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Large earthquakes can instantaneously reshape coastal landforms owing to fault zone ruptures that uplift the Earth’s surface. On January 1, 2024, in the north of the Noto Peninsula, central Japan, an Mj7.6 (Mw7.5) earthquake occurred, triggering coastal uplift of up to 4 m. To measure the resulting shoreline advance, we analyzed orthophotos taken before and after the earthquake, focusing on two bays in the northwest of the Noto Peninsula where the largest uplift occurred. In response to the uplift, the shoreline advanced by up to 200 m, increasing the total area of the coastal plains by 0.46 km2. The maximum shoreline extension occurred in the midsection of both bays, while the extension at the edges was less than 20 m, possibly reflecting the shoreface topography and bathymetry existing before the uplift. The uplift exposed previously undersea rocks, forming new coastal plains and extending river channels. Our results indicate that coastal landforms such as sandy beaches, coastal plains, shore platforms, and the sediment budgets of feeding drainage systems were substantially altered by this earthquake, and a long recovery period is anticipated. Our findings serve as a crucial benchmark for tracking future changes in shorelines in response to coastal landform adjustments. [ABSTRACT FROM AUTHOR]

The scarcity of freshwater resources in coastal plains has raised global concerns. Understanding the chemical characteristics and evolution of groundwater in coastal plains is crucial for ensuring sustainable water supply for residents and irrigation. This study focuses on a representative profile of the Luanhe plain, systematically analyzing hydrochemistry and stable isotopes of seawater, river water, and groundwater samples to elucidate groundwater chemistry evolution and investigate the influence of evaporation and mixing processes. Results showed that shallow groundwater was predominantly of the Ca-HCO3 type, formed through the dissolution of halite, carbonate, and silicate minerals in the aquifer. Under the influence of evaporation and mixing processes, there was a transition in the chemical type towards Ca-Na-HCO3 type. Especially in areas influenced by seawater intrusion at estuaries, a rapid shift towards Na-Cl type occurred. In addition, deep aquifers evolved predominantly into Ca-HCO3 type groundwater through the leaching of silicate and carbonate minerals within the aquifer matrix. Along the flow path, influenced by cation exchange and mixing processes, the water chemistry underwent a shift from the Ca-HCO3 type to the Na-HCO3 type. The river water chemistry was primarily influenced by evaporation and the erosion of silicate and sulfate minerals from the riverbed. At estuarine zones, intense seawater intrusion significantly increased salinity and shifted the water chemistry from a Ca-Cl type to a Na-Cl type. This study elucidated the evolution mechanisms and influencing factors of coastal groundwater chemistry, providing scientific insights for local groundwater resource management. [ABSTRACT FROM AUTHOR]

In coastal plains, saline water intrusion (SWI) and potentially hazardous pollutants are harmful to local human health. The southern Laizhou Bay has become a typical representative of the northern silty coast due to its extensive silt sedimentation and the significant impact of human activities. This research focuses on a portion of the southern Laizhou Bay, using GIS-based spatial analysis, water quality index methods and health risk assessments to evaluate the impact of saltwater intrusion and potential hazardous pollutants. The results show that the groundwater in the study area is significantly impacted by saline water intrusion, leading to major ion concentrations that far exceed World Health Organization (WHO) standards. The groundwater chemical types of brine and brackish water in the study area are mainly Cl-Na, and the main chemical types of fresh water are HCO3-Ca·Na. The average concentration sequence of the main ions in groundwater is K+ > HCO3− > Cl− > Na+ > SO42− > Ca2+ > Mg2+. The average hazard quotient (HQ) sequence in typical pollutants is Cl− > F− > NO3-N > Se > Mn > NO2-N > Cu > Pb > Zn > Fe, and the carcinogenic risk (CR) sequence caused by carcinogenic heavy metals is Cd > As > Cr. The noncarcinogenic health risk area is mainly distributed in the northwest of the study area, while the potential carcinogenic risk area is in the central region. The Cl is the greatest noncarcinogenic risk to adults and children. The mean HQ values for adults and children were 95.69 and 146.98, indicating a significant noncarcinogenic risk. The mean CR values for adults and children were 0.00037 and 0.00057, suggesting a relatively low carcinogenic risk. SWI is the main influencing factor on human health; therefore, it is necessary to prevent and control SWI. Moreover, potentially hazardous pollutants are carcinogenic and noncarcinogenic risks and are caused by agriculture, industry and other human activities. The findings of this research offer scientific insights for groundwater pollution control and saline water intrusion management in similar coastal areas. [ABSTRACT FROM AUTHOR]

Abstract Large earthquakes can instantaneously reshape coastal landforms owing to fault zone ruptures that uplift the Earth’s surface. On January 1, 2024, in the north of the Noto Peninsula, central Japan, an Mj7.6 (Mw7.5) earthquake occurred, triggering coastal uplift of up to 4 m. To measure the resulting shoreline advance, we analyzed orthophotos taken before and after the earthquake, focusing on two bays in the northwest of the Noto Peninsula where the largest uplift occurred. In response to the uplift, the shoreline advanced by up to 200 m, increasing the total area of the coastal plains by 0.46 km2. The maximum shoreline extension occurred in the midsection of both bays, while the extension at the edges was less than 20 m, possibly reflecting the shoreface topography and bathymetry existing before the uplift. The uplift exposed previously undersea rocks, forming new coastal plains and extending river channels. Our results indicate that coastal landforms such as sandy beaches, coastal plains, shore platforms, and the sediment budgets of feeding drainage systems were substantially altered by this earthquake, and a long recovery period is anticipated. Our findings serve as a crucial benchmark for tracking future changes in shorelines in response to coastal landform adjustments.

