Nahla Lucchini is a PhD candidate at the Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO) in Portugal. She is an evolutionary ecologist with a special focus on the biogeographical dynamics of reptiles. Here, Nahla shares her recent work on climatic adaptation and diversification in European vipers.
Nahla sampling vipers in Morocco
Institute. CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Vairão, Portugal
Academic life stage. PhD Candidate
Major research themes. Evolutionary ecology; Biogeography; Herpetology
Current study system. For my PhD, I am working with European Vipers (genus Vipera) – a monophyletic group of small- to medium-sized viviparous, venomous snakes. The genus includes three main parapatric clades and 27 lineages that diversified around the Mediterranean Basin and adjacent areas, some of which exhibit cold-adapted physiology, while others are considered warm-adapted. Being ectotherms, they have a low dispersal ability compared to other vertebrates, which makes them highly vulnerable to climatic changes. All these traits make this group of vipers a unique system to study diversification dynamics in relation to niche evolution, particularly in one of the world’s biodiversity hotspots, the Mediterranean Basin.
Recent JBI paper. Lucchini, N., Kaliontzopoulou, A., Lourdais, O., & Martínez-Freiría, F. (2023). Climatic adaptation explains responses to Pleistocene oscillations and diversification in European vipers. Journal of Biogeography, 00, 1–14. https://doi.org/10.1111/jbi.14694
Motivation behind this paper. Understanding how ecological factors promote species diversification is still a hot topic in ecology and evolutionary biology. In fact, the role of niche divergence and niche conservatism during speciation is not a minor matter, as it can impact species persistence and the colonization of new geographical areas. In the case of European vipers, although there are some regional studies on selected species addressing the evolutionary history or the role of climate during their diversification, no comprehensive study has yet investigated the eco-evolutionary dynamics of the whole genus Vipera. In this recent paper, we delimited the climatic requirements of each lineage to understand their responses to Pleistocene climatic oscillations and to identify the evolutionary mechanisms underlying their diversification.
Key methodologies. One major strength of our work was the combination of various advanced techniques, such as Ecological Niche Modeling, phylogenetic comparative methods, and niche overlap analyses. These techniques allowed us to investigate, for the first time, how climatic niche evolution or conservatism shaped the diversity of European vipers. By employing this integrative, multifaceted approach, we were able to demonstrate that climatic adaptation acted as a primary driver of diversification in this group, resulting in a complex pattern of niche divergence along the viper’s phylogeny.
Vipera latastei, Spain.
Unexpected challenges. Possibly the main challenge was compiling a representative set of occurrence data for each individual lineage, including the lesser-known ones, for which distribution records were not easy to find at all. During the process of data compilation, I ended up mining several papers written in different languages and alphabets that were not familiar to me, such as many papers in Cyrillic. That was definitely a struggle! However, validating the information found in the maps helped me learn about many different places across the globe.
Major results. We found that climatic adaptation was a key element driving diversification among European vipers. Cold-adapted and warm-adapted lineages presented similar climatic requirements, based on their geographical origins. Among the three main Vipera clades, lineages belonging to the Pelias clade can be considered cold-adapted, while those within Vipera 1 and Vipera 2 clades are generally warm-adapted. However, closely related lineages responded differently to the Pleistocene climatic oscillations, suggesting that other factors have defined their recent range dynamics. Additionally, the phylogenetic signal analysis suggested adaptation to some environmental conditions. All these results together suggest an intricate pattern of niche divergence along the phylogeny that favors a scenario of local adaptation rather than Phylogenetic Niche Conservatism.
Vipera monticola, Morocco
Next steps for this research. I’m currently working on the integration of complementary methodologies, such as the application of mechanistic modelling considering the eco-physiological tolerances of the different species, to corroborate (or not) the climatic specialization patterns that we detected in this work and develop an in-depth investigation of range dynamics.
If you could study any organism on Earth, what would it be? I’m definitely happy with reptiles and snakes specifically, but I’ve also been particularly fascinated by tropical habitats, their complexity and the abundance of intriguing organisms to explore. Mixing the two would be amazing! Moreover, the challenges posed by habitat loss, climate change and human interaction make the study of tropical reptiles extremely urgent. By comprehending their biology and ecology, we can better inform conservation efforts and ensure the preservation of these remarkable creatures and the delicate ecosystems they call home.