Urban Marsh Research Articles

Evaluating ecosystem services in urban salt marshes: Assessing vulnerability to sea-level rise and implications for coastal management

This study presents a spatio-temporal framework that integrates ecosystem services into ecological risk assessment to evaluate the ecosystem service vulnerability of urban salt marshes to sea-level rise. The model was tested at Belle Isle Marsh to quantify and qualify the evolving capacity of urban marshes to continue supplying ecosystem services to an increasing urban populace to the end of the century with focus on carbon storage, nitrogen storage, fish nursery, and Saltmarsh Sparrow viewing. We project that sea-level rise will drive dynamic trade-offs between habitats and ecosystem services over space and time. Ultimately, habitat fragmentation and coversion to open ocean will severely impair carbon storage and wildlife viewing services, while also enhancing short-term fish nursery and nitrogen storage services. This approach offers nuanced understanding of where, when, and how services may interact under future conditions, and enables proactive planning and adaptation to emerging challenges.

Suboptimal conditions lead to differences in habitat use and nest survival of imperiled tidal marsh sparrows between an urban marsh and nearby non-urban island

Suboptimal conditions lead to differences in habitat use and nest survival of imperiled tidal marsh sparrows between an urban marsh and nearby non-urban island

Cytogenotoxicity Screening of Urban and Rural Marshes: An Integrated In Vivo Approach Coupling Fish and Plant-Based Tests Adapted for Low-Income Countries.

Effects of anthropogenic activities such as urbanization, population growth, and agriculture on water quality are major concerns particularly in low-income countries where water quality monitoring can be challenging. The purpose of the present study was to evaluate the cytogenotoxic potential of water from urban and rural Malagasy marshes, coupling a fish (Nile tilapia, Oreochromis niloticus) and a plant (Allium cepa) species as bioindicators. The fish and plants were exposed for 72 h to water sampled in the two locations investigated. Using the comet assay on fish erythrocytes, DNA strand breaks were assessed, while mitotic index and nucleolar alterations were estimated in cells of the plant root apex. Comet assays revealed significant DNA strand breaks to fish erythrocytes in both the marshes investigated while the mitotic index and nucleolar characteristics in the roots of A. cepa mainly highlighted potential cytotoxicity in the urban marsh. Our results demonstrate the advantages of coupling in vivo biological test systems to screen potential cytogenotoxicity of surface water in low-income countries where comprehensive data sets of aquatic contaminants are often lacking. Environ Toxicol Chem 2023;42:1266-1275. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Close to the Madding Crowd: Waterbird Responses to Land Use Conversion in and Around a Mediterranean Urban Wetland

Investigating how Mediterranean wetlands respond to adjacent land use conversion, is an important first step in mitigating the impact of human encroachment and other environmental stressors. We monitored the composition and structure of waterbird assemblages, in a Mediterranean urban marsh, subjected to severe anthropogenic pressures. Remote sensing indicated that in the last two decades Boussedra Pond was subjected to landfill, resulting in a substantial reduction (~ 50 %) of the marsh, while due to a lack of urban planning urban built-up and agriculture areas expanded considerably in its surroundings. This precipitous reduction of the size of this urban pond threatens the diversity of its resident waterbirds which include the globally Endangered (EN) White-headed Duck Oxyura leucocephala, the Near-Threatened (NT) Ferruginous Duck Aythya nyroca, and many other staging and wintering migratory species. The long-term study suggested that breeding waterbirds species responded differentially to the loss and degradation of the marsh, as highlighted by the apparent resilience of the synanthropic Moorhen Gallinula chloropus and the disappearance of several breeding marsh specialists, such as the Little Bittern Ixobrychus minutus and the Western Marsh Harrier Circus aeruginosus. The study also points out the need for both a coordinated cross-sectorial land use planning and an immediate, affordable and sustainable wetland conservation action.

