Fascinating Lichens of Sri Lanka

38 Fascinating Lichens of Sri Lanka
The importance of very old trees that host many extremely specialized lichen
species must not be underestimated. These old trees can be found in cardamom
and tea plantations, botanical gardens, parks, and home gardens. Also, it is
essential to maintain a continuous, stable, unbroken canopy which shields the
interior of the vegetation from the vagaries of the climate and from invasion by
adventive weedy species.
Lichen research carried out in Sri Lanka has proved that fragmentation of forests
into small, isolated stands has had a deleterious effect on the lichen flora.
Fragmentation results in a general drying-out of the site due to its small size.
This leads to the establishment of ‘weedy’ non-forest lichen species from nearby
vegetation. So the native epiphytic forest lichens completely lose their habitat
or lose their reproductive ability. The end result is the swamping away of native
lichen forest flora by opportunistic species from outside. Once vanished, the
chances of forest epiphytic lichens re-invading the site are reduced due to the
increased distance from other forests which could serve as a source of lichen
spores.
Many areas with a high conservation value for flowering plants may also
have a high value for lichens and bryophytes, but the reverse is not always
true. Grasslands and rocky areas with no conservation value when it comes
to flowering plants may still be rich in lichens. The lack of awareness on the
environmental importance of lichens means that such areas could be overlooked
during conservation assessments.
There is much more to learn about Sri Lankan lichens—their diversity, biology
and ecology. The knowledge of lichens in the wet zone, intermediate zone,
dry zone, arid zone and in aquatic habitats (both freshwater and marine)
is lacking. Conservationists often lack information on lichens in prioritizing
conservation decisions. Moreover, lichens can be discovered in unexplored
locations as these areas may harbour many new species. As rapid development
is causing a massive loss to biodiversity in Sri Lanka, it is crucial to document
our fascinating lichens before they disappear. It is critical that we document our
threatened lichens on the National Red list and take necessary actions to protect
both lichens and their sensitive microhabitats. It is worth questioning whether
lichen conservation can become a reality in Sri Lanka.
3.2 Studying, Collecting and Identifying
Unlike birds, butterflies, seasonal flowers or many other organisms, there are
no special times of year to observe lichens. The only limiting factor may be
accessibility to a specific habitat. Hundreds of lichen species are accessible and
remain relatively unchanged at any time of the year. You can enjoy lichens in
their natural habitats.
There are many lichens just sitting in your back yard which you may have
never noticed.
Although professional lichenologists insist on collections for identification in
the lab for scientific purposes, most of us will never have the need to collect
lichens. Leave them right where they grow best and enjoy them. Close
up photography and sketching will help produce tangible memories of your
experience.
Never collect lichens from protected areas without a permit. Also do not collect
these slow growing organisms, unless you need them for a scientific purpose.
A hand lens is the single most important tool to have with you (10X jewellers
lens), which will make it easy to see most of the obvious characteristics of
lichens. Most of the macrolichens can be told apart by their general appearance.
The macrolichens included in this book are very easy to identify, just by using a
hand lens in the natural habitats. However, a majority of microlichens, especially
crustoses can only be identified through the careful study of their microscopic
characteristics, the number and type of spores, detail of the ascus structure, and
so forth. Every so often, thin-layer chromatography (TLC) is needed to identify
the lichen compounds more thoroughly.
You need to pay close attention when you collect for scientific purposes. It will
leave a scar when gathering crustose species, as it can only be collected by
removing some of the substrate. This can only be done by using a knife or a
chisel. To obtain lichens found on rocks, the collector may even need a hammer
and cold chisel. Once collected, specimens should be kept in folded paper
packets (not plastic bags) because lichens need to be kept dry or they will rot.
Even experts often have trouble naming lichens with confidence, because the
range of variation within a species can make it resemble closely related ones.
More and more, lichenologists are using molecular methods and statistical
methods of revealing evolutionary relationships to circumscribe genera and
species. However, none of this should discourage readers who want to try
their hand at serious identification. There are good sources of help beyond this
primary guide book for anyone who wants to dig deeper. Access to a good
dissecting tool, a compound microscope, and few easily obtainable chemicals
can take you to higher level.
Like many other groups of organisms, some lichen species are common while
some species are rare to very rare. Currently there is no organization or institution
that is working to identify extremely uncommon or endangered lichens species
in Sri Lanka. Furthermore, the true evolutionary relationships among species of
lichen fungi are just beginning to be worked out, so the classification of lichen
Fascinating Lichens of Sri Lanka 39