Adjacent Wetlands Research Articles

Valley‐bottom wetlands as temporary buffers for source‐to‐sink dispersal of sediment and associated phosphorus in dryland landscapes

AbstractSediment trapping in wetlands is an essential ecosystem service, with implications for downstream ecosystems and water users. There is however limited empirical evidence of the contemporary rates and magnitude of sediment trapping in valley‐bottom wetlands. Time‐averaged suspended sediment samples from the inlets and outlets of forestry‐ and agriculturally‐impacted valley‐bottom wetlands with contrasting morphometric characteristics were compared in terms of suspended sediment and associated total phosphorous (total P) fluxes over annual scales, a dataset that was limited by Covid travel constraints. Although both wetlands were net depositional, contemporary suspended sediment mass balances for the agriculturally‐impacted wetland revealed a temporal change in the amount of sediment trapped over two water years (2019/2020 and 2020/2021), with trapping efficacies of 91% and 24%, respectively. The proportion of sediment trapped in the water year of 2020/2021 within the adjacent wetland, with a small commercially forested catchment, was up to 4 times higher than the agriculturally‐impacted wetland, which drained a larger catchment. Rates of total P retention showed that the agriculturally‐impacted wetland was a net sink for phosphorus in 2019/2020, but shifted to a source of phosphorus in 2020/2021 as the export of suspended sediment was enhanced. However, this contrasts with the forestry‐impacted wetland, which was a net sink of sediment and associated phosphorus during the one‐year study period of 2020/2021. Overall, despite data constraints, this study suggests that the efficacy of valley‐bottom wetlands in the delivery of sediment trapping and phosphorus removal ecosystem services varies temporally and spatially. This variability is potentially related to the interaction between annual rainfall regimes, catchment size and wetland geomorphic character. The temporary nature of sediment recycling processes could serve to balance wetland dynamics by regulating vertical growth of valley floors and longitudinal slope stability and should be considered in catchment management and wetland restoration planning strategies.

Impacts of sea-access roads on wetland landscape dynamics in the Yellow River Delta front

The coevolution between oilfield development and deltaic wetlands is critical for ensuring environmental sustainability in mega-deltas. In the Yellow River Delta (YRD), the construction of offshore artificial islands and their sea-access roads (SARs) in delta fronts, providing accommodation for oilfields development of oilfields influences the evolution of adjacent wetland landscapes. This study utilized the threshold segmentation method based on MNDWI and the object-oriented random forest algorithm to extract the shoreline and classify typical wetland vegetation in the study area. It also analysed the impact of SAR on the landscape dynamics of coastal wetlands from 2004 to 2020. The results show that the SAR significantly affected the local sediment transport and erosion and accretion patterns in its adjacent coast, which has gone through accretion-domination, erosion, and continuous accretion stages, with significant accretion and erosion on the north and south sides of the SAR, respectively. From 2004 to 2020, 13.74 km2 of new-born wetland was formed, and the vegetation dynamics in the study area transformed from primary succession to human-disturbed succession. Spartina alterniflora (S. alterniflora) grew rapidly from 4.15 km2 to 18.04 km2 during 2010–2016, showed an imbalanced distribution on both sides of the SAR. This research can provide references for the sustainable coevolution of offshore oilfields and coastal environments.

The expected impacts of sea level on the Mexican Atlantic coast

The Mexican Atlantic coast is vulnerable to sea level rise due to its low, sandy shorelines with extensive adjacent wetlands. The increasing trends at the regional level are similar to global trends (~3 ± 0.04 mm/year): between 1.8 mm/year in Alvarado, Veracruz, to 3.6 mm/year in Isla Mujeres, Quintana Roo. A synthetic model was applied to Mexican Atlantic coast under two sea level rise scenarios for the year 2100. Our objectives were: 1) to identify potentially floodable zones in the face of a sea level rise of one and two meters on the Mexican Atlantic coast with a synthetic model using SRTM and LiDAR topographic data; 2) to determine vegetation and land use affected in the potentially floodable zones; and 3) quantify the vulnerable human population. With topographic data we identified low areas (one and two meters) to assess potentially floodable zones; these were intersected with data layers of vegetation, land use, and human population. Deltaic zones, coastal lagoons and low-lying areas of the Yucatan Peninsula were regions with the largest potentially floodable surface. In the one-meter sea rise scenario, 581,674 ha were identified as potentially floodable, and 896,151 in the two-meter scenario. The most vulnerable vegetation and land use types were wetlands, such as cattail marshes (tulares; ~29 %) and mangroves (~27 %), as well as cultivated grasslands (~6 %). The indirectly affected coastal population could be approximately 5.5 million in these scenarios (~33 %), and the directly affected population could range between 124,000 and 440,000 (~0.72 and 2.55 %, respectively). These results indicate that there will be strong effects in economic, social, and environmental impacts on the Atlantic coast of Mexico in the event of a one- and two-meters sea level rise. This type of work will enable proposal conservation and adaptation strategies for human populations and coastal cities.