Spatial and Temporal Patterns of Chloride Contamination in a Shallow, Urban Marsh

High chloride concentrations occur in inland waters from road salt applications (NaCl) as deicers. We studied seasonal and spatial distributions of chloride contamination in a shallow, urban marsh in Madison, Wisconsin, during the warm-wet winter of 2012–13, the cold-dry winter of 2014–15, and in the ice-free season of 2015. Chloride concentrations at the open water sites ranged from 10 to 1,261 mg L−1. Marsh inflows include a storm sewer, direct precipitation, and distributed surface flow and inferred groundwater flow around the marsh’s perimeter. The upstream storm sewer had more influence on chloride concentrations in the upper marsh, whereas runoff from a large snow storage pile had more influence in the lower marsh. In the cold-dry winter, the storm sewer and ion exclusion from ice formation greatly influenced chloride concentrations. In the warm-wet winter, snow melt, and rain on snow events diluted chloride concentrations in the open marsh, while more snow and deicer use increased the role of a snow storage pile as a source of chloride. In the open-water sites in 2015, chloride concentrations decreased following rain, but continued to increase in drier periods, which suggests distributed overland and groundwater inflows provide a source of legacy chlorides to the marsh.

The role of macroinvertebrates in the distribution of lead (Pb) within an urban marsh ecosystem

Environmental risk from contaminated aquatic sediments requires an understanding of its spatial distribution, bioavailability and rate of transfer to resident aquatic and terrestrial biota. We hypothesized that macroinvertebrates play a role in the sequestration, distribution, and dispersal of lead from lead shot contaminated sediments. To assess this, we sampled the predominant aquatic macroinvertebrate, Leptocerus americanus, from sites within the La Crosse River Marsh (La Crosse, Wi) identified to contain high levels of lead contamination. We measured lead content in larval cases, larval tissues and emergent adult tissues. Lead concentrations within whole larvae correlated with levels of lead within sediments, and lead was differentially partitioned between larval tissue and their silk cases. Over 90% of the lead was retained in larval cases, while the rest was distributed to the body tissue, which was largely conserved during the process of metamorphosis. Our models support that L. americanus emerging from the marsh in the contaminated area transfer as much as 160 mgPb out of the aquatic habitat each year. Our work demonstrates that macroinvertebrates affect the mobilization and dispersal of contaminants within aquatic sediments, and this role should be evaluated when making management decisions regarding contaminated ecosystems.

Urban Land use Affects Resident Fish Communities and Associated Salt Marsh Habitat in Alabama and West Florida, USA

Urban land-use has been shown to impact aquatic environments however not much is known about the effects of low to medium density residential development. Fish and associated habitat were sampled along 23 salt marshes (dominated by Juncus roemerianus) across three urban and three reference tidal creeks of Alabama and west-Florida. Reference creeks had very little surrounding development while urban creeks were surrounded by residential neighborhoods typical for the region. Fish were sampled seasonally for one year along the marsh-water edge using baited minnow traps. Tidal creeks and marsh edges were also surveyed for various environmental attributes including: marsh species composition, stem density and biomass, sediment contaminants, marsh slope, salinity, and water temperature. Urban creeks showed evidence of longer freshwater conditions and greater salinity fluctuation. Total fish abundance and biomass were significantly lower in urban marshes (10.1 ± 1.3 fish trap−1 and 34.8 ± 5.1 g trap−1) compared to reference marshes (14.3 ± 1.8 fish trap−1 and 77.4 ± 10.0 g trap−1). Based on nonmetric multidimensional scaling (NMDS), urban and reference fish assemblages were clearly clustered and correlated with salinity, marsh slope and sediment Cd concentration. These results suggest that marshes in urban-residential tidal creeks may support modified habitats compared to undeveloped creeks.

Environmental Review and Case Studies: Is Urban Marsh Sustainability Compatible with the Clean Water Act?

