BREEDING BIRD COMMUNITIES IN FRAGMENTED WETLANDS

The breeding bird communities present in 33 isolated wetlands in the P o plain (northern Italy), ranging in size from 0.3 to 63 ha, were inve stigated in order to evaluate the effects of area, isolation and habit at diversity on community structure. In simple and multiple regression s, the effect of area was always preponderant (r2 = 64-83%). No other variables affected the number of species nesting exclusively within th e wetlands while habitat structural diversity and isolation significan tly increased the explained variance of the total number of species an d of other community variables. The S.L.O.S.S. (Single Large or Severa l Small) debate is criticized where species level studies are not carr ied out.