Ecosystem Services of Aquatic Spawning and Nesting Habitats Across Semi‐Sahel Alkalinization Stress and Regime of Nakambé River

ABSTRACT The preservation of spawning and nesting aquatic habitats is essential for the survival of species inhabiting Bagré Aquatic Perimeter (BAP). Our approach includes a comprehensive inventory of climate regime impacts on the spatio‐temporal distribution and the integrity of fish spawning habitats for the long‐term durability of BAP aquatic systems. Geospatial data and alkalinization variation coefficients were used to define transects across BAP. Technical data on nesting habitats conservation were collected using direct field observations, interview surveys and focus groups with fishers across BAP transects. We found water temperature, early seasonal rainfall, early cessation of seasonal rainfall and high levels of sunshine to be the main factors influencing seasonal nesting sites ( p ‐value < 0.001). The nesting sites of fish communities are mainly located along the BAP shorelines. The spawning periods depend on alkalinization gradients and vary according to annual climatic conditions. Fishers coping strategies for adapting to climate regime vary significantly from one alkalinization gradient to another ( p ‐value < 0.001). The ecosystem services provided by BAP nesting sites are under climatic influences, as well. The types of spawning substrates for fish nesting are fine sand, clay, rocks, cage‐like nests, grasses and sometimes the undersides of inert wood. A part from the inert woods, all the other substrates types varied significantly over BAP transects ( p ‐value < 0.001). Fish migrate during the spawning season in groups, pairs, and often in distinct shoals. The primary causes of post‐spawning larvae mortalities are related to cannibalism, predation, herbicides and cyanide. Fish mating behaviour in natural aquatic environments involves courtship displays in the water column. Artificial spawning habitats and egg‐hatching facilities along the alkalinization gradient of the BAP appears to be essential for better environmental restoration of aquatic nesting sites.