EFFECT OF CHANGE IN LAND USE ON BREEDING BIRDCOMMUNITIES IN A SILESIAN FARMLAND (SW POLAND)

摘要

Two study areas, 210 ha (A) and120 ha (B), have been selected. Arable groundsdominated (92%) in the study area A, while mead-ows (63% in 1989 and 47% in 2003) - in the studyarea B. The changes in land use in both studyareas have occurred in 2003 comparatively with1989. In the study area A, an increase of the areawith maize (from 1.1 ha to 38.4 ha) and oat (from5.6 to 28.4 ha), and decrease in area of the rape(from 41.3 to 0.3 ha) and root plants (from 16.7 to6.4 ha) have been recorded, while the clover andbroad bean have totally disappeared as cultivatedplants. In the study area B, a conversion of somedry meadows into arable grounds and an aban-donment of more than half of the remaining areaof meadows has been carried out. The landscapein the study area A was more fragmented in 1989than in 2003, while in the study area B the reversewas true. On average, cereal areas increased - es-pecially wheat (from 1.5 to 2.4 ha), maize (from0.6 to 3.8 ha) and oat (from 0.6 to 1.9 ha), whilerape areas decreased (from 2.0 to 0.3 ha). Themapping method has been employed to show theeffect of these changes on breeding bird commu-nity in both years (1989 vs. 2003). In the studyarea A, density (pairs x 100~(-1) ha) of the SkylarkAlauda arvensis (28.1 vs. 17.1) and Marsh War-bler Acrocephalus palustris (12.9 vs. 2.4) has sig-nificantly decreased; while that of Corn BuntingMiliaria calandra (1.4 vs. 8.1) and gallinaceousbirds (2.9 vs. 8.1) has significantly increased overthe last 14 years. The most numerous species in the group of gallinaceous birds, the CommonQuail Coturnix coturnix, probably benefits fromthe enlargement of oat and barley cultivations.The Skylark was negatively affected by the en-largement of study areas with cultivated plants,especially with the wheat and maize. The CornBunting has been, probably, positively affected bythe enlargement of maize and barley cultivations,as well as from the warming effect. The decline ofthe Marsh Warbler could have been caused by thedecrease of the area with rape cultivations but itmay also reflect short-term fluctuations. In the study area B, only densities of theChaffinch Fringilla coelebs and Blackbird Tur-dus merula have significantly increased, and nostatistically significant declines were recorded.These increases can be linked to changes in theage structure of tree and shrub stands in the ex-isting small forests, clumps and hedgerows, butthese species show probably a general increase innumbers over large areas of farmlands in Polandand possibly in some other European countries.