|
Scarton, F.: Distribuzione ed abbondanza di Laridi e Sternidi sugli spazi acquei della laguna di Venezia. (Distribution and abundance of gulls and terns on Venice lagoon waters)Bollettino del Museo civico di Storia Naturale di Venezia, 58: 195-207, 2008.
In 2001-2003, seabird boat transects were made each month between May and July. The area encompasses the southern lagoon of Venice and a marine strip up to about 5 km from the barrier island of Pellestrina. Each month 25 transects of about 1 km each were done, for a total length of 221 km over the entire study period, counting all the birds seen from one side of the boat up to a distance of about 250 m. Most (41%) of the transects showed no occurrence of birds, with a mean of 6.6 + 3.6 birds/100 ha, a mode of 0 and a median of 4.1; no statistical differences were observed among the different transects, or between lagoon transects (6.3 birds, N=12) and sea transects (6.9 birds; N=13). Significant differences were observed among years. Geostatistical analysis for the four commonest species showed that: 1) Black-headed Gull used the innermost part of the waters, near the mainland; 2) Yellow-legged Gull was observed both in the lagoon and in the sea; 3) Little tern was also observed both in the lagoon and at sea, but never at more than 4 km from the colonies; 4) Common Tern also used both spaces, up to ten km from the colonies: 5) Sandwich Tern was mostly observed at sea, up to at least 15 km, probably more, from the colonies. |
|
Scarton seabirds Venice lagoon.pdf (1.155.203 Bytes) |
|
(Seite in 0,01 Sekunden erzeugt.) |