal is central to range dynamics, factors promoting fast and distant dispersal are key to understanding and predicting species ranges. During range expansions, genetic variation is depleted at the expanding front. Such conditions should reduce evolutionary potential, while increasing kin competition. Organisms able to recognise relatives may be able to assess increased levels of relatedness at expanding range margins and to increase their dispersal in a plastic manner. Using individual-based simulations and experimental range expansions of a spider mite, we demonstrate that plastic responses to kin structure can be at least as important as evolution in driving range expansion speed. Because recognition of kin or kind is increasingly documented across the tree of life, we anticipate it to be a highly important but neglected driver of range expansions.

ecology↗