According to the National Study on Aquatic Biodiversity Continental established by Prof. M. DAKKI, Morocco is relatively rich in continental waters: natural lakes (found essentially in the Middle Atlas) or dams, rivers, merjas, ‘phreatiques’ waters... These waters harbor a Mediterranean fauna characterized by:
- A relatively high endemic total
- A richness in afro-tropical relics, witness of a hot and humid climatic past (tertiary era).
- An altitudinal distribution different from that of Europe, with a frequent ascension in the Moroccan mountains of species in common with Europe.
- A quite particular ecology, reflecting a hydrology and a Mediterranean climate, with Atlantic and Saharan influences more or less marked.
Our aquatic continental fauna includes all the aquatic macro-invertebrates from the Rotifieres until the Insects and Pisces. The inferior groups (Sponges, Cnidaires, Nemathelminthes, Tardigrades, Gastrotriches), microscopic and still not well known, are not considered.
Global continental aquatic fauna
The inventory (at the level of the Order), based on a selective bibliographic study, is given in Table 12. The principal results can be announced as followed:
- A relatively poor fauna, compared to that of european countries, Asia, and the entirety of the Maghreb: it has only 1575 sub-species, dividied between 646 genuses, 198 famililes, and 37 orders. One must thus consider that this inventory is not exhaustive and represents only 80% of the total real number of species and sub-species (estimated at 2000);
- The Insects, with 1140 species and sub-species, represent 72% of this fauna, with 55% divided between Dipteres and Coleopteres. The Crustaceans represent 14% only, followed by Mollusks, Annelidas, Hydracariens and Pisces, which represent only 2.8-3.3% each. The ichtyological fauna is represented at 36% by imported species. Analysis of the variety (specific richness) by group can be made by the medium number of species that each taxonomic level contains.
The intragenetic variety (the number of species and sub-species by genus) is of 2.4 on average for the entirety of the fauna, with averages even smaller with the groups of essentially running water (Plecopters, Trichopteres, Ephemeropteres, p. ex). The greatest value is among certain famililies of Dipteres, Coleopters, Heteropters, Bivalves...this result shows the existence of a great number of monospecific genuses.
The average number of species and sub-species by family is of 8 for all the fauna, with smaller number for the population of running water than for stagnant waters.
This small diversity constitutes a reason for insisting on the process of conservation, since the protection of one species will often signify the protection of all the genus, at least at the national scale.
Endemic species
The list is presented in Table 13. Among the 1575 ‘taxa’ known in Morocco, 136 species and sub-species are endemic to the country, or an average total of around 8.63%. An equally high proportion gives certainly originality and a great interest in biodiversity of fauna in continental waters of Morocco.
The number of endemic species is unequally divided between different groups:
- Insects: 75 endemic ‘taxa’ (or 55.2% of the total number of endemic species), divided principally between Dipters (26), Trichopters (21), Coleopters (15) and Ephemeropters (10):
- Crustaceans: 39 endemic species (28.7% of the total number), shared especially between Amphipodes (19), Isopodes (8) and Copepodes (7), with two species of Anostraces of the North African genus Tanymastigites and the two Moroccan representatives the Thermosbaenacea;
- Pisces: 11 endemic species, one of whom is extinct (Salmo pallaryi) and all the others among the Cypriniforms (8 species of the genus Barbus, 1 of the complex Varichorinus/Labeobarbus and the Moroccan forme of the Loach of river.
The remarkable presence of the endemic genuses merits a mention apart. it in particular the case, among the Turbellaries, of the monospecific genere Acromyadenium proper to the Atlas. The two species of the genus of Crustaceans Maroccoloana (Isopode) and Maghrebidiella (Amphipode) are equally proper to Morocco.
Endangered species
The inventory of endangered ‘taxa’ is given in Table 14. The number of rare/vulnerable ‘taxa’ is estimated at 137 species and sub-species, among which 110 are endemic to Morocco (without counting one extinct species, Salmo pallaryi) and other North Africans or west Mediterraneans. Sixteen species are considered endangered and twenty as vulnerable, while the great majority about are classed as rare. The verifications remain to be made for thirteen ‘taxa’, indicated in the present work as probably endangered, or at least rare.
The greatest number of endangered species is among the Insects: 87 (63.5% of the total number), followed by the Crustaceans (28) and the Pisces (11). The percentage of endangered species is 8.7 % for the entirety of the inventoried fauna in the country, while the total of 30-100% is recorded for several groups. The most endangered ‘taxa’ (and the greatest number of dangers) exist in the sources or the cold water courses of high altitude or in phreatic waters. This result is completely expected since the list of endangered ‘taxa’ is composed principally of endemics, ‘infeodes’ especially at the waters of mountain masses and in subterranean regions of low plains.
For more details, please consult the following document: National Study on the Biodiversity of Aquatic Fauna, 1998.