Contribution
Chironomid larval assemblages in the enclosed Rhine-Meuse Delta: spatio-temporal patterns in an exposure gradient on a tidal sandy flat
Smit, Henk.
Archiv für Hydrobiologie Volume 137 Number 4 (1996), p. 487 - 510
49 références bibliographiques
publié: Oct 18, 1996
DOI: 10.1127/archiv-hydrobiol/137/1996/487
ArtNo. ESP141013704002, Prix: 29.00 €
Abstract
Chironomid species composition and distribution in relation to exposure were studied on a tidal sandy flat at seven sites (average depth 0-50 cm), differing in the duration and frequency of the exposure periods. The chironomid assemblages can be divided into an 'upper eulittoral' one, consisting of Chironomus acutiventris, Ch. balatonicus, Einfeldia carbonaria, Stictochironomus histrio, Cryptochironomus sp. and Cladotanytarsus sp., and a 'lower eulittoral' one consisting of Lipiniella arenicola, Ch. nudiventris and Procladius sp. Small S. histrio, L. arenicola and E. carbonaria larvae appeared first on frequently exposed sediments and dispersed later over the entire gradient. Small Ch. nudiventris larvae appeared first at submerged sediments. The high micro-phytobenthos biomasses observed (chlorophyll-a > 150 mg m-2) are probably responsible for the high chironomid densities and biomasses. Predation by waders may have had an important impact on chironomid densities and species composition at exposed sites. The innuence of sediment texture, temperature stress, settlement and migration of early instar larvae, chironomid predator-prey interactions and competition for space between large and small chironomids on the establishment of a zonation pattern are discussed.
Mots-clefs
Chironomid • Rhine-Meuse Delta