Biological Impacts
The biological components identified as being susceptible to the mine project are fish and fish habitat, wetlands, terrestrial ecosystems, vegetation and soils and wildlife and wildlife habitat.
Fish and fish habitat
Wetlands
Terrestrial Ecosystems, vegetation and soils
Wildlife and wildlife habitat
Fish and fish habitat
The mine project could potentially affect negatively local populations of several species of fish and their habitats. Before the establishment of the mine, Galore Creek valley was a pristine environment. A sampling program was done to identify the fish species present in the vicinity of the mine site, the filter plant and the aerodrome, along the access corridor and in the Stikine River. Streams, rivers, wetlands and lakes were surveyed and variable such as fish tissue metal concentration, diet composition, growth and health were also analysed. This background information will allow future comparison for follow-up and monitoring plans. Dolly Varden, rainbow trout, mountain whitefish, bull trout, coho salmon, sockeye salmon and Chinook salmon were the species the most often encountered, with the Dolly Varden being present in every area. The VECs identified for the fisheries in the mine project’s area are:
1) Dolly Varden: the most widespread species in the area, blue-listed in B.C. (list of any ecological community, and indigenous species and subspecies considered to be of special concern in B.C.)
2) Bull trout: blue-listed and globally threatened
3) Pacific salmon species: especially sockeye and coho salmon occurring in the Porcupine River
4) Other fish species (rainbow trout, mountain whitefish, longnose sucker, threespine stickleback)
5) Stikine River: culturally and economically valuable river supporting several populations of Pacific salmon, wildlife and human populations
The potential effects of the mine on productive capacity of habitats, habitat loss and alteration, direct and indirect mortality and sublethal effects were analysed in the mine area, the mill tailings and waste rock facility, the site runoff and diversion channel, the access corridor and pipelines zones, the Porcupine aerodrome area and the filter plant effluent. Overall, habitat loss, fuel and contaminant spills and acid rock drainage could have the most serious potential effects on the fish species.
Mitigation:
· Develop a fisheries management and fish habitat compensation plan in consultation with Fisheries and Oceans Canada, Tahltan Central Council and the Ministry of Environment
· Sediment and erosion control plan, site isolation during construction, settling ponds and diversion
· Water treatment facility
· Spill management plan
· Contained de-icing area at aerodrome
· All runoff will enter tailings impoundment
· Scheduled discharges at high flows with monitoring
· Where mitigation impossible, compensation plans will be developed to ensure no net loss of fish habitat
· Committed to aquatic effects monitoring and follow-up
Wetlands
Nine wetland regions have been identified around the project’s area. Wetlands have important ecosystem functions and many wetland-related policies and legislation exist. In the area, wetlands provide habitat for aquatic and terrestrial organisms such as algae, invertebrates, amphibians, fish and mammals. The assessment focused on the effects of wetland loss on fish, grizzly bear, moose and western toad, which are dependent on wetlands for all or part of their life cycle. Potential effects of the mining project on wetland area lost/altered, hydrological function, water quality function and carbon sequestration function of wetlands were analysed in the access corridor, the aerodrome and the mine areas.
