Coastal Sand Dunes Research Articles

Disentangling native and alien plant diversity in coastal sand dune ecosystems worldwide

AbstractAims(a) To disentangle the global patterns of native and alien plant diversity on coastal sand dune ecosystems across habitats and floristic kingdoms; (b) to determine the main drivers of variation in species richness in native and alien species in these endangered ecosystems; and (c) to test for an interaction between spatial scale and native–alien richness patterns, as predicted by the invasion paradox.LocationGlobal.MethodsWe collated a dataset of 14,841 vegetation plots in coastal sand dune ecosystems from around the world. Generalized Linear Models (GLMs) and Generalized Linear Mixed Models (GLMMs) were used to assess the patterns and main ecological determinants underlying native and alien species richness. Variation partitioning revealed the relative importance of environmental and anthropogenic variables.ResultsGLMs revealed strong differences among both habitats and floristic kingdoms in the number of native and alien species. Specifically, native species richness increased along the sea–inland gradient and was higher in the Cape and Paleotropical kingdoms. In contrast, alien species richness was relatively similar across habitats and kingdoms, though some differences were detected. There were strong differences between the drivers of native and alien richness; anthropogenic factors such as gross domestic product were positively associated with alien richness whereas native richness was more strongly related to environmental factors. Furthermore, we found a weak support for an invasion paradox effect.ConclusionsOur results revealed the complexity of causal processes underpinning coastal sand dune plant biodiversity and highlight the importance of considering native and alien species separately. Recognizing these differences while researching variation in biodiversity patterns and processes at multiple spatial scales will lead to a better mechanistic understanding of the causes of invasion worldwide, and in coastal ecosystems in particular, allowing the development of more focused control and management measures.

Geological evidence of high-energy marine flooding events on the Tangier coastal plain, Morocco

The coastal sedimentary record is currently being studied to investigate evidence of past extreme coastal flooding events. Extreme marine inundations along Morocco's coasts are described in historical documents. In this work, evidence of high-energy marine flooding events on the Tangier coastal plain (the Ain Guemout area) was obtained by studying the size and mineralogy of quartz grains, performing exoscopy of the grains, and reconstructing their possible source sediments. In Ain Guemout, the inundation had run-up heights of more than 10 m and deposited distinct metric boulders, broken shells, sand, and lithic clasts 1 km inland. These unusual deposits typically underwent abrupt basal contact with a paleosoil. The deposits were found to thin and fine landward and present major structural and significant lateral variation. Textural analysis showed that clay and coarse sand are the most abundant grain populations in the sediments. The sand fraction is moderately or poorly sorted with a few well-sorted sandy deposits. In contrast to possible source sediments (coastal dune and beach sand), microtextural analysis indicated the recurrent presence of fresh surfaces and percussion marks. The deposits showed similarities to beach and coastal dune materials in their assemblages of heavy minerals, and presented a decreasing trend in such assemblages up-unit. The altitude reached by the sand layers, the increased boulder size inland, and the abundance of rip-up clasts in the sediments demonstrate the tsunamigenic origin of the Ain Guemout deposits. These results improve our understanding of marine floods, and should aid the development of strategies to protect coastal environments.

Arenibacterium halophilum gen. nov., sp. nov., a halotolerant bacterium in the family Rhodobacteraceae isolated from a coastal sand dune.

