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Conservation managers need to be able to assess and prioritize issues that may affect their target habitats and species. In the Baie de Somme, France, conservation issues affecting overwintering shorebirds include hunting pressure, cockle fishing, recreational disturbance, Spartina encroachment, and changing sediment levels. We used an individual-based model to predict the effect of these issues on the survival of three shorebird species: dunlin Calidris alpina, oystercatcher Haematopus ostralegus and curlew Numenius arquata. In the model, removing hunting from the mudflats in the eastern part of the estuary had the greatest positive effect on shorebird survival. Oystercatcher survival decreased markedly when stocks of large cockles were reduced to <250 m-2 or numbers of fishermen per day were doubled. Short-term disturbance events, such as walkers, had more effect on shorebird survival than long-term events, such as fishermen. Dunlin, as a protected species, were able to feed outside the Reserve Naturelle and were unaffected by disturbance within the Reserve. Oystercatcher survival decreased when the number of disturbance events within the Reserve exceeded one h-1, and curlew survival when disturbance events exceeded six h-1. Spartina encroachment caused dunlin survival to decline steadily as feeding habitat was lost. Dunlin were also the species most affected by changes in sediment levels, likely to occur through either sedimentation or sea level rise. [ABSTRACT FROM AUTHOR]

Aerobic anoxygenic phototrophic bacteria (AAPB) are a group of heterotrophic bacteria capable of photosynthesis. The dynamics of AAPB in the East China Sea, a typical marginal sea characterized by diverse physical-chemical and ecological conditions, were investigated from April 2002 to September 2003. The results showed that the abundance of AAPB varied from 0.16 to 7.9 × 104 cells mL−1 and the percentage of AAPB (AAPB%) in the total heterotrophic bacterial abundance varied from 0.5% to 11.6% over a gradient of environmental conditions. The abundance of AAPB and AAPB% was higher in coastal and continental shelf waters than in oceanic waters. An interesting seasonal pattern was observed in the Yangtze River estuary: the abundance of AAPB was highest in summer and lowest in winter; however, AAPB% was higher in winter than in the other seasons. Throughout the investigation period, variation of AAPB abundance with temperature was much less than that of nonAAPB abundance, suggesting that low temperature was not a limiting factor for AAPB in this case. Close correlation between AAPB and chlorophyll a was observed in each season, suggesting that dependence of AAPB on dissolved organic carbon produced by phytoplankton (PDOC) may be one key factor controlling AAPB distribution. [ABSTRACT FROM AUTHOR]

More than ever, there is a need to integrate restoration ecology, as practiced by the scientific community, and ecological restoration, a province that is largely, but not entirely the purview of practitioners. Success in some coastal restoration projects is increasingly measured in the context of practitioner skills and cultural goals rather than by the manifestation of underlying ecological principles and mechanisms in the restoration process. Especially in human-dominated landscapes, restoration practices should attempt to balance human needs with those of extant biota in a consensus based combination of restoration ecology and ecological restoration criteria. The goal is to devise plans at the appropriate scale that allow humans and other biota to share space and resources in an increasingly complex landscape. No matter where restoration takes place, both ecological fidelity (in ecocentric terms) and human dimensions (in anthropocentric terms) must comprise the restoration design, but ultimately in proportion to human density in the landscape. Without this integration, compromise, and balance, restoration will not likely prosper in the mainstream of society. [ABSTRACT FROM AUTHOR]

In the framework of rehabilitation efforts to enhance the ecological value of closed-off estuaries, we studied the effects of restoring a tidal movement and seawater incursion on soil nitrogen conversion rates and vegetation response of semi-natural and agricultural grasslands in an outdoor mesocosm experiment. Intact soil monoliths including vegetation were collected in June 2004 on two locations on the shores of the Haringvliet lagoon in the south-western part of the Netherlands, which used to be a well-developed estuary before closure in 1970. For more than 1 year, soil monoliths were continuously subjected to a full-factorial combination of tidal treatment [stagnant/tidal (0.20 m amplitude)] and water type [(freshwater, oligohaline (salinity = 3)]. Soil, soil moisture and water nitrogen concentrations were monitored for a year, as well as vegetation response and nitrogen conversion rates in the soil. As expected, nitrogen mineralization rates were enhanced by the tidal treatment in comparison with the stagnant treatment. Denitrification rates however, were much less affected by tide and were even lower in the tidal treatments after 3 months in the agricultural grassland soils, implying that in general, soils were more oxic in the tidal treatments. Oligohaline treatments had virtually no effect on soil nitrogen conversion rates compared to freshwater treatments. Vegetation performance, however, was lower under saline conditions, especially in the semi-natural grassland. No further significant differences in response to the tidal and oligohaline treatments were found between the two soils although they differed strongly in soil characteristics. We conclude that if the rehabilitation measures in the former Haringvliet estuary are carried out as planned, drastic changes in soil nitrogen processes and vegetation composition will not occur. [ABSTRACT FROM AUTHOR]

The bottom sediments of the turbidity maximum area of the Scheldt estuary were mapped in 1999 using echo sounding, sidescan sonar and grain-size analyses of bottom sediments. Four sediment types, sand, muddy sand, sandy mud and mud were recognised. Mud, with very little sand, occurs mainly in the access channels to the sluices giving access to the harbour docks of Antwerp. The sediments of the main channel have a sandier texture. One might conclude that the total mud stock in the middle estuary has increased, both between 1964–1986 and 1986–1999, but on the contrary the mud supply from the river, the mud stock in the river channel and the mud supply to the lower estuary have all decreased. The increase in the mud stock in the area as a whole was completely at the expense of mud deposition in the access channels to the sluice gates giving access to the harbour of Antwerp. The mud stock in the river channel decreased over the years because of a decreasing mud supply from the river. The mud stock in the river channel shows variations that are directly related to fluctuations in the river load. When the suspended matter decreased during a certain year the supply of silt and clay particles decreased correspondingly and the resuspension-deposition mechanism caused a relative increase of the sand fraction in the bottom sediments in that year. [ABSTRACT FROM AUTHOR]

Many scientists grapple with the increasingly unclear distinctions between science, policy and society. Finally, the organisation focus explores boundary organisations and how valuable these can be to link multiple stakeholders, frame problems, and embed science and policy alternatives in useful and credible ways. [Extracted from the article]

Estuarine habitats of southeast Australia have been undergoing changes characterized by a reduction of saltmarsh and an increase of mangroves. Incorporated into these changes have been mangrove migration into saltmarsh areas, thus contributing to the latter's decline. At the same time, rapid and extensive change in the catchments of many estuaries has occurred as a result of urban and rural development. It has been estimated that the changes observed between mangrove and saltmarsh wetland vegetation is caused by a series of processes, including urbanization and increased population pressure, increased rainfall, increased nutrients, mangroves recolonizing previously cleared areas, engineering works and subsequent altered tidal patterns, sea-level rise, and subsidence of intertidal flats. Planning strategies are suggested that can be implemented in an integrated manner to mitigate the threats from these processes and to ensure the sustainable management of mangrove and saltmarsh wetlands. [ABSTRACT FROM AUTHOR]

