Lower Coastal Plain Research Articles

The effects of land subsidence and its mitigating measures on shallow groundwater salinization in the low-lying coastal plain of East Japan

Land subsidence in low-lying coastal regions results from geological and human factors, causing inundation during high tides. Mitigation measures, like pumping stations and ditch systems, aim to address this challenge. However, their impact on groundwater salinity near tidal rivers is understudied. Using a coupled surface-subsurface model, we investigate this issue in the lower Nabaki River region, Shirako Town, Japan. The simulation reveals adverse effects of pumping stations that induce intrusion of saline water from the tidal river into surrounding groundwater. While they are designed to prevent floods, these stations and ditches may inadvertently raise groundwater vulnerability to saltwater contamination. Despite 2D model limitations, it offers valuable insights into coastal groundwater dynamics and salinization. This study provides important information for policymakers and land managers to better understand the consequences of flood mitigation strategies on groundwater quality in vulnerable coastal areas.

Late Albian-Cenomanian paleoenvironmental and paleoclimatic reconstructions in northeastern Gondwana: Palynological perceptions

The late Albian-Cenomanian (100.5–93.9 Ma) is considered a greenhouse world without permanent ice caps and with high eustatic sea levels. The high sea-level led to the flooding of low-lying coastal plains and the formation of extensive shallow shelf seas. Depositional conditions and ecosystems at these marginal and shallow shelf settings were affected by changes in environmental conditions, such as climate and vegetational ecosystems in surrounding regions. This study conducts palynomorph and palynofacies and lithofacies analysis of fifty-nine cutting samples from the North Qarun-1x well in the Gindi Basin (North Western Desert, Egypt) to assess the evolution of depositional and paleoenvironmental conditions as well as paleo-vegetation pattern in response to changes in climate and sea level. The sediment succession comprises the upper Albian to Cenomanian upper Kharita and Bahariya formations and Abu Roash G Member. Biostratigraphic analysis of palynomorph composition led to define seven interval zones of upper Albian-Cenomanian. At this time, Egypt was inundated by the southern margin of the Tethys Ocean, which led to the deposition of thick siliciclastic and carbonate facies in a marginal marine depositional environment. Statistical cluster analysis of particulate organic matter (POM) allowed three palynofacies assemblages (PFA-1 to PFA-3) to be recognized, indicating oscillating depositional conditions that shifted between fluvio-deltaic to marginal shallow marine, proximal, and distal inner neritic shelf environments. PFA-1 comprises the highest proportions of total phytoclasts, indicating fluvio-deltaic to marginal shallow marine conditions. PFA-2 is dominated by moderate abundances of AOM and phytoclasts, characterizing a proximal inner neritic shelf environment. PFA-3 consists of a slightly higher concentration of AOM compared to phytoclasts, indicating a distal inner neritic shelf environment with diminished terrestrial input and increased abundances of marine microplankton. Organic palynomorphs are abundant in mid-Cretaceous strata of northern Egypt. Abundant records of humidity indicators, mainly fern spores, along with other gymnosperms (mainly Taxodiaceae and Araucariaceae) compared to low aridity indicators of gnetalean Elaterates and Ephedroids along with non-gnetalean Classopollis suggest predominantly warm and humid conditions. Two intervals in the lower part of the Bahariya Formation and in the middle part of the Abu Roash G Member showed moderate to high abundances of aridity indicators and thus, warm arid to semi-arid climate events during the early and late Cenomanian.

Assessment of flood mitigation strategy based on integrated approach of remote sensing and coastal vulnerability geospatial modeling at the coastal plain of Suriname

