Tag Archives: invasive
Lake Superior, the location of the 9th International Charr Symposium (Image Credit: Wikipedia Commons)
This week I’ve been lucky enough to represent NTNU at the 9th International Charr Symposium in Duluth, Minnesota, a conference focussing on one of my focal species in the genus Salvelinus. Conferences are like this are great for soaking in a swathe of alternative perspectives, so I thought I’d share a few thoughts from day one of the symposium, including a sign of success, one of innovation, and another of hope.
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.
The European Perch, brought for angling by earlier settlers, has had severe effects on a number of native Australian fish (Image Credit: Wikipedia Commons)
Transport pathways shape the biogeography of alien freshwater fishes in Australia (2018) Garcia-Diaz et al., Biodiversity Research, DOI: 10.1111/ddi.12777
Invasive species are a problem in every type of ecosystem, be it by reduction of local diversity, or negative effects on a region’s economy or human health. Freshwater rivers and lakes are no exceptions to this. Invasive fish have impacts on local habitats which include outcompeting or just flat out eating local species, changing a habitat’s entire structure (say by clearing away aquatic vegetation or increasing pH levels) and the reorganisation of the entire population of a lake or river, from the birds that nest on the shoreline to the tiny planktonic species that are the base food source of the entire ecosystem. Once an invasive species is established, it can be impossible to remove.
So naturally, understanding where and how invasive species are likely to strike is of huge benefit. This paper tries to map that out, using Australia as a case study. It’s a great example; Australia has a long history with invasive species, and this study alone looks at 33 different types of invasive fish.
The Sitka Spruce was introduced by the timber industry, and now covers almost 5 million hectares in Norway (Image Credit: Paul Harald Pedersen, Fylkesmannen in Nord-Trøndelag, CC BY 4.0 )Tanja Petersen