Invasive Plant Species and Microbial Processes in a Tidal Freshwater Marsh
1999
Otto, Sibylle | Groffman, Peter M. | Findlay, Stuart E. G. | Arreola, Anna E.
Vegetation has a strong influence on N retention in wetlands via direct uptake and by indirect effects on microbial N uptake and denitrificafion. Vegetation change in freshwater tidal marshes is dynamic due to both natural and anthropogenic factors and these changes may influence the water quality maintenance value (i.e., the ability to absorb exogenous N) of these marshes. We measured sediment microbial biomass and activity and plant N content and height in stands of Lythrum salicaria (L.), Phragmites australis [(Cav.) Trin. Ex Steud], and Typha angustifolia (L.) in 1995 and 1996 in Tivoli North Bay, a tidal freshwater marsh along the Hudson River in Dutchess County, New York. Lythrum and Phragmites are invasive plants that have displaced Typha in significant areas of this marsh over the past few decades. A fertilizer (two 5 g N m⁻² additions of urea) response study was conducted in 1996. There were few differences in microbial biomass and activity and response to N addition between the different plants despite marked differences in plant biomass and N content and significant annual variation in several variables. Although plant change has been dramatic in this marsh, and the new plants appear to cycle N differently than the native plant, microbially-based water quality functions may not have been affected by this change.
显示更多 [+] 显示较少 [-]