The ecologically-rich Anzali Wetland in Gilan Province is now threatened by water hyacinth.
The wetland had earlier been besieged by water ferns native to the tropical regions of the Americas, East Asia and Australia and extremely invasive outside its natural habitat.
Water hyacinth, native to the Amazon basin, has begun growing in the wetland’s southernmost region, the Persian daily Hamshahri reported.
Unless swift action is taken, water hyacinth will swiftly and aggressively cover the entire wetland, which will dramatically impact water flow, block sunlight from reaching aquatic plants in the depths of the water and starve the wetland of oxygen, killing whatever marine life it hosts. The physical biomass can prevent boat movement or angling.
The wetland already suffers from high levels of sedimentation and it has become the dumping ground for urban and industrial waste, which together have reduced the depth of the wetland by 9 meters.
Reckless Import of Plants
While it is not exactly known how water hyacinth found its way to Iran, some experts speculate that the plant was imported.
Water hyacinths are in high demand as household plants due to their muted purple color.
“People who import flowers and plants must be careful when bringing invasive species over to Iran,” said Alinejad, an environmental expert.
He said nearly 4 kilometers of Morghak River, which feeds into Anzali Wetland, is covered with water hyacinth.
Like most other environmental issues in Gilan involving water, this problem may very well extend to the Caspian Sea, and there is no telling how severe the impact will be. Given the size of the sea, controlling the spread of invasive species in the Caspian Sea will be a herculean task.
Controlling the growth and spread of water hyacinth, called by some plant scientists as the worst aquatic plant species, requires millions of dollars every year, highlighting the importance of controlling the import of highly invasive species.
Water hyacinth is a floating plant with thick, glossy, round leaves, inflated leaf stems and very showy lavender flowers.
Water fern is a small free floating fern that grows and proliferates in canals, ponds and sheltered aquatic habitats and it is tolerant of brackish water. Like water hyacinth it can carpet the water surface over considerable areas.
