Soil and vegetation responses to hydrological manipulation in a partially drained polje fen in New Zealand

摘要: Anthropogenic drainage causes loss of natural character in herbaceous wetlands due to increased soil oxygen penetration. We related vegetation gradients a New Zealand polje fen long-term effects drains by using hydrological, edaphic and data, before-after-control-impact (BACI) design test responses experimental drain closure. Soil profiles continuous water level records revealed site subject frequent disturbance intense but brief floods, followed long drying periods during which areas close experienced lower tables more variable levels. Classification data identified 12 groups along moisture gradient, from dry dominated pastoral alien species, wet communities native wetland sedges. Lower total species diversity representation were the high proportion competitor competitor-disturbance compared with stress tolerator-dominated flora other groups. Species–environment relationships highly significant correlations content aeration as measured redox potential (EH) steel rod oxidation depth, well nutrient bulk density. Comparison root anatomy confirmed greater development flood-tolerant traits than aliens, N:P ratios indicated that most probably nitrogen-limited. Flooding rapidly re-established hydrology dried sites impact area, lowered EH had no effect on N P availability. Presence cover decreased these areas. This study supports use hydrological manipulation tool for reducing thus plant at restoration minimal intervention, suggests need detailed information flooding tolerances preferences underpin this approach.