A Gram-stain-negative, non-pigmented, non-spore-forming, motile, strictly aerobic bacterial strain, designated CAU 1492T, was isolated from a coastal sand dune and its taxonomic position was examined using a polyphasic approach. Cells of strain CAU 1492T grew optimally at 30 °C, pH 7.0 and in 3 % (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence of CAU 1492T showed that it formed a distinct lineage within the family Rhodobacteraceae as a separate deep branch, with 96.8 % or lower sequence similarity values to representatives of the genera Marivita, Donghicola, Sulfitobacter, Marinovum, Phaeobacter, Primorskyibacter, Roseovarius and Aestuariihabitans. Strain CAU 1492T was closely related to Marivita geojedonensis DPG-138T (96.8 %), Donghicola eburneus SW-277T (96.7 %), Sulfitobacter porphyrae SCM-1T (96.7 %), Marinovum algicola FF3T (96.6 %) and Aestuariihabitans beolgyonensis BB-MW15T (96.4 %) based on 16S rRNA gene sequences. The major cellular fatty acids of strain CAU 1492T were cyclo-C19 : 0 ω8c and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c). The polar lipid pattern was composed of phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid and an unidentified aminolipid. The strain contained Q-10 as the sole respiratory quinone. The draft genome of strain CAU 1492T was 4.63 Mb with a DNA G+C content of 63.1 mol%. The genome includes 4292 protein-coding genes and a five rRNA operons. On the basis of the phenotypic, chemotaxonomic and genomic data, strain CAU 1492T represents a novel genus in the family Rhodobacteraceae for which the name Arenibacterium halophilum gen. nov., sp. nov. is proposed. The type strain of Arenibacterium halophilum is CAU 1492T (=KCTC 62998T=NBRC 113696T).

Geomorphological and ecological change in a coastal foreland dune system, Sandscale haws, Cumbria, UK: the management challenges posed by climate change

Many coastal sand dune systems in the UK and other parts of the world have experienced a decline in bare sand extent and dune mobility over the past 70 years, accompanied by increased coverage of coarse grass, scrub and woodland vegetation. This has raised concerns amongst nature conservationists about the survival of dune specialist species. Opinions are divided, however, regarding what management interventions should be made to counteract these trends. This paper reviews the factors which have contributed to progressive dune system stabilization at Sandscale Haws, located on the Irish Sea coast in Northwest England, considers the implications for the site of UKCP18 future climate change projections, and discusses the options and plans for future adaptive management. Analaysis of aerial photographs indicated a large reduction in bare sand area between 1946 and 1988 (from >34% to 9% of the dune system), since when there has been a further decline to 1.7%. Consideration of the evidence suggests that a trend towards a warmer, slightly wetter and less windy climate has been the main driver of stabilization, although atmospheric nitrogen deposition, increasing atmospheric CO2 concentrations, reduced grazing intensity, reduced human disturbance from the mid-1980s onwards and a tendency for shoreline progradation on the west-facing coast have played contributing roles. Some species characteristic of open habitats can still be found in good numbers in parts of the dune system, but without increased management it is likely they will decline further and some may become locally extinct. Since the site is of national and international importance for a number of nationally scarce plant and animal species it is considered that there is both a legal and an ethical duty to attempt to maintain suitable habitat for their survival. As a National Nature Reserve Sandscale Haws provides a suitable ‘natural laboratory’ within which to research the effectiveness of different intervention methods. A number of small-scale dune rejuvenation methods have been trialled since 2015, and options for larger scale interventions, including turf stripping and possible dune notching, are currently being evaluated as part of the nation-wide Dynamic Dunescapes project.

Coastal habitats across sea-to-inland gradient sustain endangered coastal plants and Hymenoptera in coastal dune ecosystems of Japan

Coastal sand dune ecosystems have been lost and increasingly fragmented due to human use and disaster prevention over the past few decades. Generally, habitat fragmentation and connectivity loss have led to the decline of species biodiversity. In coastal dune ecosystems, habitat loss across the coastal gradient may be a major driver of the decline in coastal species diversity and ecosystem functions. In this study, we assessed the species richness of coastal plants and hymenopteran insects in fragmented coastal dunes of Japan using six sites with and without back-dune habitats. We recorded plant species and their flowering status monthly from April to September 2018 and examined the effects of landscape factors on plant species richness. We also assessed the species richness of hymenopteran bees and wasps and compared their determinants with those of plants. In total, we identified 109 plant species, including 33 native coastal plants (10 of which are endangered) and 40 exotic plants. The number of native plant species was positively affected by the presence of back-dune habitat and sand dune size, while that of native coastal plant species was positively affected only by the presence of back-dune habitat. In contrast, the number of exotic plant species was dependent only on sand dune size. We recorded 58 hymenopteran species including 28 bee pollinators and 30 predatory wasp species. The number of hymenopteran species was positively related to the number of native plant species for both bees and wasps. In conclusion, habitat loss across the coastal gradients led to decreased species richness of native coastal plant species, resulting in reduced species richness of pollinator and predatory insect communities. Most of the coastal areas across sea-to-inland gradients have been lost due to recent disaster prevention activities. Our results highlight the urgent need for biodiversity conservation of endangered species in remnant coastal dune ecosystems.

