Integrating agriculture and conservation: The value of fallow land and its management for farmaland and steppe bird conservation

• Autores: Ana Sanz Pérez
• Directores de la Tesis: David Giralt Jonama (dir. tes.), Francesc Sardà Palomera (codir. tes.), Santi Mañosa (tut. tes.)
• Lectura: En la Universitat de Barcelona ( España ) en 2021
• Idioma: inglés
• Tribunal Calificador de la Tesis: Aurèlien Besnard (presid.), Antonio Hernández Matías (secret.), Inês Catry (voc.)
• Programa de doctorado: Programa de Doctorado en Biodiversidad por la Universidad Autónoma de Barcelona y la Universidad de Barcelona
• Materias:
  • Ciencias de la vida
    • Biología animal (zoología)
      • Ecología animal
  • Ciencias agrarias
    • Ciencia forestal
      • Conservación
• Enlaces
  • Tesis en acceso abierto en: TESEO
• Resumen

  • Extensive farmland ecosystems are widespread and biodiversity-rich, yet they face important human pressures since the beginning of agriculture intensification, which is leading them into a severe biodiversity crisis. As a result, farmland bird populations - particularly specialist species such as steppe birds - are declining dramatically. In Europe, steppe birds are associated with “cereal steppes”, which are extensive agricultural landscapes where crop rotations include fallow fields. Fallows are key breeding and foraging habitats for farmland birds and usually present open vegetation structures essential for steppe birds. This thesis, situated in a cereal steppe in Catalonia (north-eastern Spain), evaluates the importance of fallow land and its management for enhancing farmland and steppe bird populations. Because population monitoring is key to evaluate the status of populations, I also explored the importance of accounting for imperfect detection when estimating farmland bird population trends. By using a Hierarchical Distance Sampling (HDS) model, I found that heterogeneous detection across observers and years could bias trend estimates when not accounted for. Through a HDS community model integrating data of 37 farmland bird species, I revealed the lack of efficiency of conservation measures applied in fallow fields, currently promoted by the European Common Agricultural Policy (Agri-Environmental Schemes and Greening), to increase farmland bird abundance. However, a local conservation measure targeted specifically at steppe birds (Targeted Fallow Management, TFM) – consisting of agricultural practices on fallows applied once or twice annually before the breeding season – enhanced steppe bird abundance. Through path analyses, I could disentangle the mechanisms behind TFM success and found that TFM fulfils species-specific requirements by modulating the vegetation structure. Finally, I used the first GPS data on the declining Pin-tailed sandgrouse (Pterocles alchata) to demonstrate the importance of fallow land during the breeding season, when cereal vegetation is tall and unsuitable for steppe birds causing a habitat bottleneck. This thesis provides applied guidelines for conservation planning, from population monitoring to mechanisms involved in the success of specific conservation measures. The key finding is the importance of promoting not only fallow-land presence, but also its management, to improve its conservation efficiency. These guidelines have great potential to be included within the upcoming European agricultural reform (CAP post-2020) and help prevent imminent population and species extinctions.