Restoration of a calcareous river floodplain in southwestern Montana, part 2: presentation of monitoring data

Abstract

Active and passive restoration treatments were monitored for wetland vegetation recruitment on a large river floodplain in southwestern Montana. Species richness gains at the end of the monitoring periods were greatest in passively restored rich fen, extremely rich fen stream terraces, and alkaline meadows adjoining fens. Restored hydrology resulted in removal of exotics and natives intolerant of longer hydroperiods and recruitment of natives adapted to fully restored hydrology. Both active and passive treatments resulted in establishment of 5 rare species from borrowed sod, redistributed soils, and undisturbed in situ seedbanks. Seed characteristics and dormancy types can influence seed longevity in native wetland seedbanks, which can contain cryptic diversity in refugium populations of some rare species appearing after restoration treatments.