Bioindication/Biomonitoring can be done in various ways. There are methods using the "authochtoneous" higher plant vegetation in order to get knowledge about environmental conditions in general and others employing higher plants such as grass cultures or tobacco plants for detecting special pollution impacts.
Right at the beginning it should be noted that great care must be taken in order to avoid misleading expressions. Some of the remarks mentioned here has been derived from P.L. Nimis (Trieste). Firstly, it should be noticed that the term "(bio)monitoring" means "observing". Thus, we monitor organismns not pollutants or environmental conditions. We monitor ecological conditions via organismns by interpreting their behaviour rep. their reaction towards natural and anthropogenic influences. Secondly, it is not precise but rather wrong when saying that some organismns (esp. lichens and bryophytes) can be used for the indication of air quality (or "air purity" or "air pollution"). What do these terms mean? How can air quality or air purity be defined? Pure air contains 21 % oxygen, 78 % nitrogen, 350 ppm carbondioxide and some amount of inert gases, thus anything additional will be a pollutant. But, it that true? For example the air within mediterranean sclerophyllous shrubland (macchie or garigue) can contain high concentrations of hydrocarbons emitted by the plants. Are they pollutants? Apart form this, it is evident that organismns do not solely react on composition of ambient air but being also sensitive towards air humidity, radiation, microclimate in general as well as substratum properties. Hence, the term "bioindicators indicate the quality of air" is too easy and not precise. Therefore it is recommended to substitute this expression by terms like "ecological conditions" (of a site). Alternatively, for areas where pollutants are known to play a role, the expression "immission-ecological indication" may also hit the target. However, the best way may be the employment of "deviation from normality" or "alteration from natural conditions" (Loppi et al. 2001). The deviation from "normal" conditions can be defined by statistical treatment and contains both, natural as well as anthropogenic influence, thus providing a good description of what is actually dealt with.
These websites are based on lectures held at LIMON (NATO Advanced Workshop, Orielton Field, Wales, 8/2000) and at the EURASAP Workshop (Sofia, 4/2001). The main focus is on bioindication/biomonitoring with lichens, however, some of the more general aspects can also be related to studies with bryophytes, higher plants or even animals.
Due to the high number of work carried out using organisms as biological indicators it is hardly possible to list all the slight differences occuring between methods. Therefore, this web will provide a review of the most widespread and frequently used techniques in central europe. The selection of methods is of course subject to the author's point of view and may miss import aspects; but nevertheless, I hope that this presentation helps a little bit in getting an overview over used techniques which maybe extremely helpful for beginners in this field.
First of all, there has to be differentiated between
Indication by presence resp. absence of species
*As biomonitoring/indication with lichens observing accumulation of various pollutants in the thallus is a broad topic, this will not be discussed within this presentation