Positive feedback favors invasion by a submersed freshwater plant.

摘要: The submersed macrophyte Utricularia inflata has invaded lakes in northern New York State, thereby threatening native isoetids such as Eriocaulon aquaticum. Isoetids often dominate and modify softwater due to their capacity oxidize sediment thus influence solute mobilization. Greenhouse experiments tested the hypotheses that U. invasion could result higher porewater iron (Fe) concentrations greater ammonium (NH4+) Fe release from into water column, this mobilization would stimulate further growth. In first experiment, three levels of impact on E. aquaticum were imposed using cores overlain by lake water: alone, with a cover inflata, bare sediment—the latter simulate local extirpation isoetid invasive. After 16 weeks, NH4+ total dissolved significantly (P < 0.05) for treatments. Water column these solutes five-fold treatment than indicating can compromise quality. A second experiment demonstrated grew faster over 0.05), likely absence Where causes decline Adirondack Mountain lakes, changes chemistry create positive feedback loop escalating invasive species.