(* = Kurzbeitrag)
Einfluss des Lebensraums auf die Populationsdynamik des Neuntöters Lanius collurio am Fuss des Waadtländer Juras.
(von 1994 bis 2006 vergeben)
Reviere, Brutaktivität, Fortpflanzungswahrscheinlichkeit, Siedlungsdichte, Bodennutzung, Lebensraumverändeerung, Lebensraumqualität, Landwirtschaft, Heckenpflege
Lanius collurio, Sylvia communis, Saxicola torquatus, Saxicola rubetra
Neuntöger, Dorngrasmücke, Schwarzkehlchen, Braunkehlchen
The influence of the habitat on the population dynamics of the Red-backed Shrike Lanius collurio. Over a period of twenty years, 302 territories of Red-backed Shrikes were identified and described, in 291 of which breeding was confirmed. Over time land use in the study has changed, with an increase of oil-seed rape and a decrease of cereals and maize. 84 % of the territories contained hedges or small patches of thorn bushes. 80 % of territories were facing south or east, 60 % contained patches of steep slope. The shrub layer contained 58 bush and tree species but only 16 occurred with a frequency of >10 % and four thorny species dominated, occurring in >70 % of the territories. Territories contained a mean of 7.4 bush and tree species. 92 % of territories contained dominant lookout posts. The percentage of open ground or sparse vegetation was low. Cereals, permanent pasture and intensive meadows were the land-use types most frequently associated with territories (with or without reproduction). Probability of reproduction was highest where two types of crops were present: rape-maize, pasture-rape, pasture-maize, pasture-cereals. Pastures were over-represented in low-altitude territories but not in the densely occupied foothills of the Jura. There was no significant correlation between population density and the occurrence of the six main crops. In 20 % of territories reproduction was confirmed only once in 20 years, in 56 % four or more times. 62 territories were occupied in more than ten years. The proportion of suitable territories continues to decline, posing a threat to the long-term survival of the population.
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