Demographic analysis and population models in ecology, evolution and conservation: a transversal approach with case studies = L’anàlisi demogràfica i els models poblacionals en ecologia, evolució i conservació: un enfoc transversal amb casos d’estudi

• Autores: Albert Fernández Chacón
• Directores de la Tesis: Daniel Oro de Ribas (dir. tes.), Carola Sanpera Trigueros (dir. tes.), Meritxell Genovart Millet (dir. tes.)
• Lectura: En la Universitat de Barcelona ( España ) en 2013
• Idioma: inglés
• Tribunal Calificador de la Tesis: Juan Carlos Senar (presid.), Santi Mañosa (secret.), Guillaume Souchay (voc.)
• Materias:
  • Ciencias de la vida
    • Biología animal (zoología)
      • Ecología animal
      • Zoología general
    • Antropología (física)
      • Biología de poblaciones
    • Biomatemáticas
      • Bioestadística
• Enlaces
  • Tesis en acceso abierto en:  TDX  Dipòsit Digital de la UB 
• Resumen

  • Population ecology is a scientific discipline primarily interested in the ecological processes that make the number of individuals in a population to change over space and time, and by focusing on populations as fundamental units, this discipline allows studying processes at multiple scales of ecological complexity, linking basic ecological science with evolutionary studies and more applied disciplines such as conservation biology. Inference about the responses of population to change are made via observational studies that focus at either the individual or population level in order to estimate key vital rates and to determine the primary drivers of system dynamics. However, a problem of observational studies is that quite often the ecological and observational processes are confounded, leading to biased estimates and wrong conclusions about a population, so more specific and robust analytical approaches need to be applied for a correct scientific study of the populations. In this thesis, I have consistently applied a methodological approach that allows the study of population processes by separating ecological and observational processes via the estimation and modelling of key demographic parameters. By means of chapters 1 to 4, I provide several examples of this methodology via the analysis of demographic data belonging to different species and levels of population complexity that also reflect different biological questions and scientific applications. Field data for this thesis was collected using either capture-recapture or detection-non detection sampling techniques and were provided via collaborations with different researchers and institutions. Chapters 1 and 2 focus on discrete mediterranean tortoise (Testudo hermanni) and brown trout (Salmo trutta) populations, respectively. These populations are closed to dispersal processes and in both chapters I focused on stage-dependent local survival rates that were estimated using capture-recapture models that take into account recapture probabilities. Given that individuals were classified according to body size, in the case of the brown trout populations, I could apply multistate capture-recapture models to estimate individual growth and maturation rates across different populations. In both chapters, survival dynamics were modelled using external covariates (temperature and/or precipitation) that explained part of the observed variation in survival. In the case of tortoises, the obtained survival-precipitation relationship was used to perform several population viability analyses under future precipitation scenarios to forecast the extinction risk of the species across their global geographic distribution. Chapters 3 and 4 focus on population networks connected by dispersal processes. Chapter 3 is strictly focused on adult dispersal and so analyses a capture-recapture dataset collected over 4 local populations of Audouin’s gull (Larus audouinii) in the Western Mediterranean. In Chapter 4 I analysed a large database on butterfly species collected at 26 sites in Catalonia over 17 years and focused on species’ extinction-colonization dynamics at a large geographical scale. In both chapters, two relatively recent analytical approaches, the multievent modelling (chapter 3) and the multiseason or dynamic occupancy modelling (chapter 4) were applied. The application of such modelling tools allowed, in the case of gulls, to control recapture heterogeneities and to study individual dispersal both in and out of the study area, by means of the addition of unobservable states in the model. In the case of butterflies, a common candidate model set was applied to 73 butterfly species, obtaining specific extinction and colonization rates corrected for species’ detectability, which allowed assessing the influence of the species’ traits on occupancy dynamics. Covariate modelling became much more complex in these chapters, but allowed the identification of different habitat and environmental variables related to dispersal, extinction and colonization processes that are of high value in the conservation and management of the species under study.