PARENT SESSION
Contributed Oral Session 33: Grassland and Shrubland Communities
Monday, August 8, 1:30 PM - 5:00 PM, Meeting Room 522 A, Level 5, Palais des congrès de Montréal
Trait-based assembly rules govern grassland succession despite species divergence.
Fukami, Tadashi*,1, 2, Bezemer, T. Martijn2, 3, Mortimer, Simon4, van der Putten, Wim2, 3, 1 Landcare Research, Lincoln, New Zealand2 Netherlands Institute of Ecology, Heteren, The Netherlands3 Wageningen University & Research Centre, Wageningen, The Netherlands4 University of Reading, Reading, UK
ABSTRACT- The succession of species in ecosystems is one of the most important yet controversial topics in ecology. The degree to which succession is deterministic, convergent, and predictable has been vigorously debated for nearly a century. In this study, we provide the first experimental evidence, to our knowledge, that succession can simultaneously be predictable and unpredictable. We manipulated initial plant species composition on abandoned arable land in the Netherlands and subsequently allowed natural colonization over nine years. We show that initial compositional variation causes plant communities to follow divergent pathways of succession in species composition. Such divergence makes succession appear strongly unpredictable. However, these same communities exhibit striking patterns of convergence in the composition of trait-based groups of plant species, indicating highly deterministic assembly rules. This contrast between species divergence and trait convergence is attributable to priority effects involving inhibition or facilitation rather than to statistical inevitability, dispersal limitation, or community neutrality. These results have profound implications for restoration of biodiversity: restoring specific species compositions may require detailed knowledge of how initial community states determine the direction of ecosystem assembly, even when communities converge predictably in species traits.
Key words: community assembly, succession predictability, priority effects, restoration