Damming effects on hydrological abundance and eco-hydrological alteration in upstream wetlands of Eastern Himalaya

The effects of dams on hydrological conditions and ecological functioning of wetlands downstream are less well studied. Rivers and wetlands are vital environmental elements linked to natural and human ecosystems, so it is extremely important to study ecohydrological planning and human well-being. This study investigates the impact of the dam on the hydrological abundance and eco-hydrological alterations of Loktak Lake, which is located upstream of the Ithai barrage. For this purpose, the Indicator of Hydrological Alteration (IHA) was used to examine the ecohydrological threshold, failure rate, impact magnitude and ecohydrological deficit/surplus in a river section and the adjacent wetland in three temporal phases (I, 1996–2001; II, 2006–2011; and III, 2016–2021). The results show that the hydrological surplus has recently increased to 27.22% (phase III), while in phase I it was only 1.1%. Due to the decreasing failure rate of ecological optima, eco-hydrological surplus was recorded in both Loktak lakes, which is an obvious indication of a reduction in ecological distress that may lead to negative impacts on natural and human well-being. However, due to the constant high-water level in the lake, Phumdi is no longer able to reach the bottom of the lake during the dry season. Since it cannot absorb nutrients, the lake's vegetation declines and rotting sediments settle. Since the Ithai Dam closed the outlet that once connected the lake to the sea, fishermen can no longer dispose of the decomposing biomass. This study is important for dam management and planning to consider the impacts on wetlands downstream and to take measures to mitigate these impacts.

Higher abundance of adult pike in Baltic Sea coastal areas adjacent to restored wetlands compared to reference bays

The abundance of pike, a keystone top-predator, have declined dramatically in the Baltic Sea since the 1990s likely owing to recruitment failure. It has been proposed that wetland restoration can aid the recovery of the pike stock by increasing the number of recruits produced by anadromous populations. Yet, no previous studies have addressed whether wetland restorations are associated with higher abundances of adult pike in the coastal habitat. To address this, we performed standardised rod-and-reel survey fishing in paired bays with and without wetlands across three coastal areas and 3 years. To estimate dispersal and the contribution of wetland pike to the coastal stock, we tagged captured pike with passive integrated responders (PIT) and employed PIT reader stations in wetland inlets. The results showed that pike abundances were on average 90% higher in bays with an adjacent wetland although the effect varied among areas. Moreover, PIT-data uncovered that wetland pike constituted a high proportion of the pike found in adjacent coastal habitats and that some wetland fish dispersed up to 10 km. These results support that wetland restoration is a valuable tool to aid the coastal pike stock and ultimately restore the function and services of the coastal ecosystem.

The main factors and prospects for the restoration of biodiversity in technogenic territories (on the example of the Poltava Mining and Processing Plant)

