Category Archives: PaNDiv

The PaNDiv experiment in the media

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The PaNDiv experiment has been featured on the radio twice recently.
Noémie Pichon spoke about the experiment and her recently published work on decomposition on the Swiss French radio station RTS. Listen to the interview (in French) here.
And Seraina Cappelli gave an interview on the experiment and her recently published work on foliar pathogens for the Swiss German radio station SRF. Listen to the interview (in Swiss German) here.

The experiment was also featured in the “Berner Zeitung”, read the report on the experiment and first published results here (in German).

The first two PaNDiv-ers successfully emerged!

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On the 21st of January in 2020, the first two PhD students of the PaNDiv project successfully defended their PhD.

Congratulations to Dr. Pichon and Dr. Cappelli!

Noémie investigated the effect of nitrogen enrichment and found that the direct and indirect effects of nitrogen enrichment were of similar importance in affecting ecosystem functioning. She found that species richness increased multifunctionality, as did functional diversity, while added nitrogen dampened these positive effects. The most functionally diverse communities were even slightly better at providing multiple functions than the low diversity fertilized communities. This suggests that managing for diversity can not only increase in productivity, but also provide multiple benefits compared to intensive systems. bioRχiv publication, Functional Ecology article, Functional Ecology blogpost

Seraina looked at the effect of removing plant pathogens (by applying fungicide) and found support for the growth-defense trade-off hypothesis, which states that fast growing species are less defended. Growth strategy (specific leaf area) was the main driver of infection. Surprisingly, there was no direct effect of nitrogen enrichment on fungal infection. She also found consistent negative selection effects and neutral to positive complementarity effects for all functions. The mechanisms underlying the diversity effects varied between the functions highlighting the importance of a high species diversity for the maintenance of multiple ecosystem functions. bioRχiv publication

The PaNDiv project now goes into its second phase and continues to explore new and exciting questions about the direct and indirect effects of global change drivers on above- and belowground invertebrate, fungal and plant communities and functioning.

Dr PichonDr. Pichon
with Prof. Matthias Erb (chair), Prof. Jasper van Ruijven (external examiner) and Prof. Eric Allan (supervisor)

 

Dr CappelliDr. Cappelli
with Prof. Matthias Erb (chair), Prof. Jasmin Joshi (external examiner) and Prof. Eric Allan (supervisor)

 

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The amazing PaNDiv cake by @debi.schaefer

New preprint about sick plants in grassland communities

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Slowly but steadily the results of the PaNDiv experiment start to be available. With many helping hands we piled up data about fungal infection, plant traits, community composition, biomass etc. and are now putting the pieces of the puzzle together. In the latest preprint we show that the functional composition of a plant community is a main driver of fungal infection and that the consequences of fungal infection are context dependent.

Sick plants in grassland communities, Cappelli et al. 2019 (preprint)

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Figure 1 Overview over the main hypotheses which we tested. Growth-defense trade-off hypothesis: Plant species adapted to resource-rich environments and able to compete well under nutrient rich conditions are often less defended against natural enemies. Nitrogen disease hypothesis: Higher nutrient content of the plant material following nitrogen fertilization should promote disease. Host dilution hypothesis: Many pathogens are dependent on the availability and density of host plants. At high plant diversity the abundance of each host plant is in average lower than in species poor communities, which is suggested to be the underlying mechanism of observed negative diversity-disease relationships.

 

3rd Wild Plant Pathosystems Conference

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I (Seraina) am just back from the 3rd Wild Plant sick_ToPathosystems Conference in Frankfurt, which was all about “sick plants in the wild”. It was a very small meeting with excellent presentations of amazing scientists, a museum tour, wine tasting and walks in the forests. I was honoured to present my fungal pathogen results from the PaNDiv experiment and get the chance to talk to many interesting people, working with a wide variety of pathosystems. I learned a lot about viruses and fungal pathogens and their vectors, about the possibility to identify different Uromyces species based on their smell, about the pathogen communities on different plant species and much much more.

Conference impressions on twitter #wpp3 :

 

First results of PaNDiv on preprint

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IMG_20171003_140655623After 840 litter bags sewed, 2.5 months of decomposition, 4 years of experiment running and more than a 100 helpers helping, we are happy to announce that we submitted last week the first results of the PaNDiv Experiment. This paper looks at the response of decomposition to direct and indirect effects of nitrogen enrichment, with a fancy structural equation model testing the relative importance of litter quality and soil biotic and abiotic conditions.

