The final floristic total of 661 vascular plant taxa in the project dataset confirms the DDBR coastal area's botanical importance. This richness spans several ecological groups: psammophilous plants of open sand, halophytes of salt-affected soils, hygrophilous species of wet depressions, grassland and shrub species, and ruderal elements that occur locally under human influence. The broader significance of this floristic diversity is supported by published syntheses of the Danube Delta flora (Ciocârlan 2011).

Poaceae was the richest family in the coastal inventory, with 101 taxa (15.3% of the total flora), followed by Asteraceae with 86 taxa (13.0%) and Chenopodiaceae with 53 taxa (8.0%). Together, these three families accounted for 240 taxa, representing 36.3% of the recorded vascular flora. Other well-represented families included Brassicaceae (35 taxa), Caryophyllaceae (33), Fabaceae and Cyperaceae (32 each), and Lamiaceae (24). The prominence of Poaceae, Chenopodiaceae, Cyperaceae, Brassicaceae, and Caryophyllaceae is consistent with the extensive representation of grasslands, dunes, saline surfaces, wet depressions, and pioneer habitats within the DDBR coastal mosaic.

The supporting dataset includes the vascular-plant checklist, the list of 47 vegetation associations, conservation categories and sources, sector/habitat assignments, observation provenance, and generalised coordinates for sensitive taxa. Sector-level richness is not compared statistically because survey effort was heterogeneous; the figures are therefore treated as descriptive summaries of the assembled coastal inventory.

The 47 plant associations recorded in the project dataset indicate that coastal vegetation is not a simple linear sequence from the sea to inland areas. Instead, it forms a discontinuous mosaic. Annual pioneer communities develop on open beaches and freshly disturbed sand; dune-building communities occur where sand begins to accumulate; perennial dune grasslands occupy more stable sites; saline depressions support halophilous assemblages; and locally developed shrubs mark sectors with greater substrate stability or lagoonal influence. Popescu and Sanda (1976), Sârbu et al. (1995, 2000), Popescu et al. (1997), Sanda and Arcuș (1999), and Făgăraș (2016) have documented similar phytosociological diversity in deltaic and coastal sectors.

The conservation importance of a coastal site depends not only on its size, but also on the variety and condition of the habitats it contains. Maintaining this mixture of habitats is important for conserving the coastal flora. Rarity, ecological function, microhabitat diversity, and vulnerability must also be considered.

The most valuable sectors are those where natural beach dynamics, dune development, and saline or wet depressions coexist. In such places, several vegetation types can occur side by side, creating conditions for many specialised species. Conversely, sectors subject to repeated mechanical disturbance, trampling, or overgrazing tend to lose this fine-scale structure and become floristically simplified.

Beach and strandline vegetation form the first living cover above the active shore. These communities are often sparse and seasonal, yet ecologically important, as they initiate colonisation of open sand and may trap organic material and sediment. They are also among the most vulnerable to mechanical beach cleaning and intensive recreational use. Fig. 2 shows the most frequent geoelements in the dataset.

Their interpretation as conservation-relevant coastal habitats aligns with the European and Romanian Natura 2000 habitat frameworks (Gafta and Mountford 2008; European Commission 2013).

Embryonic dunes and mobile dune communities form where sand accumulation stabilizes. Their plant species tolerate shifting sand, wind exposure, and low nutrient availability. By capturing sand and reducing substrate mobility, they create conditions for later stages of vegetation. Damage to these communities can disrupt dune formation and increase the shoreline’s vulnerability. Published studies of beach-dune systems on the Danube Delta coast underscore the importance of such functional zones for the persistence of rare psammophilous species (Strat 2016).

Semi-fixed and fixed dune vegetation supports a richer flora, including many perennial psammophytes and species of high conservation value. These habitats may appear modest, but they are important reservoirs of coastal biodiversity. Their stability depends on the balance between natural disturbance and the absence of excessive human pressure.

Wet interdune depressions and saline flats add ecological complexity to the area. Temporary flooding, groundwater mineralisation, evaporation, and microrelief shape them. These sites can support halophytes, hygrophilous species, and mixed communities that differ markedly from the adjacent dry dunes. Coastal shrubs and Tamarix-related vegetation further enhance habitat structure in protected sectors or lagoon-facing positions. The ecological importance of salt-affected coastal surfaces in the Danube Delta region is also evidenced by studies of Juncus maritimus vegetation and other halophytic systems (Ciocârlan et al. 2013; Făgăraș 2016). Table 2 summarises the ecological roles and corresponding management implications of these vegetation groups.

The dataset identified 58 taxa with Romanian Red List status and 42 priority taxa as particularly important to the phytodiversity of the DDBR coastal area. These include species with restricted distributions, taxa listed in red lists, plants characteristic of natural beaches and dunes, halophytes of maritime depressions, and species with small or vulnerable local populations. These species add to the ecological distinctiveness of the coastal area and make it particularly valuable for botanical research. The interpretation of their conservation relevance was cross-checked against Romanian Red List sources and regional conservation literature (Oltean et al. 1994; Petrescu 2007, 2015; Dihoru and Negrean 2009; Făgăraș et al. 2010). Ecological specialization and flagship value are treated as management attributes rather than threat categories. Fig. 3 shows their family-level distribution, while Table 3 summarises representative taxa, ecological settings, conservation significance, and main sensitivities.

Of the 661 vascular plant taxa recorded in the coastal inventory, 603 (91.2%) were not assigned a conservation category in the Romanian Red List and Red Book sources used in this study. The remaining 58 taxa (8.8%) included 43 taxa classified as rare (R), nine as vulnerable/rare (V/R), three as endangered/rare (E/R), two as endangered (E), and one as vulnerable (V). These categories reflect the historical national conservation sources consulted and should not be interpreted as a new assessment under the current IUCN criteria. Nevertheless, they identify a substantial group of conservation-relevant taxa requiring periodic field verification and population monitoring.

Alyssum borzaeanum, Crambe maritima, Argusia sibirica, Centaurea pontica, Asparagus brachyphyllus, Convolvulus persicus, Dianthus bessarabicus, Eryngium maritimum, Stachys maritima, and Limonium bellidifolium span a range of conservation statuses. Some are psammophytes of open maritime sands; others are halophytes of salt-affected depressions or taxa with Pontic, Ponto-Caspian, Atlantic-Mediterranean, or regional endemic affinities. The findings indicate that species of conservation interest occur across a wide range of ecological settings. Management should therefore consider the connections among species and habitats across the coastal landscape instead of focusing only on isolated rare-plant locations (Petrescu 2007; Ciocârlan 2011).

The database contained 1,243 occurrence records representing 111 species profiles across 134 source grid squares. Of these records, 841 (67.7%) intersected at least one mapped Natura 2000 habitat at the grid-square level. Species richness by habitat was highest for habitat 1410 (96 profiles; 86.5% of all profiles) and habitat 1310 (90; 81.1%), followed by 2110 (71; 64.0%), 2160 (69; 62.2%), 1210 (65; 58.6%), and 2130* (59; 53.2%). The strongest compositional overlap occurred between habitats 1310 and 1410 (83 shared profiles; Jaccard = 0.806; Sørensen = 0.892), followed by 2110 and 2160 (60 shared profiles; Jaccard = 0.750; Sørensen = 0.857) (Fig. 4).

Qualitative population dynamics were reported as stable for 52 profiles (46.8%), decreasing for 50 (45.0%), increasing for six (5.4%), and unclear for three (2.7%). Keyword screening identified grazing or overgrazing in 98 species profiles (88.3%), tourism or development in 50 (45.0%), beach cleaning or mechanical disturbance in 46 (41.4%), restricted or reduced habitat area in 44 (39.6%), and low reproductive or dispersal capacity in 36 (32.4%) (Fig. 5). These pressure frequencies are non-exclusive summaries of the species accounts, not estimates derived from a controlled impact-sampling design.

The analysis points to three conservation patterns. Habitats 1310 and 1410 support particularly high species richness, underlining the contribution of both annual and perennial saline vegetation to the coastal flora. The frequent overlap between habitats 2110 and 2160 also suggests a close spatial relationship between young dunes and more established dune-shrub vegetation. At the same time, the similar proportions of stable and declining populations show that high regional richness does not necessarily mean that local populations are secure. Although these observations are based on habitat assignments made at source-grid level, they can help guide future surveys and identify management priorities.

The eleven taxa discussed below illustrate the range of habitats and conservation challenges found along the DDBR coast. Each account summarizes distribution, habitat affinity, documented pressures, and management implications from the dataset and cited literature. The 11 detailed accounts were selected purposively from the 42 priority taxa to represent the main coastal habitat types, contrasting biogeographic affinities, high national conservation concern, restricted or small local populations, and direct exposure to the principal pressures recorded. Localities described as “confirmed” refer to observations from the 2009–2018 dataset; other named localities are explicitly identified as bibliographic or historical records.

Alyssum borzaeanum is a rare psammophilous, plant found mainly in open, dry, or partly stabilised sandy habitatsalong the Romanian Black Sea coast. In the DDBR, it occurs in young and semi-stabilised dunes, where vegetation remains sparse and the sand can still move naturally. Associated plants include Convolvulus persicus, Centaurea arenaria subsp. borysthenica, Euphorbia seguieriana, Secale sylvestre, and Silene conica. Because the species is rare and closely tied to open-sand microhabitats, its populations are vulnerable to even relatively small changes in dune conditions. Trampling, vehicle traffic, mechanical beach cleaning, dune levelling, and the spread of ruderal vegetation are the main recorded pressures. Protecting the species will require retaining open sandy areas, avoiding unnecessary stabilisation, and regularly monitoring known populations (Oltean et al. 1994; Dihoru and Negrean 2009; Ciocârlan 2011; Strat 2016). Fig. 6 presents the plant’s habit, flower characteristics, and recorded distribution in the project dataset.

Crambe maritima grows on natural beaches, upper shores, and dune margins, and can serve as a recognisable flagship species for coastal conservation. Its presence in the DDBR indicates where strandline and pioneer vegetation can still develop under relatively natural beach conditions. Such sites retain drift material, varied substrates, and lower levels of mechanical disturbance. The species is often found near Eryngium maritimum, Stachys maritima, Polygonum maritimum, and Ammophila arenaria subsp. arundinacea. Picking, litter accumulation, intensive recreation, beach levelling, and mechanical cleaning can damage seedlings and remove the varied substrates required for establishment. In sensitive sectors, management should favour selective cleaning , restrict trampling and vehicle access, and guide visitors away from upper-beach vegetation (Petrescu 2007; Dihoru and Negrean 2009; Făgăraș et al. 2010; Strat 2016). Fig. 7 shows representative morphological features and the project localities.

Polygonum maritimum is a rare strandline and foredune species linked to natural upper beaches and maritime sands. It helps characterize the transition between open beach vegetation and embryonic dune communities, where small changes in disturbance, sand mobility, and drift-line material can strongly influence plant persistence. It occurs in the same broad ecological setting as Crambe maritima, Eryngium maritimum, Stachys maritima, and Asparagus brachyphyllus, and it contributes to the conservation value of relatively undisturbed beach-dune interfaces. The species is especially sensitive to mechanical beach cleaning, trampling, vehicle circulation, and removal of natural debris. The recommended measures are to avoid intensive cleaning in sectors with natural strandline vegetation, maintain undisturbed upper-beach strips, and include the species in rare-plant monitoring routes (Burduja 1954; Popescu and Sanda 1976; Dihoru and Negrean 2009; Strat 2016). The species and its distribution points in the project dataset are illustrated in Fig. 8.

Argusia sibirica (L.) Dandy is a characteristic maritime species of high conservation value, considered critically endangered in the Romanian Red Book and rare in older floristic sources. It was known from the Black Sea coast at Sulina, Sfântu Gheorghe, Ciotic, Portița, Sacalin Island, Letea, and Grindul Lupilor, and the project dataset confirmed it in all these areas, as well as on Musura Island and between Perișor and Periteașca. The species is linked to the Black Sea coast, central Russia, northern Anatolia, and a broader Eurasian range extending eastward to Japan (Panțu et al. 1936; Dihoru and Negrean 1976; Ciocârlan 2011). Ecologically, it behaves as a perennial heliophilous plant in moderately moist, neutral, nutrient-poor sandy soils. It has strong affinities for moist and slightly saline substrates, occurring in arenicolous communities with Bassia sedoides, Chenopodium glaucum, Eryngium maritimum, Lactuca tatarica, Salicornia europaea, Scolymus hispanicus, and Suaeda maritima, and locally in dune vegetation with Centaurea arenaria subsp. borysthenica, Euphorbia seguieriana, Gypsophila perfoliata, Leymus racemosus subsp. sabulosus, Secale sylvestre, and Silene conica. The data characterize it as perennial, amphimictic, barochorous, hydrochorous, and entomophilous (Dihoru and Negrean 2009), with flowers from May to August. The habitus, flower details, and project distribution points are shown in Fig. 9.

