Local plants losing ground to invasive alien plants in Margalla Hills

Islamabad : The invasive alien plant species are now competing aggressively for access to sunlight and water thus causing negative impacts on local plants that are fast losing ground in Margalla Hills National Park (MHNP).

According to a data compiled by Islamabad Wildlife Management Board (IWMB), there are mainly five invasive alien plants species in the Margalla Hills including lantana, castor oil plants, common cocklebur, paper mulberry and carrot grass.

The details revealed that the lantana that is locally called ‘Panch Phulli’ is about three meters tall and an evergreen shrub with pink and yellow flowers. It is competing heavily with local plants on south-facing slopes of the Margalla Hills where it has overtaken native vegetation along stream beds, roads, croplands and even forest areas and pastures. Although its seeds are edible the leaves are toxic to livestock.

The local name of castor oil plant is ‘Arind’ or ‘Harnoli’ and it is usually found in disturbed areas of MHNP such as disused agricultural lands and dry streambeds.

It is quite common in villages of Saidpur, Nurpur and around Rawal Lake. It occurs as shrub and tree, flowering throughout the year and spreading through its seeds, which are poisonous to plant-eating mammals but has a limited industrial and medicinal use. Its pollen is known to cause allergies.

The common cocklebur (local name Kandiari) reaches about 1.5 meters and regenerates annually, flowering from July to October. The fruit are oval-shaped burs covered with hooked spikes that enable them to stick to the coats of animals or clothes of human beings.

It is now floating downstream to colonize new areas in hills and spreading rapidly on a wide range of disturbed soils along roadsides and eroded streambeds.

The local name of carrot grass is ‘gandi booti’ and it is one of the highly invasive ruderal plants in the Margalla Hills. It regenerates each year and produces clusters of small white, disc-like flowers. It spreads through seeds and colonizes disturbed areas in overgrazed rangeland, alongside roads, trails and tracks. All parts of this plant are poisonous and may cause skin allergies and respiratory problems in humans and their livestock.

The infamous paper mulberry was imported from China some forty years ago. It grows fast and once taken root can grow over a meter in a good monsoon. It has become a threat to the natural vegetation and a source of allergies caused by its pollen.