Recovery potential of the vegetation following destructive foraging.
At some inter-tidal sites, where the swards have been destroyed and the soil is hypersaline, it has taken more than 10 years for Puccinellia to begin to reestablish (the species does not set seed). This project will involve the establishment of replicated exclosures at sites along the coastline which represents a continuum of severity of degradation of salt marsh swards. The frequency of different plant species in permanent quadrats both within the exclosures and in adjacent plots will be monitored over 5 years. In highly damaged swards, changes in the species composition over this period are likely to be substantial once exclosures are erected.
In related restoration ecology projects, revegetation trials were conducted whereby soil plugs of Puccinellia phryganodes and Carex subspathacea from intact saltmarsh swards were transplanted into plots in degraded sites devoid of vegetation. Five replicated treatments were examined: a nitrogen-phosphorus fertilizer addition, a peat mulch addition, a combined addition of mulch and fertilizer, no addition of supplements and no addition of plugs or supplements. Growth of plants in the combined treatment is the most successful to date, based on one season’s growth. Shoot systems (stolons) of Puccinellia are spreading out from the plugs. In contrast, in bare plots with no addition of supplements, the shoot systems of Puccinellia or Carex are moribund or dormant. As well, planting trials in moss carpets (formerly sedge meadows) were conducted with Carex aquatilis. To date, no treatment effect (presence or absence of fertilizer) has been observed. These latter projects are the work of Tanya Handa. [email protected].
- revised 10/11/97 -