Uranium in natural wetlands: a hydrogeochemical approach to reveal immobilization processes

Some histories of California describe nineteenth-century efforts to reclaim the extensive swamplands and shallow lakes in the southern part of California's San Joaquin Valley – then the largest natural wetlands habitat west of the Mississippi River – as a herculean venture to tame a boggy wilderness and turn the region into an agricultural paradise. Yet an 1850s proposition for draining those marshes and lakes primarily was a scheme to improve the state's transportation. Swampland reclamation was a secondary goal. Transport around the time of statehood in 1850 was severely lacking in California. Only a handful of steamboats plied a few of the state's larger rivers, and compared to the eastern United States, roads and railroads were nearly non-existent. Few of these modes of transportation reached into the isolated San Joaquin Valley. As a result, in 1857 the California legislature granted an exclusive franchise to the Tulare Canal and Land Company (sometimes known as the Montgomery franchise, after two of the firm's founders). The company's purpose was to connect navigable canals from the southern San Joaquin Valley to the San Joaquin River, which entered from the Sierra Nevada about half way up the valley. That stream, in turn, joined with San Francisco Bay, and thus the canals would open the entire San Joaquin Valley to world-wide commerce. In exchange for building the canals, the Montgomery franchise could collect tolls for twenty years and sell half the drained swamplands (the other half was to be sold by the state). Land sales were contingent upon the Montgomery franchise reclaiming the marshes. Wetlands in the mid-nineteenth century were not viewed as they are today as fragile wildlife habitats but instead as impediments to advancing American ideals and homesteads across the continent. Moreover, marshy areas were seen as major health menaces, with the prevailing view being that swampy regions’ air carried infectious diseases.

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Wetland Restoration with Hydrophytes: A Review

Plants ◽

10.3390/plants10061035 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1035

Author(s):

Maria A. Rodrigo

Keyword(s):

Wetland Restoration ◽

Large Scale ◽

Emergent Plants ◽

Filamentous Green Algae ◽

Vital Functions ◽

Climatic Scenarios ◽

Restoration Practices ◽

Natural Wetlands ◽

Sediment Transfer ◽

Negative Factors

Restoration cases with hydrophytes (those which develop all their vital functions inside the water or very close to the water surface, e.g., flowering) are less abundant compared to those using emergent plants. Here, I synthesize the latest knowledge in wetland restoration based on revegetation with hydrophytes and stress common challenges and potential solutions. The review mainly focusses on natural wetlands but also includes information about naturalized constructed wetlands, which nowadays are being used not only to improve water quality but also to increase biodiversity. Available publications, peer-reviewed and any public domain, from the last 20 years, were reviewed. Several countries developed pilot case-studies and field-scale projects with more or less success, the large-scale ones being less frequent. Using floating species is less generalized than submerged species. Sediment transfer is more adequate for temporary wetlands. Hydrophyte revegetation as a restoration tool could be improved by selecting suitable wetlands, increasing focus on species biology and ecology, choosing the suitable propagation and revegetation techniques (seeding, planting). The clear negative factors which prevent the revegetation success (herbivory, microalgae, filamentous green algae, water and sediment composition) have to be considered. Policy-making and wetland restoration practices must more effectively integrate the information already known, particularly under future climatic scenarios.

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Effects of Grazer Exclusion on Carbon Cycling in Created Freshwater Wetlands

Land ◽

10.3390/land10080805 ◽

2021 ◽

Vol 10 (8) ◽

pp. 805

Author(s):

Delanie M. Spangler ◽

Anna Christina Tyler ◽

Carmody K. McCalley

Keyword(s):

Soil Carbon ◽

Carbon Cycling ◽

Belowground Biomass ◽

Freshwater Wetlands ◽

Wetland Creation ◽

Free Access ◽

Exclusion Experiment ◽

Herbivore Exclusion ◽

Sequestration Potential ◽

Natural Wetlands

Wetland ecosystems play a significant role in the global carbon cycle, and yet are increasingly threatened by human development and climate change. The continued loss of intact freshwater wetlands heightens the need for effective wetland creation and restoration. However, wetland structure and function are controlled by interacting abiotic and biotic factors, complicating efforts to replace ecosystem services associated with natural wetlands and making ecologically-driven management imperative. Increasing waterfowl populations pose a threat to the development and persistence of created wetlands, largely through intensive grazing that can shift vegetation community structure or limit desired plant establishment. This study capitalized on a long-term herbivore exclusion experiment to evaluate how herbivore management impacts carbon cycling and storage in a created wetland in Western New York, USA. Vegetation, above- and belowground biomass, soil carbon, carbon gas fluxes and decomposition rates were evaluated in control plots with free access by large grazers and in plots where grazers had been excluded for four years. Waterfowl were the dominant herbivore at the site. Grazing reduced peak growing season aboveground biomass by over 55%, and during the summer, gross primary productivity doubled in grazer exclusion plots. The shift in plant productivity led to a 34% increase in soil carbon after exclusion of grazers for five growing seasons, but no change in belowground biomass. Our results suggest that grazers may inhibit the development of soil carbon pools during the first decade following wetland creation, reducing the carbon sequestration potential and precluding functional equivalence with natural wetlands.

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Analysis of Characteristics and Driving Factors of Wetland Landscape Pattern Change in Henan Province from 1980 to 2015

Land ◽

10.3390/land10060564 ◽

2021 ◽

Vol 10 (6) ◽

pp. 564

Author(s):

Heying Li ◽

Jiayao Wang ◽

Jianchen Zhang ◽

Fen Qin ◽

Jiyuan Hu ◽

...

Keyword(s):

Correlation Analysis ◽

Constructed Wetlands ◽

Redundancy Analysis ◽

Yellow River ◽

Land Development ◽

Henan Province ◽

Driving Factors ◽

Wetland Area ◽

Natural Wetlands ◽

Temporal And Spatial

The study of the temporal and spatial evolution of wetland landscapes and its driving factors is an important reference for wetland ecological restoration and protection. This article utilized seven periods of land use data in Henan Province from 1980 to 2015 to extract the spatial distribution characteristics of wetlands and analyze the temporal and spatial changes of wetlands in Henan Province. Transfer matrix, landscape metrics, correlation analysis, and redundancy analysis were applied to calculate and analyze the transformation types and area of wetland resources between all consecutive periods, and then the main driving factors of wetland expansion/contraction were explored. First, the total wetland area in Henan Province increased by 28% from 1980 to 2015, and the increased wetland area was mainly constructed wetlands, including paddy field, reservoir and pond, and canal. Natural wetlands such as marsh, lake, and floodplain decreased by 74%. Marsh area declined the most during 1990–1995, and was mainly transformed into floodplain and “Others” because of agricultural reclamation, low precipitation, and low Yellow River runoff. The floodplain area dropped the most from 2005 to 2010, mainly converted to canals and “Others” because of reclamation, exploitation of groundwater, the construction of the South–to–North Water Transfer Project, and recreational land development. Second, the results of correlation analysis and redundancy analysis indicated that economic factors were positively correlated with the area of some constructed wetlands and negatively correlated with the area of some natural wetlands. Socioeconomic development was the main driving factors for changes in wetland types. The proportion of wetland habitat in Henan Province in 2015 was only 0.3%, which is low compared to the Chinese average of 2.7%. The government should pay more attention to the restoration of natural wetlands in Henan Province.

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Effects of Contemporary Land Use Types and Conversions from Wetland to Paddy Field or Dry Land on Soil Organic Carbon Fractions

Sustainability ◽

10.3390/su12052094 ◽

2020 ◽

Vol 12 (5) ◽

pp. 2094

Author(s):

Di Zhao ◽

Junyu Dong ◽

Shuping Ji ◽

Miansong Huang ◽

Quan Quan ◽

...

Keyword(s):

Land Use ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Constructed Wetland ◽

Paddy Field ◽

Heavy Fraction ◽

Light Fraction ◽

Paddy Fields ◽

Dry Land ◽

Natural Wetlands

Soil organic carbon (SOC) concentration is closely related to soil quality and climate change. The objectives of this study were to estimate the effects of contemporary land use on SOC concentrations at 0–20 cm depths, and to investigate the dynamics of SOC in paddy-field soil and dry-land soil after their conversion from natural wetlands (20 and 30 years ago). We investigated the dissolved organic carbon (DOC), light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), and other soil properties (i.e., moisture content, bulk density, pH, clay, sand, silt, available phosphorous, light fraction nitrogen, and heavy fraction nitrogen) in natural wetlands, constructed wetlands, fishponds, paddy fields, and soybean fields. The results indicated that the content of DOC increased 17% in constructed wetland and decreased 39% in fishponds, and the content of HFOC in constructed wetland and fishponds increased 50% and 8%, respectively, compared with that in natural wetlands at 0–20 cm. After the conversion of a wetland, the content of HFOC increased 72% in the paddy fields and decreased 62% in the dry land, while the content of DOC and LFOC decreased in both types. In the paddy fields, LFOC and HFOC content in the topmost 0.2 m of the soil layer was significantly higher compared to the layer below (from 0.2 to 0.6 m), and there were no significant differences observed in the dry land. The findings suggest that the paddy fields can sequester organic carbon through the accumulation of HFOC. However, the HFOC content decreased 22% after 10 years of cultivation with the decrease of clay content, indicating that paddy fields need to favor clay accumulation for the purpose of enhancing carbon sequestration in the paddy fields.

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Relationships between gregarine infection in damselflies, wetland type, and landscape characteristics

The Canadian Entomologist ◽

10.4039/n11-028 ◽

2011 ◽

Vol 143 (5) ◽

pp. 460-469 ◽

Cited By ~ 7

Author(s):

Julia J. Mlynarek ◽

Daniel G. Bert ◽

G. Haydeé Peralta-Vázquez ◽

Joanna A. James ◽

Mark R. Forbes

Keyword(s):

Forest Cover ◽

Road Density ◽

Natural Habitats ◽

Artificial Wetlands ◽

Wetland Type ◽

Landscape Characteristics ◽

Natural Wetlands ◽

Ischnura Verticalis ◽

Host Parasite ◽

Wetland Cover

AbstractAlthough human-modified landscapes are characterized by the loss of natural habitats, new habitats also can be created and exploited by many species. The importance of landscape change to invertebrate associations (particularly host-parasite associations) is understudied. Our objective was to determine whether prevalence and intensity of gregarine parasitism in the damselfly Ischnura verticalis (Say) (Odonata: Coenagrionidae) differed between 17 artificial and 7 natural wetlands in landscapes that varied in amount of forest and wetland cover and road density determined at spatial extents of 500m and 1km from each wetland. Wetlands were located in and around Ottawa, Ontario, and Gatineau, Quebec, Canada. Wetland type did not account for significant variation in principal components based on forest and wetland cover and road density at either spatial extent. Gregarine prevalence was higher in damselflies collected from natural wetlands than in those collected from artificial wetlands and was positively associated with increasing forest cover. In contrast, gregarine intensity was inversely related to road density. Our results suggest that parasitism of damselflies by gregarines is associated with wetland type and landscape characteristics, although the mechanisms producing such relationships are unknown.

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How important are aquatic predators to mosquito larval populations in natural wetlands? A case study from Carolina bays in Georgia

Wetlands Ecology and Management ◽

10.1007/s11273-017-9581-8 ◽

2017 ◽

Vol 26 (3) ◽

pp. 391-397 ◽

Cited By ~ 2

Author(s):

Darold P. Batzer ◽

Kelly M. Murray

Keyword(s):

Carolina Bays ◽

Natural Wetlands ◽

Aquatic Predators

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Farm Ponds as Potential Complementary Habitats to Natural Wetlands in a Mediterranean Region

Wetlands ◽

10.1007/s13157-011-0265-5 ◽

2012 ◽

Vol 32 (1) ◽

pp. 161-174 ◽

Cited By ~ 18

Author(s):

J. Jesús Casas ◽

Julia Toja ◽

Patricio Peñalver ◽

Melchor Juan ◽

David León ◽

...

Keyword(s):

Mediterranean Region ◽

Farm Ponds ◽

Natural Wetlands

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Landscape Characteristics and Ecological Risk Assessment Based on Multi-Scenario Simulations: A Case Study of Yancheng Coastal Wetland, China

Sustainability ◽

10.3390/su13010149 ◽

2020 ◽

Vol 13 (1) ◽

pp. 149

Author(s):

Peng Tian ◽

Luodan Cao ◽

Jialin Li ◽

Ruiliang Pu ◽

Hongbo Gong ◽

...

Keyword(s):

Risk Assessment ◽

Markov Model ◽

Ecological Risk ◽

Ecological Risk Assessment ◽

Coastal Wetland ◽

Landscape Planning ◽

Test Accuracy ◽

Artificial Wetlands ◽

Wetland Landscape ◽

Natural Wetlands

Carrying out coastal wetland landscape simulations and current and future ecological risk assessments is conducive to formulating policies for coastal wetland landscape planning and promoting the coordinated development of the social economy and ecological environment. This study used the Cellular Automaton (CA)-Markov model to simulate the landscape data of the study area under different scenarios in 2021 and 2025, and built an ecological risk assessment (ERS) index model to analyze the differences of spatio-temporal characteristics of ecological risks. The results showed that: (1) The test accuracy of the CA–Markov model was 0.9562 after passing through the consistency test. The spatial distribution data of landscapes under current utilization scenarios (CUSs), natural development scenarios (NDSs), and ecological protection scenarios (EPSs) were gained through simulations. (2) During 1991–2025, the landscape types of Yancheng coastal wetlands undertake complicated transfers and have vast transfer regions. Under CUSs and NDSs, a large number of natural wetlands are transferred to artificial wetlands. Under EPSs, the area of artificial wetlands declines and artificial wetlands are mainly transferred to natural wetlands. (3) The ecological risk of Yancheng Coastal Wetland increases, accompanied with significant spatial heterogeneity, which is manifested as low in the north area and high in the south area, and there exist some differences between sea areas and land areas. Ecological risk levels transfer violently.

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Mimosa pigra (giant sensitive plant).

10.1079/cpc.34199.20210099917 ◽

2021 ◽

Author(s):

Julissa Rojas-Sandoval ◽

Pedro Acevedo-Rodríguez

Keyword(s):

Rice Fields ◽

Invasive Weeds ◽

Tropical Africa ◽

Old World ◽

Mimosa Pigra ◽

Agricultural Weed ◽

Natural Wetlands ◽

The Cost ◽

Old World Tropics

Abstract M. pigra is a small prickly shrub that infests wetlands and is also an agricultural weed in rice fields in many parts of the old world tropics. In natural wetlands the shrub alters open grasslands into dense thorny thickets and negatively impacts on native biodiversity. It is regarded as one of the worst alien invasive weeds of wetlands of tropical Africa, Asia and Australia, and the cost of control is often high.

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