FRANKFURT. In the framework of the
“South Hesse Oak Project” (SHOP), researchers from the Institute of Ecology,
Evolution and Diversity at Goethe University are searching for new strategies
to counteract the formation of steppe habitats out of woodlands, which is to be
feared as a result of climate change in dry areas in South Hesse. They have now
presented first strategic recommendations.
Summers in Central Europe
are becoming hotter, summer rainfall less and droughts longer and more
frequent. Climate change is altering weather patterns and having an impact on
woodlands in the process. Where water supply is at present still good, climate
change is expected to lead to only a moderate shift in species composition
towards varieties that can cope better with drought in the medium term.
Woodlands which, however, are already growing in extreme conditions with poor
water supply today will not survive future droughts unharmed. This can already
be seen in a large part of Frankfurt City Forest, where as a result of the 2018/19
droughts a total of 97 per cent of all trees are damaged. That is why
researchers from the Institute of Ecology, Evolution and Diversity at Goethe
University are exploring in the “South Hesse Oak Project” (SHOP) which
strategies can counteract the loss of woodlands, in order to preserve them as a
habitat characterised by rich biodiversity and as a CO2 store
despite rapidly advancing climate change.
They have now presented
first strategic recommendations:
- Mildly affected areas, where water supply will remain sufficient in
future, are in principle able to defy climate change without anthropogenic
intervention through natural regeneration of the tree population, climatic
selection of individual varieties and adjustment of species composition.
- For moderately affected areas where increasing drought damage is to be
expected, targeted reforestation with drought-resistant endemic tree varieties,
such as sessile oak or Scots pine, is a suitable approach.
- In strongly affected regions, such as the sandy ground in the Rhine-Main
area, it is necessary to plant varieties from drier climate zones.
Mediterranean varieties or species are possible here, as are ones from
The “Ecophysiology of
Plants” working group at Goethe University began studying Mediterranean oak species
as long ago as 2007. In 2009 at the start of the LOEWE “Biodiversity and Climate
Research Centre” (BiK-F), the project born out of it – “The Forest of the
Future” – was rewarded with the “Landmark in the Land of Ideas” innovation
prize. Out of this project, SHOP developed in 2011 in cooperation with external
The project is concerned
with the introduction of Mediterranean oaks as alternative tree species. “Here
in Germany, pedunculate oak is one of the ecologically most important forest trees,”
says Wolfgang Brüggemann, biology professor and head of SHOP. “However, it
frequently grows in extremely dry areas and will therefore be particularly
severely affected by climate change.” Alternative tree species must not only be
more resistant to drought than pedunculate oaks but also endure the winters
here, which today are still cold. An important aspect for the researchers is
that these tree species can also take on the ecological functions of the ones lost.
“In order not to weaken the ecosystems further, it’s important to maintain
biodiversity,” says Vera Holland, postdoctoral researcher at the Institute of
Ecology, Evolution and Diversity.
In the framework of SHOP –
and the “Futureoaks-IKYDA” collaborative project developed out of it in 2017
with partners from Italy and Greece – between 2009 and 2017 the researchers
planted more than 10,000 oaks at four sites in South Hesse as well as in Greece
and Italy. They have studied their growth, physiology, ecological potential and
molecular biology over many years. The results of their research work
substantiate that some Mediterranean oaks have excellent potential for being
planted as alternative tree species in strongly affected areas, for example the
downy oak (Quercus pubescens) or –
under certain conditions – the evergreen holm oak (Quercus ilex).
“On the basis of
model-assisted forecasts, a shift in the distribution ranges of Mediterranean species
in the direction of Central Europe as a result of climate change has already
been predicted for years,” says Vera Holland. “However, climate change is advancing
far more rapidly than the natural immigration of these varieties can firstly keep
pace with and secondly fill the holes quickly enough that are caused by extreme
weather events. The introduction of the Mediterranean species propagated by us
via assisted migration would bridge this process and thus preclude the loss of
woodland, a major drop in CO2 storage and accelerated soil erosion
in deforested areas,” she says.
Further information: Professor Wolfgang Brüggemann, Institute
of Ecology, Evolution and Diversity, Faculty of Biological Sciences, Riedberg
Campus, +49(0)69-79842192, email@example.com