Cambiamenti nell’avifauna acquatica svernante nellaRiserva Naturale Regionale Tevere-Farfa (Lazio) trai periodi 1970-1983 e 1991-2005

Brunelli M., Sorace A.,



Abstract:

We compared the abundance of some waterbirds in the Natural Regional Reserve Tevere-Farfa (central Italy) between 1970-1983 and 1991-2005 periods. The Reserve includes two main wetlands: a lake area and a river area. The species feeding in the waters of the lake (Anas penelope, Anas acuta, Anas clypeata) decreased in numbers from the frst to the second period, likely due to instability of the lakebed and eutrophication processes. However, the decrease of Anas acuta, Anas clypeata also agrees with their negative trends in Europe. The species feeding in the waters of the Farfa river (Podiceps cristatus, Phalacrocorax carbo, Aythya ferina) increased in numbers. The increases of Podiceps cristatus, Phalacrocorax carbo and Larus michahellis can probably be related to the expansion of their breeding populations, in Italy and Europe. The increased number of Aythya ferina and Anas strepera disagrees with the negative trend of their populations in Europe. However, Italian wintering population of the latter species increased in the last years.