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IndiaWilds Newsletter Vol. 3 Issue X

National Action Plan on Invasives: IndiaWilds Newsletter Vol. 3 Issue X

This issue of IndiaWilds Newsletter examines the impact of Invasive species on our bio-diversity. This issue with images is available online.


However, to set the record straight not all exotic species are harmful and some became harmful after passage of many years. Many of our plant species in India owe their origin abroad. According to a FAO report, out of the nearly 45000 (Fortyfive thousand) plant species in India, nearly 18000 (eighteen thousand) of those are exotics which corresponds to a massive 40% (Forty percentage). Only when these species start breeding rapidly colonising large areas by out-competing the local species for food/nutrition, producing allelopathic effects on other plants to inhibit their growth or simply constricting or killing them etc they get categorized as harmful or invasive species.

Any species that is not the native of a particular region is termed as exotic species or aliens. When these exotic species find the conditions suitable for them to start multiplying and dominating the native species, they are termed as Invasive Species or invasives. According to IUCN Invasive alien species are animals, plants or other organisms introduced by man into places out of their natural range of distribution, where they become established and disperse, generating a negative impact on the local ecosystem and species. IUCN acknowledges that invasive species represent the second most significant cause of species extinction worldwide after habitat destruction, and in islands, they are undisputedly first. The impacts of alien invasive species are immense, insidious, and usually irreversible. They are causing significant damage to the ecological, economic and health issues. As a matter of fact, they compete with native species, act as pests or pathogens for cultivated or domesticated species, or even disseminate allergic or infectious agents.

In its 2005 Meze declaration IUCN urge Governments and donor agencies to increase funding to facilitate the development of prevention, management and monitoring programmes, essential research, and economic analysis on invasive alien plants.

However, to set the record straight not all exotic species are harmful and some became harmful after passage of many years. Many of our plant species in India owe their origin abroad. According to a FAO report, out of the nearly 45000 (Fortyfive thousand) plant species in India, nearly 18000 (eighteen thousand) of those are exotics which corresponds to a massive 40% (Forty percentage). Only when these species start breeding rapidly colonising large areas by out-competing the local species for food/nutrition, producing allelopathic effects on other plants to inhibit their growth or simply constricting or killing them etc they get categorized as harmful or invasive species.

Mode of Introduction of Exotic or Invasive Species:

The exotic or invasive species can get introduced into a geographical region either intentionally or by accident. Accidental introduction of species happens either through travel, shipments of food grains, goods, logs and even by the ships.

Pet Trade spreads invasives:

It also happens due to legal and illegal trade of species that are often brought in as pets and later on escape into the wild on their own or released by their owners who find difficult to keep them. In USA, owners of Burmese pythons released them into the wild when they found these full grown pythons to large for their comfort. These pythons found Florida to be a suitable habitat and now Burmese pythons are in constant struggle with the alligators to don the mantle of the apex predators with size of the individual python or alligator deciding the winner. These pythons are creating havoc with the local wildlife who were not used to such a predator.

Similarly, there are many species that can breed with each other. So some of the exotic bird species which are brought in as pets get released from the house and can mate with the local ones contaminating the gene pool.

People often bring their pets or domestic animals with them to a new landscape and these being alien to that place create a huge impact. Similar is the case of introduction of deers for sport in islands which multiply fast without any natural predator. Though these pets and domestic animals are not readily viewed as invasives they do considerable harm. In a place like Andaman and Nicobar Islands, the introduction of goats, deers, elephants had a huge impact.

Scientific Experiments spreading invasives:

Exotic species can also get introduced into a country due to experiments scientific or otherwise. Teleonema scrupulosa is a case of deliberate introduction of a species in India. It was introduced to tackle the problem of lantana, however, they started attacking the teak plantations. They are still found in places in the wild.

In the past, African lions had been brought into India and released into the wild. However, all of them have been known to have been killed as they could not compete with the tigers.

The MoEF has approved a project to bring in African Cheetahs and introduce those in the wilds. (For further details: http://www.indiawilds.com/forums/showthread.php?t=1888 ). Since genetically they are different than the Asiatic cheetah that has gone extinct in India, if these African cheetahs ever manage to get released in the wild from their enclosures and start breeding successfully then they would become exotic invasives feeding on the few blackbucks left in the wild.

