Temporal patterns in recruitment from the seed bank during drawdowns in a prairie wetland

  • Published source details Welling C.H., Pederson R.L. & Van der Valk A.G. (1988) Temporal patterns in recruitment from the seed bank during drawdowns in a prairie wetland. Journal of Applied Ecology, 25, 999-1007.


This study is summarised as evidence for the following.

Action Category

Actively manage water level: brackish/salt marshes

Action Link
Marsh and Swamp Conservation
  1. Actively manage water level: brackish/salt marshes

    A replicated study in 1981–1984 of 10 adjacent brackish marshes in Manitoba, Canada (Welling et al. 1988) reported that seedlings germinated during two summers of drawdown following prolonged deep flooding, with most seedlings of dominant perennials germinating in the first summer. The study reported seedling numbers for seven herbaceous emergent species. For four perennial, grass-like species that dominated the marshes before intervention, 120–49,000 seedlings/100 m2 germinated in the first summer of drawdown (vs 160–3,400 seedlings/100 m2 in the second). For three annual forbs, 2,300–31,000 seedlings/100 m2 germinated in the first summer of drawdown (vs 85,000–200,000 seedlings/100 m2 in the second). Methods: The water level in 10 slightly brackish (2–3 ppt) diked marshes on the shores of Lake Manitoba was actively managed: deep flooding for two years (water level raised 1 m above normal, killing most emergent vegetation) followed by drawdown in spring 1983 or 1984 (water level dropped to 20 cm below normal). This mimicked historical water level fluctuations in Lake Manitoba. Seedlings were counted monthly in summer 1983 and 1984 in up to twenty 1-m2 quadrats/marsh. Quadrats were placed in the zone around the historical shoreline where emergent vegetation had been killed during flooding. This study was based on the same experimental set-up as (1).

    (Summarised by: Nigel Taylor)

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