prof.dr.ir. L (Liesje) Mommer

Leading for biodiversity

By working as a plant ecologist in biodiversity research for many years, I had learned that biodiversity matters. Biodiversity improves ecosystem functioning. Species-rich plant communities perform better and are more resilient to climate extremes and pathogen outbreaks than species-poor ones. 

Still, I was terribly shocked when reading the IPBES report (2019) reporting the devastating scale and rate of biodiversity loss globally. The biodiversity crisis is unprecedented and our human activities are at risk. Time to step up for biodiversity. Only if we start working together - now - in an integrated way, we are able to bend the curve of biodiversity loss (www.wur.nl/bendingthecurve). Therefore, I initiated and lead the Wageningen Biodiversity Initiative, which is a network of scientists and stakeholders that works on developing and implementing nature-inclusive solutions in the food system, landscapes and societies.   

November 2022: Third time in a row: Highly cited scientist!

Each year, Clarivate™ identifies the world’s most influential researchers - the select few who have been most frequently cited by their peers over the last decade. In 2022, fewer than 7,000, or about 0.1%, of the world's researchers have earned this exclusive distinction.

I am so proud to announce that my work is (again! also the two years before) considered for this exceptional research influence, demonstrated by the production of 15 highly-cited papers that rank in the top 1% (and of these 2 are even 'hotly' (0.1%) best cited papers in the Web of Science™. I am one of the four women of WUR to receive this award. And - and a milestone: my 100st paper came out! Thanks to all my WUR, national and international collegues with whom I am working 'underground' to understand the world around us! It is a great encouragment to keep digging! https://clarivate.com/highly-cited-researchers/

October 18th 2022: PhD defense Eline Ampt

Biodiversity can reduce or increase disease transmission. These divergent effects suggest that community composition rather than diversity per se determines disease transmission. In natural plant communities, little is known about the functional roles of neighbouring plant species in belowground disease transmission. 

In her PhD thesis, Eline focussed on  the belowground interactions of a plant community and a unbiquitous pathogenic actor:  the soil-borne fungus Rhizoctonia solani. Eline investigated the transmission of this pathogen on community composition. Neighbouring plants either reduced or increased disease transmission in host plants. Her work shows that neighbour-induced shifts in the importance of these mechanisms across root networks either make or break disease transmission chains. Some neighbours are nice, others you better avoid. Plants are just like people ;)

Understanding how diversity affects disease transmission requires integrating interactions between host, neighbouring species and their pathogens in a given environmental setting. Future work will need to reveal what plant traits and interactions with other soil microbes affect this biodiversity-disease relationship.

Three papers have been publised already, in European Journal of Plant Pathology, New Phytologist and Journal of Ecology. The fourth is underway! 

Research focus: The collaborative role of root traits in ecosystem functioning 

Plant roots perform multiple functions, including plant anchorage and belowground resource uptake, especially nitrogen, phosphorus and water. They have evolved a wide range of root traits to simultaneously perform these functions, which respond to spatial and temporal changes in soil properties and resource availabilities. Variation in root traits also implies large impacts on soil and ecosystem functions. However, despite the exponential interest towards root ecology, the connections of root traits to plant and ecosystem functioning remain poorly understood.

Because of this knowledge gap in ecology, I have - together with prof. dr. Alex Weigelt from University of Leipzig, Germany - initiated and led the international sROOT and RootFun workgroups. We have been enjoying working together - online and in person - in a series of collaborative efforts to understand root trait vatiation in whole-plant and ecosystem contexts.

We demonstrated that root trait data from 1810 species across the globe confirm a classical fast-slow “conservation” gradient as frequently found for leaves. Importantly, however, we showed that most variation is explained by an orthogonal “collaboration” gradient, ranging from “do-it-yourself” resource uptake to “outsourcing” of resource uptake to mycorrhizal fungi. Plants thus show us that things have not to be done alone, but that 'doing things together' can be a succesful strategy in life! This broadened “root economics space” provides a solid foundation for predictive understanding of belowground responses to changing environmental conditions.