Recognition of the benefits to society supported by estuary ecosystem functions and services, and threats to these benefits posed by human activities, has led to various public programs to restore and protect estuaries at the federal, state, and local levels. As available budgets shrink, program administrators and public elected officials struggle to allocate limited restoration and protection funds to the highest priority areas. Economic benefit and cost information can provide useful inputs into this decision-making process by quantifying estuary restoration and protection benefits and costs in commensurate terms. In this paper, a combined actual and intended travel behavior model is described that can be applied to estimate the recreational fishing benefits of estuary restoration and protection. The model was estimated for recreational fishing in the Lower Atchafalaya River Basin estuary along the Gulf of Mexico, Louisiana, USA coast. Changes in freshwater flows into this estuary may affect redfish and speckled trout game fish populations. The model indicates that changes in catch rates of these two species would have a relatively minor affect on annual fishing trips per angler. However, because total effects may be large when effects per angler are aggregated across total anglers, resource management agencies should consider these changes in recreation benefits when evaluating projects that influence the ecology of coastal estuaries, fish populations, and catch rates. Moreover, in other coastal areas or situations, the responsiveness of angling trips to changes in catch rates may vary because of differences in user populations, environmental conditions, fish populations, and fishing experiences. [ABSTRACT FROM AUTHOR]

The need for a better management of estuaries requires an environmental characterization following a methodology that allows the comparison of distinct estuarine systems and the assessment of their evolution. The peculiar characteristics of estuaries, in particular their intrinsic variability, make this characterization difficult and there is no commonly accepted general methodology available. The approach followed in freshwater ecosystems is generally based on the concept of environmental indicators, but such a concept has not been developed for estuaries. Indeed, a different approach is needed here, due to the spatial heterogeneity and the different time scales associated with the processes that control water quality. This paper presents a proposal for a methodology that starts with observed values and uses a procedure to integrate these values in time and space in order to calculate significant values, upon which normalized indicators are built which take into account criteria based either on legal, scientific or heuristic concentration limits. A normalization is carried out in two steps: (1)application of a mathematical operator to the significant values ,(2) transformation using the concept of penalty curves. This methodology may be complemented with the definition of quality classes, particularly appealing and useful, as tools to communicate with decision makers and the public in general. Water quality data pertaining to the Tejo estuary are used to test the methodology. [ABSTRACT FROM AUTHOR]

Strategic management and planning within estuaries seeks to identify a framework that enshrines sustainability. Any management initiative must address the issues of long- term change; physical, chemical and biological interactions; and system response (including socio-economic interactions). Achieving such a programme will need to take advantage of studies and research at a number of different spatial and temporal scales. These range from global climate change initiatives, through catchment and estuary wide studies to work on specific features (banks, mud flats, etc.). They necessarily consider changes over time scales of seconds to aeons. For strategic planning and management,the goal is to be able to predict change, with a reasonable degree of confidence over a 20 to 50 year time horizon. Given the highly non-linear and complex adaptive nature of estuary systems, absolute predictions may not be possible. Rather, it will be necessary to identify probable/possible outcomes, or system states, as a basis for guiding management actions. This, in itself, will require managers and planners to move away from a prescriptive interventionist approach towards a more adaptive one. [ABSTRACT FROM AUTHOR]

The Humber Estuary Shoreline Management Plan provides the framework for investment in defences to reduce the risk of flooding to people, property and the environment. A key issue is the rise in sea level, which is reducing the standard of protection provided and is increasing erosion. The plan is developed from detailed geomorphological and ecological studies, and extensive consultation with interested organisations and the community. It takes into account the urban and industrial development on the floodplain, high-grade agricultural land, the historic environment and the Humber''s status as an outstanding site for wildlife, which is protected under the Habitats Directive. A key aim is wherever possible to work with natural processes. Another is to ensure that there is no net loss of protected inter-tidal habitat. The options investigated include changes to the existing alignment of the embankments. The overall strategy provides for a continuing line of defence around the estuary and tidal rivers but with the use of managed retreat in some places. The creation of new inter-tidal habitat by this means is to gain more stable and cost-effective defences, and to offset the loss of protected sites, including by coastal squeeze. Further studies are in progress to appraise potential managed retreat sites. [Copyright &y& Elsevier]

Diel variation in the ichthyofaunas associated with Zostera capricorni Ascherson was investigated in three intermittently open estuaries in the Illawarra region, New South Wales. Each estuary showed differing diel shifts in fish assemblages, which appeared to be related to estuary size. In the largest estuary (Lake Illawarra) significantly more species were caught during the night than the day for all months. In contrast, there was little diel variation in the fish assemblages at Werri Lagoon and Shellharbour Lagoon, although many species were only caught during the night at both estuaries. The distinct diel changes at Lake Illawarra was thought to be attributable to the relatively deep channels adjacent to the seagrass beds which are better habitats for larger fishes compared with the shallow sand bars without deep channels throughout the two smaller estuaries. The composition of fish species within the three estuaries were significantly different, although each assemblage was characterised by large numbers of small-sized fish (<100 mm FL) indicating the importance of intermittently open estuaries as fish habitats. It was concluded that night sampling provided a more complete picture of the ichthyofaunas associated with Z. capricorni. As a result, inclusion of night sampling in fish diversity assessments would increase the chance of catching diurnally rare species and therefore attain a better representation of the true community structure. [ABSTRACT FROM AUTHOR]

The U.S. Environmental Protection Agency has released a report entitled Condition of the Mid-Atlantic Estuaries. That report summarizes the findings of several studies conducted by federal and state agencies and academic institutions in Chesapeake Bay, Delaware Estuary, and the coastal bays of Delaware, Maryland, and Virginia, and simultaneously addresses two distinct audiences: environmental managers and the general public. This paper documents the process of preparing the Estuaries Report, emphasizing the lessons learned in merging information from a wide-variety of sources and in reporting the results to multiple audiences. The major difficulties in preparing the report included: 1) choosing a format and topics that adequately addressed both environmental managers and the public, 2) resolving spatial and temporal disparities in the assembled data sets, and 3) establishing threshold values that distinguished between acceptable and unacceptable conditions in indicators. Our solutions to these challenges and alternatives are discussed. We conclude that a small team of knowledgeable scientists can effectively merge the information of diverse sources into a document that is useful to both environmental managers and the interested public. However, considerable interaction between the team and other scientists was necessary to resolve ambiguities and assure relevancy and accuracy. These findings support the proposition that the vast sources of existing environmental information can be easily and effectively used to assess the ecological condition across large regions. [ABSTRACT FROM AUTHOR]

