Undesirable aliens

Undesireable Aliens

What is common to a water weed and a thorny shrub found in India, a rodent mammal found in Australia and a New World perching bird, asks Maitreya Sukumar, one of our youngest Guest Editors.

Aliens or Invasive species

Let me give you a hint: the weed is the Water Hyacinth (Echhornia crassipes), the shrub is the Prosopis (Prosopis julifora), the mammal is the rabbit, and the bird is the Common Starling (Sturnus vulgaris). All of these are aliens or introduced species that have taken over the local environment. In short, they are invasive species.

Species like these are really bad for the environment because they reduce biodiversity, threaten the survival of local species and disrupt the ecology, according to Daniel Allen in his book, The Nature Magpie. “Their presence is also damaging to the global economy, costing an estimated $1.4 trillion (roughly Rs 84trillion) a year,” writes Allen.

Invasive species are usually brought in accidentally, although sometimes they are also introduced deliberately. Often, they are brought in by people who do not know what they are doing —like the Burmese Pythons, that are a big problem in the Florida Everglades after a few pet pythons escaped.

In India, the two most damaging invasive species are the Water Hyacinth and the Prosopis. The Water Hyacinth was introduced as an ornamental plant because it has pretty purple flowers, but it rapidly took over wetland waterbodies, affecting local fish and bird species. According to some scientists, each Water Hyacinth plant can produce up to 3000 seeds a year and the seeds can live for up to 20 years. Similarly, the Prosopis was introduced as part of India’s afforestation project. The plant is hardy and grows fast. Some scientists say that it nourishes the soil and that it can be removed after a few years when the natural venation of the area is planted in its place. Unfortunately, this has not happened widely in India, though pockets of success are present, such as in Delhi’s Aravalli Biodiversity Park. As for the killer of India’s wetlands, the Water Hyacinth, there is no cure but cutting and burning.


African elephants in danger

African bush elephants (Loxodonta africana) may become extinct in a few decades, according to a new paper in Proceedings of the National Academy of Sciences. The main cause for this is poaching for ivory. Around 100,000 elephants have been killed for their tusks in the past three years. Also affected are Central Africa’s Forest elephants (Loxodonta cyclotis) whose numbers have drastically declined by 60 per cent since 2002. The paper says the only solution is to shut down ivory markets. China is the biggest market for ivory.

The largest bird that ever flew

Recently, scientists in South Carolina in the United States discovered the fossil of what they think could have been the largest flying bird. It is believed to have lived around 25 million years ago. The scientists have named it Pelagornis sandersi and believe it was a giant seabird with a wingspan of 24 feet. The largest flying bird today is the Wandering Albatross (Diomedia exulans) which has half the wingspan. The Pelagornis and the albatross may well be related.


Article originally published in Oct 2014 Issue of Saevus Magazine

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About the Author /

Maitreya, is a passionate birder and has seen over 500 Indian and almost 1000 global species of birds. He studies at the Shri Ram School, Moulsari Avenue, Gurgaon.

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