Access corridor
Wetland Area lost/altered
- Loss of 4.4 ha of wetlands in this area
- 2 ha dominated by sedges (bear and western toad habitat)
- Crosses 2 wetland regions, may restrict wildlife movement
- Noise from corridor construction may reduce bear habitat value
- Fish habitat could degrade due to increased sediment and contaminant loads
Hydrological Function
- Presence of culverts will allow down-slope water flow
- This ensures integrity of upslope wetlands not compromised
- However, wetlands down-slope of the corridor exposed to different water flow patterns
- This will cause loss of some wetland areas and creation of new ones
- Net effect = loss of wetland has negligible effect on hydrological function
Water Quality Function
- Wetland dominated by sedges, so due to their high organic matter content, improve water quality by sorbing contaminants from the water as it percolates
- This type of wetland is common in the area, so no significant effect of wetland loss on water quality function in this area
Carbon Sequestration Function
- Less than 2 of the 4.4 ha lost in access corridor are peatlands (represents 1% of total peatland in area)
- Loss of these wetlands will have no significant effects
Aerodrome
Wetland Area lost/altered
- There are wetlands located close to proposed aerodrome site
- Have high grizzly bear and moose forage value
- Noise and other activities may reduce wildlife habitat function
- Biodiversity could be affected due to contamination from spills and sedimentation
Hydrological Function
- Flood control measures designed to protect the aerodrome could result in altered water flow downstream
- Reduce ability of wetlands to buffer against downstream flooding
Water Quality Function
- Wetlands downstream of aerodrome have abundant macrophyte cover: important for surface water quality
- Macrophytes slow water velocity allowing settling of sediments
- Altered upstream hydrology due to aerodrome could result in higher water levels and loss of macrophytes, which would decrease water quality function
- Altered upstream hydrology could create macrophyte habitat upstrem
- Decreased macrophytes downstream + increased macrophytes upstream = balance, so no significant effect on water quality function
Carbon Sequestration Function
- Wetlands downstream of aerodrome are marshes
- Marshes less valuable for carbon sequestration
- Loss of these wetlands will have no significant effects
Mine Area
Wetland Area lost/altered
- 7.9 ha lost and 6.7 ha altered within the mine site are dominated by grizzly and moose forage species, but high elevation makes low habitat value
- These wetlands represent 6.5% of total western toad reproduction habitat in area
- No significant effects
Hydrological Function
- Water retaining function of lost/altered wetlands in mine area will be offset by creation of open mine pits
Water Quality Function
- Water quality function of sediment deposition function of lost/altered wetlands will be offset by creation of mine pits (low flow will allow settling of particulates)
Carbon Sequestration Function
- Wetlands lost/altered are peatlands, but represent only 8% of the project area’s 193 ha of peatlands
- Lost peatland is estimated to store between 2.5 and 4.2 t of C per year (less than 0.00001% of B.C.’s annual C emissions)
In summary, the 12.3 hectares that will be lost due to development represent 4% of the total wetland (293 hectares) habitat within the mine project’s area. The project designers have made conscious efforts to adhere to the first step of the federal wetland mitigation process, which is wetland avoidance. The only significant consequence anticipated is the degredation of fish habitat in the More Creek habitat along the access road.
Mitigation
· Avoid wetlands where possible
· Transport concentrates and diesel with pipelines to reduce traffic and effects on wetlands
· Address compensation for loss of wetland function in the fish habitat compensation plan
· Deactivate corridor upon closure will allow safe movement of wildlife between wetlands
· Compensatory habitat creation
· Committed to monitoring and follow-up plans
Title.
Ecosystem mapping and field surveys were used to describe the terrestrial ecosystems, vegetation and soils of the mine project’s area. Rare communities and plants were identified by referring to the B.C. Conservation Data Centre and the Committee on the Status of Endangered Wildlife in Canada. This background information has been acquired for the regional project area, the filter plant and access corridor, the mine area and for the country foods present. The three main potential effects of the mine project on the terrestrial ecosystems, vegetation and soils are related to ecosystem alteration, effects on plant species of conservation concern and the potential introduction of invasive species. These three components were analysed for the filter plant and access corridor, the aerodrome, the mine area and the country foods. Direct impacts on the ecosystems, vegetation and soils are predicted to occur through alteration and disturbance during construction operations and decommissioning. Indirect impacts could include dust from pits and roads, microclimate changes and a decrease in ecological integrity through the potential introduction of invasive plant species.
