Grey Dunes Research Articles

Cladonia homosekikaica Nuno new to Sweden – a cup lichen found in the grey dunes of Gotland

Cladonia homosekikaica Nuno new to Sweden – a cup lichen found in the grey dunes of Gotland

The spider fauna of Danish coastal dune habitats revisited after 25 years: evidence of faunistic impoverishment

Arthropod faunas have become impoverished in recent years in abundance as well as in diversity, but so far little evidence exists concerning spiders. In 2022, we repeated pitfall trap collections of spider assemblages completed 25 years previously in coastal dune habitats of the Hanstholm Reserve of National Park Thy, Denmark. Traps were placed approximately at the same spots, i.e. the habitats (white dune, grey dune, dry dune heathland, wet dune heathland, low pine plantation) were represented approximately as before. Contrary to most previous reports of insect decline, we found only weak evidence of reduction in abundance, but strong indications of reductions in faunistic value based on changes in ecological traits. Within the same period of spring and with the same number of traps, we collected 12% fewer spider individuals and 13% fewer species; rarefaction indicated that the lowered species richness was real. Species diversity had decreased and dominance increased. Changes in indices of ecological traits showed that the fauna had changed into decreased contribution of habitat specialists and species of restricted Danish distribution; the proportion of aeronauts had increased; the average body size had decreased. Indices of assemblage microclimatic niche positions and niche widths showed increased representation of shade and humidity loving species. Most of these changes were repeated in each of the habitats. Finally, we found evidence of a phenological shift towards activity earlier in spring in some species.Implications for insect conservationWe discuss possible management measures to counteract the observed trend towards reduced faunistic value.

Coastal foredune enlargement – a sign of sea-level change? An example from the Kavatsite beach-dune system

Sea level rise is one of the effects of climate change and the Black Sea is affected, regardless its isolated position from the World Ocean. As a consequent, in various locations worldwide is reported shifting of foredune ridges towards inland and overlapping of newly formed ridges over older secondary features, as parabolic dunes, dune fields, etc. During the field study in 2023, in the Kavatsite foredune ridge was observed such migration of newly formed accumulations on older grey dunes. Comparative analysis of UAV-based photogrammetry and generated orthophoto mosaic overlaid to archive aerial images from the early 20th century showed over 20 m migration of the primary dune ridge inland and also increased beach erosion. Regarding the accelerating sea rise tendency, special attention should be taken to the anthropogenic activities in the coastal zone, including the beach-dune systems – the first natural barrier to the wave action on coasts.

The Impact of Breeding Yellow-Legged Gulls on Vegetation Cover and Plant Composition of Grey Dune Habitats

The establishment of large populations of yellow-legged gull Larus michahellis in coastal and urban areas can lead to strong changes in vegetation cover and composition through creating physical disturbance in the vegetation and impacting the soil quality through defecation. In this study, we evaluated the effects of breeding yellow-legged gull populations on tall and short vegetation cover and plant species composition in old (occupied for 13 years) and new (occupied for 3 years) colony sites in grey dunes of the Algarve, southern Portugal. In each site, sampling plots were used to measure the percentage of vegetation cover in areas with and without breeding gulls. In the old colony site, the cover by tall vegetation was substantially reduced and the cover by short vegetation substantially increased in the areas where gulls are breeding in comparison with the adjacent areas. In the new colony sites, there were only minor differences. The increase in cover of short vegetation in the breeding area of the old colony site was mostly by nitrophilous species (Paronychia argentea and Malcolmia littorea) and should be explained by the decrease in vegetation cover of tall plant species and by feces deposition. Tall and slow-growing species Suaeda maritima and Helichrysum italicum covers were negatively affected. Our results showed that yellow-legged gulls affected vegetation cover and composition of grey dunes after 3 years of consecutive breeding, and this should be considered in the management of these habitats where breeding yellow-legged gulls are increasing.

