Biology subjects

Villain, T.

Publications and source records attributed to Villain, T..

5 recordsLinked to original sources

bioRxiv2026

Direct and community-driven selection jointly drive body size evolution in harvested predator-prey systems

Fisheries-induced evolution (FIE) affects multiple life-history traits, most notably body size. This evolutionary response is often examined at the single-species level and attributed to direct size-selective harvesting. However, fishing also targets other community members, reshaping trophic interactions and thereby modifying evolutionary constraints due to community changes. Here, we disentangle two forms of fishing-induced selection on body size - direct, arising from size-selective harvesting within species individuals, and indirect, emerging from fishing-induced changes in community structure - and investigate how their interplay shapes evolutionary trajectories. Using an adaptive dynamics framework within a predator-prey model, we show that (i) community destructuring can either amplify or dampen the effects of intraspecific size-selectivity on body-size evolution, (ii) predator evolution is primarily driven by direct selection, whereas prey evolution is mostly constrained indirectly by community structure. We then extend our analysis using a stochastic framework and show that (iii) prey evolution allows the evolutionary rescue of predators, underscoring the importance of community context. Our results demonstrate that eco-evolutionary feedbacks can profoundly alter both community structure and fishery yields, strengthening calls to incorporate evolution into ecosystem-based fisheries management.

evolutionary biology↗

bioRxiv2026

Potential and limits of the evolutionary rescue of harvested food webs

Fishing deeply alters marine food webs structure and can drive the evolution of species traits, whether the species are directly targeted or not. Yet, studies rarely account for fisheries-induced evolution, and consequences are generally interpreted at the single-species level. Theory however predicts that eco-evolutionary dynamics within food webs can either promote biodiversity maintenance or accelerate its decline. In this study, we investigate how evolution affects the robustness of trophic networks under fishing pressure. Modifying evolution speed and the allocation of fishing effort across 458 structurally distinct allometric networks enables us to show that evolution most often enhances robustness. Network evolutionary response however becomes more variable (and possibly negative) as evolutionary rates increase and when fishing preferentially targets predators. By contrast, fishing strategies that concentrate effort on lower trophic levels, or distribute it more evenly, promote network persistence through evolutionary rescue while substantially reducing the risk of evolutionary collapse. Moreover, our results appear to be sensitive to the main forces governing ecological dynamics within the network such as competition or predation intensity. Finally, the consequences of network evolution differ across trophic levels. Evolution often drives the collapse of higher trophic levels while simultaneously promoting evolutionary rescue and enhancing diversity at lower levels through increased diversification, thereby generating a trade-off between vertical diversity (number of trophic levels) and total diversity. This highlights the importance of accounting for evolutionary dynamics and food web functioning in fisheries management, and suggests that reducing predator mortality may help prevent network evolutionary collapse.

evolutionary biology↗

bioRxiv2026

Applying a metaweb approach to reserve design: large, well protected areas are crucial to maintain food webs

Establishing protected areas is a promising tool to address the accelerating loss of biodiversity. However, protection levels are often low, and there is an ongoing debate over the most effective spatial configuration of reserves. This debate rarely considers trophic structure and ignores biodiversity outside protected areas. In this study, we investigate which reserve configurations best support species diversity and the persistence of high trophic levels, across systems and spatial scales, both inside and outside protected areas. Using a spatially explicit stochastic model, we assess how reserve architecture influences multiple conservation objectives across 27 empirical terrestrial, freshwater, and marine food webs. Specifically, we explore reserve architecture along three dimensions: the aggregation of protected areas, their proportion at the landscape scale, and the effectiveness level of protection measures. Our results show that having few but larger protected areas enhances all conservation metrics within reserves, while diversity within and outside reserves is relatively insensitive to reserve aggregation. Smaller and more dispersed reserves improve the overall abundance of species off-reserves through spillover effects. Reconciling all objectives inside and outside reserves becomes feasible when protection effectiveness is sufficiently high. Increasing the efficiency of protection allows for a reduction in the total amount of protected land without compromising conservation outcomes. Moreover, higher species dispersal facilitates the achievement of multiple conservation goals, supporting the implementation of architectures that enhance connectivity among reserves. These findings highlight the importance of an integrated approach combining spatial ecology and trophic functioning to optimize protected area planning under multiple objectives.

ecology↗

bioRxiv2026

Eco-evolutionary dynamics of planktonic calcifying communities under ocean acidification

Increasing emissions of CO2 into the atmosphere are causing ocean acidification, threatening calcifying organisms. In this study, we model the physiological responses of coccolithophorids to acidification to understand the ecological and evolutionary outcomes of a system in interaction with zooplankton. Assuming a trade-off between growth and protection against grazing, we show that calcification has bivalent effects on transfers between two trophic levels and that acidity can strongly alter energy transfers. Taking into account the evolution of calcifying phenotypes in response to acidification, we show that the system outcome contrasts with previous results. While the effect of evolution depends on how calcification affects grazing, it nevertheless follows that acidification leads to a decrease in calcifying capacity. This evolutionary decrease may be progressive, but can also lead to tipping points where abrupt shifts may occur. Such a counter-selection of calcification in turn affects ecosystem functioning, enhancing energy transfers within the system and modifying carbon fluxes. We discuss how such eco-evolutionary changes may impact food webs integrity, carbon sequestration into the deep ocean and therefore endanger the carbon pump stability.

evolutionary biology↗

bioRxiv2025

Managing risks and trade-offs in multispecies fisheries: the role of trophic control and price asymmetry

Ecosystem-based fisheries management (EBFM) aims to balance ecological and economic goals while employing precautionary measures to address uncertainties in knowledge and management. This study investigates fishing strategies to achieve this balance while minimizing the associated risks. Using a simplified prey-predator model, we explored various scenarios reflecting the diversity of global fisheries. The model integrates key ecological dynamics (bottom-up and top-down forces), economic factors (price structures), and aggregates the diversity of fishing practices by distributing fishing mortality across species. Our findings reveal that predators are always more affected by fishing than prey, regardless of the effort distribution. High yields are achieved by reducing predator densities--either maximizing predator catches when they are highly valued or reducing predation pressure to enhance prey harvests when prey prices are high. Such strategies result in significant ecological impacts, leading to systematic trade-offs. Elevated prey prices and top-down controlled systems intensify these trade-offs, increasing ecological risks. Regarding uncertainties, we demonstrate that maximizing yields poses risks to both biodiversity and profitability. Reconciliation is challenging but feasible when both species are fished. This balance can be achieved only in bottom-up controlled systems where prey valuation is not disproportionately high compared to predator prices.

ecology↗