Esponenti endofitici, epifitici e fitosaprobi del Lago Trasimeno: Facies autunnale

• Published in: Bollettino di zoologia 1959-01, Vol.26 (2), p.615-636
• Main Author: Di Giovanni, Maria Vittoria
• Format: Article
• Language: English
• ISSN: 0373-4137
• DOI: 10.1080/11250005909439313

The progressive developement of hydrophytie colonies has increased the importance of the phytopbil communities existing in Lake Trasimeno and has transformed the whole lake into a single, extended, homogeneous, litoral region. Observations carried out in the month of October on the single species of water plants have brought to light a series of phytophil animals, the analysis of wich aims to establish their exact relationship with the substratum. The present work stresses in particular the representatives of the zoological world neglecting those of the algal, to wich will be dedicated a further note. The analysis of the communities, from specimens taken at stated distances, shows a certain wealth of composition, but at the same time a notable monotony of distribution. The types founded (Protozoa, Rotifera, Nematoda, Crustacea, Hydrachnida. Insecta, Mollusca) are more in evidence to epiphylon and periphyton, but there exist also a certain number of endophytic forms present especially in the Potamogeton and in the Myriophyllum (Phyrtochironomus severini Goetgh and others). The populations appear on the whole independent of the substratum on wich they live: the same epibionts with a few rare exceptions are to be found confusely on all the water plants without any difference in the botanic order. This, united to the analysis of the surrounding elements, calls the attention once again to the increasing and undoubted stagnation of Lake Trasimeno within the last few decads.