Lecidea varians is among the most common and abundant bark-dwelling crustose lichens in temperate eastern North America. As presently delimited, it is highly variable, including chemical and morphological diversity well beyond that currently accepted for most lichen species. The generic placement of L. varians has also been questioned for decades. It has long been recognized as aberrant in Lecidea and Pyrrhospora, excluded from Lecidella, and more recently transferred to Traponora. Drawing from the results of extensive chemical, molecular phylogenetic and morphological studies, we show that L. varians and its relatives represent a previously unrecognized lineage within the speciose lichen family Lecanoraceae. The lineage appears to occupy an isolated position, distinct from the aforementioned genera, and is newly described as the genus Xanthosyne (typified by L. varians). The chemical and morphological variation within L. varians is mirrored by, but not entirely correlated with, considerable molecular diversity. A new taxonomy is proposed for L. varians and its relatives to serve as a framework for future studies. Three species are recognized: X. varians (≡ Lecidea varians), common and widespread in parts of North America; X. granularis, a new species from the Atlantic Coast of eastern North America that differs morphologically from X. varians in having a leprose thallus; and X. sharnoffiorum, a new species also found mainly along the Atlantic Coast of eastern North America, which has a coarsely granular, non-leprose thallus and produces a unique, unidentified xanthone. Multiple well-supported lineages were recovered within X. varians that correlate to varying degrees with chemical and morphological variability, as well as geographic distribution. Eight subspecies are recognized to accommodate the variation within X. varians: X. varians subsp. exigua comb. nov. (≡ Lecidea exigua) characterized by the presence of atranorin and a consistent set of three xanthones, is widespread in southern Europe and western North America (coastal California); X. varians subsp. varians (≡ Lecidea varians) is distributed mainly in northeastern North America and produces thuringione and arthothelin; X. varians subsp. morsei subsp. nov. is morphologically and chemically variable, with one chemotype (thiophanic acid) with a northeastern distribution, and the other with a unique and unidentified xanthone, found mainly in the interior U.S.A.; X. varians subsp. obscura subsp. nov. occurs mainly in the central U.S.A. and North Temperate regions, produces a unique, unidentified xanthone and generally has black apothecia with green epihymenial pigments; X. varians subsp. pseudomorsei subsp. nov. and X. varians subsp. submorsei subsp. nov. resemble X. varians subsp. morsei but differ in molecular sequence characters; X. varians subsp. subtilis comb. nov. (≡ Lecidea subtilis) and X. varians subsp. subexigua subsp. nov. occur in the Appalachian Mountains, the former producing atranorin and the latter lacking atranorin, both with thiophanic acid with or without other xanthones. In an addendum, Lecidella subviridis is discussed with respect to the genus Xanthosyne. An identification key is provided for all species and their subspecies within Xanthosyne. [ABSTRACT FROM AUTHOR]

Soil salinization hinders sustainable agricultural development in coastal regions. Developing a multi-layer soil salinity inversion model and accurately predicting water demand for salt regulation are essential for improving soil salinity management. Wudi County in Shandong Province was selected as the research area, with 79 sampling sites chosen. Soil salinity was measured at the surface (0–20 cm), middle (20–40 cm), and bottom (40–60 cm) layers. Vegetation and salinity indices were extracted from Landsat 8 remote sensing imagery to estimate surface soil salinity. A correlation-based inversion method was developed to obtain multi-layer soil salinity data by leveraging the strong correlation between adjacent soil layers. The water requirement for salt regulation was optimized and predicted by integrating the results from multi-layer soil salinity estimation with Groundwater Management System (GMS) software. The results indicated that the surface layer soil salinity inversion model performed well, with an R2 > 0.75 and an RMSE < 0.43 g/kg for both the training and validation sets. Additionally, the prediction accuracy of the correlation-based inversion method exceeded that of the direct modeling approach, with the middle and bottom layer soil salinity models achieving an R2 > 0.6 and an RMSE < 1 g/kg. Soil salinization in the study area was more severe in the northeast than in the southwest, with both measured and estimated data showing similar spatial distributions. Over the past decade, the overall trend of soil salinization has shown a general decline with localized intensification. The salt distribution patterns in saline soil profiles were predominantly homogeneous and bottom-accumulated. The projected water demand for salt regulation calculated from the estimated data was slightly lower than the actual measurements, yet their spatial distribution was nearly identical. This study provides a scientific foundation for the dynamic monitoring and precise management of soil salinity in coastal regions.

Abstract This work is mainly concerned with the effect of anthropogenic activities and natural radioactivity due to the presence of highly radioactive black sand spots, factory construction, and shipping, in addition to other activities like agriculture on human beings. Forty samples were collected along Baltim–El Burullus coastal plain to detect the effect of these problems and determine the suggested solutions. The black sand of the Baltim–El Burullus coastal plain exhibits a considerable amount of economically heavy minerals, their ratio relative to the bulk composition in the investigated samples ranges from 3.18 to 10.5% with an average of 5.45%. The most important of them are magnetite, ilmenite, rutile, leucoxene, garnet, zircon and monazite. The existence of some radioactive-bearing accessory mineral deposits like zircon and monazite led to measuring the naturally occurring radionuclides 226Ra, 232Th and 40K to evaluate the excess lifetime cancer risk (ELCR). The results showed that these concentrations are 19.1 ± 9.73, 14.7 ± 9.53 and 211 ± 71.34 Bq kg−1 were lower than the corresponding reported worldwide average of 35, 45, and 412 Bq kg−1 for each radionuclide (226Ra, 232Th, and 40 K). The gamma hazard indices such as absorbed dose rate (Dair), the annual effective dose (AED), and excess lifetime cancer risk (ELCR) factor were computed in the investigated sediments and all the results were found (Dair = 26.4 nGy h−1, AED = 0.03 mSv year−1, ELCR = 0.0001) to be lower than the values suggested by the United Nations Scientific Committee on the effect of Atomic Research (59 nGy h−1, 0.07 mSv year−1 and 0.0029 for Dair, AED and ELCR, respectively). The study suggests that the black sand is safe to use in various infrastructure applications at Baltim–El Burullus coastal plain. The levels of radioactivity are not high enough to pose a risk to human health.

This work is mainly concerned with the effect of anthropogenic activities and natural radioactivity due to the presence of highly radioactive black sand spots, factory construction, and shipping, in addition to other activities like agriculture on human beings. Forty samples were collected along Baltim–El Burullus coastal plain to detect the effect of these problems and determine the suggested solutions. The black sand of the Baltim–El Burullus coastal plain exhibits a considerable amount of economically heavy minerals, their ratio relative to the bulk composition in the investigated samples ranges from 3.18 to 10.5% with an average of 5.45%. The most important of them are magnetite, ilmenite, rutile, leucoxene, garnet, zircon and monazite. The existence of some radioactive-bearing accessory mineral deposits like zircon and monazite led to measuring the naturally occurring radionuclides 226Ra, 232Th and 40K to evaluate the excess lifetime cancer risk (ELCR). The results showed that these concentrations are 19.1 ± 9.73, 14.7 ± 9.53 and 211 ± 71.34 Bq kg−1 were lower than the corresponding reported worldwide average of 35, 45, and 412 Bq kg−1 for each radionuclide (226Ra, 232Th, and 40 K). The gamma hazard indices such as absorbed dose rate (Dair), the annual effective dose (AED), and excess lifetime cancer risk (ELCR) factor were computed in the investigated sediments and all the results were found (Dair = 26.4 nGy h−1, AED = 0.03 mSv year−1, ELCR = 0.0001) to be lower than the values suggested by the United Nations Scientific Committee on the effect of Atomic Research (59 nGy h−1, 0.07 mSv year−1 and 0.0029 for Dair, AED and ELCR, respectively). The study suggests that the black sand is safe to use in various infrastructure applications at Baltim–El Burullus coastal plain. The levels of radioactivity are not high enough to pose a risk to human health. [ABSTRACT FROM AUTHOR]

ABSTRACTThis paper presents a 1:20,000 scale Geoarchaeological map of the Cornia river coastal plain in southern Tuscany. The Geoarchaeological map integrates a comprehensive dataset of geomorphological and archaeological features. The spatial relationships between landforms and archaeological records show that the settlement pattern from the VII century BC to the V century AD was mostly influenced by the presence of several depositional landforms which formed before the period under consideration. Integrating the outputs of geomorphological and topographical analyses with archaeological databases is also helpful for land planning, especially in areas where present-day anthropic exploitation needs predictive and valid tools to assess the archaeological hazard.

