Gradual and abrupt environmental change: connecting physiology, evolution and community composition

Project Information

Gradual_Change

Grant agreement ID: 694368

DOI

10.3030/694368

Project closed

EC signature date 6 June 2016

Start date 1 October 2016

End date 30 September 2023

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 2 390 598,00

EU contribution

€ 2 390 598,00

Coordinated by

FREIE UNIVERSITAET BERLIN
Germany

Periodic Reporting for period 5 - Gradual_Change (Gradual and abrupt environmental change: connecting physiology, evolution and community composition)

Reporting period: 2022-12-01 to 2023-09-30

Summary of the context and overall objectives of the project

A major goal in ecology is to understand and predict how environmental change, including drivers of global change, affect communities and ecosystem functioning, with society demanding answers to these pressing questions. A key limitation of virtually all experimental approaches addressing such questions is that treatments are delivered abruptly, while many changes occurring in nature are gradual. Another major limitation addressed in this project is that we do not understand the concurrent action of many drivers acting at the same time. Finally, another large unknown concerns the actual factors of global change: are we still discovering new drivers?

The overall objective of this project was to make decisive progress in experimental work addressing these questions, with a focus on soils and soil biodiversity (in particular, fungi).

There are three major conclusions and findings: (1) In many cases it makes a difference if factors are applied suddenly (abrupt) or more gradually; that is, the rate of change matters. Effects can be either under- or overestimated in the typical sudden-on experimental approach. (2) We defined and carried out pioneering work on an emerging new factor of global change, microplastic (meeting with large interest from the public). We found that microplastic affects various soil properties and processes, as well as ecosystem functioning and plant and microbial community composition, highlighting the potential for feedbacks within the Earth system. Microplastics are a new type of pollutant, many effects of which can be understood only by taking into account the particle nature of microplastics (for example, the shape is very important). (3) We have pioneered the experimental study of multiple factors of global change (up to 10 concurrent drivers), using a novel experimental design (randomly sampling from a pool of factors). Using this approach, we could discover surprises when many factors are acting on soils that could not be predicted from the individual factor effects, and we found that the sheer number of factors acting on a soil (or ecosystem) can alone explain key aspects of the outcome. We also find the signature of the number of factors in global observational data, and have set up a field experiment to further test these ideas.
Especially the multiple factor work is highly relevant for understanding the nature of global change, and adds a new tool to the portfolio of experimental work in this field and beyond. The result that the number of factors alone has an effect also has important consequences for policy, for example for environmental impact testing and regulations. The same experimental design can also be used to address a wide range of other questions in ecology, and likely in other fields.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

This project has yielded over 80 peer-reviewed publications, including several in top journals. The PI has actively disseminated results via social media (>13K followers on X/ Twitter; and many other platforms, including LinkedIn, mastodon, bluesky and instagram), in many invited talks, and in interaction with artists (several exhibits, 2 film productions, one music piece composed based on data from one of our key papers).

We have performed a range of experiments comparing gradual and abrupt change in environmental factors. In one notable case, the gradual change had greater effects than the abrupt change, contrary to what is mostly found. In a major conceptual advance, we have integrated >60 concepts with a temporal component in ecology, placing them in a common framework. This framework is a nested hierarchical framework recognizing several levels of complexity (from single events, to multiple events to trajectory), and serves to unify temporal ecology. This work places the abrupt vs. gradual focus of the project into a broader context.

We have established microplastic as a factor in global change biology, by providing a keystone review paper, many conceptual advances, and several pioneering papers describing experimental results on soil and soil ecosystems. These results have been widely disseminated, and have been met with a lot of interest from the media (print, radio, podcast and several times of German national and regional TV) and the public. In addition to many laboratory and greenhouse experiments, we have also made conceptual advances, including the appreciation of microplastic as a pollutant where the shape and interior volume (releasing additives) is important for understanding effects (leading to the concept of the global toxicity debt of microplastic). Work recently culminated in a review paper in Nature Reviews Microbiology on the plastisphere, summarizing much of the work on this new ecosystem compartment.

We additionally set up up and successfully completed a first complex and unprecedented experiment to examine the multi-factorial effects of global change on soil properties and functions, with a focus on fungi. The results suggest that effects of an increasing number of global change factors eventually become unpredictable from single-factor responses, and harbor ecological surprises. The design we pioneered for this lab experiment (random sampling from a pool of factors) has now been used in many additional experiments, and also in the field: the Berlin Global Change Experiment is still ongoing. This experimental work has also been accompanied by several conceptual advances, mainly related to factor classification (including the first trait-based classification for global change drivers), and most recently, insights into at what levels of the ecological hierarchy different factors enter. We also found the signature of the number of factors in a global obsevational study.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Work conducted in our project, both experimental and conceptual in nature, has highlighted the importance of considering the rate of change in studies of global change, an aspect that has been mostly ignored. Interestingly, effects can be both over- or underestimated when using the typical sudden-on approach.

Our project has decisively contributed to understanding the effects of microplastic on soils and terrestrial ecosystems, and helped initiate a global research focus on microplastic in soils. We have established microplastic as a factor of global change and highlighted its unique features. Much work by others has built on the initial research conducted in this project, and microplastic research is now a global endeavor, while, at the beginning of the project, microplastic in soils and terrestrial systems was not a research topic broadly pursued.

Experiments and conceptual developments on the concurrent action of numerous factors of global change have led to a breakthrough in our understanding of global change effects: the number of factors alone can explain a substantial proportion of some effects. This experimental design (random sampling from a pool of factors), developed in this project, is likely to be adopted more widely and also beyond global change biology or even ecology. Much of our recent work in the project has built on the analogy of global change factors with species in a plant community, and this transfer of ideas is the nucleus for additional innovation and experimentation currently ongoing.

In all three areas outlined above, the project has significantly pushed progress beyond the state of the art.

View of an experiment in which global change effects on soil are tested