The use of fish parasites as biological indicators of anthropogenic influences in coral-reef lagoons: a case study of Apogonidae parasites in New-Caledonia

Parasite species have been widely used as fish host migration tag or as indicators of local pollution. In this paper our approach is to consider the entire parasite community as a biological indicator of the fish environmental conditions. Seven fish species belonging to the Apogonidae, Apogon bandanensis, A. cookii, A. doderleini, A. norfolkensis, A. trimaculatus, Cheilodipterus quinquelineatus and Fowleria variegata, were sampled on six stations in two bays (Grand-Rade and Sainte-Marie) around Nouméa (New-Caledonia). The two bays are submitted to urban wastewater inputs alone or combined with additional industrial inputs which influences decrease from the inner part to the entrance of each bay. A total of 592 fish were dissected for macro parasite examination. Parasites were grouped according to their taxonomical rank and development stage for the analysis. We found an inconsistent effect of the confinement between the two bays, revealing that the parasite community is not the same in the two bays. Moreover, the encysted metacercariae found in the pericardic cavity were found to be significant indicators of the specific anthropogenically impacted environmental conditions prevailing in the inner parts of the two bays. Other parasite taxa were found to be significant indicators of specific environmental conditions in one or two stations among the six sampled. Results on parasite specificity and biological life cycle of the parasite taxa found in sampled Apogonid were further compared with environmental parameters.     

Changes in event-based streamflow magnitude and timing after suburban development with infiltration-based stormwater management

Green stormwater infrastructure implementation in urban watersheds has outpaced our understanding of practice effectiveness on streamflow response to precipitation events. Long-term monitoring of experimental suburban watersheds in Clarksburg, Maryland, USA, provided an opportunity to examine changes in event-based streamflow metrics in two treatment watersheds that transitioned from agriculture to suburban development with a high density of infiltration-focused stormwater control measures (SCMs). Urban Treatment 1 has predominantly single family detached housing with 33% impervious cover and 126 SCMs. Urban Treatment 2 has a mix of single family detached and attached housing with 44% impervious cover and 219 SCMs. Differences in streamflow-event magnitude and timing were assessed using a before-after-control-reference-impact design to compare urban treatment watersheds with a forested control and an urban control with detention-focused SCMs. Streamflow and precipitation events were identified from 14 years of sub-daily monitoring data with an automated approach to characterize peak streamflow, runoff yield, runoff ratio, streamflow duration, time to peak, rise rate, and precipitation depth for each event. Results indicated that streamflow magnitude and timing were altered by urbanization in the urban treatment watersheds, even with SCMs treating 100% of the impervious area. The largest hydrologic changes were observed in streamflow magnitude metrics, with greater hydrologic change in Urban Treatment 2 compared with Urban Treatment 1. Although streamflow changes were observed in both urban treatment watersheds, SCMs were able to mitigate peak flows and runoff volumes compared with the urban control. The urban control had similar impervious cover to Urban Treatment 2, but Urban Treatment 2 had more than twice the precipitation depth needed to initiate a flow response and lower median peak flow and runoff yield for events less than 20 mm. Differences in impervious cover between the Urban Treatment watersheds appeared to be a large driver of differences in streamflow response, rather than SCM density. Overall, use of infiltration-focused SCMs implemented at a watershed-scale did provide enhanced attenuation of peak flow and runoff volumes compared to centralized-detention SCMs.     

Bioretention planter performance measured by lag and capture

Bioretention flow-through planters manage stormwater with smaller space requirements or structural constraints associated with other forms of green infrastructure. This project monitored the hydrology of four bioretention planters at Stevens Institute of Technology to evaluate the system's ability to delay runoff and fully capture small rain events. The water depth in the outflow and the volumetric water content near the inflow were measured continuously over 15 months. Rainfall characteristics were documented from an on-site rain gauge. This monitoring determined the time from the start of a rain event to the onset of outflow from each planter, which was defined as the lag. The initial moisture deficit (difference between pre-event volumetric water content and maximum measured volumetric water content), approximate runoff volume, and approximate runoff volume in the first half hour were analysed to determine their effect on runoff capture and lag. During the monitoring period, 38% of observations did not produce measurable outflow. Logistic regression determined that the initial moisture deficit and approximate runoff volume were statistically significant in contributing to a fully captured storm. Despite the large hydraulic loading rate and concrete bottom, the planters demonstrate effective discharge lag, ranging from 5 to 1,841 min with a median of 77.5 min. Volumetric water content of the media and inlet runoff volume in the first half hour were significant in modelling the lag duration. These results represent a combination of controllable and uncontrollable aspects of green infrastructure: media design and rainfall.     

Developing an integrated urban ecological efficiency framework for spatial ecological planning: A case on a tropical mega metropolitan area of the global south

Rapid urbanization has emerged as one of the most critical challenges to ecological sustainability in urban areas. In developing countries, the degradation of the ecosystem is more prominent due to the lack of urban planning. Thus, it has become urgent for researchers to identify the ecological efficiency (EE) changes imposed by urban expansion and promote sustainable land use planning. This study aims to develop a comprehensive urban ecological efficiency (UEE) framework in the Kolkata Metropolitan Area (KMA), India, from 2000 to 2020. Principal component analysis (PCA) was used to develop a remote sensing-based UEE index (UEEI) based on five effective ecological parameters (Greenness, Dryness, Heat, Wetness and vegetation health. A single sensitivity parameter was also calculated to determine the role of a single parameter based on which management strategies can be carried out. The findings showed that (i) there were substantial deteriorations of UEE in the last 20 years. In 2000 the areas with good EE were about 65.5% which declined to 53.72% in 2010 and 20.87% in 2020. The areas with good UEE decreased 68% and 61% from 2000 to 2020 and 2010 to 2020, respectively; (ii) the areas with good UEE were 52% in 2000, while 38% in 2010. Most urban centres (Bhadreshwar, Champdani, Srirampur, Bally, Howrah, Kamarhati, Baranagar, Dum Dum, South Dum Dum, Rajarhat, Bidhannagar) located around the Kolkata megacity are characterized by poor and very poor EE (ranges of 0.60–1.00). Thus, spatiotemporal pattern of UEE could assist to clarify the administrative responsibilities as well as obligations. In addition to this, the UEE framework can help for scientific guidance of urban ecosystem protection and restoration through comprehensive spatial landscape planning.     

Comparison Of Upwind Land Use And Roughness Length Measured In The Urban Boundary Layer

The results of wind measurements taken in two studies at an urban sitein Birmingham (UK) are presented. Displacement heights and roughnesslengths are calculated that compare well with previous measurements inthe urban canopy. Dimensionless windshear and vertical-velocity standarddeviation are also shown to obey Monin–Obukhov similarity theory. Themean roughness lengths measured at the highest measuring position (45 m)increase with the fraction of upwind urban cover calculated using asource-area model.     

A Model to Calculate what a Remote Sensor `Sees' of an Urban Surface

Whilst the measurement of radiation emissions from a surface is relativelystraightforward, correct interpretation and proper utilization of the informationrequires that the surface area `seen' be known accurately. This becomes non-trivialwhen the target is an urban surface, due to its complex three-dimensional form andthe different thermal, radiative and moisture properties of its myriad surface facets.The geometric structure creates shade patterns in combination with the solar beamand obscures portions of the surface from the sensor, depending on where it is pointing and its field-of-view (FOV). A model to calculate these surface-sensor-sun relations (SUM) is described. SUM is tested against field and scale model observations, and theoretical calculations, and found to perform well. It can predict the surface area`seen' by a sensor of known FOV pointing in any direction when placed at any pointin space above a specified urban surface structure. Moreover, SUM can predict theview factors of the roof, wall and ground facets `seen' and whether they are sunlit orshaded at any location and time of day. SUM can be used to determine the optimalplacement and orientation of remote sensors to study urban radiation emissions; ifthe facet temperatures are known or modelled it can calculate the average temperatureof the system, and it can determine the directional variation of temperature (anisotropy) due to any particular surface-sensor-sun geometric combination. Thepresent surface geometry used in SUM is relatively simple, but there is scope to makeit increasingly realistic.     