Mining activities radically change natural ecosystems, the recovery of which is not possible without the restoration of native or transformed communities of autotrophic and heterotrophic organisms. In order to analyze the success of biodiversity restoration using unified methods, an inventory of higher plant flora and avifauna species in the technogenic territories of the Poltava Mining and Processing Plant was carried out. The dominant species identified in mining dumps, tailings, bypass and drainage canals, urban wastewater treatment and bioengineering facilities and on the PMP territory have been studied in detail. The studies were carried out in the spring-summer period of 2021–2022. The avifauna includes 140 species belonging to 18 orders and 45 families (Passeriformes predominate – 62.0%). 103 species nest on the PMP territory, 32 nomadic and 5 transient species are also registered. The nesting avifauna is dominated by representatives of both native nemoral (16.0%, n = 103) and forest-steppe (13.0%) and tropical (14.0%) avifauna. A significant number of birds belong to limnophiles, which prevail in the territories of the urban wastewater treatment plant (66.7%, n = 30) and tailings (62.5%, n = 24). They are also common in the bypass and drainage canals, where hydro- and hygrophilous phytocenoses have formed, similar to floodplain and real meadows as part of adjacent wetland ecosystems. Among the surrounding natural biogeocenoses, there are no steppe ones with their inherent unique floristic composition, which explains the small number of stepants in the studied flora and campophiles in the avifauna. In recovery successions, general patterns were revealed: biogeocenoses surrounding the technogenic territories of the PMP are the main source of producer diasporas and a variety of consumers, which are so necessary for the restoration of degraded landscapes. Phanerophytes from the genera Populus, Pinus, Fraxinus, Ulmus, Morus, Juglans, etc. are determinants in the sylvacenoses formed on the dumps and territories of the plant. Therefore, dendrophiles characteristic of neighbouring pine and floodplain forests, as well as garden phytocenoses in the private sector territory, dominate in the ornithocomplexes. Nationally rare avifauna includes 5 species, two of which nest. Among the identified bird species, the following nesting species are listed in the Red Book of Ukraine: Columba oenas, Himantopus himantopus, as well as transient and nomadic species: Hieraaetus pennatus, Haliaeetus allbicilla, Milvus migrans. The success of the natural formation of plant communities, the rich ornithological complex with the participation of rare species, and the location of the PMP territory within the migration routes indicate the expediency of further research into the possibilities of their inclusion in the nature reserve fund with the status of “territory of renaturalization”.

River Corridor Sources Dominate CO2 Emissions From a Lowland River Network

AbstractRivers and streams are control points for CO2 emission to the air (fCO2), with emission rates often exceeding internal metabolism (net ecosystem production, NEP). The difference is usually attributed to CO2‐supersaturated groundwater inputs from upland soil respiration and rock weathering, but this implies a terrestrial‐to‐aquatic C transfer greater than estimated by terrestrial mass balance. One explanation is that riparian zones—rich in organic and inorganic C but mostly neglected in terrestrial mass balances—contribute disproportionately to fCO2. To test this hypothesis, we measured fCO2, NEP, and the lateral CO2 contributions from both terrestrial uplands (TER) and riparian wetlands (RIP) for seven reaches in a lowland river network in Florida, USA. NEP contributed about half of fCO2, but the remaining CO2 emission was generally much larger than measured TER. The relative importance of RIP versus TER varied markedly between contrasting hydrogeologic settings: RIP contributed 49% of fCO2 where geologic confinement forced lateral drainage through riparian soils, but only 12% where unconfined karst allowed deeper groundwater flowpaths that bypassed riparian zones. On a land area basis, the narrow riparian corridor yielded far more CO2 than the terrestrial uplands (33.1 vs. 1.4 g‐C m−2 yr−1), resulting in river corridors (i.e., stream channel plus adjacent wetlands, NEP + RIP) sourcing 87% of fCO2 to streams. Our findings imply that true terrestrial CO2 subsidies to streams may be smaller than previously estimated by aquatic mass balance and highlight the importance of explicitly integrating riparian zones into the conceptual model for terrestrial‐to‐aquatic C transfer.

Pannon homoki legelők vizsgálata az Ipoly mentén

The results of global climate change can be observed in climate of Hungary. In the last couple of decades significant have been observed extremes in the climate of Europe due to global climate change (IPCC, 2014), which the irregular alternation of droughts and floods could be traced in the Carpathian Basin (Bartholy et al., 2009, 2014). The river floodplains and adjacent wetlands were outstanding from a nature conservation point of view due to the increasingly exposed to this change (Capon et al., 2013). Because of climatic effects, floodplain areas are even more exposed to the spread of invasive species (Szollát and Schmotzer, 2004; Schmotzer, 2008; Füri 2000; Füri and Kelemen 1997; Čížková-Končalová et al. 2013), and changes in land use also aggravate this problem (Mosner, 2015; Penksza et al., 2012). The aim of this study is to present the impact of extreme climatic situations on vegetation in grazed grasslands. The question was, which Festuca species occurs in addition to this? Can Festuca javorkae or Festuca pseudovina be found. The Festuca javorkae, which was related to Festuca rupicola, could also be problematic, although this species was clarified (Penksza, 2000, 2009a; Penksza et al., 2020, 2021; Markgraf-Dannenberg, 1980) and its species differentiation was shown using molecular studies by Bnauer et al. (2003) and Galli et al. (2006). According to the description of association Salvio nemorosae-Festucetum rupicolae, Festuca rupicola is one of the species of the association that appeared in the present study.

Surface water and aerosol spatiotemporal dynamics and influence mechanisms over drylands

Under the background of global warming and excessive human activities, much surface water in drylands is experiencing rapid degradation or shrinkage in recent years. The shrinkage of surface water, especially the degradation of lakes and their adjacent wetlands in drylands, may lead to the emergence of new salt dust storm hotspots, which causes greater danger. In this paper, based on high spatial resolution global surface water (GSW) and multiangle implementation of atmospheric correction (MAIAC) AOD data, we systematically analyze the dynamic characteristics of surface water and aerosols in typical drylands (Central Asia, CA) between 2000 and 2018. Simultaneously, combined with auxiliary environment variables, we explore the driving mechanisms of surface water on the regional salt/sand aerosols on different spatial scales. The results show that the seasonal surface water features an increasing trend, especially a more dramatic increase after 2015, and the permanent surface water indicates an overall decrease, with nearly 54.367 % at risk of receding and drying up. In typical lakes (Aral Sea and Ebinur Lake), the interannual change feature of the surface water area (WA) is that a continuous decrease during the study period occurs in Aral Sea area, yet a significant improvement has occurred in Ebinur Lake after 2015, and the degradation of Ebinur Lake takes place later and its recovery earlier than Aral Sea. The aerosol optical depth (AOD) in CA shows obvious seasonal variation, with the largest in spring (0.192 ± 0173), next in summer (0.169 ± 0.106), and the smallest in autumn (0.123 ± 0.065). The interannual variation of AOD exhibits an increase from 2000 to 2018 in CA, with high AOD areas mainly concentrated in the Taklamakan Desert and some lake beds resulting from lake degradation, including Aral Sea and Ebinur Lake. The AOD holds a similar trend between Aral Sea and Ebinur Lake on an interannual scale. And the AOD over Ebinur Lake is lower than that over Aral Sea in magnitude and lags behind in reaching the peak compared with Aral Sea. The WA change can significantly affect aerosol variation directly or indirectly on the aerosol load or mode size, but there are obvious differences in the driving mechanisms, acting paths, and influence magnitude of WA on aerosols on different spatial scales. In addition, the increase of WA can significantly directly suppress the increase of Ångström exponent (AE), and the effects of WA on AOD are realized majorly by an indirect approach. From the typical lake perspective, the effects of WA on aerosol in Aral Sea are achieved via an indirect path; and the decrease of WA can indirectly promote the AOD rise, and directly stimulate the AE growth in Ebinur Lake.

A synthesis of fauna, palaeoenvironments and stratigraphy of the Miocene Tagay locality (Olkhon Island, Lake Baikal, Eastern Siberia)

We report about the Early Miocene Tagay fauna of Olkhon Island, the largest island of the Baikal Lake. The Tagay fauna is of high scientific importance because of the diversity of fishes, amphibians, lizards, snakes, turtles, manifold birds and mammals. The lithology, geochemistry and the fossil record along the Tagay-1 section allow reconstruction of various palaeoenvironments, i.e. open water, shallow lakes with adjacent wetlands, riverine woodlands, and also forested and dry habitats. The fossil record, lithology and geochemical sediment-analyses suggest a temperate palaeoclimate with short humid and dry periods. The small mammal record and the magnetic polarity pattern of the upper part of section Tagay-1 correlate with the subchrons C5Cn.2r – C5Cn.1r of Chron C5C and the late Burdigalian Stage of the Geologic Time Scale (GTS2000). The corresponding age range of the Tagay fauna is ~16.5 to ~16.3 Ma.

Sediment carbon sequestration and sources in peri-urban tidal flats and adjacent wetlands in a megacity

We investigated the sediment carbon (C) stocks, sequestration and sources in tidal flats and their adjacent mangroves in two coastal wetlands in Hong Kong (the Mai Po Nature Reserve (MPNR) and Ting Kok (TK)), part of a megacity of ∼20 million. At both locations, the C stock of tidal flats was lower than that of mangroves. In MPNR, tidal flats indicated a higher C burial rate (75.2 g C m−2 yr−1) compared to mangroves (64.3 g C m−2 yr−1). The C of tidal flats mainly originated from mangroves and riverine sources, while those in deeper sediments (below 60 cm) in the mangroves originated from the tidal flats. In TK, the C of tidal flats was dominated by oceanic sources. Our study indicates that tidal flats are also important in coastal C sequestration. On highly urbanized coasts, tidal flats and their connected mangroves can play a critical role for C mitigation.

