Forest managers are interested in determining how stands that have been logged might be managed to restore features characteristic of forests in later-stages of development. Incorporating forest restoration into forest management enables the use of forest-management skills, such as silviculture and regeneration techniques, to manage individual stands for multiple objectives. Therefore, I performed a comparative analysis of large trees, very-large trees, large snags, very-large snags, and large CWD among three stand types (i.e., 60-yr-managed, 140-yr-natural, and 500-yr-natural stands). The 140-yr-natural and 500-yr-natural stands were used as reference conditions to guide the restoration of a 59-yr-managed spacing trial. All attributes differed among stand-types; however, large snags were the most similar attribute between 140-yr-natural and 500-yr-natural stands. Large trees were the fastest attribute to recover in 60-yr-managed stands, however mean values among stand-types still differed. This study highlights the potential of restoring old-natural attributes in younger-managed stands to increase ecological resiliency., forest, natural, managed, prescription, restoration, old-natural attributes
Over the past half century, urbanization has caused drastic changes to the hydrology and geomorphology of streams and rivers. The Serpentine River is a low-elevation, rain-dominant river located in the City of Surrey, British Columbia. Over the years, urbanization of the watershed, particularly in the upper reaches, has degraded what once was high quality spawning habitat for five salmonid species. The current project is an evaluation of previous restoration efforts at seven study sites and a restoration plan to effectively increase spawning habitat in the Upper Serpentine River. Grain size analysis of the study sites found up to 57% fine sediment in the subsurface particles, attributing to siltation rates of 1.2-1.6 kg/m2/day. Erodible grain sizes at the study sites ranged from 29-164 mm, which mostly exceeded the median size of spawning gravel. These results were verified with a tracer rock study, which together concluded that instream structures were required to reduce tractive forces and increase gravel retention.
Newbury weirs, or constructed riffles, were proposed as treatments because their hydraulic characteristics increase flow resistance, promote gravel retention, and create intergravel flows. Newbury weirs involve large diameter rocks spanning across the entire stream, causing accumulation of gravel on the upstream side and pool formation downstream side. Substrate scoured at the pool will be deposited at the tail end of the pool, creating spawning habitat in accelerating and downwelling waters. Bank stabilization using dense live staking with a protective rock toe key was prescribed to reduce further channel incision and siltation. In the longterm, watershed-level priorities including passage through the Serpentine sea dam, monitoring for urban contaminants, and installation of green infrastructure was recommended.
The proposed treatments are relatively inexpensive, and if successful, will reduce repeat addition of spawning gravel and increase salmonid production in the Serpentine River. However, the value of the current project extends beyond fish productivity estimates. Monitoring data from restoration works can be used to inform future urban stream restoration projects and contribute to the continual improvement of restoration techniques. The effects of restoration on not only sediment form (ie. gravel depth and size) but also processes (ie. sediment scour and fill) should be investigated in the field to verify theoretical models.
The Nicomekl River flows through historic Katzie First Nation territory in Surrey, British Columbia. The river provides salmon the linkage between their upland spawning and rearing grounds and the Pacific Ocean where they mature. Anthropogenic development has reduced habitat connectivity along the river, denuded the banks of vegetation, removed instream complexity, constrained the channel, regulated flow, and altered the water chemistry. A tidally controlled 7-gate sea dam is the source of the critical connectivity bottleneck on the river. It impairs free longitudinal migrations of adult and juvenile salmonids and increases adult and juvenile predation. Through literature review and site assessment, this study suggests a suite of restoration treatments to restore connectivity and site-based habitat attributes to the Nicomekl River. The study then considers management options in light of climate change, sea level rise, and how to generate public involvement to support the proposed treatments. The study concludes that urban stream restoration faces challenges as it must find a balance between the environmental and social needs of the Nicomekl River beyond simply repairing ecosystem damage and degradation., riparian restoration, salmonids, migration bottlenecks: connectivity
The coastal saltmarsh that once made up Lost Lagoon was isolated into a freshwater impoundment to enable the construction of the Stanley Park Causeway in 1916. Water chemistry, water nutrients, and subsurface sediment were collected in August to October 2017, and it was concluded that Lost Lagoon is experiencing, low DO (average 6 mg/L), high salinity (0.9 ppt), high nutrient loading (TP 0.1 mg/L and TN 0.9 mg/L) and has elevated heavy metals (Cd, Cu, Ni, Pb, and Zn). A general biotic inventory was conducted and results indicated a lack of native species diversity and presence of invasive species, for both flora and fauna. Projected future conditions concluded that Lost Lagoon is prone to stratification and higher temperatures, which is expected to further water impairment including, increases in NH3 and toxic algae blooms. To mitigate this trajectory, a systematic restoration plan was developed to reintroduce tidal flushing into Lost Lagoon from Coal Harbour’s western basin, thereby restoring the degraded ecosystem into a diverse coastal saltmarsh. Hydrogemorphology and flow rates were estimated and as a result a 1.3-m wide water channel was recommended. A planting and long-term monitoring plan that will aid in revitalization of a coastal saltmarsh was developed, alongside a preliminary project budget and schedule. The project feasibility and public response were discussed as constraints, with emphasis on furthering this proposed restoration plan with professional engineering, and First Nations and public consultation., ecological projections, restoration, urban wetland, saltmarsh, intertidal ecosystems
Urbanization of areas alters the natural hydrology of the land through the creation of impervious surfaces, removal of vegetation, and construction of storm sewer systems. These alterations impact physical processes and the biological communities of our waterways through the introduction of pollutants, creation of uncharacteristic hydrological regimes, and habitat loss and fragmentation. Integration of natural areas in our built environments will mitigate some of these effects and reduce the degradation of streams in urbanized watersheds.
