14 Jan

Parasitic Plants & Other Special Plants

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Content

• Parasitic Plants
• Carnivorous/ Insectivorous Plants
• NeelKurinji (Strobilanthes kunthianus) -> Monocarpic Plants
• The Living Root Bridge (The Jing Kieng JRI)
• Commonly used Medicinal Plants (AS DETAILED IN NCERT)
• Three Himalayan Medicinal Plant enter IUCN Red List (Dec 2022)
• Arogyapacha (Trichopus zeylanicus)
• Indian Birthwort (Aristolochia Indica L.) – a threatened medicinal plant in Assam
• Largest Plant the world
• Theobroma Cacao
• DragonFruit (Kamalam)
• Rosewood
• Indian Rosewood (Dalbergia Latifolia)
• Red Sanders (Pterocarpus Santalinus)
• Sandalwood
• Mahua (Madhuca Indica)
• Seabuckthorn
• Madhuca Diplostemon (Family Sapotaceae)
• Sonneratia Alba (Mangrove Apple)
• Humboldt’s Enigma

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1. PARASITIC PLANTS

• Gleadovia Konyakianorum
  • ­A Parasitic plant discovered in Nagaland recently. It is a holoparasite (i.e. complete parasite) as it derives all its food from the host.
  • It has no chlorophyll of its own and survives by feeding on another species of plant that has chlorophyll.
  • ­It has been named in the honour of Konyak tribe of Nagaland. ­       Conservation Status: Data deficient.
• Orabanche Cernua (Broomrape or Broom-rape): A parasitic weed that is affecting tobacco cultivation
  • Introduction :
    • Orobanche is a genus of over 200 species of parasitic herbaceous plants in the family Orobanchaceae, mostly native to the temperate Northern Hemisphere.
    • These plants completely lack chlorophyll, bearing yellow, white or blue snapdragon like flower.
    • As they have no chlorophyll, they are totally dependent on other plants for nutrients.
      • Broomrape seeds remain dormant in the soil, often for many years, until stimulated to germinate by certain compounds produced by living plant roots.
    • In India, it is recorded as a ‘principal weed‘. And adversely affects tobacco crops.
    • Globally it affects tomato, eggplant, potato, cabbage, coleus, bell pepper, sunflower, celery and beans.
• Some other details about Parasitic Plants
  • Plant parasites are differentiated as stem and root parasites.
    • Common stem parasites found in India are
      • Loranthus sp, on Mango trees, and Cuscuta reflexa, a climber.
    • Among the root parasites are
      • Sapria himalayana, a rare holoparasitic flowering plant found in Arunachal Pradesh and Meghalaya

