Succession of fungi and fauna during decomposition of needles in a small area of Scots pine litter

Abstract

During micromorphological investigations on Scots pine litter, several decomposition stages have been recognized on fallen pine needles, each being associated with the activity of animal and microbial organisms, both. To well-known fungal successions that have been so far described by mycologists we must add succession of animal groups such as nematodes, amoebae, enchytraeids, sciarid larvae, oribatid mites and earthworms. A bacterial development was observed in the L2 layer, following penetration by microfauna (nematodes, amoebae). After that stage pine needles were actively tunnelled by enchytraeids, sciarid larvae and oribatid mites and at the same time were nibbled on by epigeic earthworms (L2 and F1 layers). When the fine root system of pine developed through accumulated old needles (F1 layer), mycorrhizal fungi penetrated the needles and seemed to impede any further bacterial development. Pine foliar tissues were progressively incorporated into the fecal material of earthworms and other members of the soil fauna. A more realistic scheme was suggested for plant litter decomposition in moder humus.