The evolutionary relevance of behavioral traits has been largely debated among biologists. Behavioral changes often constitute the first response to changing environmental conditions. This suggests that behavioral variation among individuals within a population potentially represents the raw material for natural selection, ultimately determining the ecological and evolutionary responses to new selective pressures. However, the genetic basis of behavioral traits remains largely unknown. This uncertainty limits our understanding of the role of behavior in shaping the adaptive potential of natural populations. In this project I aim to uncover the molecular underpinnings of risk-taking behavior, a key trait associated with survival in the lizard Anolis sagrei under new predation regimes. First, using restriction site-associated DNA sequencing (RADseq) data, I will characterize the heritability of risk-taking behavior by estimating its additive genetic variance based on multigenerational pedigrees of lizards that have undergone behavioral assessments. I will then search for genomic regions and variants associated with risk-taking behavior by FST outlier scans, selective sweep scans and genome-wide association study (GWAS) with the use of RADseq and whole-genome sequencing (WGS) data. Finally, using whole-genome bisulfite sequencing (WGBS) data, I will explore the impact of DNA methylation on the variation in risk-taking behavior to shed light on the role of epigenetic mechanisms in controlling animal behavior. By characterizing the genetic and epigenetic architecture of risk-taking behavior, riskADAPT will decisively advance our understanding of the role of ecologically-relevant behaviors in the evolutionary adaptation to rapid environmental changes.

Increases in atmospheric CO2 have resulted in significant changes in global climate and ecosystem processes. It is well known that the terrestrial biosphere fixes large quantities of carbon from the atmosphere. Still, less certain is whether soil and terrestrial vegetation can mediate the increase in CO2 and for how long. Carbon storage largely depends on water constraints, and climate models predict drier future conditions, particularly in the Mediterranean. Although droughts are associated with reductions in photosynthetic rates, their effect on the role of forests in climate change mitigation is still unclear. The Drought Impact on the Climate Benefit of Carbon Sequestration project aims to advance understanding of the impact of soil moisture on forests-avoided warming and for how long it occurs by achieving three objectives: i) simulate the effect of drought on the global terrestrial biosphere C cycle under global warming scenarios, ii) develop a mechanistic model based on experimental observations to represent the carbon cycle dynamics under drought conditions in a Mediterranean forest, and iii) compare the warming produced by CO2 emissions and that avoided by Mediterranean forests under drought scenarios. These objectives will permit answering whether the climate benefit of C sequestration is sensitive to drought conditions on a global and local (Mediterranean) scale and whether Mediterranean forests mantain their offset CO2 emissions under these conditions. The above will be carried out by linking photosynthesis, storage and respiration processes through the combination of Transit Time, Carbon Sequestration, and the Climate Benefit of Sequestration concepts with measurements from a unique long-term drought experiment, the compartmental system approach and global carbon cycle models. This project will result in relevant scientific contributions and a valuable and comprehensible tool to enhance policy-oriented discussion on nature-based climate mitigation.

Forest canopies play a significant role in regulating carbon and water exchanges with the atmosphere, with profound effects on our climate. However, their role in altering the chemical composition of precipitation and, consequently, the nutrient cycling within a forest has been less investigated. This is particular relevant for nitrogen (N)-limited forests in the Northern hemisphere, which have been exposed to a rapid human-induced increase in Ndep over the last decades. Much of the scientific attention has been focused on the role of Ndep in enhancing forest C-sink, while we still need to elucidate the fate of Ndep when entering forest and its contribution to N cycling. In particular, it is still not clear whether Ndep is retained, taken up and/or altered by biological transformations when interacting with tree canopies. By applying a quadruple isotope approach I recently demonstrated the occurrence of in-canopy biological nitrification of atmospheric N for UK forests at high Ndep. Hence, NITRIPHYLL intends to extend the multiple isotope approach a) to enlarge the range of conditions under which the process is demonstrated to occur, b) to investigate difference between species in the proportion of microbiologically-derived NO3 and c) the reasons of these differences. Furthermore, by using proteo-genomic techniques we aim to characterize phyllosphere microbial communities involved in canopy nitrification. We will consider i) forests along a gradient of climate and Ndep within the well established EU-ICP forest network and ii) existing N manipulation experiments. NITRIPHYLL for the first time merges two separate research avenues, i.e., the investigation of canopy nitrification with the study of the occurrence, abundance and diversity of bacteria communities in the phyllosphere. Thus, the project will contribute to providing a deeper understanding of how the phyllosphere affects the N, and consequently C, cycling within forests in relation to climate and Ndep.