Unravelling the ecology of invasive species: from individuals to communities

Professor Helen Roy presents on the ecology of invasive species and the role of citizen science.

This presentation was given at the Faculty of Veterinary and Livestock Sciences, University of Chile.


 

Presentation Transcription

 

Climate and invasion = deadly duo? | Slide two 

The number of non-native species arriving in new regions is growing. Over time, there is a rapid escalation in the number of new arrivals.
When talking about non-native species, I mean those species that have been introduced by humans, while invasive non-native species refers to the small proportion that cause some kind of problem. I may also refer to non-native species as alien species. 

Many interacting factors… | Slide three 

There are many interacting factors driving biodiversity change that we need to take into account. Here I present some of the work that we have been doing looking at the trade networks and now they influence the movement of non-native species all around the world. There is no doubt about it that globalised trade and environmental change are likely to be facilitating invasion. 

vary in importance through the invasion process | Slide four:…

Different factors vary in their importance through the invasion process. Here is some work by Regan Early looking at global threats from invasive alien species. Regan shows that there are a whole variety of traits that influence introduction, particularly around the trade movement and import. Then there are a variety of other factors that influence establishment, and that might be to do with habitat, increased agriculture intensification, and in this case, fire as well. 

Hottentot fig… home and away | Slide five 

When we are looking at these non-native species they are really fascinating from an ecological perspective. They are fascinating for a whole variety of reasons, but they are also extremely worrying and costly in terms of the economy and society, and perhaps to my interests more, the cost to biodiversity. Hottentot fig is a really excellent example. Here we compare its native range in South Africa, growing in the sand dune systems [left image] with that of the west of England [right image]. 

The good – bryony ladybird | Slide six 

It is really important to remember that not all non-native species cause problems or are considered to be bad, in fact some of them are celebrated. This is a ladybird, called the bryony ladybird, first seen in the UK in the mid-1990s. The map presented shows it has a very limited distribution, even 20 years on from its arrival. And actually people really quite enjoy seeing it, and it only feeds on white bryony and does not pose a threat in any way at all. 

The bad – Harlequin ladybird | Slide seven

In contrast, the Harlequin ladybird has become a global invader. The data [presented here] for the UK shows that it has spread very rapidly, in the UK spreading at about 100km per year. The reason it is concerning is that It is a voracious predator, it is also a generous predator as it eats a whole range of insects, not just the pest insects for which it was initially introduced to some countries. 

The good and bad – Buddleja davidii | Slide eight

For some species we find it difficult to know if they are good or bad. This is when we begin to see some of the contention arising in the field of invasion ecology. One of these species is Buddleja, which grows very profusely in the UK and in many urban environments. Although it is a fantastic nectar source for pollinating insects but does cause infrastructure problems. 

Differing perspectives | Slide nine

We have different perspectives around these non-native species, and does divide opinion at times. This can be unhelpful because it is clear that certain non-native species pose a threat. Some prioritisation to focus action can help to protect biodiversity. 
Action is not all about protecting native biodiversity is also important for protecting the function of affected eco-systems.  Journalist Fred Pearce, in his book  covers different perspectives and states that ‘invasive species will be nature’s salvation’ because we have caused so much damage to our eco-systems that the only things really thriving are these invasive species and they will carry out the functions 

Countering controversy through communication | Slide ten

I believe it is important to counter controversy related to invasive species through science communication. I have a passion for science communication; talking to newspapers etc. [On-screen] you can see details of a BBC Inside Science radio programme that I appeared on so that Fred Pearce and I could discuss invasive species and weigh-up the evidence between us with respect to the threat they pose and try and unravel some of these controversies. 

Ignoring the complexity… | Slide eleven 

As already mentioned, my big concern is ignoring the complexity, if we make it too simplistic in terms of our interpretation and understanding of the function of species then there is a real danger we will not be protecting the systems we should be protecting. The media has been fantastic at promoting science, but sometimes the complexities and new answers of these ecological systems, which we know are complex, get missed along the way. You can see an example [on screen], both ladybirds are invaders of different places and parts of the world and they are both cannibalistic, but this headline suggests different. 

Need for robust evidence for decision-making | Slide twelve 

It is important because we need robust evidence for decision making, we need to inform policy-makers about what is happening with our environment. We need to be assessing whether or not various mitigation strategies are working to address some of the threats that are posed. With invasive non-native species posing a quoted cost to Europe of around 12 billion Euros per year it is clear there is a need for some effective decision making to bring the cost down, but not just the economic cost but also the cost to biodiversity and society. In the UK we produce these biodiversity indications on an annual basis, and this is a great way to demonstrate the state of nature to our policy-makers. 

