Assessment of Alien Plant Invasions and Management Responses in Nigeria’s National Parks: A Comparative Institutional Review

Alien plant invasions in Nigerian national parks are monitored and managed with varying levels of institutional commitment and professional capacity, and a comparative institutional review across the National Park Service estate provides essential evidence for policy improvement. This study assessed the alien plant invasion status and institutional management responses in four Nigerian national parks: Cross River National Park (South South/South East), Old Oyo National Park (South West), Kainji Lake National Park (North Central), and Chad Basin National Park (North East). Data were collected through institutional document review, structured interviews with park management staff (n = 48), field inventory surveys at two sites per park, and analysis of management action records for 2019 to 2023. Species invasion status was documented using a standardised alien species impact scoring system. A total of 37 alien plant species were recorded across the four parks, with 11 classified as having high ecological impact. Cross River National Park had the highest alien species richness (28 species), while Chad Basin National Park had the lowest (12 species). Institutional management capacity varied significantly: only Kainji Lake National Park had a dedicated alien species management strategy. Annual budget allocation to alien plant control averaged less than 3% of operational budgets across all parks. Manual removal was the only control method in use at three parks. The study recommends mandatory alien plant management plans, dedicated control budgets, and professional staff capacity building across the Nigerian National Park Service estate.

Keywords: alien plant invasion, national parks, institutional management, invasive species, Nigeria