CARBON CYCLE LEGACIES OF TIE DRIVING IN ROCKY MOUNTAIN HEADWATER STREAMS, WYOMING USA

Fluvial systems are linked to the global carbon cycle through processes related to storage, transport and their importance in dictating biogeochemical conditions of stream ecosystems. Previous research has demonstrated strong relationships between stream geomorphology and ecosystem processes such as stream metabolism, but little is known about how past stream channel disturbances influence these relationships or how streams recover from these historic disturbances. This research uses the context of a legacy disturbance (tie driving) to expand on the functional interactions between geomorphic controls and riparian variables in regulating three key aspects of carbon dynamics: allochthonous inputs and storage, decomposition, and ecosystem metabolism. Results of this research indicate that contemporary channel storage capacity and riparian composition reflect disturbance legacies and create different carbon cycling contexts. Differences in carbon pools between disturbance and reference conditions are evident in terms of both quantity as well as lability (availability). Carbon fluxes, as measured through ecosystem respiration and decomposition, are also linked to differences in channel dynamics and riparian condition related to disturbance legacies. Findings of this research contribute to the current understanding of feedbacks between stream channels and ecosystem function at contemporary time scales.