Microbial communities of polyhydroxyalkanoate (PHA)-based biodegradable composites plastisphere and of surrounding environmental matrix: a comparison between marine (seabed) and coastal sediments (dune sand) over a long-time scale

Most researches on the plastisphere in coastal environments deal with plastics floating in seawater. Comparatively smaller attention has been devoted to the plastisphere of plastics buried in marine sediments, and very little is known on that of plastics on coastal sand dunes. Yet, limited information is available on the impact of plastics, especially biodegradable plastics, on microbial organisms in their surroundings. Nevertheless, a large amount of plastics sink on the seabed or is deposited on beach-dune systems.We investigated the succession of plastisphere microbial community on two biodegradable composites based on poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and seagrass fibres (PHBV/PO), buried in seabed and dune sediments over a 27 months period in mesocosm. PHBV is regarded as a valuable alternative to conventional plastics and PHBV/PO has recently been designed for applications in coastal habitat restoration. We also examined the degradation rate and impact of these plastics on the microbial communities of surrounding sediments.Microbial communities of the surface of PHBV and PHBV/PO in seabed and dune sand differ from those of surrounding sediments, displaying a lower richness. Plastics colonization occurs largely from bacteria present in surrounding sediments, although the contribution from the water column bacterial pool could be not negligible for plastics in the seabed. No significant differences were detected between the communities of the two plastics and no significant impact of plastics on microbial community of the surrounding sediments was detected. The exceptional long duration of this study allowed to gain information on the succession of a plastisphere community over a previously unexplored time scale. Succession appears highly dynamic in dune sand even after two years, while the community structure in seabed seems to reach stability after one year. These findings highlight the importance of performing long-term studies when trying to characterize composition and dynamics of plastisphere bacterial communities.

Coastal sand dune restoration with an eco-friendly technique

Dune restoration projects that integrate vegetation efforts with natural, sustainable, and soft solutions have become increasingly popular in coastal communities. Eco-restored dunes have high aesthetic value and are likely to be more resilient to near-surface wind effects and/or minor storms events. However, environmental-friendly restoration strategies still lack scientific insight from systematic research and the role of eco-restoration in dune erosion resistance and resilience has not yet been rigorously investigated. The question is: how can we optimize eco-friendly solutions in dune ecosystem restoration to maximize the resistance and resilience of coastal dunes against erosion from wind, wave, and storm surge attack? The present paper proposes an innovative colloidal silica-based consolidation technique for coastal sand dunes. A special focus is placed on the description of the experience gained from two pilot field studies started in Salento coastal area, in the south of Italy. The preliminary observations clearly show that mineral colloidal silica increases the mechanical strength of non-cohesive sediments allowing the adopted solution to reduce the volume of dune erosion and the dune scarp retreat rate, thus improving the resistance and resilience of the dune system. Besides furthering our knowledge of coastal erosion, the results of these and future studies will be of value to coastal managers and policy makers responsible for dune restoration projects.

