Scientists uncover UAE’s ‘alien’ plant invasion

    28 Jan 2023

    The UAE prides itself on being a society that welcomes newcomers — a kindness extended even to plants, a study shows.

    Scientists have found a growing number of “alien” plants are arriving in the Emirates, but not all are proving to be ideal guests.

    Their research has identified for the first time five species from other parts of the world that have put down roots in Fujairah.

    These follow others, previously identified, that have arrived and settled in the country. Among them is a tree notorious for outcompeting native flora and using large amounts of water.

    “As we progressed in our research, we began to increasingly find plants that had escaped from the culture, but still remained close to humans: on [irrigated areas], at the outlets of pipes from air conditioners,” said Mikhail Korshunov, one of the two authors of the study.

    “Many species of ornamental plants, which were brought at first to plant nurseries, started to escape. So we came up with the idea that we need to go to the source of alien flora — plant nurseries.

    “And there, from the very first attempt, we were encouraged by a huge number of plants that began to naturalise. Almost every next trip to a new plant nursery for research brought new finds.”

    New to the UAE

    One species, painted spurge, which is fond of sandy soils, was found growing freely at a plant nursery in Dibba, while another, chay root, was discovered on the seafront at Fujairah. Neither had previously been recorded on the Arabian peninsula.

    Seaside rivuletweed was found at a nursery in the Al Badiyah area, while East Indian mallow, which is common in wastelands in India, was identified at a nursery in Dibba, and the researchers discovered a climbing plant called lesser balloon vine or love in a puff at the Friday market in the village of Masafi. These three were all new to the UAE.

    While there is no evidence of any of the five species becoming invasive, meaning that they are spreading quickly and causing harm by outcompeting local flora, this has happened with certain plants and animals transported to new areas.

    Sometimes this is because the animals that consume them for food back home are absent in the new place, allowing the introduced species to reproduce and spread freely.

    In certain instances plants have taken more than a century to become invasive, so plants having little impact now may become a nuisance later.

    The research was done by Mr Korshunov, who is completing a PhD on his work in the Emirates at the Russian State Agrarian University in Moscow, and Dr Vyacheslav Byalt, of the Komarov Botanical Institute of the Russian Academy of Sciences in St Petersburg.

    The new paper, published in a scientific journal called Turczaninowia, is one of several from a project they undertook between 2017 and 2022 under the patronage of Sheikh Mohammed bin Hamad Al Sharqi, Crown Prince of Fujairah, and the authorities in the emirate.

    Green shoots of discovery

    The Fujairah government’s acting environmental adviser, Dr Vladimir Korshunov, who is Mr Korshunov’s father, supported the research.

    While the research was taking place, in 2018, the Fujairah Environment Authority was created, and the scientists worked closely with the organisation.

    Also launched in association with the study was Fujairah Scientific Herbarium, which now has 11,000 plant specimens, making it the second-largest collection of its kind in the UAE.

    Mr Korshunov said that researchers often ignored cultivated plants, but they have sometimes escaped and become established in their new location.

    “All cultivated plants propagated vegetatively or by seed have the potential to become invasive in the area where they are introduced,” he said.

    “Most findings are in plant nurseries and [cultivated] landscape greenery. They came in the last few decades from Pakistan, India and south-west Asia.”

    Mr Korshunov said that in addition to the cultivation of plants in nurseries, the growing of crops has resulted in species being introduced to the UAE.

    Among the world’s most notorious invasive plants is Japanese knotweed, which has been branded “a global menace” because it spreads rapidly, is difficult to eliminate, and has been blamed for structural damage to buildings and walls.

    Because of its harsh climate of high temperatures and low rainfall, the UAE is better protected than many other locations from invasive species, Mr Korshunov said, as many non-native plants find it hard to thrive.

    Horticulture’s hostile takeover

    One alien plant that has spread widely in the UAE, however, is a tree called Prosopis juliflora, which is what scientists term a biocoenosis transformer, meaning that it not only outcompetes local plants, but causes wider changes to the local ecosystem, including to soil quality and animals. This tree also takes large amounts of water from underground.

    “It can stop sand from moving in dunes, but [there is a] price for it — less local species remain,” Mr Korshunov said.

    In another study, released by a different group of scientists in early 2022, satellite image analysis showed that the species covered an area of 0.2 square kilometres in the northern UAE in 1990, but 16 square kilometres in 2019.

    “The areas near Sharjah Airport, Umm Fannan, and Al Talla, located at a lower elevation of the sand dune area, are heavily invaded,” the researchers wrote in the journal Plants.

    Mr Korshunov and Dr Byalt too have mapped this invasive species with the aim of assisting efforts to control it.

    “We have developed and tested in Fujairah a five-level assessment of the success of local micropopulations of Prosopis juliflora, with the results recorded on the map. It will help develop measures to control and combat this invasive species,” Mr Korshunov said.

    Dan Eatherley, an environmental consultant in the UK and author of Invasive Aliens, a book about invasive species, said that while plants and animals have been deliberately transported across the world for hundreds of years, now this happens more quickly and easily.

    “They might be aesthetically pleasing or provide food or other products,” he said. “This intentional trade has increased. There’s more opportunity for plants to spread by this method.”

    The technology to preserve plants in transit has improved, he added, which also increases the opportunities for introductions, as has more frequent human travel across the planet.

    People might carry plants in their luggage or, without realising, transport seeds or spores stuck to their clothes or in soil that imported plants are growing in.

    Potentially invasive animals, such as insects, may “hitch a ride” on plants that are being transported, Mr Eatherley said.


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