Wetland Loss Research Articles

Lessons learned from 30-years of operation of the Caernarvon Freshwater Diversion, Louisiana USA

Wetland loss is a worldwide issue with estimates of loss ranging from 50% to 71% in the 20th century. Louisiana's coastal zone lost approximately 4,830 km2, or 25% of the land area between 1932 and 2016 due to a variety of natural and anthropogenic forces that both erode and prevent the growth or maintenance of existing land. Freshwater diversions were constructed along the Mississippi River to convey freshwater, nutrients, and sediment from the Mississippi River to Louisiana's coastal basins to combat saltwater intrusion, nourish the marshes, and stimulate fisheries. The Caernarvon Freshwater Diversion (CFD) was authorized by the Flood Control Acts of 1928 and 1965, the 1974 Water Resources Development Act, and a 1984 Environmental Impact Statement, with construction completed and operations started in 1991. The CFD has been largely successful from the standpoint of the project's authorized goals. Early on in the project, the CFD helped combat saltwater intrusion in a 2,730 km2 basin and re-established the gradient from fresh to salt marsh, by creating conditions favorable to fresh marsh species. Although not a specific project goal, the CFD also built more than 700 acres of new emergent wetland between 1991 and 2016. By critically assessing 30 years of CFD governance, operations, monitoring, and adaptive management, lessons learned are developed that provide valuable information for making the operations and governance of current and future diversions more effective, transparent, adaptive, and trusted by the basin communities. Louisiana's Coastal Master Plan pivots to the use of river diversions to focus on land building and large-scale ecosystem restoration by mimicking natural processes that originally built the Louisiana deltaic landscape, rather than the more common small-scale restoration that has occurred over the past decades. However, large-scale restoration projects, by their nature, impact a wide variety of stakeholders and tend to cross political boundaries. Lessons learned from the CDF highlight the need for flexibility in the long-term and specificity in the short term in governing the operations of a large-scale coastal project. Recommendations developed for modernizing project implementation into the future given changing estuaries and climate will help increase effective implementation of larger-capacity river sediment diversions and other ecosystem-scale projects. It is time for big and bold action to restore south Louisiana and other coastal environments worldwide, and critical to success is using results from numerous past studies, applying lessons learned from existing projects like the CFD, and projections of future conditions.

Aptness of Seedling Age of Important Avenue Woody Species of Uttar Pradesh, India

Trees are an important component of our ecosystem, as far as ecological services provided by them are concerned. Especially in urban ecology, their role becomes more significant where they mitigate negative impacts of urbanization like deforestation; loss of wetlands; acquirement of agricultural lands; loss of biodiversity due to habitat clearing; degradation and fragmentation of the landscapes, etc. Trees make urban areas more resilient to these adverse impacts. Avenue plantation is an important part of Urban Forestry. In Avenue plantation, mostly tall seedlings are used. But planting very tall seedlings may affect the secondary growth of the tree, whereas planting small seedlings may be grazed by the animals. It is very important that the planting stock must be able of high rates of survival and good field performance to justify the expense of reforestation efforts. Therefore the present study is focused on the suitable planting age of some important preferred tree species of the Uttar Pradesh Forest Department and their growth performance in field conditions. The selected tree species were Shisham (Dalbergia sissoo), Imli (Tamarindus indica) Kathal (Artocarpus heterophyllus), Jungle Jalebi (Pithecellobium dulce), Kat sagaun (Haplophragma adenophyllum) and Karanj (Pongamia pinnata). These are the major woody species presently being planted in urban forestry. The species with large crown are planted in government garden, city garden, etc. Different age groups of these tree species were planted and their growth performance was studied under different field conditions. Aptness and importance of seedling age were recommended for studied trees for avenue plantation. It was concluded that species like Jungle Jalebi (Pithecellobium dulce), Katsagaun (Haplophragma adenophyllum), and Shisham (Dalbergia sissoo ) seedlings performed well for one year old age as well as for two year old age ones but species like Karanj( Pongamia pinnata), Imli ( Tamarindus indica ) and Kathal (Artocarpus heterophyllus), performed well more for one year old seedling. Therefore all these may be planted after one year of age in nursery to avoid the extra expense of maintaining these seedlings in the nursery stage.

