Habitat constraints of Synchaeta (Rotifera) in North Italian lakes (Trentino-South Tyrol)

摘要

Species of the rotifer genus Synchaeta, common in pelagic and littoral zones (Hollowday 2002), frequently comprise an important component of the zooplankton of temperate lakes (Miracle 1977). Their identification is challenging (Ruttner-Kolisko 1974, Koste 1978, Hollowday 2002), however, particularly in preserved samples because features such as body size, corona, foot morphology, and position of lateral antennae are distorted and thus are no longer useable in identification. These difficulties explain why Synchaeta identification is limited to group (sensu Ruttner-Kolisko) or to genus level (Fer-nandez-Rosado & Lucena 2001, Thorp & Mantovani 2005, Tolotti et al. 2006). Studies in which specimens are identified to species level are rare (e.g., Jersabek 1995, Rougier et al. 2000). Nevertheless, investigations regarding the distribution of Synchaeta in relation to environmental variables are needed for a better understanding of ecological processes in lakes. Our study of 126 lakes of the lake-rich Trentino-South Tyrol region of Italy represents the first attempt to investigate Synchaeta distribution in this region.