Eichen im Aargau – eine besondere Verantwortung für das Fricktal | Oak in the canton of Argovia – a special responsibility for the Fricktal
A targeted nurturing of oak in the canton of Argovia goes against the natural development of forest stands where the dominant, naturally occurring species is beech. Because of this, afforestation with oak is both work intensive and costly and is therefore concentrated on sites where silvicultural, economical and ecological aspects have been taken into account. With the help of a simple model showing areas where, above all, oak is nurtured, comprehensively mapped forest stands were classed according to competitiveness and correlated to thermal levels, that represent an important site factor for oak. One important aspect surrounding the issue is the preservation of genetic resources and an adequate supply of appropriate seed from chosen autochthonal, indigenous oak stands. In addition, the endangered population of middle spotted woodpecker, which is tied to widespread sites of aged oak-rich deciduous stands, should be fostered. Taking ecological priorities into account a possible area to nurture oak has bee...
Autochthon oder allochthon? Ein molekulargenetischer Ansatz am Beispiel der Eichen (Quercus spp.) in der Schweiz
Autochthonous forests are considered to be valuable genetic resources, and their conservation is incorporated into many national forest programmes. The methods applied so far often do not allow to distinguish between autochthonous and allochthonous stands. Therefore, alternative methods are needed. In this study, we analyse spatial patterns of variation of chloroplast DNA to estimate the extent of the human influence on oak stands in Switzerland.
Die Populationsdynamik Von Canthocampt Us Staphylinus (Jurine) (Copepoda, Harpacticoida) Im Litoral Des Bodensees
The population dynamics of Canthocamptus staphylinus in the littoral zone of Lake Constance are described (fig. 2). Adult animals aestivate as cysts. The main part of the population emerges from the cysts in autumn. During the resting stage and the first spell after emerging, mortality is very low (fig. 3). Reproduction, expressed as numbers of ovigerous females, begins in November and reaches its maximum in January. The new generation becomes adult in May/June and encysts without previous reproduction. According to Sarvala (1979) it may be possible, that in littoral populations dormancy is induced by long day periods and temperatures of over 12° C (figs. 1, 2). In the profundal zone C. staphylinus also forms cysts, however, both light and temperature are not likely to induce this stage in depths of over 60 m.