Effects of connectivity, dispersal directionality and functional traits on the metacommunity structure of river benthic diatoms
Article first published online: 15 JUL 2013
© 2013 John Wiley & Sons Ltd
Journal of Biogeography
Volume 40, Issue 12, pages 2238–2248, December 2013
How to Cite
Liu, J., Soininen, J., Han, B.-P., Declerck, S. A. J. (2013), Effects of connectivity, dispersal directionality and functional traits on the metacommunity structure of river benthic diatoms. Journal of Biogeography, 40: 2238–2248. doi: 10.1111/jbi.12160
- Issue published online: 20 NOV 2013
- Article first published online: 15 JUL 2013
- National Natural Science Foundation of China. Grant Number: 30970467
- Chinese Major Science and Technology Program for Water Pollution Control and Treatment. Grant Number: 2009ZX07211-009
- Asymmetric eigenvector maps;
- dendritic ecological network;
- metacommunity theory;
- Moran's eigenvector maps;
- overland dispersal;
- spatial dynamics;
- subtropical river
Dendritic ecological networks (DENs), such as river systems, combine features that challenge the traditional conceptual views and empirical approaches applied to metacommunities. As a result of their dendritic branching geometry and stream flow directionality, they are strongly hierarchical and asymmetrical. We analysed the metacommunity structure of benthic diatoms in a large-scale river system with the aim of evaluating the importance of potential causal influences. Furthermore, we hypothesized that metacommunities of diatoms that are strongly attached to their substrata show a different spatial structure than metacommunities of other, more weakly attached diatoms.
The study was carried out in the Dong River, a 32,275 km2 subtropical river network located in southern China.
We surveyed benthic diatom communities during three seasons (dry, intermediate and wet). Using partial redundancy analysis, we partitioned community variation among environmental models and different spatial eigenfunction models to evaluate the influence of alternative dispersal pathways (overland versus water course dispersal), stream directionality, man-made dams and diatom functional traits on diatom metacommunity structure.
Models based on hydrological connections and water directionality represent spatial patterns better than overland distances, suggesting that the dynamics of benthic diatom metacommunities are mainly confined to the river network and influenced by the prevailing water flow. We found significant effects of man-made dams on the spatial structure of important limnological variables and diatom metacommunity structure. The metacommunity of strongly attached diatoms also showed a weaker signature of flow directionality than that of other growth forms, especially in seasons with high water levels.
We conclude that the consideration of among-site connectivity, flow directionality and species traits is key to a better understanding of the spatial ecology of passively dispersing microbial organisms in river systems.