Diversity, habitat use and conservation of freshwater molluscs in the lower Guadiana River basin (SW Iberian Peninsula)

Abstract

1.A study on the distribution pattern and conservation of freshwater molluscs of the south Guadiana River (SW Iberian Peninsula) was carried out between the Alqueva dam and the Atlantic Ocean.2. The knowledge of the distribution and abundance of molluscs before the closure of the Alqueva dam is an important tool for evaluating the potential reduction in diversity and the changes in species conservation status that may occur later.3. Twenty-three species (15 gastropods and 8 bivalves) were found in the study area. The presence of Unio crassus and Potomida littoralis indicates the importance of this basin for the conservation of endangered mussels (Unionidae) in the south Iberian Peninsula.4. Drainage area above the sampling site explained almost 58% of the variation in species richness. Larger drainage areas had a higher number of species, including those endemic to the basin.5. Patterns of habitat use were examined to identify species preferences with respect to the erosional-depositional gradient. Islamia minuta, Pisidium casertanum and Pisidium personatum find their optimum habitat in headwaters, whereas Theodoxus fluviatilis, Mercuria emiliana, Radix auricularia and all unionid species inhabit large and stable habitats downstream without marine influence.6. Populations of invasive Corbicula fluminea were found in the Guadiana River basin, both in rivers with large drainage areas and in brackish waters near the mouths of rivers.

Macroinvertebrates as Indicators of Water Quality in Running Waters: 10 Years of Research in Rivers with Different Degrees of Anthropogenic Impacts

“…According to Brinkhurst & Gelder (2001), several aquatic oligochaetes, including Naididae species, have red blood pigments which aid oxygen uptake and transport, thus they can live in environments with low oxygen. Pérez-Quintero (2007) documented that some Hydrobiidae species were salinity-tolerant, so possibly also conductivity-tolerant, as these variables are closely correlated.…”

Phylogeny, phylogeography, and evolution in the Mediterranean region: News from a freshwater mussel (Potomida, Unionida)

“…Regrettably, the Endangered P. littoralis has been declining in recent decades in all Iberian populations (Barea-Azcón et al, 2008;Pérez-Quintero, 2007) and has suffered a major range contraction in France, being extirpated from the north of its former distribution , which restricts the collection of more specimens.…”

“…As for the remaining four subspecies, no recent data is available, and so the taxonomic status of all these subspecies is still unclear. This is worrisome since Potomida populations (Barea-Azcón et al, 2008;Pérez-Quintero, 2007;Sousa et al, 2008) and other freshwater mussels (e.g. Lopes-Lima et al, 2016b;Sousa et al, 2015Sousa et al, , 2016, have suffered dramatic declines.…”

Distribución y partición aditiva de la diversidad de las comunidades de moluscos de agua dulce en arroyos del Sur de Brasil.

“…Studies of mollusk communities as a whole, especially those focusing on their spatial distribution, are relatively few (e.g., McRae et al, 2004;Souza, Guilhermino & Antunes, 2005;Lewin, 2006;Pérez-Quintero, 2007;Maltchik, Stenert, Kotzian & Pereira, 2010). Studies about their diversity at different scales are lacking.…”