The unfortunately common narrative thread for a lot of insular diversity is a big bad continental species being introduced by people and wiping out the naïve insular endemics. But it appears that, just rarely, the opposite can occur.
I always assumed that the golden pothos, the famed ubiquitous houseplant, was native to tropical Africa or southeast Asia. I was also not surprised to find that it has become invasive in some parts of the world, especially Sri Lanka. Due to this, I was surprised to find out that pothos was, in fact, originally endemic to a single island: Mo’orea in French Polynesia. Mo’orea itself has faced a lot of invasion by introduced plants, so it was surprising to find out that an insular endemic plant from there could become invasive.
Does anyone know any similar examples? The only one that comes to mind is the New Zealand mud snail, which is endemic to freshwater habitats in New Zealand but has become invasive throughout western North America. Although that species presumably has a much wider range than pothos.
I don’t know any bad case compared to yours. Tasmania has some endemic eucaliptus, like Eucalyptus gunnii, which is planted around the world and has all the means to become invasive. Madagaskar has endemic aloes and Bismarckia nobilis which escapes cultivation, Panther chameleons also are said to live in Florida.
New Guinea Flatworms, endemic to New Guinea, have spread throughout the tropics. It’s more like the New Zealand mud snail in that its range isn’t tiny, but its introduced range is significantly larger than its native range for sure.
Kalanchoe delagoensis of Madagascar (Mother-of-Thousands),with its vegetative plantlets, has taken off across the globe.
Trichosurus vulpecula (possum) was endemic to Australia until some bright spark brought it over to New Zealand for the fur trade in the 1850s. Next minute, it’s a major NZ pest species. Ironically it’s a protected species in its homeland.
The European rabbit (Oryctolagus cuniculus) is a huge pest in Australia. But any observations of it are helpfully labelled as “EN” - conservations status - endangered. Ha!
Oh yeah, completely forgot Platydemus! That’s another particularly insidious example, though most of its most devastating impacts have happened primarily on other islands; I’m not sure if mainland areas that it has been introduced to have seen as dramatic land snail declines. Sure as hell hope they haven’t.
This definitely happens a lot more with animals than plants. Even most of the restricted range/insular endemic plants that become invasive don’t have as small a native range as pothos (Mo’orea has a smaller area than Washington DC), surprisingly enough.
That is a huge area, maybe not the biggest for the mammal, but that’s the same for European ungulates, ancestors of sheep and goat also have pretty narrow areas, but not islands.
Echium candicans, Echium pininana, Aeonium arboreum, Aeonium haworthii, Aichryson laxum from the Canary Islands are invasive in some parts of the world.
Epilobium brunnescens, Acaena novae-zelandiae and Crassula helmsii are examples from New Zealand that have become invasive in some areas.
It’s an island, huge peninsula is not, or should we mention any endemic of any area? There’re interesting mountain endemics, we either stick to islands or talk about everything. OP specifically said island biodiversity suffers from invasives a lot, not at the same level as part of the continent does.
Why not, “endemic to a biogeographically isolated area”? That fits the definition of “insular”. That would qualify for islands, peninsulas, even some mountain ranges, while excluding things like entire continents or most countries.
I think I will include restricted-range mainland species for this definition as well if their ranges are restricted enough, though species that are specifically isolated to islands are especially interesting as they’re more likely to become naïve to invasive species.
Though correct me if I’m wrong on this, but I do think the semi-restricted range of the European rabbit (which still isn’t really all that small compared to some other examples) is more a consequence of previous glaciations than anything else? I’m not sure on that though.