Abstract: Background: After a brief description of the study area and of the sampling methodology, the researchers present the commented list
of beetles identified during the period 2013-2014 in the wetland complex of Sidi Moussa-Oualidia. Materials and Methods: Samples of
the fauna of beetles are taken by traps barber, quadrat, sight hunting and threshing trees using the Japanese umbrella, in order to ensure
almost complete coverage of habitat types. Results: Surveys conducted in four stations, have culminated in the identification of 40 species
distributed in 24 tribes. Amongst these species, 47% are detritivores, 28% phytophagous, 17% predatory and 8% necrophagous. The
trophic organization of the species is arranged by hierarchization from the shore where the predators and the granivores are preponderant
towards the interior of the cultivated lands where detrivores dominate widely. The geographical distribution of the species includes
several distinct categories: Mediterranean species, North African species, Moroccan endemic species and species with large distributions.
Conclusion: The completion of this study allowed us to identify 40 species of beetles predominantly Mediterranean and 22% of endemic
species. The composition of the population reveals an ecosystem in the process of degradation. These results should alert the authorities
responsible for the danger that runs the complex and the urgency of taking appropriate measures to safeguard it.