C. M. van Herk

BIOINDICATION: THE COMMUNITY APPROACH

Two main methods for estimating air pollution with lichens were developed at the end of the 1960s: the Index of Atmospheric Purity (LAP) by De Sloover and LeBlanc [24] and LeBlanc and De Sloover [73], and the qualitative scale for estimating SO2 pollution by Hawksworth and Rose [56]. Since then, researchers have more or less modified these two basic methods, taking into account regional knowledge on lichens and on patterns of air pollution. All methods currently in use can still be classified as “quantitative” and “qualitative”, the latter often also indicated as the “community approach”.

Epiphytes on Wayside Trees as an Indicator of Eutrophication in The Netherlands

The present method was developed in 1989, following recognition that ammonia pollution was a major threat to vegetation (forests, heaths, bogs, fens, mires), soil and drinking water in The Netherlands (see chapter 5, this volume). It has been tested extensively over the last 12 years in most parts of the country [5].