Invasive Weed Threatens to Overrun Nature Reserve

plant invading nepal photo Photo via the BBC

Authorities at Nepal's Chitwan National Park are sweating over an unlikely menace which threatens to overrun the 230,000 acre nature reserve, home to some of the world's most endangered species. The culprit is a fast growing plant, called Mikenia micrantha, native to Brazil, which has already succeeded in covering 20 percent of the park--and it shows no signs of slowing. Park officials have taken to uprooting the weed after seeing realizing the potentially dire threat it could have on native species, but that may not be enough. "If uncontrolled, it will spread over half of the park's entire area."Invasive Weed Disrupting the Food-Cycle
According to a report from the BBC, Mikenia micrantha has spread throughout regions of the park that are home to some of the most endangered species--like the Indian Rhino, Bengal Tiger. The weed has overrun native plant-life and threatens to impact the delicate balance of ecosystem, since less grass could mean less deer--and less food for the rare tiger.

Rhinos too, of which only 400 remain inside the park, may find life difficult with the unwelcome plant. The park's chief warden, Narendra Man Babu Pradhan, explains:

We call this vegetation imposition. For example, there is this tree that bears fruits called 'rhino's apple' that is killed once it is covered by the [weed]. This means a food source for the rhinos becomes scarce.

Rhino Droppings Speeding the Invasion
While the invasive plant may be driving some animals out of the park to maintain their diet, researchers have observed some rhinos eating the stuff because the weed has strangled out so much of the native grasses normally on their menu. This exotic meal for the rhino only serves to compound the problem, however, since the plant's seeds are further distributed in the animal's droppings.

The battle to stave off Mikenia micrantha has been hard fought. Because the use chemicals to exterminate the invasive plant might have an adverse effect on native vegetation, park authorities have been forced to uproot it by hand. Still, all that work doesn't seem to have slowed the plant's spread. "The weed covered areas near wetlands, grassland and open places in the forest," says one biologist, but human and animal traffic continue to introduce it to other areas.

How Did the Plant Get From Brazil to Nepal?
It is believed that Mikenia micrantha was first brought to the region during World War II to be used as camouflage for army camps, but the plant soon found the moist soil ideal to facilitate its rapid growth. The BBC reports that some nature reserves in India may be facing similar problems from the weed.

For the sake of the native wildlife that call Nepal's Chitwan National Park 'home', it should be the hope of conservationists everywhere that a solution be found to this potentially devastating problem. And, drawing a lesson from all this, we are once again reminded of how delicate a balance is required to maintain the world's ecosystems--and of how easily it can be disrupted by the most unlikely sources.

More on Invasive Species
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Invasive Species: When Small Creatures Do Big Damage
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Tags: Biology | Conservation | Endangered Species | Nepal


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