The genus Castanea, divided into seven extant species of trees worldwide, includes the American chestnut, C. dentata. This once common North American tree has been nearly eliminated from the landscape due to the appearance of chestnut blight early in the Twentieth Century. Castanea has a long history as a component of palynological assemblages, though megafossil paleobotanical remains are quite rare. The distributions of what are believed to be Castanea pollen as they have been derived from coastal plain and near-shore sediments dating back to the Neogene of the coastal plain of the southeastern US are discussed. The abundances of Castanea pollen in microfossil preparations are carefully considered relative to the concept of 'pollen sum' and while it appears that the trees were quite abundant as components of coastal woodlands during the Neogene, the actual number of pollen we found in samples is quite low. American chestnut trees continued to be important into the late Pleistocene and through the time when humans first occupied both coastal and inland areas of the southeastern US. [ABSTRACT FROM AUTHOR]

One benefit of cover cropping is nutrient provision, which can be optimized by management practices to synchronize nutrient releases from residue decomposition with the demands of subsequent cash crops. In the present study, we investigated how termination timing affects the decomposition of cereal rye (Secale cereale L.) residues and the release of associated nutrients. Field experiments were conducted in 2019 and 2020 in typical Ultisols of the Southeastern U.S. with soybean (Glycine max L.) and corn (Zea mays L.) rotation. Cover crops were drill-seeded and terminated 1-, 2-, 3- and 4-week before cash crop planting. Litter bag method and a two-parameter exponential decaying model were applied to estimate residue decomposition and nutrient releases. In 2019, cover crop biomass production ranged from 5757 to 6520 kg ha−1, which was not affected by termination timing. In contrast, cover crop biomass increased when delaying termination by 1 week in 2020. Cover crop provided up to 82 kg nitrogen (N) ha−1, 15 kg phosphorous (P) ha−1, and 89 kg potassium (K) ha−1 in 2019. As expected, terminating cover crops at 1-week intervals resulted in different decomposition rates but imposed inconsistent effects on N, P, and K releases. There was no difference in N, P, and K content in cash crops. However, cover cropping resulted in higher corn yields than control plots when terminated at 4-week before corn planting. The results suggested that cover crops can have significant nutrient benefits in the tested soils and climatic conditions, but optimal management is the key to realizing the potential. [ABSTRACT FROM AUTHOR]

This research targets disentangling shallow causes of anthropogenically induced subsidence in a reclaimed and urbanized coastal plain. The study area is the city of Almere, in the South Flevoland polder, the Netherlands, which is among the countries' fastest subsiding areas. The procedure consists of integrating Interferometric Synthetic Aperture Radar (InSAR) data with high‐resolution phreatic groundwater and lithoclass models, and a database containing construction details. The InSAR data were derived from Sentinel‐1, one ascending and one descending track, over a period from March 2015 until June 2020. The two main parts of the workflow are isolation of the InSAR points of structures without a pile foundation and a data assimilation procedure. The shrinkage of surficial clay beds by phreatic groundwater level lowering is identified as the main cause of subsidence in the area, with an average contribution of 6 mm per year. The history‐matched physics‐based model predicts that 1 m drop in phreatic groundwater level now translates into 10 mm of subsidence in the next 5 years. Additionally, a groundwater deficiency due to severe dry periods should be considered as an accelerator of subsidence. To ensure a robust network to estimate subsidence, we recommend a consistent monitoring strategy of the phreatic groundwater level. Plain Language Summary: The city of Almere, in the Netherlands, is part of a polder that was reclaimed in 1968. Land reclamation is accompanied by the lowering of groundwater levels, which can cause land subsidence. Almere is situated on top of about 9 m of soft soil layers. These layers were deposited after the last ice age and consist predominantly of clay and peat. It is important to understand and quantify the subsidence processes in these Holocene layers, to be able to mitigate subsidence. By lowering the groundwater level, the soft soil layers are dried. Clay shrinks when it dries out and organic material (within peat) oxidizes. Lowering the groundwater level also causes the load of the layers below to increase, which can result in the compaction of the layers (reduction in size by pressing together). This study targets the behavior of these processes. Results of our study indicate that the shrinkage of clay is the dominant driver of subsidence in Almere. One meter lowering in groundwater level now results in approximately 1 cm subsidence in 5 years. To improve our understanding of the non‐trivial link between groundwater fluctuations and subsidence, higher spatial‐temporal resolution groundwater monitoring is required. Key Points: Interferometric Synthetic Aperture Rader data on objects constructed on soft soil without a foundation are used for subsidence measurementsShrinkage of clay by aeration as a result of artificially lowered phreatic groundwater levels is identified as the main source of subsidenceOne meter drop in phreatic groundwater level now translates into 1 cm of subsidence in 5 years [ABSTRACT FROM AUTHOR]

A new species, Hypothyce rayi MacGown & Hill, sp. nov. (Coleoptera: Scarabaeidae: Melolonthinae: Melolonthini), is described from east central Alabama, USA. Three other species of Hypothyce, H. burnei Skelley, H. mixta Howden and H. osburni (Cartwright) are known to occur in the United States. We discuss differences between these species and provide an updated identification key to the genus. [ABSTRACT FROM AUTHOR]

The complex relationship between Bedouins and Zionist pioneers in the Land of Israel during the late 19th and early 20th centuries evolved along two parallel tracks: conflict and cooperation. The former was a corollary of the sociocultural gap between the pioneers and the Bedouins and revolved by and large around the diametrically opposed views regarding land ownership rights and their implications (e.g. access to water, grazing). The latter was a result of the growing Bedouin realisation that the Zionist project was there to stay: the more the Jewish pioneers proved their determination to cultivate their lands and defend themselves the more they won Bedouin respect, or at least grudging acquiescence, which in turn evolved to wider recognition of the vast socioeconomic benefits of peaceful coexistence. [ABSTRACT FROM AUTHOR]