Effects of invasive Rosa rugosa on Baltic coastal dune communities depend on dune age

Rosa rugosa Thunb. (Japanese Rose) is one of the most invasive species in Europe. It spreads spontaneously in coastal areas of western, central and northern Europe, posing a threat to dune habitats, including those indicated in the EU Habitats Directive as particularly valuable. R. rugosa has already been reported to displace native plants and alter soil properties. However, little is known about how these effects are mediated by the habitat context or the invader condition (health, ontogenetic stage). This study addressed that gap by examining vegetation and soil in 22 R. rugosa-invaded sites, half of which were in yellow dunes and the other half in grey dunes, i.e. two habitats representing the earlier and later stages of dune succession. The study was conducted on the Hel Peninsula (Poland’s Baltic coast). R. rugosa had a significant impact on dune vegetation, but the impact was strongly dependent on the habitat type. In the yellow dune sites, R. rugosa outcompeted most resident plant species, which translated into a strong decline in their total cover and richness. The invasion was almost not accompanied by changes in soil properties, suggesting that it affected the resident vegetation directly (through space takeover and shading). In the grey dunes, R. rugosa caused a shift in species composition, from that characteristic of open communities to that typical of forests. In this habitat, a significant increase in the soil organic layer thickness under R. rugosa was also observed, which means that both direct and indirect effects of the invasion on the vegetation should be assumed. Finally, a negative relationship was found between the total chlorophyll content in R. rugosa leaves and the parameters of resident plant communities, showing that the invasion effects can vary not only across habitats, but also with the condition of the invader. The results may have practical implications for managing R. rugosa invasions in coastal sand dune systems. Since R. rugosa accelerates grey dune succession, protecting this habitat may be more urgent and, at the same time, more complicated than protecting dunes at the earlier stages of development.

Distribution and Ecology of Neophyte Lactuca Tatarica Population on the East Baltic Sea Coast in Latvia

Abstract There is an increasing need for species occurrence data at a regional level for the global assessment of invasiveness of neophytes. Therefore, the distribution and habitats of Lactuca tatarica (L.) C.A. Mey. in Latvia (Baltic Sea region) was studied. L. tatarica was observed for the first time in Latvia in 1920. During the next 60 years, it was mainly found in synanthropic habitats. Since the 1980s, the species has spread along the Gulf of Riga (the Baltic Sea) coast. In 2019, recent data on the distribution of L. tatarica were obtained in a large-scale habitat mapping project. Lactuca tatarica was observed in 147 polygons (total area of 230 ha) representing nine habitat types of EU importance. The largest proportion of L. tatarica localities was recorded in beach habitats, and the highest abundance and total area in white and grey dunes. Lactuca tatarica was observed in the following associations: Cakiletum maritimae, Honckenyetum peploidis, Elymo-Ammophiletum arenariae, and Festucetum polesicae. In most localities, L. tatarica genets are scattered or in small groups covering small areas. In some coastal sections (southern part of the Gulf), L. tatarica forms dense stands that tend to spread. Lactuca tatarica in Latvia is considered as a neophyte successfully naturalised mainly in coastal dune habitats, and in some locations it corresponds to the criteria of invasive species with a high risk to endanger natural habitats.

A new index to assess the state of dune vegetation derived from true colour images

Vegetation on coastal dunes is a key element, as it promotes the growth and stabilization of these landforms while contributing significantly to biodiversity. Physical (e.g. impact of storms), ecological (e.g. animal grazing) and human-related (e.g. farming and recreation) factors may disturb coastal dune vegetation, changing dune dynamics and eventually inducing ecogeomorphic state shifts. Therefore, understanding vegetation dynamics and state turns crucial to predict dune evolution paths. The latter must be supported by observations combined with the development of tools (e.g. indexes) able to detect eventual changes and to automatically categorize the state of the vegetation. Here, a multi-step index to characterise the dune vegetation state (DUVES) was developed and tested in Barreta Island (South Portugal), where grey dune vegetation has declined in recent years. The index was computed using classified true colour orthophotos and orthomosaics derived from UAS (Unmanned Aerial Systems) surveys. Google Earth images were used as complementary data to analyse the evolution trends. The possible sources of disturbance (i.e. human-related activities and gull occupation) were also investigated by comparing their distribution with the vegetation changes. DUVES successfully identified different states of vegetation cover that expressed its stability, perturbation or growth based on temporal changes and allowed the analysis of their evolutionary trends. The distribution of perturbation was mostly associated with gull nesting areas, increasing over time, and to a less extent to human-related activities. The observed grey dune habitat loss was due to replacement of plants typical from this habitat by ruderal species promoted by the positive feedback established between gulls and vegetation. The developed index proved to be of great utility to define dune habitat evolution and understand the associated drivers, being a tool with a wide range of applications, namely for improving future coastal management actions aimed at conserving dune habitats. Moreover, DUVES is potentially transferable due to its easy adaptability depending on the particularities of each study site or goal.

