Multi‐trophic metacommunity interactions mediate asynchrony and stability in fluctuating environments

Abstract

Environmental fluctuations influence patterns of synchrony and stability in species abundances. Most of our understanding of synchrony and stability stems from competitive community and metacommunity ecology, when in reality species interact in more complex ways. Therefore, there is a mounting need for the integration of multi-trophic interactions into metacommunity ecology. In particular, knowledge is lacking on: (1) whether synchrony and stability respond to environmental fluctuations similarly under competitive and multi-trophic metacommunities; (2) how synchrony and stability change across the hierarchical levels of a metacommunity; and (3) whether trophic groups differ in their contributions to synchrony and stability. Here, we address these questions through a complementary approach, using model simulations to derive theoretical expectations for the effects of environmental fluctuations on synchrony and stability, and a microcosm experiment to test observations against these expectations. We created spatially heterogeneous metacommunities populated by eight protist and one rotifer species organized in a multi-trophic food-web. We controlled environmental fluctuations so that they were spatially uncorrelated and species were assumed to respond differently to environmental conditions. We contrasted the control of constant environmental conditions to the effects of periodic environmental fluctuations. We show that environmental fluctuations can reduce synchrony between patches and increase stability, but can also decouple asynchrony between species and increase population and metapopulation variability. We discuss how some of these findings apply to both competitive and multi-trophic metacommunities but changes are stronger in multi-trophic metacommunities, and how trophic groups differ in their contributions to synchrony and variability.

Temporal variability declines with increasing trophic levels and spatial scales in freshwater ecosystems

“…Interestingly, at the local scale, the amount of variability propagated from the population to the community level was higher for tertiary consumers because fluctuations in abundances of tertiary species were highly synchronized locally, while the opposite manifested at the regional scale. Populations of higher trophic levels tend to congregate together on specific resource patches within the metacommunity while they are profitable 21 , which explains the highest levels of local population synchrony among tertiary consumers, a result also supported by microcosm research 9 . The local synchronizing effect of top consumers appears to weaken along the trophic chain within communities, leading to lower population synchrony within primary consumers and producers.…”

“…Ecological stability propagates across spatial scales and trophic levels in freshwater ecosystems Tadeu Siqueira 1,2* , Charles P. Hawkins 3 , Julian D. Olden 4 , Jonathan Tonkin 5 , Lise Comte 6 , Victor S. Saito 7 , Thomas L. Anderson 8 , Gedimar P. Barbosa 1 ; Núria Bonada 9 , Claudia C. Bonecker 10 , Miguel Cañedo-Argüelles 9,11 , Thibault Datry 12 , Michael B. Flinn 13 , Pau Fortuño 9 , Gretchen A. Gerrish 14 , Peter Haase 15 , Matthew J. Hill 16 , James M. Hood 17 , Kaisa-Leena Huttunen 18 , Michael J. Jeffries 19 , Timo Muotka 20…”

“…However, most previous attempts to understand temporal variability and its drivers have done so at single trophic levels 1,[5][6][7] , resulting in a critical knowledge gap. Communities are connected to each other through the spatial flow of organisms in different trophic levels 8 ; thus, the spatial structure of multitrophic metacommunities may modulate temporal variability 9 . For example, mobile top consumers can buffer temporal variability of an entire metacommunity if they move unhindered across the landscape, optimally foraging across heterogeneous resource patches that have asynchronous dynamics 10 .…”

Predation, community asynchrony, and metacommunity stability in cyanobacterial mats

“…Predation pressure can be an important force toward preventing synchrony among communities and promoting compensatory oscillatory dynamics in metacommunities, even in systems with strongly synchronizing dispersal (Howeth and Leibold 2013). However, the extent of these effects depends strongly upon predator niche, distribution of predation pressure in time and space, and context of abiotic environmental variability, as predators can antithetically promote species and spatial patch synchrony via spatial coupling of dynamics (Howeth and Leibold 2010, 2013, Firkowski et al 2022. The documented spatial heterogeneity in experienced predation pressure from generalist mobile reef fishes across mat communities may significantly contribute to the maintenance of asynchrony in the dynamics of component communities in this cyanobacterial mat system via the creation of spatiotemporal complementarity in patterns of mat senescence (Fig 1b).…”

“…The copyright holder for this preprint this version posted October 9, 2022. ; https://doi.org/10.1101/2022.10.07.511315 doi: bioRxiv preprint understanding of mat metacommunity dynamics is critical, especially considering the increasingly dramatic environmental fluctuations experienced on reefs (i.e. massive pulse nutrient loadings; Firkowski et al 2022). Trophic interactions may be a strong local-scale generator of asynchrony in community dynamics despite regional spatially synchronizing effects resulting from spatially correlated responses to environmental fluctuations driven by relatively low beta diversity among local mat communities (Cissell and McCoy in review), helping to maintain persistent mat cover at the scale of reef site.…”