112
the IHI index are often inversely proportional to the IAP values, so the points of
research where the IHI values are high are often characterized by low IAP values
and vice versa. Values of index of anthropogenic impact (index of human impact,
IHI) are calculated for each point of research individually. Natural areas which are
undisturbed ecosystems like protected natural assets, where it is not necessary to
calculate IHI values, may be exceptions. Gombert et al. (2004) indicate that IHI
values aim to characterize each point of research using the following environmental
parameters: degree of urbanization (U, Urbanization), traffic intensity (T, Traffic),
local development (D, Local developments), and exposure (E, Exposure). Categories
1 to 4 are assigned to each parameter to represent the gradient of alternations.
4.4 Study Area and Sampling Procedure
The research of air quality indication is conducted by field work which includes the
collection of data on the presence and frequency of lichens at predefined points of
research. The number of investigated points varies depending on the size, type, and
conditions of the area under investigation. Each investigated point consists of several substrate units, usually five. Substrate units consist of an organic base, i.e., the
bark of various plant species in forests, tree lines, parks, orchards, and other green
areas. The research includes the analysis of the presence and frequency of epiphytic
(lignicolous and corticolous) lichens.
The method of lichen indication of air quality using lichen as a bioindicator first
involves the identification of lichen, usually done on the spot, and only small parts
of the thallus of those types of lichen that require more detailed tests and whose
identification could not be done on the spot are collected. Numerous and different
determinants in the form of textual guides are available for the identification of
lichens, which are based on the dichotomy of the appropriate or inappropriate
expression, the so-called identification keys like Wirth (1995) and Dobson (2005).
Appropriate tools (e.g., a knife or a geological hammer) are used to collect samples in the field, since the collected lichen samples are found on the bark of plant
species and are sometimes firmly attached to the substrate. The standard procedure
further assumes that the samples are packed in appropriate packaging, on which
ordinal numbers are recorded. These same ordinal numbers are entered into the field
diary as all other relevant data.
Determining the important, morphological and anatomical, character of lichens
is done with the help of a laboratory magnifying glass or light microscope. For the
determination of different types of lichens, it is sometimes necessary to treat the
bark or the marrow of two (by all characteristics) similar specimens of lichens with
certain chemical substances – reagents – in order to determine (or make) (according
to the entries from the determinant) the difference between the analyzed, similar
specimens, on the basis of a qualitative or quantitative difference in the reaction to
the reagent used. Dyed chemical reactions with the following compounds –
S. Ristić et al.
the IHI index are often inversely proportional to the IAP values, so the points of
research where the IHI values are high are often characterized by low IAP values
and vice versa. Values of index of anthropogenic impact (index of human impact,
IHI) are calculated for each point of research individually. Natural areas which are
undisturbed ecosystems like protected natural assets, where it is not necessary to
calculate IHI values, may be exceptions. Gombert et al. (2004) indicate that IHI
values aim to characterize each point of research using the following environmental
parameters: degree of urbanization (U, Urbanization), traffic intensity (T, Traffic),
local development (D, Local developments), and exposure (E, Exposure). Categories
1 to 4 are assigned to each parameter to represent the gradient of alternations.
4.4 Study Area and Sampling Procedure
The research of air quality indication is conducted by field work which includes the
collection of data on the presence and frequency of lichens at predefined points of
research. The number of investigated points varies depending on the size, type, and
conditions of the area under investigation. Each investigated point consists of several substrate units, usually five. Substrate units consist of an organic base, i.e., the
bark of various plant species in forests, tree lines, parks, orchards, and other green
areas. The research includes the analysis of the presence and frequency of epiphytic
(lignicolous and corticolous) lichens.
The method of lichen indication of air quality using lichen as a bioindicator first
involves the identification of lichen, usually done on the spot, and only small parts
of the thallus of those types of lichen that require more detailed tests and whose
identification could not be done on the spot are collected. Numerous and different
determinants in the form of textual guides are available for the identification of
lichens, which are based on the dichotomy of the appropriate or inappropriate
expression, the so-called identification keys like Wirth (1995) and Dobson (2005).
Appropriate tools (e.g., a knife or a geological hammer) are used to collect samples in the field, since the collected lichen samples are found on the bark of plant
species and are sometimes firmly attached to the substrate. The standard procedure
further assumes that the samples are packed in appropriate packaging, on which
ordinal numbers are recorded. These same ordinal numbers are entered into the field
diary as all other relevant data.
Determining the important, morphological and anatomical, character of lichens
is done with the help of a laboratory magnifying glass or light microscope. For the
determination of different types of lichens, it is sometimes necessary to treat the
bark or the marrow of two (by all characteristics) similar specimens of lichens with
certain chemical substances – reagents – in order to determine (or make) (according
to the entries from the determinant) the difference between the analyzed, similar
specimens, on the basis of a qualitative or quantitative difference in the reaction to
the reagent used. Dyed chemical reactions with the following compounds –
S. Ristić et al.