Coastal wetlands are naturally resilient to changing sea levels; however, as rates of sea-level rise increase, the interaction between changing sea-level and ongoing human impacts will be a major driver in future coastal tidal marsh stability. My goal is to provide decision makers with recommendations to increase the resilience of the Fraser River delta front tidal marsh communities over the twenty-first century. I conducted a literature review to (1) examine the current knowledge base regarding effects of sea-level rise on tidal marshes and (2) identify current ecosystem-based adaptation strategies for increasing tidal marsh resilience to sea-level rise. Based on this review, recommendations are made for strategies that could be used to increase tidal marsh resilience in the Fraser River delta. Recommendations include (1) initiating delta-wide marsh accretion modeling to assess tidal marsh vulnerability under possible sea-level rise scenarios and (2) implementing sediment augmentation pilot projects for both direct (e.g., layered sediment lifts) and indirect (e.g., mud motor) sediment augmentation strategies to test ecosystem based adaptive management strategies as part of an adaptive management framework.
This study began to investigate potential facilitative effects among shrub species in riparian ecosystems in southwestern British Columbia. I ran two concurrent studies. Six plots for each of four treatments were established at the Coquitlam River Wildlife Management Area. The first two treatments compared the survival, growth, flowering, and herbivory rates of planted twinberry seedlings in plots where the shrub layer was removed to plots where it was not. The other two treatments compared the survival, growth, leaf loss, flowering and herbivory rates of snowberry plants in plots where the salmonberry upper shrub layer was removed to those where it was not. No significant differences between the measured parameters in any of the treatments were found. These results are discussed in the context of the riparian forest ecosystem and current facilitation theory. The results are then used to inform an ecological restoration plan for the Suwa’lkh School Forest., Facilitation, Riparian forests, Native vegetation, Symphoricarpos albus, Lonicera involucrate, Rubus spectabilis, Ecological restoration
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 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 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
Large woody debris removal has been ongoing in the Fraser River Delta since the late 1800’s. I investigated how offshore winds and the absence of large wood may have contributed to the recession of the Sturgeon Bank Marsh. I suggest large wood increases marshland resilience and promotes new marsh establishment by attenuating wave energy, decreasing sediment mobilization, deterring herbivory, and promoting the establishment of vegetated islands from which the marsh can expand. I analyzed historical wind data for patterns in offshore wind duration and installed several pieces of large wood onto the tidal flats of the Sturgeon Bank. I developed a technique for anchoring wood in the intertidal and give my recommendations for further development. Finally, I conclude the recession of the Sturgeon Bank Marsh was the result of multiple interacting stressors and coin the term keystone structural element to describe the function of large wood within a foreshore marsh., large woody debris, keystone structural element, marsh recession, ecological restoration, wave sheltering, coastal marsh
Relationships between changing environmental variables and amphibian populations have been understudied. Yet, alterations to temperature and precipitation have been suggested as contributors to the decline of some pond-breeding species, such as the Oregon Spotted Frog (Rana pretiosa). R. pretiosa has been classified as the most endangered amphibian in Canada, yet the cause for its decline is unknown. Therefore, this paper examined associations between temperature and precipitation, and R. pretiosa population trends, using a 10-year data set from two breeding populations in the
Lower Mainland of British Columbia. Timing of oviposition was positively related to higher temperature and increased precipitation within both populations (p<0.05). No statistical relationship was determined between egg mass productivity and temperature or precipitation; however, this paper proposes that further research, consistent protocols and longer study periods, is necessary in order to determine environmental variables as possible predictors of population success. This paper recommends the evaluation of breeding success through survivorship studies, as such methods provide insight into
productivity as the primary determinant for population recruitment. Further, ecological restoration efforts can be implemented to help ameliorate negative consequences climate change poses on reproductive success., amphibian, climate change, conservation, ecological restoration, endangered, population dynamics, population monitoring, survivorship