Source:
http://x.dawn.com/2011/02/06/islamabad- ... ded/print/
Islamabad: The aliens have landed
by Zahrah Nasir
February 6, 2011
A biodiversity catastrophe of monumental size has occurred in, and around, Islamabad over recent decades, yet few people are actually taking notice of the long term environmental impact of man-made intrusions into the natural ecological balance of the area.
The introduction of potentially harmful plant species from overseas, except for that prime offender the paper mulberry, is largely ignored with the result that indigenous flora, along with birds, bees, butterflies and other beneficial insects, are placed under increasing, sometimes intolerable, levels of stress. In addition to which rapid expansion of constructed areas and other necessary infrastructural procedures are moving endemic species towards an irreversible tipping point beyond which they will become, locally at least, extinct.
Paper mulberry (Broussonetia papyrifera) was introduced to Islamabad from South East Asia over 30 years ago and rapidly became a major problem. The idea behind bringing in this alien species was to green up Islamabad as fast as possible. In the process of achieving this goal, however, it quickly became apparent that the pollen of this tree was to blame for debilitating pollen allergies suffered by the city’s inhabitants and, as the trees naturalised, by those living in rural areas adjacent to the city, too. By the time the CDA woke up to the misery it had inflicted on its citizens, paper mulberry was, loving the climate as it does, too well established to eradicate.
The numerous, costly campaigns launched to destroy these trees is actually causing them to multiply as, when the trunk of a paper mulberry is cut down, it fights back by sending up fast growing shoots from its extensive underground root system by the thousands. The problem doesn’t stop there either: cutting down each of these new shoots actively encourages another multitude to come up!
Exactly who was behind the introduction of another invasive alien species, Lantana camara, a frost resistant tropical American shrub, is unclear and concerned authorities have failed to take remedial action, perhaps considering that it is too late for this. To add to the problem, nurseries still openly sell this species and buyers are many. Lantana shrubs have completely taken over thousands of acres of land lying between Islamabad and Barakhu and have colonised many other areas too, where they have wiped out many species of indigenous plants, thus adversely affecting localised ecosystems to an alarming extent.
The seeds of this shrub are spread mostly by birds who, unfortunately, find their berries irresistible. There has not yet, to the best of the writer’s knowledge, been any attempt made to prevent further spread of a species which has completely destroyed grazing and previously cultivable land in many places. To the contrary, noted botanists such as Rubina Rafiq and Yasin Nasir, have stretched credibility by listing it in their 1995 book, Wild Flowers of Pakistan (OUP, Karachi) which sets a dangerous precedent indeed.
Unregulated nursery owners are openly importing alien plant species from countries including Indonesia and Malaysia without, it appears, paying due consideration to potential problems they might, unwittingly, bring with them. Gardeners, always keen to try something new, are also happily cultivating these exotics which could, in the future, badly impact the environment and all who live in it, be they human, animal, avian, members of the aquatic or insect world and, of course, irreplaceable indigenous flora.
All of those with an interest in the plant world, from government departments to private companies and home gardeners, badly need to develop an understanding of how imported species can contribute to environmental degradation over the coming years. They would be better advised to grow indigenous species instead as these would be highly beneficial to all aspects of the natural world on which humans depend for their survival.
If, for example, the CDA had elected to plant indigenous trees in Islamabad instead of Paper Mulberry, allergy related problems would not be harming the health of the population who are currently forced to spend millions of rupees annually on seeking medical solutions. Likewise, planting indigenous trees, those appropriate to local climatic and soil conditions, would benefit everything from insects upwards as their systems have evolved in symbiosis with these rather than with ‘foreign’ things from which they often derive no sustainable benefit.
Planting of indigenous species has further benefits too: Monetary savings accrued through the purchase of less costly indigenous species could be utilised for associated environmental protection and improvement programmes. Water savings could also be massive as indigenous species rarely require the copious amounts of this increasingly precious liquid that alien species do and, as a direct consequence of this, labour savings, in the form of time, could release employees for work on more easily sustainable projects.
If Islamabad is to remain in any way green, it is imperative that the high cost import and planting of potentially invasive plant species is brought under control as soon as possible as, whilst it is true to say that climatically unsuitable ones do die off, those that find Pakistan to their liking, damage the country long term.
