The intensive utilization of tropical inland water bodies for multiple and sometimes competing ac... more The intensive utilization of tropical inland water bodies for multiple and sometimes competing activities underlines the necessity for their integrated and holistic co-management. This paper presents our synthesis on lake and reservoir fisheries in South and Southeast Asia as social-ecological systems, based on a synopsis of our research findings from a previous EUfunded research programme in Sri Lanka, Thailand and the Philippines (FISHSTRAT project). The paper attempts to merge our results with recent developments in research, policy and practice. We explore the effects of the main external and internal control mechanisms of the trophic state and pinpoint to the high production potential of traditionally unexploited small indigenous fish species. The limitations of conventional centralized management systems highlight the importance of introducing transdisciplinary approaches which integrate limnology, fish ecology and fisheries with the interests of other resource using stakeholders and decision makers in order to develop locally appropriate co-management strategies for sustainable aquatic resource use.
The chironomid communities of two gravel banks in the free-flowing section of the River Danube we... more The chironomid communities of two gravel banks in the free-flowing section of the River Danube were investigated from May to August 1994. The two sites differed significantly in grain size compo sition, current velocity, chironomid abundance and species richness. Seventy-four species of larval chironomids could be identified, most of them belonging to the subfamily Orthocladiinae. Sampling sites were characterized through an index that incorporates duration and intensity of dessication. This index is considered to express the level of disturbance. Chironomid densities were negatively correlated to index values. Species richness and diversity were highest at intermediate values as predicted by ecological theory. Evenness was positively related to the index, suggesting dominance of a few species in undisturbed, permanently flooded sites.
ABSTRACT The physical degradation of large regulated rivers in Europe and North America and the n... more ABSTRACT The physical degradation of large regulated rivers in Europe and North America and the need for rehabilitation have become issues since the 1980s. Over the past years we have greatly increased our understanding of the ecological functioning of natural rivers, evaluated the ecological impacts of river regulation, and established various approaches for river rehabilitation and restoration. Complete restoration of large rivers may be a utopian idea because of the manifold functions they serve. It is not surprising, therefore, that rehabilitation attempts so far have only recovered stretches or certain features of rivers. The steps to be taken now are to share our expertise on river functioning, river management and rehabilitation, and to put this expertise into practice.
Current Opinion in Environmental Sustainability, 2015
This paper highlights the challenges of distilling generalizable principles and guidelines for su... more This paper highlights the challenges of distilling generalizable principles and guidelines for sustainable co-management arrangements and demonstrating the practical impact of the underlying research. We explore the complexities of multicountry, socio-ecological research and address the challenges of moving beyond pure research to engage with the sciencepolicy-practice interfaces. Growing demand for such applied research by official funding agencies is linked to the requirements of policy relevance and 'research impact'. Successful applied research requires ongoing user engagement throughout a project, which is often hard to achieve, especially when diverse stakeholders have sharply different power, knowledge and interests. The arguments are exemplified by our personal experience on such a complex project. Clear impact agendas could be useful for strengthening efforts to achieve transdisciplinarity but research applications should not be penalised on account of inherent potential uncertainties and risks.
Riparian zones, floodplains and rivermarginal wetlands are among the most endangered freshwater ... more Riparian zones, floodplains and rivermarginal wetlands are among the most endangered freshwater ecosystems worldwide nowadays (Brinson & Malvarez 2002, Malmqvist & Rundle 2002). Most wetlands within urban regions have already been converted to terrestrial ecosystems, ...
Along the Upper Danube, almost all former floodplain areas have been lost due to river regulation... more Along the Upper Danube, almost all former floodplain areas have been lost due to river regulation, large-scale land-use changes, and terrestrialization processes. In the Lobau floodplain near the City of Vienna, ongoing terrestrialization leads to a dramatic loss of aquatic and semiaquatic habitats. Although the ecological values of the remaining floodplain area, such as high productivity and high biodiversity, are widely acknowledged, the implementation of restoration measures is difficult. In urban environments such as the Lobau, planning and decision-making for floodplain restoration inevitably involves trade-offs, uncertainties, and conflicting objectives and value judgments. Beyond ecological values, the main socioeconomic aspects are flood control, drinking water supply for Vienna, and recreation. The aim of this chapter is to present the current ecological situation and the major development tendencies of the Lobau floodplain and to show the effects of potential management measures on the ecological situation.