Higher Winter-Spring Temperature and Winter-Spring/Summer Moisture Availability Increase Scots Pine Growth on Coastal Dune Microsites Around the South Baltic Sea

Coastal sand dunes near the Baltic Sea are a dynamic environment marking the boundary between land and sea and oftentimes covered by Scots pine (Pinus sylvestris L.) forests. Complex climate-environmental interactions characterize these ecosystems and largely determine the productivity and state of these coastal forests. In the face of future climate change, understanding interactions between coastal tree growth and climate variability is important to promote sustainable coastal forests. In this study, we assessed the effect of microsite conditions on tree growth and the temporal and spatial variability of the relationship between climate and Scots pine growth at nine coastal sand dune sites located around the south Baltic Sea. At each site, we studied the growth of Scots pine growing at microsites located at the ridge and bottom of a dune and built a network of 18 ring width and 18 latewood blue intensity tree-ring chronologies. Across this network, we found that microsite has a minor influence on ring width variability, basal area increment, latewood blue intensity, and climate sensitivity. However, at the local scale, microsite effects turned out to be important for growth and climate sensitivity in some sites. Correlation analysis indicated that. the strength and direction of climate-growth responses for the ring width and blue intensity chronologies were similar for climate variables over the 1903-2016 period. A strong and positive relationship between ring width and latewood blue intensity chronologies with winter-spring temperature was detected at local and regional scales. We identified a relatively strong, positive influence of winter-spring/summer moisture availability on both tree-ring proxies. When climate-growth responses between two intervals (1903-1959, 1960-2016) were compared, the strength of growth responses to temperature and moisture availability for both proxies varied. More specifically for the ring-width network, we identified decreasing temperature-growth responses, which is in contrast to the latewood blue intensity network, where we documented decreasing and increasing temperature-growth relationships in the north and south respectively. We conclude coastal Scots pine forests are primarily limited by winter or winter-spring temperatures and drought despite differing microsite conditions. We detected some spatial and temporal variability in climate-growth relationships that warrant further investigation.

Effects of Forest Types and Environmental Factors on Soil Microbial Biomass in a Coastal Sand Dune of Subtropical China

Coastal sand dune ecosystems generally have infertile soil with low water-holding capacity and high salinity. However, many plant species have adapted to the harsh sand environment along the southeastern coast of China. Studying the microbial biomass in such an ecosystem can improve our understanding of the roles that microbes play in soil fertility and nutrient cycling. We investigated the differences in soil microbial biomass carbon (MBC) and nitrogen (MBN) contents and their seasonal dynamics in five forest types (a secondary forest and plantations of Casuarinas, Pine, Acacia, and Eucalyptus). The results indicated that the seasonal variations of soil MBC and MBN contents in all five forest stands were higher in spring and winter, but lower in summer and autumn. The MBC content was lower in the Casuarinas plantation than in the other plantations in the same soil layer. However, no significant differences were observed in MBN contents among the different forest types. The MBC and MBN concentrations were positively correlated with soil moisture, but negatively correlated with soil temperature. The MBC and MBN contents also decreased with increasing soil depth. Across all soil layers, secondary forest had the highest MBC and MBN concentrations. Our study also showed that the MBC and MBN contents were positively affected by total soil carbon (TC), pH, and litter N content, but were negatively impacted by soil bulk density and litter C content. Moreover, the MBN content was positively correlated with root N content. In summary, environmental factors and the differences in litter and fine roots, soil nutrient contents, as well as the soil physical and chemical properties caused by different tree species collectively affected the concentrations of the soil MBC and MBN.

Genetic Structure of Invasive Baby's Breath (Gypsophila paniculata L.) Populations in a Michigan Dune System.

Coastal sand dunes are dynamic ecosystems with elevated levels of disturbance and are highly susceptible to plant invasions. One invasive plant that is of concern to the Great Lakes system is Gypsophila paniculata L. (perennial baby’s breath). The presence of G. paniculata negatively impacts native species and has the potential to alter ecosystem dynamics. Our research goals were to (1) estimate the genetic structure of invasive G. paniculata along the Michigan dune system and (2) identify landscape features that influence gene flow in this area. We analyzed 12 populations at 14 nuclear and two chloroplast microsatellite loci. We found strong genetic structure among populations (global FST = 0.228), and pairwise comparisons among all populations yielded significant FST values. Results from clustering analysis via STRUCTURE and discriminant analysis of principal components (DAPC) suggest two main genetic clusters that are separated by the Leelanau Peninsula, and this is supported by the distribution of chloroplast haplotypes. Land cover and topography better explained pairwise genetic distances than geographic distance alone, suggesting that these factors influence the genetic distribution of populations within the dunes system. Together, these data aid in our understanding of how invasive populations move through the dune landscape, providing valuable information for managing the spread of this species.

