Early stages of decay of Lythrum salicaria L. and Typha latifolia L. in a standing-dead position

Lythrum salicaria (purple loosestrife) has invaded wetlands across North America and is known to have negative effects on native plant species and diversity. The effects of this invasion on ecosystem processes are less well known. We examined decomposition of L. salicaria stems versus that of native Typha latifolia (broad-leaved cattail) in a previously cultivated, freshwater marsh in central New York State. We expected different decomposition rates and differences in litter quality of L. salicaria stems and T latifolia shoots. We also quantified ergosterol concentration, an index of fungal biomass. However, standing-dead T latifolia shoots and L. salicaria stems had lost similar quantities of mass (20-25%) after 1 year. Subsequent heavy snowfall and winter winds caused tissue fragmentation and much greater mass loss, but still similar for both plant species. Ergosterol concentrations were greater in T latifolia shoots than in L salicaria stems; yet, changes in tissue concentrations of nitrogen (N) and Klason lignin were very similar for both plant species. Therefore, although native T latifolia may be more favorable in wetlands, the results of this study suggest that L. salicaria stems and T latifolia shoots decompose in a similar fashion and have similar influence on the ecosystem-level processes measured in this study. (C) 2002 Elsevier Science B.V. All rights reserved.