Mitigation:
· Salvage and stockpile topsoil for use in reclamation and protect topsoil piles through revegetation
· Use adaptive management approaches to ensure advances in reclamation research are included in final closure planning efforts
· Conduct test plots during operations to support appropriate revegetation of reclaimed areas
· Reclaim using plants that will set stage for natural succession and the establishment of plant communities that reflect ecology of area
· Monitor, with Tahltan participation, surface water, soil and vegetation concentrations of selected metals throughout the period of mine development and operation. A quantitative screening level risk assessment (SLRA)for country foods will be conducted if the quality of these environmental media is shown to decrease and should a specific country food appear vulnerable, monitoring of contaminant levels in the tissues consumed, if feasible, will be undertaken
· Committed to monitoring and follow-up
Wildlife and wildlife habitat
The assessed wildlife valued ecosystem components included grizzly bear, mountain goat, moose, American marten, hoary marmot, bats, western toad, waterfowl, harlequin duck, raptors, songbirds and trumpeter swan. Species were selected if they met any of the following criteria:
• At risk or of conservation concern
• Highlighted in the Cassiar Iskut-Stikine Land and Resource Management Plan
• Government agencies asked for them to be considered
• Identified through Traditional Knowledge interviews with Tahltan Elders as being culturally and/or economically significant to the Tahltan Nation
For each of the species and groups identified as VECs, the potential effects of the mine was analysed on each of these components:
1) Terrestrial habitat loss
2) Wetland and river habitat loss
3) Disruption, blockage and impediments to movement
4) Sensory disturbance
5) Disturbance of feeding, breeding and denning habitats and behaviours
6) Features acting as attractants
7) Direct mortality
8) Indirect mortality
9) Reduction in wildlife productivity
Overall, the habitat loss, vehicle collisions, noise disturbance, increased contact with humans and chemical hazards are the events that will most likely affect wildlife. This is where the project proponents will concentrate their efforts to reduce the negative consequences. As an example of the detailed EIA analysis, a summary of the analysis of the potential effects on the grizzly bear is given here:
Grizzly Bear
Terrestrial Habitat Loss
- Loss of habitat at mine site, access road, filter plant, aerodrome and heliport
- Loss of habitat for both coastal and interior bear populations
- Loss of forage habitat likely to have greater impact on interior pop.
- Reclamation of disturbed habitats after closure, except pit and tailings, overall effect negligible
Wetland & River Habitat Loss
- 7.2% of wetlands supporting spring/summer forage will be lost
- This represents only 0.02% of total habitat available in project area
- Effects on grizzly bear considered negligible
Disruption, Blockage &Impediments to Movement
- Physical structures (open pits, diversion ditches, tailings impoundment) may affect movement of bears
- Large areas of continuous suitable habitat will remain, so alternative routes between habitats are accessible
- Traffic = 0.6 vehicles/hr, bears cross roads when <10 vehicles/hr
Sensory Disturbance
- Noise as highest disturbance potential in valley, where bear have summer habitat
- Uncertain whether bear will get use to noise, monitoring will be done
Disturbance of feeding, breeding & denning habitats/behaviours
- Activity/noise from aerodrome may disturb grizzly bear feeding activities during salmon spawning period
- Suitable denning habitats are at elevations above mine, unlikely disturbed
- Construction and operation could influence selection of denning areas over time, bears avoid human activity areas
Features acting as attractants
- Mine camps are in regions overlapping bear habitats
- Camps may attract bears, need management of camp/facility wastes
- Bears coming too often in camps will be relocated
Direct Mortality
- Bear-vehicle collisions
Indirect Mortality
- Increased hunting pressure (roads open, population more accessible)
Reduction in wildlife productivity
- Activity and noise in aerodrome area may disturb grizzly feeding, which could cause lower reproductive success, poorer physical conditions
- Could have considerable effects
Mitigation:
· Develop and implement a Wildlife Mitigation and Monitoring Plan
· Avoid some construction activities during sensitive periods for wildlife
· Maintain vegetation buffers around the project area to increase sound attenuation
· Record incidental observations of mountain goats during avalanche control procedures (survey flights) to increase knowledge of goats in relation to avalanche terrain
· Avoid nesting sites
· Report wildlife-vehicle and human-wildlife interactions and compile records to help identify any locations with high-levels of wildlife conflicts
· Many others
· Committed to a wildlife and wildlife habitat monitoring and follow-up program to support or verify the predications made on environmental effects
WRITTEN BY: MELANIE TRUESDELL
Last updated: April 16th, 2008
References:
NRSC 437 Lecture notes
http://www.eao.gov.bc.ca/epic/output/html/deploy/epic_document_239_23630.html
