Meta communities in dynamic systems

Submitted by editor on 16 October 2015.Get the paper!

Biological communities are shaped by both local biotic interactions and abiotic environmental conditions (environmental filtering) and regional processes, such as the movement of organisms from one site to another (dispersal). Following this, how sets of local biological communities -or metacommunities- are spatially organised across landscapes and what is the respective role of local and regional processes for this organisation have been documented in various terrestrial, marine and freshwater ecosystems. However, how these processes and subsequent metacommunity organisation vary over time in ecosystems whose habitat characteristics, configuration and composition shift constantly remains an open question. To explore this, we used as a model intermittent rivers, those rivers which temporarily cease flowing and occur abundantly in all climates and continents. In addition of being composed of flowing, non-flowing and dry habitats in constant re-arrangement, intermittent river networks are colonised by aquatic and terrestrial species which can interact strongly.

An intermittent stream located in the Jura mountain of France (La Clauge) during the dry (summer) and wet (autumn) phases. Photos: B. Launay.

We developed the idea that metacommunities in intermittent rivers and other dynamic ecosystems may undergo frequent shifts in structure and composition in response to the temporal variability of the respective role of environmental filtering and dispersal. For example, during initial drying phases and shifts from lotic (flowing waters) to lentic (stagnant waters) conditions, environmental filtering may predominate and lead to the elimination of lotic species. In contrast, during rewetting event[a1] s, dispersal of terrestrial and aquatic organisms throughout the river network may temporarily be the most significant community process. Hence, local community structure along with spatial metacommunity patterns may constantly change in dynamic ecological systems. In addition to providing a roadmap for developing dynamic community ecology, these ideas provide insights to improve the management of intermittent river other dynamic ecosystems.

Take a look at the videos showing rewetting events in some intermittent rivers

 

 

 

The authors through Thibault Datry

 

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