The Inimitable Lichen
By Ama H. Vanniarachchy
“Nature doesn’t need people - people need nature; nature would survive the extinction of the human being and go on just fine, but human culture, human beings, cannot survive without nature.” –Harrison Ford Biodiversity is the variety of species living on earth. Without the vast number of plants, creatures and microorganisms, life on earth wouldn’t exist.
Biodiversity is essential to the prosperity of the planet. Every species, no matter what their size is, is significant to maintain the balance and existence of the planet. They depend on each other and support each other. Biodiversity gives oxygen, nutrients, clean air, water, helps in pest control, contributes in wastewater treatment, fights pollution, protects soil, fights climate change, gives us food, presents raw materials, and provides medicine. Our economies and cultures largely depend on biodiversity. They nourish us. Inspire us. Gives us energy. In a nutshell, our survival solely depends on biodiversity.
Hence, biodiversity loss is a great threat. Deforestation, overpopulation, climate change and pollution are the major causes of biodiversity loss. The loss of biodiversity is occurring at a high speed since recent times, as has never been witnessed in recorded history. It is reported that more than one million species are on track towards extinction by 2050. The drop of biodiversity which is happening drastically across the globe is catastrophic.
Loss of biodiversity in Sri Lanka
Focusing our attention on Sri Lanka, scientists say that we are home to a large number of plant and animal species, making our little island a place which has a dense biodiversity. Although we can be proud of it, the way we treat our biodiversity is indeed, questionable. Scientist and Senior Lecturer of the Rajarata University of Sri Lanka, Dr. Kanishka Ukuwela, expressing his views on loss of biodiversity in Sri Lanka, said that Sri Lanka’s biodiversity is facing numerous and serious threats.
He stated that in Sri Lanka 40 per cent of our floral plant species, 58 per cent of mammals, 13 per cent of birds, and 60 per cent of amphibians are facing threats of extinction. Eighteen Amphibian species have already gone extinct in Sri Lanka. He further stated that 57 per cent of reptiles, 55 per cent of dragonflies and 47 per cent of inland fish species are under the threat of extinction. According to Dr. Ukuwela, 70 per cent of our ecosystems are destroyed and we only have around 22 – 25 per cent of forest lands remaining. We have cleared more than 1,500 hectares of forests per year.
Thereby, as the forest lands owned by the State were handed over to the regional offices recently, these vital forest lands are now under grave threat of being cleared. He further explained that the mass ecosystem damage in Sri Lanka started during the 1880s when the British started commercial crops by deforesting the hill country. We are now paying the price for this massive damage. Not learning a lesson from that we happily continued with damaging nature and during the time between 1990 and 2000, clearing 26,000 hectares of forest lands per year.
Biodiversity of Sri Lanka
Dr. Ukuwela explained what is meant by biodiversity. He said that biodiversity is the diversity of all species living on earth and that diversity can be explained under three categories.
1. Diversity of species
2. Diversity of DNA
3. Diversity of ecosystems (natural and manmade) According to Dr. Ukuwela, Sri Lanka is home to a large number of endemic flora and fauna. He presented a few statistics about endemic species of flora and fauna. Sri Lanka is home to:
• 930 endemic flowering plant species
• 33 endemic mammal species
• 105 endemic amphibian species
• 150 endemic reptile species
• 56 endemic inland water fish species
• 34 endemic birds species
• 26 endemic butterfly species As Sri Lanka is home to six forest ecosystems and within a small distance one can experience a large variation of these, our ecosystems and biodiversity is unique and rich, explained Dr. Ukuwela. He also said that research about the DNA diversity of animal species of Sri Lanka has not been conducted in the past due to low technical knowledge and resources. However, now, things are changing and research is being conducted, which is a positive trend. Talking about the biodiversity of Sri Lanka, Dr. Gothamie Weerakoon joined to share her experiences and knowledge. She is a botanist, lichenologist and environmentalist, currently employed at the Natural History Museum in London.
Biodiversity and the vital role of rainforests
She explained that 90 per cent of our endemic plant species and more than 75 per cent of our endemic animal species thrive in rain forests. Thus, lies the vital role of rainforests such as Sinharaja in maintaining biodiversity. Sinharaja is home to a vast number of endemic and other species including plants, animals, and microorganisms.
Hence, to clear such a sensitive and complex ecosystem in the name of modern development is not wise and shouldn’t be done at any cost. This is not ‘sustainable development’. Talking about sustainable development, Dr. Weerakoon drew attention to lichens and how they can immensely contribute to the sustainable development of the country. This is one aspect of our ecosystem that we rarely pay attention to.
