Coastal Environmental Impacts Brought About by Alterations to Freshwater Flow in the Gulf of Mexico

/ Freshwater inflow is one of the most influential landscape processes affecting community structure and function in lagoons, estuaries, and deltas of the world; nevertheless there are few reviews of coastal impacts associated with altered freshwater inputs. A conceptual model of the possible influences of freshwater inflows on biogeochemical and trophic interactions was used to structure this review, evaluate dominant effects, and discuss tools for coastal management. Studies in the Gulf of Mexico were used to exemplify problems commonly encountered by coastal zone managers and scientists around the world. Landscape alteration, impacting the timing and volume of freshwater inflow, was found to be the most common stress on estuarine systems. Poorly planned upstream landscape alterations can impact wetland and open-water salinity patterns, nutrients, sediment fertility, bottom topography, dissolved oxygen, and concentrations of xenobiotics. These, in turn, influence productivity, structure, and behavior of coastal plant and animal populations. Common biogeochemical impacts include excessive stratification, eutrophication, sediment deprivation, hypoxia, and contamination. Common biological impacts include reduction in livable habitats, promotion of "exotic" species, and decreased diversity. New multiobjective statistical models and dynamic landscape simulations, used to conduct policy-relevant experiments and integrate a wide variety of coastal data for freshwater inflow management, assume that optimum estuarine productivity and diversity is found somewhere between the stress associated with altered freshwater flow and the subsidy associated with natural flow. These models attempt to maximize the area of spatial overlap where favorable dynamic substrates, such as salinity, coincide with favorable fixed substrates, such as bottom topography. Based upon this principle of spatial overlap, a statistical performance model demonstrates how population vitality measurements (growth, survival, and reproduction) can be used to define sediment, freshwater, and nutrient loading limits. Similarly, a spatially articulate landscape simulation model demonstrates how cumulative impacts and ecosystem processes can be predicted as a function of changes in freshwater, sediment, and nutrient inflows.KEY WORDS: Resource management; Landscape impacts; Freshwater discharge; Coastal, ecosystem models; Coastal wetlands     

Human Impacts on Land Cover and Water Balances in a Coastal Mediterranean County

We analyzed the effects of changes in land cover on the water balance in Spain’s Marina Baixa County, on the Mediterranean coast. To reveal how different land management strategies have affected the area’s environment, four municipalities within the same catchment were studied: Benidorm, Callosa d’en Sarrià, Beniardà, and Guadalest. In the municipalities of Callosa and Benidorm, the proportion of the area covered by woodland declined by 4.2% and 30.2%, respectively, and woodland was replaced by agriculture and urban development. The abandonment of farmland produced a 17% increase in the proportion of the area covered by vegetation in Guadalest and Beniardá, where frequent forest fires have exacerbated a decrease in the area of pine woodland. Tourism development in Benidorm has been accompanied by an increase in the transportation infrastructure and by an expansion of areas with an impermeable surface, with the lowest level of infiltration into the aquifer system. These changes have generated a net water deficit in Callosa and Benidorm of more than 6 Mm³/year, creating a high demand for water imported from other municipalities (Guadalest and Beniardá) or from outside of the county to maintain the sustainability of the current water management strategies. The Marina Baixa case study is representative of many of the world’s coastal areas that are undergoing rapid urban development based on an inappropriate understanding of human progress based mainly on economic development and thus provides insights into water management in other areas.     

Minimizing Impacts of Maintenance Dredged Material Disposal in the Coastal Environment: A Habitat Approach

At present, coastal disposal of maintenance dredged material constitutes one of the most important problems in coastal zone management and in some coastal areas represents the major anthropogenic disturbance to the benthos. In this review we first propose, based on the classic literature, that macrofaunal communities typical of environmentally stressed habitats are more resilient than those of more environmentally stable habitats, and we outline the macrofaunal successional changes following a disturbance. Second, from a review and analysis of the published and unpublished literature on macrofaunal recovery following maintenance dredged material deposition in the coastal environment, we compare the successional sequences and recovery rates in euhaline and polyhaline systems. The review reveals that invertebrate recovery following dredged material disposal in relatively unstressed marine environments generally takes between 1 and 4 years, while in more naturally stressed areas, recovery is generally achieved within 9 months, although deeper polyhaline habitats can take up to 2 years to recover. Differences in recovery times are attributed to the number of successional stages required to regain the original community composition and that species typical of naturally unstressed assemblages do not possess life-history traits to allow rapid recolonization of disturbances. In the last section of this review, the management implications of these findings are discussed in terms of minimizing dredged material disposal impacts on fisheries resources. Since the natural disturbance regime appears to be very important in determining the response of a benthic community following dredged material disposal, it is recommended that when predicting the potential environmental impact of an operation, the nature of the physical environment in combination with the status (and role) of associated marine benthic communities should be considered.     

