Autor(es):
Teixeira, Heliana Lilita Gonçalves 
Data: 2010
Identificador Persistente: http://hdl.handle.net/10316/13894
Origem: Estudo Geral - Universidade de Coimbra
Detalhes do Documento
Benthic macroinvertebrates as ecological indicators for estuarine and coastal e...
Descrição
The aim of the research work presented in this thesis is to be a contribution to the field of ecological assessment in coastal and transitional ecosystems. The main goals were: a) to present a method for the assessment of the ecological status of benthic macroinvertebrate communities in Portuguese transitional waters that would meet the requirements of the European Water Framework Directive (WFD); and b) to propose alternatives to harmonize ecological assessments, namely those based on benthic macroinvertebrate, across wide geographic scales. Chapters I, II and III describe the steps to attain the first major goal. For this purpose, it was used data from the Mondego estuary in Portugal, where biological and environmental data had been routinely collected from 1990 to 2006. Since the 1980’s this system has been harassed by anthropogenic pressures commonly observed in coastal environments worldwide, such as eutrophication and physical disturbances that led to hydromorphological changes of the system properties. An evident ecological quality decrease in the estuary triggered the implementation of mitigation measures in the last 12 years, enabling its recovery. Therefore, the Mondego estuary provided an important field lab to test a battery of indices selected for evaluating the ecological status in transitional waters under the scope of the WFD. Chapter I describes how habitat mapping allowed setting natural expectations for biological communities’ distribution along estuarine gradients. Environmental data, such as salinity, sediment grain size composition and organic matter content, from recent years (2002 to 2005, covering all seasons), and relevant for structuring subtidal benthic invertebrate communities, were used to identify six distinct zones within the Mondego estuary (ANOSIM and Principal Component Analysis ‐ PCA, PRIMER Software). The observed environmental trends significantly reflected the patterns of distribution of the invertebrate communities (BIOENV and ANOSIM, PRIMER Software), and allowed accounting for the influence of natural gradients in the performance of ecological assessments tools. In Chapter II, three ecological indices (Margalef index, Shannon‐Wiener index and AZTI’s Marine Biotic Index ‐ AMBI), selected to meet the EU WFD requirements, were evaluated for their potential to detect impaired benthic invertebrate communities and their subsequent recovery. To attain this goal, the indices were tested in three periods (Springs of 1990/1992, 2000/2002 and 2005/2006) of distinct pressures intensity in the Mondego estuary. The trends detected by the indices (PERMANOVA) concurred with the history of disturbance of the system, responding both to different types of impacts and to mitigation measures undertaken. This allowed defining approximate reference conditions for the indices proposed that would reflect a quality improvement in the benthic invertebrate compartment, while accounting for the natural gradients acting upon these communities along the system. Chapter III describes the performance of the BAT – Benthic Assessment Tool, a multimetric tool sensu the EU WFD guidelines, which consists of the three indices previously selected for the Mondego estuary merged into a single value – the Ecological Quality Ratio (EQR). This EQR is obtained after a Factor Analysis (PCA extraction method, Statgraphics Software) and Euclidean distance projection, using the reference conditions proposed in Chapter II to limit the scale of EQR from 0 to 1, as described in Bald et al. (2005). The method was tested against the effects of anthropogenic disturbance using eight years (Springs between 1990 to 2006) of subtidal benthic invertebrate data from the Mondego estuary. Although the BAT could capture the ecological decline and recovery of the system as reflected by the benthic invertebrates, the indices within the mutlimetric tool were not contributing equally to the final classification. Constraints such as the typical abundance of tolerant species in estuarine ecosystems and the ecological classification of key species in the Mondego estuary have weakened mainly the performance of the AMBI. Chapters IV and V exemplify and propose distinct ways to intercalibrate ecological assessments across wide geographic scales. Chapter IV explains the process to adapt the European developed index, AMBI, to a new geography. With macroinvertebrate data from Southern California marine bays, the index was calibrated to the new habitat using local taxonomic expertise to classify local species into the ecological groups used by the AMBI. Then, taking the ranking and classification of samples, AMBI performance was validated against the local Benthic Response Index (BRI) and also using the Professional Judgement of benthic ecologists. The best correlation between the AMBI results and those of the BRI (n= 685: r= 0.70; Kappa: Moderate agreement for samples classification) was obtained applying AMBI based on a mixture of local and previous expertise regarding species ecological classification, and including a weighting factor for abundance data. As for the best agreement of the AMBI with Expert Judgement (n= 21: r= 0.93; Kappa: Very Good agreement for samples classification), it was reached using local expertise criteria for the classification of species ecological strategy, for non‐transformed abundance data. The AMBI presented however less discriminatory power than Expert judgement for the classification of samples. The study revealed that a significant part of the disagreements between the two indices’ assessments resulted from the approaches followed by each to classify species according to their ecological strategies. Chapter V proposes an approach that uses the consensus among expert best professional judgement (BPJ) to establish a common scaling for benthic ecological assessments. Sixteen benthic ecologists from four regions in Europe and USA were provided macroinvertebrates species‐abundance data for twelve sites per region, to rank from best to worst and classify into four categories. Site rankings were highly correlated among experts regardless of whether they were assessing samples from their home region. There was also good agreement on condition category, though agreement was better for samples at extremes of the disturbance gradient. The absence of regional bias and the agreement obtained suggest that expert judgment is a viable means for establishing a uniform scale to calibrate indices consistently across geographic regions. Tese de doutoramento em Biologia (Ecologia) apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra PhD grant attributed to Heliana Teixeira (SFRH/BD/24430/2005)
