First inventory and faunistic particularities of the chironomid population from a 6th order section of the sandy River Loire (France)
Garcia, Xavier-François; Laville, Henri
Archiv für Hydrobiologie Volume 147 Number 4 (2000), p. 465 - 484
published: Feb 11, 2000
ArtNo. ESP141014704005, Price: 29.00 €
The chironomid populations of a 40 km section of the middle Loire (Tours region) were studied for the first time. Six collections (distributed over the years 1994 to 1996) of pupal exuviae and benthic pupae were made from April to November, in the main river bed, at 4 sites of this potamal zone. A total of 12,073 specimens were sorted and 117 species or taxa identified. Thirty one are new for continental France, in particular Polypedilum acifer TOWNES and Saetheria reissi JACKSON, two dominant species. Among these, three genera are new: Hayesomyia, Robackia and Saetheria. A new pupal exuvia which has only been noted in the Loire has been recorded: Chironomus Pe23 (LANGTON 1995). A comparison of the middle Loire chironomid fauna with that of the potamal zones of five large European rivers - Rhône and Garonne (France) - Meuse (Belgium) - Pô (Italy) - Rhine (Germany) - confirms the diversity and faunistic originality of the middle Loire using several descriptors such as diversity indexes, rarefaction curves, equitability index, distribution of species abundance, number of "endemic" species and distribution of dominant species. Causes of the high specific richness observed, as well as rare species abundance or scarcity, are discussed taking into account functional characteristics of the River Loire's potamic parts such as the connectivity pattern. The relationship between high biodiversity and large, sandy rivers is also discussed using similar results obtained on two other large sandy rivers: the Pô and the Elbe (Germany) rivers.