The Rapid Effects of Yellow-Legged Gull (Larus michahellis) Colony on Dune Habitats and Plant Landscape in the Atlantic Islands National Park (NW Spain)

The Atlantic Islands of Galicia Maritime/Terrestrial National Park hosts one of the largest breeding colonies of yellow-legged gull (Larus michahellis) in the world. In 2002, a new yellow-legged gull breeding colony was established on the Punta Muxieiro dune complex, which also harbors rare and threatened plant species and habitat types of community interest according to Directive 92/43/EEC. This study assesses the effect of this colony on two habitats of community interest: white dunes and grey dunes. For this purpose, plant cover and soil properties, composition, and nutrient content were monitored in plots with different gull densities. Moreover, historic aerial images were compiled to observe changes in the plant landscape of the dune system. The results showed that, despite the recentness of the occupation of the dune system by yellow-legged gull species, significant changes in acidic–alkaline processes and nutrient availability were already observed in soils. Soils in plots with higher gull density showed more acidic pH values and a higher content of the most labile N and P fractions. Moreover, a decrease in plant cover and number of species was also demonstrated in plots with higher gull densities. Finally, the presence of ruderal and alien species such as Urtica membranacea and Parietaria judaica was also observed.

Vegetation Characteristics and Recent Successional Trends of Sand Dune Habitats at the Bulgarian Black Sea Coast

Coastal dunes are valuable and vulnerable habitats that require scientific exploration and understanding of their natural processes; therefore, the aims of this study were to determine the current vegetation characteristics of dune habitats along the Bulgarian Coast in terms of species richness and cover of typical psammophytes and different non-psammophytic plant groups, and to analyze how they respond to certain environmental drivers. Data were collected from 12 dune systems. The research was focused on embryonic, white and grey dunes. The field work was conducted throughout July and August 2017. The vegetation was sampled at 154 phytosociological plots (5 m × 5 m). To understand how the vegetation responds to different drivers, we tested the correlation of defined species group richness and cover in relation to (1) the soil pH and EC values, (2) the distance from inland to the sea and (3) the range of different categories of land cover in the surrounding area. In order to track temporal vegetation changes, we compared the cover of defined species groups between 2003 and 2017. We registered a total number of 269 vascular plants, 12 bryophytes and 5 lichens. The strongest presence in all dune types, both in species richness and cover, was the group of grass- and shrubland plants. Weeds and ruderal plants had significant coverage in grey dunes, while the richness and cover of forest and alien plants were negligible among the studied dune habitats. The comparison of data between 2003 and 2017 revealed a substantial decline in the cover of psammophytes. We observed a clear pattern regarding the share of species richness of psammophytes and non-psammophytes among different locations. We detected that grey dunes were the most affected by the penetration of non-psammophytes.

