Quantifying Ecosystem Services Provided by Horticultural Production Landscapes in the Lake Chad Basin Region of North East Nigeria

Horticultural production landscapes in the Lake Chad Basin of North East Nigeria provide multiple ecosystem services beyond food and fiber, including water regulation, carbon sequestration, biodiversity support, and cultural services, yet these services remain unquantified in regional environmental accounting frameworks. As the Lake Chad Basin ecosystem faces accelerating degradation from climate change and land use pressures, understanding the full ecosystem service value of horticultural landscapes is critical for evidence-based conservation and investment planning. This dissertation applies an integrated ecosystem service assessment framework, combining the InVEST modeling suite with field-based biodiversity and soil carbon measurements, to quantify provisioning, regulating, supporting, and cultural ecosystem services in horticultural production landscapes of Borno and Yobe states. Ecosystem service trade-off and synergy analysis was performed across five contrasting land management scenarios using Bayesian network models. Stakeholder valuation of ecosystem services was assessed through choice experiments administered to 180 farming households and 40 policymakers. Results indicate that diversified horticultural polyculture systems deliver ecosystem service bundles worth 3.2 times the value estimated for monoculture vegetable systems, primarily driven by pollination support, soil carbon retention, and water infiltration regulation. The study establishes the first ecosystem service valuation baseline for North East Nigerian horticultural landscapes and argues for payment for ecosystem services programs targeting horticultural landscape managers in the Lake Chad Basin. Keywords: ecosystem services, horticultural landscapes, Lake Chad Basin, valuation, North East Nigeria