Impact of invasive alien plants on native plant communities and Natura 2000 habitats: State of the art, gap analysis and perspectives in Italy

Invasive alien plants are a major threat to biodiversity and they contribute to the unfavourable conservation status of habitats of interest to the European Community. In order to favour implementation of European Union Regulation no. 1143/2014 on invasive alien species, the Italian Society of Vegetation Science carried out a large survey led by a task force of 49 contributors with expertise in vegetation across all the Italian administrative regions. The survey summed up the knowledge on impact mechanisms of invasive alien plants in Italy and their outcomes on plant communities and the EU habitats of Community Interest, in accordance with Directive no. 92/43/EEC. The survey covered 241 alien plant species reported as having deleterious ecological impacts. The data collected illustrate the current state of the art, highlight the main gaps in knowledge, and suggest topics to be further investigated. In particular, the survey underlined competition as being the main mechanism of ecological impact on plant communities and Natura 2000 habitats. Of the 241 species, only Ailanthus altissima was found to exert an ecological impact on plant communities and Natura 2000 habitats in all Italian regions; while a further 20 species impact up to ten out of the 20 Italian administrative regions. Our data indicate that 84 out of 132 Natura 2000 Habitats (64%) are subjected to some degree of impact by invasive alien plants. Freshwater habitats and natural and semi-natural grassland formations were impacted by the highest number of alien species, followed by coastal sand dunes and inland dunes, and forests. Although not exhaustive, this research is the first example of nationwide evaluation of the ecological impacts of invasive alien plants on plant communities and Natura 2000 Habitats.

Dune migration and volume change from airborne LiDAR, terrestrial LiDAR and Structure from Motion-Multi View Stereo

Sand dunes are commonly regarded as a challenge to traditional photogrammetry due their homogeneous texture and spectral response. In this work we present an evaluation of Structure from Motion-Multi View Stereo (SfM-MVS) to obtain high-resolution elevation data of coastal sand dunes based on images acquired by Remotely Piloted Aircraft (RPA). A Digital Elevation Model (DEM) of a dunefield in Southern Brazil was generated from 810 photos captured by an RPA at 100 m above the takeoff point in February 2019. Image matching was successful in all areas of the survey due the presence of superficial features (footprints and sandboard tracks) and visibility of the sedimentary stratification, highlighted by heavy minerals. Altimetric accuracy of the SfM-MVS DEM was validated by comparison with Terrestrial LiDAR (TLS) data collected during the same fieldwork campaign of the RPA flights. The SfM-MVS DEM was then compared to an Airborne LiDAR (ALS) DEM from October 2010. While the SfM-MVS and TLS DEMs are very similar, without any major difference in elevation or in the reconstruction of topographic features, the SfM-MVS DEM presents a small scale surface roughness not visible in the TLS DEM. The Feature Preserving DEM Smoothing (FPD) algorithm was applied to the SfM-MVS DEM with good results in terms of surface smoothing, but without any significant changes in descriptive statistics and error metrics, with an RMSE of 0.08 m and MAE of 0.06 m for both the original and the FPD-filtered DEM. Displacement of dune crest lines from the ALS and SfM-MVS DEMs resulted in a migration rate of ≈5 m/year between 2010 and 2019, in good agreement with rates derived from satellite images and historical aerial photographs of the same area. Sand volume change in the same period showed a decrease of only 0.2%, which can be related to the installation of sand fences to promote dune stabilization and sand removal from the front of the dune field to keep a road open to vehicles. ALS can cover large areas in little time but its high cost still remains a barrier to wider usage, especially by researchers in developing countries. TLS has an intermediate cost but demands more fieldwork and more processing time. In our case we needed three days for the TLS survey and around three weeks to produce a DEM of ≈80 400m2. On the other hand, we were able to cover ≈740 900m2 with six flight missions in under three hours, with ≈13 h processing time in a medium-range workstation. This makes SfM-MVS a low-cost solution with fast and reliable results for 3D modelling and continuous monitoring of coastal dunes.

