The reproduction of many plants is characterized by mast seeding, where boom and bust seed production years are correlated amongst individuals over large spatial scales due to their common response to a climatic trigger. Masting is thought to have evolved to foil seed predators, whose populations shrink during non-mast years when seed availability is low and cannot grow fast enough to consume all seeds during mast years, allowing some seeds to ‘escape’ predation. However, many seed predators are generalist, so that a dearth of seeds of by one plant species can be made up by high seed production of another species – unless masting is correlated among members of the same plant community.

Moreover, the positive effects of high density at seed stages may be outweighed by negative competitive effects at seedling stages. Unfortunately, fully exploring these possibilities is difficult, as few studies consider masting in the context of an entire community, with multiple plant species and seed predators linked through seed predation, and few additionally follow the entire process of recruitment (from seed to successful seedling). 

Project background

To address this topic, the Plant Ecology Group at ETH Zürich, led by Professor Janneke Hille Ris Lambers (she/her), seeks a PhD student to explore the consequences of masting on the dynamics of a community of trees and seed predators in the coniferous forests of western Washington. Conifers dominate these forests, all of which exhibit mast seeding, and whose seeds are consumed by a community of generalist and specialist vertebrate and invertebrate seed predators.

Open questions include:
1) Do co-occurring conifers co-mast (exhibit a standard frequency and timing of mast events), and to what extent do co-occurring tree species share seed predators?
2) What are the implications of masting and co-masting for the demographic performance of co-occurring trees and seed predators?
3) How will climate change, which will alter community composition and possibly the frequency of masting, change these relationships?
Over a decade of long-term data on annual seed production, seedling recruitment, and tree demography from multiple locations within Mt. Rainier National Park (Washington State, USA) provides a unique data set and setting to address some of these questions.

Job description: You will work collaboratively with the Plant Ecology Group (consisting of Masters’s students, and research staff) on this project, taking a leadership role in the annual collection of long-term data from Mt. Rainier National Park (USA) and the analysis of this data. This will allow for interactions with collaborators at Mt. Rainier National Park and the University of Washington. Furthermore, you will also be allowed to develop their project(s) that fits within the overall project theme.

This project could be observational, experimental or analytical, and could take advantage of Mount Rainier field sites and/or newly established forest regeneration monitoring sites in Switzerland. A thematically similar PhD position (focused on tree seedling responses to extreme climates) will be filled at the same time, and it is likely that the two PhD students will benefit from collaboration with each other in data collection, methods development, and/or analysis. Professor Janneke Hille Ris Lambers will be the primary supervisor. 

Your profile

You have the following attributes:

  • Enthusiasm and interest in the scientific background of the project
  • Ability to work independently and collaboratively
  • Commitment to a collegial and inclusive workplace
  • Experience with statistical modelling and related programs (R statistics)
  • Field work experience and a valid driver’s license
  • Willingness to travel and stay in the US for data collection for 2-3 months
  • Advanced English (oral and writing)
  • Plant identification skills are desirable but not required

We offer

The Plant Ecology Group at ETH Zürich conducts research on a diversity of topics within the realm of plant community ecology, including forest community turnover in response to climate change, the role of climate, biotic interactions, and demographic lags in constraining population dynamics and range shifts, the drivers of Alpine wildflower phenology, and the use of citizen science for collecting ecological data and engaging the general public. We conduct projects and maintain long-term monitoring studies in forest and Alpine field sites in the USA (Washington State) and Switzerland. We are committed to fostering diversity and inclusivity in all our activities, as well as to conducting open and collaborative science..

Outstanding research groups at ETH Zürich, the adjacent University of Zürich, WSL (the Swiss Federal Institute for Forest, Snow and Landscape Research) and EAWAG (the Swiss Federal Institute of Aquatic Science and Technology) offer numerous opportunities for interaction and collaboration. Zürich is a cosmopolitan city with high living standards and easy access to forested and alpine research sites, outdoor activities and the rest of Europe.

We value diversity

In line with our values, ETH Zurich encourages an inclusive culture. We promote equality of opportunity, value diversity and nurture a working and learning environment in which the rights and dignity of all our staff and students are respected. Visit our Equal Opportunities and Diversity website to find out how we ensure a fair and open environment that allows everyone to grow and flourish.

Curious? So are we.

Application process: We look forward to receiving your online application, including the following documents, each uploaded as a separate pdf. Please include your last name in the title of any file uploaded (e.g. Aziz-CV.pdf, Chang-MscDegree.pdf, Garcia-MscTranscript.pdf).

  • Your curriculum vitae (2-page CV), including information on your educational background and any relevant research/work/volunteering activities
  • A copy of your MSc degree (including thesis title) and a list of courses taken and Grades (a transcript)

Applications will be reviewed starting September 15, to conduct interviews in early/mid-October and make a decision by early November. The ideal start date would be January of 2023. Please note that we exclusively accept applications submitted through this online application portal, and applications via email or postal services will not be considered. Incomplete applications will also not be evaluated.

Questions regarding the position can be directed to Dr Janneke Hille Ris Lambers ( Please include an informative subject (e.g. “Questions about Masting PhD position”). 

Apply online now

About ETH Zürich

ETH Zurich is one of the world’s leading universities specialising in science and technology. We are renowned for our excellent education, cutting-edge fundamental research and direct transfer of new knowledge into society. Over 30,000 people from more than 120 countries find our university to be a place that promotes independent thinking and an environment that inspires excellence. Located in the heart of Europe, yet forging connections all over the world, we work together to develop solutions for the global challenges of today and tomorrow.

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