Disturbance regime alters the impact of dispersal on alpha and beta diversity in a natural metacommunity

Abstract

Disturbance and dispersal are two fundamental ecological processes that shape diversity patterns, yet their interaction and the underlying mechanisms are still poorly understood, and evidence from natural systems is particularly lacking. Using an invertebrate rock pool metacommunity in South Africa as a natural model system, we studied potential interactive effects of disturbance regime and patch isolation on diversity patterns of species with contrasting dispersal modes (passive vs. active dispersal). Isolation and disturbance regime had negative synergistic effects on alpha diversity: both directly, by excluding late-successional species from isolated patches; and indirectly, by modulating establishment success of generalist predators in well-connected patches. Unimodal relationships between isolation and alpha diversity, as predicted by mass effects, were only detected for passive dispersers in frequently disturbed patches and not in active dispersers. For passive dispersers, indications for a positive effect of isolation and a negative effect of disturbance on beta diversity were found, presumably due to differences in deterministic succession and stochastic colonization-extinction dynamics among different patch types. Our findings illustrate that interactions between dispersal rates and disturbance regime are important when explaining species diversity patterns in metacommunities and support the idea that diversity in frequently disturbed habitats is more sensitive to effects of dispersal-based processes.

Hydrological stability drives both local and regional diversity patterns in rock pool metacommunities

“…Analogous to the pattern observed at the metacommunity level, communities in less stable habitats were nested in communities in more stable habitats. This suggests that community membership gradually becomes more restricted as conditions become less stable resulting in species loss, as was the case in other systems (Therriault and Kolasa , Vanschoenwinkel et al ). It is clear, however, that nestedness does not account for all variation in community composition.…”

Disturbance alters beta‐diversity but not the relative importance of community assembly mechanisms

“…Disturbance often has variable effects on β‐diversity (Chase ; Vellend et al . ; Jiang & Patel ; Belote, Sanders & Jones ; Myers & Harms ; Tonkin & Death ; Vanschoenwinkel, Buschke & Brendonck ). Although it is tempting to invoke different community assembly processes to explain variation in β‐diversity within and among studies, we suggest that the results from most studies of β‐diversity cannot be used to unambiguously identify changes in assembly mechanisms that influence clumping of species in disturbed and undisturbed landscapes.…”

“…Chase ; Vellend et al . ; Jiang & Patel ; Belote, Sanders & Jones ; Myers & Harms ; Tonkin & Death ; Vanschoenwinkel, Buschke & Brendonck ). A richer understanding of the mechanisms by which disturbance alters β‐diversity would not only help advance community assembly theory, but also our knowledge of how to preserve and restore biodiversity in human‐modified ecosystems.…”

How individual links affect network stability in a large‐scale, heterogeneous metacommunity

“…For example, metacommunity ecology has demonstrated important ways in which dispersal among numerous patches affects both local and regional diversity, as well as the stability of the entire network (Leibold et al 2004, Holyoak et al 2005, Logue et al 2011. A greater understanding of larger-scale metacommunity systems in nature remains a critical need (Logue et al 2011, Vanschoenwinkel et al 2013, Simonis and Ellis 2014. A greater understanding of larger-scale metacommunity systems in nature remains a critical need (Logue et al 2011, Vanschoenwinkel et al 2013, Simonis and Ellis 2014.…”