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Rudin, M., P. Horch, I. Hugentobler, U. Weber & S. Birrer

Bestandsentwicklung von Brutvögeln im ökologisch aufgewerteten St. Galler Rheintal.

2010

107

81–100

Key words
(von 1994 bis 2006 vergeben)

Bestandesentwicklung, Artenzahl, Bestandesdichte, Neststandort, Kulturland, Naturschutzgebiet, Landschaftsaufwertung, Ausgleichsmassnahmen

Schlagwort_Vogelart
(wissenschaftlich)

Coturnix coturnix, Vanellus vanellus, Alauda arvensis, Anthus trivialis, Motacilla flava, Emberiza calandra, Luscinia megarhynchos, Sylvia communis, Lanius collurio, Emberiza citrinella, Columba oenas, Streptopelia turtur, Phoenicurus phoenicurus, Hippolais icterina, Phylloscopus trochilus, Rallus aquaticus, Luscinia svecica cyanecula, Saxicola torquatus, Locustella naevia, Acrocephalus palustris, Acrocephalus scirpaceus, Emberiza schoeniclus, Ciconia ciconia, Carduelis carduelis, Sylvia borin

Schlagwort_Vogelart
(deutsch)

Wachtel, Kiebitz, Feldlerche, Baumpieper, Schafstelze, Grauammer, Nachtigall, Dorngrasmücke, Neuntöter, Goldammer, Hohltaube, Turteltaube, Gartenrotschwanz, Gelbspötter, Fitis, Wasserralle, Weisssterniges Blaukehlchen, Schwarzkehlchen, Feldschwirl, Sumpfrohrsänger, Teichrohrsänger, Rohrammer, Weissstorch, Distelfink, Gartengrasmücke

Schweiz, St. Gallen, Rheintal, Altstätten, Kriessern

deutsch

Abhandlung

Population trends of breeding birds in the ecologically upgraded Rhine valley (canton of St. Gallen, Switzerland). – Since 1993 numerous areas in the intensively farmed plains of the Rhine valley near Altstätten (canton of St. Gallen) have been ecologically upgraded. We studied the impact of this upgrading on species richness and population density of breeding birds on cultivated land. For this we recorded the population densities of selected farmland birds in a study area of 12.6 km2 in 1988/89, 1999 and 2006 (table 2). In 1988 this area presented itself mainly as an intensively farmed plain. In the centre there were still 68.7 ha of wetlands, remnants of previous reed beds, which were protected as nature reserves by 1995. There were linear structures (channels and tree hedges) spread over the whole study area, with a total length of about 39 km. As from 1993 about 97 ha of new ecological compensation areas were created. These are concentrated round the nature reserves. 22 breeding farmland bird species were recorded. More species were observed in the nature reserves than in the other land-use types (high-quality ecological compensation areas, compensation areas of no special quality created according to the regulation of direct payments, linear structures and remaining cultivated land). The number of species remained stable in the entire study area, it increased in the ecological compensation areas (high-quality and those of no special quality) and declined in the remaining land-use types: only slightly in the nature reserves, considerably in the linear structures and in the remaining cultivated land. We were able to calculate population trends for 12 of the more common species: In the entire study area the increase and decline of populations balanced each other. The populations of Eurasian Stonechat, Eurasian Reed Warbler, Willow Warbler, Red-backed Shrike and Common Reed Bunting increased. During our study period, the Eurasian Stonechat was first detected in 1990. Northern Lapwing and Tree Pipit disappeared from the study area as breeding birds, the population density of Eurasian Skylark declined, likewise that of Icterine Warbler and Marsh Warbler. The population of Common Grasshopper Warbler fluctuated without a clear trend, the density of Yellowhammer remained stable. Population increases prevailed in the nature reserves as well as in the high-quality ecological compensation areas, however, in cultivated land, in ecological compensation areas of no special quality and in linear structures negative population trends prevailed. The project in the Rhine valley is one of the few examples of a large-scale project for the enhancement of habitat where an evaluation of success was made. It shows that ecological compensation areas of a high-quality and nature reserves can have a positive effect on the diversity and density of farmland birds. In intensive farmland, however, both the number of species and their population densities continued to decline.