Riparian floristic diversity and carbon stock assessment of an urban landscape: The case of Marjoya River in Batangas City, Philippines

Riparian floristic diversity and carbon stock assessment of an urban landscape: The case of Marjoya River in Batangas City, Philippines

Urban riparian forests remain understudied in the Philippines despite their importance in ecosystem services for anthropogenic landscapes, such as hosting the city’s local biodiversity and contributing to carbon capture and storage. However, human activities constantly threaten these ecosystems and remain poorly studied. This study assessed the riparian floristic diversity and carbon stock of mangrove forests in the Marjoya River and the Batangas City Mangrove Conservation Ecopark to establish baseline information and inform conservation recommendations. Using multiscale random plot sampling across four stations (upstream, midstream, downstream, and a mangrove eco-park), researchers documented 59 plant species from 52 genera and 27 families, including 33 native species (8 endemic) and 26 exotic species, with 4 locally threatened species identified. Biodiversity metrics indicate moderate species diversity, likely influenced by proximity to human disturbance and fragmented forest patches. Carbon stock was estimated at 33.657 Mg C ha-1 (~123.521 Mg CO2) in total, averaging 7.791 Mg C ha-1 (~28.594 Mg CO2 ha-1), which is substantially lower than national averages (~170 Mg C ha-1 or 623.9 Mg CO2 ha-1) and other local studies, although soil carbon data were not included. These results highlight the vulnerability of urban riparian forests to anthropogenic pressures and underscore the need for enhanced protection, conservation, and land use planning to sustain their ecological functions and carbon storage capacity amid ongoing urban development. The study contributes critical knowledge on urban mangrove ecosystems in the Philippines, emphasizing their role in biodiversity support and climate mitigation within anthropogenic landscapes.