Georg A. Janauer

University of Vienna | UniWien · Department of Limnology and Biological Oceanography

The Danube is the second-longest river in Europe that is subjected to various man-made alterations, including those related to hydro-power plants. We surveyed and analyzed the presence and abundance of macrophytes in the main channel from 2582 river kilometers (rkm) to 171 rkm. We also assessed selected habitat parameters in the sampled river stret...

This study was carried out in the Bucegi Natural Park, a protected area of the Romanian Carpathians. It aims at documenting the potential sensitivity of six widespread Natura 2000 habitat types and of all plants with conservative value (200 taxa) in the mountain area, to the changes in temperature and humidity, predicted for this century. Regional...

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Anthropogenic impacts on carp pond environments have increased over the last 100–150 years in Central Europe. Present semi-intensive carp pond management combines natural food resources, supplementary feeding and additional intensification measures such as manuring, liming, and winter and summer drainage. Despite increased eutrophication and fish s...

Intensively used urban water bodies are vulnerable to eutrophication. The shallow lake Alte Donau (Vienna) can be seen as an example for the extent of anthropogenic influence. Human impacts paired with changes in environmental conditions gave way to eutrophication processes in Alte Donau. Due to the great public interest restoration concepts and su...

Intensively used urban water bodies are vulnerable to eutrophication. The shallow lake Alte Donau (Vienna) can be seen as an example for the extent of anthropogenic influence. Human impacts paired with changes in environmental conditions gave way to eutrophication processes in Alte Donau. Due to the great public interest restoration concepts and su...

An overview is given on the development of the survey method specifcally developed for aquatic macrophyte assessment and associated environmental parameters. Te method was developed and tested within the international Expert Group for Macrophytes of IAD, which formed the core group of surveyor teams and reporting authors in the MIDCC project. Tis m...

In Bavaria the Danube flows through the four administrative districts of Bayerisch Schwaben, Oberbayern, Oberpfalz and Niederbayern. Cities like Ulm, Regensburg and Passau are located along this river stretch, and several hydro power plants intersect the river flow. Tis contribution presents floristic characteristics of the aquatic macrophytes (bryoph...

Aquatic macrophyte diversity, distribution and abundance as well as associated environmental parameters are presented for the Romanian Danube River corridor. Parts of the main channel, river arms and Delta channels are considered as characteristic examples of the 2,483 river-kilometres investigated in our study. Te main geomorphological regions of...

Today the longitudinal and lateral connectivity of the Austrian Danube River Reach is disturbed by a series of hydropower plant reservoirs. Additionally rip-rap and concrete fxtures defning the regulated main channel of the international navigation corridor restrict the hydrological exchange with former riparian zones, but two free flowing stretches...

We hypothesize that the physical features of river habitats and anthropogenic hydromorphological alterations influence macrophyte communities and lead to habitat fragmentation. Sampling included 1081 contiguous survey units positioned in the main channel and side arms along 588km of the Danube River, along its middle course. To identify habitat fra...

Little information is available for aquatic plants regarding their architectural response to strong environmental drivers like water flow. We examined architectural variability in Myriophyllum spicatum L. in the short terminal section of a small canal earlier used for inland navigation. This stretch is characterised by decreasing water depth toward...

The Lobau wetland and oxbow ensemble is part of the large Danube River floodplain area between Vienna (Austria) and Bratislava (Slovakia). The Danube River regulation scheme implemented in the late 19th century considerably affected the Lobau area, which is part of the Danube National Park today. Terrestrialization processes in the floodplain start...

Our objectives were to offer insight into the characteristics of the physical environment in the River Danube in Serbia; and to show the relationship between selected environmental factors and the composition and abundance of macrophyte species. The macrophyte survey method followed the European Standard EN 14184, applying Kohler’s five-level descr...

The longest reach of the Danube River borders, or crosses the Romanian territory, respectively. The composition and distribution of aquatic vegetation is specific for the diversity of the channel types in the Danube River corridor. Increased eutrophication stimulates the development of some well-adapted cormophytes (Sârbu 2006). Therefore, special...

Using the ecohydrology concept for mitigating or resolving pressures on the natural environment caused by human activities is a successful way to find low-technology solutions which comprise the use of ecosystem services provided by dedicated ecosystems. Today this approach faces constraints by lack of area in highly developed countries, or related...

There is general agreement among scientists that global temperatures are rising and will continue to increase in the future. It is also agreed that human activities are the most important causes of these climatic variations, and that water resources are already suffering and will continue to be greatly impaired as a consequence of these changes. In...

n BRAHMATWINN the upper Danube river basin (UDRB) and the upper Brahmaputra river basin (UBRB) were selected as the representative catchments in two mountain-dominated geographical regions. Three test sites were selected in the UBRB: the Lhasa River catchment in Tibet/China, the Wang Chu river catchment in Bhutan, and the Assam reach of the Brahmap...