Suriname is the smallest South American nation with a low-lying coastal plain that is vulnerable to inundation from the Atlantic Ocean and inland rivers, as well as pluvial flooding primarily due to rainfall. Paramaribo, the capital of Suriname, has the highest population density, and its demographics extend into the surrounding districts of Wanica and Commewijne. Suriname has experienced flood disasters almost annually, which has exacerbated in recent years, posing a significant socioeconomic challenge. The country must balance the need for flood disaster adaptation and climate resilience with the potential impact on its resources and well-being of settlement areas. Policymakers and other stakeholders are working to address environmental impacts on the coast, but there is still a need for a comprehensive approach to monitor and manage flood impacts. This research has three objectives. The first is to analyze flood frequency events from 2021 to 2023 using multi-temporal satellite image processing from Sentinel-1 SAR (Synthetic Aperture Radar). The second is to generate a Coastal Flood Vulnerability Index (CFVI) for floods using a geospatial multi-criteria analysis approach based on exposure, sensitivity, and adaptive capacity components. The third objective is to assess the mitigation strategy for floods in settlement areas based on an integrated analysis of CFVI and stakeholder perception. The research methodology uses a multi-criteria analysis regarding settlement areas and ranking each component by expert opinion in an equation derived from Intergovernmental Panel on Climate Change (IPCC) assessment report at district level. The CFVI indices rely on secondary data acquisition from national and global datasets or referenced works. Interviews were conducted to better understand the stakeholder’s perspectives that are at a strategic or governing level, and to evaluate the existence of flood early-warning and other adaptation capabilities. A flood mitigation strategy is then suggested for the most vulnerable district by CFVI score.

A maximum entropy approach to defining geographic bounds on growth and yield model usage

Growth and yield models are essential tools in modern forestry, especially for intensively managed loblolly pine plantations in the southeastern United States. While model developers often have a good idea of where these models should be used with respect to geographic location, determining geographic bounds for model usage can be daunting. Such bounds provide suitable areas where model predictions are likely to behave as expected or identify areas where models may do a poor job of characterizing the growth of a resource. In this research, we adapted a niche model methodology, commonly used to identify suitable spots for species occurrence (maximum entropy), to identify areas for using growth and yield models built from plots established in the Lower Coastal Plain and Piedmont/Upper Coastal Plain in the southeastern United States. The results from this analysis identify areas with similar climatic envelopes and soil properties to the areas where data was collected to fit these growth and yield models. These areas show notable overlap with the areas prescribed for use by the evaluated growth and yield models and support practitioners use of these models throughout these regions. Furthermore, this methodology can be applied to different forest models built using large regional extents as long as climatic and soil values are available for each site.

The role of phreatomagmatism in the formation of complex monogenetic volcanic systems in a low-lying coastal plain

Monogenetic volcanoes are characterised worldwide by a single eruptive phase that is short-lived, with small eruptive volumes that produce a wide range and complexity of landforms. Investigating the evolution in eruptive styles through the active history of a volcano is key to understanding the role of phreatomagmatism in the formation of these complex monogenetic systems. The classification of the complexity of a monogenetic volcanic centre is of great significance to understanding both past volcanoes and the hazards of future volcanoes. Complexity can be defined by the number of volcanic structures created, the presence of multiple types of eruptions, and the number of conduits involved. In this paper we reconstruct the volcanic history of the Waitomokia Volcanic Complex, located in the southern lowlands of the active monogenetic Auckland Volcanic Field (AVF), New Zealand. Activity began with deposition of an initial tuff ring, followed by vent migration and establishment of a maar with a surrounding tuff ring. Four smaller tuff rings developed on the north and northeastern rim of the maar. This was followed by the noteworthy deposition of complex intercalated transitional deposits from at least two tuff rings and magmatic deposits from a scoria cone. Three scoria cones were then built within the maar, followed by minor effusion of short lava flows. Waitomokia highlights the prospect of having a complex system with ten or more landforms being created in different areas active at the same time, with associated eruptive styles and mechanisms. The possibility of a complex eruption, where several styles may occur simultaneously from distinct vents, should be considered in hazard assessment and crisis management plans.

