Use of the Drana Lagoon (Evros Delta, Greece) by threatened colonially nesting waterbirds and its possible restoration

Abstract

Six species of waterbirds nested colonially on small islands in the Drana saltwater lagoon in the Evros Delta from 1980 to 1986 and in the freshwater lake created in 1989, namely avocet Recurvirostra avosetta, collared pratincole Glareola pratincola, common tern Sterna hirundo, little tern Sterna albifrons, gull-billed tern Sterna nilotica and Mediterranean gull Larus melanocephalus. The favoured islands provided greater isolation, were larger, and had greater cover of plant species preferred by the birds. The most important habitat factor affecting the choice of bird populations in general was isolation of islands. The gradual concentration of most species in the Drana lagoon was due to habitat alteration, predation and disturbance in coastal habitats resulting in scarcity of suitable breeding habitat. The Drana lagoon had a prominent conservation, scientific and economic value and therefore its restoration is recommended by reflooding with sea water, which would better ensure the preservation of the values of the area.