Consequences of the 2018 summer drought
Research team investigates effects on plants, forests and grassland

Date:
September 9, 2020
Source:
University of Go"ttingen
Summary:
The drought that hit central and northern Europe in summer 2018
had serious effects on crops, forests and grasslands. Researchers
are showing what effects this had and what lessons can be learned.



FULL STORY ==========================================================================
The drought that hit central and northern Europe in summer 2018 had
serious effects on crops, forests and grasslands. Researchers from the
European Research Infrastructure Integrated Carbon Observation System
(ICOS), including researchers from the University of Go"ttingen, are
showing what effects this had and what lessons can be learned. The
results of 16 studies that are currently underway have been published
as a special issue in the journal Philosophical Transactions.


==========================================================================
The interdisciplinary teams shed light on different aspects of this
research.

Among many findings, they found that the plants initially benefited
from the warm and sunny conditions in spring, but had too little water available for their roots when the summer heatwave started. As a result, grasslands began to dry up and numerous arable areas recorded the lowest
yields for decades. The forests protected themselves by greatly reducing
their evaporation for several weeks, but this then led to a sharp drop
in carbon dioxide uptake. Such effects were observed simultaneously --
all the way from Switzerland to the Netherlands and Germany, and from
the Czech Republic to Sweden and Finland.

The Bioclimatology Group of the Faculty of Forest Sciences and Forest
Ecology at the University of Go"ttingen contributes to ICOS with
a meteorological station in the Hainich National Park. For the last
20 years every 30 minutes, the station has measured the carbon dioxide
(CO2) and water vapour exchange between forest and atmosphere. Comparing
the data across Europe shows that the area under investigation is one
of those most affected by the 2018 drought. "In 2018, the CO2 uptake
calculated over the whole year was about 30 percent lower than the
average of the past 20 years," says Head of the Group Professor Alexander Knohl. "On some days in the summer of 2018, the forest actually emitted
carbon dioxide instead of absorbing it," adds Dr Lukas Siebicke. "In
the past 20 years, this has never happened before." The measurements
from the meteorological station in the Hainich National Park are of
great international scientific importance for two reasons: it is one
of the world's longest time series for such continuous measurements;
and it is one of the oldest unmanaged forests in which such measurements
of carbon dioxide and water vapour exchange takes place.

ICOS is a European research infrastructure for measuring carbon dioxide
fluxes between land, ocean and atmosphere. Across Europe, 140 measuring stations in twelve countries are involved. ICOS stations are subject to a rigorous quality assurance process and provide standardised data that is
made freely available for research, teaching and other applications. ICOS provides essential data for the reports of the Intergovernmental Panel
on Climate Change (IPCC) and for the decision-making processes within
the UN Framework Convention on Climate Change.


========================================================================== Story Source: Materials provided by University_of_Go"ttingen. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Wouter Peters, Ana Bastos, Philippe Ciais, Alex Vermeulen. A
historical,
geographical and ecological perspective on the 2018 European
summer drought. Philosophical Transactions of the Royal
Society B: Biological Sciences, 2020; 375 (1810): 20190505 DOI:
10.1098/rstb.2019.0505 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200909114739.htm

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