Climate-driven in-situ trait variation in an annual ruderal grass across Europe
Helene Villhauer, Timo Hellwig, Sandy Jan Labarosa, Sabine Metzger, Jonathan Moore, Adrian Wysocki, Henryk Straube, Denise V M Blume, Jannis Straube, Walter Durka, Milan Brankov, Kamil Konowalik, Matej Lexa, Abdenour Kheloufi, Lahouaria Mounia Mansouri, José Manuel Blanco Moreno, Pablo Neira, Joel Torra, Aritz Royo-Esnal, Luís P da Silva, Francesco Santi, Anis Edena Zarantonello, Encarna Rodríguez-García, Carmen Romeralo, Arndt Hampe, Víctor Manzanares-Vázquez, Monika Myśliwy, Anna Bomanowska, Konrad Kaczmarek, Marta Kolanowska, Agnieszka Rewicz, Nebojša Nikolić, Ondřej Mudrák, Marcin Nobis, Agnieszka Nobis, Boris Radak, Miloš Ilić, Przemyslaw Baranow, Sławomir Nowak, Artur Nosalewicz, Izabela Krzemińska, Anna Elisabeth Backhaus, Katalin Szitár, Severin Einspanier, Sylvain Pincebourde, Mathieu Leclerc, Markus Wagner, Nadine Mitschunas, Albane Bignon, Ali Sahri, Arne Saatkamp, Andreas D Drouzas, Stanislav Kopriva, Maria von Korff, Anna BucharovaAbstract
Background and Aims
Plant functional traits link environmental conditions to plant performance and adaptation. Growing evidence suggests that intraspecific trait variation can be as important as differences between species, yet large intraspecific studies of in-situ variation remain rare. While most studies have focused on plant morphological traits, the concentrations of elemental nutrients in seeds have received much less attention so far.
Methods
We conducted a large-scale in-situ study of the widespread annual ruderal grass Hordeum murinum. We sampled 2070 individuals from 207 populations across a large part of its native range in Europe and North Africa. We measured seed ripening phenology and growth-related traits in-situ and analyzed concentrations of elemental nutrients in the seeds.
Key results
We found that Hordeum murinum grew larger, produced seeds later, and had heavier seeds in colder and wetter regions. Plants growing in denser vegetation were taller and produced heavier seeds but formed fewer spikes. Concentrations of elemental nutrients in the seed generally declined with seed weight and were primarily driven by climatic variables, whereas soil conditions had only minor effects on plant traits and seed nutrients. Population identity explained a substantial proportion of trait variation, indicating a possible genetic component.
Conclusions
Our findings provide a comprehensive view of how Hordeum murinum responds to environmental gradients across its European distribution. Climatic variables, particularly temperature, are key drivers of reproductive timing and concentrations of elemental nutrients in the seed, whereas local environmental conditions, such as biotic pressures, are more critical for growth-related traits. Together, these patterns indicate that Hordeum murinum modulates its growth and reproductive investment along environmental gradients, balancing phenology, stress tolerance, and limited competitive capacity.