Increasing climatic sensitivity of global grassland vegetation biomass and species diversity correlates with water availability.

Daijun Liu,Romà Ogaya,Marcos Fernández-Martínez,Chao Zhang,Thomas A M Pugh,Josep Peñuelas

doi:10.1111/nph.17269

Abstract

SummaryGrasslands are key repositories of biodiversity and carbon storage and are heavily impacted by effects of global warming and changes in precipitation regimes. Patterns of grassland dynamics associated with variability in future climate conditions across spatiotemporal scales are yet to be adequately quantified. Here, we performed a global meta‐analysis of year and growing season sensitivities of vegetation aboveground biomass (AGB), aboveground net primary productivity (ANPP), and species richness (SR) and diversity (Shannon index, H) to experimental climate warming and precipitation shifts. All four variables were sensitive to climate change. Their sensitivities to shifts in precipitation were correlated with local background water availability, such as mean annual precipitation (MAP) and aridity, and AGB and ANPP sensitivities were greater in dry habitats than in nonwater‐limited habitats. There was no effect of duration of experiment (short vs long term) on sensitivities. Temporal trends in ANPP and SR sensitivity depended on local water availability; ANPP sensitivity to warming increased over time and SR sensitivity to irrigation decreased over time. Our results provide a global overview of the sensitivities of grassland function and diversity to climate change that will improve the understanding of ecological responses across spatiotemporal scales and inform policies for conservation in dry climates.

Highlights

Ongoing global climate change, characterised by warming and spatiotemporal shifts in patterns of precipitation, is affecting species diversity and composition, and plant carbon accumulations across communities and ecosystems (Hooper et al, 2012; Scheffers et al, 2016; Thakur et al, 2017; Nolan et al, 2018)
Growing season sensitivities of vegetation growth and community composition were affected by climate treatments (Fig. 1c), where aboveground biomass (AGB) and aboveground net primary productivity (ANPP) sensitivity were positive under irrigation
Our global meta-analysis quantified responses of grassland vegetation biomass and species diversity to manipulated climate conditions using the proportional change in vegetation functioning (AGB and ANPP) and species diversity (SR and H) per unit net change in manipulated temperature or precipitation

Summary

Introduction

Ongoing global climate change, characterised by warming and spatiotemporal shifts in patterns of precipitation, is affecting species diversity and composition, and plant carbon accumulations across communities and ecosystems (Hooper et al, 2012; Scheffers et al, 2016; Thakur et al, 2017; Nolan et al, 2018) These changes in temperature and precipitation are likely to increase in both frequency and intensity in the coming decades, during which warmer and drier climates are predicted to prevail across large areas of the globe, with conditions at higher latitudes likely to become wetter (Pen~uelas et al, 2017; Hoegh-Guldberg et al, 2018; Nolan et al, 2018). These impacts may be especially severe under the high-emission RCP 8.5 (representative concentration pathway) scenario (Nolan et al, 2018; Berdugo et al, 2020; Trisos et al, 2020)

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Discussion

Conclusion