Tag Archives: invasive
This article was first published in late 2018 (Image Credit: Mallee Catchment Management Authority, CC BY-SA 4.0, Image Cropped)
When a food source provides almost half a planet with protein, you can expect the people who deliver that food source to play an important role in society. Fishing is no exception. Any country that has a marine or freshwater ecosystem in close proximity will have a fishing community, and that community can play a variety of roles, from something as simple as putting food on people’s tables to campaigning heavily to keep your country from joining the EU.
So it makes sense that fishers should have access to good fish science, at every level. If you’re a multi-million-dollar corporation, you need to know how fish stocks will respond to certain catch levels over a sustained period. If you’re a local or specialised fishing community, you need to know how available your catch will be in five years given temperature increases. And if you’re one person on a boat in a river, you might want to know how best to treat an over- or under-sized fish to ensure it survives being released.
It follows, then, that there should be open communication between fish scientists and fishers. At this year’s Australian Society of Fish Biology conference, I asked a variety of delegates a simple question: Is there open communication?
Guest post by Paula Tierney
Invasive freshwater fish (Leuciscus leuciscus) acts as a sink for a parasite of native brown trout Salmo trutta (2020) Tierney et al. Biological Invasions. https://doi.org/10.1007/s10530-020-02253-1
From house cats to cane toads, invasive species are one of the biggest threats worldwide to native plants and wildlife, second only to habitat destruction. There are a few different definitions of an invasive species, but two consistent tenets are a) that they are a living organism spreading and forming new populations outside of their native range and b) causing some kind of damage to the native ecosystem, economy or human health. As humans move around the globe with increasing ease (these last two months aside), the spreading of invasive species is increasingly common in our globalised world.
The spread of invasive species creates new ecological interactions between native and invasive species that can impact how our native ecosystems function, including disease dynamics. One key set of interactions that can be completely changed by the introduction of the invader are that of parasites and their hosts. If development and transmission of native parasites is different in invasive hosts compared to their usual native hosts, the parasite dynamics of the whole system can be altered.
Introduced herbivores restore Late Pleistocene ecological functions (2020) Lundgren et al., PNAS, https://doi.org/10.1073/pnas.1915769117
The fauna of the Pleistocene (also known as the Ice Age) was not that dissimilar to the communities of animals which inhabit our planet now. However, many more large land mammals inhabited all kinds of ecosystems. By the end of the Pleistocene, many of them were extinct, mainly due to climate change impacts (glaciers got larger and restricted their ragne) and prehistoric human impacts like over-hunting, habitat alteration, and introduction of new diseases. The decline of large-bodied herbivores in the Late Pleistocene (LP from here on) led to many ecological changes including reduced nutrient cycling and dispersal, reduced primary productivity, increased wildfire frequency and intensity, and altered vegetation structure. These changes have become our norm.
Scientists usually study species introduction under the premise that they are ecologically novel. However, the introduction of large herbivores has been found to drive changes in the environment, potentially restoring or introducing novel ecological functions similar to pre-extinction Late Pleistocene conditions. This week’s researchers wanted to investigate what sort of role introduced mammals played in restoring ecological interactions by investigating their functional similarity with LP species.
My lord Iceland is gorgeous. There could not have been a better setting for the 2020 Nordic Oikos Society’s Annual Meeting. Driving through deserts of snow that ring of the kind of quiet isolation you’d expect from a town in a depressing British murder mystery was a wonderful experience.
As was the conference itself, of course. So let’s recap some of my highlights from this year’s meeting, titled ‘Ecology in the Anthropocene’.
Image Credit: The Witcher, 2020
Science and movies often don’t go well together*. It’s no-one’s fault. Science can often be boring and riddled with uncertainties, and movies and TV require plot advancement and definitive results.
But you know what’s a scientific fact? That Henry Cavill’s chin can cut diamond, and if you thrust him into a cosplay outift he probably already had at home and send him out to slaughter a bunch of CGI monsters you’ll get something that is at the very least mildly enjoyable. And if you’re an invasion ecologist who runs a podcast looking at the ecology of movie monsters, mildly enjoyable monsters are enough to dedicate a blog post to.
Invasion of freshwater ecosystems is promoted by network connectivity to hotspots of human activity (2019) Chapman et al., Global Ecology and Biogeography, https://doi.org/10.1111/geb.13051
The spread of invasive species throughout freshwater ecosystems is a topic we’ve looked at before on Ecology for the Masses. In a previous paper breakdown we talked about how recreational is heavily responsible for the presence of non-native fish at a European scale.
Our paper this week takes a more local approach. Can we predict the presence of non-native birds, invertebrates and fish by looking at the presence of human activity, and where that human activity is present?
I am completely exhausted as I write this. I’ve just flown back into Norway after spending the week in Belfast at the British Ecological Society’s annual meeting. And whilst I do love attending conferences, after any mental onslaught of information it’s probably a good idea to take a day or two off to relax and let it soak in.
But before I run off on holidays to do that, let’s have a look at some of the most noteworthy points from BES 2019. I’ll touch on the words of some of the plenary speakers, the general atmosphere and I will try MY ABSOLUTE HARDEST not to talk about British politics.
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.
When we think of global warming, we tend to be a bit selfish and think of how it affects us in our daily lives, but the warming temperatures on our planet have the potential to affect the base of all of our food webs, plants (Image Credit: Matt Lavin, CC BY-SA 2.0).
Phenology in a warming world: differences between native and non-native plant species (2019) Zettlemoyer et al., Ecology Letters, https://dx.doi.org/10.1111/ele.13290
The timing of life-history events (such as births, growing seasons, or reproductive period) is called “phenology”, and this aspect of an organism’s life is particularly sensitive to climate change. So much so that changes in the phenology of certain processes are often used as an indicator of climate change and how it affects a given organism.
We’ve talked about the effects of rising temperatures in animals here on Ecology for the Masses, but there is a lot of evidence in the scientific literature for climate change causing a multitude of different changes in the phenology of various plants. Not only does the direction of the change differ (some organisms experience delays in certain events, others have earlier starts), but the size, or magnitude, of the change also differs. The authors of today’s study wanted to examine these changes in the context of an invasive plant species and how it may be able to outcompete a native plant.