Headwater Influences on Downstream Water Quality

We investigated the influence of riparian and whole watershed land use as a function of stream size on surface water chemistry and assessed regional variation in these relationships. Sixty-eight watersheds in four level III U.S. EPA ecoregions in eastern Kansas were selected as study sites. Riparian land cover and watershed land use were quantified for the entire watershed, and by Strahler order. Multiple regression analyses using riparian land cover classifications as independent variables explained among-site variation in water chemistry parameters, particularly total nitrogen (41%), nitrate (61%), and total phosphorus (63%) concentrations. Whole watershed land use explained slightly less variance, but riparian and whole watershed land use were so tightly correlated that it was difficult to separate their effects. Water chemistry parameters sampled in downstream reaches were most closely correlated with riparian land cover adjacent to the smallest (first-order) streams of watersheds or land use in the entire watershed, with riparian zones immediately upstream of sampling sites offering less explanatory power as stream size increased. Interestingly, headwater effects were evident even at times when these small streams were unlikely to be flowing. Relationships were similar among ecoregions, indicating that land use characteristics were most responsible for water quality variation among watersheds. These findings suggest that nonpoint pollution control strategies should consider the influence of small upland streams and protection of downstream riparian zones alone is not sufficient to protect water quality.     

Framework for Measuring Sustainable Development in Catchment Systems

Integrated catchment management represents an approach to managing the resources of a catchment by integrating environmental, economic, and social issues. It is aimed at deriving sustainable benefits for future generations, while protecting natural resources, particularly water, and minimizing possible adverse social, economic, and environmental consequences. Indicators of sustainable development, which summarize information for use in decision-making, are invaluable when trying to assess the diverse, interacting components of catchment processes and resource management actions. The Driving-Forces–Pressure–State–Impact–Response (DPSIR) indicator framework is useful for identifying and developing indicators of sustainable development for catchment management. Driving forces have been identified as the natural conditions occurring in a catchment and the level of development and economic activity. Pressures include the natural and anthropogenic supply of water, water demand, and water pollution. State indicators can be split into those of quantity and those of quality. Impacts include those that affect the ecosystems directly and those that impact the use value of the resource. It core indicators are identified within each of the categories given in the framework, most major catchment-based management issues can be evaluated. This framework is applied to identify key issues in catchment management in South Africa, and develop a set of indicators for evaluating catchments throughout the country.     

Human Influences on Water Quality in Great Lakes Coastal Wetlands

A better understanding of relationships between human activities and water chemistry is needed to identify and manage sources of anthropogenic stress in Great Lakes coastal wetlands. The objective of the study described in this article was to characterize relationships between water chemistry and multiple classes of human activity (agriculture, population and development, point source pollution, and atmospheric deposition). We also evaluated the influence of geomorphology and biogeographic factors on stressor-water quality relationships. We collected water chemistry data from 98 coastal wetlands distributed along the United States shoreline of the Laurentian Great Lakes and GIS-based stressor data from the associated drainage basin to examine stressor-water quality relationships. The sampling captured broad ranges (1.5–2 orders of magnitude) in total phosphorus (TP), total nitrogen (TN), dissolved inorganic nitrogen (DIN), total suspended solids (TSS), chlorophyll a (Chl a), and chloride; concentrations were strongly correlated with stressor metrics. Hierarchical partitioning and all-subsets regression analyses were used to evaluate the independent influence of different stressor classes on water quality and to identify best predictive models. Results showed that all categories of stress influenced water quality and that the relative influence of different classes of disturbance varied among water quality parameters. Chloride exhibited the strongest relationships with stressors followed in order by TN, Chl a, TP, TSS, and DIN. In general, coarse scale classification of wetlands by morphology (three wetland classes: riverine, protected, open coastal) and biogeography (two ecoprovinces: Eastern Broadleaf Forest [EBF] and Laurentian Mixed Forest [LMF]) did not improve predictive models. This study provides strong evidence of the link between water chemistry and human stress in Great Lakes coastal wetlands and can be used to inform management efforts to improve water quality in Great Lakes coastal ecosystems.     