Using fine-scale field data modelling for planning the management of invasions of Oenothera stucchii in coastal dune systems

Invasive alien species risk assessment and adaptive management are often hindered by a lack of information for most species. This work aims at predicting the probability of successful establishment and invasion of Oenothera stucchii Soldano, a neophyte invasive species belonging to the sect. Oenothera subsect. Oenothera, in xerophilous grasslands of grey dunes. Based on fine-scale field data, we modelled O. stucchii presence/absence and abundance as a function of environmental factors, human disturbance, and attributes of the recipient community through a zero-inflated Poisson model. The invasion success of O. stucchii depended on a combination of factors which differed when considering either the patterns of occurrence (species presence/absence) or those of species abundance. While human-driven disturbance strongly influenced the probability of presence/absence of O. stucchii, patterns of abundance were mostly driven by a combination of environmental and biotic features. Attributes of the recipient community remarkably influenced both O. stucchii presence and abundance. Based on fine-scale field data, we determined the mechanisms which drive the spatial patterns of presence and abundance of O. stucchii in xerophilous grasslands and provided quantitative thresholds to identify the most susceptible areas of grey dune habitats prone to invasion, which combine human disturbance (distance from the nearest beach access), attributes of the resident community (resident vegetation cover and structure), and environmental disturbance (foredune ridge height). These results provide useful insights to be used to plan cost-effective measures to prevent O. stucchii establishment and spread in sandy coastal systems. Our model may also be applied to closely related congener species included in the subsect. Oenothera, sharing similar biological and ecological traits.

Resilience in coastal dune grasslands: pH and soil organic matter effects on P nutrition, plant strategies, and soil communities

AbstractSoil organic matter (SOM) and pH are key ecosystem drivers, influencing resilience to environmental change. We tested the separate effects of pH and SOM on nutrient availability, plant strategies, and soil community composition in calcareous and acidic Grey dunes (H2130) with low, intermediate, and/or high SOM, which differ in sensitivity to high atmospheric N deposition. Soil organic matter was mainly important for biomass parameters of plants, microbes, and soil animals, and for microarthropod diversity and network complexity. However, differences in pH led to fundamental differences in P availability and plant strategies, which overruled the normal soil community patterns, and influenced resilience to N deposition. In calcareous dunes with low grass‐encroachment, P availability was low despite high amounts of inorganic P, due to low solubility of calcium phosphates and strong P sorption to Fe oxides at high pH. Calcareous dunes were dominated by low‐competitive arbuscular mycorrhizal (AM) plants, which profit from mycorrhiza especially at low P. In acidic dunes with high grass‐encroachment, P availability increased as calcium phosphates dissolved and P sorption weakened with the shift from Fe oxides to Fe‐OM complexes. Weakly sorbed and colloidal P increased, and at least part of the sorbed P was organic. Acidic dunes were dominated by nonmycorrhizal (NM) plants, which increase P uptake through exudation of carboxylates and phosphatase enzymes, which release weakly sorbed P, and disintegrate labile organic P. The shifts in P availability and plant strategies also changed the soil community. Contrary to expectations, the bacterial pathway was more important in acidic than in calcareous dunes, possibly due to exudation of carboxylates and phosphatases by NM plants, which serve as bacterial food resource. Also, the fungal AM pathway was enhanced in calcareous dunes, and fungal feeders more abundant, due to the presence of AM fungi. The changes in soil communities in turn reduced expected differences in N cycling between calcareous and acidic dunes. Our results show that SOM and pH are important, but separate ecosystem drivers in Grey dunes. Differences in resilience to N deposition are mainly due to pH effects on P availability and plant strategies, which in turn overruled soil community patterns.

Key Aesthetic Appeal Concepts of Coastal Dunes and Forests on the Example of the Curonian Spit (Lithuania)

The main objective of the study was to elicit key concepts determining the aesthetic appeal of coastal dunes and forests using the example of the Curonian Spit (Lithuania). The mixed approach included three methods: (1) paired comparison survey of 45 coastal landscapes, (2) semi-structured interviews with local inhabitants, and (3) eliciting the key aesthetic appeal concepts by a panel of experts using the Delphi technique. The results of the paired comparison survey show that the most aesthetically appealing landscapes of the Curonian Spit are: (1) white mobile dunes, (2) white dunes with grey (grassland) dunes in the background, and (3) grey dunes with white dunes in the background. The local inhabitants considered the concept of visual coherence as the best, explaining the aesthetic appeal of the dune and the forest landscapes on the spit. The experts of the Delphi survey considered that the concepts of stewardship, naturalness, imageability, and visual scale best define the scenic appeal. The appeal of the least attractive landscapes, in their opinion, was shaped by the concepts of naturalness, disturbance, and complexity. We conclude that the notions of visitors, local inhabitants and experts differ on the aesthetic appeal concepts of coastal dunes and forests, suggesting potential management conflicts.

