Coastal Sand Dunes Research Articles

Principles of cross congruence do not apply in naturally disturbed dune slack habitats: Implications for conservation monitoring

Cross congruence, where diversity or composition of multiple species follow similar patterns, underlies the use of indicator species in conservation practice. However, there are circumstances in which cross congruence has been shown to break down, for example after disturbance events. If cross congruence does not occur in habitats which experience natural disturbance, then conservation measures based on indicator species may yield misleading results. We assessed the degree of cross congruence among three biological taxa in dune slacks, which are temporary ponds found in coastal sand dunes. We also investigated the efficacy of a national monitoring assessment based on a single taxonomic group, plants, to predict the diversity and composition of two other taxonomic groups: snails and water beetles. We found no evidence of cross congruence among these three groups and the plant-based monitoring system did not predict the composition or diversity of snails or water beetles. The potential for dune slacks to support species of conservation interest was demonstrated here as eight snail species and two water beetle species listed as Near threatened or Vulnerable on the Irish Red Lists were found within the 24 sites surveyed, and the Irish populations of two of these are of international significance (Vertigo angustior, Leiostyla anglica). Some of these species of conservation interest were found in dune slacks which were of poor conservation status according to the monitoring methodology applied. Our results show that indicator species drawn from a single taxonomic group are not adequate to monitor the general habitat condition of dune slacks. Dune slacks are among many habitats of conservation interest which experience natural disturbance, and this research has implications for conservation practice in other habitats such as seasonal wetlands and fire-dependent habitats.

Numerical Simulation and Large-Scale Physical Modelling of Coastal Sand Dune Erosion

Do, K.; Shin, S.; Cox, D., and Yoo, J., 2018. An international comparison of drowning in South Korea. In: Shim, J.- S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 196–200. Coconut Creek (Florida), ISSN 0749-0208.Coastal sand dune system is important in the nearshore environment for sand supply, ecosystem, and hazard mitigation. In this study, a process-based morphological model was performed and the results were compared with large-scale laboratory experimental data. Two-dimensional large-scale laboratory experiments were conducted with 1:6 geometric scale in the large wave flume (104m (L) × 3.7 m (W) × 4.6 m (D)) of the Hinsdale Wave Research Laboratory at Oregon State University (Maddux et al, 2006). Several different wave conditions were used with different water levels in this experiment including pre-storm, storm, and post storm based on random wave time series by using TMA spectrum. The data set included cross-shore Wave heights, fluid velocities, and the profile changes of the beach and dune. The process based model, XBeach (Roelvink et al., 2009) was used to simulate the nearshore hydrodynamics and bed level change during storm wave condition. Several semi-empirical parameters were used in the XBeach model to predict morphodynamic process (Roelvink et al., 2009) and recently the updated parameters (WTI settings) were suggested based on the results of field observations. The present study ran the XBeach model by using both default and WTI settings and compared with the results from the experiments. The results showed that the model results with WTI settings showed good agreement with the measured beach profile while the model results with default settings over-predicted the offshore sediment transport and dune erosion. Especially, the wave skewness (facSk) and asymmetry (facAs) gave the highest contribution to predict dune erosion.

Full-Waveform LiDAR Pixel Analysis for Low-Growing Vegetation Mapping of Coastal Foredunes in Western France

The monitoring of coastal sand dunes requires regular high-resolution aerial photography along hundreds of kilometers of coastal strips. Light detection and ranging (LiDAR) is now the most widely used method for detailed topographic and vegetation studies. The aim of this work is to show how the full-waveform shapes returned from single or multiple targets can carry information relating to low-vegetation cover and ground roughness of dunes. This work focuses on marram grass, widely involved in the development of mobile dunes. Low-growing plants often exhibit identical pigmentary composition and can only be distinguished by the height of their foliage, which modifies the shape of the LiDAR waveform around the main returns at the top of the foliage. We show that ray tracing of full LiDAR waveforms on the regular grid of pixels of hyperspectral images, acquired synchronously, can resolve the confusion between low-vegetation gradients and bare sand by analyzing the waveform damping induced by cumulating microdiffusion on foliage height, but also with glint effects on the surface roughness of compact materials. Analysis of successive shorelines of wet to dry sand, sand to pioneer couch grass, and couch grass to consolidating marram grass can thereby be conducted routinely.

