I want to understand how differential responses among plant and mycorrhizal fungal species to global change impact plant-plant, plant-fungal, fungal-fungal relationships and the feedbacks of these relationships into their broader (a)biotic environment. As part of my research, I have variously worked in ecosystem-scale manipulations (current postdoc, masters), radiolabeling experiments in microcosms (PhD), and observationally along environmental gradients (masters, technician) in a variety of biomes. While my experiences applying different approaches to similar problems have humbled my expectations in the ability to comprehend such an unwieldy topic scientifically, these experiences have not discouraged me from trying.
I am attending this conference to build strong friendships with other plant scientists with differing perspectives on plants, ecosystems, ecology and the ecological role of humanity.
Boreal plant roots do not grow deeper to take advantage of depressed water tables
S. E. WEBER, J. CHILDS, J. LATIMER, G. SCHWANER, C.M. IVERSEN
Climate Change Science Institute, Environmental Sciences Division, Oak Ridge National Laboratory 1 Bethel Valley Road, Oak Ridge, TN 37830 USA
Boreal bogs host large stores of terrestrial carbon as peat. Long-term stability of peat is threatened by global change via altered rhizosphere conditions, temperatures, and hydrology. High water tables, cold temperatures and low pH in bogs favors Sphagnum moss production over vascular plant functional types (PFTs): trees, shrubs and sedges. We hypothesize that warming will increase the growth of vascular plant roots, particularly in deeper peat as water tables sink. Additionally, we hypothesize elevated [CO2] to amplify root productivity responses to warming, by inducing greater plant nutrient demand via CO2 fertilization. We tested these hypotheses in the SPRUCE experiment, a whole-ecosystem warming gradient (+0 to +9 °C in 2.5°C steps) ✕ ambient and elevated (500 ppm) [CO2] manipulation. Manual minirhizotron images from 2015-2021 were used to estimate root production and depth for each PFT. Root production by ericaceous shrubs increased with warming under elevated, but not ambient [CO2]. Rather than being more deeply distributed under warming & elevated [CO2], this root production was either more shallowly distributed or remained at the same depth. Altogether these results suggest that vascular plants in boreal bogs will respond to global change through shallow root production, possibly to capture nutrients from recent litter inputs.