fieldherping.eu

Very cool pics. 145 specimens in one night is a great number. *g*

How many animals can you find e.g. 1 hour? Is it a healthy population, or are there limitations in available suitable habitat?

It may depend on the time of the year. In October 2009 I was out with a group that I took on a field trip into the habitat and we had a minimum number of 150 individuals (adults + subadults + juveniles) in two hours. During winter time there are usually less salamanders (about 40) when I cover a similar ground in about 1-2 hours. I have not counted the salamanders from my February trip yet, but I assume it were far less than 100.
There may be more indviduals out during spring migrations, but I never got around to count them because we are usually too busy with carrying toads and newts across the streets as it is not possible to use any fences for amphibians in the area.

Do you think there's drop in n° of active animals in summer?

And what about R. dalmatina- why in Poland its distribution is restricted to small area in SE of the country while it is present even in Sweden- much colder place?
Greetings

The more Salamandra I saw was 160 in 3 hours but It was Salamandra salamandra fastuosa. Fastuosa are very numerous in french Pyrénées.
Here is a little old abstract in french.

Michal Szkudlarek wrote:And what about R. dalmatina- why in Poland its distribution is restricted to small area in SE of the country while it is present even in Sweden- much colder place?
Greetings

No idea, could be many things. Different species require different conditions and can respond to different facets of weather and climate (sometimes winter minimum temp is the key, but for others rather the number of days above a certain temp in summer etc. etc.). Other than that, marginal populations are more susceptible to random extinction. Historical landscape change is also a factor. The list of possible explanations is long.

Pierre-Yves Vaucher wrote:The more Salamandra I saw was 160 in 3 hours but It was Salamandra salamandra fastuosa. Fastuosa are very numerous in french Pyrénées.
Here is a little old abstract in french.

Nice!

I'm trying to convince some fellow countrymen that that kind of high abundances are natural and more or less the norm in terrestrial salamanders, rather than the low densities established in some places with low habitat quality in Flanders.

Jeroen Speybroeck wrote:Do you think there's drop in n° of active animals in summer?

Depends on the weather. The region is very dry and I've not been out there after a nice thunderstorm, yet. I only spend time up there counting larvae in the ponds during summer, and am especially looking for albino larvae (or hunting abandoned Hymenochirus). I would assume that the number of salamanders in summer is similar to that in spring because you can recognize some of the individuals. It would be quite interesting to study how many of the juveniles stay in this habitat, migrate to the near gardens and forest and how many don't survive the winter. I think it would also be interesting how the population is affected by these dry periods during late spring and early summer. Due to the ponds being artifical we always have a high number of juveniles each autumn which contributes a lot to the large number of individuals that can be encountered from Sep-Nov.
I've only encountered a similar amount of more than 100 fire salamanders (mostly adults) in the forest of a small town nearby (app. 20 km) which was in early May 2009 or 2010. That was a quite warm night and it was raining heavily. You really had to watch your step. In contrast to the habitat that I visit on a regular basis with artifical basins, this forest has a really lovely little creek running through it.

@ Sandra:

Thanks a lot for your replies! I enjoy this kind of knowledge exchange very much, although I hope the berus lovers don't mind we discuss all these details on the forum

I don't do larval counts, because it's too much to handle already + it has been demonstrated that larval numbers are not really a good proxy for adult population size.

Me too, I have not really been out there immediately(!) after a summer thunderstorm, yet. I would assume that the effect of major activity on the 1st(!) rainy night after a dry period would be more different than that of the subsequent nights, in comparison with spring and autumn.

What's with the focus on albino larvae?

Is Hymenochirus an alien invasive in your area!?

> I would assume that the number of salamanders in summer is similar to that in spring
I don't know... In my area, two (not strict at all!) activity peaks are assumed (spring and autumn).

In my experience, the trouble with studying juveniles is that it is hard to find them in the first place (says literature, as well as my own observations), let alone find the same ones again... Getting an idea of winter survival sounds even harder & has never been done, as far as I know.

Last year was a terribly dry spring, causing most likely for a lot of the larvae to die. However, the impact on long-lived animals like this species, might be not that dramatic, imho.

Why do artificial ponds yield more juveniles? And how do you find juveniles (+ how do their numbers relate to adult numbers in %)?

> Due to the ponds being artifical we always have a high number of juveniles each autumn
> which contributes a lot to the large number of individuals that can be encountered from Sep-Nov.
You mean also juveniles by the latter number or post-metamorph animals in general?

So you don't agree that these high abundances are rather norm than exception in good natural habitat? I believe they are and that people underestimate abundance of terrestrial salamanders very often, due to their secretive habits.

> which was in early May 2009 or 2010
That would be rather late in my area, but maybe the big numbers are earlier near me (although that does not show from your posts)?