First report of lesion nematode on new host, Deverra tortuosa, in Mersa Matruh coast, Egypt

Nematological survey was carried out in 2019 on wild plants viz., Aeluropus lagopoides, Ammophila arenaria, Cakile maritime, Deverra tortuosa, Euphorbia paralias, Inula crithmeides, Lotus polyphyllos, Ononis vaginalis, Pancrtium maritimum, Polygonum equisetiforme, Thymelaea hirsuta and Zygophyllum album, colonized the coastal sand dunes habitat of Mersa Matruh, Egypt. Specimens of lesion nematode (Pratylenchus spp.) were collected from rhizosphere soil of Deverra tortuosa Synonym: Pituranthos tortuosus (Desf.) Asch. and Schweinf herb (family: Apiaceae, old Umbelliferae). Lesion nematode was identified based on morphology of females. According to available literature, this is the first report of Pratylenchus on wild plant (Deverra tortuosa) colonized Egypt. More surveys are needed to identify other genera or species of phytonematodes that might occur in Egypt, including weeds, grasses and wild plants in desert areas, also the dissemination of lesion nematode must be explored as well as other plant-feeding nematodes and it is advisable to investigate the nearby cultivated plants.

Sedimentological, mineralogical and geochemical investigation of Essaouira’s coastal dune system: potential origin and provenance

Quaternary coastal sand dunes occur frequently along the Atlantic coast of Morocco and result from the combined effect of river discharge, littoral drift, winds, vegetation, and other meteorological conditions. In this paper, we investigate the textural and compositional parameters of the coastal dune sands of Essaouira across the Ksob riversides, as well as their provenance. Morphologically, they occur as present-day active dunes, Holocene fossil dunes and Pleistocene aeolianite deposits. To investigate the grain provenance, we have opted for laboratory analyses including grain size, mineralogy, microtextures, and micromorphology of quartz grains. Sands from Holocene fossil and active dunes revealed very fine to medium mean grain size and a moderate sorting, while those of the Pleistocene aeolianites showed fine to very fine mean grain size and very poor sorting. Studied dunes showed the dominance of grain shapes varying from sub-rounded to fresh angular. Regarding mineralogy, calcite bioclasts are prevalent in sands of the right bank of the river, while quartz is more abundant in dunes located at the left bank. In the active dunes of the left bank, other carbonates were also detected in bioclasts such as aragonite, dolomite, and magnesian calcite, suggesting a marine provenance. The siliciclastic grains of the studied generations of aeolian dunes are likely originating from Triassic, Jurassic, and Quaternary units crossed by the Ksob River. In fact, the results revealed the presence of minerals such as albite, plagioclase, microcline, and orthoclase which could have been sourced from Triassic basalts and gypsum which is often associated to Jurassic evaporitic rocks. This study allowed to suggest the probable origin of the sands that form these dunes based on the detailed study of their grains, which has not been studied on previous research works of the area. In addition, this research is of particular relevance as it fits into the current research trend related to understanding the evolution of Plio-Quaternary coastal dune systems in the world and could be applicable to other dune systems of the Atlantic coast of Morocco in the future.

