Low resistance of montane and alpine grasslands to abrupt changes in temperature and precipitation regimes

Bernd Josef Berauer,Peter A Wilfahrt,Mohammed A S Arfin-Khan,Pia Eibes,Andreas Von Heßberg,Johannes Ingrisch,Michael Schloter,Max A Schuchardt,Anke Jentsch

doi:10.1080/15230430.2019.1618116

Abstract

ABSTRACTHigh-elevation ecosystems will experience increasing periods of above-average warmth and altered precipitation changes because of climate change. This causes uncertainties for community properties such as productivity and biodiversity. Increasing temperature may increase productivity by increasing growing season length and metabolic rate or decrease productivity by causing drought stress. Competitive outcomes between species may change with altered climatic conditions, causing shifts in community composition. This study investigates the resistance of aboveground biomass and plant community composition of montane and alpine grassland ecosystems to abruptly altered temperature and precipitation conditions. Intact plant-soil communities were translocated downslope spanning an elevational gradient of 2,090 m in the European Alps. We hypothesize that increasing temperature leads to (1) increased aboveground biomass in the absence of precipitation deficits, (2) decreased species richness, and (3) shifts in plant community composition. After one year of exposure to their new environment, aboveground biomass changes appeared to be dependent on precipitation regimes, whereas species richness declined consistently with changed climatic conditions. No deterministic shift in community composition was found. Abrupt changes in climatic conditions can lead to rapid responses of community properties, indicating that these high-elevation communities may have low initial resistance to future heat waves and droughts.

Highlights

Temperature rise because of anthropogenic climate change is expected to be most extreme at high latitudes and elevations (Ceppi et al 2012; Gobiet et al 2014; Pepin et al 2015)
After a full year of exposure to these new environments, changes in aboveground biomass of the montane and alpine grassland communities did not correlate with elevational distance or thermal time (GDD) changes because of translocation
We found no significant effect of change in elevational distance, thermal time (GDD), or precipitation on the relative proportion of the plant functional groups graminoids, forbs, or legumes to community aboveground biomass

Summary

Introduction

Temperature rise because of anthropogenic climate change is expected to be most extreme at high latitudes and elevations (Ceppi et al 2012; Gobiet et al 2014; Pepin et al 2015). Temperature is a fundamental regulator of chemical and biological processes and is likely to both directly and indirectly affect plant community properties (Rustad et al 2001). Higher metabolic rates at higher temperatures (Billings and Mooney 1968; Lucht et al 2002; Larcher 2003) may increase the plant productivity of cold-adapted ecosystems. This may occur directly via the damage of tissue or overheated photosystems (Larcher 2003; Buchner et al 2015) Well before such extremes, temperature can indirectly reduce productivity via reduced soil-water availability resulting from increased evapotranspiration and altered precipitation regimes (De Boeck et al 2016). These conflicting drivers may explain why Supplemental data for this article can be accessed here

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Conclusion