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types of environments (i.e. aquatic and terrestrial), using all major taxonomic
groups. However, not all biological processes, species or communities can serve as
successful bioindicators. Physical, chemical and biological factors (e.g. substrate,
light, temperature, competition) vary among environments (Fernandez et al.
2007, 2012).
In common usage, the terms “biomonitoring” and “bioindication” are interchangeable. However, in the scientific community, these terms have more specific
meanings (Fränzle 2006). Bioindicators qualitatively assess biotic responses to
environmental stress, while biomonitors quantitatively determine a response.
Hereafter, the term “bioindicator” is used as a collective term to refer to all terms
relating to the detection of biotic responses to environmental stress. Within this
framework, there are three main functions of bioindicators: (1) to monitor the environment (physical and/or chemical changes), (2) to monitor ecological processes
and (3) to monitor biodiversity (Onianwa 2001).
Examples of environmental, ecological and biodiversity indicators can be found
in many different organisms inhabiting many different environments. Lichens (a
symbiosis among fungi, algae and/or cyanobacteria) and bryophytes (mosses and
liverworts) are often used to assess air pollution. Bryophytes serve as effective bioindicators of air quality because they have no roots and no cuticle and acquire all
their nutrients from direct exposure to the atmosphere (Wolterbeek 2002). Their
high surface area to volume ratio further encourages the interception and accumulation of contaminants from the air. The numerous benefits of bioindicators have
spurred legislative mandates for their use in countries’ monitoring programmes
around the world. Yet bioindicators are not without their problems. Like the canaries
in the coal mine, we rely upon the sensitivity of some bioindicators to function as
early warning signals. In some instances, we cannot discriminate natural variability
from changes due to human impacts, thus limiting the applicability of bioindicators
in heterogeneous environments as Ceburnis and Valiulis report (1999). Accordingly,
populations of indicator species may be influenced by factors other than the disturbance or stress (e.g. disease, parasitism, competition, predation), complicating our
picture of the causal mechanisms of change. A second criticism of the use of bioindicators is that their indicator ability is scale-dependent. For example, a large vertebrate indicator (e.g. a fish) may fail to indicate the biodiversity of the local insect
community. Third, bioindicator species invariably have differing habitat requirements than other species in their ecosystem. Managing an ecosystem according to
the habitat requirements of a particular bioindicator may fail to protect rare species
with different requirements. Finally, the overall objective of bioindicators is to use
a single species, or a small group of species, to assess the quality of an environment
and how it changes over time, but this can represent a gross oversimplification of a
complex system.
Like all management tools, it must be conscious of its flaws. However, the limitations of bioindicators are clearly overshadowed by their benefits. Bioindicators can
be employed at a range of scales, from the cellular to the ecosystem level, to evaluate the health of a particular ecosystem. Bioindicators bring together information
3 Moss Biomonitoring of Air Pollution Around the Coal Mine and Bitol…
types of environments (i.e. aquatic and terrestrial), using all major taxonomic
groups. However, not all biological processes, species or communities can serve as
successful bioindicators. Physical, chemical and biological factors (e.g. substrate,
light, temperature, competition) vary among environments (Fernandez et al.
2007, 2012).
In common usage, the terms “biomonitoring” and “bioindication” are interchangeable. However, in the scientific community, these terms have more specific
meanings (Fränzle 2006). Bioindicators qualitatively assess biotic responses to
environmental stress, while biomonitors quantitatively determine a response.
Hereafter, the term “bioindicator” is used as a collective term to refer to all terms
relating to the detection of biotic responses to environmental stress. Within this
framework, there are three main functions of bioindicators: (1) to monitor the environment (physical and/or chemical changes), (2) to monitor ecological processes
and (3) to monitor biodiversity (Onianwa 2001).
Examples of environmental, ecological and biodiversity indicators can be found
in many different organisms inhabiting many different environments. Lichens (a
symbiosis among fungi, algae and/or cyanobacteria) and bryophytes (mosses and
liverworts) are often used to assess air pollution. Bryophytes serve as effective bioindicators of air quality because they have no roots and no cuticle and acquire all
their nutrients from direct exposure to the atmosphere (Wolterbeek 2002). Their
high surface area to volume ratio further encourages the interception and accumulation of contaminants from the air. The numerous benefits of bioindicators have
spurred legislative mandates for their use in countries’ monitoring programmes
around the world. Yet bioindicators are not without their problems. Like the canaries
in the coal mine, we rely upon the sensitivity of some bioindicators to function as
early warning signals. In some instances, we cannot discriminate natural variability
from changes due to human impacts, thus limiting the applicability of bioindicators
in heterogeneous environments as Ceburnis and Valiulis report (1999). Accordingly,
populations of indicator species may be influenced by factors other than the disturbance or stress (e.g. disease, parasitism, competition, predation), complicating our
picture of the causal mechanisms of change. A second criticism of the use of bioindicators is that their indicator ability is scale-dependent. For example, a large vertebrate indicator (e.g. a fish) may fail to indicate the biodiversity of the local insect
community. Third, bioindicator species invariably have differing habitat requirements than other species in their ecosystem. Managing an ecosystem according to
the habitat requirements of a particular bioindicator may fail to protect rare species
with different requirements. Finally, the overall objective of bioindicators is to use
a single species, or a small group of species, to assess the quality of an environment
and how it changes over time, but this can represent a gross oversimplification of a
complex system.
Like all management tools, it must be conscious of its flaws. However, the limitations of bioindicators are clearly overshadowed by their benefits. Bioindicators can
be employed at a range of scales, from the cellular to the ecosystem level, to evaluate the health of a particular ecosystem. Bioindicators bring together information
3 Moss Biomonitoring of Air Pollution Around the Coal Mine and Bitol…