Despite the prospering results emerging from some recent works on Iranian amphipod fauna, contine... more Despite the prospering results emerging from some recent works on Iranian amphipod fauna, continental waters in the south-east edges of the Zagros Mountain ranges had not been investigated for gammarids before. This paper introduces two new epigean species, G. shirazinus and G. loeffleri, distributed in many running waters of four catchment areas in a broad region in the south of Iran. The most important ecological features of the habitats of these species in comparison with previously studied gammarids are higher water temperature and salinity, and lower dissolved oxygen in their habitats, coinciding with decreasing elevation. A comparison of the ultra-structure of the cuticle of the head capsule by scanning electron microscopy between these two new species, and some other species is given. A detailed species description is provided. In addition, the geographical and ecological range of the new species is discussed.
Research on tropical streams has progressed markedly over the last decade. However, many aspects ... more Research on tropical streams has progressed markedly over the last decade. However, many aspects of biodiversity and functional processes require more detailed attention. The rivers and streams of the Piedras Blancas National Park in southwestern Costa Rica provide a unique opportunity to study near-pristine rainforest streams and tropical freshwater ecology. One of the primary objectives of the study was to provide a survey of the river network within the Río Esquinas catchment. Rivers were analysed with regard to abiotic parameters such as morphology, hydrology, hydrochemistry, sedimentology, and to biotic parameters such as canopy cover by the riparian vegetation during the dry and rainy season in 2004. Surveys were carried out on nine streams and rivers, ranging from 1 st order to 4 th order, which empty into the Golfo Dulce at the Pacific Ocean. The paper discusses differences between sites according to geology and the seasonal hydrological characteristics of running waters within the catchment. The hydrochemical stream signatures indicate different geological sources within the Río Esquinas catchment. High water temperatures (> 25°C) are a permanent feature. The streams and rivers exhibit a high annual variation in discharge, turbidity and hydrochemistry as a result of seasonal rainfall. The mean discharge during the rainy season can be 3 times higher than in the dry season. Detailed morphometric-hydrological measurements at the Quebrada Negra, a 1 st order stream, show a clear picture of a highly heterogeneous, dynamic and unregulated stream course with a sequence of pool and riffle sections. Rapid water level fluctuations caused by heavy rains are typical. The abundant riparian vegetation is of major significance for the structure and function of the stream ecosystem. The food web structure and trophic interactions of neotropical streams are analysed, taking the results of the Quebrada Negra as an example.
The intensive utilization of tropical inland water bodies for multiple and sometimes competing ac... more The intensive utilization of tropical inland water bodies for multiple and sometimes competing activities underlines the necessity for their integrated and holistic co-management. This paper presents our synthesis on lake and reservoir fisheries in South and Southeast Asia as social-ecological systems, based on a synopsis of our research findings from a previous EUfunded research programme in Sri Lanka, Thailand and the Philippines (FISHSTRAT project). The paper attempts to merge our results with recent developments in research, policy and practice. We explore the effects of the main external and internal control mechanisms of the trophic state and pinpoint to the high production potential of traditionally unexploited small indigenous fish species. The limitations of conventional centralized management systems highlight the importance of introducing transdisciplinary approaches which integrate limnology, fish ecology and fisheries with the interests of other resource using stakeholders and decision makers in order to develop locally appropriate co-management strategies for sustainable aquatic resource use.
The chironomid communities of two gravel banks in the free-flowing section of the River Danube we... more The chironomid communities of two gravel banks in the free-flowing section of the River Danube were investigated from May to August 1994. The two sites differed significantly in grain size compo sition, current velocity, chironomid abundance and species richness. Seventy-four species of larval chironomids could be identified, most of them belonging to the subfamily Orthocladiinae. Sampling sites were characterized through an index that incorporates duration and intensity of dessication. This index is considered to express the level of disturbance. Chironomid densities were negatively correlated to index values. Species richness and diversity were highest at intermediate values as predicted by ecological theory. Evenness was positively related to the index, suggesting dominance of a few species in undisturbed, permanently flooded sites.
ABSTRACT The physical degradation of large regulated rivers in Europe and North America and the n... more ABSTRACT The physical degradation of large regulated rivers in Europe and North America and the need for rehabilitation have become issues since the 1980s. Over the past years we have greatly increased our understanding of the ecological functioning of natural rivers, evaluated the ecological impacts of river regulation, and established various approaches for river rehabilitation and restoration. Complete restoration of large rivers may be a utopian idea because of the manifold functions they serve. It is not surprising, therefore, that rehabilitation attempts so far have only recovered stretches or certain features of rivers. The steps to be taken now are to share our expertise on river functioning, river management and rehabilitation, and to put this expertise into practice.
