Effects of environmental variation on the reproduction of two widespread cervid species

• Autores: Marta Peláez Beato
• Directores de la Tesis: Alfonso San Miguel Ayanz (dir. tes.), Ramón Perea García-Calvo (codir. tes.)
• Lectura: En la Universidad Politécnica de Madrid ( España ) en 2020
• Idioma: español
• Tribunal Calificador de la Tesis: Juan Carranza Almansa (presid.), Sonia Roig Gómez (secret.), Pelayo Acevedo Lavandera (voc.), María Martínez Jáuregui (voc.), Carlos Manuel Martins Santos Fonseca (voc.)
• Programa de doctorado: Programa de Doctorado en Investigación Forestal Avanzada por la Universidad Politécnica de Madrid
• Materias:
  • Ciencias de la vida
    • Biología animal (zoología)
      • Ecología animal
  • Ciencias agrarias
    • Peces y fauna silvestre
      • Dinámica de las poblaciones
• Enlaces
  • Tesis en acceso abierto en: Archivo Digital UPM
• Resumen

  • Populations living at the edge of a species' range of distribution often experience sub-optimal conditions and different selective pressures than those located at more central locations. Thus, in the context of climate change, edge populations may provide key information to understand the evolution of species under harsher climatic conditions, helping to predict future demographic changes and distribution shifts. Our main goal was to assess the effect of environmental variation on the reproduction of red deer (Cervus elaphus) and roe deer (Capreolus capreolus) populations living at the edge of their range (i.e. Mediterranean and Alpine ecosystems). This thesis is structured in three chapters that contain 6 research studies.

    Chapter I analyzed how environmental conditions affected female reproductive timing of both species. Study 1 revealed that red deer displayed high phenotypic plasticity in conception dates in Mediterranean environments, being population traits and the effect of climatic conditions on plant productivity the most influential factors. Thus, dry springs with low plant productivity and high densities produced delayed conception dates. Studies 2 and 3 assessed the ability of roe deer parturition timing to track environmental changes along two different axes: space and time. While roe deer parturitions were delayed with increasing latitudes and elevations, they displayed little plasticity to rapidly adjust them to the increasingly earlier plant phenology of Alpine environments. Chapter II studied the variation of demographic parameters along geographical gradients. Thus, study 4 showed an increase in roe deer litter size with latitude but a decrease with elevation. This opposite relationship, known as the fecundity gradient paradox, has never been reported for a large mammal. Finally, Chapter III analyzed how environmental conditions and individual factors influenced the development of male secondary sexual traits in Mediterranean environments. Study 5 indicated that population traits and food availability were the main factors influencing antler size in red deer, in line with Study 1. Finally, roe deer early-life investment on antlers was a reliable indicator of future adult performance (i.e. antler and body size) in Mediterranean environments (Study 6).

    Overall, the increasingly longer and more severe drought in Mediterranean areas and the advanced spring phenology and higher temperatures in Alpine locations induced by climate change may produce a misalignment between the timing of key reproductive events (i.e. parturition or antler formation) and the peak of plant productivity. Therefore, this could negatively impact the performance of red- and roe deer living in these environments.

    We highlight the importance of lowering red deer population density in Mediterranean environments to decrease the impact of severe drought events. Finally, the existence of evolutionary constraints for roe deer parturition dates along the elevational gradient advocates for adaptive management practices under the rapid climate change in Alpine environments.