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Monday, April 9 • 5:30pm - 7:00pm
POSTER: North American and Asian Cities Show Contrasting Trends in Urban Greenspace Over Recent Decades

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AUTHORS: Jiali Jin*, Research Institute of Forestry & Laboratory of Tree Breeding and Cultivation, State Forestry Administration & Urban Forest Research Centre, State Forestry Administration, Chinese Academy of Forestry; Sarah E. Gergel, Landscape Ecology Lab, Department of Forest and Conservation Science, Faculty of Forestry, University of British Columbia; Yuhao Lu, Integrated Remote Sensing Studio, Department of Forest Resources Management, Faculty of Forestry, University of British Columbia; Nicholas C. Coops, Integrated Remote Sensing Studio, Department of Forest Resources Management, Faculty of Forestry, University of British Columbia; Cheng Wang, Research Institute of Forestry & Laboratory of Tree Breeding and Cultivation, State Forestry Administration & Urban Forest Research Centre, State Forestry Administration, Chinese Academy of Forestry

ABSTRACT: Urbanization is responsible for vegetation loss and landscape fragmentation impacting ecological processes, ecosystem services and human health. As such, urban greenspace which provides significant environmental benefits, is critical for both residents and wildlife in urban areas. Pan-Pacific cities are the fastest urbanizing centres in the world and home to nearly 55% of the global urban population. However, a lack of cross-site comparison limits our understanding of changing greenspace in such cities. To investigate changes in greenspace heterogeneity, we built annual Landsat composites from 1984 to 2012 for 16 cities across seven countries in the pan-Pacific region to answer two primary questions: 1) Do trends in greenspace heterogeneity change over time?; 2) How does greenspace heterogeneity vary along urban gradients? Normalized difference vegetation indices (NDVI) were used to distinguish four classes of greenspace using a thresholding technique. Landscape metrics including Edge Density (ED) and Percentage of Landscape (PLAND) were used to characterize the greenspace attributes. Temporal dynamics of greenspace were assessed using the Mann-Kendall test. Applied generalized additive mixed models (GAMM) helped describe the change trajectory of ED and PLAND and evaluate differences among “greening” and “browning” cities. Gradient analysis of spatial patterns along all radial directions from city centres was used to detect directional changes in greenspace. We also used Principle components analysis (PCA) to find the metrics most useful in comparing the differences between Asian and North American cities. Our results suggest that more than half of pan-Pacific cities became greener as they became wealthier. In contrast to browning cities, most greening cities showed increases in dense vegetation along the urban gradient. Compared to North American cities, dense vegetation in Asian cities increased and became less fragmented. These comparisons can be used to guide future planning for green infrastructure at regional scales.

Monday April 9, 2018 5:30pm - 7:00pm CDT
Monroe Room

Attendees (6)