Current Opinion in Environmental Sustainability, 2015
This paper highlights the challenges of distilling generalizable principles and guidelines for su... more This paper highlights the challenges of distilling generalizable principles and guidelines for sustainable co-management arrangements and demonstrating the practical impact of the underlying research. We explore the complexities of multicountry, socio-ecological research and address the challenges of moving beyond pure research to engage with the sciencepolicy-practice interfaces. Growing demand for such applied research by official funding agencies is linked to the requirements of policy relevance and 'research impact'. Successful applied research requires ongoing user engagement throughout a project, which is often hard to achieve, especially when diverse stakeholders have sharply different power, knowledge and interests. The arguments are exemplified by our personal experience on such a complex project. Clear impact agendas could be useful for strengthening efforts to achieve transdisciplinarity but research applications should not be penalised on account of inherent potential uncertainties and risks.
Riparian zones, floodplains and rivermarginal wetlands are among the most endangered freshwater ... more Riparian zones, floodplains and rivermarginal wetlands are among the most endangered freshwater ecosystems worldwide nowadays (Brinson & Malvarez 2002, Malmqvist & Rundle 2002). Most wetlands within urban regions have already been converted to terrestrial ecosystems, ...
Along the Upper Danube, almost all former floodplain areas have been lost due to river regulation... more Along the Upper Danube, almost all former floodplain areas have been lost due to river regulation, large-scale land-use changes, and terrestrialization processes. In the Lobau floodplain near the City of Vienna, ongoing terrestrialization leads to a dramatic loss of aquatic and semiaquatic habitats. Although the ecological values of the remaining floodplain area, such as high productivity and high biodiversity, are widely acknowledged, the implementation of restoration measures is difficult. In urban environments such as the Lobau, planning and decision-making for floodplain restoration inevitably involves trade-offs, uncertainties, and conflicting objectives and value judgments. Beyond ecological values, the main socioeconomic aspects are flood control, drinking water supply for Vienna, and recreation. The aim of this chapter is to present the current ecological situation and the major development tendencies of the Lobau floodplain and to show the effects of potential management measures on the ecological situation.
Despite the prospering results emerging from some recent works on Iranian amphipod fauna, contine... more Despite the prospering results emerging from some recent works on Iranian amphipod fauna, continental waters in the south-east edges of the Zagros Mountain ranges had not been investigated for gammarids before. This paper introduces two new epigean species, G. shirazinus and G. loeffleri, distributed in many running waters of four catchment areas in a broad region in the south of Iran. The most important ecological features of the habitats of these species in comparison with previously studied gammarids are higher water temperature and salinity, and lower dissolved oxygen in their habitats, coinciding with decreasing elevation. A comparison of the ultra-structure of the cuticle of the head capsule by scanning electron microscopy between these two new species, and some other species is given. A detailed species description is provided. In addition, the geographical and ecological range of the new species is discussed.
Research on tropical streams has progressed markedly over the last decade. However, many aspects ... more Research on tropical streams has progressed markedly over the last decade. However, many aspects of biodiversity and functional processes require more detailed attention. The rivers and streams of the Piedras Blancas National Park in southwestern Costa Rica provide a unique opportunity to study near-pristine rainforest streams and tropical freshwater ecology. One of the primary objectives of the study was to provide a survey of the river network within the Río Esquinas catchment. Rivers were analysed with regard to abiotic parameters such as morphology, hydrology, hydrochemistry, sedimentology, and to biotic parameters such as canopy cover by the riparian vegetation during the dry and rainy season in 2004. Surveys were carried out on nine streams and rivers, ranging from 1 st order to 4 th order, which empty into the Golfo Dulce at the Pacific Ocean. The paper discusses differences between sites according to geology and the seasonal hydrological characteristics of running waters within the catchment. The hydrochemical stream signatures indicate different geological sources within the Río Esquinas catchment. High water temperatures (> 25°C) are a permanent feature. The streams and rivers exhibit a high annual variation in discharge, turbidity and hydrochemistry as a result of seasonal rainfall. The mean discharge during the rainy season can be 3 times higher than in the dry season. Detailed morphometric-hydrological measurements at the Quebrada Negra, a 1 st order stream, show a clear picture of a highly heterogeneous, dynamic and unregulated stream course with a sequence of pool and riffle sections. Rapid water level fluctuations caused by heavy rains are typical. The abundant riparian vegetation is of major significance for the structure and function of the stream ecosystem. The food web structure and trophic interactions of neotropical streams are analysed, taking the results of the Quebrada Negra as an example.
Uploads
Papers by Fritz Schiemer