Living in the branches: population dynamics and ecological processes in dendritic networks

Campbell Grant, Evan H., Winsor H. Lowe, and William F. Fagan. “Living in the branches: population dynamics and ecological processes in dendritic networks.” Ecology letters 10.2 (2007): 165-175.

We, as ecologists, are often interested in the population dynamics in complex spatial structures.  Here the authors review the currents paradigms for studying these complex systems, describe dendritic networks (which have hierarchical, branching geometry), recap the existing theory of the ecological dynamics of these networks, review the population and community consequences of dendritic networks, and discuss future research integrating spatial pattern and processes in these networks.

“Dendritic” means geometric patterns of arborescent, which consists of a mainstem and branches that decrease in size and number as one moves up through the network. More generally, dendritic can describe any system where critical resources are concentrated in a linear arrangement and where these units intersect to create a branching structure. An example of these is the branches of individual plants, river network systems or caves. In these networks, both the nodes and edges are habitat for the population. Unlike other network structures (such as lattice), the edges are the primary habitat for the population. The movement of individual occurs along the branches. In lattice networks, the movements occurs between patches with individuals only using the edges as a pathway between patches.

The theoretical studies in spatially structured networks have focus on statistical measures of network properties that include the large-scale connectivity and the network persistence of populations and communities.  Dendritic networks result ecological processes that are sensitive to specific structural features (Figure 2). The branching, hierarchical geometry of dendritic networks drive patterns and functional properties of populations.

For future investigations, the authors point out the characteristics of dendritic networks that are of interest: number of branch intersections, size and shape of branches, and the hierarchical geometry of branching. Future investigations (proposed in 2007) include: considering movement within and out-of-network, natural versus man made dendritic networks, the species adaptation to the geometry, when does geometry matter, and understanding how these networks form.