Effect of repeated spring drought and summer heavy rain on managed grassland biomass production a

Eva Darenova*, Petr Holub, Lenka Krupkova and Marian Pavelka   2017-07-04 23:26:07

Global Change Research Institute, Czech Academy of Sciences, Belidla 4a, CZ-60300 Brno, Czech Republic

*Correspondence address. Global Change Research Institute, Czech Academy of Sciences, Belidla 4a, CZ-60300 Brno, Czech Republic. Tel: +420 511 192 242; E-mail: darenova.e@czechglobe.cz

Journal of Plant EcologyVOLUME 10, NUMBER 3, PAGES 476–485 June 2017

doi: 10.1093/jpe/rtw058

Advance Access publication 6 June 2016

available online at academic.oup.com/jpe

Abstract

Aims

Ecosystem respiration represents an important component of the carbon cycle. The response of respiration to climate change can have a significant effect on carbon sequestration in terrestrial ecosystems in the future when, according to climate scenarios, spring drought and consequent summer heavy rains are expected. Aims of our study were to determine the effect of repeated spring drought on biomass production and CO2 efflux from a mountain grassland in Beskydy Mountains in the Czech Republic and to evaluate factors driving the differences among the study years.

Methods

CO2 efflux was measured on plots with ambient precipitation conditions (AMB) and on plots where drought conditions (DRY) in the first half of the growing seasons and consequent heavy rain were simulated in 2011–14.

Important

Findings The spring drought significantly decreased the amount of above-ground biomass sampled just after the simulated drought in all years except for 2014. On the contrary, the spring drought stimulated root production. The drought also resulted in a rapid decrease in CO2 efflux. It was lower by up to 46% for the DRY treatment compared to AMB treatment. After the simulated drought period, differences in CO2 efflux between the treatments gradually decreased. Simulated heavy rains in DRY resulted in fast but temporary increase in CO2 efflux. We can assume that the future spring drought will have a significant effect on carbon balance of grassland ecosystems. The impact will depend on the length of the dry period and the time between the beginning of the growing season and the dry period.

Keywords: above-ground biomass, Beskydy Mountains, rainfall manipulation, respiration, rainout shelters, root biomass

Received: 17 December 2015, Revised: 23 May 2016, Accepted: 31 May 2016

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