ENVIRONMENTAL DNA: A POSSIBLE TOOL TO EVALUATE THE VERTEBRATE BIODIVERSITY USING WATER SAMPLES OF THREE SICILIAN LAKE

Abstract

Freshwater ecosystems play a key role for the biogeochemical cycles and are subject to several anthropic impact that cause a biodiversity loss. Conventional census methods seem to be insufficient and not very convenient for the detection of species. The organisms inhabiting these sites continuously release DNA, called "environmental DNA" (eDNA), through cells, excrement, gametes and/or decomposing material and its evaluation could revolutionize the monitoring of biodiversity (HARPER et al., 2019; SCHENEKAR, 2023). On the other hand, today there are considerable doubts about it: seems to be the non-existence of well-defined protocols which depend on the sampling site, environmental factors and extraction methods; degradation processes are very rapid and the costs of evaluations are very high (many samples are needed in different points). The aim of this study (part of RTDA-PON project) was to fine-tune the sampling and eDNA extraction protocol, reducing the costs and evaluating the potential of this method compared to the conventional methods. Another aim was evaluating the biodiversity of vertebrate in some Sicilian Lake for which until to date no more is known. In this study, the eDNA technique was used for the first time in three Sicilian lakes: Poma Lake, Piana degli Albanesi Lake and Scanzano Lake.The water sampled in each site was filtered and eDNA was extracted using extraction kit. Metabarcoding analysis was performed by IGA Technology Services s.r.l. The results showed the possibility to understand which types of phyla, class, order, family, gender, or species lives in these sites. The species not captured or not sighted using conventional methods were detected thanks to the use of eDNA and vice versa highlighting that the evaluation of eDNA can be useful to evaluate not only aquatic species but also other species that use these sites as a source of supply. Another important result was the possibility to detect DNA of species not typical of freshwater sites highlighting the contamination process. eDNA is a very important tool to evaluate the biodiversity and the health status of the environment, but on the other hand, for a more complete census, it is very important use also other conventional methods at the same times. Our preliminary results showed that eDNA method have the potential to replace the traditional methods of census but it is not yet the time to do it, using both methods is surely the best approach.