OIDA International Journal of Sustainable Development
Open-access peer-reviewed journal
https://doi.org/10.64211/oidaijsd190407
An Integrated Geospatial Assessment to Evaluate Factors Affecting Sustainability of Ecosystem Services of Urban Wetlands Due to Fragmentation: A Case study of Bellanwila-Attidiya Wetland in Sri Lanka
H.K.U. Dewmini 1*, H.M.B.S. Herath 2
1 Department of Geography, Faculty of Humanities and Social Sciences, University of Sri Jayewardenepura, Sri Lanka.
2 Department of Geography and International Center for Multidisciplinary Studies, Faculty of Humanities and Social Sciences, University of Sri Jayewardenepura, Sri Lanka.
*Corresponding authour: udaradewmini@sjp.ac.lk
Abstract: Urban wetlands are crucial ecosystems that offer a wide range of ecosystem services, including flood mitigation, biodiversity support, and climate regulation. However, in rapidly urbanizing areas, the sustainability of these services is increasingly compromised by land fragmentation. The objective of this research was to identify ecosystems services provide by the Bellanwila-Attidiya Wetland and to analyse spatial and temporal changes of wetland fragmentation and to evaluate the drivers of loss of ecosystem services provided by the Bellanwila-Attidiya Wetland due to wetland fragmentation. A geospatial assessment was carried out using Landsat satellite images acquired in 1995, 2011 and 2024 to assess spatial and temporal changes of fragmentation. Fragmentation parameters such as the Number of Patches, Patch Density, Mean Patch Area, and Edge Density were estimated using QGIS to assess wetland fragmentation that affects the sustainability of ecosystem services. Then factors affecting the loss of ecosystem services due to fragmentation was assessed. The data were collected through key informant interviews with experts and focus group discussions with local residents of the wetland. The results indicated that the Bellanwila-Attidiya Wetland provides vital ecosystem services including flood regulation, biodiversity conservation, water purification, air pollution control recreational opportunities and health benefits for residents and people living in surrounding region. Spatial analysis from 1995 to 2024 reveals a significant reduction in wetland cover from 60% to 38% accompanied by increased fragmentation, with the number of wetland patches rising from 16 in 1995 to 141 in 2024. Household surveys and interviews revealed that unregulated housing expansion (70%), inadequate enforcement of environmental laws (68%), and infrastructure development (65%) as the primary factors of wetland fragmentation that have affected the sustainability of ecosystem services in Bellanwila-Attidiya Wetland. The survey data revealed that 67% of respondents have observed a noticeable decline in water quality over the past decade. Biodiversity indicators, including bird and amphibian presence, were reported to have decreased by 45% since 2000, based on observational and community-reported data. The findings of the research highlight the need for stronger conservation efforts. Implementing clear land-use policies, restoration programs, and better enforcement can be recommended to sustain the Bellanwila-Attidiya Wetland’s ecosystem services.
Keywords: Ecosystem services, Environmental sustainability, Fragmentation, Geospatial analysis, Urban wetlands
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