Dissecting the ecosystem service of large-scale pollutant retention: The role of wetlands and other landscape features

Various features of a landscape contribute to the regulating ecosystem service of reducing waterborne pollutant loading to downstream environments. At local scales, wetlands have been shown to be effective in retaining pollutants. Here, we investigate the landscape-scale contribution to pollutant retention provided by multiple wetlands. We develop a general analytical model which shows that the retention contribution of wetlands and other landscape features is only significant if a large fraction of the total waterborne pollutant transport passes through them. Next, by means of a statistical analysis of official data, we quantify the nutrient retention contribution of wetlands for multiple sub-catchments in two Swedish Water Management Districts. We compare this with the retention contribution of two other landscape features: the waterborne transport distance and major lakes. The landscape-scale retention contribution of wetlands is undetectable; rather, the other two landscape features account for much of the total nutrient retention.     

Challenges to saving China’s freshwater biodiversity: Fishery exploitation and landscape pressures

China has over 1320 freshwater fish species, 877 of which are endemic. In recent decades, over-exploitation and landscape pressures have threatened them and led to a severe aquatic biodiversity crisis. In response, large-scale fishing bans have been promulgated to protect freshwater biodiversity in major Chinese rivers since the early 1980s. Here, we present the historical background and current challenges to the fishing bans. Implementing large-scale fishing bans may help improve China’s current freshwater biological resources and biodiversity to some extent. But implementing fishing bans alone is not sufficient to solve the crisis because of shortcomings of the current bans and expanding human pressures in most river basins. Thus, we recommend regulating other anthropogenic pressures, expanding duration and extent of current fishing regulations, establishing a comprehensive monitoring program, and initiating basin-scale ecological rehabilitation. These programs are also needed in other developing countries facing similar biodiversity crises and human pressures.     

Phoenix flagships: Conservation values and guanaco reintroduction in an anthropogenic landscape

Multiple forms of valuation contribute to public acceptance of conservation projects. Here, we consider how esthetic, intrinsic, and utilitarian values contribute to public attitudes toward a proposed reintroduction of guanaco (Lama guanicoe) in a silvopastoral system of central Chile. The nexus among landscape perceptions and valuations, support for reintroductions, and management of anthropogenic habitats is of increasing interest due to the proliferation of conservation approaches combining some or all of these elements, including rewilding and reconciliation ecology, for example. We assessed attitudes and values through an online questionnaire for residents of Santiago, Chile, using multiple methods including photo-montages and Likert scale assessments of value-based statements. We also combined the questionnaire approach with key informant interviews. We find strong support for the reintroduction of guanacos into the Chilean silvopastoral system (‘espinal’) in terms of esthetic and intrinsic values but less in terms of utilitarian values. Respondents preferred a scenario of espinal with guanacos and expressed interest in visiting it, as well as support for the reintroduction project on the basis that guanacos are native to central Chile. We suggest that reintroduced guanacos could serve as a ‘phoenix flagship species’ for espinal conservation, that is, a flagship species that has gone regionally extinct and is known but not associated with the region in the cultural memory. We consider how the lack of local cultural identity can both help and weaken phoenix flagships, which we expect to become more common.     

Late Holocene wetland transgression and 500 years of vegetation and fire variability in the semi-arid Amboseli landscape,southern Kenya

