Über den Einfluß von Standortfaktoren auf die Besiedlung des bayerischen Hochgebirges durch Waldameisen (Formica spp.) (Hymen., Formicidae)

During several years the density of nests ofFormica spp. was determined in the State Forests of the Bavarian Alps using the statistical methods of strip survey. The measured density was between 0.32 and 17.78 nests/ha and the calculated abundance on a total forest area of 108269 ha were 221212 nests ofFormica spp., 85% of which wereF. aquilonia and 15%F. lugubris. The typical wood ant species of the lowland were very rare in the mountain region and their nests made up less than 1%. The most important habitat factors (soil, altitude and exposition as well as type, age and density of the stands) were investigated in regard to their impact on the distribution of mountain ants species. Results are summarized in tables. It could be shown that the stand, especially its density was the most important factor which determined the presence of mountain ant species in their colonization region between 700 and 1,800m above NN.