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Cave Hill Ecologists Tackle Species Invasions in Barbados

08 June 2023

The University of the West Indies Cave Hill Campus celebrated World Environment Day on June 5^th with a lecture on the interventions needed to control the invasions of flatworms, lionfish and sun corals in Barbados.     
The public event entitled ‘Fighting off the invaders: How UWI ecologists are helping tackle species invasions’ was held in recognition of this year’s 60^th anniversary campus celebrations and hosted by the Department of Biological and Chemical Sciences in the Faculty of Science and Technology.      

Conservative Ecology expert and Director of the Barbados Sea Turtle Project, Professor Julia Horrocks, provided an overview of invasive alien species, which are non-native species that have negative impacts on native species, economies and public health.  She highlighted that many are now familiar to Barbadians, like the mongoose and the casuarina, but are not part of the native fauna and flora.  As a result, these species have had significant negative impacts on native biodiversity.    

Professor Horrocks also detailed the roles lecturers at The UWI are currently playing, to assist the Government of Barbados with prevention of new unwanted species, as well as managing those that are already present.  In particular, she spoke about the appointed Working Group on Biodiversity (WGB), which comprise UWI researchers and focuses on terrestrial and marine biodiversity.         

The work of the WGB includes reviews of import applications to prevent the importation of any species that are likely to become invasive and provides technical advice on policy and legislative controls.  The WGB also assists the Government with its GEF-funded pilot projects, which are supported by a multi-million dollar USD grant to the Governments of Barbados and the OECS to control the impacts of Invasive Alien Species (IAS) on native species of the region.    

If habitats can be cleared of invasive species that prey on or compete with native species, this can allow native species to thrive.  In this context, Professor Horrocks spoke about the highly acclaimed work of UWI alumna Shanna Challenger.  The Cave Hill ecology graduate researched the restoration of the small Caribbean island of Redonda, where rats and goats who had preyed on the native fauna and destroyed the vegetation were removed, allowing the native species to recover.

The Mainland Island Project

With no offshore island isolated enough to prevent re-incursion of invasive species, one of the Barbados pilot projects is to create a “mainland island” – known as a biosecure area – for the leaf-toed gecko.
This gecko is only found in Barbados and was thought to be extinct until 2011.  Mr. Connor Blades (UWI MPhil student) demonstrated how the gecko’s distribution is limited to small areas of habitat, largely along the south-east coast of Barbados, which is likely due to the impacts of invasive species. The fencing of the biosecure area is designed to prevent species that may prey on or compete with the leaf-toed gecko for food and refuge sites, thereby giving the gecko a chance to thrive.     
 
Dr Darren Browne followed with a presentation on the results of his research on flatworms, beginning with initial surveys by undergraduate student, Renisha Wilson, followed by an ongoing citizen science project in collaboration with the Ministry of Agriculture and Food Security and the Ministry of Environment and National Beautification.

He pointed out the dangers these worms can pose to earthworms in particular, which are essential organisms in the maintenance of healthy soil structure and therefore to food production.  He also highlighted the potential public health risk and demonstrated how widespread they are in Christ Church and will likely spread to areas with favourable habitat characteristics like St George and St Thomas.  Dr Browne also gave a cautionary warning about the practice of moving top soil from one part of the island to another, as this is thought to be the primary factor facilitating their spread.     

Senior Lecturer in Ecology Dr Henri Vallès presented on his involvement in one of the GEF-funded pilot projects on marine invasives with specific focus on the lionfish.  The lionfish is a much feared invasive in the wider Caribbean region, and so its imminent arrival raised the prospect of more damage to the Barbados’ coral reef ecosystems and fisher livelihoods.

He gave a historical summary of the spread of lionfish across the Caribbean over a 20-year period. Dr Valles also confirmed that by the time the lionfish arrived in Barbados in 2011, a study was already designed to measure its impact on reef fish communities and fisher catches.  He also presented the findings of the study, which involved comparing reef fish abundance and fisher catches at several sites before and after the lionfish became established in Barbados.

In contrast to what was expected, the study concluded that there was no evidence that lionfish has had any negative effects on native fish communities or fisher catches in Barbados. The study also found that lionfish abundance on the reefs is generally low, most likely because it is heavily targeted by both commercial and recreational spear-fishers. Dr Vallès therefore recommended that spear-fishers continue targeting lionfish to possibly reduce fishing pressure on native fishes.

Dr Vallès also discussed the invasive sun corals - a group of attractive corals with large polyps and yellow-orange tentacles. They are often found on submerged artificial structures such as shipwrecks and piers and were first detected in Barbados in 2010.  In Brazil, they have become a nuisance because they can displace native benthic organisms.

In Barbados, Robert Bourne, one of Dr Vallès’ graduate students, recently conducted a coast-wide survey of artificial structures to assess colonization by sun corals.  This survey confirmed that sun corals were indeed present in most artificial structures.  Mr Bourne also conducted a sun coral removal experiment on a shipwreck to evaluate the length of time it takes for the sun corals to re-colonize the cleared area.  Results revealed that once the area was cleared of sun corals, it took a significant time for them to return indicating that if needed, manual removal by scrapping could be a cost-effective measure to control their abundance on artificial structures.   
 From Left: Ecology Coordinator & Senior Lecturer in Ecology Dr. Henri Vallès; Biology Coordinator & Lecturer in Biology Dr. Darren Browne; and Director of the Barbados Sea Turtle Project & Professor of Conservation Ecology Professor Julia Horrocks engage with the audience on best practices to tackle species invasion.

For further information about the Department of Biological and Chemical Sciences visit: www.cavehill.uwi.edu/fst/bcs/home

For further information about upcoming 60th anniversary events at the Cave Hill Campus visit: www.cavehill.uwi.edu/diamondjubilee/home

   



 
 

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