Germán Orizaola

Associate professor

Instituto Mixto de Investigación en Biodiversidad
Universidad de Oviedo – Campus de Mieres
Edificio de Investigación – 5ª planta
c/ Gonzalo Gutiérrez Quirós s/n
33600 Mieres, Asturias. Spain.

Tel.:+34 985103000 (Ext. 5932)

Academic history

I was born in Santander (Spain) on the 15th August 1974. I finished my degree studies in Biology (Zoology) at the University of Oviedo (Spain) in 1997.

I conducted my thesis work at the University of Oviedo (Spain), under the supervision of Florentino Braña, examining the ecological interactions between introduced fish and amphibians.  I defended my PhD thesis in 2004.

I conducted my postdoc between 2005-2011, in the group of Anssi Laurila at the Population and Conservation Biology Unit, Uppsala University, where I examined the microgeographic variation of crucial life-history traits and the evolutionary potential of small and isolated populations, using the Swedish pool frog (Pelophylax lessonae) as study model. During this time, I also examined the determinants of growth and development across latitudinal gradients in amphibians. I worked as Associate Researcher in Animal Ecology, Dept. Ecology and Genetics, Uppsala University between December 2010-May 2018.

Since June 2018, I work as Senior Researcher (Ramón y Cajal Program) at the University of Oviedo, Spain. Here, I am affiliate to the Zoology Unit and the Research Unit of Biodiversity-IMIB (joint centre between the University, the Spanish Research Council-CSIC, and the Principality of Asturias). Here, I maintain a research program examining the effects that environmental variation, and in particular extreme environments, have on the evolutionary ecology and life-history strategies in organisms with complex-life cycles. Current projects deal mostly with the effects of low-dose radiation, altitude and latitude in a diverse range of genomic, physiological and ecological traits of amphibians.

Here are my Google Scholar, ResearchGate and ID-Researcher pages.

Research interests

I am an evolutionary ecologist interested in understanding how organisms respond to environmental stress. In my research, I combine field studies with common garden experiments and laboratory analyses, using amphibians as study models. My current research topics are:

Effects and adaptation patterns to low-dose radiation in wildlife

I have recently started to examine the impact of chronic exposure to low-dose ionizing radiation in wildlife. Specifically, this research line investigates the effects of chronic exposure to human-released ionizing radiation on natural populations of amphibians in Chernobyl. Examining how amphibians cope with the chronic exposure to low-dose ionizing radiation can shed light on the debate over the effects of, and possible adaptive responses to, exposure to low-dose radiation in nature. I am using the European treefrog (Hyla arborea) living in the Chernobyl Exclusion Zone as the study model, analysing how treefrogs respond to biological damage as a consequence of living in areas contaminated by radiation. I am analyzing how amphibians respond to radiactive contamination by  comparing different aspects of the genetics, development and physiology of frogs living inside and outside areas affected by radioactive fallout from the Chernobyl accident in 1986.

Evolutionary ecology of life-history strategies

This research line examines the impact of phenological variation on life history strategies in amphibians. In particular, I have examined the extent, costs and limits of plastic growth and development in amphibian larvae in a context of increasing phenological fluctuation. Main achievements of this line include the identification of the first unequivocal evidence for transgenerational plasticity in response to changes in breeding phenology in vertebrates; the identification of costs paid in offspring exhibiting fast development in response to delayed breeding phenology (e.g. reduced immune response and antipredator defences), and the impact that intra-specific priority effects have on the generalization of these responses.

At present, I am paying particular attention to the impact of phenological shifts on amphibian skin microbiome, and how this can be related to disease susceptibility. In particular, I am examining the variation in the amphibian skin microbiome across environmental gradients that lead to very different levels of time constraints (e.g. latitudinal and altitudinal gradients). Within this framework, I am also trying to identify probiotic microorganisms in the amphibian skin microbiome (i.e. the skin bacteria that kill fungus pathogens most effectively). I am also investigating the patterns of skin microbiome acquisition in amphibians due to its impact on the implementation of captive breeding programs effective at maintaining microbial diversity and, thus, health in amphibians.

