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The frequency and intensity of coastal flooding is expected to accelerate in low-elevation coastal areas due to sea level rise. Coastal flooding due to wave runup affects coastal ecosystems and infrastructure, however it can be difficult to monitor in remote and vulnerable areas. Here we use a camera-based system to monitor wave runup as part of the after-storm recovery of an eroded beach on the Texas coast. We analyze high-temporal resolution images of the beach using Convolutional Neural Network (CNN)-based semantic segmentation to study the stochastic properties of runup-driven flooding events. In the first part of this work, we focus on the application of semantic segmentation to identify water and runup events. We train and validate a CNN with over 500 manually classified images, and introduce a post-processing method to reduce false positives. We find that the accuracy of CNN predictions of water pixels is around 90% and strongly depend on the number and diversity of images used for training.

The Slop Bowl marsh in the Brazoria National Wildlife Refuge provides extraordinarily high quality, heavily used bird habitat. Much of this habitat has experienced hypersaline conditions due to both hydrologic alteration by humans and a rapidly and changing physical environment over the past several decades. Oil and natural gas extraction activities have resulted in excavation and channelization along pipelines and hydrologic obstruction by an access road. In addition, subsidence along growth faults has altered hydrologic pathways and lowered surface elevations in the center of the marsh. Our objective was to understand the underlying processes that contribute to hypersaline conditions and to evaluate possible restoration alternatives to reduce the severity of those conditions. Accordingly, we conducted extensive field and hydrologic modeling efforts, and identified the past, present, and future of this marsh habitat under a baseline scenario. We then compared various restoration action scenarios against this baseline. We found that, beginning in about 15 years, relative sea level rise will improve the hydrologic conditions by enhancing tidal flushing. However, if fill material is continually added to elevate the obstructing road as the sea rises, this hydrologic relief may never be realized. Moreover, we found that if a drought occurs during this critical period, a difference of only a few centimeters in the relative water level and road elevation, or changes in marsh surface elevations driven by fault motion and subsidence, may have catastrophic consequences. The modeling also suggests that several potential interventions can bridge this gap over the next 15 years and beyond. Actions that improve tidal circulation, reduce salinity, and enhance marsh accretion are being developed by the project team to enhance and restore habitat in the near term. The most optimal approaches evaluated thus far include the installation of culverts at critical locations, the excavation of a small channel, the modification of flow pathways, and the beneficial use of sediments and vegetative plantings. We conclude that, under specific circumstances or at unique locations such as the Slop Bowl marsh, sea level rise can be leveraged to improve coastal wetland health.

Summary Infrastructure must become more resilient as the global climate changes and also more affordable in the economic and political context of a post-COVID world. We can solve this dual challenge and drive global infrastructure investment into a more sustainable direction by taking our cues from Nature.

Bays and estuaries often rely on freshwater inflows to maintain the salinity balance necessary to sustain their fisheries. Reduced freshwater inflows, particularly during summer seasons, can be detrimental to the health of these systems. Despite an extensive network of streamflow gauges in the U.S., many coastal watersheds remain ungauged. Our objective was to identify a way to quickly build a water budget for an ungauged watershed, using limited data, to determine its freshwater inflow contributions to an estuary. We developed and tested this method for Big Boggy Creek, which flows into East Matagorda Bay (EMB), Texas. Streamflow into and out of Big Boggy Creek was quantified at key upstream and downstream points. Over the study period, we found average monthly freshwater inflows of 1,897 megaliters (ML). Historic and predicted freshwater inflows over a longer time period were calculated using a data-driven model, based on our water budget. Historic monthly inflows for this model averaged 2,000 ML from 1953 to 2019 for Big Boggy Creek. Predicted inflows followed three climate scenarios outlined by the Intergovernmental Panel on Climate Change. Using these findings, we developed an inflow decision tool to assist resource managers in assessing future freshwater inflows into EMB. We show two inflow improvement actions for EMB that can be informed by using this tool—purchasing water from the local river authority and increasing the effective watershed. The approaches developed in this study can be applied to similarly ungauged watersheds to budget, model, and predict their freshwater inflow contributions to estuaries.

Tropical cyclones drive coastal ecosystem dynamics, and their frequency, intensity, and spatial distribution are predicted to shift with climate change. Patterns of resistance and resilience were synthesized for 4138 ecosystem time series from n = 26 storms occurring between 1985 and 2018 in the Northern Hemisphere to predict how coastal ecosystems will respond to future disturbance regimes. Data were grouped by ecosystems (fresh water, salt water, terrestrial, and wetland) and response categories (biogeochemistry, hydrography, mobile biota, sedentary fauna, and vascular plants). We observed a repeated pattern of trade-offs between resistance and resilience across analyses. These patterns are likely the outcomes of evolutionary adaptation, they conform to disturbance theories, and they indicate that consistent rules may govern ecosystem susceptibility to tropical cyclones.

Upstream agriculture and infrastructure development can greatly alter downstream hydrology, cutting off water sources and modifying connectivity that is critical for wetland survival. For tracts within the Anahuac National Wildlife Refuge (ANWR) located on the Texas Gulf Coast, our overall objective was to identify how much freshwater was needed to offset these processes. We sought to examine the historical trajectory of wetlands change, identify how to optimally route water through former agricultural canals, and make initial gross estimates of the volumetric water requirements. To prioritize specific restoration actions given the extremely flat topography of this sheet flow landscape, we used a combination of field survey by Unmanned Aerial Vehicles (UAVs), direct observation via airboats, Global Navigation Satellite System (GNSS) technologies, and remote assessment using aerial photography, LIDAR datasets, and Geographic Information Systems (GIS). We found that the optimal solution would minimize construction work and the quantity of water needed for purchase, while maximizing the inundation across the landscape. The unique combination of spatial technologies applied in this study provides a template for future work in similar sheet flow-fed landscapes affected by hydrologic disconnection and relative sea level rise.

Publicly available tidal predictions for coastlines are predominantly based on astronomical predictions. In shallow water basins, however, water levels can deviate from these predictions by a factor of two or more due to wind-induced fluctuations from non-regional storms. To model and correct these wind-induced tidal deviations, a two-stage empirical model was created: the Enhanced Tidal Model (ETM). For any given NOAA tide gauge location, this model first measured the wind-induced deviation based on a compiled dataset, and then adjusted the astronomical predictions into the future to create a 144-hour forecast. The ETM, when incorporating wind data, had only 76% of the error of NOAA astronomical tidal predictions (e.g. if NOAA had 1.0 ft. of error, ETM had only 0.76 ft. error from the observed water level). Certain ETM locations had approximately half (49%) as much prediction error as NOAA. With the improvement in tidal accuracy prediction, the ETM has the ability to significantly aid in navigation along with coastal flood prediction. We envision the ETM as a resource for industry and the public to make informed decisions that impact their livelihood.

The world's largest hydrocarbon disturbance occurred in the deserts and offshore waters of Kuwait during the Second Gulf War in 1990–1991. In this research, remote sensing (RS) and geographic information system (GIS) techniques were utilized to explore how native desert vegetation has recovered from hydrocarbon contamination after the Second Gulf War. By using RS techniques, change detection analysis was conducted to understand the changes about the coverage and extent of the total petroleum hydrocarbon (TPH) contamination and vegetation recovery. These changes were traced from 1991 until the hydrocarbon was no longer visible on the ground surface in 1998. GIS spatial analysis was conducted to determine the major ecosystem factors that influenced the vegetation recovery along with the removal of hydrocarbon disturbance. According to the results, autogenic recovery occurred at both sites within a few years and that desert native vegetation was found to have the ability to adapt and recover from hydrocarbon pollution. Native vegetation recovered across 31% of the TPH‐contaminated areas at Umm Gudair and 34% at Wadi Al Batin. The changes in TPH contamination were significantly correlated with the soil type, vegetation type, geological substrates, geomorphological features, and annual precipitation. The vegetation recovery of dominant desert communities in the study area was influenced by soil type, geomorphological feature, and TPH‐contaminated areas. Interestingly, the results showed that these desert communities can recover in areas contaminated by TPH at a higher rate than noncontaminated sites in the study area. Such a study can provide important inputs to the restoration and revegetation programs in arid landscapes.

China now accounts for over 2/3 of the world's production of marine-based seafood. Chinese mariculture has contributed to the stability of the global food supply, but millions of tons of excess feed and drugs are threatening the sustainability of the waters in which it is conducted. Over 26% of the excess nitrogen in China's waters is likely a result of shrimp production alone, worsening eutrophication and the resulting ‘red tide’ in China. While some Chinese operations require the destruction of carbon-rich wetlands, the sector as a whole can be considered a net CO2 sink at the immediate time of harvest; each year, Chinese mariculture extracts the same quantity of CO2 from the atmosphere as 5000 km2 of forest. Novel technical practices, improved management of the harvested products in the food versus industrial supply chain, optimized sea-use and land-use plans, and the encouragement of participatory decision-making by provincial entities offer some promise to ensure the sustainability of this global public resource – but the national Chinese government will have to step up to address the challenges.

Coastal wetland losses in China are globally-relevant issues, as formerly sequestered soil organic carbon is released as CO2 into the atmosphere. Wetland losses also reduce the primary production by plants that would otherwise bury carbon in the future. More than 50% of these ecosystems have been lost globally over the last half century, with this number approaching 58% in China. The negotiation of international accords such as the Paris Climate Agreement rely on the accurate assessment of ecosystem-held carbon quantities. Our objective was to provide the first national scale survey of coastal wetland-based carbon in China. The average soil organic carbon stock (Mg SOC ha−1) across all three types of ecosystems was 236.91, with an average of 344.67 for mangroves, 175.14 for seagrass, and 134.37 for salt marshes. The SOC stock was greatest at 30–60 cm of depth in the case of mangroves, as opposed to 0–20 cm of depth for salt marshes. In terms of the carbon content of the standing aboveground and belowground biomass (Mg C ha−1), mangroves contained by far the most with an average of 253.98 and 83.96, respectively. Carbon burial rates, or the annual flux of SOC into the soil column (Mg C ha−1 yr−1), were 2.26 ± 0.39 for mangroves, 1.38 ± 0.38 for seagrass, and 2.18 ± 0.24 for salt marshes. Through our work, we found a total of 48.12–123.95 Tg of C in China's coastal wetlands (down to 1 m of soil column depth), with an annual burial of 0.84 Tg yr−1. We estimate the average annual emissions of CO2 to be on the order of 6.83 Tg CO2 yr−1, due to ongoing and extensive wetland loss and conversion.

Coastal dunes are often the first and only line of physical defense for communities subjected to damaging storms and waves. Planting vegetation on them has been proposed as one way to increase their protective capacity, but it is unknown how dune plant architecture reduces erosion. We conducted wave flume and field experiments to address this question and found that dune plants primarily reduced erosion by attenuating wave swash and run up bores with their stems and leaves, while their roots initially enhanced erosion through uprooting. After excavation, the roots also attenuated waves and reduced erosion. We then sampled the biophysical attributes of a broad distribution of plants, and found that herbaceous non-Graminoid (non-grass) species that inhabited the lowest latitudes and most seaward zones had the most efficient structures for erosion reduction. Our results suggest that there is a fundamental tradeoff in the ability of dune plant species to respond to hydrodynamic versus Aeolian processes, based on the relative allocation of aboveground versus belowground biomass. Through the combination of flume experiments, field survey, and meta-analysis, our findings show that vegetation provides on average ∼1.6 factor of safety over bare sand across a wide range of latitudes in the northern hemisphere - translating into a reduction of wave run up erosion by approximately 40% for dunes.

Coastal erosion is a natural process, whose intensity and occurrence have increased due to natural and anthropogenic factors. To protect the coasts, the use of hard infrastructure is a widespread practice that can be effective, mostly at a local scale. However, recent evidence also shows that downstream erosion can be accelerated in adjacent zones. Because of this, natural barriers such as coastal dunes and their plant cover have gained attention, but there is a general lack of information about the role that different species (and combinations of species) play in coastal protection. The aim of this study was to explore if the functional richness of plant species helps reduce wave erosion on embryo coastal dunes. In a wave flume, we set up a 1:1 scale artificial dune covered with different combinations of plant species (Ipomoeae pes-caprae, Sesuvium portulacastrum, and Sporobolus virginicus) and exposed it to simulated “storm waves”. We found that erosion was reduced in dunes covered by plants, but such protection was species-specific and the effectiveness of protection varied over time. Ipomoea was the most effective specie for protection. Differences between species and combinations of species were associated with their physical attributes such as growth form and plant architecture. Although we found that there are species that offer little or no protection from hydrodynamic forces, they may still be important for coastal protection through their ability to build embryo dunes through eolian processes. Indeed, nature-based coastal protection is likely to be an effective alternative to engineered solutions at many sites, but the protection provided is species-specific.

The structural framework of the northern Gulf of Mexico coastal zone includes numerous growth fault systems. Neotectonic processes in coastal environments here have been shown to be important contributors to subsidence and relative sea-level rise, as well as having significant influences on sedimentary accretion processes. One active growth fault at East Matagorda Peninsula, Texas was subjected to detailed study to address the hypotheses that (1) this fault was present and active before the peak of regional hydrocarbon recovery in the mid-20th century, and that (2) slip along this fault has been episodic over the resolved period of record. To characterize the late Holocene behavior of this fault, three core transects were established normal to the surface fault trace, and stratigraphic analysis was conducted with the use of radiocarbon (14C) for chronological control. Correlation of time-equivalent stratigraphic boundaries reveals a maximum total late Holocene offset of 0.7 m. The Matagorda fault was in place long before the peak of regional oil and gas extraction, but experienced a late Holocene rejuvenation, initiated between 2500 and 1500 years BP. The kinematic behavior of the fault expressed as temporally and spatially variable measures of expanded stratigraphic thicknesses on the downthrown extent suggest that sediment loading from the transgressive Matagorda barrier complex may have contributed to this rejuvenation, and that slip along the fault persists to the present. Radiocarbon chronology also revealed clear differences in the magnitude of fault throw during the late Holocene, with maximum displacement (0.7 m) occurring at the southwestern-most transect and minimum throw at the northeastern-most transect (0.2 m).

Sea level rise and increased frequency of high-energy storms are contributing to the retreat of coastlines, impacting both natural features and coastal communities. “Soft solutions”, or natural alternatives to engineered structures, have gained popularity in beach erosion mitigation; however, wrack as a method of erosion prevention remains an understudied option. The objective of our study was to test if a globally-distributed macroalgae, Sargassum spp., could act as a natural solution to moderate coastal erosion. We used a flume and increasing volumes of sargassum to consider three erosional processes at specific locations of the cross-shore profile: wave formation offshore, scouring velocity in the swash zone, and erosion on embryonic dunes. As the quantity of sargassum increased, the measureable attributes of these processes were reduced in a strongly significant manner, with large amounts of sargassum linked to 12% wave attenuation, 46% scouring velocity reduction, and 103% dune erosion reduction. Even with the lightest covering of sargassum tested, embryonic dune erosion was reduced 6% when compared to the control. These results indicate sargassum, and likely many other types of wrack, are a viable resource to help mitigate daily beach erosion.

North American porcupines (Erethizon dorsatum) have expanded their range into central Texas and are now frequent users of caves as den sites. What remains unknown is how caves affect their home range, and their local habitat preferences. This information is important for management decisions on Joint Base San Antonio – Camp Bullis where novel and abundant porcupine scat in caves could jeopardize federally endangered cave-obligate arthropods by allowing for the invasion of less specialized terrestrial species. To better understand porcupine home range and habitat use at Camp Bullis, we trapped four porcupines at cave entrances and fitted them with GPS collars. The 95% home range averaged 71.3 ha for females and measured 420.6 ha for the male. The 50% core habitat averaged 55.4 ha for females and measured 7.4 ha for the male. Porcupines typically stayed near the den-cave trap site except when visiting more diverse mixed forest patches. At the landscape and point levels, individuals selected for forested cover and avoided open areas. At the home range level, individuals selected for bare ground and roads, which were likely used to get from the cave den site to feed at mixed forest patches. Typically solitary, individuals in this study tolerated sharing a cave. Because of the small sample size and single sampling location, this study represents a pilot study and additional research is needed to establish concrete conclusions. Should cave managers need to limit the cave use by porcupines, a cave gate, exclosure, or reduction of forested cover would make caves less desirable.

We examined total mercury (Hg) distributions in sediments from the Penobscot River and estuary, Maine, a site of extensive Hg releases from HoltraChem (1967–2000). Our objectives were to quantify: (1) bottom sediment Hg inventories (upper ~ 1 m; 50–100 y); (2) sediment accumulation rates; and (3) contemporary Hg fluxes to bottom sediments; by sampling the Penobscot River (PBR), Mendall Marsh (MM), the Orland River (OR) and the Penobscot estuary (ES). Hg was rapidly distributed here, and the cumulative total (9.28 metric tons) associated with sediments system-wide was within the range released (6–12 metric tons). Evidence of sediment/Hg remobilization was observed in cores primarily from the PBR, and to a lesser extent the ES, whereas cores from MM, most of the OR, the ES, and half from the PBR exhibited sharp peaks in Hg concentrations at depth, followed by gradual decreases towards the surface. Based on background PBR sediment Hg concentrations (100 ng g− 1), “elevated” (300 ng g− 1), or “highly elevated” (600 ng g− 1) Hg concentrations in sediments, and resulting inventories, we assessed impact levels (“elevated” ≥ 270, or “highly elevated” ≥ 540 mg m− 2). 71% of PBR stations had “elevated”, and 29% had “highly elevated” Hg inventories; 45% of MM stations had “elevated”, and 27% had “highly elevated” inventories; 80% of OR stations had “elevated” inventories only; and 17% of ES stations had “elevated” inventories only. Most “highly elevated” stations were located within 8 km of HoltraChem, in MM, in the PBR, and in the OR. Near-surface sediments in the OR, PBR and MM were all “highly elevated”, while those in the ES were “elevated”, on average. Mean Hg fluxes to bottom sediments were greatest in the OR (554), followed by the PBR (469), then MM (452), and finally the ES (204 ng cm− 2 y− 1).

Carbon cycling in the coastal zone affects global carbon budgets and is critical for understanding the urgent issues of hypoxia, acidification, and tidal wetland loss. However, there are no regional carbon budgets spanning the three main ecosystems in coastal waters: tidal wetlands, estuaries, and shelf waters. Here, we construct such a budget for Eastern North America using historical data, empirical models, remote-sensing algorithms, and process-based models. Considering the net fluxes of total carbon at the domain boundaries, 59 ± 12% (± 2 standard errors) of the carbon entering is from rivers and 41 ± 12% is from the atmosphere, while 80 ± 9% of the carbon leaving is exported to the open ocean and 20 ± 9% is buried. Net lateral carbon transfers between the three main ecosystem types are comparable to fluxes at the domain boundaries. Each ecosystem type contributes substantially to exchange with the atmosphere, with CO2 uptake split evenly between tidal wetlands and shelf waters, and estuarine CO2 outgassing offsetting half of the uptake. Similarly, burial is about equal in tidal wetlands and shelf waters, while estuaries play a smaller but still substantial role. The importance of tidal wetlands and estuaries in the overall budget is remarkable given that they respectively make up only 2.4 and 8.9% of the study domain area. This study shows that coastal carbon budgets should explicitly include tidal wetlands, estuaries, shelf waters and the linkages between them; ignoring any of them may produce a biased picture of coastal carbon cycling.

Sigren, J.M.; Figlus, J.; Highfield, W.; Feagin, R.A., and Armitage, A.R., 2018. The effects of coastal dune volume and vegetation on storm-induced property damage: Analysis from Hurricane Ike. In response to numerous recent high-profile cases of tropical storm and hurricane damage to coastal communities, there has been increasing attention on the storm protection services provided by coastal ecosystems. However, substantial knowledge gaps exist regarding the quantitative economic benefits of such services, particularly for coastal vegetated dune ecosystems. A novel geographic information system (GIS)-based technique for delineating, quantifying, and relating coastal dune volume, vegetation area, and geographic and built-environment covariates to sustained property damage was used for the upper Texas coast following Hurricane Ike in 2008. The multivariate regression analysis contained more than 1000 homes spanning both sides of the storm's path. Dune volume and vegetation were both significantly ...

Vegetation is an important feature of coastal dunes and is often managed to stabilize restored dunes and provide coastal protection. Despite a high investment in planting and management efforts, little is known about how vegetation is affected by wind and wave run-up. The objectives of this study were to 1) investigate the lift forces and drag moments experienced by coastal dune vegetation from wind and wave run-up and 2) relate them to flow properties and plant morphology. Panicum amarum, Ammophila breviligulata, A. arenaria and Cakile maritima were subjected to laboratory wind and wave run-up conditions. Measurements were taken of fluid velocity, run-up depth, Reynolds number, and plant biophysical properties. The plant lift and drag responses were recorded with the use of a novel sensor designed to address the complexities induced by the flexibility and morphology of real vegetation under varying conditions. Regression analysis was used to describe the relationships between plant response and plant structure and flow properties. Experiments showed that wind induced a constant lift force and drag moment on plants over time, whereas run-up induced plant response was time-dependent. Plant height (R2 = 0.64, p

Huff, T.P. and Feagin, R.A., 2017. Restoring tidal equilibrium: Removing a hydrologic barrier and lowering salinity at the Magnolia Inlet, Texas. In: Martinez, M.L.; Taramelli, A., and Silva, R. (eds.), Coastal Resilience: Exploring the Many Challenges from Different Viewpoints. Journal of Coastal Research, Special Issue No. 77, pp. 97–103. Coconut Creek (Florida), ISSN 0749-0208. A large area of salt marsh located between Magnolia Beach and Indianola, Texas had rapidly degraded over the last few decades due to a hydrologic barrier. Sediment and shell debris in the main tidal channel had greatly reduced flow between interior sections of marsh and the adjacent open bay, blocking all hydrologic exchange except for extreme tides. As a result, the impounded waters were often hypersaline, the vegetation was dying, and access to habitat was restricted for aquatic nekton. Our overall objective was to identify the cross section of debris that would need to be removed from the channel in order to restore ...

Huff, T.P. and Feagin, R.A., 2017. Hydrological barrier as a cause of salt marsh loss. In: Martinez, M.L.; Taramelli, A., and Silva, R. (eds.), Coastal Resilience: Exploring the Many Challenges from Different Viewpoints. Journal of Coastal Research, Special Issue No. 77, pp. 88–96. Coconut Creek (Florida), ISSN 0749-0208. The Magic Ridge Marsh located along Magnolia Beach, Texas has rapidly degraded over the last few decades. This marsh is of great importance to wildlife and dependent recreational pursuits such as bird watching at the Magic Ridge Sanctuary and fishing in the marshes and adjacent bay. In this study, we decided to focus on the shell debris pile as aerial imagery, along with local knowledge, indicated that this was the point of hydrologic disturbance. In order to restore this ecosystem, the alterations to the hydrology had to be understood and thus the multi-stage approach was chosen to single out the environmental factors that influence the marsh. Land cover analyses were conducted...

Knowledge of meso-mammal cave use is essential for natural resource managers, particularly in the management of endangered cave invertebrates. Scat left by meso-mammals represents significant nutrient inputs into the oligotrophic cave environment which can disrupt the invertebrate species composition and ecology. Since little is known about what constitutes typical timing or frequency of meso-mammal visitation, current management practices are largely speculative. Central Texas caves were historically associated with raccoons Procyon lotor, but with the loss of large predators and encroachment of woody vegetation, the now naturalized North American porcupine Erethizon dorsatum has become an established part of the local ecosystems whose effect on cave biology remains unknown. Our objective with this study was to quantify meso-mammal cave use according to seasons, time of day, weather conditions, as well ecological and physical cave characteristics. We monitored 30 caves by placing trail cameras at cave entrances for one year on Joint Base San Antonio-Camp Bullis military base just north of San Antonio, Texas. North American porcupines, raccoons, and Virginia opossums Didelphis virginiana were the three most commonly photographed meso-mammals (>87%). All meso-mammal groups showed significantly different cave use according to season, weather, and cave characteristics. Data suggested most meso-mammals were using caves for denning while raccoons and Virginia opossums also were feeding on resident invertebrate and rodent populations. In particular, Virginia opossum and raccoon, both potential predators of endangered species, showed greater use of caves containing endangered species. The results from our study represent an initial step in understanding meso-mammal cave use in central Texas.

Coastal wetlands are a crucial buffer zone between land and sea but lateral erosion threatens their long-term sustainability. Better understanding of the forces leading to lateral marsh retreat will benefit the assessment of management options applied to mitigate the erosion. Terrestrial Laser Scanning (TLS), Light Detection and Ranging (lidar), and associated technologies are increasingly being used to assess this erosion. The central objective of this study was to identify a methodology for measuring marsh edge erosion with a TLS and correlate that erosion with exposed roots and incident wave energy. We quantified edge erosion across multiple temporal and spatial scales using a TLS, showing greater than one meter of lateral erosion over a 318-day period. We then evaluated the relationships between the erosion and incident wave energy along with erosion and vegetation roots. Wave height and erosion was strongly related (r2 = 0.99), while vegetation roots did not show an apparent effect. We discuss the challenges that arise from using TLS equipment, TLS data sets, and the use of voxels to measure marsh edge erosion.

During sea level rise, salt marshes transgress inland invading low-lying forests, agricultural fields, and suburban areas. This transgression is a complex process regulated by infrequent storms that flood upland ecosystems increasing soil salinity. As a result upland vegetation is replaced by halophyte marsh plants. Here we present a review of the main processes and feedbacks regulating the transition from upland ecosystems to salt marshes. The goal is to provide a process-based framework that enables the development of quantitative models for the dynamics of the marsh-upland boundary. Particular emphasis is given to the concept of ecological ratchet, combining the press disturbance of sea level rise with the pulse disturbance of storms.

A storm passage results in acute beach erosion and loss of immense amounts of sand from the affected coastlines. Erosion may reach sand dunes which act as dynamic protective barriers, mitigating the impact of larger waves and storm surge. A dune starts being damaged by a storm when the wave runup is still confined in the swash zone; the region of beach foreshore which is intermittently influenced by the wave motion. Data acquisition in the highly dynamic zone is challenging during catastrophic weather conditions. Therefore, the fate of sand and the subsequent morphological change is difficult to predict. A near-prototype experiment was conducted to provide further insights in the physical mechanisms that result in dune erosion.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/pZMDwRrpg8Y

Potential changes in future climate in the Texas Plains region were investigated in the context of agriculture by analyzing three climate model projections under the A2 climate scenario (medium–high emission scenario). Spatially downscaled historic (1971–2000) and future (2041–2070) climate datasets (rainfall and temperature) were downloaded from the North American Regional Climate Change Assessment Program (NARCCAP). Climate variables predicted by three regional climate models (RCMs) namely the Regional Climate Model Version3–Geophysical Fluid Dynamics Laboratory (RCM3-GFDL), Regional Climate Model Version3–Third Generation Coupled Global Climate Model (RCM3-CGCM3), and Canadian Regional Climate Model–Community Climate System Model (CRCM-CCSM) were evaluated in this study. Gaussian and Gamma distribution mapping techniques were employed to remove the bias in temperature and rainfall data, respectively. Both the minimum and maximum temperatures across the study region in the future showed an upward trend, with the temperatures increasing in the range of 1.9 to 2.9 °C and 2.0 to 3.2 °C, respectively. All three climate models predicted a decline in rainfall within a range of 30 to 127 mm in majority of counties across the study region. In addition, they predicted an increase in the intensity of extreme rainfall events in the future. The frost-free season as predicted by the three models showed an increase by 2.6–3.4 weeks across the region, and the number of frost days declined by 17.9 to 30 %. Overall, these projections indicate considerable changes to the climate in the Texas Plains region in the future, and these changes could potentially impact agriculture in this region.

Human encroachment on the coasts is extensive and expected to increase over the coming decades. This proximity to the sea is coupled with potentially more frequent strong tropical cyclones and eustatic sea level rise, and thus human life, property and infrastructure are threatened. In this scenario, it is vital to find the means to maintain or increase the resilience and resistance of coastal zones. As an alternative to engineering solutions, ecosystem-based coastal defence strategies have been recommended as better and more sustainable solutions, although it has not been clearly demonstrated that they really work. In 24 wave flume experiments, we studied the effects of four densities of vegetation cover (none, low, medium, high) on the movement of sediment along two beach–dune profiles (with and without a berm), under three storm conditions (mild, moderate and intense). Erosion regimes of collision and overwash were observed in the dune profiles with a berm, whereas swash and overwash regimes were observed when no berm was present. In the profiles with a collision regime, vegetation decreased the amount of erosion. For both profiles, in the tests with the largest wave conditions, vegetation prevented overwash and thereby erosion of the landward side of the dune. Erosion of the dune face was reduced by vegetation, particularly with a strong storm, when Iribarren numbers were greater. In summary, vegetation reduced net erosion on the dune face, regardless of the wave conditions, the morphology of the beach–dune profile, or the mode of erosion.

Coastal dunes can provide protection from flooding during extreme weather events. As such, consideration should be given to strengthening the protective mechanisms of dunes. Vegetation has recently been seen as an important factor influencing erosion processes on dunes. Another means of dune reinforcement is the installation of internal structures within dune systems. The purpose of this work is to investigate the potential utility of both vegetation and an internal rocky structure as reinforcing factors on dunes, and explain how they differentially dissipate wave energy and influence the morphodynamic response of the dune profile. This work consists of a series of experiments on dune profiles, with and without an inner rocky structure, and with two different distributions of live Ipomoea pes-caprae plants of the same density, under storm conditions. The results showed that when vegetation was at forward positions on the dune, it decreased run-up, increased reflected energy and transferred it to low frequency bands, and reduced the eroded volume on the exposed dune face. When the vegetation was placed on the leeside of the dune, it retarded and prevented overwash, but not as efficiently as the internal rocky structure did. In summary, plants are better to dissipate waves and provide protection during the initial swash and collision stages of a storm, while a rock structure is better to prevent overwash and dune destruction during the final stages. While it is possible to use both means together, for maximum protection, dune managers should weigh the financial and ecological costs according to each unique project location.

Martinez, M.L.; Silva, R.; Lopez-Portillo, J.; Feagin, R.A., and Martinez, E. 2020. Coastal ecosystems as an ecological membrane. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 97-101. Coconut Creek (Florida), ISSN 0749-0208.A membrane is a continuous layer that separates the interior of a cell from its surrounding cells or environment. It is selectively permeable because it regulates the transport of water, ions, and organic compounds. Its primary function is protection. Relatively analogous to a cell membrane, coastal ecosystems can be considered as an ecological membrane because they regulate the bidirectional transport of materials between the terrestrial and marine ecosystems and provide protection. The components of the ecological membrane include coral reefs, seagrass beds, beaches, coastal dunes, mangroves, marshes, and coastal lagoons. The selective permeability depends on the ecosystem. Pollutants and heavy metals, carbon, and nutrients are captured by the biota and sediments of mangroves, seagrasses, and marshes, and thus decrease the impact of pollution from the watershed to the ocean. Seagrasses, mangroves, beaches, and coastal dunes mitigate the inland effects of storms and hurricanes by reducing wave energy during storm surges. We examine how coastal ecosystems act as ecological membranes by looking at the evidence available. We focus on the flow of two features: heavy metals towards the ocean and waves towards the continent. We use field data to show how heavy metals are trapped by mangroves and coastal lagoons, which are porous ports of entry and exit. Also, wave flume experiments demonstrate how wave erosion is mitigated by vegetated coastal dunes, which act as protective barriers. Management schemes can be improved if coastal ecosystems are considered as components of a dynamic ecological membrane.

Scat of meso-mammals provides nutrients to cave-obligate species. If there are too few nutrient inputs, cave-obligate species have no resources, but too much and caves are invaded by terrestrial species. Our goal for this project was to determine what combination of variables most influence meso-mammal cave use by building a multinomial regression model using data collected from cave entrances in central Texas. Variables of importance in our model relate to cave accessibility, including the raccoons' (Procyon lotor) and Virginia opossums' (Didelphis virginiana) greater dexterity, and the added bulk from the North American porcupine's (Erethizon dorsatum) quills. Our model can be used to predict and manage meso-mammal cave use in central Texas. This will be especially useful in this region because North American porcupine have only recently expanded their range into central Texas and their prolific nutrient inputs, previously absent from the ecosystem, could endanger cave-obligate species.

Smooth cordgrass (Spartina alterniflora) was introduced to China in December 1979 to buffer against tides and to accelerate coastal wetland accretion. Since then, its propagation and natural dispersal have allowed this exotic plant to rapidly expand throughout coastal China with generally negative ecological effects. In 2003 S. alterniflora was labeled as an invasive plant in China, and it now covers ~50,000 ha. In this review, we first summarize the mechanisms of spread and spatial distribution of S. alterniflora, and how its physiological characteristics and strong adaptability to the available niche space in China's wetlands have enabled its spread and competition with native plants. Then we review the effects of S. alterniflora on ecosystem function in terms of habitat conversion and the alteration of biodiversity, soil carbon flux and sequestration, and various processes of nutrient regulation. We conclude that we need a long-term and context-dependent perspective, in order to maximize the benefits and minimize the costs of S. alterniflora within each of China's unique provinces.

This chapter discusses the fate of allochthonous particulate organic carbon (C) (POC), either sorbed organic C (OC) onto clay particles, as detrital organic particles, and dissolved OC (DOC) in modern coastal blue C ecosystem (BCE). BCEs, or the C stored in coastal systems such as mangroves, salt marshes, and seagrass meadows, form some of the largest global C reserves, and are distributed throughout numerous latitudinal zones. Coastal tidal marshes are largely found in temperate zones but do extend into the tropics, mangroves are confined to tropical and sub-tropical regions due to their freeze intolerance, and seagrasses are broadly distributed from cold polar waters to the tropics. The fate of allochthonous blue C released into coastal waters and the open sea or sequestered in the coastal BCEs is highly specific to the coastal margin setting. Coastal aqueous POC and DOC forms constitute the major pool of organic matter providing C and energy to heterotrophs in estuaries.

Developing a site history and ecological site description is one of the critical steps in restoration planning for arid landscapes. This study focuses on Umm Nigga, Northeast of Kuwait, which was damaged by various human activities. The northern portion of Umm Nigga falls within the boundaries of the demilitarized zone (DMZ) adjacent to Iraq, and was fenced off to restrict public access since 1994. The central objective of this project was to use remote sensing, field assessment, and Geographical Information System (GIS) spatial data to develop a site history for restoration planning of Umm Nigga. Field observation and GIS analysis indicated that the landscape could be divided into three units along a gradient ranging from the coast to inland locations, based on geology, soil properties, and dominant vegetation. Reference sites in the DMZ were also matched for each unit. Remote sensing was used to compare vegetation cover between damaged and reference sites at selected units. Results showed that vegetation cover increased in the unfenced damaged site after the 1991 Gulf War from 2% in 1988 to 37% in 1998, but then it decreased to 23% in 2013. In the DMZ reference site, the vegetation cover also increased from 0% in 1988 to 40% in 1998, but it continued increasing through 2013 to 64%. We conclude that overgrazing and destructive camping are the major source of disturbance in the damaged areas.

Coastlines have traditionally been engineered to maintain structural stability and to protect property from storm-related damage, but their ability to endure will be challenged over the next century. The use of vegetation to reduce erosion on ocean-facing mainland and barrier island shorelines – including the sand dunes and beaches on these islands – could be part of a more flexible strategy. Although there is growing enthusiasm for using vegetation for this purpose, empirical data supporting this approach are lacking. Here, we identify the potential roles of vegetation in coastal protection, including the capture of sediment, ecological succession, and the building of islands, dunes, and beaches; the development of wave-resistant soils by increasing effective grain size and sedimentary cohesion; the ability of aboveground architecture to attenuate waves and impede through-flow; the capability of roots to bind sediments subjected to wave action; and the alteration of coastline resiliency by plant structur...