In order to examine the condition of biota in Atlantic coast estuaries, "Contaminant Exposure and Effects—Terrestrial Vertebrates" database (CEE-TV) has been compiled through computerized search of published literature, review of existing databases, and solicitation of unpublished reports from conservation agencies, private groups, and universities. Summary information has been entered into the database, including species, collection date (1965–present), site coordinates, estuary name, hydrologic unit code, sample matrix, contaminant concentrations, biomarker and bioindicator responses, and reference source, utilizing a 98-field character and numeric format. Currently, the CEE-TV database contains 3699 geo-referenced records representing 190 vertebrate species and >140,000 individuals residing in estuaries from Maine through Florida. This relational database can be directly queried or imported into a Geographic Information System to examine spatial patterns, identify data gaps and areas of concern, generate hypotheses, and focus ecotoxicological field assessments. Information on birds made up the vast majority (83%) of the database, with only a modicum of data on amphibians (<0.1%). Of the >75,000 chemical compounds in commerce, only 118 commonly measured environmental contaminants were quantified in tissues of terrestrial vertebrates. There were no CEE-TV data records in 15 of the 67 estuaries located along the Atlantic coast and Florida Gulf coast. The CEE-TV database has a number of potential applications including focusing biomonitoring efforts to generate critically needed ecotoxicological data in the numerous "gaps" along the coast, reducing uncertainty about contaminant risk, identifying areas for mitigation, restoration or special management, and ranking ecological conditions of estuaries. [ABSTRACT FROM AUTHOR]

Microtidal estuaries are common on the world's coastline and a variety of forms have been described from different environmental settings. Studies around the South African coast indicate the presence of two main categories of microtidal estuary (river- and tide-dominated) with near-permanent surface water connections with the sea. Inlets of tide-dominated microtidal estuaries are maintained by tidal currents and contain a distinctive tripartite facies variation along the estuary axis. Inlets of river-dominated estuaries are maintained by river discharge and contain river-dominated back-barrier sediments adjacent to the estuarine barrier. The development of each of the types of system depends on fluvial sediment supply, fluvial discharge, coastal gradient and nearshore sediment dynamics. While a broad spatial pattern exists in the development of these types of estuary, evolutionary pathways are described that link the two types of system (and other estuary forms) in a space-time continuum. The management implications of these findings are discussed. [ABSTRACT FROM AUTHOR]

The Changjiang Delta (CD) is one of well-studied large deltas of critical socio-economical and ecological importance regionally and global representativeness. Cumulated field data and numerical modeling has facilitated scientific understanding of its hydro-morphodynamics at multiple spatial and time scales, but the changing boundary forcing conditions and increasing anthropogenic influences pose management challenges requiring integrated knowledge. Here we provide a comprehensive synthesis of the multi-scale deltaic hydro-morphodynamics, discuss their relevance and management perspectives in a global context, and identify knowledge gaps for future study. The CD is classified as a river-tide mixed-energy, muddy and highly turbid, fluvio-deltaic composite system involving large-scale land-ocean interacted processes. Its hydro-morphodynamic evolution exhibits profound temporal variations at the fortnightly, seasonal, and inter-annual time scales, and strong spatial variability between tidal river and tidal estuary, and between different distributary channels. As the river-borne sediment has declined >70%, the deltaic morphodynamic adaptation lags behind sediment decline because sediment redistribution within the delta emerges to play a role in sustaining tidal flat accretion. However, the deltaic channels have become narrower, deepened and growingly constrained under cumulated human activities, e.g., extensive embankment and construction of jetties and groins, possibly initiating a decrease in morphodynamic activities and sediment trapping efficiency. Overall, the CD undergoes transitions from net sedimentation and naturally slow morphodynamic adaptation to erosion and human-driven radical adjustment. A shift in management priority from delta development to ecosystem conservation provides an opportunity for restoring the resilience to flooding and erosion hazards. The lessons and identified knowledge gaps inform study and management of worldwide estuaries and deltas undergoing intensified human interferences. • A comprehensive synthesis of multi-scale hydro-morphodynamics and management challenges in the Changjiang Delta (CD) • A conceptual model of the hydro-morphodynamics for river-tide mixed-energy delta • Knowledge gaps in hydro-morphodynamic studies identified for CD and similar systems [ABSTRACT FROM AUTHOR]

Sediment samples were collected to clarify the effect of changing sedimentary environment under long-term reclamation on heavy metals (Cr, Zn, Pb, Cu, Cd, and Ni) in a partially mixed estuary (Modaomen) of the Pearl River Delta. The ecological toxicity and source apportionment of these metals were discussed as well. The metal species during the 2010s (as 2015, 2018) was more enriched than that during the 2000s (as 2003) and 1990s (as 1991). This estuary overall suffered from a "moderate-to-high" pollution status. The element Cd was a major concern for the ecosystem's health because of its high toxicity. Sediment quality guidelines suggested that adverse biological effects were likely to be caused by Cu and Cd in the early adjustment stage, while the threats to marine organisms caused by the elements of Cu, Cr, Zn, and Ni were elevated during the 2010s. Two receptor models of PCA-MLR and PMF quantified the source types and contributions of these heavy metals. Strong intensity of industrial activities coupling with agricultural applications and import of adjacent seas were responsible for the enriched accumulation of heavy metals in sediments. Metal source apportionment would help to control the metal input into the estuary; identifying the role of sedimentary environment on heavy metals can inform the sediment quality management in the estuary. • This estuary overall suffered from a "moderate-to-high" pollution level. • The acting mechanism of metal species under the long-term reclamation was evaluated. • Ecological toxicity caused by Cd and Cu posed a threat to the marine organisms. • PCA-MLR and PMF quantified the source types and contributions of heavy metals. [ABSTRACT FROM AUTHOR]

Understanding the metal pollution can help governments and estuary management groups manage metal inputs. Here, we comprehensively analyzed the behaviors of seven metals Cd, Zn, Cu, As, Pb, Cr, and Hg in water and the responses of these metals to hydrological connectivity in the Pearl River Estuary. The analyses were based on the field measurements of August-2016 in the estuary and January-2016 in the upper river mouth. We also assessed the ecosystem health of these metals. Overall, this estuary had an overall moderate pollution level, with occasional severe perturbations. The mean concentration of individual metal was in the order of Zn > As > Cu > Cr > Pb > Cd > Hg. The eastern estuary was more heavily polluted by metals (notably, Zn, Cd, and Cu) than the western estuary; this condition was attributable to sewage and industrial effluent discharges from the eastern urban cities of Dongguan and Shenzhen. Longitudinally, high levels of Cd and Zn appeared in the upper estuary, while elevated levels of Cu, As, Pb, Cr, and Hg were found in the middle and lower estuaries. The riverine inputs and estuarine mixing significantly influenced the distribution and movement of trace metals in the estuary, and have contributed to phytoplankton productivity (chlorophyll- a > 10 μg/L). River inflow inhibited the vertical diffusion of metals, and tidal currents facilitated surface-to-bottom mixing. Cu and Cd posed ecological risks. We determined the source contributions and transport routes of the metals using principal component analysis combining with multiple linear regression. The results of this study suggest that the source apportionment of metals can help to manage the source input entering into the estuary. Further, identified hydrological connectivity of metals can inform water quality managers in the highly anthropogenically influenced estuary. [Display omitted] • The metal concentration was in the order of Zn > As > Cu > Cr > Pb > Cd > Hg. • Ecological risks caused by Cu and Cd were high to the ecosystem's health. • We discussed the effect of hydrological connectivity on metals. • River-tide dynamics influenced surface-to-bottom mixing of the metals. • PCA-MLR was useful to identify the source types and contributions of metals. [ABSTRACT FROM AUTHOR]

An understanding of suspended particulate matter (SPM) dynamics is of great importance to design awareness and management strategies of estuaries. Using a Laser In Situ Scattering and Transmissiometry (LISST) instrument, variations in suspended particle size volumetric concentrations (VC) and particle size distributions (PSD) were measured at six sites within Port Curtis estuary (Australia). The port is a macrotidal estuary with significant economic and environmental importance. Observed VC and SPM sizes demonstrated spatial and temporal trends strongly controlled by the variable energy conditions operating on the neap and spring cycle timescale, with a clear trend towards increasing concentrations and decreasing SPM sizes with increasing tidal ranges. Mid-estuary sites were characterized by the greatest depth-averaged VC under transitional and spring conditions. Estuary-wide mean spring tide total water profile concentrations revealed a near 300% increase in comparison to neap tide condition concentrations. In the upper-estuary sites the mean contribution of the combined 2.5–35 µm size classes to the total profile PSDs was greatest during all tidal conditions, whilst within the lower-estuary site the combined 35–130 µm size classes were greatest. Mean contributions of the largest size class (300–500 µm) dominated surface-waters throughout the estuary during the neap tide period, which when compared with the transitional and spring tide conditions, demonstrated changes of −82% to −48% and −82% to −40%, respectively. Overall, the results from this case study provides further evidence of the important influence of neap and spring tidal regimes on SPM dynamics within estuarine settings and the need to observe parameter dynamics on such timescales. [ABSTRACT FROM AUTHOR]

[Display omitted] • The concentrations of various N forms in dry season was higher than that in wet season. • Gate construction significantly changed the N transport processes. • Sewage/manure has become the major N source in waterbody. • Urban N sources input has surpassed that of agricultural sources. • Sediment N release became the second-largest N source in waterbody under the hydrodynamic disturbances. Revealing nitrogen source and transport mechanisms are essential to achieving optimal nitrogen management in urban estuaries and gate-controlled rivers. However, in plains river networks, gate and/or dam construction make the nitrogen sources difficult to trace. In this study, seasonal water samples from typical urban estuaries and gate-controlled rivers in northern Taihu Lake were analyzed using statistical analysis and stable isotope analysis in R (SIAR). The results show that the concentrations of various nitrogen forms showed obvious spatial–temporal distribution characteristics by multiple sources. Specifically, the nitrogen concentration was lower during the wet season than the dry season (T = 6.02, p < 0.01). Gate construction had a dual effect on the water environment, because it changed both the nitrogen transport processes and the nitrogen enrichment risk between the river side and lake side. The δ18O-NO 3 - and δ15N-NO 3 - values were sensitive to anthropogenic activity intensity and urbanization process, showing the following order of δ15N-NO 3 - values: Countryside > Suburbs > Downtown, and Construction Land > Forest-grassland > Farmland. While, a contrary trend was observed among the variations in δ18O-NO 3 - values. According to the SIAR model, sewage/manure, fertilizer, and sediment nitrogen (sediment N) were the main nitrate sources, accounting for 42.68%, 23.79%, and 23.71%, respectively. The proportion of urban nitrogen discharge has surpassed that of agricultural sources, becoming the largest nitrogen source in the waterbody. Under the coupling of meteorological conditions and estuary shape, the endogenous nitrogen released from sediment became the second largest contributor in some estuaries. These findings suggest that it is necessary to strengthen the control of urban exogenous nitrogen input and sediment nitrogen endogenous release to enable future estuarine nitrogen management and habitat restoration. [ABSTRACT FROM AUTHOR]

• Established an evaluation index of tidal flat ecological stability (ECO-CSI). • Urbanization and the traffic road were the key negative artificial factors. • The sediment discharge, the precipitation, etc. were the key guarantee factors. • The threshold value of the Liaohe River sediment discharge was 792.91×104t y−1. • The threshold value of the scale of traffic roads was 770.9244 hm2. The tidal flat, located at the forefront of the coastal estuary wetland, serves as a peripheral defense line to maintain the stable ecological function of the estuary wetland. Therefore, the accurate identification of the stable state of a tidal flat is rendered as the decision-making basis for the restoration and management of estuary wetland ecosystems. Conducted at the tidal flat of the Liaohe Estuary Wetland, the study established a comprehensive evaluation index of tidal flat ecological stability (ECO-CSI) based on the Pressure-State-Response model and Rough Set theory. The driving factors and threshold values which affected the stability of the tidal flat were identified. The results showed that the average ECO-CSI value of the tidal flat during the past 30 years was 0.44 indicating, in general, a relatively stable state of the tidal flat. On the other hand, in 2017 the ECO-CSI value was 0.25, pointing that the tidal flat is in an unstable state currently. Among the factors affecting the tidal flat ecological stability, the artificial development activities were the major driving factors, and the urbanization and the traffic road scale were the key driving factors leading to the instability of the tidal flat. Of the natural factors, the sediment discharge, the flow in flood season, and the precipitation in the upstreams were the key guarantee factors for maintaining the material supply of the tidal flat. The threshold values for maintaining the ecological stability of the tidal flat in the Liaohe Estuary wetland were determined that the sediment discharge of the Liaohe River should be not less than 792.91 × 104t⋅y-1 and the scale of traffic roads in the tidal flat should be less than or equal to 770.9244 hm2. Hence, in the development and utilization of tidal flats and coastal wetlands, unreasonable human development activities should be minimized to avoid damage to the integrity and natural dispositions of the tidal flat. In this way, the stability of the tidal flat could be improved, contributing to the ecological security for the overall stability of the estuary wetland ecosystem. [ABSTRACT FROM AUTHOR]

Collaborative nonregulatory programs can benefit the long-term sustainability of environmental resources. Such programs benefit from extensive planning and assessment relative to ecological systems as well as public participation. While many programs use adaptive management as a guiding programmatic framework, few programs successfully integrate social and human context into their adaptive management frameworks. While this adaptive governance framework can be successful, many potential challenges arise when incorporating public stakeholders into the adaptive management framework. To reduce those challenges, programs need participation from diverse stakeholder groups that represent multiple communities of interest, place, and identity. The participatory process benefits from a diverse group of stakeholders and can result in successful management of environmental resources. We highlight the participatory co-management process of three newly developing nonregulatory programs that are modeled after the United States EPA's National Estuary Program in the Perdido and Pensacola Bay systems, Choctawhatchee Bay, and the St. Andrew and St. Joseph Bay systems (Florida USA). This case study illustrates how collaborative nonregulatory programs can be implemented not only in the United States, but also in other regions of the world. • Collaborative stakeholder-driven groups are important in achieving objectives for environmental resource management. • Adaptive Management is useful for evaluating effects of project implementation and for participation among stakeholders. • The programs are also benefiting from existing partnerships that have implemented conservation-related projects in the past. [ABSTRACT FROM AUTHOR]

• Integrate science and management is a challenge to improve conservation strategies. • Macrofaunal patterns were assessed and further discussed with local stakeholders. • High mud content in the sediment were correlated with reduced macrofaunal richness. • Taxa richness can be an indicator related to initial ecosystem changes. • These indicators are useful to implementing an adaptive ecosystem-based management. The integration of biodiversity knowledge with management needs in coastal protected ecosystems is a current challenge that requires a social-ecological perspective, especially in view of the current scenario regarding climate changes. At the southeastern Brazil, estuaries inside protected areas highlight as a great source of ecosystem services connected to the biodiversity, such as the food provisioning for local communities (i.e. fishery supply). However, climate change models considering the last four decades alert to an annual rainfall increase in the region, threatening the estuarine biodiversity and its associated ecosystem services. Here, we evaluated how estuarine macrofaunal distribution could be used as ecological indicators to support the stakeholders management needs in subtropical Marine Protected Areas (MPAs). The intertidal macrofauna distribution was assessed along physical gradients in estuaries within MPAs of the southeastern Brazil, testing the effects of salinity and sediment properties on taxa richness. Then, implications of these ecological findings were discussed with the local users and managers of the MPAs, aiming to stipulate indicators and management proposals considering the rainfall increase predicted for the region. We found that macrofauna community varied between estuarine zones along the physical gradients. High values of mud and organic content in the sediment were correlated with reduced taxa richness in the upper estuarine zone, indicating high vulnerability of biodiversity to a possible estuarine mud input connected to the expected rainfall increase. Stakeholders noted that this knowledge could assist with spatial planning for an adaptive management of the biodiversity use rules on the MPAs, with focus on the ecosystem services conservation (ecosystem-based management). Stakeholders suggested using biodiversity hotspots to guide estuarine areas classification (no-take zones and sustainable use zones), maintaining the resources use rules adaptable according to the biodiversity changes. In this regard, our data revealed important bioindicators, such as the macrofaunal richness, which can be monitored as "early signals" to assess eventual ecosystem alterations related to the climate changes. These signals can include loss in taxa richness, extirpation of species exclusively found on the lower estuarine zone (sensitives to mud input) and changes in the distribution or abundance of dominant taxa. We suggest that understanding the relationships between macrofaunal indicators and ecosystems services, associated with continuous monitoring, are the key steps to implementing an adaptive ecosystem-based management of these protected estuaries in the current changing scenario, contributing to decision making at local scale that respond to global challenges, as the UN Ocean Decade. [ABSTRACT FROM AUTHOR]

• A quantitative method for evaluating response of estuarine ecosystem to hydrological variations was established. • The unity of hydrological and ecological data on time scale was realized. • Daily water and sediment fluxes into estuary explained 56% of change in fish. • Both low and high water and sediment fluxes limited the estuarine ecosystem. • Advancing the discharge time of dam to spring can benefit ecology. The water and sediment fluxes into the estuary from upstream highly influence the estuarine ecosystem. The lack of method to evaluate the impact of daily water and sediment fluxes on ecosystem has limited the ecological management of estuary. Therefore, it is important to find a quantitative method for analysing the response of estuarine ecosystem to daily water and sediment fluxes into the estuary. Based on long time sequenced data, we aim to determine the dynamic response of fish communities to the interannual and seasonal variations of water and sediment fluxes, providing a novel method for the regulation of water and sediment process in dammed rivers. We establish a functional regression model and improve Functional Linear Regression That is Interpretable (FLiRTI) method to quantify the dynamic response relationship between the annual catch per unit effort (CPUE) and the daily water and sediment fluxes into the Yellow River Estuary from 1980 to 2011. The results showed that the water and sediment fluxes into the estuary explained 56% of the variability in the CPUE. Low fluxes during the spawning period (April-May) and high fluxes during the dam discharge period (June-July) were not conducive to estuarine fisheries. By increasing freshwater inflow in spring to 3.1 or 4.3 billion m3, the cumulative effect on estuarine fish communities can be increased by 20% and 44%, respectively. We propose a functional regression method to quantify the response of estuarine fish communities to water and sediment fluxes into the estuary. We suggest that advancing the discharge time of dam to spring, a suitable spawning environment for fish can be provided, thus effectively increasing fish production in the estuary. This study overcomes the limitation of number of species as well as the disunity of hydrological and ecological data on time scale, providing new idea for estuarine ecology research. [ABSTRACT FROM AUTHOR]

Presents a study which illustrated some of the issues in program evaluation, measuring policy success and implementing integrated conservation plan of the Fraser River Estuary Management Program in Canada. Emergence of integrated planning; Water quality trends; Habitat conservation; Survey method; Results and discussion.

Intertidal seagrasses often occupy areas of high ecological importance that are also targeted for human activities, such as shellfishing and leisure walking. These activities could affect the growth or survival of seagrass. The society at large lacks knowledge of the ecological relevance of seagrasses and their vulnerability, presenting an obstacle for their conservation. Here, the Oka estuary (Basque Country, N. Spain) is used as a case study to analyse the spatial extent of shellfishing activities in seagrass (Zostera noltei). This estuary holds 84% of the intertidal seagrass meadows present in the Basque Country and is visited during the year by professional and recreational shellfishers. Bait digging is legal year-round, and clam digging (by professionals only) from October to February. Human presence over 11 years averaged 17 people on the tidal flat in each daylight hours from August to October. Each professional shellfishing daily trip affected 7.4–21.6 m2 by fishing and 110–188 m2 by trampling in seagrass, but was substantially different between clam and bait (crustacean, worm) fishing. Scaling up this area to estimated annual number of shellfishers, 8–69% of the total seagrass area is trampled and 1–9% is dug per year. In comparison to a habitat suitability map for seagrass, 98% of trampling occurred within a very highly suitable area for seagrass presence (i.e., >90%). This pressure could adversely affect seagrass density and prevent the expansion of meadows into areas suitable for seagrass. Management of public impacts to seagrass in this estuary could occur through prohibition of some activities in seagrass and awareness campaigns among shellfishers and walkers. [Display omitted] • Seagrass surface is declining in the Basque estuaries. • Trampling and digging by shellfishers are the main perturbing human factors for Basque seagrasses. • Shellfishers trampling and digging on seagrasses is quantified for the Oka estuary. • Awareness-raising campaign and some banning measures are proposed to protect and conserve seagrasses in the Oka estuary. [ABSTRACT FROM AUTHOR]

When studying sustainable ecotourism, the ecotourism system can be better understood as a complex association of various elements that affects the local society and wildlife habitats. The purpose of this study is to plan an ecotourism system for the wise ecotourism resource management of estuary wetlands by using a resilience principle-based systems thinking approach. This study suggests an integrated management plan that considers diversity, connectivity, learning, participation, and polycentric governance to solve universal and important issues, such as estuary dam removal, urbanization, and natural resource use in the estuary's social-ecological system. The ecotourism system plans suggested in this study include minimizing ecological conflict and load through an improved sense of responsibility among stakeholders and strengthened protective activities. The results of this study suggest appropriate roles for various stakeholders in the management of tourism resources that can be used to establish new guidelines for ecotourism destination planning. [ABSTRACT FROM AUTHOR]

Anadromous sub-populations of stenohaline freshwater fish are vastly understudied in the estuarine environment. The purpose of the present study was therefore to study the population ecology, growth rate, and physico-chemical environment of an anadromous sub-population of European perch (Perca fluviatilis) from the western Baltic Sea. Fish (301) were marked with external identification tags, and anglers and fishermen reported recaptures in a citizen science set-up over three years. In addition, scale samples were collected for population growth rate determination. Furthermore, water temperature, salinity, and oxygen concentration were monitored in the area. The fish showed a consistent annual migration pattern over the three years residing in a bay during summer while being in a delta during autumn, winter, and spring. The population had a high growth rate, but a meta-analysis showed that growth of European perch is not distinctly different between estuarine and freshwater populations. The average salinity measured in the area was around 10, but increased on multiple occasions to salinity levels known for being physiologically challenging for European perch. We argue that high growth rates of estuarine European perch is more likely due to high food availability and low interspecific competition in this environment, rather than due to physiologically optimal salinities. Furthermore, the European perch in the present study lived on the edge of the species salinity tolerance, and the migration into the delta during winter is likely a combination of avoiding high salinities at low temperatures and a spawning migration. These results are important knowledge for the management of estuaries and coastal areas, especially as climate change is locally altering these environments drastically, and calls for further studies on other anadromous sub-populations of stenohaline freshwater fish. • The fish resided in a bay during summer and overwintered in a delta. • Growth rate of European perch is not different in estuaries and freshwater habitats. • Anadromous European perch temporarily experience and survive salinities up to 22. • High salinity incidents co-occurred with hypoxic conditions. [ABSTRACT FROM AUTHOR]

Understanding the transportation of polycyclic aromatic hydrocarbons (PAHs) across the water-sediment interface can help researchers to partition their sources while being particularly important for managing PAH input. This study fully explored the PAH dynamics between water and sediment in a tide-dominated estuary. The monthly concentration of ΣPAHs in sediments ranged from 325.47 to 1098.49 ng/g (dry weight), while that in water varied from 154.00 to 725.80 ng/L. The PAH levels found in the present study were relatively high in comparison with other estuarine systems worldwide. The high-molecular-weight PAHs were more readily redissolved from sediment to water, while the low-molecular-weight PAHs were mostly in an unsaturated state with diffusion occurring from water to sediment. The seasonal differences of ΣPAHs were significant and were largely controlled by the changes in sediment properties, marine currents, and water temperature. The diagnostic ratios revealed that predominant sources of PAHs were pyrogenic processes and petrogenic inputs. • Understanding PAH dynamics between water and sediment is particularly important. • The Humen estuary was polluted at a moderate-to-high level. • TOC significantly influenced the behaviors of PAHs. • PAH sources were apportioned via diagnostic ratios. [ABSTRACT FROM AUTHOR]

Estuarine ecosystems are important in terms of biodiversity processes because there are intense interactions between the river and sea environments. Phytoplankton and zooplankton have been shown to be ecological indicators of the water quality status in estuary ecosystems. Therefore, a comprehensive evaluation of the effects that multiple pressures have on the phytoplankton and zooplankton communities in estuarine ecosystems is essential. In this study, water samples from 29 stations were collected from the Liaohe Estuary over three different seasons, and biotic factors (i.e., phytoplankton and zooplankton) were obtained and compared. The results showed that there were significant temporal and spatial variations in the phytoplankton and zooplankton communities from the Liaohe Estuary. The correlation analyses showed that water temperature was the most important factor regulating the variation in phytoplankton communities, whereas the main driving force for the zooplankton was nutrient concentrations. Large amounts of nutrients entered the estuary in spring and summer due to intensive human activities in the Liaohe River basin. The inflows by the Liaohe River introduced some phytoplankton and zooplankton into the estuary, such as Coscinodicus asteromphalus , Chaetoceros decipiens , and Schmacheria poplesia. The impacts of Liaohe inflows on the estuary region gradually decreased as the distance from the inlet increased and this change was mediated by marine diffusion. The results from this study will improve knowledge about planktonic communities in estuarine ecosystems and provide a theoretical foundation for estuary environmental management. Image 1 • Seasonal patterns of phytoplankton and zooplankton were observed in Liaohe estuary. • Water temperature was the main factor affecting the phytoplankton communities. • The zooplankton in Liaohe estuary was largely regulated by the nutrient contents. • The impacts of river inflows on Liaohe estuary were intensive in spring and summer. • The impacts of river inflows were gradually decreased as the distance from the inlet. [ABSTRACT FROM AUTHOR]

Human well-being is often an overarching goal in environmental decision-making, yet assessments are often limited to economic, health, or ecological endpoints that are more tangible to measure. Composite indices provide a comprehensive approach to measuring well-being in terms of multi-dimensional components, such as living standards, health, education, safety, and culture. For example, the Human Well-Being Index (HWBI) framework, initially developed for the U.S. fifty states, was recently applied to quantify human well-being for Puerto Rico. However, the paucity of data at spatial scales finer than state or county levels, particularly for social metrics, poses a major limitation to quantifying well-being at neighborhood-scales relevant to decision-making. Here we demonstrate a spatial interpolation method to fill in missing fine-scale data where coarser-scale data is available. Downscaling from municipio (i.e., county-equivalent) to census-tract revealed a greater range of variability in well-being scores across Puerto Rico, in particular, a larger proportion of low well-being scores. Furthermore, while some components of wellbeing (e.g., Education, Health, Leisure Time, Safety and Security, Social Cohesion) showed consistent improvement over time from 2000 to 2017 across Puerto Rico, others (e.g., Connection to Nature, Cultural Fulfillment, Living Standards) were variable among census tracts, increasing for some but declining for others. We use a case study in the San Juan Bay estuary watershed to illustrate how approaches to quantify baseline levels of well-being can be used to explore potential impacts of management actions on communities, including to identify environmental justice inequalities among neighborhoods. Spatial clustering analysis was used to identify statistically significant cold or hot spots in well-being. This study demonstrates how indicators of well-being, coupled with interpolation methods to overcome limitations of data availability, can help to monitor long-term changes over time and to better communicate the potential value of ecosystem restoration or resource management. [ Image 1 ] • Neighborhood-scale human well-being index was calculated for Puerto Rico. • Spatial interpolation was used to overcome limitations in data availability. • Health, education, social cohesion generally increased across Puerto Rico from 2000 to 2017. • Living standards, connection to nature, cultural fulfillment declined in many areas. • Neighborhoods in the San Juan Bay watershed were highly variable in well-being. [ABSTRACT FROM AUTHOR]

The Logan-Albert estuary in southeast Queensland, Australia, has high biodiversity and supports multiple economic and recreational services. Elevated nutrient and sediment loads have been a longstanding management issue for the estuary. We investigated the spatial and seasonal patterns of nutrients and turbidity along the Logan-Albert estuary and assessed the effects of a recently constructed upstream dam. Nutrient concentrations and turbidity levels were analysed using 15 years of monitoring data from 19 water quality sites throughout the estuary. We hypothesised that the construction of Wyaralong Dam would act as a nutrient and sediment sink which may have positive effects on downstream water quality. Long-term trends of water quality constituents were evaluated using a non-parametric seasonal Mann-Kendall test and the effect of upstream impoundment was assessed with a Before-After Control-Impact (BACI) test. Nutrient concentrations and turbidity levels declined significantly with time in the upper Logan estuary and, to a lesser extent, in the lower Albert estuary. The general improvement of water quality in the upper Logan estuary was attributed to construction of the Wyaralong Dam. Significant decreases in concentrations of total phosphorus (TP) and oxidised nitrogen (NO x -N) along the lower Albert were principally attributed to wetter conditions over the 15-year dataset, which diluted point-source loads from a nearby wastewater treatment plant (WWTP). Our results show that estuarine water quality changes can be highly dynamic with interactions amongst climate and management practices that necessitate long-term monitoring programs with good spatial coverage. • Water quality trends and impact of a constructed dam were assessed • Dam impoundment found to reduce nutrients and turbidity in a subtropical estuary • Dry periods led to a build-up of nutrients and turbidity around treatment plants • Wetter conditions help dilute point loads from wastewater treatment plants • Climatic and management factors often act synergistically [ABSTRACT FROM AUTHOR]

River defragmentation works and an effective fishway with a monitoring station have created conditions for adaptive fishery management in the estuary of Mondego River in central Portugal. Since 2013 fishers, scientists and authorities annually meet to update data for anadromous fish and rules for the upcoming fishing season. Meetings provide an opportunity for approximately 100 licenced fishers to participate, but communication is often hindered by contradictory fisher views and uneven representation between fishers organized in associations (mainly in the lower estuary) and non-members (mainly in the upper estuary). This study presents a survey, voluntarily undertaken by fishers (n = 35) in the upper and lower estuary, aiming to facilitate communication and discursive rationalization of decisions during the annual meetings. The questionnaire includes perceptions of change in environmental and socio-economic conditions, opinions on rules and utility of the meetings and allows comparisons between the upper and lower estuary communities. Results were presented in the 2019 meeting, demonstrating that fishers agree with most rules but also have proposals for rule change and strengthening of participation. The decisions for the 2020 season suggest that the survey permitted a more focused discussion of alternatives and led to modification of rules by consensus that was previously unattained. The survey further showed that a wider governance structure will be required to resolve the emerging problem of an invasive water plant that reduces fishing opportunities and deteriorates river productivity. • Estuarine fishing for anadromous with limited participation in associations. • River defragmentation offers opportunity for participated adaptive management. • Questionnaire survey reports fisher opinion on rules and utility of meetings. • Survey results contribute to deliberation and improved decision-making. [ABSTRACT FROM AUTHOR]

Estuaries are transitional water systems where the hydrodynamic processes governing water circulation actively influence suspended particle transport and deposition. In the estuarine mixing zone, the strong physico-chemical gradients resulting from the interaction between river freshwater and seawater may affect the distribution, mobility and fate of several potentially toxic compounds, among which trace elements are of major concern. Knowledge regarding the partitioning behaviour of trace elements would provide essential scientific support for the environmental management of estuaries. In this study, trace element occurrence and phase partitioning among suspended particulate matter, colloidal material and the truly dissolved fraction were investigated in the main Italian and Slovenian estuarine environments of the Gulf of Trieste (northern Adriatic Sea). Further information about the water quality at the river mouths was provided and, in addition to the traditional evaluation of single chemical parameters, a multi-way principal component analysis was employed in order to depict disparities among sampling sites, water layers and seasonal conditions with the final aim of evaluating trace element phase partitioning. Results indicated that the suspended particulate matter acts as the main effective vehicle for Cu, Cr, Fe, Ni and Pb, and enhanced adsorption processes resulted in elevated partitioning coefficients, especially for Fe and Pb. Although disparities occurred between sampling sites and seasons, trace elements showing affinity for the solid phase appeared to be partially bound to the colloidal material. Conversely, As and Cs prevailed in the truly dissolved fraction, especially in seawater and showed scarce affinity for both the suspended particles and colloids. Image 1 • Trace element partitioning behaviour among different fractions was investigated. • Trace elements appeared to be mainly partitioned in the suspended particles. • The truly dissolved fraction was found to be the dominant matrix for As and Cs. • MW-PCA is very effective in depicting disparities among different estuarine systems. [ABSTRACT FROM AUTHOR]

Dredging is a globally important aquatic system management activity, used for navigation improvement, contamination removal, aggregate production and/or flood risk mitigation. Despite widespread application, understanding of the environmental effects of some dredging types remains limited. Field campaigns in 2016 and 2017 in the River Parrett estuary, UK, therefore investigated the geomorphic and physicochemical effects of Water Injection Dredging (WID), a poorly studied hydrodynamic dredging technology. WID, applied to restore channel capacity for the maintenance of flood water conveyance in the tidal River Parrett, influenced surface elevations but not grain-size characteristics of dredged bed sediments. Topographic alterations due to the 2016 WID operation were short-lived, lasting less than 10 months, although benefits of the 2017 WID operation, in terms of volumetric change, outlasted the ≈12-month study period. Dredging had a significant impact on water physicochemistry (pH, dissolved oxygen, total suspended solids and turbidity) when comparing pre- and during-dredging conditions within the dredge reach, although time-series analysis found dredging effects were comparable in magnitude to tidal effects for some parameters. WID is typically targeted at the thalweg and not the banks, rendering the geomorphic signature of the method different to those of other, often more invasive dredging technologies (e.g. mechanical dredging methods). Further, thalweg not bankside dredging may have potential positive ecological implications, particularly where the majority of biomass is located within the channel margins, as in the tidal River Parrett. Collectively, data suggest WID can be an effective method for sediment dispersal within tidal systems although regular application may be required to maintain cross sectional areas, particularly where management precedes periods of low flows and/or high rates of sediment accumulation. In future, more work is required to better understand both the physical and ecological implications of WID as a flood risk management tool in estuaries and rivers. Image 1 • WID can be an effective method for sediment dispersal within tidal systems. • WID effects on channel topography can be short-lived, lasting less than 10 months. • WID targets the thalweg with potential positive implications for marginal habitats. • WID did not influence bed sediment grain-size distributions. • WID had a significant impact on water physicochemistry (pH, DO, TTS, turbidity). [ABSTRACT FROM AUTHOR]

Estuaries are cradles of life for the communities who live around and within them. They are valued in multiple ways for the services they provide to humans, including food production, recreation, water purification, navigation and amenity. Various groups of stakeholders all place different importance on these values, how their needs and practices interact, and what it means to effectively manage an estuary towards a range of desirable goals. This typically creates value conflicts over how estuaries should be managed. Navigating such conflicts requires governance arrangements and methods that allow multiple parties to find a common path forward. Using Evolutionary Governance Theory (EGT) and a hybrid analytic framework incorporating aspects of multi-level/multi-scalar governance, risk governance and territorial intelligence theory, this paper explores the (co-)evolution of governance processes by analysing lessons learnt from action in and observation of estuaries in Australia (Lower Hawkesbury), France (Thau) and New Caledonia (Thio). A multi-method research approach to data collection was used and comparative analysis across the three estuaries undertaken to understand the evolutions in each of their governance systems. From this analysis, several reflections and lessons for the governance of other land-sea systems emerge on: the importance of boundary organisations and boundary negotiations in re-defining integrated approaches to land-sea governance; how particular information systems or models, as well as discourses from other key actors shape co-evolutions of estuarine governance; and that risks or shocks still appear to be the catalysers of new forms of collective action and major reconfigurations and evolutions of estuarine governance. • Risks/shocks are principal catalysers of new forms of collective action and major reconfigurations of estuarine governance. • Boundary negotiations between actors and organisations are key in re-defining integrated approaches to land-sea governance. • Brokering organisations, information systems, models and discourses are non-human actors that shape governance co-evolutions. [ABSTRACT FROM AUTHOR]

Widespread land use change in coastal ecosystems has led to a decline in the amount of habitat available for fish and wildlife, lower production of ecosystem goods and services, and loss of recreational and aesthetic value. This has prompted global efforts to restore the natural hydrologic regimes of developed shorelines, especially resource-rich estuaries, but the resilience of these restored ecosystems in the face of accelerated sea-level rise (SLR) remains uncertain. We implemented a Mo nitoring-based S imulation of A ccretion i n C oastal E s tuaries (MOSAICS) in R statistical software to address uncertainty in the resilience of modified estuarine habitats, using the Nisqually River Delta in the Pacific Northwest USA as a case study. MOSAICS is a spatially explicit model with a numerical foundation that uses empirical monitoring datasets to forecast habitat change in response to rising tidal levels. Because it accounts for the crucial ecomorphodynamic feedbacks between tidal inundation, vegetative growth, and sediment accretion, MOSAICS can be used to determine whether alternative management scenarios, such as enhanced sediment inputs, will bolster estuarine resilience to SLR. Under moderate SLR (0.62 m), the model predicted that a two-fold increase in mean daily suspended sediment during the rainy season was sufficient to maintain Nisqually's emergent marshes through 2100, but under high SLR (1.35 m) MOSAICS indicated that greater sediment additions would be necessary to prevent submergence. A comparison between a restored marsh with subsided and high-elevation areas and a relict marsh demonstrated that the subsided restoration area was highly susceptible to SLR. Findings from the MOSAICS model highlight the importance of a site's initial elevation, capacity for producing above and belowground biomass, and suspended sediment availability when considering management actions in estuaries and other coastal ecosystems. [ABSTRACT FROM AUTHOR]

Adequate freshwater supply is vital to support the development of estuaries and deltas throughout the world. However, it is often threatened by saltwater intrusion, which results from the interaction of water and salt dynamics. A better understanding of estuarine dynamics is therefore critical in order to manage the effects of climate change and human interventions on estuarine ecosystem and freshwater resources. We focus here on a case study in the Pearl River Estuary (South China Sea), a region which has seen some of the most rapid urbanization in human history over the last forty years and which has become the largest contiguous urban region in the world. At present, saltwater intrusion endangers freshwater availability for over 40 million people, especially during the dry season. The Pearl River Estuary presents a complex shape, both in terms of bathymetry and geometry, making salt transport a three-dimensional process. Previous research on this estuary has mostly been limited to the longitudinal variability and non-time dependent forcing. In this study, we present results from a three-dimensional estuarine numerical model in order to unravel the interwoven longitudinal and lateral salt transport processes as well as their transient evolution. We implemented the FVCOM (Finite Volume Community Ocean Model) to the entire Pearl River Delta using an unstructured grid with a resolution ranging from about 200 km at the open ocean boundary to 20 m in the narrow channels in the upper reaches of the delta (allowing around five points across section). Numerical simulations cover the period from October 2007 to June 2008, thus focusing on the dry season and the onset of the monsoon and providing insight into the transient dynamics of the estuary. The bathymetry is generated from a set of surveys performed in 2008 in order to produce the most accurate representation of the delta at the time of the simulation. The model is forced by water elevation at the open ocean boundary. We specify freshwater inputs using daily measurement data from upstream hydrological stations. The initial and boundary salinity conditions are derived from outputs of the HYCOM model. The model is validated and calibrated against water level and salinity measurements available over the same time period. Numerical results from a series of numerical simulations presented here provide a detailed picture of the 3D salt dynamics both during time-independent conditions and during transient conditions. Early results show temporal variability at different scales, in particular with a dependence of salt intrusion length on spring-neap cycles. We will also present the influence of various forcing mechanisms, both individually and in conjunction with others. These results will help determine which conditions favour or inhibit the development of salt intrusion, as well as its sensitivity to the changes in those conditions. This knowledge will aid with estuary management and will help in identifying possible alleviating measures. [ABSTRACT FROM AUTHOR]

In spite of their perceived value, the widespread implementation of ecosystem services assessments has been limited because of perceptions of being too technical, too expensive, or requiring special expertise. For example, federal estuary management programs have widely used ecosystem services concepts to frame management issues and communicate with stakeholders. Yet, indicators assessed, monitored, and reported in estuarine management still have traditionally focused on ecological conditions, with weak connections, if any, to social or economic outcomes. Approaches are needed which expand the range of ecosystem services that can be considered, link ecosystem services explicitly to different stakeholder groups, facilitate effective communication with economists and other social scientists, and expand the array of available valuation techniques. We applied the concept of final ecosystem goods and services to review the broad suite of ecosystem services and their beneficiaries relevant to the management of two federal programs for estuary management, the National Estuary Program (NEP) and the National Estuarine Research Reserve System (NERRS). The Final Ecosystem Goods and Services Classification System provided a structured framework for connecting ecosystem services to their beneficiaries and the environments providing them. Document analysis of management plans assessed the degree to which these programs consider ecosystem services, their beneficiaries, and habitats within the estuarine watershed. The hierarchical list of final ecosystem goods and services generated from document analysis serves as a tool for defining management goals, identifying stakeholders, developing meaningful indicators, and conducting valuation studies in estuarine management planning efforts. Though developed here for estuarine management, the keyword hierarchy and final ecosystem goods and services approach have broad applicability and transferability to other environmental management scenarios.