Eco-evolutionary effects of invasive species

The effect that the introduction of exotic species is causing in natural environments has become one of the main environmental concerns of our time. In particular, introduced predators have been identified as one of the factors contributing to the observed global amphibian decline. During my PhD at the University of Oviedo, Spain,  I examined the impact that the introduction of predatory fish (mainly salmonids) have on the distribution, reproductive behaviour and larval development of amphibians, focusing on their impact on several newt species.


My current position as Senior Researcher is funded by the «Ramón y Cajal Program» of the Spanish Ministry of Science, Innovation and Universities. I maintain additional research projects currently funded by the Swedish Radiation Safety Authority, Carl Tryggers Stiftelsen and Stiftelsen för Zoologisk Forskning. I am also collaborating in the projects “Exploring the amphibian skin microbiome: ecological correlates and probiotic use to enhance disease resistance” funded by BBVA Foundation (August 2016, PI: Alfredo G. Nicieza, Univ. Oviedo). I recently participate in the project “COordination and iMplementation of a pan-Europe instrumenT for radioecology project” funded by EU-FP7 (June 2013, PI: Hildegarde Vandenhove, Belgian Nuclear Research Centre).

Previous research activities were funded by the Spanish Ministry of Education and Science, Fundación Ramón Areces, Fundación Caja Madrid, Swedish Royal Academy of Sciences, Oscar och Lili Lamms Minne Stiftelse and Helge Ax:son Johnsons Stiftelse.



  • 42. Car, C., Gilles, A., Armant, O., Burraco, P., Beaugelin-Seiller, K., Gashchak, S., Camilleri, V., Cavalie, I., Laloi, P., Adam-Guillermin, C., Orizaola, G. and Bonzom, J.-M. 2021. Unusual evolution of tree frog populations in the Chernobyl exclusion zone. Evolutionary Applicationsin press.

  • 41. Burraco, P., Car, C., Bonzom, J.-M. and Orizaola, G. 2021. Assessment of exposure to ionizing radiation in Chernobyl tree frogs (Hyla orientalis). Scientific Reports, in press.

  • 40. Burraco, P., Bonzom, J.-M., Car, C., Beaugelin-Seiller, K., Gashchak, S. and Orizaola, G. 2021. Lack of impact of radiation on blood physiology biomarkers of Chernobyl tree frogs. Frontiers in Zoology 18, 33. LINK

  • 39. Burraco, P.,  Laurila, A. and Orizaola, G. 2021. Limits to compensatory responses to altered phenology in amphibian larvae. Oikos 130, 231-239. LINK
  • BOOK CHAPTER. Orizaola, G. 2021. Amphibians in field radioecology: a review and perspective. In: Biomarkers of radiation in the environment – Robust tools for risk assessment (eds. M. D. Wood, C. E. Mothersill, G. Tsakanova, T. Cresswell, and G. E. Woloschak). NATO Science for Peace and Security Series A: Chemistry and Biology. Springer, in press..

  • BOOK CHAPTER. Orizaola, G. 2021. Chernobyl has become a refuge for wildlife thirty-three years after the nuclear accident. In: No, you’re not entitled to your opinion, and 49 other essays that got the world talking (A. Hansen, ed.), in press.


  • 38. Burraco, P., Orizaola, G., Monaghan, P. and Metcalfe, N. 2020. Climate change and ageing in ectotherms. Global Change Biology 26, 5371-5281. LINK.

  • 37. Johansson, F., Orizaola, G. and Nilsson-Örtman, V. 2020. Temperate insects with narrow seasonal activity periods can be as vulnerable to climate change as tropical insect species. Scientific Reports 10, 8822. LINK.

