Wetland ecosystems are vital for both biodiversity and communities that
depend on them. The Ligawasan Marsh in the Southern Philippines is one
of the most threatened wetlands in the country. Apart from growing
anthropogenic developments (e.g. natural gas extraction and
industrialisation), marshes face warfare-driven threats that have
hindered research and conservation efforts in the area for many decades.
Our study is the first to investigate the patterns of physicochemical
parameters, the impact of land-use changes on the environmental status
of the marshland, and the contribution of surrounding towns. We found a
strong negative correlation between dissolved oxygen (DO) and indicators
of pollution such as biochemical oxygen demand (BOD), chemical oxygen
demand (COD), and heavy metals. Interestingly, we observed elevated
levels of phosphate and mercury at all sampling sites within the
Ligawasan Marsh. Our landscape-level modelling showed that these
elevated levels are associated with expanding croplands and
urbanisation. Furthermore, we utilised our newly developed Marshland
Impact Area (MARia) Index. We found that the potential impact
contribution of cropland and urbanisation from surrounding towns of the
Ligawasan Marsh varied significantly, suggesting the importance of
implementing local policies to reduce land use change impacts. With the
current limited knowledge and beyond safe pollution levels in the
Ligawasan Marsh, it is crucial to implement collaborative and
science-based governance to integrate conservation initiatives with the
priorities of global targets, such as the Kunming-Montreal Global
Biodiversity Framework, for a comprehensive and sustainable approach to
Ligawasan Marsh conservation.