The use of benthic communities in environmental health assessment

Quality classification of water bodies commonly hinges upon the results of biotic indices. Biotic indices should reliably detect environmental change caused by anthropogenic stress; distinguish between different levels of disturbance; and be applicable in different areas. This study assesses current methods used in the assessment of benthic ecosystem health in transitional and coastal waters. Specifically, this study considers the performance of macrozoobenthos based biotic and diversity indices. Data utilised in the assessment covered a range of sites and environmental gradients including long term monitoring sites in Scotland; sites impacted by fish farms, organic waste discharge, and chemical effluent; estuarine sites; and sites from Galway Bay, Ireland, one of which was impacted by river discharge. Currently used indices of environmental status are based mainly on structural ecosystem properties and may not encompass all aspects of ecosystem health, such as functioning. Structural and functional based assessment methods were evaluated by comparing the performance of a range of standard benthic abundance indices and approaches focussing on intrinsic biological characteristics. Indices did not perform consistently in response to different types of impact – organic, chemical and physical, indicating some indices are unsuitable for the detection of multiple stressors. Index quality classifications agreed best in the most impacted sites but performed unpredictably in moderate conditions. Variability of indices increased as disturbance increased, decreasing the statistical certainty and confidence in the index values. Structural indices were found to be more variable than functional indices but the sensitivity of functional indices to anthropogenic disturbance needs further testing to determine whether they are able to detect low level disturbance. Functional indices may not be advantageous in regular monitoring over traditional methods but may provide a more informative assessment of ecosystem health. Use of biological traits may also give an indication of the type or cause of disturbance. Classification of moderate-good conditions using benthic indices is particularly ambiguous and distinguishing natural from anthropogenic disturbance remains one of the biggest challenges. The results indicate that complementarity of approaches is important in the assessment of quality of coastal and transitional benthic aquatic systems.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The use of benthic communities in environmental health assessment

Quality classification of water bodies commonly hinges upon the results of biotic indices. Biotic indices should reliably detect environmental change caused by anthropogenic stress; distinguish between different levels of disturbance; and be applicable in different areas. This study assesses current methods used in the assessment of benthic ecosystem health in transitional and coastal waters. Specifically, this study considers the performance of macrozoobenthos based biotic and diversity indices. Data utilised in the assessment covered a range of sites and environmental gradients including long term monitoring sites in Scotland; sites impacted by fish farms, organic waste discharge, and chemical effluent; estuarine sites; and sites from Galway Bay, Ireland, one of which was impacted by river discharge. Currently used indices of environmental status are based mainly on structural ecosystem properties and may not encompass all aspects of ecosystem health, such as functioning. Structural and functional based assessment methods were evaluated by comparing the performance of a range of standard benthic abundance indices and approaches focussing on intrinsic biological characteristics.Indices did not perform consistently in response to different types of impact – organic, chemical and physical, indicating some indices are unsuitable for the detection of multiple stressors. Index quality classifications agreed best in the most impacted sites but performed unpredictably in moderate conditions. Variability of indices increased as disturbance increased, decreasing the statistical certainty and confidence in the index values. Structural indices were found to be more variable than functional indices but the sensitivity of functional indices to anthropogenic disturbance needs further testing to determine whether they are able to detect low level disturbance. Functional indices may not be advantageous in regular monitoring over traditional methods but may provide a more informative assessment of ecosystem health. Use of biological traits may also give an indication of the type or cause of disturbance. Classification of moderate-good conditions using benthic indices is particularly ambiguous and distinguishing natural from anthropogenic disturbance remains one of the biggest challenges. The results indicate that complementarity of approaches is important in the assessment of quality of coastal and transitional benthic aquatic systems

Response of a marine benthic invertebrate community and biotic indices to organic enrichment from sewage disposal

