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Invasive Species Removal and Restoration at Viaduct Flats hand in water' The Veins of Life
Watershed Society

Email: volws@salishsea.ca


 
Background

The Viaduct Flats are located south of  the lands of the Horticultural Centre of the Pacific in Saanich, B.C. They have been drained and used for agricultural land for many years. The farming, mostly potatoe, that took place on this piece of land was eventually abandoned. Shortly after the flats were left to fill naturally, sightings of a beaver were reported which built a dam to further fill the flats. 

Beaver dams create habitat that is ideal for nesting waterfowl and songbirds and it was not too long before this area began to be regularly used by Canadian geese, Mallards and many others. A survey was done in 1993 by the Victoria Natural History Society, which catalogued the variety of species now using the area (Figure 1).  The Viaduct Flats are now one of the most prolific wetland areas for migratory waterfowel on the entire Island.  The land has a covenant placed on it and the Horticultural Center of the Pacific has become the official steward.

The area surrounding the flats was logged prior to the creation of the Horticultural Centre. Most recently, the Horticultural Centre applied for and received funding from Forest Renewal British Columbia to restore these forests. The Coastal Douglas Fir forest type is considered threatened and therefore it is important to maintain the remaining parcels. Maintaining these parcels involves first undergoing invasive species removal and then reintroducing native plants found in a Coastal Douglas Fir forest.
 

Figure 1. Viaduct Flats Pond and resident waterfowl 


Veins of Life Watershed Society Involvement

Along the edges of the forest and altered creek path invasive species such as Himalayan Blackberry (Rubus discolor), Scottish Broom (Cytisus scoparius) and Reed Canary Grass (Phalaris arundinacea) have grown into a dense thicket of vegetation. However, Himalayan Blackberry makes up the bulk of the thicket (Figure 2.)


Figure 2. Beginning of Himalayan blackberry thicket bashing 

Veins of Life has been involved in many projects of invasive species removal and native species reintroduction (see Gorse Removal in Gorge Park). With this experience Veins of Life was ready and willing to take on this immense task of removing all the Blackberry to expose the topography and plant native species.

 The society  will also be responsible for the contruction of trails that will surround the pond and cut through the forest, a platform and boardwalk for viewing, and signage to educate the public on the project as well as the natural history of the area. 

Phases of Viaduct Flats Project

Phase One : Invasive Species Removal

 The singular most important tool in combating a thicket of blackberry is a pair of loppers (Figure 3.). Loppers are used to cut the blackberry in large sections and then once brought to ground level cut into smaller pieces which can be easily be walked over (Figure 4). Occasionally, a brush cutter is used to take out some of the smaller sections of blackberry and canary grass. All cuttings remain on the ground to maintain the biomass of the area. Removing too much biomass makes it difficult for the native vegetation to establish.
 
 

Figure 3. Best weapon against blackberry invasion 
Figure  4. Blackberry cut into small pieces making it easier for replanting

Phase Two: Native Species Reintroduction

After a corridor is cut through the blackberries along the fence and the base of the slope of the property then a planting grid of 4 m will be established. 28 species, including 11 tree sprecies, totalling 3,350 plants will be planted on the 4 m centres and interplanted with Sitka alder (See complete species list).  When canopy closure has been achieved the Sitka alder will be removed. Suppression of the blackberry will continue until canopy closure has been achieved. Roundup cannot be used in the covenant area or within 10 m of the creek.
 
 

Figure 5. Planting of native species at Viaduct Flats

 

Progress

 Both Fall 2000 Veins of Life Crews participated in the invasive species removal and revegetation with native ones. The contract for these two steps goes until MR.h 2001. All the invasive species removal and native species reintroduction may not be completed by the time the next crews begin in January 2001. From there the next crews will carry on and may be involved in the further steps of the project. Information on those future steps will be updated as the project proceeds.
 
 

© 2009 Veins of Life Watershed Society / All Rights Reserved / if you wish to use any info for commercial or non commercial usage you must obtain permissions from The Veins of Life Watershed Society

Email: volws@salishsea.ca