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Subsurface fluvial deposits in coastline‐proximal settings record the spatiotemporal evolution of the coastal landscape and may be viable repositories of sediment for future coastal restoration projects. However, quantitative linkages between the geomorphic form and stratigraphic expression of coastal plain fluvial elements remain lacking, complicating coastal stratigraphic interpretations and subsurface resource assessment. This study explores the expression and preservation of fluvial coastal plain geomorphic features through outcrop‐scale seismic stratigraphic analysis of ultra‐high‐resolution chirp acoustic reflection data from the north‐western Gulf of Mexico inner continental shelf, offshore the Brazos River, Texas, USA. The chirp data exhibit decimetre‐scale vertical resolution within the upper 35 m of the shelf, evincing the preservation of two distinct types of coexisting fluvial channel‐forms: Type 1, a 1 km wide and 9 m deep single‐storey channel belt filled with sand‐rich lateral accretion deposits and channel fills; and Type 2, numerous 10 to 800 m wide and 1 to 20 m deep incisional floodplain channels filled with extensive drapes of overbank‐derived sediments. The chirp data resolve fluvial geomorphic elements including lateral accretion surfaces, levées, floodplain deposits and abandoned channel fills. Rollover of lateral accretion surfaces, widespread draping of seismic reflectors within channel fills, and quantitative comparison between the interpreted stratigraphic forms and analogous features on the nearby Texas Coastal Plain suggest near‐complete stratigraphic preservation of the geomorphic form of both channel belt and floodplain channel elements. Rapid aggradation of the coastal plain by the Brazos River in this region during the Holocene transgression is hypothesized as a mechanism for the high degree of preservation achieved. This study proposes the first recognition criteria for the seismic stratigraphic expression of coastal floodplain channels and provides direct linkages between the geomorphic and stratigraphic expression of a coastal plain fluvial landscape, promoting improved coastal stratigraphic interpretations and assessment of subsurface lithofacies distributions. [ABSTRACT FROM AUTHOR]

This paper presents a 1:20,000 scale Geoarchaeological map of the Cornia river coastal plain in southern Tuscany. The Geoarchaeological map integrates a comprehensive dataset of geomorphological and archaeological features. The spatial relationships between landforms and archaeological records show that the settlement pattern from the VII century BC to the V century AD was mostly influenced by the presence of several depositional landforms which formed before the period under consideration. Integrating the outputs of geomorphological and topographical analyses with archaeological databases is also helpful for land planning, especially in areas where present-day anthropic exploitation needs predictive and valid tools to assess the archaeological hazard. [ABSTRACT FROM AUTHOR]

Coastal Peru, one of the driest deserts in the world, is a key region to investigate the connection between climate processes and Earth surface responses. However, the trends in space and time of the landscape effects of El Niño events throughout the last millennium are hard to outline. A deeper understanding of geological and archaeological data in pre-Hispanic time can help to shed light on some critical questions regarding the relationship between such a coupled atmosphere–ocean phenomenon and landscape modifications. The bibliographic sources required for this purpose are scattered throughout various disciplines, ranging from physical to human sciences, and thus comprehensive databases were used to identify and screen relevant studies. The performed examination of these documents allowed us to assess strengths and weaknesses of literature hypotheses and motivate additional studies on targeted research objectives. [ABSTRACT FROM AUTHOR]

The understanding of the relationships between abiotic components and these with the natural system, especially in coastal areas and densely occupied areas, such as urban agglomerations, has been important to support policies of conservation, preservation, and sustainable regional development. In this sense, the aim of this study was to carry out an assessment on a regional scale of the geodiversity of the Urban Agglomeration of the South (AUSul), the coast of Rio Grande do Sul, and its constituent municipalities, through a geodiversity index and the occurrence and distribution of its elements in the region. To construct the index, the abiotic elements considered most relevant for the region’s characteristics and the availability of data approximately compatible with the 1:250,000 scale was qualitatively defined. Subsequently, they were treated with methods of map algebra, resulting in the maps of the sub-indices related to geology, topography and geomorphology, hydrography and soils per municipality, and the geodiversity index of each municipality and the region. The results indicate the municipalities located on the Sul-Rio-Grandense Plateau and at the interface with the Coastal Plain with the highest indexes, being influenced by the greatest diversity of geological units, relief types, altimetric variations, and hydrographic features. Despite the significant occurrence of large wetland areas in the Coastal Plain municipalities, their indices were the lowest. The study proved to be useful for the understanding of the geodiversity of the AUSul, pointing out areas for studies at larger scales and macro-zoning, in addition to the need for complementation with methods that incorporate subjective characteristics of geodiversity.

Clayey aquitards are widespread in the coastal plain and they are capable to preserve paleo-saltwater. Its salinity distribution and transport process play an important role on the evolution of aquifer groundwater, yet they have attracted little attention. In this paper, undisturbed clayey samples in seven boreholes along the Jiangsu coastal plain were collected and porewater was extracted by squeezing. Based on the natural tracers Cl- and Br- profiles and numerical simulation, porewater salinity characterization and transport mechanism were analyzed. The results showed that two trends of porewater Cl- variations are observed: one is that Cl- peak value is near surface and decreases with depth; the other one is that the Cl- peak value is at depth of 25 m and decreases towards both ends. Porewater has a Cl- range of 486.2-38 036.7 mg/L and Cl/Br of 72-360(average: 241). The relations between Cl- and Cl/Br ratios and the profile signature indicate that saline porewater is of marine origin, and from the Holocene transgression seawater. Subsequently, they were diluted by freshwater. Aquitard porewater 1-D transport model suggests that the transgression and regression events are dominant for the salinity evolution. Holocene seawater is still trapped in the sediment whereas Pleistocene seawater has been flushed out. In aquitard, diffusion is dominant for solute transport with the vertical velocity of 0.43-15.8 mm/yr and influenced by advection in higher permeability sand layers. The redistribution of paleo-saltwater, in particular, in the condition of groundwater over-extraction, would be the important saline source for aquifer groundwater.

Morphological changes attributed to anthropogenic activities is one of the fundamental drivers of local, regional and global environmental changes. Studies of morphology has become vital in enhancing the understanding and monitoring of environmental changes. On this aspect, the present study details the spatio-temporal status of the alluvial and coastal plains of the Kandaleru river of Nellore district using Landsat, LISS III and Sentinel 2A satellite images for the years 1973, 1988 and 2020. The study utilized Remote Sensing (RS), Geographical Information System (GIS) and Digital Shoreline Analysis System (DSAS) capabilities to identify the morphological changes and their impacts. Interpretation of morphological features from temporal satellite images were carried out using Maximum Likelihood Classifier (MLC) technique of remote sensing and the impacts were studied using spatial analyst tools of ArcGIS and river bank dynamics was assessed and quantified using DSAS model. The study indicated a decrease in the spatial extent of both alluvial and coastal plains of the Kandaleru river during the study period. The alluvial plain decreased from 106.98 km2 in 1973 to 64.34 km2 in 2020 predominantly due to growth of aquaponds and other anthropogenic human interventions such as the growth of commercial and habitation areas. The coastal plain decreased by 13% during the study period due to the development of port and its related activities. The study revealed the regional stress of morphological features around the river which is one of the vital data to allude restrictions in such fertile landforms.