Plan Integration for Ecological Resilience: Examining Factors Associated with Wetland Alteration

A community’s resilience is strongly influenced by the growth management guidance provided by its network of plans. Wetland loss has been shown to amplify flood damage. This study explores the relationship between plan integration and wetland alteration, comparing the findings from Fort Lauderdale, Florida, and League City, Texas. Combining spatial analytics, a Plan Integration for Resilience Scorecard™ evaluation, and correlational statistics, we find that wetland loss is significantly associated with plan integration and development patterns and is less acute in League City than Fort Lauderdale. Integrating wetland protection policies throughout a network of plans helps build resilience to flood hazards.

Human activities dominate a staged degradation pattern of coastal tidal wetlands in Jiangsu province, China

The tidal wetlands in Jiangsu Province (JS) play a crucial role as a major blue carbon sink in the eastern coastal area of China. These wetlands also contribute significantly function to biodiversity and the provision of ecosystem services. However, due to the escalating impact of anthropogenic activities and climatic changes, the ecological scope, structure, and function of tidal wetlands have changed drastically. This study aims to depict the spatiotemporal dynamics of these wetlands and explore the driving forces behind these changes. Based on the Google Earth Engine (GEE) platform, we conducted a comprehensive analysis of all the available Landsat imagery (5096 images, 30-m spatial resolution) using the Continuous Change Detection and Classification (CCDC) algorithm. The outputs consist of annual land cover maps of JS coastal zone, from 1990 to 2020. Results indicate that the generated coastal maps generally exhibit an exceptionally high average accuracy (92.62%) and there were 2666.54 km2 of tidal wetlands (Spartina alterniflora: 240.86 km2, Suaeda salsa: 37.31 km2, Phragmites australis: 150.63 km2, intertidal flat: 2158.18 km2, supratidal barren flat: 79.53 km2) in 2020, amounting to a 23.43% decrease of the initial year 1990. The tidal wetlands landscape had a staged decline during 1990–2020, and the hydrological vegetation habitat was the area with the greatest variability. Over the past three decades, the losses of tidal wetlands amounted to 1,466.22 km2, partially offset by gains of 650.05 km2. The two most substantial sources of losses were intertidal flat and Suaeda salsa with the most significant ratio of loss to gain (4.80, 10.31, respectively). Generally, we categorized tidal wetlands degradation into three transformation processes: human activities, species invasion, and natural succession. Human activities, particularly the conversion of intertidal flat into aquafarm, dominated the entire degradation process. Meanwhile, in the main driving analysis, we discovered that 60% of these losses and gains were directly tied to human activities. The indirect driving process includes natural coastal movements, climate change, unobservable human activities, and their aggregate effects, which gradually assist tidal wetlands ecosystems to re-establish and recover. The annual coastal wetland maps and detailed information on the evolutionary patterns and the corresponding drivers are valuable for identifying blue carbon distribution and enhancing the ecological services of the coastal zone.

Understanding Drivers of Salinity and Temperature Dynamics in Barataria Estuary, Louisiana

