Growth rate of epihytic lichens as a bioindicator : Air Pollution and Forest Decline. 14th International Meeting for Specialists in Air Pollution Effects on Forest Ecosystems

1989

S. 445-446

1 Tab., 6 Lit. Ang., En, Zfsg. En

Unselbständiges Werk

200034776

Epiphytic lichens are relatively aboundant in some areas where conifers are believed to be damaged by air pollution. This relationship has raised several hypotheses: Lichens may benefit from the deposition of nutrients; Lichens may be due to the increase in light on branches of trees with needle loss; Lichens may have an allelopathic influence on needles or correspondingly needles on lichens. Changes in growth by direct measurement of biomass was used as an easy method to study the hypotheses. For this purpose, the lichens (Hypogemnia physodes) were placed on plastic conditions of the area. The lichens were wetted daily, except for a two day recovery period in the middle of the experiments. Before intial and final weighings the lichens were dried gently in conditions simulating a hot summer day. In an experiment the nitrogen concentrations of the simulated rain water was O, 1.3, 4 or 8 mg NH4NO3 1-1. The growth was significantly faster at all n levels compared to the N-free solution.