The United States (US) Army Corps of Engineers and US Environmental Protection Agency share responsibility for regulating placement of fill material in coastal wetlands and open waters. However, ac...

Characterization of dissolved organic matter from a restored urban marsh and its role in the mobilization of trace metals

Dissolved organic matter (DOM), although highly variable and not very well characterized, plays a role in many important environmental reaction and transport processes, including trace metal mobilization. This study characterizes heterogeneous DOM from the pore-water of a restored urban tidal marsh, using chemical, optical, and electrochemical methods for dissolved organic carbon/nitrogen ratios (C:N: 1.8–6.4), spectroscopic characteristics (decreased aromaticity in amended sediments), element ratios (maximum sediment-associated trace metal concentrations measured<30cm), and metal complexation properties (logKc: Cd: 10.7±0.7>Pb: 9.5±0.1>Cr: 7.3±0.1>Cu: 5.07±0.53), all as a function of sediment depth.Specific DOM properties from the restored marsh were then compared to pore-water samples from a natural marsh and a simulated wetland microcosm which resulted in similar values, while the reference humic acid significantly differed in properties from field DOM. The results revealed that reference humic acids do not accurately represent the complexity of natural heterogeneous DOM, whereas a simulated wetland microcosm may provide a reasonable representation of natural DOM.Clear differences between amended and original soil (transition below 30cm) were observed in DOM and trace metal properties including: lower DOM content, higher logKc values, less DOM complexity, development of a iron-sulfide redox buffering pool, and greater affinity for metals in the solid phase occurring in the amended sediments.

Impacts of Adjacent Land Use and Isolation on Marsh Bird Communities

Over the next half century the human population is expected to grow rapidly, resulting in the conversion of rural areas into cities. Wetlands in these regions are therefore under threat, even though they have important ecosystem services and functions. Many obligate marsh-nesting birds in North America have shown declines over the past 40 years, and it is important to evaluate marsh bird community response to increased urbanization. We surveyed 20 coastal marshes in southern Ontario, Canada, and found that obligate marsh-nesting birds preferred rural over urban wetlands, generalist marsh-nesting birds showed no preference, while synanthropic species showed a trend towards increased richness and abundance in urban marshes. The Index of Marsh Bird Community Integrity (IMBCI) was calculated for each wetland and we found significantly higher scores in rural compared to urban wetlands. The presence of a forested buffer surrounding the marsh was not an important factor in predicting the distribution of generalists, obligates, synanthropic species, or the IMBCI. More isolated marshes had a lower species richness of obligate marsh-nesters and a lower IMBCI than less isolated marshes. Based on our results, we recommend that urban land use is not the dominant land use within 1000 m from any wetland, as it negatively affects the abundance and richness of obligate marsh-nesters, and the overall integrity of the avian community. We also recommend that all existing wetlands be conserved to mitigate against isolation effects and to preserve biodiversity.

Release of Metals by the Leaves of the Salt Marsh Grasses Spartina alterniflora and Phragmites australis

The perennial grass Spartina alterniflora, common to salt marshes of eastern North America, is known to accumulate metals from marsh sediment and release them into the environment. One pathway by which Spartina alterniflora releases metals is through the excretion of metal-containing salts produced by leaf salt glands. We examined the differential release of metals by Spartina alterniflora and the invasive perennial grass Phragmites australis in an urban marsh ecosystem. Leaching rates were measured by cleaning residues off leaf surfaces under field and controlled laboratory conditions. Leaf residues and leaf tissue were analysed for copper, chromium, lead and zinc by atomic absorption spectrophotometry.Spartina alterniflora was found to release significantly more metal through leaf tissue than Phragmites australis, under both field and laboratory situations. Spartina alterniflora was also found to accumulate significantly more chromium and lead in leaves than Phragmites australis. Therefore, Spartina alterniflora can release larger quantities of metals into the marsh environment than Phragmites australis, through both excretion and leaf deposition.