Variation in home‐field advantage and ability in leaf litter decomposition across successional gradients

Abstract It is increasingly recognized that interactions between plants and soil (a)biotic conditions can influence local decomposition processes. For example, decomposer communities may become specialized in breaking down litter of plant species that they are associated with, resulting in accelerated decomposition, known as “home‐field advantage” (HFA). Also, soils can vary inherently in their capacity to degrade organic compounds, known as “ability.” However, we have a poor understanding how environmental conditions drive the occurrence of HFA and ability. Here, we studied how HFA and ability change across three types of successional gradients: coastal sand dunes (primary succession), inland drift sands (primary succession) and ex‐arable fields (secondary succession). Across these gradients, litter quality (i.e. nutrient, carbon and lignin contents) increases with successional time for coastal dunes and decreases for the other two gradients. We performed a 12‐months reciprocal litter transplant experiment under greenhouse conditions using soils and litters collected from early‐, mid‐ and late‐successional stages of each gradient. We found that HFA and ability did not consistently shift with successional stage for all gradients, but were instead specific for each type of successional gradient. In coastal dunes, HFA was positive for early‐successional litter, in drift, sands it was negative for mid‐successional litter, and for ex‐arable fields, HFA increased with successional time. Ability of decomposer communities was highest in mid‐successional stages for coastal dunes and drift sands, but for ex‐arable fields, ability decreased throughout with successional time. High HFA was related to high litter C content and soil and organic matter content in soils and to low litter and soil nutrient concentrations. Ability did not consistently occur in successional stages with high or low litter quality. Synthesis. Our findings show that specific environmental conditions, such as changes in litter or soil quality, along environmental gradients can shape the influence of HFA and ability on decomposition. In sites with strong HFA or ability, interactions between plants, litter and decomposer communities will be important drivers of nutrient cycling and hence have the potential to feedback to plant growth. A plain language summary is available for this article.

Effects of row deep tillage for the growth base formed by piling up soil in damp lowlands behind coastal sand dunes to construct coastal disaster prevention forest belts on the Kujukuri coastline, Japan

ABSTRACT To successfully afforest coastal forest belts ensuring high disaster prevention, growth bases for them have been constructed by piling up soil in the low wetlands along the Kujukuri coastline. Ground surfaces in such bases are often covered with water because of soil compaction, leaving them susceptible to stagnant water. Water stagnation in soil is problematic, potentially interfering with afforesting coastal forests. Therefore, row deep tillage was conducted for parts of growth bases to combat the poor physical properties of the existing soil. Here, we surveyed soil profiles and measured vertical soil hardness distribution in two forest stands with piling up soil to evaluate the effectiveness of tillage for man-made soil. Soil hardness measurements indicated that the vertical areas with ‘soft’ and ‘hard/consolidated’ soil alternately appeared in growth base profiles. Generally, soil of the dense and very hard layers was apt to be formed by strong compaction of the filled-up soil because of heavy machinery usage during growth base preparation. Such dense and hard soils in the untilled areas of the profiles were also observed in this study. By contrast, it was confirmed that row deep tillage drastically improved soil physical properties, i.e., decreased hardness and increased water permeability, because the sequential hardened subsoil layers were well-broken-up. Moreover, it was observed many thick and large roots penetrated deeper layers with deep tillage areas. These results suggest that row deep tillage of hardened soil is quite effective at securing the areas and providing the physical conditions for deeply penetrated roots into deeper soils, which increases healthy root development. They show the effects of soil hardness reduction and water permeability improvement have been maintained for two decades, at least, after construction. These findings will be useful for alleviating some problems of soil compaction, water stagnation, and tree-growth hindrance that have been encountered on afforestation sites with man-made soil.