Major Invasive Species in India:

In India, lantana camara was introduced as a flowering plant in 1809 and it has gone wild to colonise most of our forests and degraded lands. Lantana which grows rapidly to form dense thickets above ground inhibits the growth of other plants. Infact, its cane-like low wood density helps in its fast growth. In India, its leaves were not eaten by herbivores. However, langurs have been observed eating the leaves and flowers.

Langur eating lantana

Birds serve as important agents in its pollination. Lantana is found more in degraded habitat and follows the destructive foot steps of humans as in road building, creating canals, fire lines in the jungles etc. This plant catches fire fast and burns even when it is green. So during forest fires, lantana acts in enhancing the fire. Manual control methods like repeated slash, uproot and burn technique repeated for a couple of years help. Also, immediately after the controlled burning plantation of native species is advised.

Parthenium hysterophorus an exotic noxious weed was accidentally introduced into India when its seeds came to India along with the grain imports in 1951. This quickly went on to establish itself in large parts of India, especially in the degraded lands, road sides, pastures etc. This weed like Lantana has allelopathic effects on other species and causes respiratory problems like asthma, skin infections etc. Apart from reducing the amount of grass and other edible plant species for herbivores, its impact on wildlife is yet to be studied.

Elephant & Calf struggle to get grass due to Parthenium invasion

Mikania micrantha, a climber species was introduced in India during the World War II to camouflage airfields. These climbers too have allelopathic effects on other plant species and it cuts the amount of light available to them. This species is mostly found in the moist deciduous forests and plantation in western ghats, north east etc. Plantations in the western ghats use herbicides on them. A biological control measure in form of Puccinia spegazzinii fungus is being tried out. Cuscuta a species of parasitic plants which have become a problem especially in South India are being tried to control the growth of Mikania micrantha species in Assam.

There are also many introduced species like acacia, eucalyptus, wattle etc which are harmful to the bio-diversity. Many plantation owners brought in these species for their fuel wood needs. The wattle due to its seeds retaining the capacity to germinate over longer periods of time is able to colonise grasslands, increases transpiration, dries up the soil and impacts the water percolating and appearing as streams. This impacts the balance of shola forests and grasslands in the Western Ghats. Eucalyptus, another species favoured by the plantation owners for fuel as well as the newsprint industry for making pulp, reduces the water table fast. Unfortunately, these are still being planted today.

Eucalyptus plantation in Sholas

Similarly, Gulmohur is a species introduced in India due to its colourful flowers. Though one of India’s foremost naturalist M. Krishnan was very vocal against planting this species, after his demise it seems people have forgotten that this is an introduced species.

In the acquatic ecosystems, water hyacinth or Eichornia crassipes which was introduced in India in 1914 has choked most of our wetlands. Coupled with eutrophication, these plants reduce the amount of oxygen available in water and lead to the death of the waterbody. It has become a huge problem in the backwaters of Kerala and several biological controls like curculionid weevil was introduced in India. Manual control ie weeding it out also helps. In places like USA, boats specially designed to cut the weeds are employed in the great lakes. These results in fragmentation and the fragments can grow elsewhere, however it helps in opening up large areas fast.

In India, exotic species like Gambusia affinis and Poecilia reticulata (commonly known as Guppy) were introduced to control the mosquito menace as these fishes were found to be effective in eating the mosquito larvae. There are indigenous species of fresh water fishes like Esomus danricus, Puntius ticto, Danio rerio, Rasbora daniconius that prey on the mosquito larvae. However, these fishes produce smaller brood than the Gambusia affinis and Poecilia reticulata and also they are susceptible to water quality, turbidity, temperature difference and transportation. Hence the Gambusia affinis was introduced in 1928 in India. Apart from eating mosquito larvae, these two exotic species didn’t appear to impact the other fishes. However, the actual impact of these two species on the micro-habitats of native acquafauna in India is yet to be studied in detail.

The British introduced Brown Trout (Salmo trutta fario) and Rainbow trout (Salmo gairdneri) in Kashmir and slowly in many other rivers in India. Though these are touted as anglers delight, a study by Blinn et al (1993) they are detrimental to the native species as they predate on the eggs and hatchlings of native fishes. According to Molur and Walker, the introduction of Silver carp (Hypophthalmichthys molitrix) has impacted the native fish populations in many places.