Geological and archaeological heritage in the Mediterranean coasts: Proposal and quantitative assessment of new geosites in SW Sardinia (Italy)

The south-western Sardinian coast (Italy), in the sector between the small village of Chia (Domus de Maria) and the Piscinnì locality (Teulada), is one of the most interesting of the island, being characterized by a wide geodiversity, a complex history testified by several archaeological sites, rich ecosystems, and beautiful landscapes. This area is already famous as a seaside resort, but its rich geological heritage is totally unrecognized and the educational and touristic potential of its archaeological sites is widely undervalued. In this paper, we propose an itinerary in seven stages, each of which selected considering mainly its geology (geodiversity, scientific relevance of the geological features, and educational potential), and also the additional values as the presence of archaeological sites and/or of ecological diversity and/or touristic attractions. The aim of this work is to propose the study area as a geotrail since it represents a valuable geological (and not only) heritage to be protected, preserved, and valorized in the broadest meaning of the word. The following sites have been selected: Chia tower hill, showing interesting geological features and the Punic-Roman archaeological site of Bithia; Campana and Su Giudeu beaches with their dune system and the adjacent wetlands; Settiballas, near to the Chia-Laguna resort displaying a significant geological contact; Capo Spartivento rias and cliffs; Tuerredda beach and sand dunes; Capo Malfatano, a panoramic promontory made up of 460 million years old metamorphic rocks; and Piscinnì area, where a beautiful beach and a wide Punic/Roman sandstone quarry can be observed. In addition, the most panoramic points are overlooked by Spanish towers built during the 16th to 17th century. The study area is described from geological and archaeological points of view, after a detailed field survey, the petrographic characterization of the main rocks, and an overview of the scientific literature. The quantitative assessment of the geosite values has been also performed, revealing the high potential for scientific, educational, and touristic purposes. The main concerns related to the preservation and valorization of this geosite are also addressed. Finally, a discussion on the geosite assessment methods is proposed to contribute to the scientific literature on the geoheritage. The site-by-site description is reported at the end of the paper to be used as a field guide.

Fire intensity and ecosystem oligotrophic status drive relative phosphorus release and retention in freshwater marshes

AbstractEcosystems have been shaped by fire for millions of years. Many oligotrophic ecosystems rely on fire for biogeochemical cycling and maintenance of key processes. However, it is uncertain how fire intensity interacts with nutrient limitation to drive differential responses in postfire biogeochemical cycling and ecosystem recovery. In this study, we compare pre‐ and postfire carbon and nutrient pools in two adjacent wetlands characterized by either lower or higher phosphorus (P) inputs and thus different levels of P limitation. Carbon (C), nitrogen (N), and P pools and litter and root decomposition rates were measured starting 1 year prefire until 1 year postfire in lower‐P (LP) and higher‐P (HP) freshwater marshes of the Florida Everglades. Dominant vegetation biomass and vegetation composition were monitored as well. Fire energy release was measured to link the causal mechanism, heat transfer, to nutrient fluxes. We observed temporary increases in surface water, periphyton, and leaf tissue P concentrations in both wetland types following fire. Soil P increased and soil C:P and N:P ratios decreased postfire in the LP wetland but did not change in the HP wetland. Prefire soil P was greater in the HP than the LP wetland, but did not differ 1 month or 1 year postfire. Vegetation structure and composition were marginally affected by fire. Fire intensity was highly variable within both wetlands. Increasing fire intensity correlated with increasing accumulation of soil organic matter in the LP wetland, and with increases in decomposition rates in both wetland types, between pre‐ and postfire. Litter and root decomposition rapidly increased with increasing fire intensity, but seemed to stabilize after a certain fire intensity threshold was reached. Our results indicate that fire can temporarily ease P limitation in oligotrophic wetlands, by affecting soil nutrient stoichiometry and organic matter processing, while maintaining vegetation community composition. Further, we identified fire dosing, expressed as the fire radiative energy release, to be an effective control of postfire biogeochemical cycling. Hence, nutrient management should be incorporated into burn prioritization tools and, when applying prescribed fires, natural resource managers should also consider how fire attributes, such as fire intensity, impact nutrient cycling and other soil processes.