2. CARNIVOROUS/ INSECTIVOROUS PLANTS

• Introduction
  • Carnivorous plants are those plants which derive some or most of their nutrients (but not energy) from trapping and consuming animals or protozoans, typically insects and other arthropods. Insects are the most common prey for these plants and therefore they are also sometimes called insectivorous plants.
  • These plants have adapted to grow in areas which lack nutrients like swamps and rocky areas. The plants receive these nutrients, especially nitrogen from their preys.
  • They extract water and some minerals from soils too.
  • Remember: They have chlorophyll and they do photosynthesis to convert sun’s energy into carbohydrate.
• Types
  • The plants are divided into active and passive types based on their trapping mechanism.
    • Active insectivorous use movements to trap the insect (ex. Venus fly-trap, Utricularia)
      • They use trapping mechanism like leaf traps etc
    • Passive insectivorous depend on long tubes with hairs that trap prey.
      • They use pitfall mechanism having some kind of jar or pitcher-like structure.
• ­Insectivorous Plants in India
  • Insectivorous plants in India are naturally found in Sikkim, Arunachal Pradesh, West Bengal and the Garhwal Himalayas.
  • The important genus of carnivorous plants in India are:
• Nepenthes
  • These are the most glorious and spectacular genus of carnivorous plants in India.
  • These plants form wonderful pitchers and their carnivorous traps are hungry looking maws that look every bit dangerous.
  • It relies on pool of water to trap its prey by a combination of decaying odours and sometimes a red coloration. Once inside the picture, the prey fails to get a grip on the interior walls of this carnivorous plant because of the flaky wax on them, falls into water and hence is digested.
  • Unlike other carnivorous plants, besides insects, gnaws and flies they feed on mice and frogs too.
  • E.g.
    • Nepenthes Khasiana (Indian Pitcher Plant)
    • https://youtu.be/1CP1i0UKvb8?t=144
• Pinguicula
  • Also known as Butterworts, and are mostly grown for their pretty orchid like flowers.
  • The leaves of these plants emit a faintly fungal scent that attracts prey which gets stuck to the glandular surface of the leaves which then drowns in the moist pool of slime and is indeed digested.
  • They are absent in India.
  • https://youtu.be/teLkmlaDSVU
• Drosera
  • Drosera is a sticky flypaper Carnivorous plant that bears long tentacles on its leaves. These stalks are tipped with brightly colored glands.
  • As soon as an insect lands on these leaves, it sticks to them and these leaves coil around their prey to slowly digest it.
  • There are around 180 species of these plants found globally. They are mostly found in region which are poor in organic nitrogen and phosphorus. (e.g. bogs on sandy banks or other mineral soils that are poor in organic nitrogen and phosphorus)
  • https://www.youtube.com/watch?v=h9NnctZVrvk
• Utricularia
  • largest genus of carnivorous plant that one can find, with more than 200 species occurring globally. It is a plant festooned with utricles or little bag like bladders and thus is named Utricularia. The little bladders in these plants are actually the carnivorous traps or the suction traps.
  • The flowers of these plants are very small with a wild & varied display of Colors and form.
    • They mostly prey on worms, frogs, mosquitoes, scuds, flies, fleas and even amoeba.
  • Conservation Status
    • The endangered species of carnivorous plants in India are Drosera Peltata, Aldrovenda vesiculosa and Nepenthese Khasiana have been included in the Red Book as endangered plants.
  • Main threats faced
    • Gardening trading for medicinal properties
    • Habitat destruction
    • Pollution

3. OTHER SPECIAL PLANTS

1) NEELKURINJI (STROBILANTHES KUNTHIANUS) -> MONOCARPIC PLANTS

• About Neelakurinji
  • It is a shrub found in Shola forests of Western Ghats in South India. Niligiri Hills, which literally means the blue mountains, got their names from the purplish blue flowers of Neelkurinji that blossoms every 12 years.
  • The shrub has been documented to bloom in 1838, 1850, 1862, 1874, 1886, 1898, 1910, 1922, 1934, 1946, 1958, 1970, 1982, 1994, 2006, and 2018.
• Why Neelakurinji flowers only once in 12 years?
  • Some perennial flower only once in lifetime, set seeds and die. The next generation of plants is established from these seeds and the cycle in repeated. Such plants are known as monocarpic, opposed to polycarpic plants that flower and set seeds many times during its lifetime. They flower only after attaining maturity. The time taken for attaining maturity may differ for different species. This is 12 years for Neelakurinji.
  • Another characteristic shown by monocarpic plants is that it flowers gregariously in a single season. The term “Plietesials’ is used to refer to such plants.
• Other example of Monocarpic Plants
  • Bamboos are monocarpic plants which take around 40 years to mature and flower

2) THE LIVING ROOT BRIDGE (THE JING KIENG JRI)

• More details about the living root bridges
  • The Jing kieng jri or living root bridges are aerial bridges built by weaving and manipulating the roots of Indian rubber tree (Ficus Elastica). They have been serving as connectors for generations in Meghalaya for Khasi and Jaintia people. Some root bridges have also been observed in Nagaland.
  • These bridges have been built over many centuries and are a primary means to cross streams and rivers. The span distances between 15-250 feet and have also become a source of tourist attraction.