The semi-arid Amboseli landscape, southern Kenya, is characterised by intermittent groundwater-fed wetlands that form sedimentary geoarchives recording past ecosystem changes. We present a 5000-year environmental history of a radiocarbon dated sediment core from Esambu Swamp adjacent to Amboseli National Park. Although radiocarbon dates suggest an unconformity or sedimentary gap that spans between 3800 and 500 cal year BP, the record provides a unique insight into the long-term ecosystem history and wetland processes, particularly the past 500 years. Climatic shifts, fire activity and recent anthropogenic activity drive changes in ecosystem composition. Prior to 3800 cal year BP the pollen data suggest semi-arid savanna ecosystem persisted near the wetland. The wetland transgressed at some time between 3800 and 500 cal year BP and it is difficult to constrain this timing further, and palustrine peaty sediments have accumulated since 400 cal year BP. Increased abundance of Afromontane forest taxa from adjacent highlands of Kilimanjaro and the Chyulu Hills and local arboreal taxa reflect changes in regional moisture budgets. Particularly transformative changes occurred in the last five centuries, associated with increased local biomass burning coeval with the arrival of Maa-speaking pastoralists and intensification of the ivory trade. Cereal crops occurred consistently from around 300 cal year BP, indicative of further anthropogenic activity. The study provides unique insight in Amboseli ecosystem history and the link between ecosystem drivers of change. Such long-term perspectives are crucial for future climate change and associated livelihood impacts, so that suitable responses to ensure sustainable management practices can be developed in an important conservation landscape.     

The farmer as a landscape steward: Comparing local understandings of landscape stewardship,landscape values,and land management actions

We develop a landscape stewardship classification which distinguishes between farmers’ understanding of landscape stewardship, their landscape values, and land management actions. Forty semi-structured interviews were conducted with small-holder (<5 acres), medium-holders (5–100 acres), and large-holders (>100 acres) in South-West Devon, UK. Thematic analysis revealed four types of stewardship understandings: (1) an environmental frame which emphasized the farmers’ role in conserving or restoring wildlife; (2) a primary production frame which emphasized the farmers’ role in taking care of primary production assets; (3) a holistic frame focusing on farmers’ role as a conservationist, primary producer, and manager of a range of landscape values, and; (4) an instrumental frame focusing on the financial benefits associated with compliance with agri-environmental schemes. We compare the landscape values and land management actions that emerged across stewardship types, and discuss the global implications of the landscape stewardship classification for the engagement of farmers in landscape management.     

Assessment of heavy metal pollution in wetland soils from the young and old reclaimed regions in the Pearl River Estuary, South China

Soils were sampled in three types of wetlands from the young (A) and old (B) reclaimed regions of the Pearl River Estuary. They were analyzed for total concentrations of heavy metals to investigate their distributions and pollution levels in both regions. Results showed that most heavy metals in ditch and riparian wetlands did not significantly differ from those in reclaimed wetlands in A region, while significantly lower for Cd, Cu, Pb, and Zn in reclaimed wetlands in B region, suggesting higher effects of long-term reclamation. Iron, Cr and Cu were identified as metal pollutants of primary concern and had higher contributions to the total toxic units compared to other metals. Almost all metals exceeded their lowest effect levels and Fe and Cr even exceeded the severe effect levels. Multivariate analysis shows that Fe and Mn are controlled by parent rocks and other metals mainly originate from anthropogenic source.     

景观影响评价中"景观"的内涵和应用探讨

针对目前不同学科对于景观概念存在多种不同的解释,文章对环境影响评价中所基于的景观概念的内涵进行了探讨,指出了景观科学具有边缘性和开放性的特点。并根据目前中国景观影响评价的实际情况,提出了一些建议。     

Compromised metamorphosis and thyroid hormone changes in wood frogs (Lithobates sylvaticus) raised on reclaimed wetlands on the Athabasca oil sands

The wet landscape approach to oil sands tailings reclamation in the Athabasca Oil Sands region involves creating wetlands from fluid tailings in mined-out pits. We measured time to metamorphosis, thyroid hormone status, and detoxification enzyme (EROD) induction in Wood frog (Lithobates sylvaticus) tadpoles raised on reclaimed oil sands wetlands of different ages [young (≤7 yr) vs. old (>7 yr)] and compared data with tadpoles raised on reference (control) wetlands. Metamorphosis was delayed or never occurred in tadpoles raised in young tailings; those exposed to older tailings developed similarly to those in reference wetlands. Thyroid hormone disruption likely played an important role in the metamorphosis delay as the T3:T4 ratio was lowest in tadpoles raised in young, tailings-affected wetlands. Our findings suggest tailings wetlands become less toxic with age, and that these amphibians will be able to complete their life cycle in tailing wetlands that have sufficiently detoxified with age.     

