Atlas of Bank Restoration Sites of the St. Lawrence River - Methodology
This atlas was produced over a four-year period, from 2003 to 2006, in several steps:
The first year of the project was devoted mainly to identifying partners, defining objectives, defining the study area, targeting the problems associated with restoration and evaluating the costs of producing the atlas.
During the last three years, the restoration problems selected during the first year were grouped under different themes. For each theme, a list of documents and organizations was consulted to better target possible sites for intervention. The database was complemented by field reconnaissance visits, usually conducted by car, but occasionally by boat for less-accessible environments. These field visits not only enabled new sites to be identified, they also served to better document those that already appeared in our database. In general, the following information was collected during a field visit: the georeferenced location of the site, accessibility, type of habitats disturbed, type of disturbances, surface areas to be restored (if possible), favored restoration approaches and expected environmental gains. Topometric measurements sometimes also proved necessary to better target the intervention site, or to better assess the surface areas to be restored. At each site, photographs were taken. The information thus collected was used to prepare development plans adapted to each of our projects. More precisely, the search for sites under each theme was conducted as follows:
- Improving access to flooded plains for fishes
- Dismantling of embankments
- Stabilization of eroding banks
- Recuperation of diked spartina marshes
- Setting up sills on drainage canals drying out spartina marshes
- Creation of openings within emergent freshwater marshes too densely colonized
- Restoration of existing man-made ponds for waterfowl
- Eelgrass plantation
- Planting in terrestrial habitat
- Controlling of invasive plant species in wetlands
Improving access to flooded plains for fishes (installation of culverts, reshaping of banks, removal of sediments within some watercourses…)
An initial list of structures that modify the water flow and likely harm fish was drawn up by photo-interpreting 1:15 000 aerial black-and-white photographs of island habitats in the Montreal–Berthier-Sorel Archipelago section of the St. Lawrence River. Subsequent field visits allowed us to validate the information, identify the best restoration approach and assess the anticipated environmental gains. Additional sites beyond those found on islands in the freshwater stretch of the St. Lawrence were identified in consultation with provincial and federal biologists in different administrative regions.
Dismantling of embankments
The database of sites with embankments was compiled through field research and by consulting with organizations that had worked in the St. Lawrence and had, over the years, identified places where unused or unusable structures could be removed. These embankments were then visited in the field so that their main elements could be described and to ensure that their demolition would not engender environmental impacts. The environmental gains expected following the removal of an embankment from a particular riparian zone were briefly assessed on site and following a literature review.
Stabilization of eroding banks
The work of Argus Environmental Consultants Inc. (1996a) was used to assess the extent and distribution of erosion in the Cornwall–Montmagny section. Work done by the Canadian Wildlife Service (Dauphin and Lehoux 2004) served as a reference document for precisely locating the banks of biological interest of the Lake Saint-Louis–Lake Saint-Pierre section that remain severely eroded, and for identifying the habitats as well as the main biological components threatened by this erosion. The document produced by Écogénie (2003a) was used to identify the best intervention measures for stabilizing the eroded banks of this section with the help of ecoengineering techniques. Eroding sites identified in the estuary were listed with the help of the document produced by Écogénie (2003b) and through consultations with provincial biologists. Field visits served to delimit sites, define the best stabilization approach and assess the impacts of this erosion on the natural environment (Écogénie 2005).
Recuperation of diked spartina marshes
Diked marshes not already converted into agricultural lands were listed with the help of a document produced by Argus Environmental Consultants Inc. (1998). A videotape on the shores of the middle and maritime estuary, produced in 1998, was also viewed in an attempt to find the exact location of diked marshes. Possible restoration techniques for reclaiming these marshes were inspired by those proposed by Argus Environmental Consultants Inc. (1998) and complemented by the fieldwork of Ducks Unlimited Canada. Through fieldwork, the desired interventions were located more precisely. Finally, a meeting was held with each aboiteau owner to assess their interest in future restoration of the diked marshes on their property.
Setting up sills on drainage canals drying out spartina marshes
Drainage canals that originate in agricultural lands in the high marsh area and dry out cordgrass marshes in the St. Lawrence estuary were located using a document produced by Argus Environmental Consultants Inc. (1998). A videotape covering the shores of the middle and maritime estuary, produced in 1998, was also viewed in order to locate the canals more precisely and to determine the possible impacts of their presence. Restoration techniques that could be employed to minimize the impacts were found in the document produced by Argus Environmental Consultants Inc. (1998). Projects conducted in cordgrass marshes by Ducks Unlimited Canada were also used to better explain the restoration method. Finally, site visits allowed the desired interventions to be targeted more precisely, particularly the location of retaining dikes that ensure that water remains in drainage canals, even during low tides. Finally, a property-title search was conducted.
