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Re: some herps from Polish/Czech borders

PostPosted: Fri Sep 16, 2016 10:21 am
by Michal Kukla
Found this Trachemys scripta elegans female nerby Wroclaw, Poland. She has ~25cm carpax!

Image
bigger: https://c1.staticflickr.com/9/8488/2900 ... 49c1_o.jpg

Re: some herps from Polish/Czech borders

PostPosted: Fri Sep 16, 2016 10:29 am
by Jeroen Speybroeck
Cool monster!

Re: some herps from Polish/Czech borders

PostPosted: Fri Sep 16, 2016 11:12 am
by Mario Schweiger
nice picture!

Re: some herps from Polish/Czech borders

PostPosted: Fri Sep 16, 2016 12:58 pm
by Ilian Velikov
Great shot and a beautiful turtle! Did you find her in a natural or artificial water body?

Speaking of which - Is there any actual research and publications on the effects of Trachemy on European turtle species? Obviously they compete with the local species for food, basking sites, etc. but is there any evidence that their presence actually decreases populations of local turtles? Most places I've found Emys at have plenty of resources and high concentration of individuals. So their numbers are most likely regulated by predation and death by natural causes rather than competition among individuals. Also it's quite common for a few species of turtle to live peacefully together. So I wonder if adding a few Trachemys to the local turtle population is actually that dangerous.

Re: some herps from Polish/Czech borders

PostPosted: Fri Sep 16, 2016 1:20 pm
by Jeroen Speybroeck
Ilian Velikov wrote:Great shot and a beautiful turtle! Did you find her in a natural or artificial water body?

Speaking of which - Is there any actual research and publications on the effects of Trachemy on European turtle species? Obviously they compete with the local species for food, basking sites, etc. but is there any evidence that their presence actually decreases populations of local turtles? Most places I've found Emys at have plenty of resources and high concentration of individuals. So their numbers are most likely regulated by predation and death by natural causes rather than competition among individuals. Also it's quite common for a few species of turtle to live peacefully together. So I wonder if adding a few Trachemys to the local turtle population is actually that dangerous.

There's quite a bit of literature, check out Mario's DB as a starting point. A striking example is a specific spot on Menorca. Bobby went there the first tim, with Emys being extremely abundant and readily visible. Second visit, we didn't find any Emys yet plenty of red-ears. Same in Aiguamolls, with Mauremys first being everywhere and on a second visit hidding in suboptimal parts of the habitat (shaded spots etc.). These are of course just anecdotes, without any idea of other things that might have happened, but still, they are stuck in my mind...

Re: some herps from Polish/Czech borders

PostPosted: Fri Sep 16, 2016 2:31 pm
by Berislav Horvatic
Obviously they compete with the local species for food, basking sites, etc. but is there any evidence
that their presence actually decreases populations of local turtles?

I visited Mario's favourite "emys pond" on the island of Krk this August. Sorry to say, but not a single
Emys spotted, while the pond was literally swarming with Trachemys. A few years ago it wasn't like
that, but now it is. Bye-bye Emys, bye-bye the "emys pond".

Re: some herps from Polish/Czech borders

PostPosted: Fri Sep 16, 2016 3:21 pm
by Ilian Velikov
Berislav Horvatic wrote:Sorry to say, but not a single
Emys spotted, while the pond was literally swarming with Trachemys.


Any ideas as to why this happened? Do you really think it's just competition for food? And did Emys died off or dispersed to other less crowded habitats? In their natural range Trachemys coexist with other turtle species that occupy the same ecological niche, so why not in Europe? Trachemys are supposedly "more aggressive" but I don't understand what's that suppose to mean as I've seen plenty of photos of Trachemys with other species literally basking on top of each other. So where's the competition for basking spots and food?

Re: some herps from Polish/Czech borders

PostPosted: Fri Sep 16, 2016 3:40 pm
by Jeroen Speybroeck
PDF numbers
1556
1557
1919
3412
7858
7859
7860
8765
9972

Re: some herps from Polish/Czech borders

PostPosted: Fri Sep 16, 2016 4:04 pm
by Ilian Velikov
Thanks Jeroen! I forgot that we have that amazing database :)

After a quick glance through these it is obvious that the presence of Trachemys has negative effects on local turtles but I'm surprised that it happens so quickly - just "a few years" as Berislav pointed out.

Re: some herps from Polish/Czech borders

PostPosted: Fri Sep 16, 2016 6:52 pm
by Michal Szkudlarek
from what i remember alien species of turtles do not reproduce in poland, only autochtonic Emys does