What are lichens?
Lichens are algae or cyanobacteria or fungi, living together as a small ecosystem, explained Dr. Weerakoon. It is two organisms functioning as a single unit that is an algae and a fungi. A fungi living in a symbiotic relationship with a single-cell photosynthetic organism (algae or a cyanobacterium or sometimes with both).
They are miniature ecosystems. They are selfsustained. Lichens grow on trees, rock, walls, and on soil. Although the number of lichens in Sri Lanka has not been clarified, she said that they assume a total of 3,000 – 4,000 lichen species must be existing in Sri Lanka. There are names of 876 lichens included in the 2020 National Red List book of Sri Lanka (this is yet to be published).
Significance of lichens
Speaking about the vital role of these miniature ecosystems, Dr.Weerakoon said that in some parts of the world lichens are consumed as food by humans. Not only do they provide food, habitat and shelter for other organisms, they also act as ‘pioneer species’ as they contribute in breaking rocks through the acids they produce once they start colonising on rocks. This process forms soil. Nutrient cycling is another importance of lichens.
This is the process of producing nitrogen and making them available for plants. Environmental monitoring is another important role of lichens. As they have different tolerance levels to air quality, scientists can measure the air quality based on the growth of lichens. Lichens do not grow in polluted areas as they are sensitive to air pollution. Hence, they act as a biological indicator of air quality. Lichens also convert carbon dioxide into oxygen during the process of photosynthesis. Scientists also say that they absorb everything in the air, which helps in purifying the air. Heavy metals or carbon or sulphur or other pollutants are absorbed into the lichen thallus.
Lichen research in Sri Lanka
Dr. Weerakoon also said that research about lichens is still in a primitive stage in Sri Lanka. It was in 1867 for the first time that botanist G.H.K. Thwaites collected lichen specimens from Sri Lanka and conducted a study about them. Until the year 1997 only foreign scientists conducted research and studies about lichens in Sri Lanka and exhibited specimens in foreign herbariums. Later in 1999 Sri Lankan scientists focused their research on lichens.
It was Prof. Veranja Karunaratne and Prof. Siril Wijesundara of the University of Peradeniya who were pioneers of lichen research in Sri Lanka. Since then the universities of Sri Jayewardenepura, Sabaragamuwa, Kelaniya, Ruhuna, and Colombo have been involved in lichen research. The National Institute of Fundamental Studies (NIFS), Kandy also conducts research on lichens.
Lichens and sustainable development
As we have stated the importance and the role of lichens in preserving biodiversity, they can also be valuable contributors to the country’s sustainable development. Dr. Weerakoon stated how lichens can be utilised in many industries. She explained that lichens are valuable food sources in some parts of the world such as in North America, Siberia, Korea, and Japan. These foods are rich in nutrition. Apart from food the extracts and chemical compounds in lichens are used as dyes (to dye litmus paper and tweed fabric), perfume, deodorant, sunscreens and toothpastes.
These extracts are also used to produce mild antibiotics. However, the situation in Sri Lanka is not close to the global situation. Although Sri Lanka is home to a vast number of lichens, we hardly utilise them in the process of sustainable development. Dr. Weerakoon said that the University of Kelaniya conducted research on lichens that grow among mangroves and revealed that the extracts can be used to produce anti-cancer, anti-bacterial, and anti-inflammatory medicines.
This makes lichens an immensely useful resource for the pharmaceutical industry. She further said that the chemical compounds in lichens can be used to invent new vaccinations and cures for various new diseases caused by bacteria and viruses. Apart from its medicinal values, Dr. Weerakoon also said that these chemical compounds can be used in many other industries too. After conducting thorough research about the chemical compounds in lichens, it is important to learn how to synthetically manufacture those chemical compounds as we do not want to harm the natural growth of the lichens, said Dr. Weerakoon.
Strong laws to stop gene theft
Dr. Weerakoon also expressed her views about the process of gene theft or DNA theft. As the biodiversity of Sri Lanka is high, we could be the target of many. Hence, we should have strong laws to safeguard our biodiversity from such thefts. Hence, when collaborative research is done with foreign scientists, we have to be very cautious. “As we encroach on nature and deplete vital habitats, increasing numbers of species are at risk. That includes humanity and the future we want.” –UN Secretary-General António Guterres (These views were shared by Dr. Kanishka Ukuwela and Dr. Gothamie Weerakoon at a webinar held on World Biodiversity Day – 22 May. This online event was organised by the Hashtag Generation.)