Nutrient enrichment is a significant cause of ecosystem change in coastal habitats worldwide. This study focuses on the change in a benthic macroinvertebrate community and environmental quality as assessed through different biotic indices following the construction of a sewage outfall pipe in the west of Scotland, from first implementation to seven years after operation of the pipe. Benthic macroinvertebrates are an important part of marine ecosystems because they mediate ecosystem processes and functions, are a key part of food webs and they provide many ecosystem services. Results indicated a clear change in benthic communities over time with an increase in species richness and changes to benthic community composition (specifically feeding type, bioturbation mode and ecological group) towards those indicative of organic enrichment. No clear spatial zonation was observed because organic carbon content increased over the entire area. According to a suite of benthic indices calculated, some negative changes were detectable following the start of sewage disposal, but largely negative community changes, and a change from 'good' to 'moderate' quality, only occurred seven years after implementation. The increase in species richness in response to increasing disturbance reduced the utility of a multi-metric index, the Infaunal Quality Index, which, instead of amplifying the signal of negative impact, dampened it. We suggest that any change in communities, regardless of direction, should be heeded, and species richness is a particularly sensitive and early warning indicator for this, but a suite of approaches is required to understand benthic community changes

Structural and functional indices show similar performance in marine ecosystem quality assessment

Reliable ecosystem quality assessment of marine environments is increasingly important due to mounting pressures attributable to human activities. Biotic indices are widely used in studies to describe communities and indicate the ecological state of systems. This study focuses on benthic macroinvertebrate-based biotic indices for the assessment of ecosystem health. Indices used in ecosystem health assessment in the marine environment have mainly focussed on measuring structural components of the system while more recently the measurement of functional components has been highlighted. In this study the performance of traditional diversity indices based on structural components of benthic macroinvertebrate communities, indices developed for the EU Water Framework Directive, and indices which are based on functional biological traits of species were compared. The results indicated that while functional indices may provide a more detailed assessment of the benthic communities than structural indices, the overall outcome is broadly similar for both types of indices. This suggests measurement of functional indices may be unnecessary for routine monitoring purposes, although they may have value in revealing more specific aspects of change in a system. © 2014 Elsevier Ltd.AB - Reliable ecosystem quality assessment of marine environments is increasingly important due to mounting pressures attributable to human activities. Biotic indices are widely used in studies to describe communities and indicate the ecological state of systems. This study focuses on benthic macroinvertebrate-based biotic indices for the assessment of ecosystem health. Indices used in ecosystem health assessment in the marine environment have mainly focussed on measuring structural components of the system while more recently the measurement of functional components has been highlighted. In this study the performance of traditional diversity indices based on structural components of benthic macroinvertebrate communities, indices developed for the EU Water Framework Directive, and indices which are based on functional biological traits of species were compared. The results indicated that while functional indices may provide a more detailed assessment of the benthic communities than structural indices, the overall outcome is broadly similar for both types of indices. This suggests measurement of functional indices may be unnecessary for routine monitoring purposes, although they may have value in revealing more specific aspects of change in a system

Assessing the capacity of European regional seas to supply ecosystem services using marine status assessments

In this paper we describe work that progresses the understanding of socio-ecological systems from the perspective of exploring how the supply of ecosystem services might vary with changes in the state of ecosystem components. We developed and tested a new assessment approach (concept, framework and methodology) to assess the capacity of marine ecosystems to supply services, which could be carried out using available policy-reported assessment information on marine biodiversity and ecosystem status. The starting point was an assessment that drew on an understanding of ecosystem state-service relationships, and that was extended to incorporate operational, policy-relevant ecosystem assessment information at European regional sea scales in response to the requirements of the EU Biodiversity Strategy to 2020. The assessment consists of three key steps: (1) identifying all the instances where a marine ecosystem component can potentially contribute to the supply of a marine ecosystem service; (2) developing a critical pathway analysis to identify the major ecosystem component(s) contributing to the supply of a given service; (3) interpreting available information on the state and trends of these major contributing components with knowledge of the ecosystem state-service relationship, to assess the ecosystem's capacity for service supply and its direction of change. The assessment provides a common approach that can be applied across marine regions, and in data rich or data poor situations. This approach captures the sustainability of ecosystem service supply capacity through retaining the connection with the state of the ecosystem and can help to inform management decisions and track the effectiveness of environmental policies.</p