Do you want to work with root traits yourself? Check out the GRoot root database! We made root trait data accessible for non-experts.

Are you interested in our findings? Check out our high-impact papers:  Bergmann et al 2020 Science Advances; Laughlin, Mommer et al, 2021 Nature Ecol Evol; Weigelt, Mommer et al 2021 New Phytologists, and more in the pipeline! 

Picture: Artwork by (C)Colleen Iversen showing the spirit of sROOT: Collaborate! Image of the turtles are  inspired by the game Dodelido, as playing games was a fun and connecting asset of the working group.

Translating ecological knowledge for agriculture I: Cover crops 

Cover crops are planted to maintain and improve the quality of probably the most precious asset in agriculture: healthy soils. These crops are currently widely applied to improve soil structure and prevent nutrient leaching. Next to these abiotic goals, cover crops have a major potential to lower the soil-borne disease pressure. The latter is a pressing issue as numerous pesticides that have been applied for decades to manage soil pathogens were banned recently. Particularly for the management of plant-parasitic nematodes and pathogenic fungi there is an urgent need for alternative measures, which may be provided by cover crops suppressing pathogens directly or indirectly via the stimulation of antagonists. However, the presence of multiple soil-borne diseases is commonplace, and a poorly-informed cover crop choice may even result in unintentional accumulation of one of these pathogens. Collaborating with Sara Cazzaniga, Hans Helder and Joeke Postma and stakeholders we will provide a scientific basis for optimal cover crop combinations that suppress pathogens and boost soil biodiversity. 

Translating ecological knowledge for agriculture II: the transdisciplinary NWA project CropMix goes belowground!

New project about to start! Read more about the transdisciplinary approach in Cropmix. Within this framework, I co-lead two belowground workpackages: 

A diverse team with 2PhD students, Gerlinde De Deyn, Jasper van Ruijven and Marie Zwetsloot will identify how crop diversity in space (e.g. strip cropping) and time (e.g. rotation) affects two important belowground processes: nutrient cycling, including decomposition and use efficiency of different nutrient sources (Project A) and the risk of soil-borne disease outbreaks (Project B). The aim of the projects is to find crop combinations and belowground plant traits that are beneficial for nutrient cycling and soil-borne disease suppression. These PhD projects will contribute to understanding soil functional biodiversity through interactive relationships with nutrient cycling, soil-borne pathogens and mutualists.

November 2022: Meeting Merlin Sheldrake - Lessons from fungi for leading change 

In 2022 Merlin Sheldrake was awarded the Groeneveldprijs for his incredibly beautiful book about the fungal world 'Entangled Life'. I was offered the honor to deliver the Groeneveld lecture. I spoke about how working with soil-borne fungi has changed my way of being and leading for change. Read the whole lecture here.

The beautiful mycelium on the slide is excellent artwork created by Suzette Bousema.

Playing hide and seek: the VIDI project

In 2015, I was awarded a personal NWO-VIDI Innovational Research grant to reveal the interplay between soil-borne pathogenic fungi, conspecific and heterospecific grassland plants in order to reveal the role of soil-borne pathogens in regulating the positive biodiversity effects and maintenance of coexistence. Together with the VIDI team members,- Eline Ampt, Sofia Fernandes Gomes, Jose Macia Vicente (and in the past also Davide Francioli),  I aim to reveal the functional interactions of the main soi-borne fungal pathogens driving the biodiversity effect in grasslands. My team and I perform 1) community assembly studies with both fungal and plant communities in order to test host-specificity 2) focus-expansion experiments with plant monocultures and mixtures to study density-dependence and neighbour effects. The insights obtained from these controlled experiments will be tested at larger spatial scales and over longer time scales, in more natural settings. 

To reveal these ‘hidden’ interactions and the consequences for ecosystem functioning, I and my team integrates insights from plant ecology, molecular biology, soil chemistry and phytopathology. My mission is to translate the ecological insights from these biodiversity experiments to diversify agricultural ecosystems, as I described in this blog https://jecologyblog.com/2018/03/05/liesje-mommer/.