Recent advances in metacommunities and meta-ecosystem theories

Abstract

Metacommunity theory has provided many insights into the general problem of local versus regional control of species diversity and relative abundance. The metacommunity framework has been extended from competitive interactions to whole food webs that can be described as spatial networks of interaction networks. Trophic metacommunity theory greatly contributed to resolving the community complexity-stability debate by predicting its dependence on the regional spatial context. The meta-ecosystem framework has since been suggested as a useful simplification of complex ecosystems to apply this spatial context to spatial flows of both individuals and matter. Reviewing the recent literature on metacommunity and meta-ecosystem theories suggests the importance of unifying theories of interaction strength into a meta-ecosystem framework that captures how the strength of spatial, species, and ecosystem fluxes are distributed across location and trophic levels. Such integration predicts important feedback between local and regional processes that drive the assembly of species, the stability of community, and the emergence of ecosystem functions, from limited spatial fluxes of individuals and (in)organic matter. These predictions are often mediated by the maintenance of environmental or endogenous fluctuations from local to regional scales that create important challenges and opportunities for the validation of metacommunity and meta-ecosystem theories and their application to conservation.

Keywords: conservation; ecosystem theories; metacommunities.

Figure 1.. Role of spatial interaction strength across trophic levels for dispersal-diversity relationships and for regional stability.

( A) Diversity–dispersal relationships. (a) Consumer dispersal α varies while keeping resource dispersal β small. (b) Consumer dispersal α and resource dispersal β vary simultaneously. (c) Resource dispersal β varies while keeping consumer dispersal α small. Thick line: local diversity; thin line: regional diversity. Reprinted with permission from John Wiley & Sons, Inc. . ( B) Changes in qualitative dynamics in a two-patch tri-trophic meta-ecosystem from varying resource intra-specific interaction strength (β) and dispersal rates, holding all other parameters constant. At intermediate levels of β, making dispersal more non-hierarchical by decreasing middle-trophic-level dispersal rates ( d _H) leads to increased stability because of the emergence of stable asymmetric equilibria. Reprinted with permission from the University of Chicago Press Books .

Figure 2.. From metacommunities to meta-ecosystems: cycling of matter across spatial networks of interaction networks.

Conceptual diagram for a general meta-ecosystem model that can predict the role of interaction strength between species and between locations for the exchange of individuals and matter. Local ecosystems (circles) have internal dynamics based on trophic (solid arrows) and non-trophic (dashed arrows) interactions between ecosystem compartments, which in this case are a limiting nutrient (R), autotrophs (A) and herbivores (H). Local ecosystems form a meta-ecosystem through the movement of materials and organisms, which is determined by the connectivity matrix C and the movement matrix D. The connectivity matrix indicates how the ecosystems are connected to one another (rectangular boxes), whereas the movement matrix gives the movement rates of each ecosystem compartment (two-headed arrows). Without a connection specified by the connectivity matrix, materials and organisms cannot move between ecosystems (capital X). Reprinted with permission from Elsevier .