GB Non-Native Species Information Portal | Slide thirteen

One of the projects I lead on in the UK is the GB Non-Native Species Information Portal. Essentially we collate information on all non-natives species in Britain and a whole variety of attributes alongside that including their pathways of arrival, when they first arrived, where they first arrived and what kind of functional group they are. We know from this database (which is constantly being updated), that we have 2,000 established non-native species in Britain. By established, I mean the ones that are reproductively active, or having sustained populations within Britain. 

Scorecard 2016 for Great Britain | Slide fourteen 

Every year we produce a score card to summarize this information. [On screen] you can see the scorecard for last year [2016]. We can see just under 2,000 established species in total with plants being the numerically dominant species. Looking at the impacts we can see a very low proportion, 6.6% of plants pose a threat whilst a third of the non-native animals do pose a threat.

Invertebrate invasions over time | Slide fifteen 

I am particularly interested in insects and insect community ecology and we can look at invertebrate invasions overtime and we see a similar figure to one we saw for new arrives within Europe. It’s interesting to see in Britain that one of our first reported invaders was the Blatta orienalis, but some later ones include Vespa velutina

Can we predict invasions? | Slide sixteen 

One of the things we have been thinking about is that, it is good that we document these invasions and produce this database of non-native species, but can we actually predict invasions because this would actually help us or our policy makers in terms of the necessary surveillance to be able to put in measures for prevention. We undertook a consensus workshop, where we gathered experts together across a variety of different groups, and we let them gather as much information and combine this together.  We could then begin to rank species and think about which ones are likely to arrive, establish and spread within the next decade and threaten biodiversity in one way or another. 

Horizon scanning for invasive alien species with the potential to threaten biodiversity in Great Britain | Slide seventeen 

We published the work on global change biology in 2014. It has a long list of co-authors, some of them from our volunteer sectors, the volunteer experts who run some of our recording schemes. There is a whole variety of different people from a variety of backgrounds.

Horizon scanning for invasive alien species with the potential to threaten biodiversity in Great Britain continued | Slide eighteen

We now know that just in the last few years, seven out of the ten species we ranked as being the top threat have now arrived. What it shows is that there are ways we can predict invasions, and now what we need to do is think about how we then use that information to prevent their arrival in one way or another. 

GB Top 10 – Asian hornet | Slide nineteen

One of our top ten species that arrived last September was the Asian hornet. It is a species that originally arrived from Asia into France, a chance event. This has spread rapidly within France, so therefore we anticipated its arrival within Britain. The first records arrived in Britain last September, we are rather hoping they have been eradicated. But we are putting surveillance into place to see and check those sites again and keep our early warning systems running in full force. 

Asian hornet – arrived September 2016 | Slide twenty

One of the things we did when we knew the Asian hornet arrived was creating an app to make it easier for people to report sightings or things they might think about the Asian hornet. This will be particularly important for bee-keepers to use, as the species is fond of eating honey bees.

GB Top 20 – Argentine ant | Slide twenty one 

One of our other species we found within our top twenty was the Argentine ant. We would have put this higher but we feel we need more climate warming for it to survive our winters here. However, I read a paper earlier this week that suggests there is a colony in London that has managed to sustain for a few years. It is thought by moving into buildings for the winters and spreading out afterwards. These ants are a problem because they are what we call eco-system engineers. They can have a profound influence on the eco-systems in which they arrive. Fascinating insects, but really quite a concern once they are spotted.

Arrived in Wales, 2014 | Slide twenty two 

We have marine species on the list also including the Asian shore crab which was one of the first species from our list which was reported in Wales.

Slide twenty three: Arrived near Heathrow, 2014

We had one species which we put at the number one position which was the Dreissena bugensis rostriformis (Quagga mussel). This again is an eco-system engineer, it has really amazing, cascading effects within waterbodies. It is a fantastic filter feeder so it really alters the algal community which then has knock-on effects for other species. It also deposits toxic faeces and results in some negative changes within affected water bodies. 

This is a racoon – isn’t it? | Slide twenty four

The racoon was also on our list. There are racoons in captivity in large numbers across the UK. We knew in Austria and Germany they have had problems with populations building up – they are great escape artists! Not long after the list was published a photo of a racoon in the UK [on screen] was sent in. 

Myriophyllum heterophyllum in 2016 | Slide twenty-five

We also have some freshwater plants on our list. Myriophyllum heterophyllum was one that was spotted last year. It was very difficult to identify and distinguish from some of our native species. 