An experimental study of mitigating coastal sand dune erosion by microbial- and enzymatic-induced carbonate precipitation

Due to more extreme weather events and accelerating sea-level rise, coastal sand dunes are subjected to more frequent storm wave inundation and surge impacts, which contribute to widespread coastal erosion problems. In this study, two novel bio-mediated methods, microbial-induced carbonate precipitation (MICP) and enzymatic-induced carbonate precipitation (EICP), were investigated and compared for their effectiveness in mitigating sand dune erosion under wave attack. Small-scale laboratory model tests were performed on MICP-treated, EICP-treated, and untreated sand dunes at dune slope angles and two wave intensities for up to 2 h. The cross-shore profile was captured continuously during the course of the erosion test. The erosion volume above the still water level (SWL) and landward retreat distance at the SWL were calculated based on the captured bed profiles. The results show that both EICP and MICP could substantially reduce sand dune erosion at mild-to-moderate wave and dune slope conditions. However, the effectiveness of MICP treatment deteriorated at steeper dune slopes with longer period of wave attack. Under the most adverse condition (i.e., steepest dune slope, biggest wave, and longest period of wave attack), neither EICP nor MICP could effectively mitigate erosion. Fundamentally, the variable effectiveness of MICP and EICP treatment for sand dune erosion control was attributed to the spatial distribution pattern of formed calcite precipitation, which was determined by the way how EICP and MICP were applied. The calcite precipitation was relatively uniform in EICP-treated sand dunes. In MICP-treated ones, however, substantial calcite precipitation concentrated in the shallow surface layer as confirmed by the surface penetration test and SEM observation.

Landscape Change and Associated Increase in Habitat Fragmentation During the Last 30 Years in Coastal Sand Dunes of Buenos Aires Province, Argentina

The Eastern Barrier of Dunes (EBD) and Southern Barrier of Dunes (SBD) extend along the coast of Buenos Aires province, Argentina. These regions have been severely altered by anthropic activities for years, mainly through the development of cities and afforestation with exotic species. We quantified the effect of anthropic activities on the landscape of coastal dunes, evaluating its temporal evolution during the last 30 years. Using Landsat satellite images from 1985, 1996, 2005, and 2015, we performed supervised classifications and obtained thematic maps for coastal dune barriers. Over these maps, we quantified the main classes of natural habitats and anthropic environments and analyzed changes in their extent and arrangement over time. Temporal analyses showed a gradual replacement of anthropic environments over natural habitats. During the last 30 years, the area impacted by anthropic activities went from 13 to 31.7% on the EBD and from 3.6 to 5.9% on the SBD. In the SBD, fragmentation along the main natural habitats increased over the years, whereas fragmentation along the EBD, although higher than that in SBD, remained constant through time. Drastic reductions of the extent of natural habitats were recorded at or near areas where anthropic environments developed. Both coastal dune barriers showed a clear advance of anthropic fragmentation over coastal dune habitats, with EBD being the most impacted by human activities.

First Report of Root-lesion Nematode, Pratylenchus on New Host, Deverra tortuosa, in Mersa Matruh Coast, Egypt- A Pilot Study

Nematode survey was carried out in 2019 on wild plants viz., Aeluropus lagopoides (Molleih), Ammophila arenaria (Gazzoof), Cakile maritime (Figl el-gamal), Deverra tortuosa (guezah), Euphorbia paralias (Sakrran), Inula crithmeides (Golden samphire), Lotus polyphyllus (Qam el- gamal or Qrana), Ononis vaginalis (Hotaiba), Pancratium maritimum (Bosseil), Polygonum equisetiforme (Horsetail knotweed), Thymelaea hirsute (Mithnaan), and Zygophyllum album (Ratrayt), colonized the coastal sand dunes habitat of mersa matruh, Egypt. specimens of root-lesion nematodes (Pratylenchus spp.) were collected from rhizosphere soil of D. tortuosa Synonym: Pituranthos tortuosus (Desf.) Benth. & Hook f. Asch. & Schweinf herb (family: Apiaceae, old family: Umbelliferae). Root-lesion nematode was identified based on morphological characteristics of females. According to available literature, this is the first report of Pratylenchus on wild plant (D. tortuosa) growing in Egypt. More surveys are needed to identify other genera or species of phytonematodes that might occur in Egypt, including weeds, grasses and wild plants in desert areas, also the dissemination of lesion nematode must be explored as well as other plant-parasitic nematodes and it is advisable to investigate the nearby cultivated plants.

