Urban Green Space Analysis
Integrating Virtual Gaming Technology to Map Cultural use and Biodiversity Hotspots on The University of British Columbia Vancouver Campus
Introduction
Five major green space types were found in UBC Vancouver campus: 1) planting bed on structure, 2) planting bed, 3) urban Forest, 4) athletic field, 5) lawn
Urban Green Space
Rapid growth in urbanization has transformed natural landscapes into built environments due to human intervention. Consequently, the species' biodiversity is threatened, while the innate relationship between humans and nature begins to fade gradually. Urban green spaces play a vital role in reconnecting human and urbanized landscape with its unique characteristics. Urban green spaces act/serve as nature-based solutions in climate change adaptation, biodiversity, and air pollution, frequently discussed.
In addition to the ecological services that green spaces provide, they also enrich citizens' quality of life by providing social gatherings and recreational opportunities to facilitate natural environment experiences. Trees and understory vegetation in green spaces offer both tangible and intangible benefits to the local environment and visitors, and these values refer to ecosystem services. This framework introduces provisioning services, supportive services, regulating services, and cultural services.
Study Area: University of British Columbia Vancouver Campus
The University of British Columbia (UBC) was established in 1908, the oldest university in British Columbia. Vancouver is a well-known coastal city with its multiculturalism, and the UBC Vancouver campus is the home of 55990 students. UBC highly values staff and students' cultural diversity while maintaining its high academic reputation and achievement. According to the 2019 student enrollment statistic, Aboriginal students and international students make up to 30 percent of current UBC students. The concept of social inclusion and culture recognition is well demonstrated in UBC.
Since 1925, the UBC Campus and Community Planning department have worked with multiple disciplines to take proactive actions to steward green spaces in the UBC Vancouver campus. Approximately 8000 trees planted and over 10000 native trees in natural settings, where western redcedar (Thuja plicata), pin oak (Quercus palustris), and red maple (Acer rubrum) are dominant species on campus. The landscape management of green spaces also resonates with the city’s biodiversity strategy to support biodiversity and enhance the quality and access to nature.
Five green space type defined in the University of British Columbia Vancouver campus.
Methods
To understand users' perception of urban green space, remote sensing Light Detection and Ranging (LiDAR) technology, ground-based tree inventory, and reality gaming technology Pokemon GO was used to visualize cultural interests and vegetation biodiversity values at the UBC Vancouver campus. Three major steps were conducted for this purpose.
- Data Derivation and Validation
- Data Normalization
- Green Space Analysis
Data Derivation and Validation
Light detection and ranging (LiDAR) point cloud was computed into ArcGIS for data derivation. Once collected, the raw point cloud was classified and denoised. The Watershed segmentation method was applied to delineate the 2D individual tree crown in R with the ‘ForestTools’ package.
Ground-based tree inventory was represented in light green, which was measured by Urban Forestry Students in 2019 and collected by Amy Blood.
A total of 445 trees were manually identified and the centroids of the trees are located at the bottom of the tree to minimize the distortion effect of the aerial photo. As the tree centroids were defined, I created a tree crown based on the location of the centroid and the radius of the tree crowns.
Data Normalization
Species richness, canopy cover, native species ratio, and cultural features are four indicators to determine this project's green spaces’ biocultural values. Pokemon go is a very popular real-time virtual gaming app and it utilizes the GPS in our phones and produces geospatial coordinates with user-defined cultural interests
The data normalization process of four indicators was completed in ArcGIS Pro using different geoprocessing tools. The normalized data ranged from 0 t0 1, where 0 represented low, and 1 represented high.
Green Space Suitability Analysis
Once four indicators were normalized, I applied them into a weighted overlay analysis on ArcGIS Pro to explore the cultural interests and biodiversity values.
Assessment 1 included all four indicators and associated weight: species richness (0.2), canopy cover(0.2), native species ratio (0.15) and cultural point density(0.45).
- Assessment 2 included only two indicators with even weights: canopy cover(0.5), and cultural point density(0.5).
Result and Discussion
The map of a ranked cultural uses and biodiversity value green space over the UBC Vancouver campus.
Relationship between two assessments
Identified biocultural green spaces tended to become clustered at the northern part and the southern part of the study area, where these green space areas can offer social gatherings and events. The biocultural value of green spaces differs by considering different factors and weights. Since biocultural diversity was introduced to explain the interrelationships and interdependencies between people and their natural environment, we reckoned cultural interest and biological aspects for both biocultural green space assessments.
First assessment determined three major green space types, lawn, planting bed, and urban forest. The second assessment that covered a larger geographic area identified four green space types.
Two different assessments both highlighted the importance of urban green space type. This green space type achieved 0.396 in the first assessment and 0.501 for the second assessment of cultural and biodiversity values. This project provided a primary resource that emphasized the preservation of urban forests needs to be prioritized in future campus planning and development.
Future Work
LiDAR has shown strong potential in urban green spaces by producing individual tree crown delineation for canopy cover analysis and biomass estimation. With the combination of supplement ground inventory data, the green space biomass could be estimated. Many studies indicate the importance of vegetation biomass in the urban area. The higher the vegetation volume, the higher the sense of 'being away' from the urbanized areas. Moreover, the citizen science data offers great input in ecosystem service perceptions, and regularly integrating the remote data adds benefits in data collection.
