Nauta, J. | bioRxiv Science

bioRxiv2025

Species interactions determine plasmid persistence in a 3-member bacterial community

Microbial communities are shaped by multiple forces, including interspecies interactions and the effects of mobile genetic elements such as plasmids. How these forces interact to affect community responses to environmental perturbations remains unclear, particularly considering the qualitatively different natures and the complexity of competitive and plasmid transfer interactions. We investigated the role of bacterial and plasmid interaction networks in community responses to single and multiple environmental perturbations, using a model community of three bacteria and two plasmids grown in rich media over five 2-day transfers. Bacterial interactions were the primary driver of community response, to the extent that plasmids were not always retained in the community even when they carried relevant resistance genes. Overall, our results indicate that while bacterial and plasmid interactions both shape community responses to environmental perturbations, bacteria-bacteria interactions may be the primary driver of community dynamics and their response to perturbations.

ecology↗

bioRxiv2021

Foraging behavior and patch size distribution jointly determine population dynamics in fragmented landscapes

Increased fragmentation caused by habitat loss represents a major threat to the persistence of animal populations. How fragmentation affects populations depends on the rate at which individuals move between spatially separated patches. Whereas negative effects of habitat loss on biodiversity are well-known, effects of fragmentation per se on population dynamics and ecosystem stability remain less understood. Here, we use a spatially explicit predator-prey model to investigate how the interplay between fragmentation and optimal foraging behavior affects predator-prey interactions and, subsequently, ecosystem stability. We study systems wherein prey occupies isolated patches and are consumed by predators that disperse following Levy random walks. Our results show that the Levy exponent and the degree of fragmentation jointly determine coexistence probabilities. In highly fragmented landscapes, Brownian and ballistic predators go extinct and only scale-free predators can coexist with prey. Furthermore, our results confirm that predation causes irreversible habitat loss in fragmented landscapes due to overexploitation of smaller patches of prey. Moreover, we show that predator dispersal can reduce, but not prevent nor minimize, the amount of lost habitat. Our results suggest that integrating optimal foraging theory into population- and landscape ecology is crucial to assessing the impact of fragmentation on biodiversity and ecosystem stability.

ecology↗