Effects of increasing temperatures on reproduction in the Lesser Kestrel (Falco naumanni) and its conservation implications

In the next two decades anthropogenic-induced climate change is expected to cause an increase in average global temperatures reaching 1.5°C above pre-industrial levels, and may further accelerate under a business-as-usual CO2 emissions scenario. Alongside these increases in the average temperature, climate change is projected to increment the frequency and extent of extreme heat events (i.e. heatwaves). These events will significantly impact land surfaces, placing a considerable pressure on organisms living close to their thermal limits. Climate change trends are not geographically uniform. For example, the Mediterranean, a transition zone between arid and temperate climates, is forecasted to experience strong climate shifts towards increasing average temperatures compared to other parts of the world. At the same time, the Mediterranean region is a hotspot of biodiversity, and therefore represents a natural laboratory for studying wildlife responses to climate warming. This thesis sheds light on the influence of nest temperature (and thus, nest microclimate) on different aspects of reproduction, directly and indirectly influencing offspring condition andxiii survival; the role of nest temperature on temporal phenotypic changes observed in many bird populations in response to climate warming; and assesses whether selection for heterozygosity may ameliorate population resilience in case of numerical declines associated with extreme heat events. Given the widespread use of nest boxes in bird conservation policies, and the forecasted changes in climate in the upcoming decades, our results also highlight the need to properly design nest box characteristics to mitigate the negative effects of heatwaves on nest microclimate, and hence on reproductive success, in bird species whose conservation strongly depends on the availability of artificial nesting sites.