Present i futur de l'avifauna dels secans de caire estèpic de la plana de Lleida

Abstract

The Lleida plain in western Catalonia gives refuge to a still rich and diverse assemblage of steppe birds, of national and international importance. These birds are rare in Europe and have their last refuge in the Iberian peninsula, which for some species contains a significant percentage of the world breeding population. Within this context, the steppe bird populations of the Lleida plain are in some cases numerically important. This is so for the Little Bustard (Tetrax tetrax) and the Roller (Coracias garrulus), the bulk of whose populations in north-eastern Iberia are found in the Lleida plain, with numbers for the Little Bustard even larger than the total population in France or Italy. In other cases, the importance is biogeographical. Indeed, the Lleida plain is the distribution limit of the Lesser Grey Shrike (Lanius minor) and Dupont?s Lark (Chersophilus duponti), both seriously endangered in the Iberian Peninsula. Other notable species still found in the area are the Black-bellied Sandgrouse (Pterocles orientalis) and the Pin-tailed Sandgrouse (Pterocles alchata), both seriously endangered in Catalonia, the Short-toed Lark (Calandrella brachydactyla) and Lesser Short-toed Lark (C. rufescens), the Calandra Lark (Melanocorypha calandra), the Stone Curlew (Burhinus oedicnemus), Montagu?s Harrier (Circus pygargus) and the Lesser Kestrel (Falco naumanni). At present, most of these species have breeding populations below the minimum viable threshold, fragmented and unconnected to other nearby populations, and are experiencing dramatic population declines. The massive transformation of traditional dry farming into irrigation farming, already started, as well as progressive agricultural intensification and the substitution of traditional activities and land use by other industrial, stock-rearing or service activities, is the main factor leading to this alarming situation, and threatens the disappearance of the steppe habitats, forgotten until now by conservation pol