The EU water framework directive (WFD) is intensively connected with other European legal regulations and supporting documents. This close interrelationship calls for deeper considerations when WFD is implemented in locations of high conservation value, e.g. Natura 2000 sites. A comprehensive, but specific comparison of the goals of WFD with the ai...

Recording and assessment of aquatic macrophytes was a request for the Joint Danube Survey 2 (JDS2). New insight regarding occurrence, abundance and specific distribution of macrophytes was based on methodological adaptations better adjusted to the size of this large European river and permitted more appropriate statistical interpretation. Regarding...

The implementation of adaptation actions in local conservation management is a new and complex task with multiple facets, influenced by factors differing from site to site. A transdisciplinary perspective is therefore required to identify and implement effective solutions. To address this, the International Conference on Managing Protected Areas un...

Floodplain lakes and associated wetlands in tropical dry climates are controlled by pronounced and severe seasonal hydrologic fluctuations. We examined the plant community response to a bimodal flooding pattern in the Zapatosa Floodplain Lake Complex (ZFLC), Northern Colombia. We measured floristic and quantitative change in four sampling periods e...

Climate change impacts biota from individual level to whole habitats. Changing regional climate conditions let individuals be more prone to catastrophic disturbances (e.g. disease, insects, or fires). Climate change exposures and the sensitivity of species and habitats against these exposures can be used to assess the potential impacts on habitats....

This chapter outlines the general relationships between aquatic macrophytes and their hydraulic environment. It examines how aquatic plants react to the conditions experienced within their habitat. An extensive review of the controls of flow on macrophytes in lowland rivers demonstrates the importance of discharge and flow velocity on macrophyte co...

Riverine landscapes are shaped by the spatio-temporal dynamics of the water regime. Water level transitions induce a shift in plant species composition from aquatic to ephemeral vegetation communities in riparian habitats. Hence, the occurrence of these ephemerals is strongly related to the hydrological connectivity and therefore used as indicator...

We investigated the macrophyte community in a free flowing stretch of the Danube downstream of Vienna, Austria. Aim of the study was to analyze the macrophyte - habitat relationship with respect to depth and connectivity. Habitat types (HT-1 to HT-5) paralleled those introduced within the Floodplain Index, i.e. they represent a gradient from perman...

This work assesses wetland landscape dynamics in the Deepor Beel of Brahmaputra basin using multi-temporal satellite imagery. An attempt has also been made to link the wetland changes with the turbidity pattern observed from satellite imagery. In addition, this paper also highlights application of rule-based decision tree classification of satellit...

This work assesses wetland landscape dynamics in the Deepor Beel of Brahmaputra basin using multi-temporal satellite imagery. An attempt has also been made to link the wetland changes with the turbidity pattern observed from satellite imagery. In addition, this paper also highlights application of rule-based decision tree classification of satellit...

Based on field surveys carried out between 2002 and 2004 the aquatic macrophyte vegetation of all the main Tisza oxbows was assessed as part of the Tisza River Project. Examples are given for the wide amplitude of morphological parameters and of the range in species composition, in map form as regards the lateral development of the cutoff river par...

Climate change is one of the most severe threats to the environment in this century. Its possible effects on the aquatic vegetation in river and floodplain habitats are described by relation to carbon dioxide, temperature, precipitation and water discharge, as well as species migration and alien aquatic plants. Potential conflicts between river res...

The complexity of water bodies in the eu-potamal river corridor and the main delta channels of the Romanian Danube is exemplified by the macrophyte vegetation. Two hypotheses provided the background for our study: (a) is the macrophyte vegetation of large, permanently connected branches significantly separated from that of the main river channel; (...

Water currents are among the strongest environmental variables determining the occurrence and/or abundance of aquatic plants and the European Water Framework Directive (WFD) considers river morphology and current conditions important aspects of reference conditions. We used the database of the Joint Danube Survey JDS-2, organised by the Internation...

Introduction Aquatic macrophyte communities play a key role in aquatic ecosystems, structuring the water column, stabilising the substrate, providing microhabitats for other aquatic biota and contributing to the oxygen and carbon budget of the water body (Haslam 1978, Janauer & Dokulil 2006). They change in a more dynamic way than terrestrial veget...

As part of a study on stem rigidity of Common Reed (Phragmites australis Cav. Trin ex Steud.), grown in natural habitats and in constructed wetlands, authors tried to prepare anatomical sections of node regions of dried material used for the assessment of me- chanical parameters. Sections should especially show location and number of vascular bundl...

