Throughout April, we are featuring the articles shortlisted for the 2021 Harper Prize. The Harper Prize is an annual award for the best early career research paper published in Journal of Ecology.

Dina in ‘t Zandt et al.’s article ‘Species abundance fluctuations over 31 years are associated with plant–soil feedback in a species-rich mountain meadow‘ was one of those shortlisted for the award.

⭐️About me

I grew up in the Netherlands, football in one hand, violin in the other, and climbing as high as I dared in my favourite tree in the local forest. I always felt drawn to nature, forests and mountains in particular, but never realised it could be my profession. My first encounter with ecology was quite accidental, and occurred via various ecology-related courses during (what I thought was going to be) a BSc in medical biology at Radboud University, Nijmegen, the Netherlands. The world and community that opened-up for me has kept amazing and challenging me until this day. I specialised in plant ecophysiology in my thesis projects at Radboud University and ETH Zurich, Switzerland. After my MSc, I worked on plant-soil-microbiota interactions in catch crop systems in the group of Florian Wichern at the Rhine-Waal University of Applied Sciences, Kleve, Germany. I returned to Radboud University for a PhD in the group of Hans de Kroon to study the role of plant-soil feedback as a driver of plant species co-existence. After my PhD, I did a postdoc in Michael Bahn’s group at the University of Innsbruck, Austria, working on long-term recurrent drought and seasonal asynchrony in mountain grasslands. Currently, I am a postdoc in Zuzana Münzbergová’s group at the Czech Academy of Sciences, Průhonice. One of my lines of research focusses on how microbial networks in soil, plant rhizospheres and roots are shaped by plant community stability, plant species competition and soil legacies. My second line of research targets the effects of temperature, precipitation and long-term recurrent drought on plant-soil-microbiota interactions. I currently live in Ireland, hosted in Fiona Brennan’s group at Teagasc, Johnstown Castle.

🔎The story behind the paper

Before I was a twinkle in my parent’s eyes, Tomaš Herben and colleagues were already out in the field, establishing four permanent plots in 1985 in a 300-400 year old species-rich mountain meadow in the Krkonoše mountains, Czech Republic. Their persistence resulted in a unique dataset containing 31 years of plant species abundance patterns in space and time. In the Radboud University greenhouse, we combined this exceptional dataset with a two-phase plant-soil feedback experiment including 24 of the plant species from the mountain meadow. It was the first experimental work of my PhD and I was at a loss on where exactly to start. However, luck was on my side when an enthusiastic MSc. student popped-up wanting to join (second author Annelien). The experimental work was up and running, and the greenhouse staff were condemned to hours and hours of 90s music.

The publication itself started as a humble supplementary figure (Fig S7) in another chapter of my thesis (https://hdl.handle.net/2066/221712). It was not until I sat down with Tomaš for 3 days to have a go at some more in depth data analyses that I realised how creative data analyses can be. As a result of these newly discovered possibilities in combination with the freedom and support I was given to follow my ideas and hunches, the supplementary figure grew so large it became its own manuscript. Many hours of brain crunching were required before the story finally came together and was accepted for publication in Journal of Ecology. This publication stands out because of the exceptionally long time frame it covers and the novel insights it brings to the field of plant-soil feedback. For me, the publication also embodies the journey of my PhD, from being motivated by experimental work, to discovering the possibilities and creativity in data analysis and scientific writing. These discoveries and freedom to pursue my ideas paved the way to my current research lines and position in which I continue chasing previous and new ideas while focussing almost completely on data analysis and writing.

🌿About the research

Plant communities are assembled of plant species differing in how successful they are in the particular environmental conditions of the system. For species-rich grasslands, this raises the question why the most successful plant species do not outcompete the less successful ones, creating low diverse assemblages. The hypothesis is that interactions between plants, soil and microbiota result in species-specific and density-dependent effects on plant growth: plant species growth is hampered at times when the plant species is at a high abundance, but negative effects cease at times when the plant species’ abundance is low. We tested this hypothesis by combining a 31 year long plant abundance dataset from the field with a plant-soil feedback dataset from the greenhouse. Plant-soil feedback was defined as the difference in growth of a plant species on soil where the same plant species had grown before compared to growth on a mixture of soils of all used 24 plant species.

Approximately 50% of the species showed to be negatively affected by their own species’ soil. The relationship between a species’ plant-soil feedback and field abundance fluctuated over time, but plant species with a negative plant-soil feedback were overall more abundant. We furthermore detected a significant coupling in the abundance fluctuations of negative and positive plant-soil feedback species: at times when negative plant-soil feedback species increased, positive plant-soil feedback species decreased and vice versa. This coupling was likely driven by years in which manuring took place. In a conceptual figure, we reconciled these complex relations. We suggest that in years with manuring, the stronger plant competitors increase in abundance, which reduces abundance of subordinate species. The following years without manuring, the stronger plant competitors with higher abundance are hampered by negative plant-soil feedback, decreasing their abundance. This creates critical opportunities for subordinate competitors (positive plant-soil feedback species) to recover and increase in abundance again. We present novel dynamics on the ways that plant-soil feedback, soil nutrient availability and species’ competitive abilities operate in concert to drive species co-existence and ultimately diversity.

Find Dina on Twitter and Google Scholar.

Read the full list of articles shortlisted for the 2021 Harper Prize here.