The research, Ediphytes of Karachi, conducted at the botany department of Federal Urdu University of Arts, Science and Technology (Fuuast), will be published in the recently launched Fuuast Journal of Biology.
Syed Sadruddin Hussain and Mohammad Faheem Siddiqui carried out the two-year research under the supervision of Prof Dr Moinuddin Ahmed, who heads the university’s lab for plant ecology and dendrochronology.
The study’s objective was to identify and locate the places where the plant species were growing in the façade and draw the public’s attention towards the damage the plants are causing to civic infrastructure.
During the study, ediphytic trees including woody climbers and herbs of Karachi were examined. The plants belonged to 17 families and 25 species, with most of them members of the Moraceae family of genus Ficus (peepal). The extent of damage to the building was also recorded.
Ediphytes (a composition of two Latin words meaning building and plants) are vascular plants growing from moist wall crevices, fissures and cracks of buildings and other civic infrastructures such as ramps of bridges and flyovers. They are an indicator of neglected and dilapidated buildings, according to the study.
“These plants have adapted themselves to live in stress conditions of crevices. Their seeds are light, small and mostly inconspicuous and can reach the building material through the rain or wind. They can also reach the crevices through biotic agents such as insects, birds, bats, rodents or human beings. These can cause cracks and damage to the facade of the
building,” the study says.
During the study, ediphytes were mostly seen around leaking sewage pipes or where the place is moist due to dripping water pipes. In some places, they have even invaded newly constructed structures like the Lyari Expressway and Liaquatabad flyover.
“In the case of newly built structures, one could say that their seeds must have already been present in the building material when the construction began and those that were located on the outer side of the structure managed to sprout. The roots of some ediphytes release acid that softens the building material and helps the plant grow,” Dr Moinuddin Ahmed explains.
The urban setting of Karachi, according to the study, provides numerous opportunities for such plants to thrive. Building surfaces have niches for specialised blue-green algae. Many angiospemic plants such as herbs, shrubs climbers and trees, have also found these wall crevices a suitable habitat. They are also called crack flora or wall flora.
Regarding the damage the plants cause to the structure, the study says that the most destructive part is their roots which find their way into the cracks and over time exert tremendous mechanical and hydraulic pressure that separate bricks and plaster and displaces the concrete to create even larger cracks in the building.
The study says: “With the passage of time abandoned and dilapidated buildings can be toppled and their man-made materials disintegrated into rubble. In this way, the plants can reclaim their lost territory invaded by man long ago.”
The study suggests that the Karachi Building Control Authority, the city government as well as the people living in such buildings need to take the menace of building plants seriously and remove them.
“At many spots, we found that the blocks in which the plants were growing had either shifted or had partially come out of the whole structure,” Dr Ahmed said, adding that regular inspection and repair of civic infrastructures could help avert disaster.