The Doñana Biological Station offers five contracts to develop the doctoral thesis.
The duration of the contracts will be 4 years with a dedication of 40 hours per week.
Potential candidates should contact the PI of the project to discuss their interest. To be eligible for one of these contracts, the candidate must have a master's degree, be admitted and enrolled to a doctoral program in a Spanish University.
Origin and impact of chromosomal inversions on the evolution and physiology of common quails
Principal Investigator: Carles Vilà
Chromosomal inversions result in the linkage of genes through reduced recombination. These are inherited as supergenes that evolve independently in individuals with and without the inversion, resulting in two divergent lineages. Recent advances in genomics research has facilitated the identification and characterization of these genomic rearrangements, and they are increasingly seen as a mechanism for diversification and adaptation.
In our previous project we described the presence of very large inversion, including more than 10% of the genome, in common quails (Coturnix coturnix). This inversion produces clear phenotypic characteristics in the individuals that carry it: darker throat coloration, slightly bigger size, rounded wings less suitable suitable for long flight, and reduced migration. This inversion could be associated with the uniqueness of some island quail populations and the study system represents a unique opportunity to investigate a mechanism of sympatric differentiation. However, little is known about the origin and evolutionary significance of this inversion.
With this project we will study the potential origin of the inversion through introgression of a different lineage, extant or extinct, or from one of the currently isolated populations in Africa. We will also study the impact that the inversion may have had on the evolution of quails and on their migratory behavior.
Aquatic birds as dispersal vectors of plastics and ecotoxic-epidemiological implications: the role of trophic ecology and movement (IsoPlastic)
Principal investigators: Manuela Forero y Marta Sánchez
Isoplastic project aims to assess the role of aquatic birds as biovectors of plastics and their ecotoxic-epidemiological implications, and the effect of key ecological behaviour as foraging movements and trophic ecology. We propose a multidisciplinary approach, combining Dispersal Ecology, Foraging and Trophic Ecology, Microbiology and Clinical Pathology.
We focus on three generalist bird species highly associated with anthropogenic habitats and with different trophic habits: white stork, yellow-legged gull and cattle egret. We will test the hypothesis that populations more associated with human related habitats carry more plastic waste to natural habitats and will have higher levels of toxicants associated to health problems. We will quantify the plastic load from anthropogenic habitats to wetlands through the analysis of faeces, pellets and nests content, and will relate this information with the diet and foraging movement patterns of individuals. Stable isotope analysis will be used to evaluate diet, trophic level and niche size of birds.
The project will also explore the understudied ecotoxicological dimension of plastic pollution by assessing the levels of plasticizers and flame retardants in bird tissues and their effects on blood chemistry and morphometry as indicatives of bird health. IsoPlastic will improve the global assessment of plastic pollution risk in ecosystems generating knowledge on poorly understood aspects such as transport, toxicology and epidemiology.
Increasing the resilience of High Nature Value pastoral systems hosting wild and domestic ungulates
Principal investigator: Luis Santamaría
Pastoral livestock production systems are present in many areas of the world, often in areas of High Nature Value, including many protected areas. In these areas, livestock practices must seek a balance that ensures both the long-term sustainability of the farm and the conservation of the ecosystems that support it. In areas of pronounced seasonality, such as the Atlantic and Mediterranean regions of Europe, achieving this balance is particularly difficult due to perceptual and management constraints caused by large climatic fluctuations (e.g. temperature and precipitation), both seasonal and inter-annual, which in turn cause large changes in plant production.
The solution to this dilemma is complex, involving either the use of very conservative stocking rates (low enough to avoid overgrazing in dry years) or the development of flexible systems based on dynamic adjustment of stocking rates and space use by livestock (and/or wild ungulates) in response to changes in plant production. The development of such strategies and tools is particularly valuable today, as climate change will exacerbate extreme weather events, causing an amplification of the processes described above. The RESILGRAZE project proposes to combine an interdisciplinary battery of study methods and techniques.
Effects of fire on ants at the ecosystem level. Mediterranean resilience?
Principal Investigators: Xim Cerdà y Paco Azcárate
The thesis is part of the PGC project (PID2022-138420NB-I00) "Short- and medium-term ecosystem effects of fire. Arthropods, mammals, plants and soil: Mediterranean resilience?" and focuses on how fire affects the organisation of ant communities, their participation in food webs and ecosystem functions.
Working areas: burned pine forests of the Central and Andalusian systems, and plots of scrubland in the Doñana Biological Reserve that were subjected to prescribed burning. The specific objectives are: Is there an effect of the age or geographical location of the fire on the organisation, structure and functionality of ant communities? Does the presence of ant mounds have a different effect on the physico-chemical properties of burned and unburned soils, and does this effect depend on the ant species? After the fire, is the participation of ants in the different trophic interactions modified? Does the age since the fire influence these modifications? Do ants participate in some processes of vegetation regeneration after the fire, and does this participation vary according to the time since the fire?
A graphical summary of the thesis research project (11 slides; 16Mb) can be downloaded at: https://docs.google.com/presentation/d/115JBkZYDWTWKTjHMCDo8NyPX_rk8CylJ/edit?
Exploitation and cooperation in temporally and spatially-structured seed-disperser mutualisms: integrating functional webs and spatially explicit individual-based modelling
Principal Investigator: José María Fedriani
The influence of mutualisms on the diversification of life transcends levels of biological organisation: from cells to populations, communities and ecosystems. Mutualisms are crucial for the reproduction and survival of countless plant and animal species. Moreover, mutualisms are progressively becoming a higher priority for conservation because of the essential ecosystem services they provide and because, at the same time, their ecological and evolutionary persistence is at risk. Recent research has shown that the temporal sequence in which cooperation and exploitation occur within mutualisms can strongly impact the costs of being exploited. Specifically, it has been predicted that exploitation occurring after cooperation generates lower costs than when exploitation occurs before cooperation. However, for most mutualisms, this prediction has never been tested.
In this pre-doctoral project we will investigate the impact that the temporal sequence of interactions between and within exploiters and mutualists has on seed dispersal success as well as the spatial patterns of recruitment and establishment of five plant species. To this end, we will use an experimental design in which the activity of several functionally diverse frugivores will be manipulated by selective exclusions. We will also empirically estimate habitat-to-habitat variation in the activity of exploiters and mutualists. Using spatially explicit individual-based models, we will estimate the habitat-dependent effects of interactions between seed dispersers and exploiters on local patterns of seedling recruitment and establishment. For this project we will select five common seed disperser-plant mutualisms in Doñana National Park (Huelva, southwestern Spain). These include a nut-bearing shrub (Halimium halimifolium), an acorn-producing tree (Quercus suber) and three fleshy fruit species (Corema album, Chamaerops humilis, and Pyrus bourgaeana).