It highlights the importance of a plant community functional shift under nitrogen enrichment. And for those that can’t wait until the paper gets accepted, here is the submitted draft on bioRxiv:

Decomposition disentangled, Pichon et al. 2019 (preprint)

Final results of the structural equation model, showing effects of nitrogen enrichment, plant species richness and plant functional composition on decomposition. Dashed arrows show negative, full arrows positive path coefficients. The arrow size is proportional to the path coefficient. Double-headed grey arrows show covariances.

 

BES Annual Meeting 2018

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The best thing about Christmas is the BES Annual Meeting. Some of the lab members – Seraina, Eric and Noémie – attended the venue in Birmingham and had the chance to follow an extraordinary selection of talks and posters. Among others, we saw a great session about long-term experiments, what has been done and what is to do next (Andy Hector, Alexandra Weigelt and others). To the question “are you also part of a long term experiment?”, we are now answering: “we just started one”. We also saw presentations about phylogenetic and functional traits linked to multifunctionality (Y. Le Bagousse-Pinguet), upscaling BEF experiments results to landscape diversity (G. Le Provost), a great citizen science project looking at herbivory drivers on oaks (E. Valdés-Correcher) and my personal favourite, tracing C and N flows in grassland plants and soil food webs (M. Chomel).

A whole wall was covered in drawings due to the Journal of Applied Ecology brilliant suggestion to “draw your study organism” (see Seraina’s work of art, #PaNDiv), and we could even play cards with the Catastrophic game supporting systems thinking (P. Holland).

Let’s not forget the great poster about sick plants in grassland communities (S. Cappelli) and a presentation disentangling nitrogen direct and indirect effects on decomposition (N. Pichon).

What a nice and motivating end to 2018 and look forward to 2019!

NP & SC

 

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Study organism drawings

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The vegetative traits are for sure right

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Noémie and the decomposition

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Another highlight of the conference: Phil Grime in front of his poster

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Seraina and sick plants

Fieldwork season wrap up

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The sheep are now back next to the PaNDiv field site, which means two things: winter is coming, and after a season outside the fieldwork is over!

Maintaining the experiment has already kept us quite busy over the last months: weeding three times the whole field to always have the same diversity in the plots, spraying fungicide for the pathogen exclusion treatment and fertilizing to study the effects of Nitrogen addition.

On top of that, we harvested this year again a lot of data. For all our species, we quantified fungal pathogen infection, looked at herbivory damage and measured classic functional traits (height, SLA, LDMC, etc). We assessed the percentage cover of all plant species growing on the field, and collected over 3000 biomass samples and 30 000 insects. This year we had a closer look at the belowground compartment, measuring soil respiration regularly and collecting more than 1000 soil samples.

We also welcomed researchers from other universities to collaborate on the PaNDiv project. Rodrigo Granjel (1), PhD student from Sevilla, Spain collected data to study coexistence mechanisms. Bjarke Madsen and Urs Treier (2) from Aarhus, Denmark, flew their drones over the field, to link ground measurements with remote sensing data.

In our greenhouses facility, we grew the 20 PaNDiv species and the most common weeds invading the plots with an N addition treatment, to get an array of functional traits in controlled conditions. We also used this opportunity to explore the variability and the response of morphological traits, for instance related to vegetative propagation, together with Mathieu Millan, a researcher in plant architecture from Montpellier, France

We couldn’t do that much without a dedicated team of PhD, Master students and technicians, and all our hard working field helpers. More than 50 different people came to work with us between April and November, thank you!

Now it’s time to process all these samples, analyse the data … and get ready for next fieldwork season!

(1) http://www.oscargodoy.com/
(2) https://twitter.com/UAS4Ecology

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March, a cold start of the fieldwork season

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In June the plants have grown big

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Spraying fungicide to study the effects of pathogen removal

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July, second weeding of the whole field

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Biomass cutting (photo Beatrice Schranz)

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Collecting insects with suction sampling

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Graphosoma italicum, one of the many insects found on the field (photo Tosca Mannall)

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Autumn soil sampling