Over the last decades, Fucus vesiculosus, an ecologically important macroalga in the German Baltic Sea, has shown a massive retreat from the deeper zones of its former distribution presumably due to low light co-acting with other potential stressors such as high temperature, fouling, and grazing. In shallow water F. vesiculosus may be exposed to high water temperatures during summer seasons. Intensity and frequency of heat waves are expected to increase due to climate change which could potentially affect all fucoid life stages. Early life stage processes (fertilization, germination) are often considered particularly sensitive to stress. If the mortality caused by a first heat wave in a genetically diverse population selects for stress resistance, we would expect the survivors to be less sensitive to a second heat wave or possibly even to other stressors like feeding pressure.
In the present study, the mortality of early post-settlement stages of F. vesiculosus under thermal stress and the sensitivity of survived recruits against a proximate stressor (feeding pressure, second heat wave) were analysed by laboratory experiments. The mortality of early fucoid life stages at 25°C, compared to their mortality at 15°C was significantly higher. Regrettably, the ensuing assessment of feeding impact by Idotea baltica and Hydrobia ulvae on the surviving germlings could not be analysed since the two consumer species unexpectedly avoided feeding on the young stages of F. vesiculosus. During the second thermal stress experiment fucoid offspring which was genetically preselected by high temperature (first heat wave: 25°C) differed not significantly in sensitivity from fucoid offspring without prior stress.
A reestablishment of Fucus vesiculosus where it is locally vanished would be an indicator for improved water quality. Thus the Agency for Agriculture, Environment and Rural Areas of Schleswig - Holstein (LLUR) is thinking about opportunities to resettle F. vesiculosus. On behalf of RADOST project, the tolerance of early fucoid life stages towards thermal stress was analysed and after four days of thermal treatment a high percentage of the treated fucoid offspring survived. It might be that inside species genotypes exist which are less sensitive against future environmental changes.
Over the last decades, Fucus vesiculosus, an ecologically important macroalga in the German Baltic Sea, has shown a massive retreat from the deeper zones of its former distribution presumably due to low light co-acting with other potential stressors such as high temperature, fouling, and grazing. Global warming may increase abiotic as well as biotic pressures and exacerbate environmental conditions in coastal ecosystems. The present study focussed on the effects of single or subsequently combined stressors on survival and palatability of juvenile F. vesiculosus. Fucoid offspring were exposed to high temperature and/ or feeding pressure. Feeding preference of Idotea baltica was quantified in a pellet assay calculated as an odds ratio. High temperature significantly impaired the survival of juvenile fucoids. Neither single nor combined stress considerably influenced the feeding preference of I. baltica. Surprisingly I. baltica strictly avoided pellets with juvenile F. vesiculosus compared to adult F. vesiculosus. Avoidance tended to be less pronounced in juvenile fucoids previously stressed by high temperature. Obviously grazing does not induce anti-herbivore defence, but rather the young plants appeared constitutively well-protected against isopod feeding. These results contradict the prevailing opinion that juvenile F. vesiculosus is more susceptible to herbivore grazing than adult F. vesiculosus.
Content:
Regional Activities:
“Lust op dat Meer:” Conclusion and Challenges Ahead;
Quo Vadis – Baltic Sea Coast?
The Sense behind Measurement;
National Activities:
KLIMZUG Status Conference;
New Funding Opportunity for Adaptation Measures;
Communication with Public Agencies and Offices;
International Activities:
Workshop Series: “Climate Knowledge for Regional Coastal
Stakeholders in the Eastern Baltic Sea Region”;
Mussel Farming in the Baltic Sea;
Publications:
Second RADOST Annual Report;
A survey of the perceptions of regional political decision makers
A statistical downscaling method has been developed to produce highly resolved precipitation data from regional climate model (RCM) output, using the model CLM (2 runs, scenario A1B). The procedure is based on the analogue method with the predictors precipitation (daily sums on CLM grid points) and objective weather types (DWD). Analogue days of the time period 2001-2009 are searched using corrected and adjusted data of radar Essen and DWD measurements of objective weather types. The radar data is used to produce high-resolution precipitation data sets (1km², 5min) with realistic spatial and temporal correlations for three catchments in North Rhine-Westphalia. Results in
the reference period (1961 - 1990) are examined using extreme value statistics and compared to corrected station data. Data sets of the near and the far future (2021-2050, 2071-2100) are analysed with respect to future trends, and uncertainties of the downscaling procedure are discussed.
Content:
Regional Activities:
Workshop: Coastal Change as a Challenge for Society, Culture, and Spatial Planning;
RADOST on Tour: Baltic Sea Coast 2100 – On the Way to Regional Climate Adaptation;
Monitoring the Environmental Conditions in the Nearshore Area;
National Activities:
Outstanding Climate Adaptation;
International Activities:
RADOST in Exchange with Coastal Planners in the USA;
Short Film on Climate Change Adaptation in Germany, Poland,
and the Baltic States;
Publications:
Analyses of the Perception of Climate Change Along the
German Baltic Sea Coast;
RADOST Studies on Artificial Reefs
Two circumstances have shaped the vulnerability assessment presented here: the current strong structural dynamics of the energy sector, albeit with no clear direction; and the fact that the energy providers have long been prepared to deal with a large variety of climatic and economic uncertainties.
Political and administrative structures play an important role in climate adaptation. Political scientific analysis can identify factors and scopes of action, which could increase the adaptive capacity. The Governance Team therefore investigated key sectors in the Metropolitan Region, including spatial planning, water management, coastal and inland flood protection,
and civil protection.
Adaptation to climate change requires the implementation of new and revision of existing policies in order to change collective behaviour in a way that reduces vulnerability to the impacts of climate change. At the same time, the efficiency of environmental governance has been questioned due to perceived deficiencies in implementation in the past. As a consequence, it is observed that high levels of adaptive capacity are often not used for adaptive action, and therefore communities remain vulnerable. This thesis is looking at the socio-cognitive dimension of adaptation from the perspective of socio-cultural construction of values and practices that influence risk perceptions and behavioural intentions in coastal management and adaptation to climate variability and change. The construction of values and practices is analysed through discursive fields on the respective topics in local media from three states on the US mid-Atlantic coast.