Abstract Detail

Ecology/Pathology

Maynard, Daniel S. [1], Crowther, Thomas W. [1], Leonard, Kenneth E. [2], Bradford, Mark A [1].

Predicting the realized niche by modeling fungal competitive ability.

Competition is a dominant process structuring fungal communities, yet the myriad ways in which fungi compete and the high diversity of fungi in many ecosystems hinder attempts to predict competitive outcomes from individual species’ performances. We present a conceptual and mathematical framework that enables us to model a fungus’ individual competitive ability along a two-dimensional gradient of varying C and N concentrations. We validate this model using a simplified system of two isogenic strains of wild-type Saccharomyces cerevisiae yeast, and show that the outcomes of their competitive interactions are robustly predicted via the differences in their individual competitive abilities (in this case, growth rate) at each point along the environmental gradient. We further induce microevoluation in the yeast strains by growing them under various nutrient limitations for >240 generations; the model likewise predicts the competitive outcomes of these novel species interactions (among both ancestor and descendent populations) from their individual performances across the C and N gradients. These results show that the appropriate selection of the competitive trait (or “performance currency”; sensu McGill et al. 2006) along an environmental gradient can be used to predict a fungus’ realized niche ­­­– subject to competition – from the relative competitive abilities of each species in the community. This approach contrasts with traditional competition theory (i.e., the ability of a species to “draw down” the resource to a lower level than its competitor), and is more likely realistic for those fungi that compete for space or resources through direct combat.

1 - Yale University, School of Forestry and Environmental Studies, 370 Prospect St, New Haven, CT, 06511, USA
2 - University of Georgia, Odum School of Ecology, Athens, GA, 30602, USA

Keywords:
Competition
Realized niche
Fundamental niche
traits
R*
Microevolution
Saccharomyces cerevisiae.

Presentation Type: Offered Paper - Paper
Session: 1
Location: Room 103 AB/Kellogg Hotel and Conference Center
Date: Monday, June 9th, 2014
Time: 9:45 AM
Number: 1006
Abstract ID:29
Candidate for Awards:Graduate Student Oral Presentation Award