AbstractBarataria Estuary is an economically and ecologically important estuary in coastal Louisiana, USA. Due to rapid wetland loss, extreme Mississippi River flood and drought events (e.g., the flood of 2019 and the drought of 2022), devastating storm events (e.g., Hurricane Ida in 2021), eustatic sea‐level rise (SLR), high subsidence rates, and human activities, temporal and spatial variability of salinity and temperature in the estuary is highly complex. This study comprehensively investigates environmental drivers that govern salinity and temperature dynamics, as well as the effects of a proposed large‐scale, land‐building diversion of Mississippi River water. A three‐dimensional (3D), process‐based hydrodynamic, salinity and temperature transport model system is formulated and implemented. Three different modeling domains are set up for nested computations. The model system is validated for the year 2018 against measurements of water level, salinity, and temperature. A series of numerical experiments are then carried out to quantitatively examine impacts of various environmental drivers, as well as nearshore density stratification and local baroclinic forcing. The drivers include wind, rainfall, freshwater point‐source diversion, SLR, and Mississippi River discharge. Interestingly, the analysis shows that the proposed Mid‐Barataria diversion and rainfall can cause a reduction of annual salinity up to 14 and 10 ppt, respectively. Neglecting the effect of nearshore density stratification could underestimate salinity by up to 9 ppt. The well‐mixed estuary can be adequately modeled using depth‐averaged models. However, to adequately capture proper salinity and temperature stratification, it is necessary to use 3D models for the coastal regional domain.

Will They Stay or Will They Go — Understanding South Atlantic Coastal Wetland Transformation in Response to Sea-Level Rise

Threats to coastal wetlands, including sea-level rise and subsidence, led the National Wildlife Refuge (NWR) System to protect over 500,000 hectares of coastal wetlands during the twentieth century, with approximately 20% occurring in the South Atlantic geography. This effort has involved systematic long-term monitoring of changes in marsh elevation using surface elevation tables and marker horizons at 20 sites across 19 NWRs in the southeastern coastal USA. From 2012 to 2021, the rates of change in surface elevation (−9.3 to 7.1 mm/year), accretion (−0.3 to 17.5 mm/year), and net vertical elevation change (−14.3 to 3.1 mm/year) were highly variable among monitoring sites and varied with coastal wetland type (oligohaline marsh, salt marsh, pocosin, or forested wetland), land surface elevation, and estuarine salinity and geomorphology (i.e., tidally influenced or embayed). Of 20 sites included in our study, only six were gaining elevation at a rate that was equal to or greater than the long-term rates of sea-level rise and therefore considered resilient. Only Waccamaw and Currituck NWRs, both located in oligohaline marshes, were gaining elevation at a rate that exceeded sea-level rise by 1 mm/year. These results support the mounting evidence that many coastal wetlands, particularly in the South Atlantic geography of the USA, will undergo ecological transformations in the next several decades. The NWR System and other coastal management entities will need to use strategic decision-making frameworks to identify management actions that can mitigate the loss of coastal wetlands to support the conservation of coastal wetland–dependent and obligate species.

Identifying driving hydrogeomorphic factors of coastal wetland downgrading using random forest classification models

Coastal wetlands provide critical ecosystem services but are experiencing disruptions caused by inundation and saltwater intrusion under intensified climate change, sea-level rise, and anthropogenic activities. Recent studies have shown that these disturbances downgraded coastal wetlands mainly through affecting their hydrological processes. However, research on what is the most critical driver for wetland downgrading and how it affects coastal wetlands is still in its infancy. This study examined drivers of three types of wetland downgrading, including woody wetland loss, emergent herbaceous wetland loss, and woody wetlands converting to emergent herbaceous wetlands. By using random forest classification models for the wetland ecosystems in the Alligator River National Wildlife Refuge, North Carolina, USA, during 1995–2019, we determined the relative importance of different hydrogeomorphic processes and the dominant variables in driving the wetland downgrading. Results showed that random forest classification models were accurate (> 97 % overall accuracy) in classifying wetland downgrading. Multiple hydrogeomorphic variables collectively contributed to the coastal wetland downgrading. However, the dominant control factors varied across different types of wetland downgrading. Woody wetlands were most susceptible to saltwater intrusion and were likely to downgrade if the saltwater table was shallower than 0.2 m below the land surface. In contrast, emergent herbaceous wetlands were most vulnerable to inundation and drought. The favorable groundwater table for emergent herbaceous wetlands was between 0.34 m above the land surface and 0.32 m below the land surface, beyond which the emergent herbaceous wetland tended to disappear. For downgraded woody wetlands, their distance to canals/ditches played a crucial role in determining their fates after downgrading. The machine learning approach employed in this study provided critical knowledge about the thresholds of hydrogeomorphic variables for the downgrading of different types of coastal wetlands. Such information can help guide effective and targeted coastal wetland conservation, management, and restoration measures.

