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Potentially invasive species located and ‘scored’ in Horizon scanning


A conference including experts from Gibraltar, the UK and different parts of the EU on Horizon Scanning for invasive species recently took place on the Rock.

The aim of the event was to help identify potential invasive species that could affect Gibraltar’s terrestrial and marine environment.

There were over 25 people taking part in the course including local scientists from the Department of the Environment, the Gibraltar Botanic Gardens, the Gibraltar Ornithological and Natural History Society and the University of Gibraltar.

Invasive non-native species are considered one of the greatest threats to biodiversity given their potential impacts on protected species and habitats.

Professor Helen Roy from the UK’s Centre for Ecology and Hydrology is the Project leader and Principal Scientist. She worked together with Stephen Warr from the Department of Environment and Climate Change at the conference.

Together they told the Chronicle what the conference had achieved so far, with a lot of work still to come.

Horizon scanning aims to predict what could possibly happen in the future, Professor Roy explained.

“We have such fantastic information from around the world on species that have invaded other areas that gives us a very good starting point,” Professor Roy said.

“We can do climate matching, habitat matching and see what are the similarities between here and other parts of the world.”

“We can also think about the main way in which species can arrive here and the connections Gibraltar has to other parts of the world, its proximity to Morocco and to Spain.”

Species that have already arrived in Spain could very well arrive in Gibraltar. The scanning is like detective work describes Professor Roy who credits the “amazing group of experts who have a deep ecological understanding and such breadth of knowledge across this taxonomy groups, good access to databases and literature.”

Combined they all work hard to think of all the possibilities.

This Horizon Scanning project is part of a UK Government funded project that is looking across all of the 16 UK overseas territories, with the Gibraltar conference being the 15 Horizon Scanning to take place by the team in the last nine months.

“What has been amazing is not just the discussions we have had at these but also the experts that we meet in all of these different places,” said Professor Roy.

She added it helps widen their knowledge and methods of attaining and utilising information.
This is the first formal Horizon Scanning for Gibraltar, Mr Warr told the Chronicle.

“We have done assessments before, GONHS did as part of their biodiversity action plan for example,” he said.

“This was done over ten years ago and they looked at the species that were already affecting Gibraltar. They did mention some species that could be coming but not to the extent that we are doing now.”

“When we talk about Horizon Scanning we are looking at lists of over 100 species that could potentially affect the terrestrial environment and on the marine front we looked at over 50 species.”

With each list, the group see what literature there is already out there, seeking information such as numbers or speed at what it might spread.

The group then decide which species are the ones that raise the most concern.

“We then go to a scoring process,” said Professor Roy.

“It’s a crude scoring process where we think about what is the probability of the arrival of the species, what is the probability if it arrives and establishes with reproductive capabilities and if it can establish then what is the probability of it having an impact.”

“Then we score for three different impact categories, we look at effects on biodiversity systems, effects on human health and effects on the economy,” she added.

During the first two days of the conference the group went through the list and the scoring process for 230 species. Of these 230 species the group identified 57 that they consider to be a significant threat that they will go into them in more detail. This is in terms of the pathway in which they can arrive here in Gibraltar.

“We are working through the pathway action planning to think about like ok we know we have these different types of mosquitos could potentially arrive. What can we do about that? What would we do to try and offset their arrival,” said Professor Roy.

Not that much can be done to offset their arrival especially if it is a marine based invasive species.

“In terms of stopping them, I don’t think you really can, particularly on the marine front. You can’t stop marine currants for example,” said Mr Warr.

“One of the things that we can do is in the case of ballast water or other discharges from ships that is something we can look into. Which we are looking into,” he added.



Professor Roy and Mr Warr explain that invasive species in the marine environment is a problem as the water is so connected and species can travel vast distances.

Professor Roy believes if there was more of a culture of ships and vessels cleaning their hulls and the need for a certification that states they have done so and are not carrying “hitchikers” would help.

Plus if ballast water was discharged way out to sea rather than the Bay area then any marine organisms included in the water are unlikely to go somewhere.

She believes that these measures need to be adhered to globally.

It is not just the marine environment where it can hard to get rid of an invasive species this happens in the terrestrial environment too, giving the example of insects and how difficult it might be to irradiate them.

“For some of the vertebrates it is a bit easier because they are large charismatic species but they can come along with their problems as well,” said Professor Roy.

“Some of these species some people may begin to like seeing them around for example parquets are very beautiful animals and there can be some negativity around the idea of controlling them. I think it is most definitely in ecology an issue where it is extremely important to be working with people raising awareness.”

Not all invasive species will cause problems, but for the small fraction that does plans need to be made regarding how they are handled.

One way to control and help the environment regarding invasive plants, gardeners and horticultural companies will be provided with a list of plants they should not bring into Gibraltar, even if it is not in law.

Mr Warr credits the public for providing information regarding species they see.

Often the departments get phone calls regarding various species that he or any of his fellow colleagues may not have known about. This helps built up the picture of what is happening to the marine and terrestrial environment.

“It’s about being proactive, there might be species we don’t know about but a member of the public has seen,” he said.

Professor Roy added: “People can play an important part in early warnings regarding detection but also in prevention in terms of when they go to somewhere else in the world they are not bringing species back.”

“I think it is important for people to know that there are many non-native species that don’t cause any problems so we need to focus on this small proportion that do cause problems.”

With some of the species contingency planning is possible with other it is not and it is a case of monitoring and surveillance as well as raising awareness while trying to reduce the chances of their arrival.

The list of 57 species that could potentially affect Gibraltar will be published in due course alongside visuals and information. In addition, a report on the whole project will be prepared and submitted for peer review.

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