INVERTEBRATE FAUNA OF NORWAY SPRUCE (PICEA-ABIES) SAPLINGS AND ITS CONNECTION WITH THE NITROGEN, SULFUR AND PHENOLICS CONCENTRATION OF THE NEEDLES

The composition of the invertebrate fauna living on young Norway spruc e (Picea abies) branches was studied in northern Finland both in urban and rural areas during the summer months of 1988. Attention was given to the total nitrogen, sulphur and phenolics concentration of the nee dles. The material consisted of 52627 invertebrates from 300 separate spruce saplings. Mites formed the majority of the invertebrates. Most numerous were Ameronothrus dubinini, Diapterobates humeralis and Cerat oppia bipilis. Springtails and spiders were also numerous. The inverte brate abundances were highest in the urban areas of Isko and Linnanmaa , where the sulphur and nitrogen concentration of the needles was high and the phenolics/nitrogen ratio low. The lowest invertebrate abundan ces were found in Rusko, the most urban area, and Taivalkoski, the mos t rural area. Nitrogen and sulphur concentrations were highest at Rusk o and lowest at Taivalkoski. Possible reasons for the results are disc ussed.