Image Credit: Alexandre Roux, CC BY-NC-SA 2.0, Image Cropped
In the summer of 2019 I spent a week driving around south-east Norway with my Master’s student Bastian. The plan was to speak to local freshwater managers and get their take on invasive fish species in Norway. I’d never conducted this sort of research before, but I thought I knew what I was in for. Invasive bad, native good, right? More nuanced approaches are for those who are disconnected from the problem, academics like me who could watch from a distance and comment airily.
First interview. What does the term “invasive species” mean to you?
Obviously I expected some combination of “alien to the region”, “brandishes halberds and horned helmets” and “outcompetes the native trout” (trout and its fellow salmonids are really quite popular here). What I got instead (abridged) was a contemplative shrug and a reminder that there are almost no native populations of trout left anywhere in Norway.
Insert confused ecologist.
Economic costs of biological invasions in the United Kingdom (2021) Cuthbert et al., NeoBiota, https://doi.org/10.3897/neobiota.67.59743
I write near constantly about non-native species on Ecology for the Masses, but I mainly focus on the negative impacts that many of them have on native ecosystems. Yet often if we want to really kick off initiatives to manage invasive non-native species, we need to point out the financial burden that many of them bring.
Yet obtaining a simple monetary estimate for invasive species is not easy. A few particularly notorious invasives tend to take up a lot of research focus, which mean that there are many species out there for which our cost estimates could be unreliable. Likewise, we’re likely to have a better picture of the impact of non-native species which have been established longer than ones who have just arrived, and haven’t been sufficiently studied or haven’t spread far enough to have had a measurable impact.
But non-native species aren’t slowing down in their spread anytime soon, so it’s important to figure out what the costs of invasive non-native have been and will be, as well as where there are holes in our knowledge that need to be filled. That’s what today’s study set out to do, by looking at invasive species in the United Kingdom.
A mob of feral horses at Yarangobilly, Australia (Image Credit: Ian Sanderson, CC BY-NC 2.0, Image Cropped)
Horses are, without a doubt, a hugely significant part of human culture and history. Worldwide, they’ve played the role of food source, beast of burden, war steed, postal service, transport, and in modern times pet and sports star. Horses were and in many places still are are an omnipresent part of life. People have a lot of feelings about them.
Image Credit: Paresh Poriya, CC BY 4.0, Image Cropped (also not featuring tunicates)
Testing ecological theories in the Anthropocene: alteration of succession by an invasive marine species (2021) Christianson et al., Ecosphere, https://doi.org/10.1002/ecs2.3471
Ecological disturbances, such as fire, floods, or storms, might seem like a catastrophe at first glance, but often they open up space for new species to take the place of dominant ones, creating a more diverse ecosystem. When a disturbance occurs matters as well – if a storm hits right before a particular species starts to reproduce, that species could take advantage of the extra space and become dominant in a short time.
In the 1970s, John Sutherland and Ronald Karlson tested this theory, looking at the invertebrate community of a coastal dock in North Carolina, USA. They found that which species dominated depended on when the community began to grow (a proxy for when disturbance opened up new space).
The area has since seen the introduction of an invasive species of tunicate, Clavelina oblonga. This week’s authors wanted to test whether the original patterns seen in the 1970s still showed up in the presence of the invader.
Image Credit: Ted, CC BY-SA 2.0, Image Cropped
Invader-pollinator paradox: Invasive goldenrods benefit from large-size pollinators (2021) Moroń, et al., Diversity and Distributions, https://doi.org/10.1111/ddi.13221
A plant that invades a new part of the world can’t necessarily bring its regular pollinators along with it. So it stands to reason that plants who successfully invade a new area receives pollination from native pollinators. Seems pretty straightforward, right?
Image Credit: Bernard Dupont, CC BY-SA 2.0, Image Cropped
Projecting the continental accumulation of alien species through to 2050 (2020) Seebens at al., Global Change Biology, DOI: 10.1111/gcb.15333
A by-product of globalisation is that over the coming decades, no matter how many episodes of Border Patrol get recorded, new species are going to find their way into new habitats and potentially become invasive alien species, exerting negative effects on the locals. We’ve seen this in the past, and I’ve beaten many a dead horse writing about these species on this site.
