Production and decomposition of vegetation along a wetland gradient in central Alberta

The net primary production (NPP), decomposition, changes in C and N and peat accumulation potential of the above ground vegetation of different peatlands representing the bog-rich fen gradient in central Alberta, Canada were measured during two growing seasons (1991 and 1992). The wetland gradient studied was: (1) bog (2) poor fen (3) open moderate (4) rich fen (5) wooded moderate-rich fen (6) sedge fen (7) extreme-rich fen.; Total above ground NPP increased along the gradient from the bog to wooded moderate-rich fen and then abruptly decreased in the sedge and extreme-rich fens. Average above ground production in the bog was lower than values from more southerly North American ombrotrophic systems. The Alberta fens had intermediate values of NPP compared to other North American minerotrophic peatlands.; Moss production did not differ significantly between most of the sites and showed greater variation between years. Vascular production and litter fall were highest in the middle of the bog-rich fen gradient.; Weight loss of the dominant species at the sites was negatively correlated with initial and final C:N ratios and positively correlated with initial and final %N. After one year, weight loss of the standard litter (Carex lasiocarpa), used for a cross site comparison, was negatively correlated with water level and pH-related parameters and positively correlated with surface water concentrations of TDP. The sites ranked: poor fen {dollar}>{dollar} wooded-rich fen {dollar}>{dollar} bog {dollar}>{dollar} open-rich fen {dollar}>{dollar} sedge fen, in order of greatest to least percent weight loss of the standard after two years. (Abstract shortened by UMI).