River incision and vegetation dynamics in cut-off channels

摘要: The consequences of river incision on ecosystems dynamics in cut-off channels were hypothesized to be 1) the reduction backflows and overflows former channels; 2) seepage flows from drainage into 3) hillslope aquifer by channels. subsequent changes aquatic plant communities should terrestrialization higher part their change more oligotraphent ones if is poorer nutrients than river. In those reaches where bed aggraded, channel increase, as seepage, eutraphent species develop. Changes vegetation studied over a ten-year period four supplied nutrient-poor nutrient-rich Two them located an incised reach river, one aggraded (reference) that was neither nor incised. reference exhibited only minor period, indicating successional trend not perceptible at time scale study, thus any observed other can ascribed or aggradation. Terrestrialization expected clearly progressed downstream parts, but inhibited groundwater supplies upper parts. As expected, remained dominant part. highest floristic changes. this channel, unexpectedly, also upstream Alternative explanations are: aggradation could have instigated without modifying significantly mean water-level frequent water favoured alluvial deposition terrestrialization.