Alien Invaders – II

This one, it is said, came in a pot as an ornamental plant for the Calcutta Botanical garden in 1809. No sooner had the species docked in India it somehow sensed a cosmic opportunity and began to multiply – like mad. The genus Lantana has about a 150 species and is native to the American tropics. Like Congress grass here is another alien from Mexico and surrounds. And this one is possibly the most successful plant invader, having in a fraction of the period of Colonial history, conquered far bigger ‘Empires’ in the Asia-Pacific and Australian realms than the British, the Dutch, the French and the Portuguese put together!  Lantana figures in the list of 100 top Invasive Alien Species (IAS) in the world.

Lantana camara L
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(Locally known as Panjphulli, Ukkal buti in Himachal)

What is it that makes the success of this alien invader so incredibly spectacular? For one, Lantana is loved by birds (the most efficient seed dispersers) and avoided by herbivores (being poisonous), which greatly helps in it being left alone to seed, spread and multiply virtually unhindered. Apparently, butterflies and thrips (tiny winged insects of Greek origin) too have ‘fallen’ for this tropical American making the species indulge in wanton sexual reproduction on an Olympian scale.

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The Impact

Around 2009-10 it was estimated that over one lakh hectares are infested with Lantana in Himachal. Open areas not only in forests but in villages and towns too have been blanketed by Lantana.  And the infestation is spreading.  The rate of spread is anybody’s guess, but those who walk would have noticed that Lantana can now be seen under plantations and many open Chir forests have clumps of this weed merrily coming up.  Old khair plantations seem to be the worst affected. Lantana is giving Congress grass a run for its money, having gone a lot wilder than the latter.

Lantana shrubs are dense and prickly, bruising hands and tearing clothes of those who try to cut them. Decades ago, when timber was floated down the Sutlej, from Kinnaur to Bilaspur during winter, lantana patches along the river and around nearby villages came in handy to hide the stolen sleepers and later retrieve them at leisure, once the forest guards protecting the “ghall” had moved on. This was in 1979-80. Soon after, hunting was banned in Himachal and this apparently led to a wild boar boom. Meantime, lantana had consolidated its hold on encroached land (much like many orchardists) with dense, virtually impenetrable thickets. These became ideal ‘habitat’ for wild boars which could raid farmer’s crops at will and then take shelter in the lantana thickets. This problem I am told persists and has grown in recent years.

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      In deep moist soils Lantana blooms round the year

As the world warms up and temperatures climb, a dogged invader like Lantana is poised to make inroads into temperate areas. For Himachal and its temperate forests that could be disastrous.  Loss of pasture, grasslands, native flora, domestic and wild animals and of course the economy would have to take a big hit. Worryingly, with rising summer temperatures, Lantana infested areas become a tinder box. Massive forest fires in such areas seem imminent.

What good is Lantana?

Because Lantana is a woody shrub and a fairly big one, its biomass is good for making charcoal, though of low calorific value.  However, when mixed with charcoal of say Kikar (Acacia nilotica) and with char of pine needles, good enough fuel briquettes can be made.  A little research and experimenting could easily trigger a promising off farm income opportunity, especially for poorer, rural women.  In predominant Chir pine areas the threat of forest fires could simultaneously be lowered.  Unfortunately, government is reluctant or miserly in promoting such ventures in a practical way.

The great mass of leaves and flowers of Lantana, if they can be harvested economically, could become a good source of raw material for vermi-composting. Tribal groups in South India have ventured to make Lantana furniture (as have NGOs in other states) with some success. The wood is strong and anti-termite and when varnished looks good.  Apparently, research reveals that extracts from Lantana yield effective fungicides and pesticides for vegetable crops.

Like Congress Grass, Lantana to is a medicinal plant with various uses for ailments including leprosy and scabies. Ethno-medicinal documentation and research across the world are bringing to light more traditional medical applications of Lantana and leads to develop new medicines.

Lantana invasion around Pong Wildlife Sanctuary (Photo by Devindra Dhadwal)
           Lantana invasion around Pong Wildlife Sanctuary
                         (Photo by Devindra Dhadwal)

Just as Lantana disrupts our ecosystems and therefore our lives and those of our animals, human ingenuity counters this invasion by making the invader useful for our many wants and problems.  In that multi-faceted approach perhaps can be found the answers to tackle this perilous invader.

Nodnat - is a pen name that the writer with deep knowledge of Himalayan flora and fauna and a keen environmentalist has adopted. He hails from Kotgarh, in Shimla Hills and retired as Principal Chief Conservator of Forests from Himachal Pradesh forest department.

3 Comments

  • Any examples of an Indian plant specie traveling overseas? Like to South Africa or the Carrabians where we have a large Indian diaspora?

    • Well Chutki, a lot of the Indian diaspora in the Carribbean and elsewhere are vegetables! But these guys have carried with them, willy-nilly several species, the list of which will take much time to compile. But i’ll send you some interesting ones.

  • Very interesting and informative, Nodnat. I particularly like the term Invasive Alien Species or IAS. It is an amazingly apt acronym for, though the other, better known IAS is an indigenous species, it shares a lot of the qualities of the lantana- very difficult to eradicate, it quickly takes over all lesser species, serves no purpose other than to proliferate mindlessly and provides good cover for all kinds of wild life. It has worked well in tandem with that other weed, Congress( grass) since Independence. Maybe the time has now come for some other species- say, the Backwater Japonica Parthenium or BJP ?

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