Methodological Development of an Index of Coastal Water Quality: Application in a Tourist Area

With the aim of obtaining an index of coastal water quality, a methodological procedure based on numerical classification and discriminant analysis is presented. The procedure was applied to nutrient data (ammonia, nitrite, nitrate, and phosphate) analyzed along the coastal waters of a Spanish tourist area. Using numerical classification, three levels of nutrient loading were revealed, characterizing oligotrophic, mesotrophic, and potentially eutrophic waters. Discriminant analysis was shown to be an effective methodological tool in the discrimination between trophic groups. For every group, the discriminant procedure generated the centroids. The centroids representing oligotrophic and potentially eutrophic conditions were used to establish the two extremes of the continuum of mesotrophic conditions in these coastal waters: Standardizing values from -1 to 1, the centroids for oligotrophic and potentially eutrophic waters yielded an interval that defined the range of mesotrophic conditions. This interval is proposed as a water quality index. The ability of the coastal water quality index to successfully predict mesotrophic conditions was proved with random samples.     

Impact of 100-Year Human Interventions on the Deltaic Coastal Zone of the Inner Thermaikos Gulf (Greece): A DPSIR Framework Analysis

The Axios River delta and the Inner Thermaikos Gulf coastal zone have experienced a long period of human interventions during the past 100 years. A post-evaluation of long run coastal zone changes under the Drivers-Pressures-State-Impacts-Response (DPSIR) conceptual framework is presented. The DPSIR approach is then used to project out into possible futures in order to connect with policy and management options proposed for the improvement of the current conditions and the achievement of sustainable development, in the coastal zone. Socio-economic driving forces with their origins in the end of the 19^th century have generated numerous pressures in the coastal environment that changed the state of the environment. In the first part of the last century, there was no coupling between change of state and policy. Due to increasing environmental awareness, a coupling became more apparent over the last thirty years. Human interventions include river route realignment, extensive drainage of the plains, irrigation network, roads and dam constructions. The consequences were positive for the economic development of the area, human health, and navigation for the port of Thessaloniki. In contrast, the manipulation and over-use of natural resources has led to a reduction of wetlands, biodiversity loss, stress on freshwater supplies, and subsidence of coastal areas, aquifer salinization, and rapid coastal erosion. Three plausible future scenarios are utilised in order to investigate the implications of this environmental change process and possible socio-economic consequences.     

Hydrological and Oceanographic Considerations for Integrated Coastal Zone Management in Southern Belize

9 m³, a volume equal to the basin. During the rainy season, June–September, 84% of the annual discharge occurs, which causes the bay to become brackish. Port Honduras serves as an important nursery ground for many species of commercially important fish and shellfish. The removal of forest cover in the uplands, as a result of agriculture, aquaculture, and village development, is likely to significantly accelerate erosion. Increased erosion would reduce soil fertility in the uplands and negatively affect mangrove, seagrass, and coral reef productivity in the receiving coastal embayment. Alternatively, the conservation of an existing protected areas corridor, linking the Maya Mountains to the Caribbean Sea, is likely to enhance regional sustainable economic development. This study aims to support environmental management at the scale of the “ecoscape”—a sensible ecological unit of linked watersheds and coastal and marine environments.     

Remote Sensing of Landscape-Level Coastal Environmental Indicators

Advances in technology and decreases in cost are making remote sensing (RS) and geographic information systems (GIS) practical and attractive for use in coastal resource management. They are also allowing researchers and managers to take a broader view of ecological patterns and processes. Landscape-level environmental indicators that can be detected by Landsat Thematic Mapper (TM) and other remote sensors are available to provide quantitative estimates of coastal and estuarine habitat conditions and trends. Such indicators include watershed land cover, riparian buffers, shoreline and wetland changes, among others. With the launch of Landsat 7, the cost of TM imagery has dropped by nearly a factor of 10, decreasing the cost of monitoring large coastal areas and estuaries. New satellites, carrying sensors with much finer spatial (1-5 m) and spectral (200 narrow bands) resolutions are being launched, providing a capability to more accurately detect changes in coastal habitat and wetland health. Advances in the application of GIS help incorporate ancillary data layers to improve the accuracy of satellite land-cover classification. When these techniques for generating, organizing, storing, and analyzing spatial information are combined with mathematical models, coastal planners and managers have a means for assessing the impacts of alternative management practices.     

Water Quality in the Near Coastal Waters of the Gulf of Mexico Affected by Hurricane Katrina: Before and After the Storm

Water quality was assessed following Hurricane Katrina in the affected waters of Alabama, Mississippi, and Louisiana. Post-landfall water quality was compared to pre-hurricane conditions using indicators assessed by EPA’s National Coastal Assessment program and additional indicators of contaminants in water and pathogens. Water quality data collected after Hurricane Katrina suggest that the coastal waters affected by the storm exhibited higher salinity and concentrations of chlorophyll a, dissolved inorganic phosphorus, and total suspended solids following the storm compared to the previous 5-year averages. Higher bottom dissolved oxygen concentrations and light attenuation were also observed. Contaminant concentrations measured in the water column were very low or undetectable, as were the presence of pathogens. Overall water quality did not significantly differ from water quality assessed in the five years preceding the storm. Statistical analyses indicate that use of a probabilistic survey design is appropriate for making pre-storm and post storm comparisons for water quality condition on an areal basis. The information in this article has been funded wholly (or in part) by the U.S. Environmental Protection Agency. It has been subjected to review by the National Health and Environmental Effects Research Laboratory and approved for publication. Approval does not signify that the contents reflect the views of the Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. This is contribution number 1280 from the Gulf Ecology Division.     

辽宁沿海经济带滨海湿地资源的开发与保护研究

辽宁省拥有丰富多样的滨海湿地资源.随着辽宁沿海经济带升级为国家战略,滨海湿地资源将面临不同程度的开发影响.从辽宁滨海湿地资源禀赋与开发现状人手,分析了滨海湿地资源开发与保护中存在的主要问题,探讨了滨海湿地在沿海经济带开发中的重要功能与地位,并提出实现滨海湿地资源可持续开发利用的对策建议.     

Modeling the Impacts of Farming Practices on Water Quality in the Little Miami River Basin

Since intensive farming practices are essential to produce enough food for the increasing population, farmers have been using more inorganic fertilizers, pesticides, and herbicides. Agricultural lands are currently one of the major sources of non-point source pollution. However, by changing farming practices in terms of tillage and crop rotation, the levels of contamination can be reduced and the quality of soil and water resources can be improved. Thus, there is a need to investigate the amalgamated hydrologic effects when various tillage and crop rotation practices are operated in tandem. In this study, the Soil Water Assessment Tool (SWAT) was utilized to evaluate the individual and combined impacts of various farming practices on flow, sediment, ammonia, and total phosphorus loads in the Little Miami River basin. The model was calibrated and validated using the 1990–1994 and 1980–1984 data sets, respectively. The simulated results revealed that the SWAT model provided a good simulation performance. For those tested farming scenarios, no-tillage (NT) offered more environmental benefits than moldboard plowing (MP). Flow, sediment, ammonia, and total phosphorus under NT were lower than those under MP. In terms of crop rotation, continuous soybean and corn–soybean rotation were able to reduce sediment, ammonia, and total phosphorus loads. When the combined effects of tillage and crop rotation were examined, it was found that NT with continuous soybean or corn–soybean rotation could greatly restrain the loss of sediments and nutrients to receiving waters. Since corn–soybean rotation provides higher economic revenue, a combination of NT and corn–soybean rotation can be a viable system for successful farming.     

基于多中心理论的辽宁沿海经济带环境治理模式研究

辽宁沿海经济带是我国沿海地区生态环境较为脆弱的地区之一,环境污染和破坏问题较突出。而环境治理直接关系到经济与社会的持续发展,环境治理模式则是决定环境治理绩效的重要因素之一。运用多中心模式分析辽宁沿海经济带环境治理存在的问题及其原因,构建该区域的多中心治理模式,并在此基础上提出相应的策略措施,为辽宁省沿海经济带发展规划的实施提供参考。     

Glocalization of COVID-19 responses and management of the pandemic in Africa

ABSTRACT

The study explores how glocalization of COVID-19 responses affects the management of the pandemic in Africa. Using data from 20 selected African countries, the study found that the reliance on local medicines alongside other salient global initiatives for containment of COVID-19 is effective in managing the pandemic in Africa. It concluded that despite the high vulnerabilities of African countries to COVID-19, the glocal approach has yielded positive outcomes by increasing the number of patients that recover from COVID-19 and scaling down the fatalities compared with the other regions.     

