Natural Environment Monitoring 2009, No 10, pp. 57-64
POSSIBLE USES OF EPIPHYTES FOR AIR POLLUTION ASSESSMENT IN THE CENTRAL PART OF THE ŚWIĘTOKRZYSKIE (HOLY CROSS) MOUNTAINS
Małgorzata Anna Jóźwiak
Until recently, the problems and anxieties related to air pollution have centred around the concentration of individual pollutants in atmospheric air. In recent years, research into the assessment of the natural environment’s condition has been intensified with the use of bioindicators. An assessment of the environment’s chemical quality, conducted on the basis of biological indicators, is a very good method of checking how living organisms respond to changes in the chemical composition of air.
The objective of the present study has been to provide an assessment of possible uses of epiphytes for specification of the sanitary condition of atmospheric air. The study was conducted in the years 2003-2008 in the area of a forest ecosystem in the central part of the Świętokrzyskie Mountains. The subject of the study was a lichen with a heterometric thallus, Hypogymnia physodes (L.) Nyl. – Hooded Tube Lichen, Genus: Hypogymnia (Nyl.) Nyl., Familia: Parmeliaceae.
In order to determine the dynamics of the Hypogymnia physodes lichen thallus growth under conditions of prolonged, remote acidic ambient concentration, the linear method was used (Nieboer, Richardson 1981). It consisted in the selection of fixed areas (6 sites – trees) where the lichen occurred (Photo 3) and annual measurement of the thallus area. The cumulation levels of heavy metals from the air in the lichen thallus were also measured in the Świętokrzyskie National Park forest ecosystem in relation to the height above sea level. The lichens were exposed at 17 sites in the transect on the northern slope of Mt. Łysiec (Fig. 1) on twigs brought from the Borecka Primeval Forest. The conducted study enables the statement that the lichen biota provides a good indicator of environmental change, which is mainly due to lichen anatomical structure, i.e. lack of the cuticula and epidermis, very low chlorophyll content in proportion to thallus weight, as well as the capacity to absorb moisture in the form of water vapour from the surroundings, together with pollutants found in the air. These features provided the basis for the selection of lichens as bioindicators in the studies by Fałtynowicz (1995), Cuny et al. (2000), Sawicka-Kapusta et al. (2002, 2005); Calvelo, Liberatore (2004). A significant feature of lichens is their widespread occurrence and capacity to cumulate toxic substances in concentrations which are detrimental to higher plants and animals (Puckett 1988; Jones et al. 1991; Jóźwiak 2007).
The study into the Hypogymnia physodes (L.) Nyl lichen thallus growth as well as the volume of heavy metal cumulation in the thallus have enabled an assessment of the possibilities of these organisms being used for air pollution monitoring in the forest ecosystem. It has been concluded that
- lichen biota constitutes a good indicator of environmental change, mainly due to the anatomic build which enables the absorption of moisture in the form of water vapour from the surroundings, together with pollutants found in the air.
- in forest ecosystems we rarely deal with the so-called lichen-free zones, hence lichens occurring in permanent sites can be used for the purposes of air pollution assessment. Then, growth or decrease in the thallus area points to the sanitary condition of atmospheric air, simultaneously defining the biotope conditions.
- for assessing the extent of air pollution, mostly with regard to heavy metals in forest ecosystems exposed to ambient concentrations, lichens transplanted from low-pollution areas can be used.