Influence of Fire and Disturbance-Altered Hydrology on the Abundance of Phragmites australis

AbstractHistorical land-use conversion and drainage may increase the risk of high intensity, soil-consuming fires in peatlands. Severe fires may degrade ecosystem resilience through changes in hydrology and by removing remnant seed and bud banks. Given this, peatlands are highly susceptible to species invasions from aggressive colonizing species post-disturbance. In this work we aimed to address the impacts of smoldering fires on the abundance of the noxiousPhragmites australisin a large fire scar at the Great Dismal Swamp National Wildlife Refuge (VA and NC, USA). Primarily, we wanted to observe the extent of the relationship between the altered hydrology of post-fire conditions andP. australisoccurrence. We did so by leveraging high resolution satellite imagery, random forest models, LiDAR data, and water table observations. Our results suggest thatP. australisis aided by a hydrologic regime generated, in part, from the combined effects of drainage and deep smoldering fires. Our findings emphasize the importance of hydrologic management post-disturbance for limitingP. australisinvasion. Further, we highlight the potential for feedbacks between deep peat consuming burns andP. australisinvasions and spread in degraded peatlands.