Abstract On planet Earth, all elemental cycles are interconnected through coupled biotic and abiotic processes, including climate, water availability and variability, soil‐forming factors and plant–animal–microbial interactions. Variations in these factors, which may be driven by anthropogenic factors such as climate change and community reorganizations, may affect the bioavailability and abundance of chemical elements, 17 of which are essential nutrients for plants. Differential responses among chemical elements may, in turn, lead to changes in their interrelationships, resulting in the coupling or decoupling of elemental cycles across different ecosystem compartments (e.g. animals, plants and soils). We analysed the impact of experimentally altered rainfall regimes (reduced amount and frequency) and root herbivory (through the addition of scarab beetle larvae) on the bioavailability, abundance and coupling of 11 soil and 14 plant elements in an Eastern Australian grassland. We also examined how elemental coupling may be influenced by the atomic properties of those elements, particularly atomic mass, which is closely linked to each element's abundance, reactivity and mobility in soils and plants. Overall, plant elemental content was not significantly affected by the experimental manipulations, reflecting a high degree of homeostatic regulation. In contrast, soil nutrient bioavailability responded more strongly to changes in rainfall, with the bioavailability of potassium increasing and that of secondary macronutrients such as calcium and magnesium and micronutrients such as manganese decreasing under altered precipitation scenarios. Plant elements were generally more coupled than those in soil, reflecting stronger internal regulation (i.e. homeostasis), but this coupling was significantly influenced by both experimentally altered rainfall and root herbivory. Plant coupling was generally reduced in response to rainfall manipulation, while the effects of herbivory were highly rainfall treatment‐ and year‐dependent. Additionally, we found signals of a positive association between elemental coupling and atomic mass in soils, whereas no such relationship was detected in plants. Synthesis . Our work provides novel experimental evidence on how chemical elements in plants and soils respond to changes in precipitation regimes and shifts in plant–animal interactions (root herbivory), moving the focus from changes in plant and soil elements to the way in which such elements are coordinated.
Ochoa‐Hueso et al. (Fri,) studied this question.