In this study, we explored the association between land use and fish species richness on 52 coastal lagoons in Southeast and South Brazil. We measured the proportion of agriculture and urbanization around lagoons over 26 years and used the coefficient of variation (CV) as a surrogate of the temporal land cover variability. We compiled species occurrences from primary data, from the literature and from museum records, and assigned each recorded species to different habitat use groups: benthic/bottom or water column, and littoral or limnetic zones. In the Southeast, where most lagoons are subject to marine influence, richness was negatively associated to agriculture and positively associated to urbanization. In the South, where freshwater lagoons predominate, richness was negatively associated to urbanization and positively associated to agriculture. The results suggest that fish communities from freshwater coastal lagoons are more sensitive to land use than brackish lagoons. Differently from brackish lagoons, that are colonized by both freshwater and marine species, freshwater lagoons rely on neighboring lagoons as species donors. However, this apparent resilience of the brackish lagoons must be regarded with caution, since the increase in marine connections due to artificial sandbar openings may impair freshwater species with time. [ABSTRACT FROM AUTHOR]

Numerous wetland depressions occur across the U.S. Atlantic Coastal Plain, a region of complex physiography spanning a landward-to-seaward elevation gradient. Coastal Plain depressional wetlands are noted for supporting a diversity of plant communities that provide important faunal habitats. Because these "isolated" wetlands are vulnerable to degradation and loss on private lands, protected and managed public lands have become important refugia for their conservation. A practical system of vegetation types and vegetation-dynamics models can aid in developing management or restoration strategies for these conserved wetlands. The concept of hydrogeologic landscapes provides a useful model framework because landform, soils, and topographic position can influence not only depression form and hydropattern, but also ecological drivers of vegetation change such as drought, fire, and land-use. In the Lower Coastal Plain of South Carolina, USA, a hydrogeologic-landscapes approach was used to examine relationships between wetland vegetation and depression attributes such as size, soil type, and hydroperiod. The Lower Coastal Plain data were also combined with a similar Upper Coastal Plain study to provide a synthetic analysis of region-wide patterns. These studies identified a consistent set of wetland vegetation types that differed in landscape-associated depression attributes. Wetland types also differed in occurrence across sub-regions, owing in part to contrasting histories of land-use and wetland disturbance. The findings were used to develop conceptual state-change models that link wetland vegetation to depression hydropatterns and other ecological drivers in different landscape settings. [ABSTRACT FROM AUTHOR]

Pecan (Carya illinoinensis) orchards in Georgia and throughout the southeastern United States are commonly established from land that had previously been used for row cropping systems. Soil quality is characteristically low in the loamy-sand, low pH soils of the southeastern Coastal Plain. Changes in land use are known to exhibit different effects on soil quality; however, no studies specifically address soil enhancement from converting row crop land to pecan orchards in this region. Sampling was conducted in eight counties throughout the coastal plain of South Georgia in 2020 and 2021. The objectives of this study were to analyze and compare soil quality indicators of pecan orchards of varying ages and adjacent row crop fields. Soil quality indicators analyzed include soil organic matter (SOM), active carbon or permanganate oxidizable carbon (POXC), aggregate stability, cation exchange capacity (CEC), bulk density, porosity, Solvita CO2-Burst, SLAN (Solvita labile-amino nitrogen), pH, and total N. Results from this study demonstrate that pecan orchards under commercial management had higher soil quality compared with row crop fields based on the indicators measured. Active carbon and Solvita CO2-Burst measurements suggest that pecan orchards exhibited significantly higher rates of microbial activity and soil respiration. Indicators of soil microbial activity such as active carbon and Solvita CO2-Burst were strongly correlated with SOM, which explained much of the variation observed in these measurements of soil microbial activity. Selected soil quality indicators also provide evidence that the soil quality of commercial pecan orchards in this region improves with orchard age. [ABSTRACT FROM AUTHOR]

Complex freshwater–saltwater exchanges characterize most Holocene groundwater aquifers in low-lying coastal plains around the world, particularly in mechanically drained territories. This is due to the combination of several factors that control groundwater dynamics, including the high variability of the Holocene coastal deposits that host the shallow aquifers and the water management practices. The relationships between the stratal architecture of sedimentary deposits and the vertical changes in the salinity of the phreatic aquifer are poorly studied although they represent an issue of primary importance for a sustainable use of water resources and for agriculture. This research work is focused on the influence of sedimentary constraints, i.e., stratigraphic discontinuities and related changes in permeability in shaping salinity stratification into the unconfined aquifer at the southern margin of the Venice lagoon (Italy). Nine sites have been investigated by collecting sediment cores for facies analysis and monitoring water electrical conductivity in piezometric wells. The results show that buried channelized sandy deposits can enhance salinity mitigation of the phreatic aquifer in conjunction with precipitations and sufficient freshwater supply from nearby rivers and irrigation channels. Our analyses also reveal that the differences in stratigraphic architecture of the upper 10 m of the subsoil determine different fresh–saltwater dynamics of the phreatic aquifer. In particular, three possible behaviors can occur: (i) where the subsurface is characterized by the presence of a thick, up to 5 m, paleochannel, a freshwater lens is always present in the most surficial part of the phreatic aquifer; (ii) where the subsurface is composed by fine-grained sediments of marsh and lagoon paleo-environment, the phreatic aquifer tends to be salt-contaminated over its entire thickness; (iii) where the subsurface contains thin, up to 2–3 m, paleochannel deposits, the fresh–saltwater dynamics of the most surficial part of the phreatic aquifer varies more during the year, as a result of seasonal precipitation trend. The provided characterization of saltwater dynamics represents the basis for planning mitigation measures to improve the farmland productivity of the Venetian coastal plains. [ABSTRACT FROM AUTHOR]

The paper considers geological structure of the coastal region of the South Caspian, including paleontological and magnetostratigraphic dating of the Neogene–Quaternary deposits. Western and eastern segments of the region between the South Caspian Basin and the Alborz Ridge developed differently in the Late Cenozoic. In the west, marine sediments did not penetrate beyond the coastal plain into the neighboring lowered part of the Alborz Ridge during the Pliocene–Quaternary. This indicates the stability of the marine basin boundary or its expansion due to the abrasion of the Alborz slopes. In the east, a piedmont step emerged, bounded by thrust faults. The marine deposition at the piedmont step occurred in the Miocene. At the end of the Miocene, the marine sediments were folded and eroded. The Akchagylian (Piacenzian–Gelasian) marine sediments accumulated at the northern edge of the piedmont step. The Khazar fault raised these sediments up to 120–150 m and isolated the piedmont step. Thus, the expansion of the Alborz mountain building and the reduction of the South Caspian Basin occurred in the eastern part of the coastal area from the Late Miocene. The differences between the western and eastern segments of the coastal area are related to the development of the South Caspian Basin. Until the Late Miocene, it remained a residual trough of the Paratethys. During the Pliocene–Quaternary, the eastern part was filled with sediments up to 6 km thick and retained the features of a thinned continental crust 30–37 km thick with sedimentary cover up to 16 km thick. The western part of the basin was filled with sediments about 10 km thick and acquired the features of suboceanic crust with the Mohorovichich surface at a depth of 28–30 km with a thickness of the sedimentary cover exceeding 20 km. [ABSTRACT FROM AUTHOR]