Alien Alerts | Slide twenty-six 

We have also devised is a system for Alien Alerts where we can encourage people to report their biological records, feed them into a database, get an expert to check out that record, and then feed the information to all the stakeholders that need to know about it and action can be taken.  That action is not necessarily all about eradication, it might be about containment and biosecurity such as the campaign ‘Stop the Spread’.

Informing the new European Regulation | Slide twenty-seven 

Other work I have been leading has been to form a new European Regulation. This European Regulation came into force in 2015 and is really based around the prevention of the arrival of species. It has been really welcomed by many people. 
At the core of this regulation is a list of species that are thought to pose a threat and should have some action around them. Whether it be to do with trade, or action on the ground if they are spotted, but certainly to do with communication between European countries notifying each other what is arriving within their domain. 

Prioritising Pathways | Slide twenty-eight

We have been conducting work to prioritise pathways. We are looking to understand which pathways bring in the most troublesome species, and can we get better at collating this pathway information and understanding how species are getting from one place to another.

Convention on Biological Diversity | Slide twenty-nine 

One of the things we had to do was to harmonise pathway terminology. We produced a terminology based on one from Phil Hume produced. We refined this and produced definitions and published this within the Convention on Biological Diversity (CBD) technical advisory notes.

Mapping Pathways | Slide thirty

This has allowed us to bring together data from a variety of databases and to begin to map pathways. We have used our CBD pathways to map the global invasive species database and also the delivering invasive alien species inventory for Europe database. This allows us to gather the information all together in one place. We’ve just published this paper in the Journal of Applied Ecology, where we are able to look at the different pathways of arrival, whether they be intentional or unintentional at a very crude level. But we can also break that down into the individual pathway seen within that CBD definition and see how that varies between different taxonomic groups and different environments for instance. 

Variation in the importance of pathways | Slide thirty-one

Recently we have published another pathway looking at tackling the pathways of biological invasion. Again looking at, in more detail, what is moving in terms of marine species, freshwater species and terrestrial arthropods. And we can see there are very different patterns between the different systems and taxonomic groups. 

Invasion and wildlife disease | Slide thirty-two

I am really fascinated by parasites and diseases, and I think we often ignore them. But I think we need to begin to think more about wildlife diseases in the context of invasions.  Many of these databases we have documenting our native species don’t include anything on microbes, or if they do, they are limited. I held a workshop through Cost Action where we gathered together a range of experts from different taxonomic and environmental areas, to look at why we were not understanding better invasions and wildlife disease. 

Nature correspondence | Slide thirty-three

We published this as a short correspondence within Nature - Invasive species: Control wildlife pathogens too

Conservation letters | Slide thirty-four

We also published on the topic in Conservation Letters on the topic. 

COST Action: ALIEN Challenge | Slide thirty-five

The COST Action has had many meetings; short term scientific missions where people have traveled around the world to work in other labs and gain other experiences; we have run training schools around marine identification or around distribution modelling; and held workshops to understand social and economic impacts of alien species. 

Future directions: global collaborations… | Slide thirty-six 

What are our future directions? Well, I am here in Chile, working together on Harmonia axyridis in particular but we are very interested in citizen science and its applicability to other systems in particular with invasion biology. I have also been working with people in Eastern Europe because it is really interesting to try and understand some of these systems along spatial gradients and understand why we see differences and what are the similarities. 

Citizen Science and alien species | Slide thirty-seven

I have already mentioned that I am interested in using Citizen Science to help us understand alien species ecology, and also help with surveillance and monitoring for example. Again I was delighted to be involved in this collaboration where we looked at what variables we should be monitoring globally to understand biological invasions on a global scale. And it was really seen that countries capitalising on citizen science as well as emerging online and remote technologies and data capture would really improve our understanding of invasion ecology.

Citizen Science and alien species continued | Slide thirty-eight 

We have published a few things from this. There is a paper out, but we also published a guide to citizen science, which you can see on screen, which goes into more detail in a more accessible way. 

Citizen Science and alien species continued | Slide thirty nine 

Last summer I had the pleasure of leading a workshop in East Africa with the Tropical Biological Association (TBA), funded by The British Ecological Society and also my own organization and the TBA. We looked at citizen science, and came up with some priorities, opportunities and barriers to citizen science.  We are very excited to be running something similar in Chile, and it will be really interesting to make comparisons between different places in terms of what we can learn from one another, so that we can more effectively deliver this large-scale citizen science projects to address these big ecological questions we want to be addressing. 

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