The spread of tilapia (Oreochromis mossambicus, Oreochromis niloticus) in our rivers and ponds is a cause of concern as it has out-competed our native fishes. Similar is the case with African catfish (Clarias gariepinus) which was illegally imported into India. The control method is to use fishing rods (difficult to eliminate all through this method), nets or simply draining out the waterbody completely. If the water body is small then the last mentioned method works as a good solution, however, if it is a large lake, then this physical control method simply doesn’t work. In a number of countries, anglers are encouraged to fish invasive species and use it for food, unlike other species of fish that has to be released back into the waters. Last year, there was a hue and cry when the forest department drained out the waterbody in Sultanpur National Park on the pretext of removing the African black fish, as there is an immediate impact on the nesting of birds that depend on fish.


A major problem that causes spread of invasive species in India and other parts of the world is ignorance. Some time back, the former President of India, Dr Abdul Kalam had proposed cultivation of sea weeds near Rameshwaram and other coastal areas. Little did he know that he was proposing introduction of an exotic species which in all probablility will move and colonise the entire Gulf of Mannar Marine National Park.

For example, Mimosa pudica also known as touch me not plant which had given us so much of pleasure during our child hood days due to its ability to close its leaves on external stimuli, was introduced form South America and has spread over vast areas in India. Since most of the people don’t know that certain plants are weeds, they don’t make any effort to remove them from their property.

Need of the Hour:

India needs to create a National Action Plan in fighting the spread of existing invasive species and preventing introduction of new exotic species in India. Till date we haven’t estimated an economic impact due to the presence of invasive species in India. Considering that Africa spends roughly about 100 million US Dollars annually to just fight the spread of water hyacinth, one can safely estimate that the overall impact of invasives in India is to the tune of billions of dollars. The newspapers may be grapple with the headline grabbing one lakh crore spectrum scam, however, the overall impact of invasives can be much larger. We urgently need a National Action Plan and bring together all the scientific expertise together along with evangelists who can spread the message to contain this menace of invasives.

Other Conservation articles:

A Wild Thorn: Silent Valey by Murali Sivaramakrishnan

Goa not keen for inclusion in Western Ghats World Heritage tag:

Impact of mobile towers on birds:

News from Top Slip:


Equipment Discussions:

Canon Announces Professional EOS 1D X camera with 3 brains: preview and discussions


Wildlife Photograpy:

Images shared by our members between 10th Sept 2011 – 9th October 2011 that depict interesting behavior, habitat or are just plain beautiful.

Salam Walaikum IndiaWilds: By Shalik Jogwe

Blackbuck habitat: by Mrudul Godbole

Shikra by Dr. Kalamoi Kakati

Spotted owlet by Bibhav Behera

Down Memorry Lane: Beauty of the Manas Tiger Reserve By Shaktipada Panigrahi

Jumping spiders by Abhishek Jamalabad

Millipede by Jitendra Katre


I look forward to your inputs and your support in preserving the last tracts of wilderness and wildlife left in this beautiful country. For other interesting articles and photographs please check: http://www.indiawilds.com/forums/

All the newsletters can be found online at: http://www.indiawilds.com/diary/category/newsletter/
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Sabyasachi Patra

Diary: http://www.indiawilds.com/diary/
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  1. Dear all,

    The Invasive Species Specialist Group (ISSG) aims to reduce threats to natural ecosystems and the native species they contain by increasing awareness of invasive alien species, and of ways to prevent, control or eradicate them.

    The ISSG promotes and facilitates the exchange of invasive species information and knowledge across the globe and ensures the linkage between knowledge, practice and policy so that decision making is informed.

    The ISSG manages and maintains the Global Invasive Species Database a significant repository of global invasive species information. (http://www.issg.org/database/welcome/). The ISSG also hosts an active listservice called Aliens-L with over 1080 members who exchange experiences, lessons learned and information. We also operate a referral service to assist with information needs and linkages to experts.

    We are keen to hear from you about the spread and impacts of invasive species in your area and encourage you to contribute and participate in Aliens-L.

    Please contact s.pagad@auckland.ac.nz for any assistance

  2. An article published in BBC News about impact of invasive Brown tree snakes in Guam.

    Battling the brown tree snake in Guam
    By Rebecca Morelle
    Science reporter, BBC News, Guam

    In the dense tropical forest, a slither of movement can just be made out in the glow of our head torches.

