Feeding ecology of the endangered Draa trout (Salmo multipunctatus) in contrasting karst headwater streams: insights into habitat quality

Land-use change in Mediterranean mountain regions has profoundly altered riparian habitats and stream ecosystems, threatening freshwater biodiversity. We investigated the feeding ecology of the critically endangered Draa trout (Salmo multipunctatus) in two contrasting karst headwaters of the Upper Draa basin, High Atlas, Morocco, to assess how riparian condition influences dietary composition and inform conservation strategies for this data-deficient species. Aflafal stream is a spring-fed channel bordered by grazed grasslands, whereas N’Ougouni stream retains willow-poplar stands but is modified by irrigation weirs and cultivation. During spring, we performed non-lethal stomach flushing and identified prey to family level, analyzing functional feeding groups and dietary patterns. Trout exhibited generalist feeding strategies, with diet composition differing between sites in ways consistent with expected differences in prey availability based on habitat characteristics. Both populations relied primarily on FPOM-dependent taxa (collector-filterers and collector-gatherers), but N’Ougouni trout consumed significantly more shredders, reflecting greater allochthonous organic matter inputs from woody riparian vegetation. These findings suggest that dietary analysis may provide complementary insights into habitat quality and prey community structure in threatened trout populations, a hypothesis requiring validation through concurrent benthic sampling. For the endangered Draa trout, integrating feeding ecology into monitoring frameworks may complement traditional bioassessment approaches and support evidence-based conservation management in Mediterranean mountain streams where baseline ecological data remain critically limited.