• • The root bridge uses traditional tribal knowledge to train the roots of Indian Rubber Fig Tree, found in abundance in the area, to grow laterally across the stream bed, resulting in a living bridge of roots.
  • The process begins with placing of young pliable aerial roots growing from Ficus Elastica trees in hollowed out areca catechu or bamboo trunks. These provide the essential nutrition and protection from weather, and also perform as aerial root guidance system. Over time, the aerial roots increase in strength and thickness, and the support bamboo trunks are no longer needed.
  • The nature of Ficus Elastica makes its conducive to the growth of bridges because of its very nature. They are elastic, the roots easily combine, and plants grow in rough, rocky soils. Further, they become stronger with time and are self-repairing in nature.
  • Experts consider these living root bridges as an example of indigenous climate resilience.
• Research in its application in modern architecture (2019)
  • Researchers from Germany studied 77 bridges in 2015, 2016 and 2017. This study has been published in the journal Scientific Report and suggest that bridges can be considered a reference point for future botanical architecture projects in urban contexts.
• Attempt to get World Heritage Tag for living root bridges (Jan 2022)

4. IMPORTANT MEDICINAL PLANTS IN NEWS

1) COMMONLY USED MEDICINAL PLANTS (AS DETAILED IN NCERT)

MEDICINAL PLANTS

India is known for its herbs and spices from ancient times. Some 2,000 plants have been described in Ayurveda and at least 500 are in regular use. The World Conservation Union’s Red List has named 352 medicinal plants of which 52 are critically threatened and 49 endangered. The commonly used plants in India are:

• Sarpagandha : Used to treat blood pressure; it is found only in India.
• Jamun : The juice from ripe fruit is used to prepare vinegar, which is carminative and diuretic, and has digestive properties. The powder of the seed is used for controlling diabetes.
• Arjun : The fresh juice of leaves is a cure for earache. It is also used to regulate blood pressure.
• Babool : Leaves are used as a cure for eye sores. Its gum is used as a tonic.
• Neem : Has high antibiotic and antibacterial properties.
• Tulsi : Is used to cure cough and cold.
• Kachnar : Is used to cure asthma and ulcers. The buds and roots are good for digestive problems.

Identify more medicinal plants in your area. Which plants are used as medicines by local people to cure some diseases?

Source: Medicinal Plants by Dr. S.K. Jain, 5th edition 1994, National Book Trust of India

2) THREE HIMALAYAN MEDICINAL PLANT ENTER IUCN RED LIST (DEC 2022)

A. Meizotropis Pellita (CR)

Commonly known as Patwa, it is a perennial shrub with restricted distribution in Uttarakhand. The Species has been listed CR based on its limited area of occupancy (less than 10 sq km). Threats: Deforestation, habitat fragmentation and forest fires.

Medicinal Properties: The essential oil extracted from the leaves of the species possesses strong anti-oxidants and can be promising natural substitute for synthetic anti-oxidants in pharmaceutical industries.

B. Dactylorhiza hatagirea (EN)

It is commonly known as Salampanja.

It is perennial tuberous species endemic to the Hindu Kush and Himalayan ranges of Af, India, Nepal, Bhutan and China.

Threats: Habitat loss, livestock grazing, deforestation, and climate change. It is extensively used in Ayurveda, Siddha, Unani and other alternative systems of medicine to cure dysentery, gatritis, chronic fever, cough and stomach ache.

C. Fritilloria cirrhosa (VU)

Also known as Himalayan fritillary is a perennial bulbous herb.

It’s population is estimated to have declined by at least 30% in last 24 years. Considering the rate of decline, long generational length, poor germination potential, high trade value, extensive harvesting pressure and illegal trade, the species is listed as ‘Vulnerable’.

Medicinal Properties: In China, it is used for treating bronchial disorders and pneumonia. It is also a strong cough suppressant and source of expectorant drugs in traditional Chinese medicine.

The Himalayan region is a biodiversity hotspot but there is a lack of data on many species here. The assessment of these plants will set our conservation priorities and help protect the species.