    A snake is entwined in the undergrowth. It is about 1m long, mostly dull brown but with a vivid yellow underbelly.

    We are face to face with Guam’s “nemesis”: the brown tree snake. And the forests here are dripping with them.

    The US territory, in the western Pacific, is only 50km (30 miles) long and 10km wide, but it is packed with two million snakes.

    This reptile arrived here only 60 years ago but has rapidly become one of the most successful invasive species ever.

    Unhealthy appetite

    Wildlife biologist James Stanford, from the US Geological Survey, says: “Our belief is that they came at the end of World War II.

    “We’ve looked at their genetics and they are all extremely closely related, and it appears they came from the Island of Manus in Papua New Guinea.”

    He explains that military equipment used by the US in Papua New Guinea while the war raged in the Pacific was eventually sent back to Guam to be processed. A snake probably crept on to a ship or a plane destined for the island.

    Cheryl Calaustro says the koko was easy prey for the snakes
    “And from that handful, or maybe even one already impregnated female, we now have a population that is unbelievable in scale,” he says.

    The snakes, which are mildly venomous, have caused many problems. They get everywhere, and people have even woken up with them in their beds.

    The island’s power system is regularly shorted out by snakes crawling on the lines. It is so frequent the locals now call power cuts “brown outs”.

    But the biggest impact has been on the wildlife – it has been decimated. The forests here are eerily quiet. Now the only place where the Guam’s native birds, such as the koko, can be seen on the island are in cages in a captive breeding centre.

    “The brown tree snake has had a devastating impact. Ten out of 12 native forest bird species disappeared in 30 years,” says Cheryl Calaustro from Guam’s Department of Agriculture.

    “The birds here evolved without predators. They were quite naive. And when the snake arrived on Guam it ate eggs, juveniles, adults. Whole generations disappeared.”

    Toxic mouse bombs

    But the snakes did not stop there.

    Dr Stanford explains: “We thought it would be limited: ‘OK, if it wipes out the birds, it will decline.’ It wasn’t the case. It just switched what it was feeding on – rodents, lizards, small mammals – across the board.”

    Now the locals are fighting back. And they are unleashing some unusual weapons in their war against the snake.

    One effort has involved air-dropping mice that have been laced with poison and fitted with parachutes out of helicopters. It provides a deadly dinner for any unsuspecting snakes below.

    “Right now we are using acetaminophen (paracetamol). It commonly used as a pain reliever and fever reducer in humans, but it is 100% lethal to all brown tree snakes,” explains Dan Vice of the US Department of Agriculture.

    “If they eat that dead mouse containing acetaminophen, they will die.”

    But this is a battle on two fronts. Not only is the US government trying to clear the snakes, it is also trying to prevent the problem being passed to anyone else.

    And to do this, it has enlisted the help of some small dogs.

    Snakes on a plane

    In a busy cargo depot close to the airport, Elmo the Jack Russell, kitted out in a smart, green uniform, is sniffing box upon box of goods waiting for export.

    He is on the hunt for any unwanted stowaways.

    As he catches wind of an unusual scent, he begins to scrabble, alerting the government inspector to the presence of a snake – and is rewarded with a treat.

    A small army of dogs check every single item of cargo before it leaves Guam.

    “It is a monumental project. We’re working 24 hours a day, seven days a week,” says Mr Vice.

    “Cargo doesn’t stop, the airport doesn’t shut down, so we have to be there to make sure the cargo going on the airplane has indeed been snake inspected.”

    Letting the snakes on a plane could have devastating consequences.

    Mr Vice says: “Economics researchers have tried to apply the impact of snakes to Hawaii. They found it could cost $400m or more if the snake became established.

    “The impacts are running across all kinds of parts of the economy. It includes healthcare for humans because the snakes bite people, damage to the power system, lost revenue associated with declines in tourism and ecotourism.”

    However, with so many snakes on the island, controlling the problem is an uphill battle.

    And today, Guam serves as an example to the world of what happens when an invasive species takes hold.

    The worry is that it may be too late to clear the infestation, but Mr Vice says this should not stop the islanders from trying.

    “Our long-term goal is to eradicate the snake,” he says.

    “The problems here are so profound we don’t want to let them go anywhere else, and the only way to achieve that is to get rid of them completely.”

    The source article and more on this can be found here: http://www.bbc.co.uk/news/science-environment-17992053

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