Biology subjects

Weinbach, A.

Publications and source records attributed to Weinbach, A..

4 recordsLinked to original sources

bioRxiv2023

Eco-evolutionary dynamics in two-species mutualistic systems: One-sided population decline triggers joint interaction disinvestment

The interplay between ecological and evolutionary dynamics can create feedback that reinforces external disturbances and potentially threatens species coexistence. For example, plants might invest less into attracting insect pollinators (decreased flower or nectar production) and more into independence (increased selfing or vegetative reproduction) when faced with pollinator decline. This adaptive response saves plant resources at the cost of further threatening the pollinator population. We ask under which conditions such self-reinforcing feedback occurs in two-species mutualistic systems when considering one-sided population decline and whether it can be counteracted by self-dampening feedback if co-evolution of both interaction partners is considered. Based on a mathematical model and in line with previous studies, we find that the described pattern of accelerated population decline occurs for a wide range of parameter values if a concave allocation trade-off between independent growth and interaction investment is assumed. The undisturbed population typically disinvests first, which then forces the declining population to also disinvest, in favour of other energy sources. However, a decelerated population decline can occur if the adaptation of the undisturbed partner is relatively slow compared to environmental decay, reducing the speed of its disinvestment, or if the initial investment into the interaction was very high. Our results suggest that if actions are taken to save endangered populations, not only the evolution of the target species but also of their interaction partner, as well as the interaction between them should be considered.

ecology↗

bioRxiv2019

Collapse and rescue of evolutionary food webs under global warming

O_LIGlobal warming is severely impacting ecosystems and threatening ecosystem services as well as human well-being. While some species face extinction risk, several studies suggest the possibility that fast evolution may allow species to adapt and survive in spite of environmental changes. C_LIO_LIWe assess how such evolutionary rescue extends to multitrophic communities and whether evolution systematically preserves biodiversity under global warming. C_LIO_LIMore precisely, we expose simulated trophic networks of co-evolving consumers to warming under different evolutionary scenarios, which allows us to assess the effect of evolution on diversity maintenance. We also investigate how the evolution of body mass and feeding preference affects coexistence within a simplified consumer-resource module. C_LIO_LIOur simulations predict that the long-term diversity loss triggered by warming is considerably higher in scenarios where evolution is slowed down or switched off completely, indicating that eco-evolutionary feedback indeed helps to preserve biodiversity. However, even with fast evolution, food webs still experience vast disruptions in their structure and functioning. Reversing warming may thus not be sufficient to restore previous structures. C_LIO_LIOur findings highlight how the interaction between evolutionary rescue and changes in trophic structures constrains ecosystem responses to warming with important implications for conservation and management policies. C_LI

evolutionary biology↗

bioRxiv2019

Plant evolution further threatens declining pollinator populations

AO_SCPLOWBSTRACTC_SCPLOWWith current environmental changes, evolution can rescue declining populations, but what happens to their interacting species? Mutualistic interactions can help species sustain each other when their environment worsens. However, mutualism is often costly to maintain, and evolution might counter-select it when not profitable enough. We investigate how evolution of mutualism affects the coexistence of two mutualistic species, e.g. a plant-pollinator or plant-fungi system. Specifically, using eco-evolutionary dynamics, we study the evolution of the focal species investment in the mutualistic interaction of a focal species (e.g. plant attractiveness via flower or nectar production for pollinators or carbon exudate for mycorrhizal fungi), and how it is affected by the decline of the partner population with which it is interacting. We assume an allocation trade-off so that investment in the mutualistic interaction reduces the species intrinsic growth rate. First, we investigate how evolution changes species persistence, biomass production, and the intensity of the mutualistic interaction. We show that concave trade-offs allow evolutionary convergence to stable coexistence. We next assume an external disturbance that decreases the partner population by lowering its intrinsic growth rate. Such declines result in the evolution of lower investment of the focal species in the mutualistic interaction, which eventually leads to the extinction of the partner species. With asymmetric mutualism favouring the partner, the evolutionary disappearance of the mutualistic interaction is delayed. Our results suggest that evolution may account for the current collapse of some mutualistic system like plant-pollinator ones, and that restoration attempts should be enforced early enough to prevent potential negative effects driven by evolution.

ecology↗

bioRxiv2017

Selective effects of temperature on body mass depend on trophic interactions and network position

Body mass is a key trait constraining interspecific interactions in food webs through changes in metabolic requirements. Because climate warming affects metabolic rates, it creates direct selective effects on body mass. Many empirical studies suggest that body mass decreases under warming, although important exceptions have been noted. We first analyze the evolution of body mass in a simple consumer-resource model to provide conditions under which a body mass increase or decrease may be expected. We then extend our model to a multi-trophic food web context that allows for the coevolution of body mass and of feeding preferences. We focus here on how the trophic position of a consumer influences its evolutionary response to warming under different scenarios for the temperature dependence of attack rates. We observe that body masses can remain constant or increase with temperature when attack rates are constant or increasing with temperature, while body mass reductions in response to warming are only expected when attack rates have a thermal optimum and populations are initially locally adapted. We also found that body masses at lower trophic levels vary less under warming than body masses at higher trophic levels, which may be explained by decreasing levels of stabilizing selection along food chains.

ecology↗