Stöckli, S., M. Jenny & R. Spaar
(* = Kurzbeitrag)
Eignung von landwirtschaftlichen Kulturen und Mikrohabitat-Strukturen für brütende Feldlerchen Alauda arvensis in einem intensiv bewirtschafteten Ackerbaugebiet.
(von 1994 bis 2006 vergeben)
Alauda arvensis, Klettgau, crop suitability, territory size, territory shift, microhabitat structure
Kulturland, Landwirtschaft, Vegetationsstruktur, Mikrohabitat-, Habitatwahl, Reviergrösse, Revierverschiebungen, Brutbiologie
Schweiz, Schaffhausen, Klettgau
Suitable crops and microhabitat structures for breeding Skylarks Alauda arvensis in an intensively farmed area. We studied the development of vegetation of different crops and its effect on nest site selection and territorial behaviour of Skylarks Alauda arvensis in an area of northern Switzerland during the breeding season 2002. The suitability of the different crops for nesting showed a seasonal pattern according to vegetation development: At the time of egg-laying, average vegetation height and cover were 50 cm and
52 %, respectively. Microhabitat structure was important for nest-site selection: Vegetation height and cover at the nest site were both significantly lower compared to the surrounding field. First nests in April were situated in wheat and barley fields. When these fields became too high and too dense in early May, spring-sown cereals such as emmer (an old wheat species) was an excellent alternative during May. In June, nests were situated predominantly in sugar beet, maize or potato fields. Territory size was 1.8 ha in the Langfeld area and 1.5 ha in the Widen area and, compared to other studies, relatively small. A linear regression analysis showed that territory size increased with a decreasing amount of wildflower strips and an increasing amount of emmer and einkorn in all months. In May, territory size decreased with an increasing number of crop types in the territory. The territories were shifted between April and June by 6 to 81 %, including more wildflower strips and grassy farm tracks and less winter cereals in June compared to April.
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