Guichon Creek flows through an urbanized environment, which includes the British Columbia Institute of Technology (BCIT) Burnaby campus. A tributary flows into Guichon Creek at the south end of campus and the majority of its flow is from a stormwater sewer which receives runoff from the residential area east of campus. The tributary is approximately 150 metres and runs between a community garden and a small gravel parking lot before entering Guichon Creek.
This project proposes restoration of a 2,000 m2 parcel of land between Guichon Creek and the tributary. Restoration activities involve removal of an existing parking lot, management of invasive hybrid Japanese knotweed (Fallopia x bohemica) and Himalayan blackberry (Rubus armeniacus), creation of an off channel wetland, and addition of natural in-stream structures to the tributary. Wetlands provide important hydrological and ecological functions that will contribute to the restoration efforts on Guichon Creek. This wetland will improve hydrological functions of the Guichon Creek floodplain through increased groundwater infiltration, creation of a storage area, and pollutant filtration. Improving these functions is also an important component of making stream ecosystems more resilient to climate change. The wetland will also provide ecological benefits such as improved water quality and creation of amphibian habitat. This project focuses on the creation of habitat for northern red-legged frog (Rana aurora) and the Pacific chorus frog (Psuedacris regilla).
Another important component of restoration in an urban environment is creating a connection between people and the environment. Restoration of this space provides opportunities for public involvement and environmental education and awareness. This creates a forum to discuss the effects of urbanization on streams and show people where the runoff from their neighbourhood ends up. Forming that connection between people and their environment is an important step to creating interest and involvement in environmental issues.
Urbanization has altered riparian ecosystems, resulting in the decline of species that depend on them. The Brunette River in the Lower Mainland of British Columbia is no exception; though it currently supports a range of biotas, many of them are at-risk. These impacts are further accentuated by the expansion of the Trans Mountain Pipeline, which will result in the removal of a portion of critical habitat for the endangered Nooksack Dace. In light of the cultural significance of the basin to Kwikwetlem First Nations, the goal of this plan is to improve conditions at the project site post-construction through the establishment of culturally and ecologically important species and the addition of habitat features. I completed soil, vegetation, and water quality surveys to inform my prescriptions. Recommendations include the management of non-native species using manual and mechanical control methods and the planting of a native riparian community that fits within the confines of human infrastructure. A robust monitoring plan is also provided., critical habitat, exotic species, First Nations, restoration, riparian, urbanization
Forestry practices are thought to be the major cause of degraded salmonid habitat and declining steelhead populations in the Oktwanch River on Vancouver Island. Large woody debris installations and channel modifications were completed in Reach 1 of the Oktwanch River and adjacent side channels in 2001 to provide spawning and rearing habitat for multiple salmonid species and prevent further degradation, but were ultimately unsuccessful. This study investigated if watershed-scale restoration, rather than reach-scale, is necessary to restore this habitat for steelhead in the Oktwanch River indefinitely. This was achieved through an assessment of fish habitat in Reach 1 of the Oktwanch River and adjacent side channels and spatial analysis of the Oktwanch watershed using Landsat historical aerial imagery and i-Tree Canopy. The findings from this study suggest watershed-scale changes to forestry practices are required to restore steelhead populations in the Oktwanch River., forestry practices, watershed-scale restoration, reach-scale, woody debris installations, channel modifications
In agricultural landscapes, hedgerows provide critical habitat for songbirds. Himalayan Blackberry (Rubus armeniacus; HBB) is a widespread invasive species in the Pacific Northwest that has been linked to lower breeding songbird diversity. My study explored two possible explanatory mechanisms: educed structural complexity and lower arthropod abundance as a food source. I conducted avian point counts in 51 hedgerow segments at two locations in the Lower Mainland of British Columbia. In these segments, I quantified vegetation structure using a Foliage Height Diversity (FHD) metric derived from LiDAR data. I sampled arthropod abundance on the foliage of woody understory vegetation. I used multiple regression to identify best fit generalized linear models. Songbird diversity decreased with HBB % cover and increased with FHD. However, arthropod abundance was unrelated to bird metrics, and similar between HBB and other native shrubs. This suggests that hedgerows should be managed to control HBB and maximize vegetation structure., songbird diversity, agricultural landscapes, Himalayan Blackberry, hedgerows, arthropods, LiDAR
Old field is a unnatural habitat that usually occurs as a result of agricultural land abandonment and is the product of early-stage natural succession on a previously managed field. In an agricultural setting with monoculture crops, old fields provide more vegetative complexity through ground cover diversity and shrubs and hedgerows. In Delta, British Columbia, several old-field sites are managed for wildlife and provide nesting habitat for songbirds over the summer, as well as foraging habitat for overwintering raptors during fall and winter months. I surveyed two old-field sites near Boundary Bay, and two field sites at the Vancouver Landfill to compare the influence of old-field vegetation on different bird communities and improve understanding on species using the landfill. I conducted fixed-radius point counts for songbirds, and standing counts for raptors. Comparing replicate field types (n=2) I found that overall diversity of songbirds was higher in old field, and also associated with structural features like shrubs and trees, while abundances of Savannah Sparrows (Passerculus sandwichensis) decreased with proximity to shrubs and trees. My results support the conclusion that installing structural vegetation features at the landfill would maximize breeding songbird diversity. I also found the landfill to support higher diversity of wintering raptor species, but old field supported consistently higher abundances. This suggests that the landfill is currently functioning as lower quality wintering habitat, and that different management techniques should be considered.