Enriching our knowledge of Late Cretaceous wetland plant communities: Zlatkovia crenulata gen. et sp. nov., an amphibious angiosperm from the St. Mary River Formation, Alberta, Canada

Sixty-seven coalified compression specimens of leaves, one attached to a stem, have been found in the St. Mary River Formation (uppermost Campanian–lowermost Maastrichtian, Upper Cretaceous) near Cardston, Alberta, Canada. Leaves have long multi-veined petioles with clasping bases, and an ellipsoid to obovate lamina with a convex to almost flat apex, and a crenate margin with one order of convex-convex chloranthoid teeth with angular sinuses. Tooth apices often end in a small concavity interpreted as a hydathode. Several primary veins enter the lamina in a flabellate manner. The central primary vein branches pinnately while lateral primaries, dichotomize toward the margin producing a reticulodromous pattern of secondaries. Secondaries arising from the lateral primary veins are the result of consistent dichotomies and anastomoses with a concurrent loss of gauge. Tertiary veins are alternate percurrent, and quaternaries form an irregular reticulate fabric. Quaternary veins form polygonal areoles with freely ending veinlets. Some specimens show a polygonal pattern of sub-epidermal aerenchyma like that of many other aquatics. Plants are compared to other fossil aquatic taxa, including those from the St. Mary River Formation and extant members of Ranunculaceae, Menyanthaceae and Nymphaeaceae. The specimens are described as a new amphibious aquatic: Zlatkovia crenulata Rothwell & Stockey gen. et sp. nov., eudicot family incertae sedis. This assemblage meaningfully enriches our understanding of aquatic and adjacent wetland habitats near the close of the Cretaceous, and emphasizes that the structure of modern wetland communities was well established before the end of the Mesozoic.

Spatial and Temporal Patterns of Shorebird Assemblages in Select Estuaries along the India's West Coast

The Indian coast and its adjacent wetlands host large congregations of shorebirds, including winter and passage migrants of high conservation priority, along the Central Asian Flyway. Identifying crucial wintering and stopover sites and seasons is an important step toward conserving shorebirds and their habitats along the Indian coast. We assessed spatial and temporal patterns of shorebird composition from January 2015 to December 2016 at seven estuaries along Maharashtra's Sindhudurg district, which is located on India's west coast, a coastal zone of international importance for shorebirds. Three potential shorebird habitats –mangroves, mudflats, and sandy beaches – were selected at each of the estuaries chosen for the study. We established three vantage points, one each in the mangrove, mudflat, and sandy beach areas, to count birds during low tide. The total count method was followed to count birds, and occasional photograph-based counts were also made when flock size was big or the flocks kept changing. We recorded 31 species of migratory shorebirds, of which 68% wintered and 32% used the Sindhudurg coast as migratory stopover site. We found significantly high richness and abundance of shorebirds during winter and in the mudflats. nMDS was used to determine species composition of shorebird across habitats and months and revealed distinct patterns of composition in five unique phases: arrival, wintering, early departure, departure, and breeding. Our results revealed that the species composition of shorebirds is not homogenous across sites and months, and is largely driven by the habitat heterogeneity of estuaries, seasonality, and anthropogenic disturbances. These results provide baseline information on shorebirds along a stretch of India's west coast and highlight the importance of mudflats and non-protected coastal wetlands for shorebirds.

Effects of Roach Rutilus rutilus Collapse on Abundance, Distribution and Diet of Great Cormorants Phalacrocorax carbo in a Large River in North-West Europe

Aquatic habitats are subject to multifactorial changes including global warming, invasive species colonisation, modification of organic and micro-pollutant discharge and, for large rivers in Europe, drastic physical modification (e.g. channelisation, impoundments). The Meuse River in Belgium is one of these multi-stressed environments, in which recent decreases of fish populations were observed, with the loss of 90% of Roach Rutilus rutilus biomass in only a few years. In the light of this fish stock collapse, diet modification and local population evolution of a key avian predator, the Great Cormorant Phalacrocorax carbo, were examined. The diet composition and daily consumption rates of the Great Cormorants feeding in the river were largely similar to that seen before the fish population collapsed. Numbers of wintering Great Cormorants decreased by 90%, as did Roach numbers, and thus the predation pressure was adjusted to the decreased fish availability. The number of night-roosts and locations remained unchanged and no redistribution to adjacent habitats was observed at the regional scale. We suggest a bottom-up chain of responses where a fish collapse forced a reduction in Cormorant numbers, being the main piscivorous avian predator, rather than a modification of Cormorant prey composition and/or a local redistribution to adjacent wetlands (top-down). The factors that govern the establishment of a small and productive breeding population remain to be explained, but we hypothesise that the start of breeding could well have been alleviated by the large decrease in number of wintering birds.

Capabilities of the WEBBIRDS system in the process of assessing the impact of wind farms on seasonal bird complexes on the example of spring migrants at the Botiieve wind farm in 2013-2021

This paper contains the analyzed results of field observations of the spring migration of birds on the territory of the Botiieve wind farm in 2013-2021. The work was carried out as part of the planned monitoring of the ornithological situation in the area of the Botiieve wind farm (Pryazovskyi district, Zaporizhzhia region) and also covered the Tubal Estuary formed by the confluence of the Velyka and Mala Domuzla and Akchokrak Rivers and in the mouth of the Korsak River. During each trip, up to 70% of the wind farm area was covered. There were given characteristics of the taxonomic composition of the ornithocomplex, flight phenology, height and direction of migration by seasons and months. In the spring period of 2013-2021, 156,910 individuals of 125 species were recorded in the project area. 52,575 individuals of 92 species of these birds (33.5%) were observed directly within the Botiieve wind farm and buffer zones and there were recorded 104,335 individuals of 99 species (66.5%) at the adjacent wetlands - the Botiieve Ponds and the Tubal Estuary. New methods for collecting, storing and processing information, including mapping, server storage and data processing using two web applications, have been proposed. In order to describe in detail the migration processes in the local area, methods of vector mathematics, as well as computer vision algorithms, were used. The result of the analysis was a gradient map of seasonal bird migration concentration, which allows a differentiated approach to assessing the threats to birds from operating wind turbines. The impact of the Botiieve wind farm on birds during the period of seasonal migrations is estimated to be low.

Charting the Plantation Landscape from Natchez to New Orleans ed. by Laura Kilcer VanHuss

Reviewed by: Charting the Plantation Landscape from Natchez to New Orleans ed. by Laura Kilcer VanHuss Robert K. Nelson Charting the Plantation Landscape from Natchez to New Orleans. Edited by Laura Kilcer VanHuss. Reading the American Landscape. (Baton Rouge: Louisiana State University Press, 2021. Pp. [x], 243. $45.00, ISBN 978-0-8071-7479-1.) In a recent interview with Fast Company (August 4, 2020), celebrity Ryan Reynolds offered an apology for holding his wedding at a plantation. "What we saw at the time was a wedding venue on Pinterest," he explained. "What we saw after was a place built upon devastating tragedy." The seven essays in Charting the Plantation Landscape from Natchez to New Orleans probe the lingering disconnect between the popular imagery of grand plantation estates and the material realities of agroindustrial labor camps of enslaved people. The collection uses something more historically germane than a Ryan Reynolds interview as its framing device: Marie Adrien Persac's 1858 Norman's Chart of the Lower Mississippi River. Persac's map not only delimits the volume's geographic focus but also exemplifies the ongoing work of white elites before and after emancipation to project an image of social order and beauty that ignored or denied the harsh realities of enslavement. The lead essay, Laura Ewen Blokker's "Construction and Construct: Architecture of the Louisiana Plantation," frames these issues admirably. Blokker argues that as sugar production came to dominate the lower Mississippi River Valley in the [End Page 386] nineteenth century, the "organic spatial relationships" of earlier Creole plantation architecture were replaced by "rigid geometries" laid out to optimize commodity production (p. 22). These new architectural patterns distanced the domestic world of enslavers from the slave cabins and sugarhouses, a distancing that for two centuries was utilized to focus attention on aristocratic leisure and away from the enslaved labor that sustained it. Christopher D. E. Willoughby's excellent essay, "Plantations as Landscapes of Medicine," analyzes how antebellum racial science was used to project an image of the Deep South as healthy and its hot, humid climate as ideally suited for Africans' supposed biology. The reality he catalogs could not have been more at odds with this racial imaginary. Adjacent wetlands, forests, and global trade routes brought diseases from near and far—cholera, yellow fever, malaria. Sugar and cotton production regularly resulted in industrial accidents that literally cost the lives and limbs of the enslaved; unceasing reproduction resulted in gynecological ailments. Another strong essay, Christopher Morris's "The Rise and Fall of Uncle Sam Plantation," puts the lie to the fecundity of the plantation landscape. Backbreaking labor by the enslaved resulted in impressive feats of water control that transformed forests and swamps into sugarcane fields. But this work exacted a devastating environmental toll that deprived the land of fertilizing silt, exposed the soil to erosion, and made plantations vulnerable to destructive flooding. The collection includes two essays focused on politics: one by Charles D. Chamberlain III on the maneuvering of the Whig Creole plantation elite, the other by William Horne analyzing how both freedpeople and their former enslavers "weaponized" the plantation landscape as they vied with one another for political power during Reconstruction (p. 131). Jochen Wierich's essay focuses on how artistic representations of plantations of the lower Mississippi Valley changed dramatically between emancipation and the Depression. An essay by Suzanne Turner reads the gardens of both enslavers and the enslaved as expressions of their respective cultural identities and heritage. The introduction to the volume says that it aims to make "material normally reserved for academic discussions accessible to the general reader" (p. 9). It might be too much to hope that this collection will find much readership beyond the academy. But it certainly will be of interest and value to scholars of Louisiana, slavery, and landscape architecture. And if it ends up being picked up in a plantation gift shop by an occasional layperson, that is all to the good. Robert K. Nelson University of Richmond Copyright © 2022 The Southern Historical Association

Spatial Mapping of Dissolved Gases in the Danube Delta Reveals Intense Plant-Mediated Gas Transfer

Global estimates see river deltas and estuaries contributing about equally to CO2 and CH4 emissions as lakes and reservoirs, despite a factor 6 smaller surface area. Assessing the horizontal gradients in dissolved gas concentrations from large river reaches to connecting canals and wetland lakes remains a challenge in many deltaic systems. To elucidate the processes affecting local CO2 and CH4 concentrations in the Romanian part of the Danube Delta, we mapped dissolved O2, N2, He and Ar using a portable gas-equilibration membrane-inlet mass spectrometer (GE-MIMS), along with CO2, CH4, water temperature and conductivity. We measured the concentrations along the aquatic continuum from a small houseboat during two campaigns, in spring and autumn, to capture different hydrological and plant growth conditions. Delta-scale concentration patterns were comparably stable across seasons. Small connecting channels were highly influenced by the riparian wetland, which was strongest in the eastern part of the biosphere reserve. These sites represented the delta’s CO2 and CH4 hotspots and showed clear signs of excess air, i.e., supersaturation of dissolved noble gases with respect to air-saturated water. As the adjacent wetland was permanently inundated, this signal was likely caused by root aeration of Phragmites australis, as opposed to traditional excess air formation via water table fluctuations in the unsaturated zone. The special vegetation setting with reed growing on floating peat coincided with the highest CO2 and CH4 concentrations (>700 μmol/L CO2 and 13 μmol/L CH4, respectively) observed in an adjacent channel. Shallow lakes, on the other hand, were major sites of photosynthetic production with O2 oversaturation reaching up to 150% in spring. The observed deficit in non-reactive gases (He, Ar and N2) indicated that the lakes were affected by O2 ebullition from macrophytes. According to our estimations, this ebullitive flux decreased O2 concentrations by up to 2 mg/L. This study highlights the effect of plant-mediated gas transfer on dissolved gas concentrations and supports recent studies stressing the need to account for ebullitive gas exchange when assessing metabolism parameters from O2 in shallow, productive settings.

Improving Channel Hydrological Connectivity in Coastal Hydrodynamic Models With Remotely Sensed Channel Networks

AbstractCoastal wetlands are nourished by rivers and periodical tidal flows through complex, interconnected channels. However, in hydrodynamic models, channel dimensions with respect to model grid size and uncertainties in topography preclude the correct propagation of tidal and riverine signals. It is therefore crucial to enhance channel geomorphic connectivity and simplify sub‐channel features based on remotely sensed networks for practical computational applications. Here, we utilize channel networks derived from diverse remote sensing imagery as a baseline to build a ∼10 m resolution hydrodynamic model that covers the Wax Lake Delta and adjacent wetlands (∼360 km2) in coastal Louisiana, USA. In this richly gauged system, intensive calibrations are conducted with 18 synchronous field‐observations of water levels taken in 2016, and discharge data taken in 2021. We modify channel geometry, targeting realism in channel connectivity. The results show that a minimum channel depth of 2 m and a width of four grid elements (approximatively 40 m) are required to enable a realistic tidal propagation in wetland channels. The optimal depth for tidal propagation can be determined by a simplified cost function method that evaluates the competition between flow travel time and alteration of the volume of the channels. The integration of high spatial‐resolution models and remote sensing imagery provides a general framework to improve models performance in salt marshes, mangroves, deltaic wetlands, and tidal flats.