Impacts of Off-Road Vehicles (ORVs) on Macrobenthic Assemblages on Sandy Beaches

Sandy beaches are the prime sites for human recreation and underpin many coastal economies and developments. In many coastal areas worldwide, beach recreation relies on the use of off-road vehicles (ORVs) driven on the shore. Yet, the use of ORVs is not universally embraced due to social conflicts with other beach user groups and putative environmental consequences of vehicle traffic on sandy shores. Such ecological impacts of ORVs are, however, poorly understood for endobenthic invertebrates of the intertidal zone seawards of the dunes. Consequently, this study quantified the degree to which assemblages of intertidal beach invertebrates are affected by traffic. The study design comprised a series of temporally replicated spatial contrasts between two reference sites (no ORVs) and two beaches with heavy ORV traffic (in excess of 250,000 vehicles per year) located in South-East Queensland, Australia. Macrobenthic assemblages on ORV-impacted beaches had significantly fewer species at substantially reduced densities, resulting in marked shifts in community composition and structure. These shifts were particularly strong on the middle and upper shore where vehicle traffic was concentrated. Strong effects of ORVs were detectable in all seasons, but increased towards the summer months as a result of heavier traffic volumes. This study provides clear evidence that ORVs can have substantial impacts on sandy beach invertebrates that are manifested throughout the whole community. Demonstrating such an ecological impact caused by a single type of human use poses a formidable challenge to management, which needs to develop multi-faceted approaches to balance environmental, social, cultural, and economic arguments in the use of sandy shores, including management of “beach traffic.”     

Framework and Tools for Agricultural Landscape Assessment Relating to Water Quality Protection

While many scientific studies show the influence of agricultural landscape patterns on water cycle and water quality, only a few of these have proposed scientifically based and operational methods to improve water management. Territ’eau is a framework developed to adapt agricultural landscapes to water quality protection, using components such as farmers’ fields, seminatural areas, and human infrastructures, which can act as sources, sinks, or buffers on water quality. This framework allows us to delimit active areas contributing to water quality, defined by the following three characteristics: (i) the dominant hydrological processes and their flow pathways, (ii) the characteristics of each considered pollutant, and (iii) the main landscape features. These areas are delineated by analyzing the flow connectivity from the stream to the croplands, by assessing the buffer functions of seminatural areas according to their flow pathways. Hence, this framework allows us to identify functional seminatural areas in terms of water quality and assess their limits and functions; it helps in proposing different approaches for changing agricultural landscape, acting on agricultural practices or systems, and/or conserving or rebuilding seminatural areas in controversial landscapes. Finally, it allows us to objectivize the functions of the landscape components, for adapting these components to new environmental constraints.     

Assessment of Economic and Water Quality Impacts of Land Use Change Using a Simple Bioeconomic Model

The objective of this study is to assess the economic and water quality impact of land use change in a small watershed in the Wiregrass region of Alabama. The study compares changes in water quality and revenue from agricultural and timber production due to changes in land use between years 1992 and 2001. The study was completed in two stages. In the first stage, a biophysical model was used to estimate the effect of land use change on nitrogen and phosphorus runoff and sediment deposition in the main channel; in the second stage, farm enterprise budgeting tools were used to estimate the economic returns for the changes in land use condition. Both biophysical and economic results are discussed, and a case for complex optimization to develop a decision support system is presented.     

加强水资源的系统管理

我国是一个水资源十分短缺的国家，加强水资源管理刻不容缓。为此，本文结合我国水资源管理的实际状况，从思想、组织、方法、手段等方面分别论述了加强水资源系统管理的必要性和可能性。     

An Ecological and Economic Assessment Methodology for Coastal Ecosystem Management

An adaptation of the Drivers-Pressure-State-Impact-Response methodology is presented in this work. The differential DPSIR (ΔDPSIR) was developed to evaluate impacts on the coastal environment and as a tool for integrated ecosystem management. The aim of the ΔDPSIR is to provide scientifically-based information required by managers and decision-makers to evaluate previously adopted policies, as well as future response scenarios. The innovation of the present approach is to provide an explicit link between ecological and economic information related to the use and management of a coastal ecosystem within a specific timeframe. The application of ΔDPSIR is illustrated through an analysis of developments in a Southwest European coastal lagoon between 1985 and 1995. The value of economic activities dependent on the lagoon suffered a significant reduction (ca. −60%) over that period, mainly due to a decrease in bivalve production. During that decade the pressures from the catchment area were managed (ca. 176 million Euros), mainly through the building of waste water treatment plants. Notwithstanding this, the ecosystem state worsened with respect to abnormal clam mortalities due to a parasite infection and to benthic eutrophication symptoms in specific problematic areas. The negative economic impacts during the decade were estimated between −565 and −315 million Euros, of which 9–49% represent the cost of environmental externalities. Evaluation of these past events indicates that future management actions should focus on reducing the limitation on local clam seeds, which should result in positive impacts to both the local socio-economy and biodiversity.