부산대학교 도서관

Fire is a critical driver of plant and soil nutrient cycling in nutrient-limited ecosystems. Phosphorus (P)-limited and fire-adapted ecosystems can uptake fire-released P, but it is uncertain how post-fire hydrology interacts with fire severity to affect carbon (C) and P cycling in plants and soils. We examined the interactive effects of fire severity and post-fire hydroperiod (defined as the number of days of surface soil inundation in a year for which maximum water depth is a proxy) on soil and plant C and P cycling in intermittent wetlands in south-central Florida. We burned eight wetlands (maximum water depth 0–60 cm), maintaining replicates of four unburned wetlands (maximum water depth 0–48 cm) for reference. We collected surface water, plant and soil chemistries, plant species composition, and % cover during pre- and post-fire periods and measured hydroperiod in all wetlands post-fire. Fire severity—measured as the relative amount of vegetation consumed—was higher in shallower, shorter-hydroperiod wetlands than in deeper, longer-hydroperiod wetlands. Surface water total and dissolved C and nutrient concentrations declined following experimental burns and likely interacted with post-burn flooding. Pre-fire, we detected higher soil C concentrations in longer- than shorter-hydroperiod wetlands; however, soil P was similar among wetlands despite differences in soil C concentrations. Post-fire, soil C and P concentrations were higher in longer-hydroperiod, burned wetlands compared to unburned and shorter-hydroperiod, burned wetlands. Pre- and post-fire plant C and P concentrations were higher than soil C and P concentrations, and post-fire plant C and P were similar among all wetlands regardless of experimental burn treatment. Post-fire plant cover varied with hydroperiod and was largely unaffected by fire, and cover of mineral soil (that is, sand) increased by 6–14 times and bare organic soil increased by 5–30 times post-fire in longer-hydroperiod wetlands. Our results demonstrate that fire severity and post-fire hydrology drive the amount of nutrient release and the extent of post-fire plant succession in nutrient-poor, intermittent wetlands. The impacts of fire on ecosystem recovery are linked to nutrient and water availability. [ABSTRACT FROM AUTHOR]