In the past two decades, water frogs have spread rapidly in Central Europe. Using a new statistical model, researchers from the University of Basel were now able to show that local species such as the Yellow-bellied Toad and the Common Midwife Toad are suffering from the more dominant water frogs. The journal American Naturalist has published their results.
The composition of species communities can change considerably over time, often due to human influences. Even though these changes have led to the decline of many species, some have also been able to benefit. Such so-called invasive species then may either hunt other species or replace them in their natural habitat.
Some of the most invasive amphibians belong to the water frog species complex. The Eurasian Marsh Frog, native to Eastern Europe, has become particularly dominant in Switzerland in past years. Humans are to blame for this development, as they began to import the frog species to Central Europe for consumption beginning of the 1960s.
The Basel zoologists Tobias Roth, Christoph Bühler and Valentin Amrhein have now used the data of over 1000 bodies of water in the Swiss Canton Aargau in order to study the impact of water frogs on native amphibians using a new statistical model. The cantonal Amphibian Monitoring Aargau supplied the necessary observational data.
However, such data is often difficult to interpret: If, for example, there are only few observations of a species, does that mean that the species is actually rare or is it only observed rarely? The statistical model used by the Swiss researchers takes into account the different detection probabilities of species as well as other environmental factors.
Native toads in decline
The results show that Yellow-bellied Toads and Common Midwife Toads have smaller communities whenever water frogs are also present at the same body of water. “Based on our analysis we estimate that the populations of both species would be up to five times bigger without the water frogs' presence,” says Christoph Bühler, Head of Amphibian Monitoring Aargau.
In case of such a competitive situation, caused by human influences, conservationists have to decide whether they should intervene with regulatory measures. Because the influence of the invasive Marsh Frog on the native species is great, some measures against the dominant frog could be indicated in order to protect the populations of local species.
Evaluating the situation is however further complicated due to the fact that it is not only the Eurasian Marsh Frog heating up the competition for habitat. Crossings between the Marsh Frog and native amphibians have led to closely related water frog hybrids that are also acting invasive and that cannot, due to mixed genetic material, be clearly identified as alien.
“What is clear, however, is that the changes in the landscape currently favor water frogs,” says Valentin Amrhein from the Department of Environmental Sciences at the University of Basel. “Small waters that dry out quickly and are being avoided by water frogs but sought after from other species have become rare these days. The spread of invasive species is often supported, consciously or unconsciously, by the actions of humans and cannot easily be undone.”
Tobias Roth, Christoph Bühler und Valentin Amrhein
Estimating effects of species interactions on populations of endangered species
American Naturalist (2016) | doi:10.1086/685095
PD Dr. Valentin Amrhein, University of Basel, Department of Environmental Sciences, Zoology, phone +41 (0)79 848 99 33, email: email@example.com
Olivia Poisson | Universität Basel
Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses