Net above-ground primary production along a bog-rich fen gradient in central Alberta, Canada

The above-ground net primary production (NPP) and litter fall of five peatlands (bog, poor fen, wooded moderate-rich fen, lacustrine sedge fen, and extreme-rich fen) representing the bog-rich fen gradient in central Alberta, Canada were measured during two growing seasons. Total above-ground NPP increased along the gradient from the bog to moderate-rich fen and then decreased in the sedge and extreme-rich fens. Above-ground NPP in the bog (264-297 g . m(-2). yr(-1)) was low compared to other North American bogs, while the Alberta fens had intermediate values of NPP (214-360 g . m(-2). yr(-1)) compared to other North American fens. Moss NPP was lowest in the sedge fen but did not differ significantly between the other peatlands. Vascular plant NPP was highest in the poor fen, moderate-rich fen, and sedge fen and lowest in the bog and extreme-rich fen. Herb NPP tended to increase along the bog-rich fen gradient, while shrub NPP tended to decrease along the gradient. Litter fall was greatest in the poor and moderate-rich fens and lowest in the sedge and extreme-rich fens.