Bibliothèque Tour du Valat

Se connecter

Mot de passe oublié ?
Pas encore inscrit ?

La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Détail

Ajouter au panier

Ajouter au panier

Lien vers la notice

Titre :	Population increase and sequential habitat occupancy in the Common Buzzard Buteo buteo in northern Germany (western Schleswig-Holstein) during 1966-2006 (2007)
Auteurs :	Guenther Busche, Auteur ; Achim Kostrzewa, Auteur
Type de document :	Article
Dans :	Vogelwarte (45(3) AUG 2007)
Article en page(s) :	209-217
Langues:	Allemand
Résumé :	The investigated area of 628 km(2) is very sparsely wooded (0,1-1,3 % woodland) and stretches from the western marsh- and lowlands close to the coast of the north sea to the more elevated "Geest" in the east. During 22 control years between 1966 and 2006 776 nesting pairs were assessed in four different habitat types (Fig. 1):a) The mature woods of the "Geest" a more hilly upland (about 50 meters above sea level) made 784 hectare and carried 12 pairs in the beginning and 33 in its early peak year in 1977 and in 1993 34 pairs, respectively. In this traditional woodland habitat buzzards have lived ever since. Historical data from 1948-55 showed 3-4 pairs nesting.b) In the so-called "Knicks" hedgerows with mature trees planted (1770-1870) within traditional farmland as windbreakers, which surrounds the woodland, the first pair was found in 1966 and the population peaked at 35 pairs in 1993.c) The lowlands and moors were used as farmland with some small pieces of woodland on drained moors and some plantations. Here the colonisation began in 1974 and 1977 in good vole years and peaked with 25 pairs in 1993 and 33 pairs in 2006, respectively.d) The marshland has been used since 1981 (one pair during a peak vole year) and culminated in 2003 with 13 pairs. The marshland is only poorly wooded (0,1 %), mostly plantations for shelter around farmhouses. Nesting sites in all habitat types but a) comprise of small woods to single trees (Tab. 1). For a) and b) type of habitat combined we found a positive correlation to its vole rank (Fig. 2). Due to its wood structure the area is quite easy to check and we are sure to have found almost all nesting pairs during the control years, especially because GB started his work on other bird species in 1960 in the same area and in all habitat types mentioned here.The theory of sequential habitat occupancy requires also breeding results in all habitats tested. Again habitat a) and b) type were quite similar with 1,45 and 1,5 fledged young per brood started. c) gave values of 0,96 and d) 0,85, respectively. These differences were highly significant (Fig. 3). Breeding success in a) and b) type were highly significantly correlated to vole rank (Fig. 4). For type c) and d) habitats, we did not have sufficient data to test against vole rank. In a) type habitat we found highly positive correlations to sum of young fledged and mean sum of young fledged per nest with years of territory use (Fig. 5a-c), as we did for the b) type (Fig. 6a-c).We interpret our results in the sense of a sequential habitat occupancy, because of the sequence of colonisation and the different fitness in the different types of habitat. Historically, from the point of view of raptor destruction since the middle ages up to the 1950's, woodland was a kind of more sheltered or refugial area and later a source of re-colonisation for open farmland. From the point of view of a population ecologist, type c) and d) habitats were sinks, while the woodland a)+b) still acts as a source (Fig. 7).

FAQ

Infos pratiques

Heures d'ouverture et contact

Lundi , mardi et jeudi de 9h à 12h et de 13h à 17h00 : ouverture au public ...

Liens utiles

A-
A
A+