People, Environment

Alarming Increase in Tehran’s Invasive Plant Species

Alarming Increase in Tehran’s Invasive Plant SpeciesAlarming Increase in Tehran’s Invasive Plant Species

A number of invasive plant species have been growing in Tehran’s urban ecosystem, threatening the native flora and raising the risk of diseases communicated through animal products.

Speaking to ISNA, Ahmadreza Mehrabian, the head of Environment Museum at Shahid Beheshti University, warned against the overwhelming growth of these unwanted plants in the capital.

In urban ecosystems, these troublesome species appear as bushes and weeds. Euphorbia (or spurge) is one of the species that has spread in the outskirts of Tehran and is rapidly covering swaths of pastures.

“This plant is toxic and products derived from livestock feeding on it may be toxic to humans,” said Mehrabian.  

Ailanthus is another invasive plant in Tehran which, due to its fast germination, grows quickly and eliminates the tree species in the area.

Abandoned lands in the suburbs are suitable spots for the growth of such plants.

“As soil degrades and loses its minerals, resilient invasive species such as acanthus, wallflower and cornflower proliferate in the area,” he added.

In a biodiverse environment, “there is no such as an invasive species,” but human activities and interference “disturb the natural balance, giving one species a critical advantage over others, helping it spread quickly and take over”.

Another factor that contributes to the emergence of invasive plants is transgenesis, the process of introducing an exogenous gene—called a transgene—into a living organism so that the organism will exhibit a new trait and pass it along to its offspring.

“This can lead to the appearance of superweeds that are resistant to pesticides,” said Mehrabian.

Taking stock of the negative impacts of invasive species, he said that once they attack an ecosystem, they remove the natural species that have developed and evolved in the area over millions of years and the habitat eventually loses its natural flora and even fauna.

“Across farmlands, they spoil the quality of soil and disrupt agricultural practices, leading to economic and social issues,” he said.

These intrusive plants can also contribute to dust storms by eradicating natural vegetation across wetlands, as a result of which aquifer levels drop and soil particles lose their adhesion, leading to their easy dispersal into the air.

“This befell the Hamoun Wetlands in Sistan-Baluchestan Province,” he said.