Valuation of aesthetic ecosystem services of protected coastal dunes and forests

This study was implemented in the context of the emerging concept of aesthetic ecosystem services (AES) of coastal protected dunes and forests. The main problem addressed was that many coastal management research case studies focusing on AES still rely on the objectivist paradigm, eliciting aesthetic values based on objective sets of criteria independent from human perception ‘here and now’. This doesn't use the knowledge accrued from several decades of psychophysical studies in landscape aesthetics using photographs as visual stimuli, due to the complexity of the psychophysical approach. The study bridges this major research gap by eliciting the preferences for and the attractiveness of coastal landscapes that are founded in the landscape's physical attributes. An innovative ‘quali-quantitative’ methodology was applied, combining both quantitative (paired comparison survey) and qualitative (semi-structured in-depth interviews) methods for valuation and interpretation of coastal AES. The main aim of the study was to test a ‘quali-quantitative’ methodology for the valuation of AES of protected coastal dunes and forests, using the Curonian Spit (Lithuania) as a case study. The key finding of the quantitative survey was that domestic summer visitors found the open landscapes of the Curonian Spit most attractive, especially 1) White mobile dunes; 2) White dunes with grey dunes in the background; 3) Grey dunes with white dunes in the background. The main result of the qualitative survey was that local stakeholders living on the Curonian Spit consider the concept of visual coherence as best explaining the aesthetic appeal of the dune and forest landscapes on the spit. The main associated policy recommendation to coastal management policymakers on the Curonian Spit, and in other protected coastal dune areas, is to pay more attention to AES along with the care for biodiversity conservation and for other tangible dune ecosystem services.

Low-Cost UAV for High-Resolution and Large-Scale Coastal Dune Change Monitoring Using Photogrammetry

In this paper, coastal dune data are collected at Truc Vert, SW France, using photogrammetry via Unmanned Aerial Vehicles (UAVs). A low-cost GoPro-equipped DJI Phantom 2 quadcopter and a 20 MPix camera-equipped DJI Phantom 4 Pro quadcopter UAVs were used to remotely sense the coastal dune morphology over large spatial scales (4 km alongshore, i.e., approximately 1 km2 of beach-dune system), within a short time (less than 2 h of flight). The primary objective of this paper is to propose a low-cost and replicable approach which, combined with simple and efficient permanent Ground Control Point (GCP) set-up, can be applied to routinely survey upper beach and coastal dune morphological changes at high frequency (after each storm) and high resolution (0.1 m). Results show that a high-resolution and accurate Digital Surface Model (DSM) can be inferred with both UAVs if enough permanent GCPs are implemented. The more recent DJI Phantom 4 gives substantially more accurate DSM with a root-mean-square vertical error and bias of 0.05 m and −0.03 m, respectively, while the DSM inferred from the DJI Phantom 2 still largely meets the standard for coastal monitoring. The automatic flight plan procedure allows replicable surveys to address large-scale morphological evolution at high temporal resolution (e.g., weeks, months), providing unprecedented insight into the coastal dune evolution driven by marine and aeolian processes. The detailed morphological evolution of a 4-km section of beach-dune system is analyzed over a 6-month winter period, showing highly alongshore variable beach and incipient foredune wave-driven erosion, together with wind-driven inland migration of the established foredune by a few meters, and alongshore-variable sand deposition on the grey dune. In a context of widespread erosion, this photogrammetry approach via low-cost flexible and lightweight UAVs is well adapted for coastal research groups and coastal dune management stakeholders, including in developing countries where data are lacking.

