Coastal Floodplain Research Articles

Effects of Scale and Input Data on Assessing the Future Impacts of Coastal Flooding: An Application of DIVA for the Emilia-Romagna Coast

This paper assess sea-level rise related coastal flood impacts for Emilia-Romagna (Italy) using the Dynamic Interactive Vulnerability Assessment (DIVA) modeling framework and investigate the sensitivity of the model to four uncertainty dimensions, namely (1) elevation, (2) population (3) vertical land movement (4) scale and resolution of assessment. A one-driver-at-a-time sensitivity approach is used in order to explore and quantify the effects of uncertainties in input data and assessment scale on model outputs. Of particular interest is the sensitivity of flood risk estimates when using datasets of different resolution. The change in assessment scale is implemented through the use of a more detailed digital coastline and input data for the coastline segmentation process. This change leads to a 35-fold increase in the number of coastal segments and in a more realistic spatial representation of coastal flood impacts for the Emilia-Romagna coast. Furthermore, the coastline length increases by 43%, considerably influencing adaptation costs (construction of dikes). With respect to input data our results show that by the end of the century coastal flood impacts are more sensitive to variations in elevation and vertical land movement data than to variations in population data in the study area. The inclusion of local information on human induced subsidence rates increases the relative sea-level by 60cm in 2100, resulting in coastal flood impacts that are up to 25% higher compared to those generated with the global DIVA values, which mainly account for natural processes. The choice of one elevation model over another can result in differences of approximately 45% of the coastal floodplain extent and up to 50% in flood damages by 2100. Our results emphasize that the scale of assessment and resolution of the input data can have significant implications for the results of coastal flood impact assessments. Understanding and communicating these implications is essential for effectively supporting decision makers in developing long-term robust and flexible adaptation plans for future changes of highly uncertain scale and direction.

Changes in soil organic carbon fractions after remediation of a coastal floodplain soil

Coastal floodplain soils and wetland sediments can store large amounts of soil organic carbon (SOC). These environments are also commonly underlain by sulfidic sediments which can oxidise to form coastal acid sulfate soils (CASS) and contain high concentrations of acidity and trace metals. CASS are found on every continent globally except Antarctica. When sulfidic sediments are oxidised, scalds can form, which are large bare patches without vegetation. However, SOC stocks and fractions have not been quantified in these coastal floodplain environments. We studied the changes in soil geochemistry and SOC stocks and fractions three years after remediation of a CASS scald. Remediation treatments included raising water levels, and addition of either lime (LO) or lime and mulch (LM) relative to a control (C) site. We found SOC concentrations in the remediated sites (LO and LM) were more than double than that found at site C, reflected in the higher SOC stocks to a depth of 1.6 m (426 Mg C/ha, 478 Mg C/ha and 473 Mg C/ha at sites C, LO and LM, respectively). The particulate organic C (POC) fraction was higher at sites LO and LM due to increased vegetation and biomass inputs, compared to site C. Reformation of acid volatile sulfide (AVS) occurred throughout the profile at site LM, whereas only limited AVS reformation occurred at sites LO and C. Higher AVS at site LM may be linked to the additional source of organic matter provided by the mulch. POC can also potentially contribute to decreasing acidity as a labile SOC source for Fe3+ and SO42− reduction. Therefore, coastal floodplains and wetlands are a large store of SOC and can potentially increase SOC following remediation due to i) reduced decomposition rates with higher water levels and waterlogging, and ii) high C inputs due to rapid revegetation of scalded areas and high rates of biomass production. These results highlight the importance of maintaining vegetation cover in coastal floodplains and wetlands for sequestering SOC.

