ABOVEGROUND NET PRIMARY PRODUCTION ALONG A BOG-FEN-MARSH GRADIENT IN SOUTHERN BOREAL ALBERTA, CANADA

Total aboveground plant production in a bog, three rich fens and two m arshes were determined via the multiple harvest and cranked wire techn iques. These peatlands follow a gradient of increasing pH, water flow, and surface water nutrient concentrations from the bog to the rich fi ns to the eutrophic marshes. The net primary production (NPP) values w ere as follows: (i) bog, 390 g m(-2) year(-1), (ii) three rich fens (r iverine sedge fen, lacustrine sedge fen, and floating sedge fen), 409 g m(-2) year(-1), 277 g m(-2) year(-1) and 356 g m(-2) year(-1), respe ctively, and (iii) one riverine and one lacustrine marsh, 323 g m(-2) year(-1) and 757 g m(-2) year(-1), respectively. Overall, the bog and the three fens had a similar NPP but they were significantly less prod uctive than the marshes. Along this bog-fen-marsh gradient, moss and s hrub production decreased and herb production increased. Herb and mass production exhibited a greater variation between years than among sit es within each year. Shrub production remained similar during both yea rs of this study. A significant tree stratum was only present in the b og. Generally, NPP was greater in 1994 than in 1993. Comparisons with other NPP data from bogs, fens, and marshes throughout North America s howed that the results. of this study complement a latitudinal gradien t of NPP for bogs. The latitudinal gradient for NPP in fens and marshe s is less pronounced.