Is penetration of non-psammophytes an underestimated threat to sand dunes? - a case study from western Pontic coast

The aim of this study was to identify how far the different dune types from one of the largest dune complexes at the Bulgarian Black Sea Coast are affected by the penetration of non-psammophytes and if there is an upward trend in their number. We studied the Kamchia dune system during 2013–2015. Vegetation was sampled at 162 plots along 12 transects systematically situated to cover three different habitats: embryonic, white and grey dunes. All vascular plants as well as cover percentage of each species and total vegetation cover were registered within each plot. The overall species list of the different dune types was additionally completed for the whole study area. A total 207 plant species were registered. They were classified into five groups as follows: psammophytes – 38, weeds and ruderals – 36, plants typical of grasslands and shrublands – 95, plants typical of forests – 18 and alien (including invasive) species – 20. Number and cover of defined groups were calculated in respect to their distribution in different dune habitats. Results show that grey dunes contain the highest percentage of non-psammophytic plants, which decrease towards white and embryonic dunes. The studied coastal area is still less influenced by non-psammophytes. It represents an example of a Bulgarian Black Sea coastal dune complex that is relatively unaffected by urbanization. The high floristic and habitat diversity deserve further effective protection.

Natural risks and vulnerabilities of dynamic coastal dune landscapes

Set in the Habitats Directive as priority habitat, fixed dunes with herbaceous vegetation (grey dunes) occur around the coasts of Europe. As a part of many coastal dune systems these habitats are especially complex and low resilience and need special attention from the conservation and management perspectives. Nearly a decade we have studied representative examples of fixed dunes in Estonia. Due to growing anthropogenic pressure and ongoing global changes it is vital to distinguish the changes and analyse general trends of development of grey dunes. The selected sites Keibu (located on the NW coast of mainland Estonia) and Ruhnu (located on the eastern coast of Ruhnu Island) are representative examples in Estonia, with a coverage of a geographical range and ecological variation. Both sites are part of conservation and monitoring areas. In each site, we have compiled a landscape profile to visualize the topography, vegetation and soils. he study was carried out on perpendicular to shoreline landscape profiles in order to express the full spectrum of coastal dune plant communities and surface deposits from shores towards inland. Both, natural and human impacts have been considered in the assessment of changes in the structure and functioning of the grey dunes in Estonia. The results show that changes in dune landscapes can be rapid, especially on sandy beaches due to stronger storm surges in recent decades. The inland areas are more affected by human activity and the changes there are well reflected. The gradual loss of open sandy habitats on the sites is evident during the last 100 years and show the overall development trends of dynamic coastal dune landscapes. This study has proven that these areas need permanent observation to assess the level of changes. It is vital to contribute to the decision making processes concerning their optimal use and conservation needs to maintain their resilience.

Edge contrast does not modulate edge effect on plants and pollinators

Edge contrast, is one of the main determinants of edge effects. This study examines the response of plant and pollinator diversity (bees and butterflies) to forest edge contrast, i.e. the difference between forests and adjacent open habitats with different disturbance regimes. We also investigated a potential cascading effect from plants to pollinators and whether edge structure and landscape composition mediate the relationship between edge contrast and beta diversity of pollinators. We sampled 51 low-contrast edges where forests were adjacent to habitats showing low levels of disturbance (i.e. grey dunes, mowed fire-breaks, orchards, grasslands) and 29 high-contrast edges where forests were adjacent to more intensively disturbed habitats (i.e. tilled firebreaks, oilseed rape) in three regions of France. We showed that plant diversities were higher in edges than in adjacent open habitat, whatever the edge contrast. However, plant beta diversity did not differ significantly between low and high-contrast edges. While we observed higher pollinator diversities in adjacent habitats than in low-contrast edges, there were no significant differences in pollinator beta diversity depending on edge contrast. We did not observe a cascading effect from plants to pollinators. Plant and bee beta diversities were mainly explained by local factors (edge structure and flower cover) while butterfly beta diversity was explained by surrounding landscape characteristics (proportion of land cover in grassland).