Pecan (Carya illinoinensis) orchards in Georgia and throughout the southeastern United States are commonly established from land that had previously been used for row cropping systems. Soil quality is characteristically low in the loamy-sand, low pH soils of the southeastern Coastal Plain. Changes in land use are known to exhibit different effects on soil quality; however, no studies specifically address soil enhancement from converting row crop land to pecan orchards in this region. Sampling was conducted in eight counties throughout the coastal plain of South Georgia in 2020 and 2021. The objectives of this study were to analyze and compare soil quality indicators of pecan orchards of varying ages and adjacent row crop fields. Soil quality indicators analyzed include soil organic matter (SOM), active carbon or permanganate oxidizable carbon (POXC), aggregate stability, cation exchange capacity (CEC), bulk density, porosity, Solvita CO2-Burst, SLAN (Solvita labile-amino nitrogen), pH, and total N. Results from this study demonstrate that pecan orchards under commercial management had higher soil quality compared with row crop fields based on the indicators measured. Active carbon and Solvita CO2-Burst measurements suggest that pecan orchards exhibited significantly higher rates of microbial activity and soil respiration. Indicators of soil microbial activity such as active carbon and Solvita CO2-Burst were strongly correlated with SOM, which explained much of the variation observed in these measurements of soil microbial activity. Selected soil quality indicators also provide evidence that the soil quality of commercial pecan orchards in this region improves with orchard age.

Soil salinization hinders sustainable agricultural development in coastal regions. Developing a multi-layer soil salinity inversion model and accurately predicting water demand for salt regulation are essential for improving soil salinity management. Wudi County in Shandong Province was selected as the research area, with 79 sampling sites chosen. Soil salinity was measured at the surface (0–20 cm), middle (20–40 cm), and bottom (40–60 cm) layers. Vegetation and salinity indices were extracted from Landsat 8 remote sensing imagery to estimate surface soil salinity. A correlation-based inversion method was developed to obtain multi-layer soil salinity data by leveraging the strong correlation between adjacent soil layers. The water requirement for salt regulation was optimized and predicted by integrating the results from multi-layer soil salinity estimation with Groundwater Management System (GMS) software. The results indicated that the surface layer soil salinity inversion model performed well, with an R 2 > 0.75 and an RMSE < 0.43 g/kg for both the training and validation sets. Additionally, the prediction accuracy of the correlation-based inversion method exceeded that of the direct modeling approach, with the middle and bottom layer soil salinity models achieving an R 2 > 0.6 and an RMSE < 1 g/kg. Soil salinization in the study area was more severe in the northeast than in the southwest, with both measured and estimated data showing similar spatial distributions. Over the past decade, the overall trend of soil salinization has shown a general decline with localized intensification. The salt distribution patterns in saline soil profiles were predominantly homogeneous and bottom-accumulated. The projected water demand for salt regulation calculated from the estimated data was slightly lower than the actual measurements, yet their spatial distribution was nearly identical. This study provides a scientific foundation for the dynamic monitoring and precise management of soil salinity in coastal regions. [Display omitted] • Vegetation and salinity indices can reflect multi-layer soil salinity information. • Developed predictive models for soil salinity across three soil layers in coastal regions. • Distribution of soil salinity profiles is primarily characterized by homogeneity and bottom accumulation. • The trend of soil salinization experienced a general decline with localized intensification. • Integrating the salinity prediction model enables dynamic monitoring of water requirements for salt regulation. [ABSTRACT FROM AUTHOR]

Stream restoration projects undertaken as compensatory mitigation pursuant to Sect. 404 of the U.S. Clean Water Act must be evaluated using ecological performance standards that are objective and verifiable and based on the best available science that can be measured or assessed in a practicable manner. While performance standards for physical stream conditions are common, evaluating biological conditions following stream restoration activities has proven more problematic. We developed a macroinvertebrate multimetric index for headwater streams in three Southeastern Plains subecoregions (65 g, 65 h, and 65 l) of Georgia using 76 sites sampled in 2019. An abiotic disturbance gradient based on principal components analysis of instream habitat, physicochemical, and land use variables was employed to assign condition classes (good, fair, poor) among sites within each subecoregion. We identified genus-level macroinvertebrate richness and proportional richness of traits-based metrics (habit and functional feeding groups) that demonstrated high discriminatory power between good and poor abiotic conditions and response to individual stressors. Subecoregion-specific metrics were then standardized and aggregated to develop the final index and biological reference curves. These biological reference curves represent a continuum of relevant regional conditions against which a stream enhancement or restoration project may be assessed relative to other streams throughout the region and allow for the award of mitigation credit, if applicable, to be based directly on the relative improvement of biological conditions. These biological performance standards will supplement other performance standards (hydrologic and geomorphic measures) necessary to evaluate the effectiveness of stream restoration projects in the study area. [ABSTRACT FROM AUTHOR]

The geographic landscape is a recurrent unit of analysis in vulnerability studies. Single descriptions are often used to show the elements exposed in these landscapes. However, the concept requires specifying the components of the landscape and its functioning as a unit. Thus, the purpose of this research was to use the analysis of Nature's Contributions to People (NCP) to describe the global contribution of landscape elements to human activities, prioritizing the units in which the effects of climate change may imply greater impacts on the human population. For this, we analyzed six categories of nature's contributions applied to the landscape units in a fragment of the Mexican Pacific coast. The units with mangrove cover had the highest nature contributions. It is expected that the application of this approach in the exposure component of vulnerability studies will allow a better understanding of the non-return relationship and the search for adaptive nature-based solutions. [ABSTRACT FROM AUTHOR]

We present the results of the geomorphological mapping of a region of the Dhofar (Sultanate of Oman) including two contrasting physiographic units sharing a common drainage system into the Arabian Sea: the Jebel Qara limestone massif and the coastal plain of Salalah. Neogene to Quaternary tectonic activity controlled the formation of an extensive system of faults and caused the uplift of the Jebel Qara, forming structural escarpments. The massif underwent karstification and subsequent linear erosion. Today the Jebel is cut by a dendritic net of dry valleys, occasionally dammed by calcareous tufa dams. The transition between the southern escarpment of the Jebel and the plain below displays flat alluvial fans, bordered by a strip of beachrock, coastal dunes, and coastal lagoons, located in correspondence to estuaries. Dramatic soil erosion is evident, linked to intense human-triggered zoogeomorphological processes started in the Mid-Late Holocene after the introduction of pastoral land-use.

The understanding of the relationships between abiotic components and these with the natural system, especially in coastal areas and densely occupied areas, such as urban agglomerations, has been important to support policies of conservation, preservation, and sustainable regional development. In this sense, the aim of this study was to carry out an assessment on a regional scale of the geodiversity of the Urban Agglomeration of the South (AUSul), the coast of Rio Grande do Sul, and its constituent municipalities, through a geodiversity index and the occurrence and distribution of its elements in the region. To construct the index, the abiotic elements considered most relevant for the region’s characteristics and the availability of data approximately compatible with the 1:250,000 scale was qualitatively defined. Subsequently, they were treated with methods of map algebra, resulting in the maps of the sub-indices related to geology, topography and geomorphology, hydrography and soils per municipality, and the geodiversity index of each municipality and the region. The results indicate the municipalities located on the Sul-Rio-Grandense Plateau and at the interface with the Coastal Plain with the highest indexes, being influenced by the greatest diversity of geological units, relief types, altimetric variations, and hydrographic features. Despite the significant occurrence of large wetland areas in the Coastal Plain municipalities, their indices were the lowest. The study proved to be useful for the understanding of the geodiversity of the AUSul, pointing out areas for studies at larger scales and macro-zoning, in addition to the need for complementation with methods that incorporate subjective characteristics of geodiversity. [ABSTRACT FROM AUTHOR]

Morphological changes attributed to anthropogenic activities is one of the fundamental drivers of local, regional and global environmental changes. Studies of morphology has become vital in enhancing the understanding and monitoring of environmental changes. On this aspect, the present study details the spatio-temporal status of the alluvial and coastal plains of the Kandaleru river of Nellore district using Landsat, LISS III and Sentinel 2A satellite images for the years 1973, 1988 and 2020. The study utilized Remote Sensing (RS), Geographical Information System (GIS) and Digital Shoreline Analysis System (DSAS) capabilities to identify the morphological changes and their impacts. Interpretation of morphological features from temporal satellite images were carried out using Maximum Likelihood Classifier (MLC) technique of remote sensing and the impacts were studied using spatial analyst tools of ArcGIS and river bank dynamics was assessed and quantified using DSAS model. The study indicated a decrease in the spatial extent of both alluvial and coastal plains of the Kandaleru river during the study period. The alluvial plain decreased from 106.98 km2 in 1973 to 64.34 km2 in 2020 predominantly due to growth of aquaponds and other anthropogenic human interventions such as the growth of commercial and habitation areas. The coastal plain decreased by 13% during the study period due to the development of port and its related activities. The study revealed the regional stress of morphological features around the river which is one of the vital data to allude restrictions in such fertile landforms. [ABSTRACT FROM AUTHOR]

Coarse woody debris (CWD) addition is a restoration technique that has been used to reduce effects of landscape disturbance on instream habitat. However, efficacy of this technique for improving ecosystem condition is not well established, in part because monitoring designed to evaluate long-term efficacy is rare. We assessed the effectiveness of CWD additions in disturbed Coastal Plain streams at Fort Benning Military Installation, Georgia, USA, 14 y after initial restoration. In October 2003, 4 disturbed streams received CWD additions (restored streams), and 4 streams were left as unrestored controls. Pre-restoration (2001–2003) and post-restoration (2003–2006) monitoring of nutrient uptake, stream metabolism, and water-quality variables revealed 1) minimal change in water-quality variables, 2) increased stream metabolism and nutrient-uptake rates immediately following restoration, and 3) decreased metabolism and uptake over the remainder of the 3-y post-restoration period. We returned to these streams in 2017 and 2018, measured the same variables, and found minimal long-term effects of restoration on water quality, nutrient uptake, and whole-stream metabolism indicators; however, streamwater pH decreased in all streams 14 y after restoration, and there was a weak treatment × period interaction, indicating that CWD additions may decrease pH in the long term. Further, we found few relationships between watershed disturbance and water-quality variables and ecosystem function metrics, although some relationships were apparent during certain seasons and years. Our study is one of the few that have assessed the long-term effects of CWD additions, or any other stream-restoration technique, on ecosystem function. These long-term assessments may be necessary to determine if restorations are a good use of limited resources. [ABSTRACT FROM AUTHOR]

Effective management of wildlife populations benefits from an understanding of the long-term vulnerability of species to anthropogenic stressors. Exposure to potential habitat change is one measure of vulnerability that wildlife managers often use to assess and prioritize individual species or groups of species for resource allocation or direct management actions. We used species distribution models for 15 species occurring in the coastal plain ecoregion of Georgia to estimate the current amount and distribution of potential habitat and then predict exposure to changes in habitat due to inundation from sea level rise (using the Sea Level Affecting Marshes model) and urban growth (using the Slope Land-use Excluded Urban Topology Hillshade Growth model) for four future time points. Our results predict that all focal species were likely to experience some exposure to habitat change from either sea level rise or urbanization, but few species will experience high exposure to change from both stressors. Species that use salt marsh or beach habitats had the highest predicted exposure from sea level rise (25-69%), while species that use more inland habitats had the highest predicted exposure to urban growth (10-20%). Our models are a resource for managers considering tradeoffs between prioritization schemes under two future stressors. Results suggest that managers may need to prioritize species (or their habitats) based on the predicted magnitude of habitat loss, while also contextualizing prioritization with respect to the current amount of available protected habitat and species global vulnerability. [ABSTRACT FROM AUTHOR]

The states of Georgia and South Carolina emitted ∼100 million tons (Mt) of CO2 in 2019 from point sources. Integration and interpretation of subsurface data enabled identification of a previously unrecognized, regionally extensive, and thick (up to 450 m) sedimentary sequence—the Red beds of Hazlehurst (RbH)—as a potential saline reservoir for CO2 storage in the southeastern United States. Based on the renewed stratigraphic framework and structural interpretation of the RbH interval, we analyzed detailed well logs and the depositional environments to provide reconnaissance-level regional scale estimations of the storage resource. The volumetric results suggest the effective storage area (∼85,000 km2) has a maximum resource potential for 390 gigatons (Gt) of anthropogenic CO2. Petrophysical measurements suggest the permeability of RbH ranges from 0.001 to 48 mD, and the porosity ranges from 11.1 to 18.4%. Residual/capillary trapping and solubility trapping act as the main trapping mechanisms for long term storage and prevent vertical migration of CO2 into the shallow freshwater aquifers. Due to the heterogeneity observed in geophysical logs and the scarcity of well penetrations, future data collection is needed to characterize the storage aquifer and confining aquitards of a site-specific system at this stage.

Coastal Peru, one of the driest deserts in the world, is a key region to investigate the connection between climate processes and Earth surface responses. However, the trends in space and time of the landscape effects of El Niño events throughout the last millennium are hard to outline. A deeper understanding of geological and archaeological data in pre-Hispanic time can help to shed light on some critical questions regarding the relationship between such a coupled atmosphere–ocean phenomenon and landscape modifications. The bibliographic sources required for this purpose are scattered throughout various disciplines, ranging from physical to human sciences, and thus comprehensive databases were used to identify and screen relevant studies. The performed examination of these documents allowed us to assess strengths and weaknesses of literature hypotheses and motivate additional studies on targeted research objectives.

The town of Rue was one of the most important coastal harbours of Picardy, Northern France, from the beginning of the 12th century to the end of the 15th century CE. Document sources and ancient maps confirm the existence of this vibrant harbour. Until now, however, no palaeoenvironmental studies have attempted to reconstruct the configuration of the region's coastline during medieval times. Here we employ a geoarchaeological approach to reconstruct the Mid-to Late Holocene shoreline and landscape changes in the Rue area. Our approach includes a geophysical survey (Electric Resistivity Tomography method) and a series of eight sediment cores that reveal the region's chronostratigraphy. Document sources were also used to shed light on the landscape configuration during the Late Middle Ages (ca. 1300 CE). Our coring results, based on sedimentological analyses, are combined with 2D geophysical profiles down to 21.50 m. This reveals, firstly, that a calm marine environment prevailed at the beginning of the 4th millennium BCE, particularly in depressions bordered by Pleistocene coastal spits (foraines). Secondly, from ca. 3500 BCE to ca. 1000 BCE, coastal swamps predominated. Then, thirdly, at around 1000–1250 CE, an estuarine depositional environment prevailed, prior to a final period of land reclamation of the former Maye Estuary from the 13th century CE onwards. These results agree well with recent work on sea level changes along the Atlantic and English Channel coasts of France, where continuous post-glacial sea level rise has been observed. Our study also proposes a location of the medieval harbour of Rue to the west of the town at the upstream boundary of the upper part of the Maye Estuary, near ' Le Moulin de Saint-Jean' , although archaeological evidence of the exact site of this tidal harbour is still lacking. [ABSTRACT FROM AUTHOR]

Land-use classification is fundamental for environmental and water resource evaluation in coastal plain areas. However, comprehensive remote sensing image-based land-use analysis is challenged by the lack of massive remote sensing images and the massive computing power of large-scale server systems. In this paper, the spatial-temporal land-use change characteristics of the Hangzhou Bay area coastal plain are investigated on the Google Earth Engine platform. The proposed model uses a random forest algorithm to assist the land-use classification. The dataset is selected from the year 2009 to 2020 and classified with an average classification accuracy of 89% and Kappa coefficient of 88%. The results show that the land use in the selected region is affected by urbanization, the balance of cultivated land occupation and compensation, construction of economic development zone, and other activities. The investigation also shows that in the past 12 years, land use has changed rapidly, and each land-use type maintains the dynamic balance of occupation and compensation. Although the overall land-use distribution is stable, the information entropy fluctuates at a high level, with an average value of 1.15, and the multi-year average value of equilibrium is as high as 0.83. The driving force of land-use change is analyzed and accounted as demographics and human population dynamics, social-economic development, urbanization, and coupling effects of the above-mentioned factors. [ABSTRACT FROM AUTHOR]

Isolated wetlands embedded within longleaf pine savannas support a high proportion of regional biodiversity including many amphibian species. Today, remnant isolated wetlands are often overgrown and hydrologically altered due to fire exclusion or incompatible, cool season fire regimes. In the absence of warm season fires when wetlands are dry, shrubs and trees succeed herbaceous plants, which alters wetland productivity via effects on light and detritus quality. We used a factorial aquatic mesocosm study to test the effects of altered detritus and shade on the growth, development, and survival of tadpoles of two priority amphibian species: gopher frogs (Rana capito) and ornate chorus frogs (Pseudacris ornata). Gopher frog survival was higher among maidencane, sedge, and pine treatments compared to oak and sweetgum treatments. While gopher frog larval periods were lowest in the sedge treatment, there was a nominal general effect of litter type on gopher frog larval periods, growth rates, and mass at metamorphosis. Shading had a nominal and inconsistent effect on gopher frog growth rates, but did extend larval periods in all litter treatments, decreased survival in all litter treatments except oak, and decreased mass at metamorphosis in all litter treatments except pine and sweetgum. Ornate chorus frog survival was minimally affected by shading and litter treatments, but growth rates and mass at metamorphosis were highest in maidencane and sedge treatments, and larval periods were extended with shading in all litter treatments. Shading also decreased growth rates in maidencane and sedge litters and decreased mass at metamorphosis in pine and sweetgum litters. Our results demonstrate that succession of isolated wetlands can reduce tadpole performance for two priority species both through changes in leaf litter and shading, though the effect on survival, larval growth, larval period, and size at metamorphosis can differ between species. These results support management recommendations to restore and maintain open canopy, grassy conditions in isolated wetlands for conservation of priority amphibian species. [ABSTRACT FROM AUTHOR]

Abstract Isolated wetlands embedded within longleaf pine savannas support a high proportion of regional biodiversity including many amphibian species. Today, remnant isolated wetlands are often overgrown and hydrologically altered due to fire exclusion or incompatible, cool season fire regimes. In the absence of warm season fires when wetlands are dry, shrubs and trees succeed herbaceous plants, which alters wetland productivity via effects on light and detritus quality. We used a factorial aquatic mesocosm study to test the effects of altered detritus and shade on the growth, development, and survival of tadpoles of two priority amphibian species: gopher frogs (Rana capito) and ornate chorus frogs (Pseudacris ornata). Gopher frog survival was higher among maidencane, sedge, and pine treatments compared to oak and sweetgum treatments. While gopher frog larval periods were lowest in the sedge treatment, there was a nominal general effect of litter type on gopher frog larval periods, growth rates, and mass at metamorphosis. Shading had a nominal and inconsistent effect on gopher frog growth rates, but did extend larval periods in all litter treatments, decreased survival in all litter treatments except oak, and decreased mass at metamorphosis in all litter treatments except pine and sweetgum. Ornate chorus frog survival was minimally affected by shading and litter treatments, but growth rates and mass at metamorphosis were highest in maidencane and sedge treatments, and larval periods were extended with shading in all litter treatments. Shading also decreased growth rates in maidencane and sedge litters and decreased mass at metamorphosis in pine and sweetgum litters. Our results demonstrate that succession of isolated wetlands can reduce tadpole performance for two priority species both through changes in leaf litter and shading, though the effect on survival, larval growth, larval period, and size at metamorphosis can differ between species. These results support management recommendations to restore and maintain open canopy, grassy conditions in isolated wetlands for conservation of priority amphibian species.