|Town/Region||Cap-Serrat, Mateur, Nefza, Sajanan, Tabarka|
|Categories||Biodiversity, Habitats, Invertebrates|
|Date||7 Jan 2019|
Freshwater Bivalves of the Order Unionida, frequently referred as freshwater mussels or naiads, have a broad geographical distribution that includes all continents except Antarctica with more than 800 species described to date.
They are remarkable organisms with some characteristics that make them, from a biological perspective, very interesting (centenary lifespan, brooding parental care, parasite Glochidia and double uniparental inheritance DUI, etc). Ecologically, they considered as ecosystem engineers and key species due to the crucial functions and services they provide for their wetlands habitats functioning and the biodiversity equilibrium such as water filtration and clarity, nutrient and energy cycling, provision of microhabitat for other organisms, biogeochemical cycles and sedimentation rates. Moreover, due their capacity of bioaccumulation of pollutants, freshwater mussels are successfully used as biomonitors and sentinel species in several ecotoxicological monitoring programs. At the global scale, most of the Unionoid species are decreasing precipitously with high rate of extinction (1.2% per decade). Indeed, 224 (44%) of the 511 freshwater mussel species, belong to the Unionidae family, are classified as Near Threatened or Threatened in the 2015 IUCN Red List of Threatened Species. They are vulnerable to multiple stressors and threats that lead to altered community composition such as Habitat loss, Habitat fragmentation and degradation, pollution, introduction of invasive species and climate change. This global extinction crisis in freshwater mussels has led to a great increase in conservation efforts and causing conservational and social concern.
Nevertheless, a great bias exists in the research effort since the publishing pattern does not always correspond to the hotspots of biodiversity but is concentrated in the northern hemisphere with multiple studies in North America and Europe leaving others regions like Africa blundering in scarce lack of data and information regarding the basic aspects of their freshwater species. In understudied African countries as Tunisia, many doubts and ambiguity still persist in the taxonomy and the distribution of the niaids due to first, the poorly old malacological studies and second, the high phenotypic plasticity, that the mussels exhibit, rendering traditional conchological features as form and colour of limited use for identifying taxonomic units. So, our research project, with holistic integrative bioecological studies, advanced genetic analysis and toxicological approach, is urgently needed to clarify the Tunisian Freshwater mussel’s diversity, to distinguish the real causes of decline and to restore and protect the critically endangered populations in their habitats.
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