Natrix tessellata & Vipera aspis by Leman Lake, Switzerland

[Bastien Comment]

16.05.2011

This a place where I come for more than 10 years near Lausanne by the Leman Lake with plenty of Natrix tessellata. I've known times when I could see more than 20 snakes in an afternoon but the last times I had come had not been very successful. Though it might also simply have to do with the temperature (the last times, it was at least 6 degrees hotter than this time, about 20 degrees), I've been very happy to see that this population is doing pretty well at least in the first place I visited. In the second, I haven't found any Natrix but...I've found an asp viper! This is really very surprising to me because I've come here in Spring, Summer and Autumn, mornings, noons and afternoons (and even begining of the evening when there's still some sun) and I had never ever found a viper there, so close to the water.

[Mario Schweiger]

Good pictures of many individuals of this invasiv species

Mario

[Wolfgang Wüster]

16.05.2011

This a place where I come for more than 10 years near Lausanne by the Leman Lake with plenty of Natrix tessellata. I've known times when I could see more than 20 snakes in an afternoon but the last times I had come had not been very successful. Though it might also simply have to do with the temperature (the last times, it was at least 6 degrees hotter than this time, about 20 degrees), I've been very happy to see that this population is doing pretty well at least in the first place I visited. In the second, I haven't found any Natrix but...I've found an asp viper! This is really very surprising to me because I've come here in Spring, Summer and Autumn, mornings, noons and afternoons (and even begining of the evening when there's still some sun) and I had never ever found a viper there, so close to the water.

Part of the reason you may not be seeing quite as many is that there is an eradication campaign against Natrix tessellata in progress in Lake Geneva. The species you SHOULD be finding there in numbers is Natrix maura, not Natrix tessellata, and it appears likely that the reason for the decline of the native species is in fact the invasive dice snake. While it is always painful to think of killing snakes, the fact is that the dice snakes should not be in Lake Geneva, and moreover, this would give them a potential starting point to invade other river systems where they might endanger N. maura. Whoever had the bright idea of releasing dice snakes into Lake Geneva deserves to have their backside kicked long and hard!

The lakeside vipers are a really cool find!

[Mario Schweiger]

On our way home from Berner Oberland I showed my compagnions the place where the introduced Natrix tessellata are living at lake Alpnach.
See also posting from last year:
http://www.fieldherping.eu/Forum/viewtopic.php?f=10&t=451

Close to the parking site we met a group of nature interested people, guided by one guy of the KARCH.
At the parking place he had all the introduced snake species living now at lake Alpnach, like Vipera aspis ssp., Vipera ammodytes, Zamenis longissimus and a Natrix n. helvetica/persa hybrid.

Lake Alpnach and its surroundings, Europe´s largest outdoor pan

Mario

[Bastien Comment]

@Wolfgang: Of course I know that the tessellata is not native from here and was imported but I didn't know that there was an eradication campaign against it...I think I've never seen a Natrix maura here indeed. Shouldn't I find also Natrix natrix in the area? Again in over 10 years, I've never seen one here...

[Wolfgang Wüster]

Close to the parking site we met a group of nature interested people, guided by one guy of the KARCH.
At the parking place he had all the introduced snake species living now at lake Alpnach, like Vipera aspis ssp., Vipera ammodytes, Zamenis longissimus and a Natrix n. helvetica/persa hybrid.

There are wild ammmodytes living around Lake Alpnach?!?!?

[Mario Schweiger]

Close to the parking site we met a group of nature interested people, guided by one guy of the KARCH.
At the parking place he had all the introduced snake species living now at lake Alpnach, like Vipera aspis ssp., Vipera ammodytes, Zamenis longissimus and a Natrix n. helvetica/persa hybrid.

There are wild ammmodytes living around Lake Alpnach?!?!?

Yes, still there must be at least one male living!
Last year, when KARCH was doing measurements on V. aspis from lake Alpnach, they had a high gravid female, giving birth to hybrids in the box (stress?).
A friend saw last year a viper crawling into rocks very fast - so no picture. But from markings, he was sure it was an ammodytes.

Mario

[Wolfgang Wüster]

Yes, still there must be at least one male living!
Last year, when KARCH was doing measurements on V. aspis from lake Alpnach, they had a high gravid female, giving birth to hybrids in the box (stress?).
A friend saw last year a viper crawling into rocks very fast - so no picture. But from markings, he was sure it was an ammodytes.

I think I will book a flight to Zürich right now....

Bastien: on e of the reasons Natrix maura is rare is the presence of N. tessellata - you rarely the get two in the same habitat. Natrix natrix is not really a snake of open lake shores like in your picture, so I am not so surprised that it would not be found there. However... do you have a higher resolution version of the photo just above the shot of the railway line on the Lake shore? The pattern on that looks rather maura-like...

[Mario Schweiger]

I see a maura on this pic too

[Jeroen Speybroeck]

Héhé, I was thinking the same thing, and then I read the last 2 posts...
This is a maura by my book!