백령도 가을리에 분포하는 고(古)해안사구층의 특성과 형성 시기

The Baengnyeongdo-island, located at the northernmost point of the west coast, has developed several coastal landforms. Although the coastal landforms of Baengnyeongdo-island are widely used as a tourism resource, a lot of academic research has not been conducted. In this study, particle size analysis, XRF, and OSL age dating were performed on the BR sandy deposits to find out the formation of coastal sand dunes on Baengnyeongdo-island. Based on the physicochemical properties, the BR section was divided into three parts; BR-A, BR-B and BR-C. First, about 56ka, which corresponds to the MIS 3, fine sand was deposited and forms the BR-C section. Second, the BR-B which located middle part of BR section, showed reversed age stratigraphy. The BR-B was interpreted as reworked sediments based on sedimentary facies and chemical weathering intensity. And, the BR-A composed of fine and medium sands was formed in middle Holocene. This research has significance in that it finds out the paleo sand dunes formed in Pleistocene. This study can contribute to understanding coastal sand dune development on the west coast.

Woody plant community and distribution in a tropical coastal sand dune in southern Thailand

In this study, we aimed to clarify the forest structure and species composition of a coastal sand dune and the relationship between topographical factors and woody plant distribution at the Bang Boet coastal sand dune, Southern Thailand. Three permanent transect plots (10 × 100 m) covering both windward and leeward aspects were established 300 m apart. In subplots (10 × 10 m) of each transect, all woody plants with a diameter at breast height larger than 1 cm were tagged, measured, and identified. The topographic factors were recorded for each subplot. Non-multidimensional scaling was employed to analyse the woody plant distribution, which was tested for statistical significance. We identified 36 species from 32 genera and 23 families. Species diversity was moderate based on the Shannon–Wiener index (2.81). The density and basal area of all woody plants was 3110 ± 361 stem·ha−1 and 7.34 ± 0.87 m2·ha−1, respectively. The dominant trees species based on the importance value index were Pandanus odorifer, Syzygium antisepticum and Syzygium grande. The forest structure could be classified into two canopy layers, with an open and closed crown canopy on the windward and leeward aspects, respectively. Overall, the distribution of woody plants was significantly correlated with aspect. Species diversity, tree abundance, and basal area differed significantly between the windward and leeward aspects and quantitative values were low on the windward aspect. Due to strong winds and salt spray on the windward side, the woody plant community and distribution favoured the leeward side.

Conservation status of Italian coastal dune habitats in the light of the 4th Monitoring Report (92/43/EEC Habitats Directive)

Coastal dunes are among habitats with the worst conservation status on a global, European and national scale. Monitoring and reporting are of strategic importance to determine the effectiveness of the implementation of Habitats Directive and to preserve the unique biodiversity heritage of the Italian dunes. In this study we show main results of the 4th National Report with specific reference to the macro-habitat “Coastal Sand Dunes and Inland Dunes”, highlighting its updated current conservation status at the national and Biogeographical level. A comprehensive Working Group of territorial experts collected, updated, validated and integrated the data available for 11 Annex I Habitats, distributed in the Alpine, Continental and Mediterranean Biogeographical Regions. The conservation status was evaluated through the following criteria: geographic range, surface area, structure, functions, pressures, threats, conservation measures and prospects. Results highlighted the dramatically bad conservation status of Italian dune Habitats: the overall assessment reported 88% of habitats in bad conservation status and the remaining 12% is in inadequate conditions. Results showed a generalised threat and a worrying conservation status both on herbaceous and wooded communities, in particular in some relevant habitats, such as the shifting dunes. Main pressures and threats were linked to residential, commercial and industrial activities, as well as alien species. Although some of the changes in distribution and trends are probably deriving from more accurate and updated data, the alarming conservation status of Italian sand dunes requires a better knowledge of pressures and threats for further management actions and monitoring plans, inside and outside protected areas.