Navigation Links
Indigenous water frogs under threat
Date:11/29/2007

Angers/Leipzig. Indigenous water frogs can be crowded out by immigrant or imported species. This is the finding of a Franco-German study. The scientists investigated water frog populations in France and Northern Spain and noticed that the marsh frog (Rana ridibunda), which normally occurs only in Eastern Europe, has the potential to crowd out indigenous species like Grafs hybrid frog (Rana grafi) and the Iberian water frog (Rana perezi). The scientists believe this ability is related to the fact that the marsh frog lives longer and grows faster than the indigenous species. In addition, the female marsh frogs produce more progeny than their competitors, the researchers write in the scientific journal Comptes Rendus Biologies. The marsh frog has now spread from Central Asia as far as France and Spain. This latest spread is attributed to imports of live animals for culinary purposes. As the foreign species mix with the indigenous species, the indigenous water frogs are being pushed back into just a few areas. Imports of invasive species by humans are regarded as one of the main threats to species diversity on earth, alongside climate change.

Most stable marsh frog populations in France and Switzerland originated from frogs bred for gourmet restaurants or imported directly from various source countries. The frog fauna along larger river flood plains in both countries has now altered significantly in favour of the new frog species. Until now though, it was not clear why the new species had been able to establish themselves in the face of the indigenous species. The team of scientists investigated over 700 water frogs from 22 locations in the Rhone drainage basin in France and four locations in the Ebro drainage basin in Spain. "We noticed that the introduced marsh frog has a high competitive potential, particularly in high-oxygen, low-salinity freshwater. In these conditions the indigenous frogs hardly stand a chance," declares Dr Dirk Schmeller of the Helmholtz Centre for Environmental Research (UFZ). The displacement process is linked to the fact that the marsh frog grows faster than the indigenous frogs, and is in direct competition for food. In addition, female marsh frogs live longer and are more fertile. This means that over the course of their lives they produce significantly more progeny, thereby crowding out the other frog species. The number of progeny is increased still further because when the marsh frog mates with Grafs hybrid frog (Rana grafi) or the edible frog (Rana esculenta), it produces marsh frog progeny. This may sound astounding, but can be attributed to a special type of reproduction called hybridogenesis, which is a special feature of water frog reproduction. All these factors may lead to the extinction of the indigenous water frog species, the researchers believe, and therefore recommend that the spread of the marsh frog be closely monitored.


'/>"/>

Contact: Tilo Arnhold
presse@ufz.de
49-341-235-1269
Helmholtz Association of German Research Centres  
Source:Eurekalert

Related biology news :

1. Freshwater supplies threatened in central Pacific
2. University of Oregon researcher finds that on waters surface, nitric acid is not so tough
3. Innovative civil engineering application promises cleaner waters
4. Safe water: simpler method for analyzing radium in water samples cuts testing time
5. Researchers find new taste in fruit flies: carbonated water
6. Low oxygen in coastal waters impairs fish reproduction
7. Extra gene copies were enough to make early humans mouths water
8. Acid rain has a disproportionate impact on coastal waters
9. HARDY rice: less water, more food
10. New microsensor measures volatile organic compounds in water and air on-site
11. Alternative methods proposed to detect pesticides and antibiotics in water and natural food
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Indigenous water frogs under threat
(Date:5/24/2016)... May 24, 2016 Ampronix facilitates superior patient care by providing unparalleled technology ... LCD display is the latest premium product recently added to the range of products ... ... ... 3d Imaging- LCD Medical Display- Ampronix News ...
(Date:5/16/2016)... 2016   EyeLock LLC , a market leader ... of an IoT Center of Excellence in ... development of embedded iris biometric applications. EyeLock,s ... and security with unmatched biometric accuracy, making it the ... DNA. EyeLock,s platform uses video technology to deliver a ...
(Date:5/9/2016)... UAE, May 9, 2016 Elevay ... comes to expanding freedom for high net worth professionals ... in today,s globally connected world, there is still no ... could ever duplicate sealing your deal with a firm ... passports by taking advantage of citizenship via investment programs ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... discussions on a range of subjects including policies, debt and ... Poloz. Speaking at a lecture to the Canadian ... to the country,s inflation target, which is set by both ... "In certain areas there needs to be ... why not sit down and address strategy together?" ...
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... ... is pleased to announce the launch of their brand, UP4™ Probiotics, into Target ... over 35 years, is proud to add Target to its list of well-respected ...
(Date:6/23/2016)... ... 23, 2016 , ... Charm Sciences, Inc. is pleased to ... AOAC Research Institute approval 061601. , “This is another AOAC-RI approval of the ... Vice President of Regulatory and Industrial Affairs. “The Peel Plate methods perform comparably ...
(Date:6/23/2016)... ... June 23, 2016 , ... STACS DNA Inc., the sample tracking software company, ... Crime Laboratory, has joined STACS DNA as a Field Application Specialist. , “I ... President and COO of STACS DNA. “In further expanding our capacity as a scientific ...
Breaking Biology Technology: