Systematic processes of land use/land cover change to identify relevant driving forces: Implications on water quality

Land use and land cover (LULC) are driving forces that potentially exert pressures on water bodies, which are most commonly quantified by simply obtained aggregated data. However, this is insufficient to detect the drivers that arise from the landscape change itself. To achieve this objective one must distinguish between random and systematic transitions and identify the transitions that show strong signals of change, since these will make it possible to identify the transitions that have evolved due to population growth, industrial expansion and/or changes in land management policies. Our goal is to describe a method to characterize driving forces both from LULC and dominant LULC changes, recognizing that the presence of certain LULC classes as well as the processes of transition to other uses are both sources of stress with potential effects on the condition of water bodies. This paper first quantifies the driving forces from LULC and also from processes of LULC change for three nested regions within the Mondego river basin in 1990, 2000 and 2006. It then discusses the implications for the environmental water body condition and management policies. The fingerprint left on the landscape by some of the dominant changes found, such as urbanization and industrial expansion, is, as expected, low due to their proportion in the geographic regions under study, yet their magnitude of change and consistency reveal strong signals of change regarding the pressures acting in the system. Assessing dominant LULC changes is vital for a comprehensive study of driving forces with potential impacts on water condition.The present study was carried using means provided by the research projects RECONNECT (PTDC/MAR/64627/2006), WISER (FP7-ENV-2008-226273), and 3M-RECITAL (LTER/BIA-BEC/0019/ 2009). Additionally, it benefited from two grants attributed by the FCT (Portuguese National Science Foundation): SFRH/BD/74804/ 2010 and SFRH/BPD/82127/2011

Benthic macroinvertebrates as ecological indicators for estuarine and coastal ecosystems : assessment and intercalibration

Tese de doutoramento em Biologia (Ecologia) apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraThe 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.PhD grant attributed to Heliana Teixeira (SFRH/BD/24430/2005

Composición de grupos tróficos funcionales en una comunidad macrobentónica submareal a lo largo de un gradiente de profundidad

The feeding guild composition of a macrobenthic community from southern Portugal was studied along a depth gradient (1.3 to 32 m). This gradient comprised shallow areas with severe physical stress and deeper areas with no significant hydrodynamic impact at the seafloor. The main goal was to determine the influence of the spatial and temporal differences of the hydrodynamic impact at the seafloor on the feeding guild composition of the macrobenthic community. The feeding guild composition changed gradually with depth, which reflects the differences in the hydrodynamics impact at the seafloor. Herbivores and sand-lickers dominated at the shallowest depths with fine sands, which correlated with higher levels of primary production. Scavengers were also distributed in the shallow areas, which was associated with the lower predation impact. Suspension feeders, in accordance with their physiological requirements, were distributed in coarser sands subjected to a physical impact. Carnivores, surface deposit feeders and sub-surface deposit feeders were distributed mainly below 8 m depth, where there was no significant impact from the wave climate. Carnivores were associated with coarser sands and were mainly small polychaetes and nemerteans. Sub-surface and surface deposit feeders were more abundant in the deepest areas of the depth gradient with fine sands and mud deposits with higher organic content. However, surface deposit feeders also occurred at shallower depths. Some seasonal differences related to disturbance impacts were found in the numerical dominance of the feeding guilds.Se han estudiado las categorías tróficas de una comunidad macrobentónica en el sur de Portugal, a lo largo de un gradiente de profundidad (de 1.3 m a 32 m). Este gradiente incluía áreas someras (poco profundas) con un estrés físico severo y áreas más profundas sin impacto hidrodinámico significativo a nivel del fondo marino. El objetivo principal fue determinar la influencia de las diferencias espaciales y temporales del impacto hidrodinámico en el fondo marino sobre la composición de las categorías tróficas de la comunidad macrobentónica. La composición de estas categorías tróficas cambió gradualmente con la profundidad, reflejando las diferencias del impacto hidrodinámico en el lecho marino. Las profundidades más someras, compuestas por arenas finas, estaban dominadas por anfípodos herbívoros y raspadores de arenas, correspondiéndose con elevados niveles de producción primaria. También había en estas áreas someras carnívoros/necrófagos asociados a un menor impacto de predación. Los suspensívoros, fundamentalmente bivalvos, predominaron en zonas con arenas más gruesas y mayor hidrodinamismo, de acuerdo con sus necesidades fisiológicas. Por debajo de los 8 m de profundidad y en zonas donde no se produce impacto del oleaje, dominaban carnívoros, detritívoros de fondo y de sub-fondo. Los carnívoros, asociados a arenas más gruesas, eran principalmente pequeños poliquetos y nemertinos. Los detritívoros de fondo y sub-fondo eran más abundantes en las zonas más profundas del gradiente, donde aparecían arenas finas y depósitos de limo con elevados contenidos en materia orgánica. Sin embargo, también se encontraron detritívoros de fondo en profundidades menores. Se encontraron algunas diferencias en la dominancia numérica de la estructura trófica a lo largo del año, lo que puede estar relacionado con impactos de incidentes en la zona

The importance of habitat-type for defining the reference conditions and the ecological quality status based on benthic invertebrates: the Ria Formosa coastal lagoon (Southern Portugal) case study

Coastal lagoons are complex systems, with considerable habitat heterogeneity and often subject to high temporal dynamics, which constitutes a great challenge for ecological assessment programs. For defining reference conditions for benthic invertebrates, under the EU Water Framework Directive objectives, historical data from the Ria Formosa leaky lagoon (wet surface area of about 105 km2) located in Southern Portugal was used. The influence of habitat features, such as channel depth, sediment type and seagrass cover, on the expression of these biological communities was inferred by analysing subtidal data collected at stations with different environmental characteristics. Such heterogeneity effect was analysed at the community compositional and structural levels, and also for three indices included in a multimetric Benthic Assessment Tool (BAT). This tool for the assessment of ecological status includes the Margalef index, Shannon-Wiener diversity index, and AZTI’s Marine Biotic Index (AMBI). Significant variations associated with environmental features were reflected on specific reference conditions at four habitats in the lagoon. After habitat calibration, the Benthic Assessment Tool (BAT) revealed that, in general and for the period of time covered by this historical data set, the status of the lagoon corresponded to a good ecological condition, which is mainly due to its high water renewal rate. Such classification is in accordance with the majority of studies at the lagoon. However, at punctual sites with human induced high water residence times, significantly lower BAT values were registered. Such community degradation can be associated with physical stress due to salinity increase and to a degradation of water quality, with occurrence of occasional dystrophic crisis, triggered by low water renewal. Habitat 2 differentiation was a crucial step for a correct evaluation of the ecological condition of invertebrate communities across the lagoonal system

Negotiations to implement area-based management tools beyond national jurisdiction: the scientific community’s view

A new international legally-binding instrument, under the United Nations Convention on the Law of the Seas (UNCLOS), for the conservation and sustainable use of marine biodiversity in areas beyond national jurisdiction has recently been agreed on– the BBNJ agreement. Area-based management tools (ABMTs), including marine protected areas (MPAs) have an important role in maintaining biodiversity and ecosystem services in the current context of multiple threats to the ocean and are one of central elements of new instrument. In this work, we assessed the perspective of the scientific community, throughout the period of negotiations, on the potential of the BBNJ treaty to promote the creation of new area-based management tools, including MPAs, and fulfil acknowledged gaps in ocean governance. A systematic literature review was conducted, resulting in 80 publications then analysed in detail. From these, a total of 608 key messages were retrieved and classified into: 1) Strengths (S), Weaknesses (W), Opportunities (O) or Threats (T) for a SWOT analysis and 2) one of six categories that cover crucial aspects for the successful implementation of the ABMTs in areas beyond national jurisdiction. A Sentiment Analysis (SA) to these key messages shows that the instrument has been perceived by the scientific community as an opportunity for conserving and achieving sustainable use of biodiversity. However, the scientific community also feels that agreement needs stronger provisions to ensure effective measures, which is reflected by the small number of identified strengths. An overall decrease in sentiment score over the negotiations period, i.e. a growing pessimism, was also observed, which is supported by an increase of weaknesses and threats identified in the final stages of the negotiations. Our results suggest that despite its potential to promote conservation in areas beyond national jurisdiction, the instrument should include a unified definition of MPA, address fishing activities and clarify conflicting terms in its provisions, such as the term “not undermine”. Further, we show that sentiment analysis is a useful tool to evaluate opinion trends and facilitate the integration of different and subjective perspectives into final provisions of complex social-political-environmental agreements, identifying positive and negative attitudes that can enable better solutions to address existing governance challenges in international waters

Feeding diversity index as complementary information in the assessment of ecological quality status

The feeding diversity of macroinvertebrates from the estuary of Mondego was estimated with Shannon–Wiener complementary evenness following the methodology presented in Gamito and Furtado (2009. Ecological Indicators, 9: 1009-1019). Results were compared with those from BAT (Benthic Assessment Tool; Teixeira et al., 2009. Marine Pollution Bulletin, 58: 1477-1786) applied to the same data set, obtained from sampling carried out in 14 estuarine subtidal stations in Spring of 1990, 1992, 1998, 2000 and 2002. The BAT is a multimetric methodology based on three indices, the Shannon-Wiener and Margalef diversity indices, applied in conjunction with AMBI (Marine Biotic Index). To determinate the feeding diversity, each invertebrate was assigned to a feeding group. Six trophic groups were considered: surface deposit feeders, subsurface deposit feeders, herbivores or grazers, suspension feeders and suspension/deposit feeders. The carnivorous, omnivorous and scavengers were all grouped together, forming the sixth group. The results obtained with both tools pointed out, in general, to the same tendencies. However, in few occasions the feeding diversity pointed out to a high or a bad ecological quality condition whereas the BAT indicated a moderate condition. Occasionally, in stations with average species richness, all individuals were assigned to only one to three 2 feeding groups, and the feeding diversity was low. Even if these taxa were included in the first two or three AMBI sensitive groups, with their presence indicating a possible good ecological condition, they all perform the same ecological function, for example, they are all omnivorous. In these cases the trophic functioning of the system is reduced and the lower trophic levels are missing, such as the suspension-feeders and the decomposers or deposit-feeders. On the contrary, a highly diverse trophic assemblage might be found, but composed of taxa assigned to AMBI ecological groups of species indifferent or tolerant to organic enrichment, and of second-order opportunistic species, indicating a moderate ecological condition, while the feeding diversity will be high. The feeding diversity is, therefore, useful as a complementary information index, measuring other aspects of the community organization, which are not required for ecological quality assessment by the WFD, and so not included in metrics such as BAT

A Novel Approach for Deriving Nutrient Criteria to Support Good Ecological Status: Application to Coastal and Transitional Waters and Indications for Use

A huge variability exists in nutrient concentrations boundaries set for the water (WFD) and the marine strategy framework directives (MSFD), as revealed by a survey to EU member states (MS). Such wide variation poses challenges when checking policy objectives compliance and for setting coherent management goals across European waters. To help MS achieve good ecological status (GES) in surface waters, different statistical approaches have been proposed in a Best Practice Guide (BPG; CIS Nutrients Standards Guidance) for establishing suitable nutrient boundaries. Here we used the intercalibrated results from the WFD for the biological quality element phytoplankton to test the applicability of this BPG for deriving nutrient boundaries in coastal and transitional waters. Overall, the statistical approaches proved adequate for coastal lagoons, but are not always robust to allow deriving nutrient boundaries in other water categories such as estuaries, in transitional waters, or some coastal water types. The datasets available for analysis provided good examples of the most common problems that might be encountered in these water categories. Similar issues have been found in freshwater environments, for which solutions are proposed in the BPG and which are demonstrated here for coastal and transitional waters. The different approaches available and problems identified can be useful for supporting the derivation of nutrient concentrations boundaries both for the Water and the MSFDs implementation

Establishing causal links between aquatic biodiversity and ecosystem functioning: status and research needs

Understanding how changes in biodiversity affects ecosystem functioning is imperative in allowing Ecosystem-Based Management (EBM), especially when addressing global change and environmental degradation. Research into the link between biodiversity and ecosystem functioning (BEF) has indeed increased considerably over the past decades. BEF research has focussed on terrestrial ecosystems and aquatic ecosystems have received considerably less attention. Due to differences in phylogenetic diversity, ecological processes and reported BEF relationships, however, it may at least be questionable whether BEF relationships are exchangeable between these ecosystems (i.e. terrestrial and aquatic). The aim of the present paper was therefore to pinpoint key areas and bottlenecks in establishing BEF relationships for aquatic ecosystems (freshwater, transitional, and marine). To this end, the available literature with special emphasis on the last 10 years was assessed to evaluate: i) reported mechanisms and shapes of aquatic BEF relationships; ii) to what extent BEF relations are interchangeable or ecosystem-specific; and iii) contemporary gaps and needs in aquatic BEF research. Based on our analysis, it may be concluded that despite considerable progress in BEF research over the past decades, several bottlenecks still need to be tackled, namely incorporating the multitude of functions supported by ecosystems, functional distinctiveness of rare species, multitrophic interactions and spatial-temporal scales, before BEF relationships can be used in ecosystem-based management.publishe

Establishing nutrient thresholds in the face of uncertainty and multiple stressors: A comparison of approaches using simulated datasets

Various methods have been proposed to identify threshold concentrations of nutrients that would support good ecological status, but the performance of these methods and the influence of other stressors on the underlying models have not been fully evaluated. We used synthetic datasets to compare the performance of ordinary least squares, logistic and quantile regression, as well as, categorical methods based on the distribution of nutrient concentrations categorised by biological status. The synthetic datasets used differed in their levels of variation between explanatory and response variables, and were centered at different positions along the stressor (nutrient) gradient. In order to evaluate the performance of methods in “multiple stressor” situations, another set of datasets with two stressors was used. Ordinary least squares and logistic regression methods were the most reliable when predicting the threshold concentration when nutrients were the sole stressor; however, both had a tendency to underestimate the threshold when a second stressor was present. In contrast, threshold concentrations produced by categorical methods were strongly influenced by the level of the stressor (nutrient enrichment, in this case) relative to the threshold they were trying to predict (good/moderate in this instance). Although all the methods tested had limitations in the presence of a second stressor, upper quantiles seemed generally appropriate to establish non-precautionary thresholds. For example, upper quantiles may be appropriate when establishing targets for restoration, but not when seeking to minimise deterioration. Selection of an appropriate threshold concentration should also attend to the regulatory regime (i.e. policy requirements and environmental management context) within which it will be used, and the ease of communicating the principles to managers and stakeholders

A spatial explicit vulnerability assessment for a coastal socio-ecological Natura 2000 site

In line with the global trend, the Ria de Aveiro coastal lagoon is subjected to multiple co-occurring pressures threatening vital benefits flowing from nature to people. The main objective of this research was to assess the status of habitats important for ecosystem services in the Ria de Aveiro by identifying vulnerable areas to anthropogenic threats. The pressures from seven relevant human activities (recreation, services, aquaculture, agriculture, commercial development, unintended impacts from management, and invasive alien species) were analysed based on their spatiotemporal distribution (exposure) and impact over the EUNIS habitats (EUNIS codes A2.2, A2.22 – sand flats and beaches; A2.3 – mud flats; A2.61 – seagrasses; A2.5, A2.53C, A2.535, A2.545, A2.554 – salt marshes; and, X10 – ‘Bocage,’ a landscape of small-hedged fields) in seven distinct landscape units. A prospective scenario, co-developed for the year 2030, was evaluated using a map-based risk assessment tool and brought forward the near-term vulnerability of the seagrass biotope. The highest risks posed to intertidal habitats (mud flats and salt marshes) were driven mainly by environmental management activities that support critical socio-economic sectors. Our methodology evaluated plausible threats to habitats in the near term, established baseline knowledge for the adaptive management process in Ria de Aveiro Natura 2000 site, and showcased how future assessments can inform the operationalization of ecosystem-based management as new information becomes available