Mapping narratives of urban resilience in the global south

In the context of global environmental change much hope is placed in the ability of resilience thinking to help address environment-related risks. Numerous initiatives aim at incorporating resilience into urban planning practices. The purpose of this paper is to open up a conversation on urban resilience by unpacking how diverse science methods contribute to the production of different narratives of urban resilience mobilizing different experts and forms of evidence. A number of scholars have cautioned against uncritical approaches to resilience and asked what resilience means and for whom, also pointing out the normative dimension of the concept. Building on this emerging scholarship we use insights from science and technology studies (STS) and critical social sciences to look at the knowledge infrastructures and networks of actors involved in the development of resilience strategies. Drawing on fieldwork in Manila, Nairobi, and Cape Town, we map different narratives of urban resilience identifying the ways in which science serves to legitimate or alienate particular perspectives on what should be done. We discuss the multiple roles that science methods have for resilience planning. Whereas urban resilience is often portrayed as consensual, we show that a range of narratives, with diverse socio-material implications, exist at the city level. In this way we unearth the conflict that lies beneath an apparent consensus for resilience policy and outline future research directions for urban sustainability.     

城市下垫面对河谷城市兰州冬季热岛效应及边界层结构的影响

利用中尺度数值模式WRF耦合单层城市冠层模块UCM,引入2005年MODIS土地利用类型资料,在对2005年1月25—28日兰州市热岛现象进行高分辨率数值模拟的基础上,设计了去除城市下垫面敏感性试验,探讨了城市下垫面对城市边界层的影响程度。结果表明,城市下垫面能使近地层大气温度升高而风速减小,并且,在夜间表现更明显。由城市热岛强度日变化分析可知,城市下垫面对兰州市热岛强度的贡献率为44%。夜间,城市上空200 m以下的近地层大气保持了白天的混合层特征,热岛环流的上升运动促进了山风环流,使得上升气流到达地面以上600 m左右;白天,由于山峰加热效应,城市上空400—600 m存在一个脱地逆温层,城市热岛环流使得11—15时（北京时）市区近地层出现弱上升气流,抑制了谷风环流的形成及发展。城市下垫面的低反照率特性和建筑物的多次反射作用导致城市下垫面的净辐射通量大于非城市下垫面;城市下垫面由于建筑材料的不透水性,导致潜热通量远小于感热通量,而储热项所占比重明显增大。     

Forty-three years of Ramsar and urban wetlands

The Ramsar Convention is unquestionably the backbone of modern wetland management theory and practice. In the last four decades, it has mainstreamed wetlands in the environmental discourse and fostered the development of a comprehensive institutional framework for wetland governance. However, many of the wetlands that occur in human-dominated landscapes remain acutely threatened. The problem is most alarming in urban areas, especially in the fast expanding cities of the developing world, where unprecedented wetland destruction is leading to recurring environmental disasters. This triggers the question: are these failures in wetland governance purely induced by factors exogenous to Ramsar-based institutions or are they manifestations of conceptual drawbacks within Ramsar conceptual framework. Here, we investigate the success and failures of the application of the Ramsar framework's policy directives and management guidelines for urban wetlands using two rapidly expanding cities in South Asia as case studies – Colombo (Sri Lanka) and Kolkata (India). We conclude that despite its remarkable achievements over the past four decades, the Ramsar framework has several conceptual drawbacks that weaken its effectiveness in complex urban contexts. An inadequate recognition of the complex dynamics of urban social-ecological systems, an inadequate recognition of the political complexity of the policy processes, and a lack of an environmental justice perspective are the main shortcomings contributing to failures in urban wetlands governance. While we acknowledge that some solutions are contingent upon national and transnational level socio-political processes and reforms, we offer a set of technical and strategic modifications to the Ramsar framework that can significantly improve its effectiveness in urban wetlands governance.