PARENT SESSION
Poster Session # 10: Soil Ecology.
Tuesday, August 5 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Root foraging strategies of herbaceous plants: Trade-offs and size-dependence.
Rajaniemi, Tara*,1, 1 Indiana University, Bloomington, IN
ABSTRACT- Plants may use various strategies to forage for spatially heterogeneous soil resources, including high scale foraging (exploring maximum soil volume), high precision foraging (concentrating root growth in resource-rich patches), and high rate foraging (reaching and/or depleting resource-rich patches quickly). Differences in foraging strategies might increase or decrease coexistence. Trade-offs among foraging traits may allow competing species to coexist. In contrast, if larger individuals forage more precisely or at a higher rate, those individuals might pre-empt resource patches, contributing to size asymmetric competition belowground. Size asymmetry is expected to increase competitive exclusion. I used a greenhouse experiment to measure the scale, precision, and rate of root foraging in eight herbaceous species over a range of individual sizes. No trade-offs among the species were detected: the species with the greatest scale of foraging also had the greatest precision and reached patches most quickly. Precision and rate of foraging were size-dependent for some species: in two species (Bromus inermis and Festuca rubra) larger individuals foraged more precisely; in three species (B. inermis, Achillea millefolium, and Centaurea maculosa) larger individuals reached patches more quickly; and in two species (B. inermis and C. maculosa) larger individuals had greater root growth rates within patches.
Key words: root growth, plant foraging, soil heterogeneity