  • 36. Burraco, P., Valdés, A. E. and Orizaola, G. 2020. Metabolic costs of altered growth trajectories across life transitions in amphibians. Journal of Animal Ecology 89, 855-866. LINK

  • 35. Beresford, N., Horemans, N., Copplestone, D., Raines, K.E., Orizaola, G., Wood, M.D., Laanen, P., Whitehead, H.C., Burrows, J.E., Tinsley, M.C., Smith, J.T., Bonzom, J.-M., Gagnaire, B., Adam-Guillermin, C., Gashchak, S., Jha, A.N., de Menezes, A., Willey, N. and Spurgeon, D. 2020. Towards solving a scientific controversy – The effects of ionising radiation on the environment. Journal of Environmental Radioactivity 211, 106033. LINK

  • 34. Orizaola, G. 2020. From nuclear desert to evolutionary lab: the response of living organisms to Chernobyl’s ionising radiation. Mètode Science Studies Journal 10, 193-199. LINK


  • 33. Lindgren, B., Orizaola, G. and Laurila, A. 2018. Interacting effects of predation risk and resource level on escape speed of amphibian larvae along a latitudinal gradient. Journal of Evolutionary Biology 31, 1216-1226. LINK


  • 32. Murillo-Rincón, A. P., Laurila, A. and Orizaola, G. 2017. Compensating for delayed hatching reduces offspring immune response and increases life-history costs. Oikos 126, 565-571. LINK
  • 31. Murillo-Rincón, A. P., Kolter, N. A., Laurila, A. and Orizaola, G. 2017.  Intra-specific priority effects modify compensatory responses to changes in hatching phenology in an amphibian. Journal of Animal Ecology 86, 128-135. LINK


  • 30. Carreira, B., Segurado, P., Orizaola, G., Gonçalves, N.,  Pinto, V., Laurila, A. and Rebelo, R. 2016. Warm vegetarians? Heat waves and diet shifts in tadpoles. Ecology 97, 2464-2474. LINK
  • 29. Orizaola, G., Richter-Boix, A.and Laurila, A. 2016. Transgenerational effects and impact of compensatory responses to changes in breeding phenology on antipredator defenses. Ecology 97, 2470-2478LINK
  • 28. Orizaola, G. and Laurila, A. 2016. Developmental plasticity increases at the northern  range margin in a warm-dependent amphibian. Evolutionary Applications 9, 471-478. LINK (Open Access).
  • 27. Dijk, B., Laurila, A., Orizaola, G. and Johansson, F. 2016. Is one defence enough? Disentangling the relative importance of morphological and behavioural predator induced defences. Behavioral Ecology and Sociobiology 70, 237-246. LINK


  • 26. Orizaola, G. and Valdés, A. E. 2015. Free the tweet at scientific conferences. Science 350, 170-171. LINK


  • 25. Richter-Boix, A., Orizaola, G. and Laurila, A. 2014. Transgenerational phenotypic plasticity links parental phenology with offspring life-history. Ecology, 2715-2722. LINK
  • 24. Nunes, A. L., Orizaola, G., Laurila, A. and Rebelo, R. 2014. Rapid evolution of constitutive and inducible defenses against an invasive predator. Ecology 95, 1520-1530. PDF (pre-print)
  • Photo Galley at ESA Bulletin 95, 451- 456 PDF
  • 23.  Nunes, A. L., Orizaola, G., Laurila, A. and Rebelo, R. 2014. Morphological and life-history responses of anurans to an invasive predator: an integrative approach. Ecology and Evolution 4, 1491-1503 (Open Access LINK).
  • 22. Orizaola, G., Dahl, E. and Laurila, A. 2014. Compensatory growth strategies are affected by the strength of environmental time-constraints in anuran larvae. Oecologia 174, 131-137. PDF


  • 21. Orizaola, G., Dahl, E., Nicieza, A.G. and Laurila, A. 2013. Life history and anti-predator strategies are affected by breeding phenology in an amphibian. Oecologia 171, 873-881. PDF


  • 20. Dahl, E., Orizaola, G., Nicieza, A.G. and Laurila, A. 2012. Time constraints and flexibility of growth strategies: geographic variation in catch-up growth responses in amphibian larvae. Journal of Animal Ecology 81, 1233-1243. PDF
  • 19. Dahl, E., Orizaola, G., Windberg, S. and Laurila, A. 2012. Geographic variation in corticosterone response to chronic predator stress in tadpoles. Journal of Evolutionary Biology 25, 1066-1076. PDF
  • 18. Orizaola, G., Dahl, E. and Laurila, A. 2012. Reversibility of predation-induced plasticity and its effect at a life history switch point. Oikos 121, 44-52. PDF