Measurement, Collaborative Learning and Research for Sustainable Use of Ecosystem Services: Landscape Concepts and Europe as Laboratory

Policies at multiple levels pronounce the need to encompass both social and ecological systems in governance and management of natural capital in terms of resources and ecosystems. One approach to knowledge production and learning about landscapes as social–ecological systems is to compare multiple case studies consisting of large spaces and places. We first review the landscape concepts’ biophysical, anthropogenic, and intangible dimensions. Second, we exemplify how the different landscape concepts can be used to derive measurable variables for different sustainability indicators. Third, we review gradients in the three dimensions of the term landscape on the European continent, and propose to use them for the stratification of multiple case studies of social–ecological systems. We stress the benefits of the landscape concepts to measure sustainability, and how this can improve collaborative learning about development toward sustainability in social–ecological systems. Finally, analyses of multiple landscapes improve the understanding of context for governance and management.     

High-temporal resolution landscape changes related to anthropogenic activities over the past millennium in the Vosges Mountains (France)

Iron mining activities in the Bruche valley (Vosges Mountains, France) date historically from the Roman period to the mid-nineteenth century. The geochemical and palynological study of a core from the peat bog of Le Champ du Feu allows highlighting impacts of these activities over the past millennium. Trace metal contamination is recorded for lead (Pb), arsenic, zinc, and antimony during the Middle Ages, the sixteenth century, and from cal. ad 1750–1900, with several sources distinguished by Pb isotope analyses. Forest exploitation is attested by the palynological analysis of the core, with exploitation of Fagus for smelting processes and cutting of Abies for agro-pastoralism. This approach highlights several patterns of contamination, corresponding to the mixing sources and the contamination intensity, which can be linked to the pollen assemblage zones. Hence, anthropogenic activities such as mining and farming led to long-term modification of the landscape composition in this mountainous area.     

Wetlands as principal zones of methylmercury production in southern Louisiana and the Gulf of Mexico region

It is widely recognized that wetlands, especially those rich in organic matter and receiving appreciable atmospheric mercury (Hg) inputs, are important sites of methylmercury (MeHg) production. Extensive wetlands in the southeastern United States have many ecosystem attributes ideal for promoting high MeHg production rates; however, relatively few mercury cycling studies have been conducted in these environments. We conducted a landscape scale study examining Hg cycling in coastal Louisiana (USA) including four field trips conducted between August 2003 and May 2005. Sites were chosen to represent different ecosystem types, including: a large shallow eutrophic estuarine lake (Lake Pontchartrain), three rivers draining into the lake, a cypress-tupelo dominated freshwater swamp, and six emergent marshes ranging from a freshwater marsh dominated by Panicum hemitomon to a Spartina alterniflora dominated salt marsh close to the Gulf of Mexico. We measured MeHg and total Hg (THg) concentrations, and ancillary chemical characteristics, in whole and filtered surface water, and filtered porewater. Overall, MeHg concentrations were greatest in surface water of freshwater wetlands and lowest in the profundal (non-vegetated) regions of the lake and river mainstems. Concentrations of THg and MeHg in filtered surface water were positively correlated with the highly reactive, aromatic (hydrophobic organic acid) fraction of dissolved organic carbon (DOC). These results suggest that DOC plays an important role in promoting the mobility, transport and bioavailability of inorganic Hg in these environments. Further, elevated porewater concentrations in marine and brackish wetlands suggest coastal wetlands along the Gulf Coast are key sites for MeHg production and may be a principal source of MeHg to foodwebs in the Gulf of Mexico. Examining the relationships among MeHg, THg, and DOC across these multiple landscape types is a first step in evaluating possible links between key zones for Hg(II)-methylation and the bioaccumulation of mercury in the biota inhabiting the Gulf of Mexico region.     

Abrupt biological response to hydrologic and land-use changes in Lake Apopka, Florida, USA

Lake Apopka is a shallow, hypereutrophic lake in north-central Florida that experienced an abrupt shift in primary producer community structure (PPCS) in 1947. The PPCS shift was so abrupt anecdotal accounts report that dominant, submersed aquatic vegetation was uprooted by a hurricane in 1947 and replaced by phytoplankton within weeks. Here we propose two hypotheses to explain the sudden shift to phytoplankton. First, hydrologic modification of the drainage basin in the late 1800s lowered the lake level ca. 1.0 m, allowing the ecosystem to accommodate moderate, anthropogenic nutrient enrichment through enhanced production in the macrophyte community. Second, additional hydrologic changes and large-scale agricultural development of floodplain wetlands began in 1942 and altered the pattern and scale of phosphorus loading to the lake that triggered the rapid shift to phytoplankton dominance in 1947. Historic land-use changes and paleolimnological data on biological responses to nutrient loading support these hypotheses.     

Modeling the long-term transport and accumulation of radionuclides in the landscape for derivation of dose conversion factors

To evaluate the radiological impact of potential releases to the biosphere from a geological repository for spent nuclear fuel, it is necessary to assess the long-term dynamics of the distribution of radionuclides in the environment. In this paper, we propose an approach for making prognoses of the distribution and fluxes of radionuclides released from the geosphere, in discharges of contaminated groundwater, to an evolving landscape. The biosphere changes during the temperate part (spanning approximately 20,000 years) of an interglacial period are handled by building biosphere models for the projected succession of situations. Radionuclide transport in the landscape is modeled dynamically with a series of interconnected radioecological models of those ecosystem types (sea, lake, running water, mire, agricultural land and forest) that occur at present, and are projected to occur in the future, in a candidate area for a geological repository in Sweden. The transformation between ecosystems is modeled as discrete events occurring every thousand years by substituting one model by another. Examples of predictions of the radionuclide distribution in the landscape are presented for several scenarios with discharge locations varying in time and space. The article also outlines an approach for estimating the exposure of man resulting from all possible reasonable uses of a potentially contaminated landscape, which was used for derivation of Landscape Dose Factors.     

滨河湿地对农业非点源氮污染控制研究进展

氮素是农业径流最重要、最普遍的水体污染物。滨河湿地因受到陆地生境和水生生境双重影响而显得非常独特,作为重要的陆地和水生环境的生态交错带,滨河湿地能够阻断和改变水运污染物,特别是农业径流中的氮排入临近的小溪和河流。植物吸收和反硝化作用是滨河湿地两种最重要的截留和缓解氮负荷的有效途径,氮素可以通过生物转化、植物吸收、微生物暂时固氮等方式去除,但是永久性的去除氮却是通过反硝化过程来完成的。为了系统认识和了解滨河湿地生态系统对农业非点源氮污染控制过程,通过大量文献分析讨论了滨河湿地对农业非点源氮的净化能力、净化机制及其影响因素,并结合我国研究现状展望了该领域的研究前景。滨河湿地对农业非点源氮污染的控制作用研究将成为滨河湿地生态系统服务功能评价、滨河湿地生态系统健康与稳定的诊断和退化滨河湿地生态系统修复的重要基础理论。     

Desert locust control in ecologically sensitive areas: need for guidelines

Chemical control of desert locust (DL) is carried out over large areas of land, covering a range of different landscapes and ecosystems. There are no real restrictions for spraying in or close to environmentally sensitive areas and awareness of sensitivity is not always obvious to the people involved in control. However, concern about environmental issues in connection with DL control is growing and clear guidelines are needed. The objectives were: to identify and delineate areas particularly sensitive to pesticide contamination in northeastern Africa, e.g. protected areas, wetlands, populated places, oases, and areas with concentrations of migratory birds. These areas were matched with actual DL control during 1986-1998. The conclusion is that chemical control occurred in environmentally sensitive areas especially wetlands, e.g. temporary waters and mangroves; close to human settlements; and, to some extent, in or near protected areas and areas with numerous migratory birds.     

Particle deposition,resuspension and phosphorus accumulation in small constructed wetlands

To improve understanding of phosphorus (P) retention processes in small constructed wetlands (CWs), we analysed variations in sediment deposition and accumulation in four CWs on clay soils in east-central Sweden. Sediment deposition (in traps) generally exceeded the total suspended solids (TSS) load suggesting that resuspension and wetland base erosion were important. This was confirmed by quantification of particle accumulation (on plates) (1–23 kg m^?2 year^?1), which amounted to only 13–23% of trap deposition. Spatial mean P concentrations in accumulated sediment on plates (0.09–0.15%) were generally similar to temporal mean P concentrations of particles in water (0.11–0.15%). Deposition/accumulation was minor in one wetland with high hydraulic load (400 m year^?1), suggesting that such small wetlands are not efficient as particle sinks. Economic support for CWs are given, but design and landscape position are here demonstrated to be important for effective P retention.     

复合型絮凝剂处理景观水体

利用以生物絮凝剂(1 g/L MBF-28)与化学絮凝剂(5 g/L PAC)复配后的复合絮凝剂CBF28C处理景观水体,考虑了复配比、投加量、pH和投加顺序对处理景观水的影响。实验结果表明:对于反应体系为100 mL景观水体,当MBF-28与PAC溶液复配体积比为3∶1,反应体系pH为7.0,1 mL 1%CaCl2作助凝剂,1.5 mL CBF28C时,其絮凝效果最好,其COD,色度,TN,TP的去除率分别为90.7%,54.1%、46.6%和51.5%。最佳水力条件为:快速320 r/min,快搅时间45 s,慢速80 r/min,慢搅时间100 s。并且得出了前10 min内絮凝率的反应关系方程式。     

Study on habitat suitability of overwintering cranes based on landscape pattern change—a case study of typical lake wetlands in the middle and lower reaches of the Yangtze River

Shengjin Lake wetland is located in the middle and lower reaches of the Yangtze River in China. It is a typical lake-type wetland and is also an ideal place for rare cranes to overwintering. The changes of wetland landscape are closely related to the habitat quality of wintering cranes. It is of great significance to study the habitat change of wintering cranes in wetland for wetland ecological restoration and restoration. In this paper, we analyze four kinds of winter cranes and wetland landscape pattern types from the years 1986 to 2015. Also, we adopted the Pearson correlation analysis method to analyze the relationship between wetland landscape types and crane population, and the main landscape types of cranes habitat were obtained. We selected disturbance degree, food richness, vegetation cover, and hydrological condition as the main factors affecting wintering habitat of cranes. We established a habitat suitability index model for wintering cranes and generated habitat suitability assessment maps by ArcGIS. The results show that the change of landscape pattern in Shengjin Lake protected area was obvious, the number of wetland patches increased, the fragmentation degree of landscape increased, the landscape patch difference became smaller, and the diversity index and evenness index increased gradually. From 1986 to 2015, the number of wintering cranes decreased and the habitat suitability index of wintering cranes decreased from 0.845 to 0.465, and the habitat suitability of wintering cranes fell from 13,577.11 to 7424.42 ha, which showed the overall habitat deteriorated significantly and had a positive correlation between the crane population and habitat suitability.

     

低动力复合净水系统净化生态农庄景观池水质

采用生物填料、阿科蔓生态基和生态浮盆等材料构建低动力复合净水系统(LCWPS)进行生态农庄人工景观池水质净化技术示范研究。系统稳定运行后的周年监测结果表明,整体系统使人工景观池的CODMn、TN、NH4+-N、TP和浊度分别下降61.1%～62.8%、36.0%～39.9%、14.3%～35.7%、66.7%～79.5%和76.8%～79.8%,水质溶解氧浓度(DO)上升72.7%～126.0%,景观池水质达到《地表水环境质量标准》(GB3838-2002)中景观水域需要的V类水质标准,并能长期保持稳定。从管理维护成本角度考虑,利用LCWPS净化生态农庄人工景观池水质能达到节能节水的目的。