Development and urbanisation often destroys wildlife habitats but researchers have found that, for the UAE’s amphibians at least, it may have an upside.
Researchers say urban lakes and ponds have become habitats for Dhofar toads, one of only two amphibious species native to the country, demonstrating how certain species can thrive in areas transformed by people.
The Dhofar and the Arabian toad were thought to be found only in the Hajar Mountains and the Al Ain area. But the researchers found a breeding population of Dhofar toads near Abu Dhabi city in a small public park, the location of which has not been disclosed to ensure the animals are not disturbed.
The toads may have been taken there deliberately – as the nearest population is 112km away and in between there is what the study calls “inhospitable desert” – or they may have been introduced accidentally. Another population of Dhofar toads is said to be living in an area of Abu Dhabi which features a golf course and the gardens of a beach hotel.
Increased irrigation in residential areas and farms could “provide suitable conditions for species such as the Dhofar toad”, says the study’s lead author, Pritpal Singh Soorae, an animal assessment and monitoring expert in the Terrestrial and Marine Biodiversity Sector at the Environment Agency Abu Dhabi. This, he said, enabled these animals to “expand their range within their native habitat”.
“The populations around Abu Dhabi city of Dhofar toads could be accidental introductions but, due to the abundance of green spaces such as parks and golf courses in an urban landscape, these species have managed to be abundant in many areas,” he told The National. “This also shows that cities can play a role in species management and conservation, as green spaces can be utilised by myriad species.”
Going native
Titled Conservation Status of Amphibians in the United Arab Emirates, the study has been published in Status of Decline and Conservation of Amphibians of the Middle East. The other authors are Ahmed Ali, of the agency; Prof Salvador Carranza, director of the Institute of Evolutionary Biology at Pompeu Fabra University in Barcelona; and Marsenia Haris, of Emirates Park Zoo and Resort, Abu Dhabi.
As well as highlighting how development has opened up new habitats for the UAE’s amphibians, the research details threats that they face. These include the extraction of water from wadi systems that the animals use, and development, as roads can cut across the creatures’ habitat. Off-road driving through wadi beds and pools of water is another hazard.
Threats could intensify if the environment becomes more arid as a result of climate change, with the Arabian toad being especially vulnerable because it requires permanent water sources. This species is limited mainly to wadi and dam systems, where it breeds and lives.
“If climate change brings increasing aridity, [Arabian toads] will face a challenge to survival,” Mr Soorae said. "Therefore, the protection of their main wadi habitats is important."
Prof Carranza echoed this, saying that amphibians could suffer “significant declines in their population” if water sources such as natural wadis, springs and seasonal pools are lost because of development, water extraction or climate change.
“Maintaining natural hydrological cycles and protecting key freshwater habitats is essential to ensuring their long-term survival, particularly in a country where permanent freshwater sources are scarce,” he said.
Neither the Dhofar toad nor the Arabian toad are threatened, classified as of “least concern” by the International Union for Conservation of Nature, and population of each species is stable.
“In Abu Dhabi [emirate] we have Dhofar toads mainly in Al Ain, where they are found in wadis,” Mr Soorae said. “Once a huge breeding event was observed in Al Ain city with over 2,000 metamorphosing toadlets recorded. This shows that preserving the wadi habitats in cities such as Al Ain provides critical habitats for these species to breed and survive.”
Dhofar toads also breed in temporary pools created by rainfall, so their eggs and tadpoles can be found in such pools far from permanent water sources.
As well as having “every right to exist like other species”, Mr Soorae said the UAE’s two toad species “play an important role in the complex food web of aquatic ecosystems”. This can include, he said, nutrient cycling, when they excrete waste, and eating harmful insects.
Widespread impact of urbanisation
Mr Soorae said the agency recommended keeping native species within their natural habitats, so deliberate introduction of the animals to new areas is not undertaken. While the latest research indicates that development may have opened up new habitats for the UAE’s amphibians, previous studies have found the country’s urbanisation poses a threat to native wildlife such as reptiles.
For example, scientists such as Prof Carranza reported last year that the Emirati leaf-toed gecko had become severely inbred because its habitat on the east coast of the UAE has shrunk as a result of development. Some heavily urbanised nations, notably Singapore, demonstrate that densely packed human populations and wildlife can live side-by-side.
Singapore is less biodiverse than when construction there began more than two centuries ago, says the Institute of Sustainability Studies, but the country’s green cover is said by the Convention on Biological Diversity to have increased from 36 per cent to 47 per cent of the nation's total land area over the past two decades.
The country’s areas of remaining forest are home to 1,190 vascular plant species, 207 bird species, 72 reptile species and 44 mammal species, as well as many freshwater fish, butterflies and other insects.