Detection of Flood Hazard in Urban Areas Using GIS: Izmir Case

The aim of this study is to predict the potential flood-hazard areas using Shuttle Radar Topography Mission - Digital Elevation Model (SRTM-DEM). The study area is the province of Izmir. SRTM-DEM of the Izmir Province has 90 m of grid size resolution; 45 m of horizontal accuracy; and 15 m of vertical accuracy. Within this study, obtaining spatial information on flood-hazard by using Izmir digital terrain models and by 3D analysis that will help to achieve the regional flood hazard management scheme is aimed. Flood-hazard areas have been identified by the use of digital elevation model covering the study area. The main rivers in the study area are Gediz, Kucuk Menderes and Bakircay that creates the coastal flood plains. In order to estimate the spatial distribution of flood-hazard areas in İzmir, five factors are used: flow accumulation, land use, slope, rainfall intensity, and elevation. The classic hydrological modelling approach was applied to determine the rainfall intensity; rainfall intensity of study region is created with the average amount of total rainfall intensity of fifteen stations in the two basins per minute using the interpolation method (spline interpolation). By the digitizing rivers, topography, flow direction and flow accumulation, as well as the flood detention areas are determined. These factors were combined with the weighted overlay method to determine categorized flood-hazard areas. As a result, possible flood-hazard areas have been determined in the case of Izmir Province.

Reconstructing input for artificial neural networks based on embedding theory and mutual information to simulate soil pore water salinity in tidal floodplain

AbstractSoil pore water salinity plays an important role in the distribution of vegetation and biogeochemical processes in coastal floodplain ecosystems. In this study, artificial neural networks (ANNs) were applied to simulate the pore water salinity of a tidal floodplain in Florida. We present an approach based on embedding theory with mutual information to reconstruct ANN model input time series from one system state variable. Mutual information between system output and input was computed and the local minimum mutual information points were used to determine a time lag vector for time series embedding and reconstruction, with which the mutual information weighted average method was developed to compute the components of reconstructed time series. The optimal embedding dimension was obtained by optimizing model performance. The method was applied to simulate soil pore water salinity dynamics at 12 probe locations in the tidal floodplain influenced by saltwater intrusion using 4 years (2005–2008) data, in which adjacent river water salinity was used to reconstruct model input. The simulated electrical conductivity of the pore water showed close agreement with field observations (RMSE and ), suggesting the reconstructed input by the proposed approach provided adequate input information for ANN modeling. Multiple linear regression model, partial mutual information algorithm for input variable selection, k‐NN algorithm, and simple time delay embedding were also used to further verify the merit of the proposed approach.

Growth and nutrient uptake of perennial crops in a paludicultural approach in a drained Mediterranean peatland

Combining peatland rewetting with biomass cropping (paludiculture) is one strategy to remove nutrient surpluses from soil/water and stimulate peat-forming vegetation. This approach was tested in the Massaciuccoli Lake Basin (Tuscany, Italy), a coastal floodplain artificially drained for agricultural purposes since 1930, where land reclamation and continuous cropping have contributed to considerable peat degradation and water eutrophication due to nutrient enrichment of surface waters. An experimental trial was established in spring 2012 with three perennial rhizomatous grasses (PRG) (Phragmites australis, Miscanthus×giganteus, Arundo donax) and two woody species managed as short-rotation coppice (SRC) (Salix alba “Dimitrios”, Populus×canadensis “Oudenberg”), aimed to provide biomass for various bioenergy supply chains. A conventionally cultivated annual crop (maize) was the control. The aim of this study was to compare the sustainability of the proposed paludiculture systems to that of conventional annual crops on the basis of yield and nutrient-removal capability. This two-year field study evaluated yields, nutrient concentrations and uptake (N and P) of the crops. Over the two years, A. donax had the highest mean biomass yield (35Mgha−1), N uptake (367kgha−1), and P uptake (54kgha−1). SRCs had the lowest nutrient uptake in both years. Among grasses, the highest N concentration was recorded in A. donax leaves in 2013 (N: 2.41%), while P concentration was greater in S. alba branches (P: 0.39%). The average aboveground biomass of maize was 17.5Mgha−1, while the nutrient uptakes were equal to 194 and 27kgha−1 for N and P, respectively.Thus, the performances of paludiculture systems were generally encouraging and could represent an important alternative for restoring and managing former drained peatlands in a suitable product chain.