  • 17. Arce, F., Orizaola, G. and Navedo, J.G. 2011. Storm petrel´s breeding skipping in response to oil-spill pollution: Raising concerns over Zabala et al. (2011) methodological approach. Marine Pollution Bulletin 62, 2576-2577. PDF


  • 16. Tejedo, M., Marangoni, F., Pertoldi, C., Richter-Boix, A., Laurila, A., Orizaola, G., Nicieza, A.G., Álvarez, D. and Gómez-Mestre, I. 2010. Contrasting effects of environmental factors during larval stage on morphological plasticity in post-metamorphic frogs. Climate Research 41, 31-39. PDF
  • 15. Navedo, J.G., Orizaola, G., Masero, J.A., Overdijk, O. and Sánchez-Guzmán, J.M. 2010. Long-distance travellers stopover for longer: a case study with spoonbills staying in North Iberia. Journal of Ornithology, 151, 915-921. PDF
  • 14. Orizaola, G., Quintela, M. and Laurila, A. 2010. Climatic adaptation in an isolated and genetically impoverished amphibian population. Ecography 33, 730-737. PDF
  • 13. Orizaola, G., Dahl, E. and Laurila, A. 2010. Compensating for delayed hatching across consecutive life-history stages in an amphibian. Oikos 119, 980-987. PDF
  • 12. Navedo, J.G., Masero, J.A., Overdijk, O., Orizaola, G. and Sánchez-Guzmán, J.M. 2010. Assessing the role of multiple environmental factors on Eurasian Spoonbill departure decisions from stopover sites. Ardea, 98, 3-12. PDF


  • 11. Orizaola, G. and Laurila, A. 2009. Microgeographic variation in temperature-induced plasticity in an isolated amphibian metapopulation. Evolutionary Ecology 26, 979-991. PDF
  • 10. Orizaola, G. and Laurila, A. 2009. Intraspecific variation of temperature-induced effects on metamorphosis in the pool frog (Rana lessonae). Canadian Journal of Zoology 87, 581-588. PDF
  • 9. Orizaola, G. and Laurila, A. 2009. Microgeographic variation in the effects of larval temperature environment on juvenile morphology and locomotion in the pool frog. Journal of Zoology 277, 267-274. PDF


  • 8. Orizaola, G. and Laurila, A. 2008. Growing with kin does not bring benefits to tadpoles in a genetically impoverished amphibian population. Canadian Journal of Zoology 86, 45-50. PDF


  • 7. Orizaola, G. and Braña, F. 2006. Effect of salmonid introduction and other environmental characteristics on amphibian distribution and abundance in mountain lakes of Northern Spain. Animal Conservation 9, 171-178. PDF


  • 6. Orizaola, G. and Braña, F. 2005. Plasticity in newt metamorphosis: the effect of predation at embryonic and larval stages. Freshwater Biology 50, 438-446. PDF *Front cover article*


  • 5. Orizaola, G. and Braña, F. 2004. Hatching responses of four newt species to predatory fish chemical cues. Annales Zoologici Fennici 41, 635-645. PDF


  • 4. Orizaola, G. and Braña, F. 2003. Response of predator-naive newt larvae to food and predator presence. Canadian Journal of Zoology 81, 1845-1850. PDF
  • 3. Orizaola, G. and Braña, F. 2003. Do predator chemical cues affect newt oviposition site selection? Herpetological Journal 13, 189-193. PDF
  • 2. Orizaola, G. and Braña, F. 2003. Oviposition behaviour and vulnerability of eggs to predation in four newt species (genus Triturus). Herpetological Journal 13, 121-124. PDF


  • 1. Braña, F., Frechilla, L. and Orizaola, G. 1996. Effect of introduced fish on amphibian assemblages in mountain lakes of northern Spain. Herpetological Journal 6, 145-148. PDF