Assessing Mid-rotation Loblolly Pine and Competing Vegetation Responses to Post-thin Fertilization and Herbicide Application in the Southeastern United States

Abstract Mid-rotation silvicultural treatments (MRT) are commonly applied to loblolly pine (Pinus taeda L.) plantations in the southeastern United States to improve pine productivity. Competing vegetation is often present in operational plantations and limits site resource availability. The benefits of MRT for pine productivity are well known, but competing vegetation growth has not been extensively studied. Pine and competing vegetation growth within two regions of the southeastern United States was monitored for 8 years following a one-time post-thin application of either fertilization (224 kg ha-1 of nitrogen plus 28 kg ha-1 phosphorus), chemical herbicide (0.8 oz glyphosate and 0.8 oz triclopyr L-1 of water) or their combination. Fertilization significantly increased pine volume growth in the Lower Coastal Plain (LCP, 2.67-4.01 m3ha-1yr-1) and the Upper Coastal Plain/ Piedmont (UCPIE, 0.20-3.72 m3ha-1yr-1). Chemical herbicide application in both the LCP (0.34-4.87 m3 ha-1yr-1) and UCPIE (0.89-1.97 m3 ha-1yr-1) also significantly increased pine volume. Chemical herbicide application, individually and combined, did not result in significant decreases in herbaceous vegetation, but reduced woody vegetation by up to -2.40 m3 ha-1yr-1 in the LCP and -5.67 m3 ha-1yr-1 in the UCPIE. Consequently, we suggest that competing vegetation response should be considered within site-specific management plans aimed at maximizing pine productivity.

White-tailed deer (Odocoileus virginianus) nutritional carrying capacity over two decades after exclusion

Studies on the impacts of white-tailed deer (Odocoileus virginianus; hereafter deer) herbivory on vegetation biomass and nutritional availability are limited. Considering deer can shift plant species composition and abundance through selective browsing, we sought to investigate whether deer could influence their own nutritional carrying capacity. Using paired control and exclosure experimental units constructed in 2000 on three Wildlife Management Areas in the Upper Coastal Plain, Lower Coastal Plain, and Mississippi Alluvial Valley (hereafter Delta) ecoregions of Mississippi, we collected biomass samples following methods initially used on the sites in 2005. Biomass data were collected during July – August of 2021 at 15 random sampling points per experimental unit. Additionally, representative samples of each plant species were collected and analyzed for crude protein content to determine nutritional carrying capacity. By analyzing biomass data from 2005 and 2021, we found between-year differences, but no differences by treatment (exclosure vs. control). Notably, there was a simultaneous increase in shade tolerant species and decrease in shade intolerant species from 2005 to 2021, and a decrease in preferred forage species. Nutritional carrying capacity was only determined using 2021 data and revealed a lack of treatment effects. The differences between ecoregions demonstrated abundant low quality forage on both Coastal Plain sites (Upper and Lower) and a comparatively low amount of forage that was higher in quality in the Delta. Results suggest changing understory light conditions and a need for additional management if increasing available forage for deer is a desired management outcome. Specifically, regional differences in nutritional availability between the Coastal Plain sites and the Delta site illustrate the potential for active management to aid in the promotion of herbaceous understory forage species.

Effectiveness of tidal control gates in flood-prone areas during high tide appearances

Managing floods in low-lying coastal plains are challenging because of the complexity of the underlying physical processes and the combination of factors such as high tides and, severe storm events. In Malaysia, there were concerns from local people about the construction of a tidal control gate that is believed to contribute to the causes of local flooding. The performance of tidal control gates as flood control structures was studied to determine their significance and importance. The objective of this study is to evaluate the effectiveness of tidal control gates in reducing the impact of floods during high tide with severe storm events. The methodology of the study requires the usage of the hydrodynamic model using design rainfall for three scenarios with land use changes in 2015 and 2020. Three feasible scenarios were identified and further investigated. Scenario 1: without a tidal control gate; Scenario 2: with the existing tidal control gate fully open; and Scenario 3: with the existing tidal control gate fully closed. The simulation result clearly shows that the floodplain is smaller in 2015 as compared to the land use changes in 2020 because of land use permeability. In addition, the floodplain for Scenarios 2 and 3 in 2015 and 2020 is 2%–3%, respectively, smaller than that of Scenario 1 for the 20-year average recurrence interval and 3%–8%, respectively, smaller for the 100-year average recurrence interval. The results showed the influence of heavy rainfall whereby the maximum downstream discharge increment varied from 4.06% to 4.28% during high tide. Whereas the flow level for the 100-year average recurrence interval shows an increment from 0.52% to 1.53%. If the tidal control gate is not operated properly it will cause the tidal water to flow back into the upstream areas thus exposing to an increased floodplain area ranging from 2.3% to 8.4%. Which emphasizes the importance of operational methods for tidal control gate in determining its efficiency. However, further studies should also be done on the reduction of damage value involved with the construction of tidal control gate, its value in saving lives, property and in other parts of the world having different tidal variations.

