Infiltration of native plant species

Amid the countrywide campaigns for tree plantation and social forestry, few think of the reverse aspects of these advocacy-based drives. These trees generally grow in the form of invasive foreign plants, a branch of the invasive alien species (IAS). The broader group includes mostly plants, animals and pathogens. These organisms are foreign to an ecosystem and are potently harmful to the environment of a country. They also have the capability to leave adverse impacts on human health. Coming to the invasive alien plants, many feel tempted to recall the heated debates sparked by eucalyptus tree plantation in Bangladesh and elsewhere. Those occurred decades ago. Eucalyptus is now viewed as one of the highly invasive trees in the world. Thanks to a well-orchestrated campaign by environmentalists, the trend of growing eucalyptus eventually fizzled out.

Another plant species called ipil-ipil made news in Bangladesh in the 1980s. Experts didn't waste time to declare that the tree renders its surrounding land unusable. They were of the opinion that ipil-ipil reduces species diversity, wiping out native species.  

As has been noted by a section of botanists, harmful exotic plant species have long been found lurking amid the centuries-old indigenous trees of the country. Few tree-lovers and cultivators have the special knowledge and capability to single out these alien trees. A study conducted by the environment and foreign ministry has recently located a total of 44 exotic plant species in the country's protected areas. It has also identified 17 plant species under the category of 'foreign invasive plants' in the nationally protected forests. Amid the ongoing enthusiasm over social forestry and similar other tree plantation programmes, the infiltration made by invasive plants emerges as a potential threat. The presence and fast expansion of these alien trees has been a well-known fact; but the distressing truth about them is the common people's inability to identify them. Meanwhile, the alien trees continued to wreak havoc on the trees grown in special zones like protected areas. Thanks to the vastness of the reserve forests and vigilance carried out by numerous specialists and volunteers, the country's forests couldn't be encroached on by the invasive foreign plants.

Many of the IAS plants enter a country as part of an age-old natural process. The theory is contrary to the concept of deliberate human efforts to inflict damage on the flora and fauna of a targeted country. There has yet to be any concrete proof of applying biological weapons by any country against a hostile one. This strategy used as an act of sabotage, was first adopted by Germany during WW-I. However, biological wars are a staple for today's sci-fi movies. Yet few can assert that Bangladesh has the ability to rest assured over the fact that its reserve forests and the naturally grown woodlands are free from the machinations hatched by illegal loggers. They can smuggle into the country the saplings or seeds of IAS plants to grow them into logs. They cannot be expected to feel worried about the great harm to be done to the country's forest resources by the alien trees.  

In this regard, a biodiversity conservation researcher observes that alien species have the ability to compete with the indigenous species in the protected forests, change the ecosystem and disrupt the food chain. He recommends taking advanced measures, including early detection and screening of foreign plants. The expert came down hard on a section of quarters behind some government afforestation ventures. He holds them responsible for the increasing number of foreign invasive plant species. The expert singles out the Madhupur Saal Forest in Tangail as an example where some foreign invasive plants have been introduced. The forest has been largely damaged by the entry of those species. The mangrove forest of the Sundarbans has long emerged as one highly vulnerable to the insidious assaults of invasive foreign plant species. 

The workings of invasive alien plants are quite unique. These species are those that are introduced into new areas. Once there, those are able to adapt, become established, and reproduce and spread, colonising new areas, explains Encyclopedia Britannica. Elaborating on the process, it says invasive species, like any non-native plants, significantly modifies or disrupts the ecosystems they colonise. Many query about the way in which these species change places. The answer is they may arrive in a new area through natural migration. But they are often introduced by the activities of other species. Human activities, such as those involved in global commerce, are considered to be the most common ways in which invasive plants, microbes and other organisms are transported to new habitats.

Some of these species may become invasive when they possess a built-in competitive advantage over native species in the invaded areas. The ecological disruption that tends to follow such invasions often reduces the ecosystem's biodiversity and causes economic harm to people who depend on the ecosystem's biological resources. Contrary to some common myths, the invasions of alien species have no deliberate human involvement. But many deny it. An ecology and biodiversity conservation researcher demands that the relevant authorities make probes into what is the origin of IAS plants identified in the protected areas and who are behind bringing those into a country. Experts are unanimous on the fact that local plants cannot grow properly beneath the alien ones as they prevent the native plants from absorbing nutrients from soil. Given a plethora of grim realities vis-à-vis the increasing encroachment on native flora reserves by alien plant species, there is strong logic in favour of stringent measures for saving the country's plant resources.

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