Invasive plants induce the taxonomic and functional replacement of dune spiders

Understanding the impacts caused by invasive plants on higher trophic levels is fundamental to predict future changes to native communities. Invasive plants like Acacia longifolia can change habitat structure and thereby alter the taxonomic and functional diversity and composition of predator communities. This work aims to evaluate the effect of this invasive plant species on spider assemblages, at both taxonomic and functional levels, in grey dunes. Spiders were sampled in six native and six invaded sites, in northwestern Portugal. Individuals were identified to species level and their functional features were quantified. Generalized Linear Models (GLM) were used to compare differences of species richness, abundance, functional diversity (FDQ) and trait proportions between native and invaded dunes. We also assessed the relative contribution of replacement and richness differences to overall taxonomic and functional dissimilarity between native and invaded dunes. GLMs showed that there was no change in species richness between dune types, but there was a significant increase in FDQ in invaded dunes. Significant shifts in the proportion of trait categories were observed. Native dunes favoured ambush hunters and myrmecophagous species. On the contrary, invaded dunes favoured species that inhabit leaf litter, web builders and crustaceophagous species. The proportion of diurnal species was higher in native dunes, contrary to invaded dunes, where both diurnal and nocturnal species dominated. Taxonomic and functional dissimilarity was mainly determined by the replacement, not the net loss, of species and traits. These results showed that functionally different spider species were favoured by the invasion of Acacia longifolia. The invasion of Acacia longifolia certainly attenuated the extreme habitat conditions normally found in grey dunes, allowing the immigration of more generalist species from neighbouring habitat types into invaded dunes. Thus, it can be concluded that there was no homogenization, taxonomic or functional, but changes in the composition of spider assemblages and the replacement of functions after dune invasion.

Synecology of Cutandia maritima (L.) Barbey, a rare psammophytic species along the Montenegrin Coast (East Adriatic Coast)

Abstract Cutandia maritima is a circum-Mediterranean species that inhabits sandy dunes along the coast line. It is fairly frequent on the western Adriatic coast but fairly rare and possibly even non-native in the east. In Croatia, it was discovered in 1990 in Crnika Bay on the island of Rab, which was considered until 2005 to be the only site on the eastern Adriatic coast from the Gulf of Trieste in the north to Corfu in the south. In 2009, the species was briefly reported for Velika plaža (Long Beach) in Ulcinj (Montenegro) but without details about the habitat type and synecology. The aim of this paper is thus to provide a deeper insight into the ecology and synecology of C. maritima in the eastern Adriatic part of the distribution area. On Velika plaža in Ulcinj, the species was found along the whole sea-inland gradient of sand dunes, in various types of vegetation: [1210] - annual vegetation of drift lines, [2110] - embryonic shifting dunes, [2120] - shifting dunes with Ammophila arenaria (white dunes), [2220] - dunes with Euphorbia terracina, [2130*] - fixed coastal dunes with herbaceous vegetation (grey dunes), and also [2190] - humid dune slacks.

Larval habitat preferences of a threatened butterfly species in heavy-metal grasslands

Understanding the factors that determine habitat quality is of vital importance in ensuring appropriate habitat management. Here we used the Niobe fritillary (Argynnis niobe) as a study system to analyse the larval habitat preferences in a small network of heavy-metal grasslands in western Germany. The data were compared with the results of a previous study in coastal dune grasslands of the German North Sea. Based on this knowledge, we give management recommendations for the conservation of this threatened species. The key factors for the survival of A. niobe in heavy-metal grasslands were (i) open vegetation with a warm microclimate and (ii) sufficient host plants for the larvae. This reflects similar results from the previous study in coastal grey dune grasslands. However, in the heavy-metal grasslands, physiological stress generally slows down succession and favours the fritillary’s host plant, the metallophyte Viola calaminaria. As a result, the cover of the host plant was nearly twice as high in heavy-metal grasslands compared to the dune grasslands. Heavy-metal grasslands are of great significance for the conservation of A. niobe and overall butterfly diversity. Usually, the speed of succession in heavy-metal grasslands is slow and, hence, sites with high heavy-metal concentrations are characterised by relatively stable plant composition and vegetation structure. However, on soils with low heavy-metal content a loss of habitats of A. niobe and associated species of conservation concern may occur without management. On those sites sheep grazing seems to be an appropriate way to keep the habitats open and rich in violets.