THE ECOLOGY AND DISTRIBUTION OF LICHENS IN TROPICAL DECIDUOUS AND EVERGREEN FORESTS OF NORTHERN THAILAND

During three years of research on epiphytic lichen communities as indi cators of environmental change in northern Thailand plots were set up in a range of forest types between 400 and 1600 m in 1991/2 and revisi ted in 1993. Other areas were visited in 1993 and collections made in a wider range of geographical, altitudinal and vegetation conditions i n Thailand. From this data factors influencing the distribution of lic hens in a monsoon climate are outlined and characteristic components o f the lichen flora given at family, generic and where possible specifi c level. Dominant taxa of the montane forests include hygrophilous mac rolichens of the 'Lobarion' that are also a characteristic component o f old growth fagaceous forests in Europe, whereas the evergreen forest s are dominated by moisture-dependent crustose taxa with a trentepohli oid photobiont, and the deciduous dipterocarp forests by often brightl y coloured xerophytic lichens with a trebouxioid photobiont. Taxa are proposed as indicators of forest type including those that are indicat ors of old-growth forests and of disturbance. Quantitative recording o f selected taxa at genus and species level is suggested to estimate ra tes of change in monsoon forests in southeast Asia.