Variabilidade temporal do perfil de dunas na Praia do Cassino, RS, com auxílio de videomonitoramento Argus

A dinâmica sedimentar em dunas costeiras é um processo complexo que exige a análise de vários fatores em diferentes escalas temporais. A análise de um banco de dados morfológicos sequenciais de três anos, realizados em um setor de dunas da praia do Cassino, localizada ao sul do Rio Grande do Sul, Brasil (RS), permitiu identificar a evolução espaço-temporal do perfil de dunas, que apresentou um comportamento predominantemente acrescional médio de 14,86 m3 /m por ano. Dados de ventos e Índice de Oscilação Niño (ION) mostram que esses componentes foram os principais agentes modeladores durante esse período. As técnicas de processamento digital de imagens associadas ao sistema Argus permitiram verificar o aumento da densidade vegetacionalna região que juntamente com os fatores físicos observados contribuíram para o aumento de volume de areia dasdunas costeiras.

An allometric analysis of sexual dimorphism in Ctenomys australis: integrating classic morphometry and functional performance in vivo

The South American rodents of the genus Ctenomys (Rodentia, Hystricognathi), which use both forelimbs and incisors to dig, show strong, specialized morphological adaptations to living in the underground niche. In these rodents, the effectiveness of a bite − in this case the potential to inflict physical damage − mostly depends on the strength of the incisors (e.g. bending and torsion stresses) and the power of the masseteric muscle of the jaw. Ctenomys australis (the sand dune tuco-tuco) is a highly territorial subterranean rodent that builds large and exclusive burrow systems in coastal sand dunes found continuously along the Atlantic coast of the Buenos Aires province, Argentina. Incisors in this species are used both in agonistic encounters among congeners (i.e. reproductive or territorial intentions) as well as to dig and increase the size of their burrows daily (e.g. acquisition of plant material as food resources). We first characterized sexual dimorphism in cranial traits involved in aggressive interactions between males, analyzing ontogenetic trajectories of both sexes. We also analyzed some remarkable attributes of sexual dimorphism in subadult and adult individuals, the bending and torsion stresses and the bite performance in vivo, hypothesizing that males are able to apply comparatively stronger bite forces at their incisor tips than females, concordant with a broader mandible for the insertion of a powerful adductor musculature. Bite forces were measured in vivo in wild animals of both sexes using a strain gauge load cell force transducer. These individuals were also used to estimate the incisor area (CA), the 2nd moment of inertia of the incisors (I, or the bending strength to external forces), and the torsional strength of the incisor (J), all traits involved in the production of the force that can be withstood at the incisor tips. Ontogeny explained some sexual differences in the cranial traits of adults, expressed as (i) morphological changes related to body size variation, and (ii) morphological changes associated with differences in the slope of ontogenetic trajectories (regardless of body size variation). Recordings of in vivo bite forces were significantly higher in adult males than in females. These differences in bite forces were not associated with the sex itself, but the sexual dimorphism in body size. Although males did not show significantly higher allometric coefficients for I, J and CA than females, males still showed a strong sexual dimorphism in these traits due to body size variation. On the other hand, measurements of mandibular width – an estimator of the relative size of masseteric muscles – in vivo showed strong differences between sexes, suggesting higher force performance at the incisor tips for males. Overall, we observed that many attributes related to bite performance might have been molded by sexual selection, which implies differences in allometric coefficients from some morphological traits throughout ontogeny.

Survey of Formicidae Attracted to Protein Baits on Georgia's Barrier Island Dunes

Although insects have been identified as valuable bioindicator species, insect diversity in coastal sand dunes is understudied. Our study presents the first survey focused on Georgia's barrier island ant assemblage. We surveyed the primary and secondary dunes of Cumberland, Little St. Simons, and Sapelo islands in the summers of 2016 and 2017 using protein baits to recruit scavenging ants that forage on dunes and beaches. We placed 4863 baits over the 2 sampling seasons; 2458 recruited ants. We documented 29 ant species, including 3 new records for the state: Dorymyrmex reginicula, Pheidole navigans, and Solenopsis globularia. Our survey provides a baseline for future projects to evaluate disturbance and ecosystem health on Georgia's barrier islands.

