Mediterranean Geckos are an introduced species in Missouri. This is not an obscure fact. It’s mentioned on the species’ Wikipedia page, it’s covered in this field guide to the lizards of Missouri (which is published by the Missouri government), and the species clearly isn’t too uncommon a sight in the state given the species’ 49 (and counting) iNat observations in the state.
But, there’s a bit of a complication here. Mediterranean Geckos cannot survive the climate in Missouri. According the Missouri Department of Conservation: “this nonnative species is unlikely to survive in the outdoor conditions of Missouri and is found only in warm urban buildings, especially greenhouses, zoo and university buildings, and homes”.
According to the iNat page announcing the “Not Established” annotation, populations which are confined indoors qualify as “Not Established”. But does this count? While geckos in Missouri are confined indoors during the winter months, they can and do move from building to building during warmer times of year, and have clearly established themselves in the state (over a pretty wide area, too). Yet, for part of the year, they certainly are confined indoors.
So, what is the status of Missouri’s Mediterranean Geckos on iNat? Should they be marked as “Not Established” or not? Missouri is also far from the only place you run into this exact problem with this exact same species. Plenty of other US states have populations Mediterranean Geckos too including some some states much colder than Missouri (Wisconsin! ).
This also becomes very relevant to other animal groups if the “Not Established” annotation ever becomes usable outside of herps, including House Mice, many pest cockroach species, ants, ect.
[Feel free to use this as a discussion space for if all-indoor populations should even be included in the “Not Established” annotation, since this made me wonder that myself].
That they rely on human structures to a large extent is not surprising as they are often called house geckos. But does their reliance on human-generated heat sources mean they are not established? I’d be curious to know in these colder areas to what extent this species brumates, if at all, or does it have to have above-freezing temperatures at minimum year-round to survive. Also, to what extent they use the exterior of a building in cold weather but gravitate to refugia on the building where some heat is available to keep from freezing.
I don’t think their reliance on human-generated heat sources during winter in some locations would require that they be classified as non-established. But I can see an argument that they are not fully adapted to those locations, absent human assistance.
Keep in mind this is about the “Not Established” annotation, which is kind of unrelated to whether a population of a species is established. They are for sure established. The question is, should they be marked with the “Not Established” annotation.
(And, frankly, whether indoor populations should be included under the “Not Established” annotation at all).
If an observed gecko is part of a known established population, and hatched out at that location, and it’s not a waif (a single individual that was transported from elsewhere) then it’s established, whether it’s inside a house or not. I suppose you could argue that if all members of a population are contained within, say, a greenhouse and could not survive outside of that structure, you could even call them captive. But that’s another topic.
I think they could be considered established. Not established is meant to refer to when individuals have escaped, but have no chance of surviving or breeding, like that alligator in a stock pond in California. It could live there for decades for all we know, but isn’t going to be able to reproduce. The geckos are just living in human created environments but aren’t pets. If they aren’t established, neither are the cellar spiders who live in everyone’s basement in Vermont. For that matter nearly all animals and plants live in environments influenced by humans. So i think not established should be saved for escapees, dumped pets, and waifs.
Regarding the brumation and winter activity of Mediterranean House Geckos, this study done in the US indicates that they are active in a wider range of temperatures in the US than they experience in their native range and may not be 100% reliant on anthropogenic heat sources even in winter months.
Personally, regardless of whether they’re depended on anthropogenic heat sources I would classify them as ‘established’ as those anthropogenic sources are part of the landscape now.
They are for sure established, in my opinion at least. But the listed definition for the “Not Established” annotation explicitly specifies that populations confined indoors count as “Not Established” for iNat purposes (see the “What Does Establishment Mean” section). I am of the opinion that this doesn’t make much sense and shouldn’t be the case, since it creates bizarre scenarios like this, but it is part of policy.
Given that you are part of iNat’s staff, does this indicate a change in this policy?
I think they are established. The exact wording on the annotation has some wiggle room, as many geckos are likely not surviving “inside” per se - ie, they aren’t in the interior living space of the building. They are under shingles/shutters, in roof eaves, ventilation systems, etc. The liminal spaces of buildings that are not exactly exterior and receive some heat supplement from the building. I don’t think this qualifies as “indoors” myself, so I see no issue.
For instance, I would think that many common pests like rats and cockroaches (many of which live out their entire lives in interior spaces of buildings, but also do move outside and between buildings) are definitely established.
However, @raymie I also don’t think that you accurately represented the “official” iNat definition of the annotation when you said
and
The documentation which you linked does not include “indoors” or “inside” at all - it does specifically list greenhouses as counting as not established. But based on my reading of the iNat documentation, it’s clear that the geckos are established, and I think this thread could be solved.
I agree. “Confined” indoors means something prevents their leaving a building.
I read this as not ever being able to leave the building of their own will.
Quite a number of creatures spend winter – in all or part of their range – unable to move at all. For example, some butterflies overwinter as eggs. Those eggs are rarely found inside buildings. But the example shows that seasonal immobility by no means prevents a species from extending its range and becoming established.
If these types of observations are not supposed to be marked as “Not Established”, then I’ve seen many mismarked observations of house geckos as “Not Established” when they actually are established. Given there is no way to remove annotations, what should be done about this?
).