Category Archives: Invasive Species

Fishing for Invaders

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

The Crux

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.

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Our Responsibility Regarding Invasive Species (A Counterpoint to Mark Davis)

The Eastern Oyster, a species which has a high potential to spread throughout Norwegian waters, but little known ecological effect (Image Credit: James St. John, CC BY 2.0, Image Cropped)

Last week I posted an interview with Mark Davis, an invasion ecologist who has urged caution when rushing to eliminate invasive species from an ecosystem. Whilst I didn’t agree with absolutely everything Mark said, he makes some very important points about the language around invasive species and our understanding of them.

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Between a Dam and a Hard Place

Dams like this change the flow regimes of rivers, and prevent some species from accessing their spawning grounds, lowering population viability. But is removing them completely danger-free? (Image Credit: Notorious4Life, CC0 1.0, Image Cropped)

Anybody who has ever studied freshwater ecosystems will end up having to study dams at some point. And they’ll no doubt learn that dams are the enemy. They fragment ecosystems. They cut fish off from their spawning grounds. They change flow regimes. So it makes sense that the recent trend of dam removal across Europe and the world in general would please ecologists. But there’s a problem with dam removal, and it comes in the form of invasive species.

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Invasive Species and Climate Change

The next 50 years will see parts of the planet warm significantly. So how does this impact invasive species?

Image Credit: TheDigitalArtist, Pixabay licence, Image Cropped

In this series, we’ve looked mostly at species that have been introduced at defined points in time. The Pink Salmon and the Red King Crab were introduced into Russian waters near Norway in the 50s, the Canada Goose was brought to Europe in the 30s, the Sitka Spruce in the late 1800s. But with the onset of climate change, warmer conditions in the Arctic and sub-Arctic mean that the doors will open for more gradual arrivals. So let’s look at how climate change will facilitate the arrival of these newcomers.

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In Defense of Aliens

It's important to remember that not all alien species are harmful, and we shouldn't treat them all as such

Image Credit: Lou133lou133, CC BY-SA 4.0, Image Cropped

Building on last week’s article on defining invasive and alien species as well as the work of Professor Mark Davis, I am going to do the unimaginable for an ecologist and argue that maybe alien species aren’t always a bad thing. I want to emphasize that maintaining biodiversity is essential, but maybe we should focus on the role of species in their environment rather than their place of origin.

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Defining an Invader

The Northern Pike. Although it's native to Norway, it has been moved around since and is now classified as 'regionally invasive'.

The Northern Pike. Although it’s native to Norway, it has been moved around since and is now classified as ‘regionally invasive’. (Image Credit: Jik jik, CC BY-SA 2.0)

Two weeks ago, Norwegian Science Institute Artsdatabanken (ADB) announced that they would be changing the name of their invasive and alien species index. Formerly known as the Black List, the institute decided to use a name with less negative connotations, “Fremmedartslista“, loosely translated, the Alien Species list. Given this series’ focus on species from that list, it seems like an appropriate time to look at how we define the terms ‘alien’ or ‘invasive’ species.

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