Number of simultaneously acting global change factors affects composition, diversity and productivity of grassland plant communities

Abstract

Plant communities experience impacts of increasing numbers of global change factors (e.g., warming, eutrophication, pollution). Consequently, unpredictable global change effects could arise. However, information about multi-factor effects on plant communities is scarce. To test plant-community responses to multiple global change factors (GCFs), we subjected sown and transplanted-seedling communities to increasing numbers (0, 1, 2, 4, 6) of co-acting GCFs, and assessed effects of individual factors and increasing numbers of GCFs on community composition and productivity. GCF number reduced species diversity and evenness of both community types, whereas none of the individual factors alone affected these measures. In contrast, GCF number positively affected the productivity of the transplanted-seedling community. Our findings show that simultaneously acting GCFs can affect plant communities in ways differing from those expected from single factor effects, which may be due to biological effects, sampling effects, or both. Consequently, exploring the multifactorial nature of global change is crucial to better understand ecological impacts of global change.

Factors of global change affecting plants act at different levels of the ecological hierarchy

“…This study employed a combinatorial design, using random draws from a pool of factors to generate an experimental gradient in factor number, deemphasizing factor identity, and composition. Very similar effects have also been found for plants, exemplified by experimental work on Arabidopsis Zandalinas, Sengupta, et al, 2021), tomato (Pascual et al, 2023), soybean (Pel aez-Vico et al, 2023), rice and maize (Sinha et al, 2022), and also for plant communities experimentally exposed to up to six factors of global change (Speißer et al, 2022). More recently, a global observational study has also found the signature of a number of factors in the biodiversity and ecosystem function data encompassing over 200 different ecosystems (Rillig et al, 2023).…”

Herbivory and elevated levels of CO2 and nutrients separately, rather than synergistically, impacted biomass production and allocation in invasive and native plant species

“…However, the positive plant growth response to CO 2 enrichment can be constrained by nutrient limitation (Jiang et al, 2020; Reich et al, 2006). Given that ecosystems often experience multiple global environmental changes simultaneously (Brennan et al, 2017; De Laender, 2018), gaining a mechanistic understanding of how interactions among multiple drivers of environmental change influence plant growth may aid in predicting future global patterns of vegetation productivity and ecosystem functioning (Speißer et al, 2022). Knowledge of the interactive effects of a rise in CO 2 concentrations and nutrient enrichment on invasiveness of alien plants is therefore necessary.…”

Plant community diversity alters the response of ecosystem multifunctionality to multiple global change factors

“…Taken together, these mixed effects indicate that the impacts of global change factors on ecosystem multifunctionality are complex (Eisenhauer et al., 2018) and that interactions between multiple global change factors might counteract or intensify the effects of single global change factors on ecosystem multifunctionality in natural ecosystems. Therefore, studies that investigate the interactive effects of multiple global change factors on ecosystem multifunctionality will be an important future research direction, especially as global change is only predicted to worsen in the future (Barreto & Lindo, 2022; Rillig et al., 2019; Song et al., 2019; Speißer et al., 2022).…”