Changes in a wetland plant association induced by impoundment and draining

摘要: Abstract In 1977 a newly constructed gravel access road blocked water flow across shrub swamp in Tewksbury, Massachusetts, draining one section and impounding another. Within year, the vegetation drained area shifted substantially toward denser more species-rich association. After three years changes slowed, but they had not stopped after six. Many of these would be expected to reverse themselves once normal flooding pattern was established. flooded there little for first years, that time many species began decline numbers, with most pronounced effect occurring five years. Even short-term alterations cycle can have substantial long-lasting effects on wetland vegetation.