Seasonal dynamics of leaf and litter stoichiometry of different tree species in a coastal sand dune of southern subtropical china

Seasonal dynamics of leaf and litter stoichiometry of different tree species in a coastal sand dune of southern subtropical china

Effects of forest cover types and environmental factors on soil respiration dynamics in a coastal sand dune of subtropical China

Trees on sand dunes are more sensitive to environmental changes because sandy soils have extremely low water holding capacity and nutrient availability. We investigated the dynamics of soil respiration (R s) for secondary natural Litsea forest and plantations of casuarina, pine, acacia and eucalyptus. Results show that significant diurnal variations of R s occurred in autumn for the eucalyptus species and in summer for the pine species, with higher mean soil respiration at night. However, significant seasonal variations of R s were found in all five forest stands. R s changed exponentially with soil temperatures at the 10-cm depth; the models explain 43.3–77.0% of R s variations. Positive relationships between seasonal R s and soil moisture varied with stands. The correlations were significant only in the secondary forest, and the eucalyptus and pine plantations. The temperature sensitivity parameter (Q 10 value) of R s ranged from 1.64 in casuarina plantation to 2.32 the in secondary forest; annual R s was highest in the secondary forest and lowest in the pine plantation. The results indicate that soil temperatures and moisture are the primary environmental controls of soil respiration and mainly act through a direct influence on roots and microbial activity. Differences in root biomass, quality of litter, and soil properties (pH, total N, available P, and exchangeable Mg) were also significant factors.

Behavioral compensation buffers body temperatures of two Liolaemus lizards under contrasting environments from the temperate Pampas: a Bogert effect?

Postural adjustments and microhabitat selection are two behavioral mechanisms that lizards extensively use to regulate their body temperatures. The Bogert effect occurs when behavioral thermoregulation buffers potential changes in body temperatures of congeneric organisms due to environmental variation, in turn precluding physiological evolution. We compared field body temperatures (Tb) and behavioral thermoregulation traits between two Liolaemus lizards: the saxicolous Liolaemus tandiliensis and the arenicolous Liolaemus wiegmannii. These species are spatially segregated in two thermally contrasting environments from the SE of the temperate Pampas of Argentina. During summer, the mean operative temperature (Te) of the coastal sand dunes occupied by L. wiegmannii was 9 ºC higher than that of the Tandilia mountains inhabited by L. tandiliensis. Despite the contrasting thermal conditions of both habitats, the mean Tb of L. tandiliensis (34.72 °C) was similar to that of L. wiegmannii (35.01 °C). The behavioral thermoregulation mechanisms varied considerably between both species. Liolaemus tandiliensis combined static body posture with displacements towards sunlit areas. In contrast, L. wiegmannii combined elevated and prostrated body postures with movements towards full and filtered sun patches. Environmental gradients offer diverse challenges impelling lizards to find different behavioral thermoregulation adaptations in order to partially cope with environmental constraints. This occurs in many species of Liolaemus that are thermoregulatory efficient despite of the climatic adversities. In this study, two species of Liolaemus used different postural and microhabitat path-selection strategies according to climate, allowing them to buffer changes in Tb, thus suggesting that the Bogert effect may be occurring in these two species.

Can sand dunes be used to study historic storm events?

AbstractKnowing the long‐term frequency of high magnitude storm events that cause coastal inundation is critical for present coastal management, especially in the context of rising sea levels and potentially increasing frequency and severity of storm events. Coastal sand dunes may provide a sedimentary archive of past storm events from which long‐term frequencies of large storms can be reconstructed. This study uses novel portable optically stimulated luminescence (POSL) profiles from coastal dunes to reconstruct the sedimentary archive of storm and surge activity for Norfolk, UK. Application of POSL profiling with supporting luminescence ages and particle size analysis to coastal dunes provides not only information of dunefield evolution but also on past coastal storms. In this study, seven storm events, two major, were identified from the dune archive spanning the last 140 years. These appear to correspond to historical reports of major storm surges. Dunes appear to be only recording (at least at the sampling resolution used here) the highest storm levels that were associated with significant flooding. As such the approach seems to hold promise to obtain a better understanding of the frequency of large storms by extending the dune archive records further back to times when documentation of storm surges was sparse. © 2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.