Creation of openings within emergent freshwater marshes too densely colonized
In the present atlas, almost all of the sites with marshes occupied by dense emergent plants were proposed by the conservation group Ducks Unlimited Canada. Most of these sites are located in the Lake Saint-François floodplain. The preferred restoration approach consists of creating channels of open-water through the extensive cover of dense emergent plants composed mainly of cattails and shrubby willows. These openings are connected to the nearby watercourse in such a way that fish can access the interior of the development. In the early 1980s, Ducks Unlimited Canada carried out some developments of this type in the Lake Saint-François region (André Michaud, Ducks Unlimited Canada, personal communication).
Restoration of existing man-made ponds for waterfowl
The search for poorly planned artificial ponds was conducted entirely by patrolling the area by car. We concentrated our efforts on riparian environments adjoining freshwater and estuarine portions of the St. Lawrence River. Developments needed to improve ponds, particularly with the help of promontories or small islands, were inspired by work undertaken at the Cap Tourmente National Wildlife Area (S. Turgeon, CWS., personal communication) Environmental gains anticipated following restoration were determined through a brief literature review.
Work conducted by Lemieux and Lalumière (1995) was consulted to locate possible sites in the maritime estuary where Eelgrass might be established. The guide produced by Lalumière and Lemieux (1993) was used to define the methodology for creating new Eelgrass beds. The success of past transplantations in the estuary was assessed through field visits, and the key parameters guaranteeing the most successful transplantations were identified (Lemieux 2004). Additional visits further confirmed the establishment potential of Eelgrass in certain other target areas by ensuring that these areas had the hydrodynamic conditions and substratum previously defined as conducive to the establishment of the species, and to properly delimit the surface areas and the potential donor banks.
Planting in terrestrial habitat (Planting in rip-rap shores; Planting in disturbed dunes; Planting of trees and shrubs in anthropic green spaces; Planting of trees and shrubs in agricultural lands)
Many human activities can alter terrestrial vegetation. Nevertheless, within the Restoration Atlas our focus was on documenting the location of quays; marinas; certain rip-rap shores located in public places; riverside parks or wayside rest areas with poor tree and shrub growth; certain agricultural fields, particularly those on islands in the Montreal–Berthier-Sorel Archipelago section, or along the river or estuary; and finally, certain dune environments with vegetation damaged or destroyed by all-terrain vehicles and repeated stomping by visitors. Sites were usually identified through field visits or by consulting organizations knowledgeable about a given environment and its problem. In the particular case of agricultural fields on islands, we consulted 1:15 000 black-and-white aerial photographs of the area, as well as 1:20 000 wetland maps obtained using airborne MEIS-II images acquired in 2000 and produced by the St. Lawrence Centre (Guy Létourneau, SLC, unpublished data). Next, validation visits and meetings with farmers confirmed their interest in introducing windbreaks and better defined the development concepts particular to each site. Ideas for re-vegetating all listed sites, as well as the gains expected following their restoration, were determined by consulting experts in the field and by drawing from existing documents (Marie-Victorin 1964; Kress 1985; Hightshoe 1988; Paysage Nature 1988; Argus Environmental Consultants Inc. 1994; Choinière and Bélanger 1996; St Georges and Venne-Forcione 1999; Robert 2000; Attention FragÎles 2004).
Controlling of invasive plant species in wetlands
Wetland mapping at a 1 : 20 000 scale, produced by the St. Lawrence Centre (Létourneau and Jean, in prep.) with images acquired in 2000 and 2002, helped to locate the main colonies of invasive plants (Common Reed, Purple Loosestrife, Reed Phalaris) in the Cornwall–L’Isle-Verte section. An aerial survey of these invasive species, conducted in 1997 between Montreal and the Saint-François River by Gratton (1998), was also consulted. Finally, techniques for controlling these species were inspired by work conducted on the St. Lawrence River and in other parts of the world.
Assessment of the expected benefits of site restoration
Inventories of bird and plant species were conducted on certain sites. Where a systematic on-site inventory was lacking, bibliographic research allowed us to document the value of undamaged or undisturbed sites comparable to those we wanted to restore. This information led to an assessment of the environmental gains expected from restoration, whether for birds or aquatic wildlife or simply for biodiversity. With these censuses, we were also able to ensure that the sites to restore had not, over the years, become important habitats for species at risk, despite their degradation, and where it would then be inappropriate to intervene.
Data compilation and analysis
Finally, data collected from the three field campaigns, as well as the information derived from the literature, resource persons and organizations were analysed and compiled. The sites selected were located on a Google Earth map. Explanations of the problematic impact and the characteristics of each study site, diagrams describing the recommended restoration as well as a description of the environmental gains expected from restoring the analysed site, are provided. In order to better direct the organizations interested in conducting a restoration project, we also prioritized restoration sites according to the anticipated environmental gains under each given theme.