I was reminded this week that trout in New Zealand rivers are introduced predators and that this is not good for some native fish.

I was up in the mountains at Craigieburn Forest Park on Thursday (scoping out a new university ecology field trip). One of our team thought she saw a trout in Cave Stream, and I got a quick photo.

We were with retired forester Nick Ledgard, who spent much of his career working here. He had seen native galaxid fish in the stream before and thought it was trout free, since trout would have difficulty getting up past the cave system that Cave Stream is known for.

Looking at my photo later, I unfortunately confirmed that it was a brown trout.

NZers love trout and trout management is an important way to advocate for cleaner rivers. Still, it is also important for native fish conservation (especially non-migratory galaxid fish) that some stretches of our rivers remain trout free.

http://inaturalist.nz/observations/328459396

#fish #nz #BiologicalInvasions #trout

Tonight our teenage daughter asked if we could rewatch the old Cane Toad documentary, An Unnatural History. We’d played it for her when she was much younger and it had stuck with her. It’s still a cracker documentary, in equal measures informative and alarming and hilarious. One of the best. Also, it ends with a theme song written and sung by Tim Finn of Split Enz and Crowded House fame.

Worth a watch if you’ve not seen it.

https://www.youtube.com/watch?v=aZgm9yiGzEE

#CaneToads #NatureDocumentary #Australia #BiologicalInvasions

Huifei Jin et al. test the separate and combined effects of nutrient levels and nematodes on performance of individual invasive plant species, as well as their competition with native plant communities.

#BiologicalInvasions | #Exotic_nativeCompetition | #GlobalChange | #Nematode_plantInteractions | #ResourceAllocation

https://doi.org/10.1093/jpe/rtaf060

The American ragwort aphid is now up in the Christchurch Port Hills where it's feeding on native senecio plants. 😔

The species arrived in the city in autumn of 2019 and has been spreading since then. I found it last week on the top of Sugarloaf, which is the first record of the species in the hills beyond the city.

Things are going to get complicated when the aphid arrives at NZ's at-risk populations of threatened endemic senecios.

https://inaturalist.nz/observations/322653324

#BiologicalInvasions #aphids #insects #nz #iNaturalistNZ

Sensible advice from Greater Wellington Council: don’t keep pests as pets.

https://www.rnz.co.nz/news/national/576465/greater-wellington-council-wants-people-to-stop-adopting-possums-as-pets

#nz #pests #pets #BiologicalInvasions

Watch out: the weather is warming and the American ragwort aphids are *multiplying*.

American ragwort aphids specialise on Senecio plants, of which NZ has many species, including some threatened endemic species.

The aphid arrived in NZ (somehow) in 2023, and has since got to work munching on our plants. The American aphids are also now being tended and protected by exotic Australian ants.

In the South Island these aphids are still restricted to Christchurch city (at least based on observations on #iNaturalist and #GBIF).

It would be great if you could keep a look out for them in other places. They're the only big black aphid in NZ (black bodies and legs).

Here are three of my observations of them from this month.

#aphids #PlantInsectInteractions #herbivory #BiologicalInvasions #NZ #Christchurch #iNaturalistNZ #insects #entomology

https://inaturalist.nz/taxa/453265-Aphis-lugentis

Zhikun Ren et al. predicted the current and future global #PotentialGeographicalDistribution of Bidens pilosa by integrating climatic, human-induced and biodiversity factors.

#BiologicalInvasions | #ClimateChange | #EnvironmentalFactors | #HabitatSuitability | #NicheOverlap

https://doi.org/10.1093/jpe/rtaf032

Les invasions biologiques marines by Goulletquer, Philippe, 2024

Biological invasions are one of the main causes of biodiversity decline worldwide.
Philippe Goulletquer reviews the latest advances in research into the detection, prevention, control and management of marine invasive species, in the light of the new regulations in effect.

#OpenAccess

https://directory.doabooks.org/handle/20.500.12854/153495

#books
#French
#BiologicalInvasions

❓Nutrient addition ➕ nematodes ➡️ competition between invasive and native plants

Results:
1️⃣ High-nutrient ➡️ invasions⬆️; local plants competition ➡️ invasions⬇️.
2️⃣ Low-nutrient ➕ nematodes ➡️ invasions⬆️; High-nutrient ➕ nematodes ➡️ invasions⬇️.

#BiologicalInvasions | #Exotic-nativeCompetition | #GlobalChange | #Nematode-plantInteractions | #ResourceAllocation

https://doi.org/10.1093/jpe/rtaf060