Waterbird–habitat relationships in South Carolina: implications for protection, restoration, and management of coastal and inland wetlands

South Carolina coastal and inland wetlands are continentally important to resident, migrating, and wintering dabbling ducks (Anatini), diving and sea ducks (Aythini, Mergini, Oxyurini), pelagic waterbirds (Anhingidae, Laridae, Pelicanidae, and Phalcrocoracidae), and wading birds (Ardeidaie, Ciconiidae, Threskiornithidae). Our goal was to model wetland selection of these waterbird guilds in South Carolina during autumn–winter to determine habitat preferences and guide wetland conservation and restoration amid sea‐level rise and other coastal pressures. We conducted aerial surveys and recorded waterbird occurrence and relative abundance in winters 2017–2019. We modeled waterbird–habitat relationships relative to managed and unmanaged coastal and inland wetlands, legally protected conservation lands (e.g. federal, state, and private easements), and habitat diversity. Waterbirds selected a variety of wetlands emphasizing the importance of wetland diversity within habitat complexes. However, only managed tidal impoundments (MTIs) and protected conservation lands were selected across all waterbird guilds. Results suggest these are contemporary keystone habitats for promoting wintering waterbird abundance and diversity in South Carolina and other South Atlantic coastal regions. To compensate for future coastal wetland loss while facilitating the current and future needs of migrating and wintering waterbirds, we recommend: (1) identification and continued management of MTIs resilient to sea‐level rise; (2) strategic planning and partnerships for land acquisition and legal protections inland; and (3) land protection networks between extant coastal and inland sites designated for future construction and emigration of decommissioned MTIs. Stakeholder and partner engagement is paramount to prioritize resource allocation for the restoration, construction, and decommissioning of coastal and inland wetlands.

Influences of urban stormwater management ponds on wetlandscape connectivity

Wetlands have been degraded and destroyed in many human-dominated landscapes worldwide, threatening vital ecosystem services. Landscape connectivity is critical for wetland biota, but is often reduced among remaining wetlands. With urban development, stormwater management (SWM) ponds are installed to hold runoff and associated contaminants. Unfortunately, SWM ponds do not adequately replace the ecosystem services and functions provided by a connected wetlandscape. We use a graph theory approach to analyze landscape connectivity of wetlands and stormwater management ponds in seven municipalities in southern Ontario, Canada. We analyze changes in connectivity through time, alongside potential effects of SWM pond creation on connectivity. We calculate the number of links (NL) and components (NC) at the landscape-level (i.e. connectivity within a municipality), and the probability of connection and two of its components (i.e. dPCflux and dPCconnector) at the habitat-level (i.e. contributions of individual wetlands and SWM ponds to landscape connectivity). Our results suggest that landscape connectivity has decreased with wetland loss, while SWM pond construction has improved connectivity. Wetlands appear to be more connected over the landscape, while SWM ponds might act as stepping-stones for species moving between wetlands. Our results point towards the need to protect and restore wetlands to safeguard critical ecosystem services. Stormwater ponds may not provide habitat of equivalent quality to wetlands; however, their strategic placement within urban areas could improve wetlandscape connectivity.

Analysis of long-term spatio-temporal wetland change reveals the complex nature of habitat alterations – A case study from the Czech Republic 1842–2017

Wetlands fulfil a number of functions in the landscape, especially non-productive ones. Information on landscape and biotope changes is important not only from a theoretical point of view for understanding the forces and pressures that cause changes in the landscape, but also from a practical point of view, as we can take inspiration from history when planning the landscape. The main goal of this study is to analyse the dynamics and trajectories of changes in wetlands, including testing the influence of the main natural conditions (climate, geomorphology) on their changes, for a large area of 141 cadastral territories (1315 km2), which will allow the results to be sufficiently generalized. The results of our study confirmed the global trend of rapid wetland loss, with almost three quarters of wetlands disappearing, mostly on arable land (37 %). The results of the study are of great importance in the field of the ecology of landscapes and wetlands, both in the national and international context, not only because they make it possible to understand the regularities and forces that affect changes in wetlands and landscapes, but also have significance due to the methodology. The specific methodology and procedure are based on the application of advanced GIS functions (Union and Intersect functions) to identify the location and area of individual change dynamics and types of wetland (new, extinct, continuous), using accurate old large-scale maps and aerial photographs. The proposed and tested methodological procedure can generally be used for wetlands in other locations, but also for studying the dynamics of changes and trajectories of other biotopes in the landscape. The greatest potential for using the results of this work in the field of environmental protection is the possibility of using the places of extinct wetlands for their restoration.

Effects of Human Encroachment on Wetlands: A Case of Boreal Shield, Canada

Wetlands are some of the most productive ecosystems on the planet and provide a wide range of ecological, economic, and social benefits. Wetlands are threatened by human activities such as agriculture, urbanization, resource extraction, and infrastructure development, which can lead to their degradation and loss. Wetland loss can result in reduced water quality, increased erosion, and decreased biodiversity, which can impact the health of ecosystems and the species that depend on them. The study found that human encroachment on wetlands in Canada has resulted in significant wetland loss and degradation. Wetland loss and degradation can lead to the loss of plant and animal species that depend on these ecosystems. It was noted that wetland loss is a major contributor to the decline of many bird species, including waterfowl and shorebirds. Wetlands support important industries such as forestry, agriculture, and fisheries, and provide recreational opportunities for Canadians, such as fishing, hunting, and wildlife watching. The study concluded that human activities such as agriculture, urbanization, resource extraction, and infrastructure development have led to the degradation and loss of wetlands across the country. The loss of wetlands has had a significant impact on the environment. Wetlands act as natural water filters, helping to purify water by removing pollutants and sediments. The loss of wetlands has also had economic and social impacts. Wetlands provide a range of valuable resources, including timber, peat, fish, and wildlife, which support local economies and communities. The study recommended that the Canadian government should implement more stringent wetland protection policies and regulations. This could include increasing the amount of wetlands protected under legislation, improving enforcement measures, and establishing penalties for those who violate wetland protection regulations. Public education and outreach programs should be developed and implemented to raise awareness about the importance of wetlands and the negative impacts of human encroachment. Keywords: Human Encroachment, Wetlands, Canada

Wetland Loss in Coastal Louisiana Drives Significant Resident Population Declines

Despite increased hurricane intensity, the U.S. Gulf of Mexico coast has experienced dramatic coastal population increase of 24.5% from 2000 to 2016. However, in areas of coastal Louisiana with dramatic wetland loss, parishes have experienced population declines and lower rates of population growth. Therefore, understanding the magnitude of the effect of wetland loss as a main driver of population loss in coastal Louisiana is critical. Using regression analysis, this study finds that wetland loss has a significant and persistent negative effect on population growth in coastal Louisiana. This effect resulted in a reduction in the population growth rate in coastal parishes over time. A counterfactual simulation was conducted to estimate the potential population size in the absence of wetland loss from 1990 to 2021. On average, the effect of 1 hectare of wetland lost causes a reduction of approximately 1000 persons. This indicates that for the year 2021, the population was approximately 18% lower than the population that would have existed in the absence of wetland loss. This research underscores the role of wetlands in providing direct and indirect benefits to people in coastal Louisiana that are ultimately reflected in its population levels.

Impact of wetland change on ecosystem services in different urbanization stages: A case study in the Hang-Jia-Hu region, China

Urbanization has had a profound impact on wetlands, and wetland conservation and restoration have attracted much attention. However, the detailed impacts of different urbanization and wetland changing processes on ecosystem services (ESs) are not well understood. Based on long-time series of remote sensing data (1990–2020), flood mitigation (FM), water purification (WP), carbon sequestration (CS), and biodiversity conservation (BC) were quantified in the Hang-Jia-Hu (HJH) region, China. According to the changing trend of urban land, the study period was divided into three urbanization stages: slow urbanization (1990–1998), rapid urbanization (1998–2013), and moderate urbanization (2013–2020). Regression analysis was used to explore the quantitative relationship between urbanization/wetland changes and ESs. The results showed that the urban land expansion rates in the slow urbanization, rapid urbanization, and moderate urbanization stages were 46.51 km2/yr, 100.62 km2/yr, and 70.87 km2/yr, respectively, and the corresponding wetland changing rates were 5.14 km2/yr, 19.54 km2/yr and −20.88 km2/yr, respectively. FM decreased in the slow and moderate urbanization stages and increased in the rapid urbanization stage, and WP increased in the slow and rapid urbanization stages and decreased in the moderate urbanization stage. Urbanization led to a decrease in FM, CS, and BC. Wetland restoration improved these ESs, while wetland loss caused a decline in multiple ESs in the slow and rapid urbanization stages. Wetland restoration partially offsets the negative effects of urbanization and wetland loss on ESs in the rapid urbanization stage. Urbanization and wetland changes have linear and nonlinear effects on ESs in different urbanization stages. Wetland restoration is an effective way to improve ESs in urbanization regions. This study can make an important contribution to sustainable wetland ecosystem development in urbanization regions.

Influence of Increased Freshwater Inflow on Nitrogen and Phosphorus Budgets in a Dynamic Subtropical Estuary, Barataria Basin, Louisiana

Coastal Louisiana is currently experiencing high rates of wetland loss and large-scale ecosystem restoration is being implemented. One of the largest and most novel restoration projects is a controlled sediment diversion, proposed to rebuild and sustain wetlands by diverting sediment- and nutrient-rich water from the Mississippi River. However, the impact of this proposed sediment diversion on the nutrient budget of the receiving basin is largely unknown. A water quality model was developed to investigate the impact of the planned Mid-Barataria Sediment Diversion on the nutrient budget of the Barataria Basin (herein referred to as ‘the Basin’). The model results indicate that the planned diversion will increase TN and TP pools by about 38% and 17%, respectively, even with TN and TP loadings that increase by >300%. Water quality model results suggest that the increase of nutrients in the basin will be mitigated by increased advection transport (i.e., decreased residence time from ~170 days to ~40 days, leading to greater flushing) and increased removal via assimilation, denitrification, and settling within the Basin. Advection transport resulted in higher TN removal in the Basin than other processes, such as uptake or denitrification. Approximately 25% of the additional TN loading and 30% of the additional TP loading were processed within the Basin through the assimilation of phytoplankton and wetland vegetation, denitrification, and burial in the sediment/soils. These nutrient budgets help to better understand how the planned large-scale sediment diversion project may change the future ecological conditions within the estuaries of coastal Louisiana and near-shore northern Gulf of Mexico.

Tracking economic-driven coastal wetland change along the East China Sea

Coastal wetlands provide various ecological functions but are threatened by land reclamation and urbanization, which cause wetland degradation and loss. Understanding wetland transition trends and driving factors is challenging. Here, we used the Environmental Kuznets curve (EKC) to analyze the relationship between coastal wetlands, as classified by the Google Earth Engine (GEE), and socio-economic indicators along the East China Sea. Structural equation modeling (SEM) was used to explore the driving factors. We found that the (1) wetland transition depended on geomorphic units and socio-economic development; (2) wetland area changes from 1985 to 2020 had a typical EKC pattern and can be divided into three periods due to policy changes; and (3) economic development and urbanization were the primary reasons for wetland changes, with a strong correlation between natural wetland area, GDP per capita, and impervious surface, but a lower correlation with aquacultural area.

Spatiotemporal Patterns in Land Use/Land Cover Observed by Fusion of Multi-Source Fine-Resolution Data in West Africa

Land Use/Land Cover (LULC) change is a major global concern and a topic of scientific debate. In West Africa, the key trend among the changes of the past few years is the loss of natural vegetation related to changes in different LULC categories, e.g., water bodies, wetland, and bare soil. However, not all detected changes in these LULC categories are relevant for LULC change management intervention in a resource-constrained continent, as a massive change in the dominant LULC types may be due to errors in the LULC maps. Previous LULC change analysis detected large discrepancies in the existing LULC maps in Africa. Here, we applied an open and synergistic framework to update and improve the existing LULC maps for West Africa at five-year intervals from 1990 to 2020—updating them to a finer spatial resolution of 30 m. Next, we detected spatial–temporal patterns in past and present LULC changes with the intensity analysis framework, focusing on the following periods: 1990–2000, 2000–2010, and 2010–2020. A faster annual rate of overall transition was detected in 1990–2000 and 2010–2020 than in 2000–2010. We observed consistent increases in shrubland and grassland in all of the periods, which confirms the observed re-greening of rangeland in West Africa. By contrast, forestland areas experienced consistent decreases over the entire period, indicating deforestation and degradation. We observed a net loss for cropland in the drought period and net gains in the subsequent periods. The settlement category also gained actively in all periods. Net losses of wetland and bare land categories were also observed in all of the periods. We observed net gains in water bodies in the 1990–2000 period and net losses in the 2010–2020 period. We highlighted the active forestland losses as systematic and issued a clarion call for an intervention. The simultaneous active gross loss and gain intensity of cropland raises food security concerns and should act as an early warning sign to policy makers that the food security of marginal geographic locations is under threat, despite the massive expansion of cropland observed in this study area. Instead of focusing on the dynamics of all the LULC categories that may be irrelevant, the intensity analysis framework was vital in identifying the settlement category relevant for LULC change management intervention in West Africa, as well as a cost-effective LULC change management approach.

A canal, urban sprawl and wetland loss: The case of Kozhikode, India, from colonialism to climate change era

AbstractWetlands have historically been considered hindrances to development, with ‘reclamation’ considered the appropriate management practice. This is no different in India, where most cities are built on wetlands. This study examines the case of fast urbanising Kozhikode City on the south‐west coast of India by overlaying political and developmental interventions of the city with its ecological realities. While pre‐colonial settlements in the region were predominantly along the coast leaving the marshy inland areas, the need for resource mobilisation by colonial forces led to the development of Conolly Canal through the wetlands. The spoil bank of the canal spawned the development of roads cutting across the wetlands, a process continuing to this day, with consequent ribbon development. Wetland loss due to reduction in depth, core area loss, fragmentation and salinity intrusion have gone hand in hand with the city's rapid urbanisation. While the looming threat of climate change is forcing Kozhikode's planners to revive the canal, wetlands that sustain the canal (and the city) are buried too far beneath the piecemeal undertakings that have shaped the city. This paper reconstructs the environmental history of the city, the canal and the wetlands from the establishment of the city to the present, spanning a period of 500 years. Determinants of urban growth including canal construction, transport network development in line with the spoil banks and rapid urbanisation processes are chronicled to understand the interconnectedness between ecology, urban sprawl and the rationality of disaster preparedness. In this context, the future development proposals for the region are examined especially with the wetlands as the backdrop. We employ mixed methodologies to track this history including satellite imagery, geographic information systems (GIS), archives and interviews with senior citizens. This framework can be applied to other cities to understand the metabolic relationship of urban growth with ecology and its changing history.

Economic and socioecological perspectives of urban wetland loss and processes: a study from literatures.

