This week I found what I think is the first wild seedling of a tulip tree I've seen in NZ. It's the first record of a wild tulip tree from the greater Christchurch area, and one of few from NZ, on #iNaturalist.

Why does this matter? Because this is how most tree weeds start. Ingo Kowarik's classic 1995 study from Branderburg, Germany, showed that "on average, there was a time lag of 147 years between the introduction to Brandenburg and the initiation of invasion (170 years for trees, 131 for shrubs)" and that the most successful invaders were not neccesarily the earliest to go wild.

My tulip tree seedling is the first offspring of two tulip trees planted on Lincoln University's campus about 60 years ago. The species had been rarely planted in the city until recently. It was fashionable at the time the city was rebuilt after the earthquakes, so now we've got lots of them planted. We may see many more wild tulip tree seedlings in another half century.

Time will tell how well suited it is to NZ's environments.

https://www.inaturalist.nz/observations/365601855

https://www.researchgate.net/profile/Ingo-Kowarik/publication/230693763_Time_lags_in_biological_invasions_with_regard_to_the_success_and_failure_of_alien_species/links/0912f50dc8d572fd12000000/Time-lags-in-biological-invasions-with-regard-to-the-success-and-failure-of-alien-species.pdf

#botany #weeds #BiologicalInvasions #WoodyWeeds #nz #Liriodendron

#NewPaper out: Twenty-five years of Neobiota: building a community for invasion science in Europe and beyond by Ingo Kowarik and many great colleagues @TheresaHenke

#alienspecies #biologicalinvasions #neobiota

https://neobiota.pensoft.net/article/173229/

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