Reinforcing West African Slender-Snouted Crocodile populations: The potential contribution of captive-breeding and species distribution modelling

The West African slender-snouted crocodile (Mecistops cataphractus) is one of the world’s most threatened crocodilians, now listed as Critically Endangered and persisting only in fragmented West African river systems. Despite its severe decline, ecological knowledge remains sparse and consistent conservation planning is hindered by data deficiency, uncertain population structure, and limited habitat assessments. This thesis evaluates how ex situ captive breeding and Species Distribution Modelling (SDM) could jointly contribute to population reinforcement and reintroduction planning for M. cataphractus, providing a framework that bridges genetic evidence with habitat suitability mapping.
Mitochondrial DNA was sequenced from individuals held within the emergent European captive population to assess species identity, infer maternal relationships, and examine genetic suitability for future management actions. Phylogenetic reconstruction confirmed the placement of captive individuals within M. cataphractus, forming a well-supported clade sister to Osteolaemus. These results support the genetic validity of the current founder stock and highlight considerations for maintaining diversity within the breeding programme.
In parallel, a MaxEnt SDM was developed using presence-only occurrence records and climatic variables to estimate current habitat suitability across Africa, and projected under four CMIP6 climate scenarios (SSP126, SSP245, SSP370, SSP585) for 2021–2040, 2041–2060, and 2061–2080. Models revealed a concentrated suitability band across humid West African basins, with future projections indicating consistent range contractions of ~5–10%, particularly under low-emission pathways. Basin-level analyses identify priority regions for surveys and potential future reinforcement, with several areas remaining suitable under climate change.
By integrating genetic findings with spatial modelling outputs, this thesis demonstrates the potential for combining ex situ assurance populations with evidence-based habitat identification to support long-term recovery planning for M. cataphractus. The framework provides actionable guidance for conservation practitioners and establishes a foundation for future reintroduction and habitat-focused management.