Document: TAD-3-67-6

An experimentally-derived community assembly map.

FUKAMI, T.*, C.R.ZIMMERMANN, N.Z.MUTH and J.A.DRAKE

University of Tennessee, Knoxville, TN 37996 USA ¹

Abstract:
Laboratory microcosm experiments in community assembly have shown that the timing and sequence of invading species can play a strong influential role in community development. Here, we construct a comprehensive map of community assembly dynamics through synthesis of our results from multiple freshwater microcosm experiments. In doing so, we have exposed some of the underlying rules which shape the topology of the assembly landscape in both time and space. This map shows that numerous attractors which govern community development and organization can arise from the historical effects induced by assembly processes. Bifurcations in the trajectories of developing communities can arise when invading speces - through species interactions (e.g. predation, competition, facilitation) and/or biologically-mediated modification of the physical environment - can impact the vigor/fecundity of resident species or the invasion capability of subsequent invaders. Some trajectories result in the development of both invasible and noninvasible assemblages. In addition, some portions of the assembly map appear to be deterministic - such that the same community state is consistently produced - while others appear indeterministic. Density maxima and minima as well as holes - depicting possible forbidden species combinations - are present on our map which indicate in probabilistic fashion which trajectories and community states are most likely visited as development proceeds. Apart from the obvious theoretical implications, such maps - if extendable to natural systems - could be valuable for field ecologists working in ecosystem management and restoration.

Keywords: assembly rules, alternative states, invasions

This abstract is being presented at: 10:30 AM in session:
Poster Session #9: Fish, Lakes, Streams and Wetlands.