Featured

Our community ecology group at University of Bern (led by Eric Allan) works on two interlinked questions: what maintains diversity within plant communities? And what effects do changes in community diversity have on the functioning of ecosystems and the services they provide?
We try to understand the biodiversity of plant communities from several different angles and we do experiments in the field and greenhouse and use statistical modelling to test these questions in large datasets.
On our website you can find more information on the major projects we are involved in, together with updates on our activities and interests.

The PaNDiv experiment in the media

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!

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)

 

PaNDiv cake 1

The amazing PaNDiv cake by @debi.schaefer

British Ecological Society Conference 2019

This year’s British ecological society (BES) conference was the largest ever hosted (not counting the joint meetings with other societies), with more than 1200 participants. This large number was reflected in many parallel sessions and topics, ranging from microbial ecology to macroecology and biogeography, from very specific species interactions to whole ecosystems and from theoretical or computational ecology to very applied conservation and restoration ecology. There was plenty of food for thought for everyone’s taste, but at times it was difficult to keep the overview. Fortunately, the plenary lectures helped keeping things a little bit more general, by discussing important issues in ecology, for example communicating research, contextualizing, i.e. explicitly mentioning scales for biodiversity studies and considering in parallel above-ground and below-ground communities.

I must say, I really enjoyed the whole conference. There were so many great contributions by great scientists. Personally, I really liked the talks of Alexandra Wright, James Buckley and Kimberley Simpson, who spoke about the effects of living plant diversity on the microclimate, herbivore pressure and plant defense along an environmental gradient and growth-strategies respectively. – Seraina

It was great to meet ecologists working on different topics like marine ecology, or theoretical ecology. I could discuss with many people and had some really relevant insights for my project. There were many great talks, and it’s difficult to choose, but I think my favorites were the presentations of  Ian Donohue on ecosystems stability, Jakob Assmann on remote sensing of the Greenland flora and  Korinna Allhoff on competition in seabeds. – Caroline

I am feeling particularly inspired after this conference, especially to explore energy fluxes in grasslands thanks to Andrew Barnes and to link metabolite variation to growth defence trade-offs thanks to a great talk by Tom Walker. I’m looking forward to the BES conference next year already! – Tosca  

It had been some years since I last attended a BES Meeting but I enjoyed every moment there. I met all friends and I made new ones that hopefully will lead to some sort of collaboration in the future. I really enjoyed plenary talks by Jonathan Chase and Esther Ngumbi, truly inspiring for ecologists in any stage. I also liked the presentation by Korinna Allhoff about Bryozoa coexistence and Ainhoa Magrach’s adventures pursuing hummingbirds. Finally, I must say that lab members dancing skills are on point! – Hugo S.

The BES 2019 has been a fantastic event to reconnect with some of my favorite Soil Ecologists working on soil organisms and the ecosystem processes they drive; with no specific order Nicolas Fanin, Ciska Veen, Paul Kardol, Karina Clemmensen and Franciska De Vries. I also think that the BES meeting was great to know better my colleagues as we went there as a group! Overall, it was a good place to make stronger bounds between us and plant seeds for future research projects! – Nadia

The Allan group contributed three posters and four talks to the conference in different sessions. Tosca, Thu Zar and Caroline showed posters about primary results and planned analysis about collembola, plant-herbivore interactions and plant species coexistence in the PaNDiv experiment. Anne presented her work about top-down and bottom-up regulation of herbivores in David Wardles island study system. Nadia talked about how saprotrophic and mycorrhizal fungi decompose litter in the face of nutrient deposition. Hugo used the large data sets of the biodiversity exploratory to show that there are two main thresholds of land use intensity (one for taxa and one for functions), which once crossed cause rapid ecological changes and likely hysteric behavior. And Seraina showed that even though diversity causes comparable patterns in different ecosystem functions, different species contributed to these patterns and likely also different mechanisms.

Poster

Tosca, Caroline and Thu Zar

Talks

Hugo, Seraina, Nadia and Anne

The many social activities throughout the conference promoted a relaxed and friendly atmosphere and gave the conference a touch of “school camp” for grown-ups to meet old and new friends. We drank wine and chatted at the welcome mixer, discussed about work-life balance in a workshop and danced ceilidh folk dances at the conference dinner. Overall, the conference was very inspiring, and we all came home with a pile of notes and lists of soon-to-be-out studies we must read. We are definitely looking forward to the 2020 meeting in Edinburgh!

Virtual_Reality

Thu Zar, Eric, Seraina, Anne and Tosca

Mushroom picking

Autumn time is mushroom time so on 18th of October 2019 the Allan Lab went on a mushroom-picking adventure in the Bremgartenwald near Bern. We were amazed by how many different species we saw and we even found a huge amount of edible ones – many Xerocomellus (Rotfussröhrlinge), some Boletus badius (Maronen-Röhrlinge), some Cantharellus (Eierschwämme), various puffball species and a few Suillus grevillei (Goldröhrling)!

We also visited the famous “Glasbrunnen” and in the evening we enjoyed a delicious meal and wine together at Provisorium 46.

This slideshow requires JavaScript.

New preprint about sick plants in grassland communities

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)

Picture1

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

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 :

 

Group hike

On the 24th of June 2019 the Allan Lab made an excursion to the mountains in the Kandertal region.
We started in the morning from Bern by train and after changing to the “postbus” in Reichenbach we took the “chairlift” up to Ramslauenen. We hiked around the top and after a picnic followed a path back to Kiental. Despite the heat and the steep slopes, we enjoyed the blue sky, the fantastic panorama, the alpine flora and each other’s company.
We also used this opportunity to learn something about the vegetation – Debi showed us many species and explained to us their special characteristics and habitat.

This slideshow requires JavaScript.

First results of PaNDiv on preprint

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.