Ecological Impacts of Anthropogenic Activities on Biodiversity and Ecosystem Functioning in Changing Climates

Abstract

This study assessed the impacts of anthropogenic activities and climate change on biodiversity and ecosystem functioning in the Cross River National Park and its surrounding landscapes in southeastern Nigeria over a 23-year period (2000–2023). Using a combination of satellite remote sensing, field biodiversity assessments, and climatic data analysis, the study quantified trends in land-use transformation, species richness, and environmental variables. Results indicated a significant reduction in forest cover from 12,000 hectares in 2000 to 6,200 hectares in 2023, corresponding to a 48.3% loss. Concurrently, agricultural land expanded from 2,800 hectares to 7,500 hectares (a 167.9% increase), and urban areas grew by 140.7%, from 1,200 hectares to 2,890 hectares. Biodiversity indices showed a marked decline, with the Shannon-Wiener index decreasing from 3.82 in 2000 to 2.41 in 2023, indicating substantial species loss and ecosystem simplification. Climate data revealed a rise in mean annual temperature from 26.1°C to 28.3°C and a decline in annual rainfall from 2,100 mm to 1,800 mm during the study period. Pearson correlation analysis showed strong negative correlations between forest cover and biodiversity index (r = –0.83, p < 0.01) and between temperature increase and species richness (r = –0.76, p < 0.05). Multivariate regression analysis confirmed that 78.5% of the variability in biodiversity loss could be attributed to land-use change and climate variability (R² = 0.785). These findings underscore the synergistic impacts of human development and climate change on tropical ecosystems and highlight the need for integrated conservation and climate adaptation strategies. Recommendations include reforestation, sustainable land-use planning, and the incorporation of climate-smart policies to preserve the ecological integrity of the park.