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Marsh frog research

Printed From: Reptiles and Amphibians of the UK
Category: Alien & Naturalised species of the UK
Forum Name: Naturalised
Forum Description: Concerning non-indigenous species that are no threat to native fauna
Printed Date: 17 Apr 2021 at 11:34am
Software Version: Web Wiz Forums 11.06 -

Topic: Marsh frog research
Posted By: marshfrogsearch
Subject: Marsh frog research
Date Posted: 16 Apr 2013 at 8:50pm
I have recently started a PhD studentship at the University of Kent doing research to determine whether marsh frogs are having an impact on the distribution of common frogs in South East England. I need to get a better idea of the distribution of marsh frogs so I would be very grateful if people could log their marsh frog sightings on my website" rel="nofollow -

or the Kent Reptile and Amphibian Group website" rel="nofollow - .



Posted By: herpetologic2
Date Posted: 18 Apr 2013 at 10:40am
Hi Aidan,
Looks like an interesting piece of research. I am heading up the Record Pool database. Would it be useful for us to work together on this.
I am curious whether there is any evidence of any impact of these frogs on our native frogs. There is a student at Writtle College who is looking at European Water frogs at Rainham Marshes in Essex looking at their impacts (positive and negative) on that reserve. The frogs there were introduced or rather they first appeared in 2004.
Another population in South Essex has a history dating back to its original introduction in around the 1990's and occupies deep ditches borrow dykes and fishing lakes.
Another research project looked at the prey items of water frogs at the London Barns Wetland Centre do you have a copy of that research at all?
These frogs are still being spread across the country by Fisherman (recent introduction reported from Kent to fishing lakes in Essex), pet stores (plenty for sale acorss the home counties), members of the public (spawn & tadpoles) and deliberate introductions by keepers (anecdotally).
We had new records from fishing lakes in Leicestershire originally reported as 'Bullfrogs' but followed up and were European Water Frogs from photos taken at the site.
I think that there is a real issue with these frogs moving closer to the Pool frog reintroduction site in Norfolk it would possibly be a disaster if any of these were introduced and the pool frog hybridises with the southern European water frogs.
Do you have evidence that the 'Marsh' type frogs have impacts on our native grass or brown frog? 

Report your sightings to the Record Pool" rel="nofollow -

Posted By: marshfrogsearch
Date Posted: 18 Apr 2013 at 7:18pm
Hello Herpetologic2,

Yes it would be useful to work together. As in my previous post I am trying to get as much information on the distribution of marsh frogs and I would be happy to share data. My email address is" rel="nofollow - .

The research on the impact of water frogs in Rainham Marshes sound interesting. I would like to know more about this research particularly how the impacts are being measured. Do you have the contact details of the student at Writtle College?

University College London are sending me a copy of the Masters dissertation ‘The Diet of the Marsh Frog [Rana ridibunda] at the London Wetland Centre'.

The evidence comes from work done by Lee Brady using Kent Reptile and Amphibian Group (KRAG) data. Lee has written about this in his blog these two links take you to the relevant pages." rel="nofollow -
and" rel="nofollow -

A very truncated version of the blog entries is the data shows that common frogs are less likely to be found in high pond density areas. One explanation for this is that marsh frogs are preventing common frogs from using ponds occupied by fish to avoid predation by great crested newts. But it is worth reading the bog to follow the logic. As the blog suggests some of the analysis is based on a very limited amount of data. But I thought it was worth doing more research to see if the question about the impact of marsh frogs on common frogs could be answered.


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