3) AROGYAPACHA (TRICHOPUS ZEYLANICUS)

• More About Arogyapacha
  • Trichopus zeylanicus (Arogyapacha) is a highly potent medicinal plant endemic to the Agasthya hills. It is traditionally used by the Kani Tribal community to combat fatigue.
  • Studies have also proved its varied spectrum of pharmacological properties such as anti-oxidant, aphrodisiac, anti-microbial, anti-inflammatory, immunomodulatory, anti-tumor, anti-ulcer, anti-hyperlipidemic, hepatoprotective, and anti-diabetic.
• Significance of Genome mapping of the plant
  • It will help us get deeper knowledge of plant’s molecular secret. The genetic data will expedite research on Arogyapacha, particularly its secondary metabolism, genetic breeding, and comparative studies.

4) INDIAN BIRTHWORT (ARISTOLOCHIA INDICA L.) – A THREATENED MEDICINAL PLANT IN ASSAM

The population stock of the species has been depleting fast in its natural habitats as a consequence of certain factors such as habitat fragmentation, over-exploitation due to its high medicinal properties, and other anthropogenic activities.

5. PLANTS/ HYBRIDS/ VARIETIES IN NEWS RECENTLY

1) LARGEST PLANT THE WORLD

• Details
  • This plant is Ribbon Weed (or Posidonia australis) and has been discovered in Shark Bay off the West Coast of Australia.
    • The researchers have found that it is 180 km in length and covers 20,000 hectares of area. Its age has been estimated to be 4,500 years.
    • It has double the number of chromosomes than other plants.
  • Over the years, it has managed to survive the volatile atmosphere of the shallow shark Bay.
• Why has been discovered so late when it is so large?
  • The existence of the sea grass was known, but it wasn’t known that it was a single plant.
• How do we know that it’s a single plant?
  • Researchers sampled seagrass shoots from across Shark Bay’s variable environments and generated a ‘fingerprint’ using 18,000 genetic markers. This fingerprint was found to be the same.
• How did it grow and survive for, so long?
  • Around 4,500 years ago, the plant took root in the Shark Bay. Then it kept spreading through it rhizomes overcoming everything in its way.
  • Ribbon week rhizomes can usually grow to around 35 cm per year, which is how the scientists arrived at its lifespan of 4,500 year.
  • One reason that it has survived for so long is that it is Polypoid – instead of taking half-half genome from both parents, it took 100%, something not unheard of in plants. Therefore, this ribbon weed has twice the number of chromosomes other plants of the same variety has. Polypoid plants often reside in places with extreme environmental conditions, are often sterile, but can continue to grow if left undisturbed, and this giant seagrass has done just that.
• Note:
  • The second largest plant known on earth is the clonal colony of a quaking Aspen tree in Utah, which covers 43.6 hectares.
  • The largest tree in India is the Great Banyan in Howrah’s Botanical Garden. It covers 1.41 hectares.

3) THEOBROMA CACAO

• It is also called the Cacao tree and the Cocoa tree. It is a small evergreen tree in the family Malvaceae.
• It’s seeds, the Cocoa beans, are used for making chocolate liquor, cocoa solids, cocoa butter, and chocolate.
  • Cocoa beans are fermented, dried, roasted, and ground to form the chocolate powder. Most chocolate sold today are made from the species Theobroma cacao. But, indigenous people in South America, Central America and Mexico make food, drink and medicine with many other Theobroma species.
• History of Chocolates:
  • The history of chocolates has a compelling and rich story.
  • Cacao was domesticated at least 4,000 years ago, first in Amazon basin and then in Central America.
  • Four thousands of years, Mesoamericans have used Cacoa for many purposes: as a ritual offering, a medicine, and a key ingredient in both special occasion and everyday food and drink – each of which had different name. One of these special, local cacao concoctions was called “chocolat”.
• In 16th century, it was brought toEurope and Africa. Drinking chocolate soon became a way to socialize.
• Advantages:
  • Cacao is one of the most anti-oxidant rich fruit and eating it increases endomorphin, a hormone which makes you calm and happy.

