Development of a Novel Framework for Assessing the Cumulative Environmental Carrying Capacity of Nigerian Port Ecosystems

Environmental carrying capacity, the ability of an ecosystem to absorb anthropogenic pressures without experiencing irreversible ecological degradation, provides a theoretically robust basis for setting limits on port-related maritime activities. This study develops a novel environmental carrying capacity assessment framework specifically designed for the complex port ecosystem environments characteristic of Nigerian coastal ports, integrating marine engineering, environmental science, and ecological economics perspectives. The research employs an interdisciplinary methodology combining primary ecological data collection at three Nigerian port environments (Lagos, Port Harcourt, and Calabar), thermodynamic ecosystem modelling using the Ecopath with Ecosim software platform, cumulative impact assessment using multiple stressor additive and synergistic models, and economic valuation of ecosystem services using the benefit transfer approach. The novel framework makes three original theoretical contributions: first, the application of network analysis to characterise ecological connectivity between port and adjacent non-port ecosystems as a determinant of recovery capacity; second, the integration of climate change trajectory modelling as a background stressor that modifies carrying capacity thresholds over time; and third, the development of a maritime activity permit allocation algorithm that distributes allowable impact budgets among competing port users. The framework is presented as a decision support tool for port environmental management and is evaluated through scenario analysis of proposed port expansion at all three study sites. Keywords: environmental carrying capacity, port ecosystems, cumulative impact assessment, ecological modelling, Nigerian ports