Case studies of geophysical imaging for road foundation design on soft soils and embankment risk assessment

Population growth along the coast of eastern Australia has increased demand for new and upgraded transport infrastructure within intervening coastal floodplains and steeper hinterland areas. This has created additional challenges for road foundation design.The floodplain areas in this region are underlain by considerable thicknesses of recently deposited alluvial and clayey marine sediments. If characterisation of these deposits is inadequate they can increase road construction costs and affect long-term road stability and serviceability. Case studies from a major coastal highway upgrade demonstrate how combining surface wave seismic and electrical geophysical imaging with conventional geotechnical testing enhances characterisation of these very soft and soft soils. The geophysical results also provide initial foundation design parameters such as void ratio and pre-consolidation pressure.A further significant risk issue for roads is potential embankment instability. This can occur during new road construction or when upgrades of existing embankments are required. Assessing the causes of instability of existing steeper embankments with drilling and probing is often difficult and costly due to access and safety problems. In these situations combinations of electrical, ground penetrating radar and P-wave seismic imaging technologies can rapidly provide information on the likely conditions below both the roadway and embankment. Case studies show the application of these technologies on two unstable road embankments.It is concluded that the application of both geophysical imaging and geotechnical testing is a cost-effective enhancement for site characterisation of soft soils and for risk assessment of potentially unstable embankments. This approach overcomes many of the current limitations of conventional methods of site investigation that provide point location data only. The incorporation of geophysics into a well crafted site investigation allows concentration on fewer but higher quality soil probings and geotechnical boreholes.

Evaluation of the U.S. Geological Survey standard elevation products in a two-dimensional hydraulic modeling application for a low relief coastal floodplain

Summary Growing use of two-dimensional (2-D) hydraulic models has created a need for high resolution data to support flood volume estimates, floodplain specific engineering data, and accurate flood inundation scenarios. Elevation data are a critical input to these models that guide the flood-wave across the landscape allowing the computation of valuable engineering specific data that provides a better understanding of flooding impacts on structures, debris movement, bed scour, and direction. High resolution elevation data are becoming publicly available that can benefit the 2-D flood modeling community. Comparison of these newly available data with legacy data suggests that better modeling outcomes are achieved by using 3D Elevation Program (3DEP) lidar point data and the derived 1 m Digital Elevation Model (DEM) product relative to the legacy 3 m, 10 m, or 30 m products currently available in the U.S. Geological Survey (USGS) National Elevation Dataset. Within the low topographic relief of a coastal floodplain, the newer 3DEP data better resolved elevations within the forested and swampy areas achieving simulations that compared well with a historic flooding event. Results show that the 1 m DEM derived from 3DEP lidar source provides a more conservative estimate of specific energy, static pressure, and impact pressure for grid elements at maximum flow relative to the legacy DEM data. Better flood simulations are critically important in coastal floodplains where climate change driven storm frequency and sea level rise will contribute to more frequent flooding events.

Quantifying changes to historic fish habitat extent on north coast NSW floodplains, Australia

Global degradation of coastal ecosystems is influencing the provision of ecosystem services, including fisheries maintenance services. Degradation of the Australian coastal zone and its resources following European occupation has been recognised for some time. This includes the loss of ecologically important coastal wetlands, which have strong trophic and habitat links to fisheries. In NSW, structural flood mitigation works are a principle driver of the decline of coastal wetlands; however, little action has been taken to quantify the extent of decline due to limited information of the pre-European settlement extent of coastal wetlands. We use spatial data sets in GIS to quantify prime fish habitat and calculate the loss of fish habitat for the large coastal floodplains of northern NSW, which are significant contributors to the commercial and recreational fisheries of NSW. The technique is validated by comparison with early maps of wetland distribution. We identified pre-European distribution of available fish habitat of approximately 477,000 ha, of which 87,000 ha was identified as prime fish habitat. Approximately 62,000 ha of prime fish habitat was impacted by drainage of the coastal floodplains in association with flood mitigation works which intensified in the mid-1950s and were largely completed by 1971, equating to a loss of approximately 72 % of prime fish habitat. The declining value of the ecosystem services provided by prime fish habitat following drainage is likely to be substantial. Some actions have taken place to restore the functions of this habitat although significant opportunities remain to reverse this decline through management actions that restore natural drainage and reinstate tidal exchange. These actions become even more important as pressures on coastal wetlands increase with climate change and associated sea-level rise.