4) DRAGONFRUIT (KAMALAM)

• Scientific name: Hylocereusundatus.
• It is grown in countries such as Malaysia, Thailand, the Phillipines, the USA and Vietnam.
• It is very rich in fiber, vitamins, minerals and anti-oxidants.
• In India, the beginning of Dragon fruit cultivation started in 1990s. In recent years it has become very popular since farmers have taken up the cultivation across various states. It’s cultivation requires less water and can be grown in various kinds of soil.
• There are three main varieties of dragon fruit: white flesh with pink skin, red flesh with pink skin, and white flesh with yellow skin.
• In July 2020, PM Modi in ‘Mann Ki Baat’ had mentioned about Dragon fruit farming in the arid Kutch region of Gujarat.

5) ROSEWOOD

• Rosewood refers to any number of richly hued timber, often brownish with darker veining, but found in many different hues. All genuine rosewood below to genus Dalbergia.
• Pre-eminent rosewood appreciated in the Western World is the wood of Dalbergia nigra. It is best known as ‘Brazilian Rosewood’ or ‘Bahia Rosewood‘. The wood has a strong, sweet smell, which persists for many years, explaining the name rosewood.
• Another classical rosewood come from Dalbergia latifolia (VU), known as (East) Indian rosewood. It is native to India and is also grown in plantations elsewhere in Pakistan.
• Other species
  • Dalbergia sissoo (LC)is a rosewood species from India and Bangladesh, usually known as Sheesham or North-Indian Rosewood.
    • Its timber is extremely dense and has mild rot resistance. It is used for making cabinets and flooring, and for carving. Due to its after work quality when sealed and dyed, it is often sold as genuine rosewood and teak.
• Properties and uses
  • All rosewoods are strong and heavy, taking an excellent polish, being suitable for guitars, marimbas, recorders, handles, furnitures, luxury floorings etc.
• Uses
  • Steep demand in international market for musical instruments and furniture.
• Dalbegia Sisoo (LC)
  • Its timber is extremely dense and has mild rot resistance. It is used for making cabinets and flooring, and for carving. Due to its after work quality when sealed and dyed, it is often sold as genuine rosewood and teak.

6) INDIAN ROSEWOOD (DALBERGIA LATIFOLIA)

• D latifolia is native to India and Indonesia, but is also grown in Nigeria, Kenya, Vietnam, the Phillipines, and other tropical Africa and Asia as an ornamental plant.
• It is very well known for producing very hard and durable wood with a long straight bore, which makes it highly valued on international markets. It’s bark is also used for medicinal purpose in natural ranges.

• IUCN: EN
• CITES: Appendix-II

7) RED SANDERS (PTEROCARPUS SANTALINUS)

• Why in news
  • Red Sanders falls back in IUCN’s ‘endangered’ category (Jan 2022)
    • Why?
      • IUCN assessment stated that “over the last three generations, the species has experienced a population decline of 50-80%. It is assessed as Endangered.
      • The overharvesting of the species has left the population structure skewed, with trees of harvestable size and maturity being scarce and making up less than 5% of the trees remaining in the wild.
      • Illegal international trade has continued – Large volume of Red Sanders timber and products are seized regularly by authorities at all stages of the illegal supply
    • In 2018, IUCN moved it to Near Threatened Category from Endangered earlier.
• About Red Sanders:
  • Red Sander (Pterocarpus Santalinus) or Red Sandalwood or Rakt Chandan, and Saunderwood, are endemic to Southern Eastern Ghat Mountain Ranges of South India (Seshachalam Forests of Andhra). They are found in districts of Chittoor, Kadapa, Nandhyal, Nellore, Prakasam of Andhra Pradesh.
    • These are known for its rich hues and therapeutic properties and are high in demand across Asia, particularly in China and Japan, for use in cosmetics and medicinal products as well as for making furniture, woodcrafts and musical instruments.
      • The rare wavy grain variant is highly valued in Japan for its acoustic properties and is used to make musical instruments.
      • In addition, the timber is also exploited for the extraction of Santalin (a red pigment used as dye and colorant in food), medicine and cosmetics.
    • Its popularity can be gauged from the fact that a tonne of Red Sanders costs anything between Rs 50 lakh to Rs. Crore in international market.
    • Note: this is not aromatic. (it should not be confused with the aromatic Santalum Album (Indian Sandalwood) (VU) tree that grow natively in South India.
      • IUCN: Endangered
      • WPA: Schedule-II
      • CITES: Appendix-II

