Liesje Mommer‘s research focuses on  “belowground plant-plant interactions” within the Plant Ecology and Nature Conservation group of Wageningen University, the Netherlands.

Recently, the theme of her research has expanded to include plant-fungal interactions, as root-root interactions cannot be understood without considering the myriad of microbes in the soil. To reveal these ‘hidden’ interactions and the consequences for ecosystem functioning, she combines insights from plant ecology, molecular biology, soil chemistry and phytopathology. Liesje designed her own postdoc projects in the Netherlands (Wageningen and Nijmegen), and has traveled the world to supervise projects in Germany, China and Russia.

Liesje is a principal investigator in The Jena Experiment, looking at the role of root-root interactions as drivers of the positive interactions between biodiversity and ecosystem functions in natural grassland vegetation. Currently, she is aiming to translate the ecological insights from these biodiversity experiments in order to diversify agricultural ecosystems.

How I became an Ecologist

As a child, I remember picking all kinds of flowers during the weekly walks with my parents. Rather than putting the flowers in a vase, I preserved them in my own little herbarium. Although I was fascinated by the beauty and diversity of plants, I was not then thinking of becoming an ecologist. Instead, I wanted to ‘save the world’ and to work on one of the biggest challenges mankind is facing: feeding the increasing world population.

I decided to study biology at Wageningen University in the Netherlands, originally an agricultural university, which allowed me to combine the traditional biology curriculum with agricultural courses in soil science and crop modelling. For example, I extended a computer model predicting cocoa production in West-Africa with a root growth module. One of the most inspirational moments was a lecture series about tropical farming systems by Prof. Louise Fresco. She became my role model, not in relation to doing science for gathering knowledge per se, but for doing science to make an impact; in her case in agricultural systems. Her TED talk in 2009 summarises the main lessons that I took from her lectures: “Food is as important as energy,…, as the environment, all is interlinked”.

I then performed a research project in Switzerland, exploring the potential of intercropping leek and celery to reduce the pest pressure of thrips. I was so excited when we discovered that these interspecific plant-plant interactions helped to reduce thrips infestations in leek. It appeared that science – ecological interactions – could change the world or, at least, change agricultural farming practices! I was in the right place, but unfortunately, it was not at the right time. Pesticide use was still common and although machinery had been developed to harvest the crops separately, few farmers were persuaded to consider intercropping as an alternative to monocultures with high inputs of pesticides and fertilizers.

The disappointment I felt then inspired me to follow a different path. I would work on plant ecology first, expanding my knowledge of plant physiology and plant-environment interactions, and maybe return to agriculture when the time was right. I focused on projects with the freedom to develop new methods and concepts. I did a PhD on the acclimation responses of plants when submerged, developed molecular tools to determine species-specific root biomass in plant mixtures as a postdoc, and I am currently collaborating with phytopathologists to reveal the interplay between plants and pathogenic fungi and its role in plant diversity-ecosystem functioning relationships. The path wasn’t always easy to follow – rejected papers, exciting research proposals not funded, two children that brought a lot of joy, but also sleepless nights – but I followed my heart, gained experience and self-confidence, met many nice, committed and smart scientists across the globe. I learned a lot.

Maybe I was not saving the world, but I did keep the words of Lao Tzu in mind: “The journey of a thousand miles begins with one step”. Now, I feel the time is right to return to agriculture, as the passion to change the world still smoulders within me. Bridging the gap between natural and agricultural sciences. As a professor, I collaborate with farmers to integrate ecological principles in future farming systems. Ultimately, the goal is still to feed the increasing world population in a changing world, in a sustainable way. I think that is what I can contribute as an ecologist: understanding the complexity of ecosystems and integrating ecological insights from nature into modern and sustainable agricultural practices.

Liesje Mommer, Associate Editor of Journal of Ecology

Read more of our editor’s Ecological Inspirations on the journal blog.