Hydro-acoustic methods are commonly used to estimate the abundance and distribution pattern of fi sh in aquatic environments, while studies on the assessment of the biomass of submerged macrophytes in the littoral zones are still rare. In the present study we provide fi rst results showing that indeed this method is a useful tool to estimate the aq...

A s the article on CC-WaterS (page 15) in this issue reports, numerous scientists and practitioners are currently devising strategies for breaking the coarse-meshed IPCC climate forecasts down into subsets to filter out meaningful climate forecasts for individual regions and sectors. The contribution for Euro-pe (covered by Work Package 2 Impacts)...

Mitterwasser (Danube floodplain lake, Austria) can be considered as a hydrologically stable stream as it is protected from natural flooding by damming. Local hydraulic factors such as water velocity, substrate type and depth are likely to primarily determine the establishment of macrophyte assemblages in streams with low disturbance frequencies. En...

The UNESCO Biosphere Reserve Lobau (Austria), established in 1977 within the city limits of Vienna, is part of the Danube National Park and one of the ecologically richest parts of the Danube River Corridor. Hardly noticed by diverging stakeholder interests the smaller aquatic habitats in the floodplain area are acutely threatened by wetland ageing...

This book contains 15 chapters dealing with the integration of ecology with hydrology at the river basin scale. The patterns and processes in the catchment including nutrients, lotic vegetation and aquatic faunal processes are covered. In addition, the benefits and risks of ecological modelling to water management and nutrient budget modelling for...

This book contains 15 chapters dealing with the integration of ecology with hydrology at the river basin scale. The patterns and processes in the catchment including nutrients, lotic vegetation and aquatic faunal processes are covered. In addition, the benefits and risks of ecological modelling to water management and nutrient budget modelling for...

Ecological compensation structures in the reservoir of the Freudenau hydro-electric power plant (River Danube, Vienna, Austria) developed into habitats dominated by aquatic macrophytes. Ecological functioning of the macrophytes is documented by their attractiveness to several fish guilds, including the rheophilic group and by their ability to restr...

The Krka River is a lowland karstic watercourse with an extended underground hydrological net. Travertine cascades, blocks and dams in the riverbed influence the river flow and depth, creating a variety of habitats. The watershed landscape is a mosaic of agricultural and natural patches with some urban areas. Macrophyte and habitat survey was made...

The quality of the aquatic environment and macrophytes were surveyed in the case of the remarkable karstic river Ljubljanica s. lat. (Slovenia). It consists of seven intermittent and permanent surface watercourses, connected by groundwater flows. We assessed 11 parameters describing the land use beyond the riparian zone, the structure of the ripari...

Klátovské rameno is the lowland slow-flowing groundwater feed eutrophic tributary of the Malý Dunaj River (Danube Plain), where was our study of temporal changes of aquatic macrophytes vegetation realised in 1999 and 2005. For survey of aquatic vascular macrophytes was used the Kohlers method (Janauer 2003), which is compliant with European standar...

This study evaluates the impact of the 2002 extreme flood on the aquatic vegetation in a former Danube side channel called "Mitterwasser" in Linz (Upper Austria). The Mitterwasser is connected to the main river channel only at its lower end and is influenced by backflow of Danube River water in periods of higher discharge. From 2001 to 2003 the mac...

Floodplain lakes are one of the most essential habitats for aquatic macrophytes in the modern cultural landscape. Their maintenance and support calls for ecohydrological strategies, as river development, enhanced flood control and other stakeholder interests may have negative impact on the present oxbow ecosystems. Three examples are given to prese...

The Lobau is a floodplain within the city limits of Vienna, Austria, and is situated on the left side of the Danube River. Since the regulation of the Danube between 1830 and 1880, the Lobau floodplain is disconnected from the main channel. Lateral embankments along the main channel enhanced the aggradation of floodplain water bodies and thus, a fu...

MacrophytesAlgaeAcknowledgementsReferences

Introduction In the course of several projects (Multifunctional Integrated Study Danube / Corridor and Catchment (MIDCC), Developing an electronic database of the macrophytes in Bulgaria, Red Lists of Bulgarian Vascular Plants and Fungi project, and Red Data Book of Bulgaria (new edition project), the macrophytes were studied in the Bulgarian stret...

The backwater system of the Danube in Linz (Upper Austria) is cut off from inundations by damming and impoundment and receives only backflow from the main river channel. Several mainly lentic water bodies remain as part of the local backwater system and house a number of endangered aquatic species. This study predicts the long-term change in macrop...

Vienna is an urban complex of about 1.5 milion people. The entire urban water management drinking water supply, sewage collection and treatment, flood control and the condition of the Danube River Wetlands-is highly functional. Internal co-operation between administration units concerned with different aspects of water management provides the basis...