20-year effects of white-tailed deer (Odocoileus virginianus) herbivory on vegetation composition and structure

Throughout the southeastern U.S., white-tailed deer (Odocoileus virginianus; hereafter deer) are the dominant herbivores and have the potential to impact vegetation communities through selective browse pressure. Previous studies regarding deer herbivory impacts focused on northeastern and midwestern U.S. forests. Additionally, most studies have observed herbivory effects over short timescales (i.e., <10 years). Therefore, we sought to determine deer herbivory effects on vegetation structure and composition among three different ecoregions in Mississippi at 0, 5, and ∼ 20 years after exclusion. In 2000, 3 pairs of experimental units were identified in each of the Upper Coastal Plain, Lower Coastal Plain, and Mississippi Alluvial Valley ecoregions. An exclosure treatment was randomly assigned within each pair (averaging 2.7 ha) with the other experimental unit a control. From May-June, vegetation structure and composition were measured among 10 systematic sampling points per plot during 2000, 2005, and 2021. While no treatment effects on vegetation composition and structure were observed, among-year differences suggested a shift in overstory canopy conditions between 2005 and 2021 towards greater basal area and canopy coverage resulting in a decrease in forbs, legumes, shade intolerant species, and high year-round deer-preferred forage species. Deer herbivory effects could have been obscured by overstory conditions, low deer densities, and similar baseline conditions reflecting past herbivory effects. Regional differences in forest structure and composition and exclosure breaches may also be responsible for the lack of treatment effects. Future studies should consider utilizing disturbance to offset prior herbivory impacts and to standardize overstory conditions.

Longitudinal scour-bar pattern in large convergent estuaries on low-lying coastal plains

A seaward decrease–increase–decrease trend in the longitudinal bed level, defined as scour-bar pattern, is observed in several large estuaries on low-lying coastal plains such as the Amazon, Yangtze and Fly. Why this pattern forms has not yet been well explained. The mechanism for the formation of this pattern is explored here using a one-dimensional morphodynamic model, with varied geometry, fluvial water discharge, sediment flux and tide. Results show that for those estuaries with bed slopes in the order of 10−5 and sediment concentration in the order of 0.1 kg m−3, bars are likely to occur for channels with relatively weak convergence and wide mouth, while scours are nearly ubiquitous. Scours are classified as fluvial and tidal based on the relative strength of river and tide, which can be distinguished by bed slope and water depth. A balance between river and tide can lead to no scours or bars. Sediment reduction and sea level rise enhances the relative strength of tide, and transition of a fluvial scour to a tidal scour may occur.

Morpho-Sedimentary Constraints in the Groundwater Dynamics of Low-Lying Coastal Area: The Southern Margin of the Venice Lagoon, Italy

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.

Cost–benefit analysis of coastal flood defence measures in the North Adriatic Sea

Abstract. The combined effect of global sea level rise and land subsidence phenomena poses a major threat to coastal settlements. Coastal flooding events are expected to grow in frequency and magnitude, increasing the potential economic losses and costs of adaptation. In Italy, a large share of the population and economic activities are located along the low-lying coastal plain of the North Adriatic coast, one of the most sensitive areas to relative sea level changes. Over the last half a century, this stretch of coast has experienced a significant rise in relative sea level, the main component of which was land subsidence; in the forthcoming decades, climate-induced sea level rise is expected to become the first driver of coastal inundation hazard. We propose an assessment of flood hazard and risk linked with extreme sea level scenarios, under both historical conditions and sea level rise projections in 2050 and 2100. We run a hydrodynamic inundation model on two pilot sites located along the North Adriatic coast of Emilia-Romagna: Rimini and Cesenatico. Here, we compare alternative extreme sea level scenarios accounting for the effect of planned and hypothetical seaside renovation projects against the historical baseline. We apply a flood damage model to estimate the potential economic damage linked to flood scenarios, and we calculate the change in expected annual damage according to changes in the relative sea level. Finally, damage reduction benefits are evaluated by means of cost–benefit analysis. Results suggest an overall profitability of the investigated projects over time, with increasing benefits due to increased probability of intense flooding in the near future.

