Urbanization-induced impacts on mangroves at multiple scales
Ms WEI Shan PhD Student, Department of Geography, HKU
Mangroves are trees and shrubs that grow in coastal intertidal zones of tropical and subtropical regions. Mangroves cover only 0.1% of land surface but provide valuable ecosystem services that are beneficial to environment and humanity. Mangroves are efficient carbon sinks and hotspots of biodiversity, serving a critical role in coastal protection and climate change mitigation. Unfortunately, being significant to coastal sustainability, mangroves forests have decreased at a worrying rate over the past decades, under various pressures from both natural and anthropogenic forces. Numerous studies have proved that mangrove loss was mainly caused by proximate drivers, including land use replacement, coastal development, overexploitation, and pollutions. Particularly, urbanization has been widely recognized as an important factor for the dramatic mangrove loss due to the conversion from mangrove to urban land or infrastructures. Many cities have experienced rapid urbanization accompanied by environmental problems and human disturbances, particularly in coastal zones, which revealed negative impacts towards mangrove loss in previous literature. However, urbanization was directly represented by spatial expansion of urban land, without considering other perspectives, such as population, economic and social developments that are caused by urbanization. There was also a lack of consideration of the impacts of distal factors (population dynamic, accessibility, socioeconomic development, tourism, conservation strategy and non-local impacts, etc.) driven by urbanization. In recent decades, conservation efforts on mangrove restoration have achieved great successes, which is also attributed to the increasing awareness of environmental protection during urbanization process. So, the interaction and relationship between mangrove and urbanization is highly complex and challenging to be fully understood to balance the environmental and urbanization considerations. To this end, this thesis aims to 1) identify the temporal and spatial pattern of mangrove distribution and landscape fragility during the past few decades at different geographic scales; 2) understand the interaction between urbanization-driven drivers and mangrove ecosystem; and 3) qualify the urbanization-induced impacts on mangroves during different periods at different scales. Preliminary results indicated that China’s urbanization has complicated relationship and impacts with mangrove forests in China during different periods, and the government’s conservation policy demonstrated significant impacts on the relationship. These preliminary results indicate the interesting and underexplored urban and mangrove relationships at different space and time scales.