Higher order interactions and species coexistence

Pragya Singh,Gaurav Baruah

doi:10.1007/s12080-020-00481-8

Abstract

Higher order interactions (HOIs) have been suggested to stabilize diverse ecological communities. However, their role in maintaining species coexistence from the perspective of modern coexistence theory is not known. Here, using generalized Lotka-Volterra model, we derive a general rule for species coexistence modulated by HOIs. We show that where pairwise species interactions fail to promote species coexistence in regions of extreme fitness differences, negative HOIs that intensify pairwise competition, however, can promote coexistence provided that HOIs strengthen intraspecific competition more than interspecific competition. In contrast, positive HOIs that alleviate pairwise competition can stabilize coexistence across a wide range of fitness differences, irrespective of differences in strength of inter- and intraspecific competition. In addition, we extend our three-species analytical result to multispecies communities and show, using simulations, that multispecies coexistence is possible provided that strength of negative intraspecific HOIs is higher than interspecific HOIs. Our work sheds light on the underlying mechanisms through which HOIs can maintain species diversity.

Highlights

IntroductionSpecies interact with other species in the community temporally (Li and Chesson 2016) and/or spatially (Hart et al 2017)
In diverse ecological communities, species interact with other species in the community temporally (Li and Chesson 2016) and/or spatially (Hart et al 2017)
Negative interspecific Higher order interactions (HOIs) were sampled from random – U (0.01, 0.09) and negative intraspecific HOIs were sampled from random – U (0.01 + d, 0.09 + d), where d increased from − 0.15 to 0.15 in steps of 0.05, such that when d = − 0.15, interspecific HOIs sampled are strictly of greater magnitude than intraspecific HOI, and when d = 0.15, magnitude of intraspecific HOIs is strictly greater than interspecific HOIs

Summary

Introduction

Species interact with other species in the community temporally (Li and Chesson 2016) and/or spatially (Hart et al 2017). In species-rich communities, underlying processes that cannot be captured by pairwise species interactions can emerge, and have been suggested to promote species coexistence (Abrams 1983). Such underlying processes, for example can be intransitive or “rock-paper-scissors” interactions (Laird and Schamp 2006; Gallien et al 2017; Saavedra et al 2017). Intransitive interactions are inherently pairwise in nature but they form interaction chains that favour species coexistence In such three species systems, there is the possibility of interactions among species to be not pairwise in nature.

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Conclusion