A Bayesian network model for assessments of coastal inundation pathways and probabilities

AbstractCoastal flood assessments are often required to describe networks of flood sources, pathways and receptors. This can be challenging within traditional numerical modelling approaches. In this paper, we assess coastal flood plains as networks of interlinked elements using a Bayesian network (Bn) model. The Bn model describes flood pathways and estimate flood extents for different extreme events and is constructed from a quasi‐two‐dimensional Source – Pathway – Receptor (2D SPR) systems diagram. The Bn model is applied in Teignmouth in the UK, a coastal flood plain of typical complexity. It identifies two key flood pathways and assesses their sensitivity to changes in sea levels, beach widths and coastal defences. The process of 2D SPR and Bn model construction helps identify gaps in flood plain understanding and description. The Bn model quantifies inundation probabilities and facilitates the rapid identification of critical pathways and elements before committing resources to further detailed analysis. The advantages, utility and limitations of the Teignmouth Bn model are discussed. The approach is transferable and can be readily applied in localscale coastal flood plains to obtain a systems‐level understanding and inform numerical modelling assumptions.

Geochemistry of stream sediments within the reclaimed coastal floodplain as indicator of anthropogenic impact (River Neretva, Croatia)

Purpose This study used multi-element signatures of stream sediments to assess both natural and human-induced impact on fluvial system in the River Neretva delta receiving environment over time. The river basin actually comprises several sub-catchments, and the geochemical features of major elements, trace metals radiometric and mineralogical characterisation of river bed sediments were used to assist the interpretation of the environment of deposition and its subsequent modifications caused by various anthropogenic pressures within the river basin.

The current distribution pattern of Biomphalaria tenagophila and Biomphalaria straminea in the northern and southern regions of the coastal fluvial plain in the state of São Paulo

We analyze the current distribution of snails from genus Biomphalaria in the north and south of the coastal fluvial plain in the state of São Paulo, which is part of a large coastal floodplain. Data from twenty-nine collection sites confirmed that the freshwater body in both regions is colonized by Biomphalaria tenagophila and Biomphalaria straminea, which are natural intermediate hosts of Schistosoma mansoni. The abundance of B. straminea in collection sites where only B. tenagophila had previously been recorded indicates the potential for B. straminea to expand in the region. While quantitative analysis of the number of specimens per species showed that local growth of B. tenagophila populations occurs during periods with little rainfall, there is a greater risk of B. tenagophila populations spreading between different water bodies during rainy periods, when heavy rainfall results in water levels rising in the main rivers and flooding caused by water flowing from the Serra do Mar mountain range to the coastal plain. The temperature increase caused by global climate changes and the consequent increasing frequency of high-water levels and floods can be expected to affect the distribution of these snails on the coastal fluvial plain, leading to the risk of a change in the autochthonous transmission pattern of schistosomiasis in the region.

Estimating the long-term historic evolution of exposure to flooding of coastal populations

Abstract. Coastal managers face the task of assessing and managing flood risk. This requires knowledge of the area of land, the number of people, properties and other infrastructure potentially affected by floods. Such analyses are usually static; i.e. they only consider a snapshot of the current situation. This misses the opportunity to learn about the role of key drivers of historical changes in flood risk, such as development and population rise in the coastal flood plain, as well as sea-level rise. In this paper, we develop and apply a method to analyse the temporal evolution of residential population exposure to coastal flooding. It uses readily available data in a GIS environment. We examine how population and sea-level change have modified exposure over two centuries in two neighbouring coastal sites: Portsea and Hayling Islands on the UK south coast. The analysis shows that flood exposure changes as a result of increases in population, changes in coastal population density and sea level rise. The results indicate that to date, population change is the dominant driver of the increase in exposure to flooding in the study sites, but climate change may outweigh this in the future. A full analysis of changing flood risk is not possible as data on historic defences and wider vulnerability are not available. Hence, the historic evolution of flood exposure is as close as we can get to a historic evolution of flood risk. The method is applicable anywhere that suitable floodplain geometry, sea level and population data sets are available and could be widely applied, and will help inform coastal managers of the time evolution in coastal flood drivers.

Identification of types of buffaloes available in Kanihari buffalo pocket of Mymensingh district

The buffaloes are reared by many races under diverse agro-climatic conditions of Bangladesh. The buffaloes of Bangladesh are mostly indigenous in origin. Both the swamp and river type buffaloes are found in Bangladesh and they can be found throughout the country. However, their concentration is higher in coastal part, Meghna-Ganga and Jamuna-Brahamaputra flood plain, subsequently forming buffalo pockets. This study was conducted to identify the types of buffaloes and the sources of breeding buffaloes in one of those buffalo pockets called Kanihari buffalo pocket situated in Mymenshing district. Direct interviewing method was used to collect the data from the owner of the buffaloes. According to the body shape, coat color and horn pattern, buffaloes of this region were categorized into different categories. Abundant natural green grasses in the river bank of old Brahammaputra gave this area as a shape of a buffalo pocket. This pocket does not have any distinct breed and the buffalo population is mostly mixed and exotic. Introduction of swamp germplasm occurred when buffalo cows are temporarily migrated to Bathan area of Sylhet. Morphometric characteristics (coat color, horn pattern and body appearance) of Type-1, Type-2 and Type-3 buffaloes are similar to Murrah group (Murrah and Nili- Ravi), Surti group and indigenous river type buffaloes, respectively. This is the first study which identifies and morphologically characterizes the buffalo population in Kanihari buffalo pocket; however, in depth genotypic study is required in order to identify the origin or breeds available in this area.Res. Agric., Livest. Fish.2(1): 109-115, April 2015

Morphological adaptations of 3.22 Ga-old tufted microbial mats to Archean coastal habitats (Moodies Group, Barberton Greenstone Belt, South Africa)

Microbial life was well established and widespread by the Paleoarchean; however, the degree of evolutionary advancement such as microbial motility, intra- and inter-species interactions, phototropism, or oxygenic photosynthesis by that time remains highly debated. The 3.22 Ga Moodies Group in the Barberton Greenstone Belt (BGB, South Africa) are Earth's oldest well-preserved siliciclastic tidal deposits. They exhibit a unique assemblage of microbial mats, providing an excellent opportunity to decipher the morphological adaptations of microbial communities to different paleoenvironmental settings. The fossil mats are preserved as kerogenous laminations (0.5–1mm thick) that can be traced laterally for ∼15km in a ∼1000m-thick succession of fine- to coarse-grained tidal sandstones and conglomerates. We here present a detailed stratigraphic and depositional facies analysis, documenting the association of the three principal mat morphotypes with specific environmental settings: (1) planar-type in coastal floodplain, (2) wavy-type in intertidal, and (3) tufted-type in upper inter- to supratidal facies. All mat types indicate a flourishing phototrophic biota; moreover, the tufted morphology suggests an intricate level of coordinated growth commonly known from cyanobacterial mats in modern environments.

Vertical accuracy assessment of freely available digital elevation models over low-lying coastal plains

The frequency of coastal flood damages is expected to increase significantly during the twenty-first century as sea level rises in the coastal floodplain. Coastal digital elevation model (DEM) data describing coastal topography are essential for assessing future flood-related damages and understanding the impacts of sea-level rise. The Shuttle Radar Topography Mission (SRTM) and Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM) are currently the most accurate and freely available DEM data. However, an accuracy assessment specifically targeted at DEMs over low elevation coastal plains is lacking. The present study focuses on these areas to assess the vertical accuracy of SRTM and ASTER GDEM using Ice, Cloud, and land Elevation Satellite, Geoscience Laser Altimeter System (ICESat/GLAS) and Real Time Kinematic (RTK) Global Positioning System (GPS) field survey data. The findings show that DEM accuracy is much better than the mission specifications over coastal plains. In addition, optical remote sensing image analysis further reveals the relationship between DEM vertical accuracy and land cover in these areas. This study provides a systematic approach to assess the accuracy of DEMs in coastal zones, and the results highlight the limitations and potential of these DEMs in coastal applications.

