Some plant species are 'fast'. These often found in resource-rich environments, where their strategy of fast resource acquisition and growth allows them to outcompete their more conservative neighbors. These same fast species often struggle in cold, arid or nutrient-poor environments in which 'slower and steadier' species are the winners, much like the tortoise eventually outcompetes the distracted hare in Aesop’s fable. But plants are not isolated in an ecosystem: they serve as primary resources for organisms both above- and belowground, which themselves eventually become the nutrients that plants feed on. What if these 'slow' and 'fast'strategies were not restricted to plants, but also extended to microorganisms, arthropods, or even larger vertebrates, meaning that whole ecosystems can also be ‘fast’ and ‘slow’?
We – a team of researchers then based at Senckenberg Biodiversity and Climate Research Center in Frankfurt, Germany - set out to test this idea. We focused on the 150 grasslands of the Biodiversity Exploratories, a large-scale project based in three regions of Germany, that, as a consequence of land use intensity differences, span a large gradient of disturbance and resource availability. We assumed that slow-fast strategy variation can be found within most functional groups, and hypothesized that these responses would be synchronized across the entire food chain from 'slow' strategies in undisturbed grasslands to 'fast' ones in heavily mowed and fertilized ones.
We soon encountered an unforeseen challenge. As vegetation ecologists, familiar with the well-established plant slow-fast spectrum and its well understood indicator traits (leaf nutrient content, specific leaf area, etc.), we delved into the literature to identify equivalent traits for the other taxa to test our hypothesis. Yet, we rapidly realized that most other taxa did not have such a well-established theory of functional strategy variation, which significantly complicated our task. We thus rallied a large team of colleagues of diverse expertise on each group of taxa we targeted and organized a series of small workshops. These were held online due to Covid-19 restrictions (a new thing at the time!) which allowed colleagues from not only Germany but also the UK, Netherlands and Switzerland to join. In each workshop, small teams of experts were tasked with identifying key traits that could describe a slow-fast gradient in their group and to draw clear hypotheses on how they might be related either to resource availability or disturbance. This collective synthesis effort, besides being highly stimulating and building welcome connections in lockdown times, allowed us to build a strong theoretical and meaningful foundation for our work. It was also the opportunity to learn more about international folklore, and the World’s many different versions of “The tortoise and the hare” fable involving hares but also frogs, elephants and whales competing against snails, hedgehogs and sea slugs!
The next step required matching the extensive abundance data from the Exploratories, which was available for many taxa from bacteria and protists to plants, arthropods and bats, to data for each of the traits identified by our experts. Fortunately, in the past years the availability of open trait data has rocketed for many groups, such as plants or arthropods, but data remained scarce for other groups – especially among micro-organisms. This sometimes required going back to the experts to find compromises between theory and the data that was available.
With time, Covid eased a bit and the core team were able to meet outside. Sitting in the grass on the banks of the river Main in Frankfurt, we pieced our first results together – and were thrilled to see it match, in the main, our expectations: slow-fast trait synchrony was present across multitrophic communities, and driven by both common responses of individual groups to land use intensity and indirect effects through trophic cascades. This gave us confidence to make the last step of the study, by incorporating ecosystem function data to show that 'fast' multitrophic communities also drive faster ecosystem functioning.
I take two lessons home from this journey. First, that work as a synthesis ecologist is meaningless without the unique involvement and expertise of colleagues and friends across disciplines and countries, who add substance, meaning and depth of insight to the patterns teased out of large datasets. Incorporating multiple knowledge sources and leveraging expert networks takes time, but is well worth it – it wasn’t a quick process, but like the tortoise maybe slow and steady can also win the race in science? Second, the results indicate the potential for new ways of thinking about communities and ecosystems; it might well be time to look not only at population- or community-level traits, but also to open the door to a 'whole-ecosystem' functional ecology, potentially describing a typology of ecosystem 'strategies' along environmental gradients, and at global scales.
Reference: Neyret, M., Le Provost, G., Boesing, A.L. et al. A slow-fast trait continuum at the whole community level in relation to land-use intensification. Nat Commun 15, 1251 (2024). https://doi.org/10.1038/s41467-024-45113-5