Temporal Dynamics and Time Series Analysis of Mangrove Ecosystems and Community Impacts in Bayelsa State, Nigeria: An Assessment of Environmental Change and Conservation Implications

Abstract

Mangroves found in Bayelsa State, Nigeria, are critical coastal environments currently facing intense pressures from activities including oil exploration, land use change, and effects of global climatic change. This study aims to analyze the attributes of the mangroves between 1990 and 2023 using secondary databases to capture changes and map major drivers of environmental degradation. Environmental data from different governmental databases were analysed using R language. Time series analysis, trend profiling and multivariate statistical modelling were utilized to analyze mangrove coverages, changes in species population and the driving environmental factors. The results show a significant loss of 29.7% of mangrove covers within the 33-year study window, equivalent to a total reduction of 293.2 km² from 987.4 km² in 1990 to 694.2 km² in 2023, with a long-term average annual loss rate of 1.05%/year across the full study period (1990–2023), accelerating to approximately 2.1% per biennial reporting cycle during the 2010–2020 sub-period of heightened industrial activity. Rhizophora racemosa was most sensitive to environmental stresses, and Avicennia germinans showed a critical decline of 47.8% in its population. In addition, heavy metal contaminations emerged as a major threat, and 78% of the monitored stations exceeded WHO guideline levels, especially with a whopping rise of 268.5% in the levels of lead. The study also captured 1,247 oil spill incidents and registered a peak occurrence of oil spills from 2008 to 2012. The study concludes that, unless immediate conservation measures are taken, Bayelsa State is likely to lose an additional 15-25% of what remained of mangrove area by 2035. This investigation offers vital baseline information critical to the development of informed conservation planning and places significant focus on the urgent imperative of integrated management plans within the Niger Delta wetlands.