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I am an Associate Professor at the Biogeography Department of Trier University,
Germany, and the PI of several research projects related to
   - species genesis and delimitation, as well as species' geographic range genesis,
   - character evolution, in particular traits related to aposematism,
   -
ecological niche exploitation and change,
   - biological response to past and future landscape or climate change as well as
      to human impact including pesticide applications,
   - the impact of invasive species and pathogens
 

Focal study regions are rainforests of South America and Africa but also our 'back garden' in central Europe. Our key organisms are amphibians. Among our main study groups are poison frogs (Dendrobatidae), harlequin toads (Atelopus), reed frogs (Hyperoliidae) and European land salamanders (Salamandra). But these are not exclusive, as we also investigate reptiles, invertebrates or others. We study species and their environments at different spatial, temporal and taxonomic scales.

In an interdisciplinary frame, our lab may best be seen at the interface of systematics, ecology, biogeography, evolution and conservation. Methodically, we make use of modelling, GIS applications, (molecular) phylogeny etc. and process lab, experimental and field data. We very much like collaborative work!

Lötters is an editor of PLoS ONE and Salamandra. He is member of the IUCN Species Survival Commission, the 'Biodiversity, GMO-Monitoring and risk management' committee of VDI, and he is co-speaker of the 'Arbeitskreis Biogeographie'. He was an editor of Biotropica, a member of the International Committee of the World Congress of Herpetology and the vice-president of the German Herpetological Society DGHT .

Lab News and Research Highlights

Dangerous Salamander Fungus Spreads...

01/11/2016

For some years now, we have to struggle with a new amphibian pathogen in Europe, the skin-eating salamander fungus, Batrachochytrium salamandrivorans (Bsal). It kills salamanders and newts. Especially the Fire salamander is affected, while frogs and toads seem fine with Bsal. Apparently of Asian origin, there is evidence that Bsal is now emerging in its invasive European range, although this is not proven with certainty yet. Bsal is considered a serious threat to Western Palearctic amphibian diversity. 

Our ongoing research — in collaboration with Biostation Aachen, Biostation Düren, Braunschweig University, Ghent University, RAVON, and others — has yielded 14 of 55 studied sites as Bsal-positive in Belgium, Germany and the Netherlands. In some of these, Bsal was not detected on earlier occasions. Read more in our scientific publication by Spitzen van-der-Sluijs et al. (2016), or see a public TV report on SWR. For updates and most recent Bsal findings, we recommend the webpage of RAVON.

Because of the threat by Bsal and to aid mitigation strategies and conservation action, we for the first time have modelled the potential distribution of this fungus for the region where it is so far recorded in Europe. In this study, we created various models with different data and assumptions. As a novelty, we also incorporated fine-scale weather data, which allowed us to emphasize predictors in accordance with the known pathogen's biology. In this way, we were able to appreciate Bsal's invasion potential in geographic space and to identify areas which are of high invasion risk, such as the Black Forest.

Spitzen-van der Sluijs, A., A. Martel, J. Asselberghs, E.K. Bales, W. Beukema, M.C. Bletz, L. Dalbeck, E. Goverse, A. Kerres, T. Kinet, K. Kirst, A. Laudelout, L.F. Marin da Fonte, A. Nöllert, D. Ohlhoff, J. Sabino-Pinto, B.R. Schmidt, J. Speybroeck, F. Spikmans, S. Steinfartz, M. Veith, M. Vences, N. Wagner, F. Pasmans & S. Lötters (2016): Expanding distribution of lethal amphibian fungus Batrachochytrium salamandrivorans in Europe. — Emerging Infectious Diseases, 22: 1286-1288.

 

Feldmeier, S., L. Schefczyk, N. Wagner, G. Heinemann, M. Veith & S. Lötters (2016): Present and future high risk zones for the spreading lethal salamander chytrid fungus in its invasive range in Europe using bioclimate and weather extremes. PLoS ONE, 11: e0165682.



Diversification and Niche Conservatism in an African Frog Since the Miocene

23/10/2016

The Mascarene ridged frog (Ptychadena mascareniensis species complex) is known from many humid savannas and open forests of mainland Africa, Madagascar, the Seychelles and the Mascarene Islands. In a recent study (Zimkus et al. 2017; online first now), by multiple collaborators, we demonstrate high levels of genetic differentiation with ten distinct lineages, and that Central Africa is diversity hotspot for these frogs. Further, we show that most speciation took place throughout the Miocene, including 'Out-of-Africa' overseas dispersal. Interestingly, the bioclimatic niche was remarkably well conserved, with most species tolerating similar temperature and rainfall conditions common to the Central African region. The P. mascareniensis complex provides insights into how bioclimatic niche shaped
the current biogeographic patterns with niche conservatism being exhibited by the Central African radiation
and niche divergence shaping populations in West Africa and Madagascar.