The aim of the research work presented in this thesis is to be a contribution to the field of ecological assessment in coastal and transitional ecosystems. The main goals were: a) to present a method for the assessment of the ecological status of benthic macroinvertebrate communities in Portuguese transitional waters that would meet the requirements of the European Water Framework Directive (WFD); and b) to propose alternatives to harmonize ecological assessments, namely those based on benthic macroinvertebrate, across wide geographic scales. Chapters I, II and III describe the steps to attain the first major goal. For this purpose, it was used data from the Mondego estuary in Portugal, where biological and environmental data had been routinely collected from 1990 to 2006. Since the 1980’s this system has been harassed by anthropogenic pressures commonly observed in coastal environments worldwide, such as eutrophication and physical disturbances that led to hydromorphological changes of the system properties. An evident ecological quality decrease in the estuary triggered the implementation of mitigation measures in the last 12 years, enabling its recovery. Therefore, the Mondego estuary provided an important field lab to test a battery of indices selected for evaluating the ecological status in transitional waters under the scope of the WFD. Chapter I describes how habitat mapping allowed setting natural expectations for biological communities’ distribution along estuarine gradients. Environmental data, such as salinity, sediment grain size composition and organic matter content, from recent years (2002 to 2005, covering all seasons), and relevant for structuring subtidal benthic invertebrate communities, were used to identify six distinct zones within the Mondego estuary (ANOSIM and Principal Component Analysis ‐ PCA, PRIMER Software). The observed environmental trends significantly reflected the patterns of distribution of the invertebrate communities (BIOENV and ANOSIM, PRIMER Software), and allowed accounting for the influence of natural gradients in the performance of ecological assessments tools. In Chapter II, three ecological indices (Margalef index, Shannon‐Wiener index and AZTI’s Marine Biotic Index ‐ AMBI), selected to meet the EU WFD requirements, were evaluated for their potential to detect impaired benthic invertebrate communities and their subsequent recovery. To attain this goal, the indices were tested in three periods (Springs of 1990/1992, 2000/2002 and 2005/2006) of distinct pressures intensity in the Mondego estuary. The trends detected by the indices (PERMANOVA) concurred with the history of disturbance of the system, responding both to different types of impacts and to mitigation measures undertaken. This allowed defining approximate reference conditions for the indices proposed that would reflect a quality improvement in the benthic invertebrate compartment, while accounting for the natural gradients acting upon these communities along the system. Chapter III describes the performance of the BAT – Benthic Assessment Tool, a multimetric tool sensu the EU WFD guidelines, which consists of the three indices previously selected for the Mondego estuary merged into a single value – the Ecological Quality Ratio (EQR). This EQR is obtained after a Factor Analysis (PCA extraction method, Statgraphics Software) and Euclidean distance projection, using the reference conditions proposed in Chapter II to limit the scale of EQR from 0 to 1, as described in Bald et al. (2005). The method was tested against the effects of anthropogenic disturbance using eight years (Springs between 1990 to 2006) of subtidal benthic invertebrate data from the Mondego estuary. Although the BAT could capture the ecological decline and recovery of the system as reflected by the benthic invertebrates, the indices within the mutlimetric tool were not contributing equally to the final classification. Constraints such as the typical abundance of tolerant species in estuarine ecosystems and the ecological classification of key species in the Mondego estuary have weakened mainly the performance of the AMBI. Chapters IV and V exemplify and propose distinct ways to intercalibrate ecological assessments across wide geographic scales. Chapter IV explains the process to adapt the European developed index, AMBI, to a new geography. With macroinvertebrate data from Southern California marine bays, the index was calibrated to the new habitat using local taxonomic expertise to classify local species into the ecological groups used by the AMBI. Then, taking the ranking and classification of samples, AMBI performance was validated against the local Benthic Response Index (BRI) and also using the Professional Judgement of benthic ecologists. The best correlation between the AMBI results and those of the BRI (n= 685: r= 0.70; Kappa: Moderate agreement for samples classification) was obtained applying AMBI based on a mixture of local and previous expertise regarding species ecological classification, and including a weighting factor for abundance data. As for the best agreement of the AMBI with Expert Judgement (n= 21: r= 0.93; Kappa: Very Good agreement for samples classification), it was reached using local expertise criteria for the classification of species ecological strategy, for non‐transformed abundance data. The AMBI presented however less discriminatory power than Expert judgement for the classification of samples. The study revealed that a significant part of the disagreements between the two indices’ assessments resulted from the approaches followed by each to classify species according to their ecological strategies. Chapter V proposes an approach that uses the consensus among expert best professional judgement (BPJ) to establish a common scaling for benthic ecological assessments. Sixteen benthic ecologists from four regions in Europe and USA were provided macroinvertebrates species‐abundance data for twelve sites per region, to rank from best to worst and classify into four categories. Site rankings were highly correlated among experts regardless of whether they were assessing samples from their home region. There was also good agreement on condition category, though agreement was better for samples at extremes of the disturbance gradient. The absence of regional bias and the agreement obtained suggest that expert judgment is a viable means for establishing a uniform scale to calibrate indices consistently across geographic regions. Tese de doutoramento em Biologia (Ecologia) apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra PhD grant attributed to Heliana Teixeira (SFRH/BD/24430/2005)
Tipo de Documento
Tese de Doutoramento
Idioma Inglês
Idioma Inglês
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