Forest floor manipulation effects on the relationship between aggregate stability and ectomycorrhizal fungi

Forest floor and mineral soil manipulations influence the soil biogeochemical properties important for loblolly pine (Pinus taeda L.) tree growth. The impacts of forest floor manipulations on soil aggregate stability and the presence of ectomycorrhizal fungi (EMF), was assessed to elucidate the relationship between EMF abundance and aggregate stability. The study site consists of a 14-year-old loblolly pine plantation managed by Weyerhaeuser Company in the Lower Coastal Plain, approximately 8 miles east of New Bern, North Carolina, USA. The soil samples were collected from the top 7.62 cm of each soil treatment which includes three levels of forest floor retention: removed, control, and doubled and two levels of forest floor mixing with the mineral soil: mixed and unmixed. Ectomycorrhizal fungi abundance was evaluated by ester-linked fatty acid methyl ester analysis and microbial community functionality was assessed by acid-phosphatase activity measurement. Aggregate stability was assessed using the aggregate mean weight diameter approach. Results indicate that the forest floor manipulations had no significant impact on aggregate stability and EMF abundance. However, a positive relationship between EMF abundance and aggregate stability was identified. Removing the forest floor resulted in a soil bulk density increase of 0.18 g cm−3 compared to doubling the forest floor. Our results demonstrate that some mineral soil properties recover relatively quickly from forest floor manipulations. The study informs forest managers interested in how soil responds to forest floor manipulation and the interaction between EMF and aggregate stability.

Shoreline evolution from the Late Cretaceous to the Miocene: A record of eustasy, tectonics and palaeoceanography in the Gippsland Basin

AbstractWell‐developed clastic shoreline systems have been deposited in the Gippsland Basin over a 70 Ma period, from the latest Cretaceous to the present day. Twenty‐three stacked coastal units have been mapped and described in the Traralgon and Balook formations of the Latrobe and Seaspray groups. These units are made up of prograding and backstepping shoreface deposits, which, in plan view, display well‐developed strandline geometries at the terrestrial–marine interface. Shoreface deposits are interpreted to include prograding beach, barrier island and transgressive beach deposits. The lower coastal plain is characterised by persistent deposition of coals despite changes in shoreface type and significant palaeoclimate fluctuations. These coastal deposits display approximately 123 km of transgression from the Late Cretaceous shoreline at the base of the study interval to the mid Miocene Yallourn Formation near the top. The Late Cretaceous and Palaeocene shoreline deposits individually prograde and are separated by flooding surfaces reflecting eustatic changes. Overall they display long‐term backstepping behaviour (retrogradation) as a result of basin subsidence. Though shorelines of the Eocene–Miocene are distinctly transgressional, probably reflecting basin subsidence, in the mid‐Miocene they become individually and collectively progradational. A series of unconformities in the Oligocene, coupled with Miocene progradation, likely reflects a combination of a compressional tectonic regime and glacioeustatic fluctuations. Despite major changes in the tectonics and palaeoclimate, basin subsidence appears to be the dominant driver for changes in shoreline location.

Temporally Generalizable Land Cover Classification: A Recurrent Convolutional Neural Network Unveils Major Coastal Change through Time

The ability to accurately classify land cover in periods before appropriate training and validation data exist is a critical step towards understanding subtle long-term impacts of climate change. These trends cannot be properly understood and distinguished from individual disturbance events or decadal cycles using only a decade or less of data. Understanding these long-term changes in low lying coastal areas, home to a huge proportion of the global population, is of particular importance. Relatively simple deep learning models that extract representative spatiotemporal patterns can lead to major improvements in temporal generalizability. To provide insight into major changes in low lying coastal areas, our study (1) developed a recurrent convolutional neural network that incorporates spectral, spatial, and temporal contexts for predicting land cover class, (2) evaluated this model across time and space and compared this model to conventional Random Forest and Support Vector Machine methods as well as other deep learning approaches, and (3) applied this model to classify land cover across 20 years of Landsat 5 data in the low-lying coastal plain of North Carolina, USA. We observed striking changes related to sea level rise that support evidence on a smaller scale of agricultural land and forests transitioning into wetlands and “ghost forests”. This work demonstrates that recurrent convolutional neural networks should be considered when a model is needed that can generalize across time and that they can help uncover important trends necessary for understanding and responding to climate change in vulnerable coastal regions.

Coastal Landform Constrains Dispersal in Mangroves

Mangrove forests are dynamic ecosystems found along low-lying coastal plains along tropical, subtropical, and some warm-temperate coasts, predominantly on tidal flats fringing deltas, estuaries, bays, and oceanic atolls. These landforms present varied hydrodynamic and geomorphological settings for mangroves to persist and could influence the extent of within-site propagule transport and subsequent local regeneration. In this study, we examined how different landform characteristics may influence local genetic diversity, kinship, and neighborhood structure of mangrove populations. To do so, we considered independent populations of Avicennia marina, one of the most abundant and widespread mangrove species, located in estuarine and coastal bay environments spread across the Western Indian Ocean region. A transect approach was considered to estimate kinship-based fine-scale spatial genetic structure using 15 polymorphic microsatellite markers in 475 adult A. marina trees from 14 populations. Elevated kinship values and significant fine-scale structure up to 30, 60, or 90 m distances were detected in sheltered systems void of river discharge, suggesting a setting suitable for very local propagule retention and establishment within a neighborhood. Slopes of a linear regression over restricted distance within 150 m were significantly declining in each sheltered transect. Contrastingly, such a spatial structure has not been detected for A. marina transects bordering rivers in the estuarine systems considered, or alongside partially sheltered creeks, suggesting that recruitment here is governed by unrelated carried-away mixed-origin propagules. South African populations showed strong inbreeding levels. In general, we have shown that A. marina populations can locally experience different modes of propagule movement, explained from their position in different coastal landforms. Thus, the resilience of mangroves through natural regeneration is achieved by different responses in coastal landforms characterized by different hydrodynamic conditions, which can be important information for their management and protection within the variety of coastal environments.

Hydrologic Effects on Growth and Hatching Success of Age‐0 Channel Catfish in the Tallapoosa River Basin: Implications for Management in Regulated Systems

AbstractWe assessed the effects of hydrology on growth and hatching success of age‐0 Channel Catfish Ictalurus punctatus in regulated and unregulated reaches of the Tallapoosa River basin, Alabama. Age‐0 Channel Catfish (N = 91) were collected from sites in both the Coastal Plain and Piedmont regions in fall 2003 and fall 2005. Lapillus otoliths were used to estimate the daily ages of age‐0 Channel Catfish, for which hatch dates were back‐calculated. We performed growth analysis to determine growth histories of each fish at 20‐d increments from hatch. Across the 2 years of sampling, Channel Catfish hatches were documented from June 7 to September 15. Ages and growth rates of age‐0 Channel Catfish ranged from 20 to 126 d and 0.60 to 1.5 mm/d, respectively. In general, growth was highest among age‐0 Channel Catfish from unregulated sites in the lower Coastal Plain, lowest among fish from unregulated sites in the Piedmont, and intermediate from regulated sites in the Piedmont. Successful hatching typically occurred during periods when mean discharges were in the upper two quartiles of flows for each site but not during exceptionally high peaks in flow. Physiographic province, the frequency of high pulses, and the number of flow reversals were the most important factors influencing the growth of recently hatched Channel Catfish. Results suggest that a low to moderate frequency of high pulses (25–150 pulses per 20‐d increment) and a moderate number of flow reversals (~100–175 reversals per 20‐d increment) enhances early growth of Channel Catfish in the Tallapoosa River system. Managing flow, when possible, to minimize large releases of water that result in exceptionally high pulses and providing minimal hydropeaking may improve hatching success during the Channel Catfish spawning season.

