Biomass‐dependent susceptibility to drought in experimental grassland communities

Abstract

Earlier studies indicated that plant diversity influences community resistance in biomass when ecosystems are exposed to perturbations. This relationship remains controversial, however. Here we constructed grassland communities to test the relationships between species diversity and productivity under control and experimental drought conditions. Species richness was not correlated with biomass either under constant conditions or under drought conditions. However, communities with lower biomass production were more resistant to drought stress than those that were more productive. Our results also showed that ecosystem resistance to drought is a decreasing but nonlinear function of biomass. In contrast, species diversity had little and an equivocal effect on ecosystem resistance. From the results reported here, and the results of several previous studies, we suggest that high biomass systems exhibited a greater biomass reduction in response to drought than low biomass systems did, regardless of the relationship between plant diversity and community biomass production.

Severe water deficit restricts biomass production of Lolium perenne L. and Trifolium repens L. and causes foliar nitrogen but not carbohydrate limitation

“…Both species are highly productive and provide high quality forage for ruminant production, but are known to be susceptible to severe drought events (Goh and Bruce 2005;Hofer et al 2017). Drought events are projected to increase in frequency and severity in temperate regions due to climate change (Seneviratne et al 2012;Trenberth et al 2014), and experimental evidence suggests that highly productive grasslands could be more impaired by drought than low productivity grasslands (Pfisterer and Schmid 2002;Wang et al 2007). An increased understanding of the drought-related mechanisms leading to yield losses of these economically important species could serve to improve their performance under conditions of soil water deficits through management and/or breeding practices.…”

Do successive climate extremes weaken the resistance of plant communities? An experimental study using plant assemblages

“…This explanation is in line with other experiments that observed a stronger negative effect of drought on plant communities containing greater nitrogen stocks, either through the presence of legumes (Pfisterer and Schmid, 2002;Kreyling et al, 2008) or through manually added nitrogen (Gordon et al, 1999;Keller, 2005), as these communities were more productive. Furthermore, other studies have also related ecosystem productivity to drought sensitivity (van Ruijven and Berendse, 2010;Van Peer et al, 2001, 2004Wang et al, 2007). This implies that plant community composition and/or ecosystem fertility are essential predictors for the response of a community to drought extremes.…”

Communities of different plant diversity respond similarly to drought stress: experimental evidence from field non-weeded and greenhouse conditions

“…These two mechanisms are not easy to separate and are the subject of many debates (Duffy 2009;Hillebrand and Matthiessen 2009). On the other hand, although positive effects occurred frequently in manipulated systems, there were also documented non-consistent effects of plant diversity on productivity (Huston et al 2000;Balvanera et al 2006;Wang et al 2007). This becomes important when considering the ecosystem's responses to perturbation in the sense of stability properties, which may depend on the form of the relationships between diversity and productivity, as indicated in various grassland experiments (Pfisterer and Schmid 2002;Wang et al 2007;De Boeck et al 2008;van Ruijven and Berendse 2010).…”