title: Time-variant species pools shape competitive dynamics and biodiversity-ecosystem function relationships.
abstract: Biodiversity-ecosystem function (BEF) experiments routinely employ common garden designs, drawing samples from a local biota. The communities from which taxa are sampled may not, however, be at equilibrium. To test for temporal changes in BEF relationships, I assembled the pools of aquatic bacterial strains isolated at different time points from leaves on the pitcher plant Darlingtonia californica in order to evaluate the strength, direction and drivers of the BEF relationship across a natural host-associated successional gradient. I constructed experimental communities using bacterial isolates from each time point and measured their respiration rates and competitive interactions. Communities assembled from mid-successional species pools showed the strongest positive relationships between community richness and respiration rates, driven primarily by linear additivity among isolates. Diffuse competition was common among all communities but greatest within mid-successional isolates. These results demonstrate the dependence of the BEF relationship on the temporal dynamics of the local species pool, implying that ecosystems may respond differently to the addition or removal of taxa at different points in time during succession.
authors.affiliation: Department of Integrative Biology, University of California Berkeley, 3040 Valley Life Sciences Building, Berkeley, CA 94720-3140, USA Department of Biological Sciences, University of Notre Dame, 100 Galvin Life Science Center, Notre Dame, IN 46556, USA dave.armitage@gmail.com.
authors.forename: David W
authors.identifier: 0000-0002-5677-0501
authors.initials: DW
authors.lastname: Armitage
mesh_terms: D001419:Bacteria / Q000145:classification*; D044822:Biodiversity; D017753:Ecosystem; D011157:Population Dynamics; D052583:Sarraceniaceae / Q000382:microbiology*
keywords: bacteria; biodiversity–ecosystem function; competition; pitcher plant; succession; time