Ref. 2018Agro6

On-line application form

Supervisor name and surname:
Jonàs Oliva

Supervisor mail:

Title of the research project:

Plant‐soil feedbacks and tree diversity

Description of the research project:

Tree diversity has been associated with increased productivity, higher biodiversity, and larger aesthetic and landscape values. However, the very mechanism by which tree diversity is created and maintained in nature is not well understood. Recent work in tropical forests suggests that tree diversity is driven by negative plant-soil feedbacks caused by soil pathogens. The current paradigm states that as a tree species becomes dominant, specific pathogens for the dominant species also increase. This shift in soil microorganisms gives an advantage to rare tree species, thus preventing the expansion of a single species and favouring tree mixture. Nevertheless, soil microbiota may also cause positive feedbacks, as for instance, bacteria or mycorrhizal fungi may favour conspecific mixtures, and therefore counteract negative feedbacks caused by pathogens. As we move away from the tropical area, the direction of the feedbacks may also be influenced by abiotic factors.

In our group, we aim at studying plant soil feedbacks in global context and to use metagenomics to assign feedbacks to specific microbial species or to functional genes. In order to address this question, University of Lleida (UdL) is leading an international initiative to study plant-soil feedbacks in collaboration with the Swedish University of Agricultural Sciences in Uppsala (Sweden), and the Washington University in St. Louis (US). In this consortium, we are setting a global gradient of experiments, ranging from boreal to temperate, Mediterranean or tropical environments to explore how soil microbial communities and specifically pathogens drive aboveground diversity. The candidate will work in the Mediterranean part of the project, and will contribute to the other parts as well. The PhD will consist of three projects, one in which an experimental setup will test at which phylogenetic level plant‐soil feedback operates (genus or species), in which pine‐oak combinations will be used as model mixtures. Another project will consist in studying which pathogens are specific of each species by comparing mixed and pure stands of several tree species in Spain. The third project will consist in exploring the use of functional genes in order to describe pathogen communities in the soil.
Within Campus Iberus, the project will have an impact on the agro‐alimentary and nutrition sector. Microbes drive forest dynamics and diversity and thus contribute to the sustainability of forest ecosystems in the Ebro Valley. Forests in this area have both protective and productive functions and are a fundamental part of the agro‐economy cluster. Understanding forest dynamics, and how is this process shaped by microbes, will improve our capacity to predict the effects of global change, and to undertake more efficient adaptive measures, so forests can keep delivering goods and services to the society in future. 

PHD Programme:

Forest and the Environment Management

Universitat de Lleida

Supervisor short biography:

2017‐ “Ramon y Cajal” fellow, UdL, Spain.

2015‐ 2017 Associate Professor (Docent), Swedish University of Agricultural Sciences (SLU), Sweden.

2011‐ 2015. Assistant Professor, SLU, Sweden.

2008 ‐ 2011. Postdoc, SLU, Sweden.

2007. PhD, UdL, Spain.

Publication record:

JCR articles: 37 (23 in the last 5 years). Total citations (last 5 years): 332 (106 citations/year in last 3 years including 2018) (Scopus) Thesis supervised in the last 5 years: 1 finished, 1 ongoing. H index: 13 (Web-of-Science).


The goal of our lab at the UdL is to study broad ecological questions with links to practical needs, so to help agricultural and forest sectors to take decisions based on facts. Our core skills are the use of advanced molecular tools, such as high-throughput sequencing technologies, and the establishment of pathogenicity experiments.

Gross annual salary:

22.000-26.000 €

The employment contract in each recruiting institution will apply internal rules so final retribution might slightly differ.

Working hours:
37,5 hours a week

Full time