Zimkus, B.M., L.P. Lawson, M.F. Barej, C.D. Barratt, A. Channing, K.M. Dash, J.M. Dehling, L. Du Preez, P.-S. Gehring, E. Greenbaum, V. Gvoždík, J. Harvey, J. Kielgast, C. Kusamba, Z.T. Nagy, M. Pabijan, J. Penner, M.-O. Rödel, M. Vences & S. Lötters (2017): Leapfrogging into new territory: How Mascarene ridged frogs diversified across Africa and Madagascar to maintain their ecological niche. — Molecular Phylogenetics and Evolution, 106: 254-269.



The DZG "Masterpreis" 2016 Goes to Our Lab

15/09/2016

The German Zoological Society DZG (Deutsche Zoologische Gesellschaft) has awarded Sarah S. Bisanz for her MEd thesis in Biology entitled "Aktivitätsräume von Ameerega trivittata im amazonischen Tieflandregenwald in Peru". In her study, Sarah examined the home range behavior of a Neotropical poison frog at Panguana Biological Fieldstation in a lowland rainforest of Amazonian Peru.

Fieldwork was carried out in 2014. We have repeated her study in the following year. A scientific publication is in preparation and will shortly be published reporting site fidelity over consecutive years and female home range behavior, so far only known in male A. trivittata.

The Meaning of Colors

30/08/2016

One of our key research topics is the evolution and the function of warning colors (aposematism) in toxic prey. We study Neotropical harlequin frogs, Atelopus spumarius and related forms from the Amazon basin and adjacent areas.

Interesting in these frogs is:
(1) They are all toxic and possess the highly potent tetrodotoxin (TTX), a substance known from many animals including puffer fish (for more information on TTX see our recent Quick Guide in Current Biology). The degree of intra- and interspecific variation is subject to ongoing research.

(2) These harlequin frogs highly vary in dorsal color conspicuousness: some are vividly colored while others are virtually non-aposematic.

(3) Some have colorful ventral sides and some even hand/foot soles. These are red and we consider them to represent flash marks to warn potential predators. Actually, we have been able to show that red hand/foot soles can almost only be seen by birds. In contrast, dorsal colors are seen by a variety of potential predators including crabs. See an interesting video on a crab predation attempt here; the frog in the end is apparently too toxic for the crab.

Recent fieldwork by Daniela C. Rößler and Max N. Lorentz has been very successful and they are currently analyzing relationships between color conspicuousness and toxicty aspects.

Lorentz, M.N., A.N. Stokes, D.C. Rössler & S. Lötters (2016): Tetrodotoxin in animals. — Current Biology, 26: R870-R872.

 

New Poison Frog Book Out Now

16/05/2016

This new volume with more 500 pages and more than 200 color illustrations (about half of which are detailed scientific drawings) is published in the Conservation International field guide series. It treats all aposematic, i.e. colorful and toxic, species in the poison frog family Dendrobatidae which occur in the Andean countries of South America.

This piece of work is the result of a collaborative work by many contributors. It contains information on species' adult and larval morphology, alkaloid profiles, natural history, calls, reproduction, distribution and threats.

The book can be obtained from Chimaira.

Kahn, T.R., E. La Marca, S. Lötters, J.L. Brown, E. Twomey & A. Amézquita (2016): Aposemtaic poison frogs (Anura; Dendrobatidae) of the Andean countries Bolivia, Colombia, Ecuador, Peru and Venezuela. — Conservation International, Washington D.C. (USA), 582 pp.

Macroecology Meets Biogeography

17/03/2016

We have recently hosted the first joint conference of the "Arbeitskreis Biogeographie" (VGDH) and the "Arbeitskreis Makroökologie" (GfÖ) (15-17 March 2016). Both macroecology and biogeography, besides their own nature, show a large overlap in topics, concepts and methods. The goal of the scientific meeting was to learn more about the other discipline’s scopes and to identify synergies. We had more than 50 participants from seven countries who found the meeting was a successful cometogether. The program included 26 talks and 5 posters. For more information, abstracts etc. see here. We are grateful to all participants and to all people from our own department who helped with the organization.