What this paper set out to find is whether or not we can predict at what scale this trend will increase.
Image Credit: Birgit, Pixabay Licence, Image Cropped
The potential current distribution of the coypu (Myocastor coypus) in Europe and climate change induced shifts in the near future (2020) Schertler et al., NeoBiota, https://doi.org/10.3897/neobiota.58.33118
For all my talk on not immediately demonising alien species, there are a plethora of annoying little critters who the label ‘invasive’ was made for. This is the case with the Coypu, an annoying beaver-like rodent initially from South America who has since spread through other parts of the world, including large swathes of Europe.
The Coypu is a textbook invader – it reproduces quickly, and though individuals don’t stray far from rivers, as a species they are capable of expanding their range very quickly. They destabilise riverbanks through their burrowing, which can lead to severe ecological and economical damage.
They are, however, quite sensitive to temperature, and as such it’s important to know what the effects of climate change will have on their distribution. Today’s authors set out to come up with a habitat suitability map for the Coypu in light of the rise in temperature we’re expecting in the coming decades.
The Burmese python, which has spread throughout the Everglades in Florida as a result of accidental or intentional releases by pet owners (Image Credit: US NInvaders, Aliens, and tational Park Service, Public Domain Mark 1.0, Image Cropped)
Language is important. It’s a lesson many biological scientists would have learned a long time ago if we hadn’t kept social sciences at such a wary arm’s length. Ecologists have a tendency to label and relabel ecological concepts (anyone up for a debate about the word ‘niche’?), species and even global phenomena (think global warming vs. climate change) based on anything from shifts in public perception to new findings that challenge our earlier labels.
I sat down with leader of the UK Ladybirds Survey Helen Roy to talk about the stigma surrounding invasive species like this Harlequin Ladybird (Image Credit: PJ Taylor, Pixabay Licence, Image Cropped)
While climate change and habitat loss seem to keep making all the headlines when it comes to environmental damage, invasive species are still chugging along comfortably as the second biggest threat to our planet’s biodiversity. New cases are popping up all the time, with the Burmese python, Crucian carp and the emerald ash borer beetle recently reaching new levels of notoriety.
Yet the negative impact that many non-native species have on the habitats they move into have often led to stigmatisation of anything new. This can be counter-productive, as the majority of newcomers into an ecosystem won’t have a pronounced negative effect. And whilst it may seem like a smart piece of preventative management to maintain an ecosystem’s status quo by preventing species introductions, it’s often just not feasible.
With this in mind, I sat down at the recent British Ecological Society’s Annual Meeting with Professor Helen Roy of the UK Centre for Ecology and Hydrology. Helen has studied the impacts of non-native species the world over, from the UK to smaller island nations like St. Helena, and has led several projects for the European Commission on non-native species. We spoke about the importance of distinguishing between invasives and non-natives, the impact of climate change on invasive biology, and the social and cultural significance of both native and non-native species.
Image Credit: California Department of Fish and Wildlife, CC BY 2.0, Image Cropped
Angling as a source of non-native freshwater fish: a European review (2019) Carpio, De Miguel, Oteros, Hillstrom & Tortosa, Biological Invasions, doi.org/10.1007/s10530-019-02042-5
People love fishing. It’s an intrinsic part of some people’s lives, whether as a livelihood or a past-time. People who have grown up fishing often have specific species that they enjoy fishing for. Nothing wrong with that.
Yet people’s desire to go after one fish species will often lead them to move that species around. This can happen on a small scale, with people moving a species from one lake to another slightly closer to their homes. Or it can happen on a massive one, with a species being transported to new continents.
This has shaped entire freshwater communities in modern-day Europe, where 195 species now reside that have no natural range in the continent. Most of these have been introduced since the nineteenth century, which is around the time that fishing became a popular recreational activity. This week’s authors wanted to find out what the role of recreational fishing was in shaping the make-up of today’s invasive freshwater fish populations in Europe.