Terrestrial Ecology

Climate change and biodiversity loss are the two most pressing problems of the 21st century. The main objective of Terrestrial Ecology Group is to investigate how climate change and biodiversity loss affect the ecology of terrestrial organisms and ecosystem functioning. To achieve this broader objective, we study soil organisms and their interactions with grassland plants as our model system. We study climate change effects by studying the impacts of climate extremes, such as heat waves and extreme droughts by measuring the response and the recovery of soil organisms and plants, and how their interactions change during and after climate extremes.

News

Dr. Gerard Martinez-De Leon

Gerard successfully defended his PhD thesis on September 25th, 2024. He is our first “Dr. TERR”. Many congratulations!!

Heat extremes can increase ecological debts

In a new review paper published in Trends in Ecology and Evolution, Gerard Martínez-De León and Maddy Thakur from the Terrestrial Ecology division synthesise the main mechanisms mediating population and community responses to heat extremes, as well as their associated costs. Biological mechanisms immediately buffering the impacts of heat extremes can have lagged costs –known as ‘ecological debts’- that are likely to become more prevalent as populations or communities recover after extreme events. Gerard and Maddy propose a conceptual framework to infer how responses to heat extremes unveil over time, highlighting the roles of ecological debts in predicting population and community stability in a changing world.

Yu’s first PhD chapter is published

In a meta-analysis, we show that some of the major morphological root traits are negatively affected by drought intensity, particularly in trees, compared to other plant functional groups. Furthermore, our analysis also suggests that the longer duration of severe drought negatively affects the root traits of other plant functional groups like grasses and legumes. Published in BMC Ecology & Evolution, this meta-analysis is the first chapter of Yu Sun’s PhD thesis and was also done in collaboration with Prof. Christelle Robert from the Institute of Plant Science (IPS).

Shareen’s first PhD chapter out in Plant & Soil

Intraspecific plant competition can be crucial in determining how plant populations recover after extreme drought. In one of her PhD projects, Shareen shows that such competition constrains post-drought recovery in Centaurea jacea (a common meadow plant) but not in a range-expanding congener plant Centaurea stoebe. Moreover, arbuscular mycorrhizal fungi weaken the recovery of C. jacea. This project was co-led by Shareen and Ludo, and Micha participated in it as his BSc project.

Climate extremes and fungal-bacterial interactions

Climate extremes are likely to disrupt fungal-bacterial interactions, which are crucial for soil microbiome stability. In a recent Comment piece published in Nature Microbiology, Jingjing and Maddy discuss the importance of three kinds of inter-related biotic interactions between soil fungi and bacteria, and how they may change during and after climate extremes.

How will climate change alter the feeding biology of Collembola?

Collembolans are among the most diverse and important soil invertebrates for ecosystem functioning. Their feeding interactions with soil fungi are crucial for decomposing soil organic matter. In our recent perspective article, jointly led by Shareen and Gerard, we discuss how climate change will shift the feeding interactions between Collembola and fungi. We suggest that many collembolans may have to switch to low-quality mycorrhizal fungal diets due to a decline in their preferred saprotrophic fungal diets due to climate change.

Gerard’s first PhD chapter out in Oikos

Can we use trait responses to warming to explain population responses to extreme heat events? Yes!! Using life history and functional traits of four Collembola species distributed across different latitudes, we demonstrate how their population resistance is explained by survival, while their recovery after extreme heat is explained by fecundity response to warming.

Root exudates and rhizosphere microbiomes key for plant-soil feedback

In a paper published in Plant, Cell & Environment, we show that root exudate diversity and composition, along with rhizosphere microbial communities drive temporal changes in the strength of plant-soil feedback as plants grow. This experiment was performed with Holcus lanatus (a grass) and Jacobaea vulgaris (a forb).

Warming decrease Collembola biomass

In a recent experimental study, we show that geothermal warming can reduce the total biomass of Collembola. This study was performed in Iceland (see the experimental site in the image) and is published in Soil Biology & Biochemistry.

Global assessment of Collembola

In a recently published global analysis of Collembola, we show that the total estimated biomass of Collembola is 27.5 megaton Carbon, which is nearly three times higher than the total biomass of wild vertebrates. This study is published in Nature Communications.

INSECTS NEED OUR HELP IN A WARMING WORLD, NOW!

If no action is taken to better understand and reduce the impact of climate change on insects, we will drastically limit our chances of a sustainable future with healthy ecosystems.’ This warning in a very topical paper in Ecological Monographs comes from 70 scientists (including Maddy Thakur) from 19 countries around the world. But, they also provide ways to help insects in a warming world complete with management strategies.

New paper in PRSB

In a recently published meta-analysis in Proceedings of Royal Society B, Maddy and his colleagues show that interactive effects of warming and drought on plant biomass depend on plant life forms (woody vs. non-woody) and plant community composition (monocultures vs. polycultures).

Mycorrhizal association matters for plant’s responses to climate warming

In a paper published in Nature Communications, Maddy and his collaborators from East China Normal University show that terrestrial plants allocate more biomass to roots in warm and dry environments. In wetter environments, plants’ strategies are dictated by their mycorrhizal association. Plants associated with arbuscular mycorrhizal fungi do not have to allocate more biomass to roots in warmer and wetter conditions. Based on a global meta-analysis, these results provide important insights into factors that would alter terrestrial carbon dynamics in response to climate warming and precipitation variability.

How do organisms respond to, and recover after climate extremes?

In a recent review, Maddy and his co-authors present an extensive review of literature to show that most taxonomic groups living in terrestrial ecosystems are vulnerable to climate extremes, such as heat waves and prolong periods of drought. They further propose a conceptual framework to better integrate ecology of organisms to predict how they may recover after climate extremes have stopped.

New paper from a TERR research practical project

In a recent publication, we show that the relationship between the size of eggs and the number of eggs laid by Collembola varies in two different temperatures. Interestingly, egg size-egg number trade-offs were present in a colder temperature, but not in a warmer temperature, and also only in an asexual Collembola but not in a related sexual Collembola species. This work was carried out as one of our research practical projects in 2021, and was led by Arianne Marty.

Climate change and phenology: A new paper in Nature Climate Change

A new synthesis conducted by a group of international scientists including Madhav P. Thakur from the University of Bern reveals mismatches between above- and belowground plant phenology due to climate change. These findings are important to understand the consequences of climate change on terrestrial biodiversity.

Teacher of the year 2021

The biology students recently voted Maddy as the teacher of the year 2021. This award is organized by FS BIO at the University of Bern every year. Maddy was thrilled to be recognized by students, and is further motivated to make learning experience more fun for biology students. He is very grateful!

Soil microbial interactions and plant strategies

Together with colleagues from Wageningen University, Netherlands Institute of Ecology and Technical University of Munich, we explored how interactions within and between key microbial groups (bacteria, fungi and protist) alter plant's resource allocation strategies. Soil microbial interactions matter! But their effects vary if a plant is a grass or a forb or if they are early-successional or mid-successional

New Review Paper in Trends in Ecology and Evolution

Maddy along with his co-authors recently published a review paper in Trends in Ecology and Evolution on how temporal dynamics of plant diversity productivity relationships can be explained by changes in plant-soil feedbacks.

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