2.3.8 Bryophytes as environmental indicators
Many bryophyte species are very sensitive to certain environmental conditions – both naturally occurring and imposed by anthropogenic activity. Bryophytes are used as indicators and we distinguish between bioindication and biomonitoring.
Bioindication involves a qualitative response recording species presence or absence. E.g. acidic contamination on Svalbard was identified by the presence of Mielichhoferia elongata (Støvern 2009). Likewise certain liverworts, such as Sauteria alpina and Pressia quadrata and mosses like Ditricum flexicaule and Distichium inclinatum are only found on calcareous substrate such as dolomite, limestone and green schist (Elvebakk 1982). Anthelia juratzkana is a typical indicator of late snow-beds or short growing seasons, as well as acidic substrate like Tertiary sandstone and granitic base rock.
In biomonitoring, quantitative responses are recorded. Bryophytes leaves and thallus lack a cuticle and tissues are easily permeable to water solutions. They tend to absorb and accumulate metals, pollution and mineral dissolved in rain and ground water, and for this reason, many bryophytes are useful for biomonitoring. Bryophytes with a circumpolar distribution are used for measuring atmospheric pollution loads, typically involving heavy metal elements as Pb, Cu, Ni, and Zn, using species such as Hylocomium splendens, Pleurozium schreberi, Sanionia uncinata and Racomitrium lanuginosum (Grodzinska and Godzik 1991, Steinnes and Jacobsen 1994). Results from these studies show that heavy metal concentrations differ significantly from site to site, depending on geological and climatic conditions, and that the pattern of local sources of emission heavily influences metal measurements. Trends in high arctic moss data on heavy metal concentration indicate a decrease in concentrations the last three decades, corresponding to environmental proxies such as glacial ice cores, lake sediments, and atmospheric aerosols (Wilkie and La Farge 2011).