Tuesday, April 21, 2015

Environment: Lichens are Nature's Indicator of Fresh Clean Air


How do we know if we are living in a pristine environment? Consult the lichens in your area.
Dr Abe V Rotor
Squamous lichen, an intermediate of crustose and foliose types. La Mesa Eco Park, QC

A lichen is formed by a alga and a fungus living in symbiosis, which scientists believe to have evolved through millions of years. It is a classical example of evolutionary success through cooperation rather than competition.  The union is so closely knit that they have become strictly inseparable.  The classification of lichens  is based on  species composition, and on their anatomical and morphological characteristics as evidenced by their growing habits.

Lichens are among the longest living organisms.  It is because of their symbiotic advantage over individual organisms. It is a well known fact that a lichen may have a lifespan of several centuries.  In fact a certain Arctic specimen of a crustose lichen, Rhisocarpon geographicum, was found to be about 9000 years old!

If you find lichens growing in the area where you live, you are very lucky. You are away from the black cloud of smog, the confines of "maddening" crowd, smoke belching vehicles, and spewing factory chimneys. And you have all the reasons to be happy - so with your family. This is luxury today.

The air you breath is fresh and clean, cool and soothing. Your lungs are clear, your skin glistens clean and robust, you walk with stride and gait, and you wear a smile even if you are not aware of it. It is because the air that surrounds us is a natural blanket that enwraps our body physically and physiologically, outside and inside, through respiration and circulation.

Thank the lowly lichen - nature's biological indicator.

Foliose lichen in summer. Note large composite mass. Lipa Batangas
Foliose lichen, Parks and Wildlife Nature Center QC. Note the smaller size of this specimen as compared to the foliose lichen in Lipa (above). Lichens may differ not only in structure but by the component members - a lichen being a community of alga and fungus living in mutualism. Generally, as the air becomes polluted the size of a lichen decreases - or may totally disappear.

Fruticose lichen appears like beard. This presence and condition of the fruticose lichen is perhaps the ultimate assurance of good air quality. Tagaytay (Angels Hills Retreat Center)

Community of green algae, lichen and moss (UP Diliman). During the summer months the moss in its sporophytic phase dries up but grows back the following rainy season. This is not the case of lichens.
This mass of lichen grows on cycad (Oliva) growing just across my residence in QC. It is a queer looking kind which does not clearly fall under the general classification of lichens.  It is neither foliose nor fruticose, although it is closer to the latter, except for its tendency to form a compact colony instead of growing freely to form hanging structures for which it earned its name fruticose. The specimen is also different from two other type: Leprose which appear as powdery mass, and Squamulose which is much the same as crustose, but with 
raised edges, which can be folded and lobe-like.

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