Seawater inundation of coastal floodplain sediments: Short-term changes in surface water and sediment geochemistry

Coastal floodplains are highly vulnerable to seawater inundation as a result of storm surge and sea-level rise due to their low elevation and proximity to the coastline. Intact soil cores from a levee, acid-sulfate soil scald and four backswamp sites on a coastal floodplain in eastern Australia were inundated with artificial seawater treatments (0%, 50% and 100%) for 14days to examine the short term consequences for surface water and floodplain sediment geochemistry. All sites displayed an initial decrease in surface water pH following inundation with 50% and 100% seawater. In addition, higher concentrations of trace metals (Al, Fe, Mn, Ni and Zn) were observed in most sites inundated with 50% or 100% seawater. This was generally attributed to competitive exchange and desorption of trace metals from sediments due to the higher ionic strength of the seawater solutions and upward diffusive flux of metals from the sediments to surface waters. At one backswamp site, reductive processes had established by day 7, which also resulted in elevated Fe2+ concentrations in the overlying surface waters. Transmission electron microscopy (TEM) identified the presence of poorly crystalline ferrihydrite and schwertmannite, and goethite and jarosite. These meta-stable Fe(III) minerals can act as a source of metals for desorption and can also be readily reduced and act as a source of Fe2+ to surface waters. Importantly, inundation with either 50% or 100% seawater resulted in a similar magnitude of acidity and trace metal mobilisation. The data suggest that an inundation event of ~0.2m depth with either 50% or 100% seawater could cause a pulse mobilisation of up to 64.8 and 9.1kgha−1 of Fe and Al, respectively — quantities of similar magnitude to previous estimates of annual drainage fluxes from similar backswamps. This study suggests that the short term inundation of coastal floodplain sediments by either brackish water or seawater will result in rapid declines in surface water quality as a result of increased liberation of acidity and trace metals.

Bio-energy, Productivity and Economics of rice (Oryza sativaL.)-based Cropping Systems in Coastal Flood Plain of West Bengal, India

A field experiment was carried out at farmers’ field in coastal saline zone of West Bengal, India during 2011–12 and 2012–13 with four cropping systems viz. rice-greengram, rice-sunflower, rice-sunflower+greengram and rice-lady's finger. Rice-lady's finger system recorded significantly higher rice equivalent yield, system productivity in both the years. Significantly higher net return ( 1, 05, 670 ha−1) was obtained in rice-lady's finger cropping system, followed by rice greengram, whereas B: C ratio was found at par. Among the management components fertilizer consumed maximum energy followed by operational labour and land preparation. Energy consumption was found significantly higher in rice-lady's finger system (44, 902 MJ ha−1) and lowest in rice-greengram system (29, 005 MJ ha−1). Total bioenergy output follows the order: rice-lady's finger>rice-sunflower>rice-sunflower+greengram>rice-greengram. But this order was reversed for energy-use efficiency (EUE). Significantly higher specific energy was recorded in rice-sunflower system (3415 MJ t−1) and it was the most energy-investment intensive among them. However, significantly higher energy productivity was observed in rice-lady's finger system (0.63 kg MJ−1) and lowest in rice-greengram (0.30 kg MJ−1). Regarding energy intensiveness the results were contrary to EUE. Rice-lady's finger system was emerged as most energy intensive system as compared to other three cropping systems and the rice-greengram system is the least. It can be concluded that though the yield and net return in rice-lady's finger system were higher than other system, the rice-greengram system is more suitable cropping system in constrains prone coastal saline zone with limited irrigation facilities due to low requirement of non-renewable energy, higher EUE and benefit-cost ratio.

