A spatially explicit trait‐based approach uncovers changes in assembly processes under warming

• Published in: Ecology letters 2023-07, Vol.26 (7), p.1119-1131
• Main Authors: Bektaş, Billur, Thuiller, Wilfried, Renaud, Julien, Guéguen, Maya, Calderón‐Sanou, Irene, Valay, Jean‐Gabriel, Colace, Marie‐Pascale, Münkemüller, Tamara
• Format: Article
• Language: English
• Subjects: Assembly; Bioclimatology; Botanics; Climate change; community assembly; Competition; Ecology, environment; Environmental changes; environmental filtering; Filtration; Global warming; hierarchical competition; Life Sciences; Plant communities; Plant populations; reciprocal transplant; spatial associations; symmetric competition; Vegetal Biology; warming experiment
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1111/ele.14225

The re‐assembly of plant communities during climate warming depends on several concurrent processes. Here, we present a novel framework that integrates spatially explicit sampling, plant trait information and a warming experiment to quantify shifts in these assembly processes. By accounting for spatial distance between individuals, our framework allows separation of potential signals of environmental filtering from those of different types of competition. When applied to an elevational transplant experiment in the French Alps, we found common signals of environmental filtering and competition in all communities. Signals of environmental filtering were generally stronger in alpine than in subalpine control communities, and warming reduced this filter. Competition signals depended on treatments and traits: Symmetrical competition was dominant in control and warmed alpine communities, while hierarchical competition was present in subalpine communities. Our study highlights how distance‐dependent frameworks can contribute to a better understanding of transient re‐assembly dynamics during environmental change. Graphical text Through our spatially explicit trait‐based approach, we paved the way for a novel framework in community ecology that addresses simultaneously many major issues of the original framework of assembly processes. We used the basic but fundamental knowledge that species coexistence depends not only on their functional but also on spatial distance to unravel the processes acting together in plant communities. The unique combination of our framework with a reciprocal community transplant experiment in the French Alps allowed us to test the framework on assembly processes in mountain grasslands and detect community restructuring under climate change.