Response of montane meadow vegetation after two years of streamflow augmentation

Changes in montane meadow vegetation were examined in a previously ephemeral drainage that received flow augmentation as a mitigation measure for a transbasin diversion in southeastern Wyoming. After two years of elevated surface and groundwater levels, the herbaceous vegetation shifted toward more water-tolerant species. Dry meadows became like moist meadows, moist meadows became more like moist-wet meadows, and moist-wet meadows became more like wet meadows. Sedge (Carex spp.) biomass increased from 337 to 456 g m^?2 in the wet meadows, while tufted hairgrass (Deschampsia cespitosa) biomass decreased from 18 to 3 g m^?2 in the moist-wet meadows. Slimstem reedgrass (Calamagrostis neglecta) remained unchanged in the meadows with shallow standing water, but increased from 17 to 88 stems m^?2 in the dry meadows with an elevated water table. Bare ground also increased as much as 31 per cent in the meadows without a defined drainage channel.     

云雾苔草与蜈蚣草联合修复重金属污染土壤初探

由采矿、冶炼、加工及废弃物处置等造成的重金属污染土壤问题日益严重,环境污染影响越显突出。围绕云雾苔草与蜈蚣草超富集植物间种对重金属污染土壤联合修复的运用与实践进行试验探索。结果表明,分别采用云雾苔草、蜈蚣草和两者间种联合修复重金属污染土壤,铅、锌、铜、镉、砷等重金属含量均呈逐年下降趋势,间种方式的修复效果明显优于单独种植的效果。采用云雾苔草和蜈蚣草间种方式联合修复重金属土壤,对污染土壤的重金属修复效果持续有效,土壤中铅、锌、铜、镉、砷的浓度可降低至12.54mg/kg、40.21mg/kg、11.23mg/kg、0.06mg/kg和0.32mg/kg。