Introduction, Systematic Paleontology, and Geological Context of Vintana Sertichi (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar

ABSTRACT—Vintana sertichi is a sudamericid gondwanatherian mammal known only from the Upper Cretaceous (Maastrichtian) Maevarano Formation in the Mahajanga Basin of northwestern Madagascar. It is based on a single specimen, a well-preserved and virtually complete cranium discovered in 2010 near Lac Kinkony. The cranium is superficially bizarre and constitutes the only cranial remains of the poorly known, phylogenetically enigmatic Gondwanatheria, which are otherwise known only from isolated teeth and fragmentary dentaries. Gondwanatheria are represented by seven other monotypic genera assigned to two families (Ferugliotheriidae and Sudamericidae). Historically, this clade was assigned to Xenarthra, Paratheria (as a sister group to Xenarthra), Multituberculata, Allotheria (as a sister group to Multituberculata), Mammalia incertae sedis, and, most recently, back to Multituberculata or a close relative of Multituberculata. The craniodental evidence provided by Vintana supports inclusion in Sudamericidae, the monophyly of Gondwanatheria, and the position of Gondwanatheria as nested within or sister to Multituberculata. In addition to briefly reviewing the taxonomic composition and phylogenetic history of Gondwanatheria, this introductory chapter sets the stage for the other chapters in the volume by (1) briefly summarizing the inferred life habits of gondwanatherians; (2) reviewing the systematic paleontology of V. sertichi; and (3) providing overviews of the discovery of the holotypic specimen, its preservation, its preparation, and the imaging and measurement techniques used to study it. The chapter closes with an overview of the geological context of V. sertichi, which indicates that the species lived in a coastal floodplain environment and in a highly seasonal, semiarid climate.

Elucidating multidecadal saltwater intrusion and vegetation dynamics in a coastal floodplain with artificial neural networks and aerial photography

AbstractSaltwater intrusion has been recognized as a major driver of ecological regime shifts in coastal wetlands, but few studies have incorporated long‐term salinity modelling data into the understanding of vegetation dynamics. This study uniquely combined artificial neural network (ANN) modelling and time series of aerial photographs to elucidate saltwater intrusion and mangrove encroachment into the freshwater floodplain of the Loxahatchee River over a period of six decades. Three ANN models were developed to simulate river salinity on a daily time step using freshwater inflow, rainfall and tide as inputs. With 8 years of measured data for training and testing, the ANN models demonstrated comparable or superior model performance for salinity simulation to their hydrodynamic counterparts. Modelling of historical salinity (1948–2011) using the ANNs indicated that the intensity of saltwater intrusion clearly correlated with watershed hydrology, which, in turn, was linked to historical watershed alterations and regional rainfall variability. Interpretation of the 1940, 1953, 1964, 1979, 1985 and 1995 aerial photographs revealed the progressive encroachment of mangroves and displacement of bald cypress and freshwater communities in the floodplain. The spatial extent of mangrove encroachment was related to the increasing mortality of bald cypress under the chronic effect of cumulative salinity exposure. The ecohydrological controls over vegetation changes in the Loxahatchee River support the ongoing ecosystem restoration programme, which aims to achieve incremental freshwater flow targets to protect and restore the floodplain ecosystem. Copyright © 2014 John Wiley & Sons, Ltd.

A conceptual model of the species composition of the original riparian rainforest of the Clarence River Floodplain, New South Wales.

The riparian rainforest on the streamside levees of the coastal floodplain of the Clarence River on the North Coast of New South Wales was cleared during the 1860s by small landholders seeking fertile land. Only three small remnants remain. Using a combination of historical species lists, corner trees from surveyors' portion plans, habitat information and the NSW Scientific Committee's (1999) determination for lowland rainforest on floodplain a conceptual model of the original distribution of rainforest suballiances on the levees of the Clarence River coastal floodplain is proposed. Cunninghamia (2014) 14: 153-178 doi:10.7751/cunninghamia.2014.14.008