title: Gewässer: Mehr als Wasser
Creators: name: Hering, Daniel
name: Leese, Florian
name: Haase, Peter
Publisher: name: DuEPublico: Duisburg-Essen Publications online, University of Duisburg-Essen, Germany
Year: 2018
Subjects: subject: 570

description: Gewässer sind prägende Elemente der Landschaft. Bäche und Flüsse bilden ein dichtes Netzwerk, sie verbinden Landschaftselemente und Siedlungen. Seit jeher nutzt der Mensch die Gewässer auf vielfältige Art und Weise. Diese Nutzungen bleiben nicht ohne Auswirkungen auf den Naturhaushalt und auf die Nutzbarkeit der Gewässer.
description: Applied limnology deals primarily
with the effects of stressors on freshwater
ecosystems and with measures
for mitigating stressors and restoring
degraded water bodies. It contributes
to the development of methods
for the assessment and restoration
of freshwater ecosystems, but also
to the refinement and implementation
of policies, in Europe in particular
to the implementation of the
Water Framework Directive (WFD).
According to this directive, the
target of water management is not
only good water quality, but “good
ecological quality”, measured as the
distance of freshwater biota to undisturbed
references. Working groups
of the University of Duisburg-Essen
have greatly contributed to develop
assessment methods measuring ecological
quality, which are based on
profound knowledge of how individual
freshwater species respond
to a variety of stressors, including
various sources of pollution, habitat
degradation and flow alteration. The
data are summarized in the online
database www.freshwaterecology.
info. Currently, the methods
are undergoing a major shift from
morphology-based species identification
to automated DNA-based
identification, which is driven by the
EU-funded COST action DNAqua.
Net, coordinated by the University
of Duisburg-Essen. According to the
assessment systems’ results, about
half of the European water bodies
are currently not reaching “good
status”, but the causes of degradation
differ regionally: while in Northern
Europe the effects of water power
generation and remnants of acidification
are predominant factors,
Southern European water bodies
are particularly affected by water
scarcity caused by irrigation. In
Central Europe, many different
stressors at medium intensity affect
water bodies simultaneously, including
input of nutrients, pesticides
and fine sediment and, in particular,
hydromorphological degradation.
To restore degraded water bodies, a
large number of restoration projects
have been initialised over the last
couple of years, the effects of which
were intensively studied by scientists
of the University of Duisburg-
Essen. The effects of restoration
measures on freshwater biota vary,
with floodplain organism groups (e.g.
riparian ground beetles) responding
most rapidly, while the response
of most aquatic organism groups is
delayed. Using a paired study design,
it could be revealed that the length of
the restored section does not greatly
impact the restoration success, but
the amount of habitat changes on the
river bottom is of great importance.
Recolonization of restored river
reaches with sensitive organisms is
mainly based on colonization sources
in the immediate surroundings (up to
five-kilometer distance). A detailed
study on recolonization was performed
in the Emscher catchment,
which offers great opportunities for
studying the succession of newly
established freshwater assemblages.
description: UNIKATE: Berichte aus Forschung und Lehre, no. 51Herausforderung Wasserforschung - lokal, regional, global, p. 48