Strange invaders increase disturbance and promote generalists in an evolving food web

Jonathan R Morris,Korinna T Allhoff,Fernanda S Valdovinos

doi:10.1038/s41598-021-99843-3

Jonathan R Morris, Korinna T Allhoff + Show 1 more

Open Access

https://doi.org/10.1038/s41598-021-99843-3

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Abstract

The patterns of diet specialization in food webs determine community structure, stability, and function. While specialists are often thought to evolve due to greater efficiency, generalists should have an advantage in systems with high levels of variability. Here we test the generalist-disturbance hypothesis using a dynamic, evolutionary food web model. Species occur along a body size axis with three traits (body size, feeding center, feeding range) that evolve independently and determine interaction strengths. Communities are assembled via ecological and evolutionary processes, where species biomass and persistence are driven by a bioenergetics model. New species are introduced either as mutants similar to parent species in the community or as invaders, with dissimilar traits. We introduced variation into communities by increasing the dissimilarity of invading species across simulations. We found that strange invaders increased the variability of communities which increased both the degree of generalism and the relative persistence of generalist species, indicating that invasion disturbance promotes the evolution of generalist species in food webs.

Highlights

The patterns of diet specialization in food webs determine community structure, stability, and function
Do resource and community variation increase with invader strangeness? Adding increasingly strange invaders into simulated evolutionary food webs increased the variability of communities
The mechanisms we evaluated include the impact of disturbance caused by invasion on populations interacting via consumer-resource and competitive interactions at a community scale, and the evolution of foraging traits of resident species under those conditions through mutation and extinction

Summary

Introduction

The patterns of diet specialization in food webs determine community structure, stability, and function. Despite the trade-offs in efficiency assumed for generalists, it is widely hypothesized that species consuming a wider range of resources will be favored over specialists when environments are more variable, making specific resources difficult to a cquire[1,11]. This generalist-disturbance hypothesis suggests that communities with higher levels of environmental and community variability across time should be comprised of greater proportions of generalist species that can withstand variability by relying on other available resources when specialist species cannot. Variation (disturbance) Specialists vs. generalists Fundamental feeding range (s) Realized feeding range (Proportion of community consumed) Species persistence (lifespan)

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