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.
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: Neil Hammerschlag, Oregon State University, Image Cropped, CC BY-SA 2.0
Ecosystem Function and Services of Aquatic Predators in the Anthropocene (2019) Hammerschalg et al., Trends in Ecology and Evolution, https://doi.org/10.106/j.tree.2019.01.001
Aquatic predators play an important role in many ecosystems, and are often among the more charismatic species in the ecosystem. Because of this, they are often the target of conservation for ocean management bodies worldwide. This paper aims to provide a synthesis of the ecosystem services that aquatic predators provide in marine and freshwater ecosystems worldwide. Below, we’ve chosen 4 of the more interesting and important roles to go into.
Image Credit: Attack the Block, 2011
We examine the ecology of the BGWMs of 2011’s Attack the Block. Sexual ecology has never been more furry. Or glow-in-the-dark. Actually sexual ecology can get pretty furry. Also we have two fights this week.
3:05 – The Chimera in Cinema
11:41 – Ecology of a BGWM
38:38 – BGWMs vs. Liam Neeson from The Grey
You can also find us on iTunes and Google Play.
Spreading of the Australian yabby has led to decreases in other local species. But what happens when these species meet? (Image Credit: Daiju Azuma, CC BY-SA 2.5, Image Cropped)
Insight into invasion: Interactions between a critically endangered and invasive cray fish (2018) Lopez et al., Austral Ecology, doi:10.1111/aec.12654
When we talk about invasive species, often the first thing that pops into our minds are things like feral cats, wild pigs, vicious newcomers that wipe out species or transform vast areas. But often what we focus on less are species which arrive and simply outcompete the locals.
The yabby (Cherax destructor) is one such invader. An Australian species, it has been introduced to new waterways through the country and is now threatening other species, including the Falls Spiny Crayfish (Euastacus dharawalus) in eastern New South Wales, Australia. The introduction of the yabby has resulted in a decreasing habitat range for the crayfish, but what sort of mechanisms are causing this? This experiment aimed to document interactions between the two species.
The Japanese skeleton shrimp is responsible for the reduction of many Norwegian local species who flee in terror because LOOK AT IT (Image Credit: Erling Svensen, CC BY 4.0)
Today’s creatures look horrific. Or they would, at least, if they weren’t so tiny. A long-range invader, the Japanese skeleton shrimp (Caprella mutica) is tiny, but their ability to colonise new areas quickly has made them a problem for other aquatic invertebrates since their first sighting in Norway 20 years ago.
The Lake Trout, the species which was almost driven to extinction by overfishing and Sea Lamprey invasion, has now been restored in the Great Lakes (Image Credit: Cory Goldsworthy, MDNR, CC BY 2.0, Image Cropped)
Back in June this year, I was fortunate enough to attend the 9th International Charr Symposium, a conference which takes place every three to four years focusing on fish in the genus Salvelinus. The conference took place on Lake Superior, a site where the local Lake Trout population had previously been greatly reduced by overfishing and the invasion of the Sea Lamprey in the first half of the 20th century.
Yet the concerted efforts of the State, Provincial and Federal governments’ Fisheries Departments from the U.S. and Canada worked to successfully control the invasive Sea Lamprey species, and the native Lake Trout population was restored. I spoke with Don Pereira, Don Schreiner and Cory Goldsworthy of the Minnesota Department of Natural Resources (MNDNR) and Minnesota Sea Grant (MNSG) about one of the rare success stories of invasion ecology.
In the series Norway’s Newcomers, we’ve looked extensively at not only Norway’s non-native species, but the genetics, definition and even the defense of alien species. So it made sense that we’d eventually find our way to interviewing an invasion biologist. I was in St. Paul, Minnesota earlier this year and was lucky enough to sit down with Professor Mark Davis.
Mark has been a strong opponent of the demonisation of invasive species for decades. Whilst many ecologists’ first reaction is to eradicate any non-native species, Mark has urged caution, and encouraged the community towards less pejorative terms. I spoke with Mark about the impact our work has on public opinion, how we should talk about non-natives, and living with the impact of invasive species going forward.