Biotic resistance shapes the influence of propagule pressure on invasion success in bacterial communities

Abstract

Abstract. The number of invaders and the timing of invasion are recognized as key determinants of successful invasions. Despite the recognized importance of "propagule pressure," invasion ecology has largely focused on how characteristics of the native community confer invasion resistance. We simultaneously manipulated community composition and invader propagule pressure in microcosm communities of freshwater bacteria. We show that high propagule pressures can be necessary to establish an invader population, but that the influence of propagule pressure depends on the composition of the resident species. In particular, the number of individuals invading was most important to invasion success when one of the species in a resident community is a strong competitor against other species. By contrast, the timing of invasion was most important when communities had lower growth rates. The results suggest that the importance of propagule pressure varies both between communities and within the same community over time, and therefore have implications for the way we understand the relationship between biotic resistance and invasion success.

Elevated success of multispecies bacterial invasions impacts community composition during ecological succession

“…The outer arrows are the pairwise invasions, whereas the arrows radiating from the central 'ABC' show the impact of removing any of the 3 species from the 3 species mixture. invasion resistance in low diversity microbial communities is determined by community composition (Jousset et al 2011;Jones et al 2017), potentially because of differences in interspecific interaction networks that develop in different communities (Coyte et al 2015) as predicted from theory (HilleRisLambers et al 2012). Increasing positive interactions within communities during succession have also been observed in plants (Tilman et al 2001), animals (Vermeij 1991), and in theoretical work (Gilpin 1994;Tikhonov 2016).…”

“…; Jones et al . ), potentially because of differences in interspecific interaction networks that develop in different communities (Coyte et al . ) as predicted from theory (HilleRisLambers et al .…”

“…The invaders were selected and isolated based on their cosmopolitan distribution across tree holes and aerobic culturability. Previous work using the same system (Fiegna et al 2015;Rivett et al 2016;Jones et al 2017) has demonstrated shifting resource usage during community succession. We predicted a decline in the importance of complementarity among invader species during succession because declines in resource availability would provide fewer opportunities for complementarity.…”

“…; Jones et al . ) has demonstrated shifting resource usage during community succession. We predicted a decline in the importance of complementarity among invader species during succession because declines in resource availability would provide fewer opportunities for complementarity.…”

Biogeography at the limits of life: Do extremophilic microbial communities show biogeographical regionalization?

“…Furthermore, the deposition of cells from ancient halite into modern hypersaline environments would be most likely to occur over regional extents (e.g., owing to oceanic currents), thus increasing the compositional similarity of sites within a region. Finally, even with connectivity between ancient and modern halite, there is no guarantee that those cells will become established and multiply (Jones, Ramoneda, Rivett, & Bell, ). Therefore, the influence of ancient haloarchaea on the clustering patterns observed here should be minimal.…”