PARENT SESSION
Contributed Oral Session 15: Populations and Genetics: Succession; Reproduction
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 522 A, Level 5, Palais des congrès de Montréal
Plant phenotypic plasticity belowground: A meta-analysis of root foraging tradeoffs.
Kembel, Steven*,1, Cahill, James1, 1 University of Alberta, Edmonton, Alberta, Canada
ABSTRACT- Many plants are able to proliferate roots in nutrient-rich soil patches, presumably increasing nutrient uptake and plant fitness. Soil nutrient heterogeneity has been thought to help maintain plant community diversity due to a hypothesized tradeoff between the spatial extent over which plant species forage (foraging scale) and their ability to proliferate roots precisely in nutrient patches (foraging precision). Empirical support for the foraging scale-precision tradeoff hypothesis has been mixed, with some authors suggesting that interspecific differences in relative growth rate may be confounded with measurements of foraging precision. We collected previously published data from numerous studies of root foraging ability (foraging precision, foraging scale, plant growth response to soil heterogeneity, and relative growth rate) and phylogenetic relationships for more than 100 plant species in order to test these hypotheses using comparative methods. Root foraging precision was broadly phylogenetically and taxonomically conserved in seed plants. Using both ahistorical and phylogenetically independent contrast correlations, we found no evidence of a root foraging scale-precision tradeoff, mixed support for a relative growth rate-foraging precision relationship, and no support for the widespread assumption that foraging precision increases the benefit gained from growth in heterogeneous soil. Based on these results, we suggest that tradeoffs between foraging scale and precision are not widespread in seed plants and cannot explain patterns of plant community diversity, and that our understanding of the impacts of plant foraging precision and soil heterogeneity on individual plants and plant communities are less advanced than commonly believed.
Key words: root foraging, scale-precision tradeoff, phenotypic plasticity, comparative methods