8) SANDALWOOD

• It is also known as Chandan, Cendana, East Indian Sandalwood, Sandal, Sandal tree, White Indian sandalwood, chandal and Peetchandan.
• Where is it found?
  • S Album, commonly known as Indian Sandalwood, is a dry deciduous forest species native to India, China, Indonesia, Australia and Phillipines. It is also grown in plantation in Australia.
• The small tropical tree grows to 20m in height with red wood and a variety of dark colors of bark (dark brown, reddish and dark grey).
• Applications:
  • Because it is strong and durable – it is mostly harvested for its timber. Sandalwood heartwood, which is close grained, is used for fine furniture and carving.
  • The heartwood and roots also contain ‘Sandal oil’ which is used in perfumes, incenses, cosmetics, soaps, and medicines.
  • The bark contains tannin, which is used for dye.
• Protection:
  • Sandalwood is highly valued in India. Over the years, uncontrolled harvesting have caused populations to dwindle in recent years.
  • To Conserve Sandalwood, India has imposed an export ban on Sandalwood and instated conservation measures to protect the species in the country.
  • IUCN: VU
  • CITES: Not listed

9) MAHUA (MADHUCA INDICA)

• It is an Indian tropical tree found largely in Central, southern and north Indian plains and forests. They are also found in Nepal, Myanmar, and Sri Lanka.
• Uses:
  1. Mahua flowers, fruits, and leaves are edible and used as vegetables in India and other Southern Asian Countries.
     • The sweet, fleshy flower are eaten fresh or dried, powdered and cooked with flour, used as a sweetener or fermented to make alcohol.
  2. It is also an oil plant, whose seeds yield between 35 and 47% oil. This oil is used for making soaps and candles. It also has a potential use in bio diesel production. Though, it is used as edible oil by tribals, WHO recommends against it as it contains aflatoxin, a toxin component. The processing of oil can get rid of aflatoxin and makes it edible.
  3. Cocoa Butter Extender: It is prepared from Mahua seed oil and is a prized product. It can be used for making chocolate and other confectionaries. Experts feel that this product has the scope of altering socio-economic conditions of tribals in India.
  4. Timber: The tree is also used for its hard, strong, dense and reddish timber.
  5. Traditional Medicines also use some mahua components.

10) SEABUCKTHORN

• Details
  • Seabuckthorn is a shrub where an orange-yellow coloured edible berry grows. This plant is found in upper tree line of Himalayan region in India including in the wild in Lahaul, Spiti, and parts of Kinnaur. There are many medicinal, ecological and economic benefits of growing the seabuckthorn plant.
  • Importance of the plant:
    • As folk medicine it is used for the treatment of stomach, heart and skin problems. Some modern scientific research also back these uses.
      • The leaves and fruits of this shrub is rich in carotenoids, omega fatty acids and vitamins. It also help troops in getting accustomed to high altitude.
    • The plant is also a crucial source of fodder and fuelwood. It is also a soil binding plant which means it is capable of preventing soil-erosion.
    • It can also help to preserve floral biodiversity.
      • Due to pest attacks, many willow trees in the Lahaul valley are dying and this small plant can turn out to be a good alternative in order to protect the local ecology.
    • The plant also has commercial value and is utilized for production of jams, juices, as well as nutritional capsules.
  • So,seabuckthorn needs to becultivated on largescaleforit to bea raw material fortheindustry. This can be done on arid and marginal lands with the help of CAMPA funds.
    • MoEF&CC has asked these states to come up with a proposal where they can take up such plantations.
    • This will also reduce water flow from Himalayan glaciers.
    • Following this, the Himachal Pradesh CM has announced that the government will be planting seabuckthorn on 250 hectares of land in the state. This will be done over the next five years.