"Hello" from the Field

15/12/2015

From October to December, most of our group spent time in Peru and Brazil doing field work on amphibians in floating meadows, pan-Amazonian poison frogs and harlequin frogs. People obtained data for ongoing research projects on species and range evolution of amphibians in terra firme and várzea systems. In harlequin frogs (Atelopus), we study the interplay of warning colors and toxicity. Most enthralling to us is that certain populations are overall cryptically colored but have bright red hand and foot soles which are shown while moving. We refer to this as flash marks. Field work will be continued in 2016.

Disentangling Chemical Communication in Poison Frogs: Cues & Signals

01/07/2015

Poison frogs show a complex parental care behavior. Several species lay eggs on land and later transport the tadpoles on one parent's back singly to small water bodies in plants (phytotelms). For some years now, it is known that Ranitomeya variabilis from the Amazon rainforest of Peru (and maybe other species) only choose phytotelms that are unoccupied by conspecific tadpoles and sometimes by those of other species (such as commonly Hyloxalus azureiventris). First the small water bodies do not provide resources for the development of more than one larva. Second, Ranitomeya larvae are cannibals and would attack each other. In our earlier studies, carried out by Dr. Lisa M. Schulte, we showed that nurse frogs chose the right phytotelm on the basis of chemical recognition (Schulte et al. 2011). This opened an avenue for further research questions.

We are a remarkable step further now! Combining chemical analyses with in-situ bioassays, we identified the molecular formulas of the chemical compounds triggering the nurse frog's behavior (collaboration was with the Helmholtz Centre for Environmental Research - UFZ; fundig was by the German Research Foundation - DFG). Ranitomeya variabilis and Hyloxalus azureiventris both produce distinct chemical compound combinations. This leads us to conclude that two separate communication systems are at work. In an ecological context, we classify the conspecific R. variabilis compounds as chemical cues - that is, they are only advantageous to the receiver (nurse frog), not the emitters (tadpoles). The heterospecific compounds, we suggest are chemical signals. These are advantageous to the emitters (heterospecific tadpoles) and likely also to the receivers (nurse frog). Due to these assumed receiver benefits, the heterospecific compounds are possibly synomones which are advantageous to both emitter and receiver. This is a very rare communication system between animal species, especially in vertebrates. Read more in the 1st July issue of PLoS ONE (Schulte et al. 2015).

Schulte, L.M. et al. (2015): Decoding and discrimination of chemical cues and signals: Avoidance of predation and competition during parental care behavior in sympatric poison frogs. — PLoS ONE 10: e0129929.

 

Alarming Research Results: Dramatic Threat by New Salamander Fungus

31/10/2014

A novel skin-eating fungal disease discovered in Europe poses a major threat to native salamanders and newts.
Batrachochytrium salamandrivorans (Bs) was discovered only in 2013 by researchers investigating a remarkable decline in Fire salamander populations in the Netherlands.

New research, involving a global screening of more than 5,000 amphibians (under the lead of An Martel and Frank Pasmans from Gent University, Belgium, involving members from our group), now suggests that the new disease presents a serious threat to many species. Bs is very dangerous to most salamanders and newts, but not to frogs, toads and the snake-like amphibians called caecilians. The fungus was also found in newts from Thailand, Vietnam and Japan as early as 1894, without causing disease, suggesting Bs originates from Southeast Asia. Read more in a press release by Trier University (in German) or watch our movie (in German).

Apparently, Bs has arrived in Europe only recently so far the disease has only been found in the Netherlands and Belgium, but it is likely to reach other European countries soon. In 2014, our group has started a Bs and salamander / newt population monitoring and research program in the area in Germany close to the Belgian and Dutch outbreaks. This will be continued into 2015 and on.

Martel, A. et al. (2014): Recent introduction of a chytrid fungus endangers Western Palearctic salamanders. — Science, 346: 630-631.


Europe Needs a New Vision for a Natura 2020 Network

05/02/2013

Advocating this statement, members of our group have contributed to an important and widely acknowledged policy piece published under the interdisciplinary graduate school 'Cooperation of Science and Jurisprudence in Improving Development and Use of Standards for Environmental Protection – Strategies for Risk Assessment and Management’ at Trier University, funded by the German Science Foundation DFG (GRK 1319). Read more (in German).

Hochkirch, A. et al. (2013): Europe needs a new vision for a Natura 2020 network. — Conservation Letters, 6: 462-476.