Existing literatures across the world highlighted the causes and rate of wetland loss; however, so far, no researches tried to analyze how these are guided by the socioeconomic and ecological conditions. The current review work wished to explore how economic and socioecological perspectives could control the rate and drivers of urban wetland loss. Through meta-analysis, this study also intended to explore the changing polarity in research publication and collaborative research. Total 287 original research articles indicating the rates and drivers of wetland loss from 1990 to June 2022 for the first objective and 1500 articles focusing wetland researches from Dimensions AI database for the last objective were taken.Results clearly revealed that the rate of urban wetland loss varies from 0.03 to 3.13% annually, and three main drivers like built-up, agricultural expansions, pollution were identified all across the world. Loss rate was found maximum in the developing and least developed countries. Pollution, built-up expansion, and agriculture expansion, respectively, in developed, developing, and least developed nations were identified as the most dominant drivers of urban wetland loss. Linking loss rate and drivers with socioecological and economic perspectives revealed that human development index (HDI), ecological performance index (EPI), sustainable development goal index (SDGI), and social progress index (SPI) is negatively associated with the rate of urban wetland loss. Contrarily, a poverty rate encouraged higher rate of loss. This study articulated that improving these socioecological and economic conditions could help wetland conservation and restoration to achieve SDGs.

Reference genome of the black rail, Laterallus jamaicensis.

The black rail, Laterallus jamaicensis, is one of the most secretive and poorly understood birds in the Americas. Two of its five subspecies breed in North America: the Eastern black rail (L. j. jamaicensis), found primarily in the southern and mid-Atlantic states, and the California black rail (L. j. coturniculus), inhabiting California and Arizona, are recognized across the highly disjunct distribution. Population declines, due primarily to wetland loss and degradation, have resulted in conservation status listings for both subspecies. To help advance understanding of the phylogeography, biology, and ecology of this elusive species, we report the first reference genome assembly for the black rail, produced as part of the California Conservation Genomics Project (CCGP). We produced a de novo genome assembly using Pacific Biosciences HiFi long reads and Hi-C chromatin-proximity sequencing technology with an estimated sequencing error rate of 0.182%. The assembly consists of 964 scaffolds spanning 1.39 Gb, with a contig N50 of 7.4 Mb, scaffold N50 of 21.4 Mb, largest contig of 44.8 Mb, and largest scaffold of 101.2 Mb. The assembly has a high BUSCO completeness score of 96.8% and represents the first genome assembly available for the genus Laterallus. This genome assembly can help resolve questions about the complex evolutionary history of rails, assess black rail vagility and population connectivity, estimate effective population sizes, and evaluate the potential of rails for adaptive evolution in the face of growing threats from climate change, habitat loss and fragmentation, and disease.

Reference genome of the Virginia rail, Rallus limicola.

The Virginia rail, Rallus limicola, is a member of the family Rallidae, which also includes many other species of secretive and poorly studied wetland birds. It is recognized as a single species throughout its broad distribution in North America where it is exploited as a game bird, often with generous harvest limits, despite a lack of systematic population surveys and evidence of declines in many areas due to wetland loss and degradation. To help advance understanding of the phylogeography, biology, and ecology of this elusive species, we report the first reference genome assembly for the Virginia rail, produced as part of the California Conservation Genomics Project (CCGP). We produced a de novo genome assembly using Pacific Biosciences HiFi long reads and Hi-C chromatin-proximity sequencing technology with an estimated sequencing error rate of 0.191%. The assembly consists of 1,102 scaffolds spanning 1.39 Gb, with a contig N50 of 11.0 Mb, scaffold N50 of 25.3 Mb, largest contig of 45 Mb, and largest scaffold of 128.4 Mb. It has a high BUSCO completeness score of 96.9% and represents the first genome assembly available for the genus Rallus. This genome assembly will help resolve questions about the complex evolutionary history of rails and evaluate the potential of rails for adaptive evolution in the face of growing threats from climate change and habitat loss and fragmentation. It will also provide a valuable resource for rail conservation efforts by quantifying Virginia rail vagility, population connectivity, and effective population sizes.