11) MADHUCA DIPLOSTEMON (FAMILY SAPOTACEAE)

• Why in news?
  • Madhuca Diplostemon, a tree species, long believed to be extinct, has been discovered in Western Ghats after a gap of more than 180 years. (Oct 2020)
• Details
  • This species was last spotted in 1835, when its specimen was first collected. Since its original collection, specimens of Madhuca Diplostemon was never collected again, neither from its locality nor elsewhere, and botanical exploration both in Western and Eastern Ghats failed to locate the species.
  • Recently, it was again discovered from a sacred grove in Kollam district in Western Ghats.
    • This sacred grove is Koonayil Ayiravilli Siva Temple at Paravur, Kollam.
  • Scientists at the Jawaharlal Nehru Tropical Botanical Garden and Research Institute (JNTBGRI) at Palode have identified this species.
  • Only 1 mature species has been found so far, meaning that this rediscovery was extremely valuable from a scientific, environmental and conservation point of view.
  • The species should also be eligible to be categorized as Critically endangered.

12) SONNERATIA ALBA (MANGROVE APPLE)

• Why in news?
  • Sonneratia Alba species declared the state Mangrove tree of Maharashtra.
• Details
  • It is an evergreen mangroves species that grows upto five feet. It has white flowers with pink base and bears distinctive green apples as fruits. The fruit is used for making pickles.
    • They often grow on newly-formed mud flats playing an important role in combating land erosion.
  • Maharashtra is the first coastal state in India to declare a state mangrove tree species to enhance conservation of the salt-tolerant vegetation.
    • Globally, there are around 60 mangrove species. Maharashtra is home to 20 of them.

6. SOME RECENT CURRENT AFFAIRS UPDATE

1) HUMBOLDT’S ENIGMA

• Background: Conventionally, it was understood that biodiversity will be highest around the equator, in tropics, as this region has higher primary productivity as it receives the highest sunlight (energy). As one moves away from equator biodiversity decreases. Tropical rainforests thus hold the crown for species richness.
• Humboldt’s Observation: Alexander von Humboldt, a German naturalist, during his extensive travels through South America in the early 19th century, noticed something intriguing. Mountain ranges, despite occupying relatively small areas compared to vast tropical forests, displayed exceptionally diverse plants and animal life. This stood in stark contrast to the predicted decrease in higher latitudes.
  • Two centuries later, group of bio-geographers – scientists who explore the relationship of diversity with geography – used modern tools to take another look at the drivers of biodiversity. Based on their findings, they proposed their own version of the link between biodiversity and mountains and called it Humboldt’s enigma.
  • Examples of Humboldt’s enigma in India:
    • Eastern Himalayas: These are the second-most diverse area of perching birds in the world. For river birds, the eastern Himalayas may be the most diverse.

• Reasons for the Enigma:
  • Compression of a wide range of ecosystem into relative short distance: Mountains boast diverse landscapes with varied terrain, elevation, and microclimates. This creates a mosaic of distinct habitats, fostering speciation and niche adaptation among organisms.
  • Geological Process like Uplifts, result in new habitats where new species arise, so the habitats are ‘cradles’.
  • Climatic Stability: Some climatologically stable mountains persist there for a long time, so these spots are ‘museum’ that accumulate many such species over time.
    • This provides refuge and protection to species during changing environment and thus aids biodiversity.
  • Unique Resources: Mountains have resources like nutrient rich volcanic soils and unique water regimes which gives sustenance for specialized species.
• E.g.:
  • Coastal Tropical Sky Islands (mountain surrounded by lowlands), like the Shola Sky Islands in the Western Ghats, are good examples of ‘museum’. Here old lineage has persisted on the mountains tops as climates and habitats fluctuated around them in lower elevations. This is the reason, some of the oldest bird species in the western ghats, such as the Sholicola, and the Montecincla, are housed on the Shola Skey Islands.
  • The Northern Andes Range – including Chimborazo – is considered the most biodiverse place in the world. If we start from the foothills of the Andes and climb, we’re going to counter different temperature and rainfall levels that support everything from tropical evergreen biomes in the lower elevation to the alpine and tundra biomes near the top. Such a large variation over short distances supports the immense biodiversity found in mountain regions – and worldwide.