Epiphytic Lichen and Bryophyte Vegetation as a Bioindicator of Air Pollution

The Recent Transition in Industrial Areas of Fukuoka Prefecture

Abstract

The regional differences and changes with year in total air pollution levels in the main industrial zones of Fukuoka Prefecture, the Omuta and Kitakyushu areas, were evaluated on the basis of the epiphytic lichen and bryophyte vegetation on the tree trunks of shrine woods. The 1st investigation was made in the preiod from 1978 to 1979 to learn the regional differences and the 2nd investigation in 1982 to manifest the chronic changes.
In order more reasonably to determine air pollution levels, a new index “IAP” is devised instead of the “IAP” of LeBlanc & De Sloover (1970) in the present study: preparatorily, the IAP index was given at each spot (50×200 cm2 quadrat), and then the new index IAP at a given quadrat is expressed as the arithmetic mean of the four IAP values including those at the relevant quadrat and its adjacent four quadrats, but excluding the lowest value among them.
In both investigations, a considerable correspondence was recognized between the regional differences in the IAP value and those in the air pollution level which was indicated by the sulfur oxides concentration measured by the lead dioxide method.
The IAP levels determined in the 2nd investigation were, in general, higher than those of the 1st one in the two areas. This fact may suggest that the chronic total air pollution level is changing for the better condition in both areas. The increasing tendency of the IAP values was more obvious in the Kitakyushu area than in the Omuta area.
As a result of the analysis of the species composition and its chronic change in the zones classified by the IAP values, a general reciprocal relationship was found between the specific sensitivity of epiphytes as represented by the number of companion species per quadrat and the air pollution levels.