SOIL SICKNESS AND NEGATIVE PLANT-SOIL FEEDBACK: A REAPPRAISAL OF HYPOTHESES

Soil sickness (SS) is the rise of negative conditions for plant vegetative and reproductive performances induced into the soil by the plant itself. In natural ecosystems, plant ecologists refer to SS as negative plant-soil feedback (NPSF). Scope of this review is to provide an updated picture of the current SS understanding by an explicit comparison between agroecosystems and natural plant communities. By an extensive analysis of literature we found that SS is pervasive in agro-ecosystems, occurring in 111 cultivated plants belonging to 41 taxonomic families. Concerning NPSF in natural plant communities, we found evidence of this phenomenon for a total of 411 vascular plants belonging to 72 plant families. NPSF occur in most of the terrestrial ecosystems, including tropical and temperate forests, coastal sand dunes, old fields and grassland, deserts, as well as heathland and tundra. Three main hypotheses have been proposed to explain SS: (i) soil nutrient depletion or imbalance; (ii) build-up of soilborne pathogen and parasite populations, coupled with a shift in soil microbial community composition; (iii) release of phytotoxic and autotoxic compounds during decomposition of crop residues. Evidences from both agro-ecosystems and natural plant communities undoubtedly ruled-out the nutrient deficiency as a primary causal factor. Moreover, the massive use of mineral fertilizers, especially under intensive cultivation systems, appears an incorrect strategy that only exacerbates the decline of soil quality by inducing acidification and salinization. Soilborne pathogens are often isolated from symptomatic plants and many autotoxic compounds have been identified and quantified from sick soil. However, both the pathogenic and autotoxicity hypotheses are still unable to fully explain the species-specificity, as well as the long durability of SS observed in field conditions. The recent discovery that extracellular DNA (exDNA) has self-inhibitory effects, support the autotoxicity hypothesis, nevertheless this is a totally new topic, and more solid and systematic field investigations are needed. A better understanding of the causes of SS is a necessary step to develop eco-friendly solutions to overcome this problem.

The impact of fire on sand dune stability: Surface coverage and biomass recovery after fires on Western Australian coastal dune systems from 1988 to 2016

This study aims to determine the common response of coastal sand dunes in Western Australia (WA) to fire on decadal time-scales, in terms of ecological-geomorphic-climatic interactions to test the hypothesis that fire plays a role in coastal dune destabilisation. Fires are commonly suggested to have contributed to widespread dune reactivation in Australia and globally, a hypothesis that is relatively untested. We used data from the Landsat Thematic Mapper, Enhanced Thematic Mapper Plus, and Operational Land Imager missions to monitor changes in surface coverage on coastal sand dunes in south-west WA after fires. We analysed 31 fire scars from 1988 to 2016 in two Landsat scenes on the west and south coast of WA. Recovery ratios derived from the Normalised Difference Vegetation Index (NDVI) were used to monitor patterns in post-fire biomass and surface cover. Recovery ratios are correlated with indices of burn severity, and meteorological data to investigate relationships. We also used Maximum Likelihood Classification to monitor changes in bare sand area. Results suggest that recovery followed a strongly consistent pattern, and is characterised by rapid vegetation cover re-establishment within six to twelve months. Prior to this, some aeolian activity may have occurred but without substantial surface changes. Initial germination and/or resprouting were followed by steady growth up to seven years, where NDVI typically neared pre-fire values. Some variation in early recovery occurred between the west and south coast, possibly owing to relative proportions of reseeding and resprouting plants. A log regression explained 75% of the recovery pattern (79% on the south coast). Precipitation had some ability to explain recovery up to nine months post-fire (r2=0.29 to 0.54). No relationships were observed between estimates of burn severity and recovery. After nine months, the biggest cause of spatial variation in recovery was the pre-fire community composition and related seedbank or resprouting density. Image classification did not identify any new blowout features except where fires were not the primary cause. Results suggest that fires are not presently contributing to the destabilisation of coastal dunes in south-west WA.

Flora en playas y dunas costeras de México

Antecedentes y Objetivos: Se presenta el primer listado florístico de las playas y dunas costeras de México, actualizado y respaldado por ejemplares de herbario.Métodos: Se revisaron 14 herbarios nacionales y extranjeros. Se sobrepuso una retícula de 2 × 2 km al mapa de la costa y de las dunas costeras de México para referir todos los registros que corresponden a 2180 sitios con 12,419 ejemplares de plantas. Se calcularon índices de diversidad, similitud, diversidad taxonómica y redundancia.Resultados clave: La flora registrada consta de 153 familias, 897 géneros y 2075 especies de plantas vasculares, las cuales representan 9.5% de la flora vascular de México. Las cinco colecciones con índices de redundancia altos IR≥0.7 son los herbarios de la Universidad Nacional Autónoma de México (MEXU, IR=0.9), del Centro de Investigación Científicas de Yucatán (CICY, IR=0.8), y los del Centro de Investigaciones Biológicas del Noroeste (HCIB), el Instituto de Ecología, A.C. (XAL) y el del Museo de Historia Natural de San Diego (SD), cada uno con un IR de 0.7. Se reconocen cinco regiones florísticas que corresponden a los mares de México. El Pacífico Norte tiene mayor diversidad taxonómica y el Pacífico Sur menor diversidad taxonómica. El Golfo de California, Golfo de México y Mar Caribe tienen diversidades taxonómicas similares. Las especies con más registros son Trianthema portulacastrum (165), Croton punctatus (107), Echites umbelllatus (106) e Ipomoea pes-caprae (90). Por el carácter de ecotono de las dunas costeras, la mayoría de las especies se comparten con los tipos de vegetación vecinos (selvas, matorrales, y humedales como las marismas y manglares).Conclusiones: Esta primera lista de la flora en playas y dunas de México es la base para múltiples estudios florísticos regionales y locales, biogeográficos, y ecológicos; además, que será importante para su uso en temas de impacto ambiental y manejo costero.

Spatial Distribution of Halophytes in the Goraebul Coastal Sand Dune, Korea

Spatial Distribution of Halophytes in the Goraebul Coastal Sand Dune, Korea

우리나라 해안사구의 현황과 사회·경제적 특성 고찰

우리나라 해안사구의 현황과 사회·경제적 특성 고찰

On the taxonomy of the Italian endemic Hoplia dubia (Rossi, 1792), with the description of two new species (Coleoptera: Scarabaeidae: Melolonthinae)

Hoplia (Hoplia) dubia (Rossi, 1792) (Coleoptera: Scarabaeidae: Melolonthinae: Hopliini) is a species that is endemic of Italy, recorded for scattered localities along the coasts of the peninsula and of Sicily. Following the study of a rather large amount of specimens from the entire known range, Hoplia dubia is herein split into three allopatric species. The true Hoplia dubia is redescribed and a neotype is designated. Two new species, Hoplia (Hoplia) meridiana and Hoplia (Hoplia) messapia, are described and the Hoplia dubia species group is defined. For each species, a full description is given and diagnostic characters are summarized and compared in a table. The three species belonging to the group may be recognized mainly by morphological and chromatic differences in scales, scales density, and by setal pattern, which are all illustrated. Remarks on ecology, ethology, and phenology of adults of the species are also reported. All three species treated in this paper are restricted to coastal sand dunes. The significant loss of this habitat due to anthropogenic pressure raises concern about the conservation status of these species.

O-26 越後平野の砂丘列を形成する2つの堆積システム(3.沖積層研究の新展開,口頭およびポスター発表,一般講演)

O-26 越後平野の砂丘列を形成する2つの堆積システム(3.沖積層研究の新展開,口頭およびポスター発表,一般講演)

Geomorphological analysis and classification of foredune ridges based on Terrestrial Laser Scanning (TLS) technology

Along the North Adriatic Sea coast (Italy), vulnerability to climate change is further aggravated by anthropogenic influences, such as strong subsidence rate due to deep groundwater and gas abstraction, tourism and industry impacts. In this context, conservation and restoration of coastal sand dunes become extremely important especially because of their importance in terms of ‘natural’ coastal defense. This paper proposes an innovative geomorphological approach based on Terrestrial Laser Scanning - TLS, which allows us to measure and monitor morphometric dune evolution with high precision and details. Several TLS surveys were performed along the Ravenna coast (Adriatic Sea, Italy) and the resulting Digital Elevation Models (DEMs) were analyzed in order to classify the foredune ridges in three geomorphological sub-zones. The topographic, areal and volumetric variations over time of geomorphological units were calculated by GIS tools in order to identify seasonal trends or particular pattern. Meteo-marine climate conditions were also analyzed and Principal Component Analysis (PCA) was performed to correlate changes in morphology with meteo-marine forcing factors, highlighting the ones that most influence dune evolution and dynamics.