Tuesday, 24 March 2015

Prodiamesa olivacea (Meigen, 1818)
DipteraFamily ChironomidaeSubfamily

In the Pyrenees:
Our analysis showed an increase in P. olivacea distribution during the industrialization process, thus in samples dated about 200 y.b.p. we only found its presence in one lake (Llebreta), this represented 1% of the studied lakes. Actually this species occurs in 11.2% of the sampled lakes, its shighest relative abundance was in lake Helado de Marboré (12.5%) but usually it had low abundances (around the 2% of the chironomid assemblage).
Based on its actual distribution we could see a wide range of altitude tolerances (above and below the treeline) and environmental preferences.
Analyses of the core extracted from lake Redó d’Aigüestortes showed presence of P.olivace, with relative abundance below 1%, about 7.300 y.b.p. and near the present time.

Information sourceComunitats subfòssils de quironòmids de llacs dels Pirineus, Titulació en Estudis Avançats en Ecolologia, Universitat de Barcelona, 2002. Author: Rosa Casanovas

Wednesday, 18 March 2015