Invasive plants from Ernakulam are fast spreading across the State, thereby affecting the plant diversity of the region.
Invasive plants are non-native species that upset the biodiversity and economy of a region through their rapid spread across landscapes. These species are introduced either accidentally or purposefully to new areas.
Researchers who looked into the spread of invasive plants across the State found that Ernakulam district served as the hub of these unwelcome guests. The district also has the highest concentration of invasive plants.
An assessment conducted by the researchers of Kerala Forest Research Institute (KFRI), Peechi, revealed that 41 species of invasive plants were present in Ernakulam. Of these, 16 belonged to the high risk category, which are capable of wiping out endemic species and causing economic and ecological losses.
The Seaport-Airport Road linking the Cochin Port Trust to other parts of the State could be termed the invasive highway of Kerala as a large number of the exotic plants were spotted there during the study, said T.V. Sajeev, an invasive species expert who was part of the research team.
Import of timber and foodgrains through the port is believed to be the main source through which exotic plants found their way into the State.
There is a high possibility of seeds being distributed through the import of timber. Chances of live plants being introduced through timber are relatively less as consignments from faraway destinations take considerable time to reach here.
However, seeds could survive long journeys and germinate in favourable conditions, researchers said.
The non-native plants found in the district included two tree varieties — Lead tree and Jamaican Cherry. There were several varieties of herbs, shrubs and climbers too. The plants also showed maximum growth in the region as the climatic conditions were akin to that of their native regions, said T.A. Suresh, a research associate.
Coral Vine, Giant Reed, Siam Weed, Grape-leaf Wood Rose, Mile-a-minute Weed, Giant sensitive plant, Prickly sesban and Singapore daisy are some of the exotic varieties found in the district. Most of these plants were natives of Latin American countries, the study pointed out.
Vehicular movements from the port increase the chance of spread of invasive species. The movement of soil from other areas to the port region for reclamation also contributed to the growth and spread of such plants, researchers said.
They also pointed out that a few species found in the State, such as Lantana and Singapore daisy, were earlier purposefully introduced for gardening and medicinal purposes.
With international trade and transport on the rise, there is the risk of introduction of more such species. Strengthening phytosanitary measures was the only way to check the spread of these species, said Dr. Sajeev.