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
Global threat to primates concerns us all
19.01.2017 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung
Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
19.01.2017 | Earth Sciences
19.01.2017 | Life Sciences
19.01.2017 | Physics and Astronomy