From Glaciated Landscape to Unglaciated Seascape: Transformation of the Hambergbreen–Hambergbukta Area, SE Spitsbergen, 1900–2017

In 1900 the present Hambergbukta fjord did not exist and its basin was filled with the huge Hambergbreen glacier. The glacier then experienced progressive recession during a period of climate warming. The retreat of its front was perhaps the most spectacular expression of this recession. Eventually, a small bay named Hambergbukta appeared in 1936. By the 1950s the bay had become transformed into a new fjord 6 to 7 km long and 3 to 4 km wide. Its basin was progressively abandoned by the glacier and flooded by the sea. After 1961, the glacier surged and refilled the fjord basin with a fissured glacier tongue, and the fjord coastline became occupied by lateral ice-moraine ridges. Since 1970, the Hambergbreen glacier has undergone progressive recession again, resulting in the formation of the present-day Hambergbukta fjord. There exist significant differences in the landforms found between the northern and southern fjord coastlines: The former consists mainly of preserved lateral ice moraine ridges, whereas in the latter the ice cores have melted and low coastal plains have formed. This transformation continues to the present day. The Hamberbukta fjord has currently achieved its largest dimensions (including length), while being closed off from more inland areas by two tidewater glaciers: remnants of the Hambergbreen and Sykorabreen glaciers, the latter being a tributary glacier of the former in the 1980s.

Monitoring seasonal transpiration drying of loblolly and slash pine with time domain reflectometry

The moisture content (MC) of felled trees has a direct impact on transportation costs and efficiency. Transpirational (or field) drying of fallen trees, to reduce MC and subsequently improve the economics of transport can be employed; however, an understanding of seasonal drying rates is required. Typically load cells have been used to track moisture changes in bundles of logs but where access is limited this approach is impractical. Time-domain reflectometry (TDR) provides an alternative approach and was used to monitor seasonal changes in transpirational drying rates for felled loblolly and slash pine at a Lower Coastal Plain site in Florida and loblolly pine at a Piedmont site in Georgia on a weekly basis for approximately one year. Different transpirational drying rates and minimum MC’s were observed by season. Drying rates observed during summer, fall and spring, at both test locations, indicate that after three weeks an equilibrium (or minimum) MC is achieved. Winter drying is slower, and up to 5 weeks in the field (or even longer) may be required. Post equilibrium felled log moisture content continued to vary during most seasons with rainfall events the most probable cause. TDR provides a viable approach for monitoring transpirational drying and subsequent MC changes in felled trees.

Assessing Po River Deltaic Vulnerability Using Earth Observation and a Bayesian Belief Network Model

Deltaic systems are broadly recognized as vulnerable hot spots at the interface between land and sea and are highly exposed to harmful natural and manmade threats. The vulnerability to these threats and the interactions of the biological, physical, and anthropogenic processes in low-lying coastal plains, such as river deltas, requires a better understanding in terms of vulnerable systems and to support sustainable management and spatial planning actions in the context of climate change. This study analyses the potential of Bayesian belief network (BBN) models to represent conditional dependencies in vulnerability assessment for future sea level rise (SLR) scenarios considering ecological, morphological and social factors using Earth observation (EO) time series dataset. The BBN model, applied in the Po Delta region in the northern Adriatic coast of Italy, defines relationships between twelve selected variables classified as driver factors (DF), land cover factors (LCF), and land use factors (LUF) chosen as critical for the definition of vulnerability hot spots, future coastal adaptation, and spatial planning actions to be taken. The key results identify the spatial distribution of the vulnerability along the costal delta and highlight where the probability of vulnerable areas is expected to increase in terms of SLR pressure, which occurs especially in the central and southern delta portion.