Synchrony matters more than species richness in plant community stability at a global scale

Abstract

The stability of ecological communities is critical for the stable provisioning of ecosystem services, such as food and forage production, carbon sequestration, and soil fertility. Greater biodiversity is expected to enhance stability across years by decreasing synchrony among species, but the drivers of stability in nature remain poorly resolved. Our analysis of time series from 79 datasets across the world showed that stability was associated more strongly with the degree of synchrony among dominant species than with species richness. The relatively weak influence of species richness is consistent with theory predicting that the effect of richness on stability weakens when synchrony is higher than expected under random fluctuations, which was the case in most communities. Land management, nutrient addition, and climate change treatments had relatively weak and varying effects on stability, modifying how species richness, synchrony, and stability interact. Our results demonstrate the prevalence of biotic drivers on ecosystem stability, with the potential for environmental drivers to alter the intricate relationship among richness, synchrony, and stability.

Temporal stability of biomass in annual plant communities is driven by species diversity and asynchrony, but not dominance

“…In contrast to other studies in a wide range of ecosystems (Valencia et al, 2020), species evenness and temporal stability of dominant species were not significant drivers of biomass stability in the mediterranean and semi-arid annual plant communities.…”

Defining codominance in plant communities

“…Current frameworks around this fundamental question rest on two foundations: niche differences and relative fitness differences among coexisting species. However, the relative importance of the roles that these aspects play are imperfectly understood (Levine & HilleRisLambers, 2009; Carroll et al ., 2011; HilleRisLambers et al ., 2012; Kraft et al ., 2015; Valencia et al ., 2020) and are likely to be variable (Chase & Myers, 2011; HilleRisLambers et al ., 2012). For instance, sets of codominant species that exhibit similar degrees of shared abundance but contrasting degrees of functional similarity (e.g.…”

“…In addition to sharing in the control of the magnitude of expression of ecosystem function, codominant species can affect the spatial and temporal variability in ecosystem function when they differ in their responses to changing environmental conditions, (Loreau et al ., 2003; Shanafelt et al ., 2015). This, in turn, can result in enhanced temporal stability of those functions (Valencia et al ., 2020). For instance, if in one year environmental conditions favour biomass production of one species more so than its codominant, and the next year favours the latter over the former, variance in community biomass productivity over those two years will be lower than in an ecosystem that experiences the same environmental variability but is mono‐dominated by either one of the two species (Wilcox et al ., 2017).…”

“…Danin, 1978; Woods, 1979; Kuebbing et al ., 2015). Where they occur, codominant plant species are distinct from uncommon (or subordinate, Grime, 1998) species, in that they also can control a large proportion of ecosystem function (Silletti & Knapp, 2002; Ma et al ., 2020; Valencia et al ., 2020). The often‐observed pattern that ecosystems are frequently characterised by a few abundant and many rare species (e.g.…”

Hydraulic diversity stabilizes productivity in a large-scale subtropical tree biodiversity experiment

“…It is made The copyright holder for this preprint this version posted January 7, 2021. ; https://doi.org/10.1101/2021.01.06.425434 doi: bioRxiv preprint buffering effect of biodiversity in forest ecosystems. Various mechanisms may decrease temporal variation in productivity 14,16,21,22 but arguably the one most supported by theoretical and observational studies in grasslands and increasingly also in forests is species asynchrony 7,21,23 . In forests, these asynchronous inter-annual dynamics in productivity among tree species (hereafter 'species asynchrony' 22 ) have been found to be the strongest driver of community stability in some 6,24,25 but not all studies 11 .…”