Its conservation value is related to sand fixation, fragrant flowers, melliferous potential, and its occurrence in ecologically sensitive coastal areas. Limiting factors include its position at the western edge of the range, mechanical beach cleaning, intense tourism, sand compaction, and trampling of juveniles. In situ conservation should focus on protecting and clearly marking the sites where the species occurs, especially near tourist facilities. For regional consistency, the name Argusia sibirica (L.) Dandy is retained following Euro+Med PlantBase (2026), which accepts this combination for the Euro-Mediterranean flora. The national conservation category used in the account follows Dihoru and Negrean (2009).

Centaurea pontica Prodan & Nyár. is one of the most important endemic elements of the Romanian coastal flora. It is listed as endangered or threatened in several red lists. Its distribution is limited to southeastern Romania, with records in the DDBR from Sulina and Ciotic, south of Sfântu Gheorghe. The field observations confirmed the presence of the species in the Sulina urban area, particularly near the basin and the belt-channel bridge. In contrast, the species was not recently found at Ciotic; renewed field verification is required. This taxon represents a Dobrogean coastal endemic and a component of Romania’s distinctive phytogenetic heritage (Prodan 1935; Dihoru and Pârvu 1987; Dihoru and Negrean 2009). It grows on maritime sands, often ruderalized and sometimes nearly bare, within the broader vegetation of the coastal belt, including Cakiletea maritimae and psammophilous communities such as Cynodontetum dactyli, Lactuco tataricae-Glaucietum flavae, and Argusio sibiricae-Petasitetum spuriae. In the dataset, it is described as a biennial species, amphimictic, entomophilous, and barochorous-anemochorous (Dihoru and Negrean 2009), flowering from July to November. Its conservation value is primarily scientific, owing to its rarity and endemic status. Main threats include urban expansion in Sulina, unmanaged tourism, a lack of local awareness, and a very small population. Reintroduction or introduction should not be recommended without feasibility assessment, genetic provenance, recipient-site suitability, permits, and post-release monitoring; habitat protection, seed banking, and research-led reinforcement should be preferred unless a formal recovery plan exists. The Sulina record and mapped project distribution are illustrated in Fig. 10.

Asparagus brachyphyllus Turcz. is a rare coastal plant associated with saline and moist maritime sands. It is treated as critically endangered in the Romanian Red Book and as rare in older floristic sources. Earlier records mention Istria and Grindul Chituc; however, the species was not detected during the project surveys at these historical sites. Instead, a few individuals were identified in the Periteașca–Perișor sector, making this one of the most important field confirmations in the dataset. Biogeographically, the species has a range from southeastern Romania toward Kazakhstan and may be interpreted as a Dobrogean-Pontic-Caspian coastal element (Ciocârlan 1994; Dihoru and Negrean 2009; Sârbu et al. 2013). The species is heliophilous and thermophilous, occurring on moderately moist, neutral, and nutrient-poor soils, especially on more or less saline maritime sands. It may occur with Euphorbia peplis, Lolium loliaceum, and Polygonum maritimum, and also in salt-affected vegetation with Aeluropus littoralis, Aster tripolium, Juncus gerardi, Juncus littoralis, Phragmites australis, Puccinellia gigantea, and Scirpus maritimus. The field data indicate low abundance and moderate cover, and the species is described as a perennial, amphimictic, entomophilous, and anemochorous plant (Dihoru and Negrean 2009), flowering from July to August. Its conservation value is mainly scientific, because of its rarity and restricted habitat. The principal limiting factors identified in this synthesis are the narrow habitat range, the small number of recorded individuals, and alteration of saline coastal habitats. The most viable conservation option is to combine strict protection of existing sites with seed collection, ex situ cultivation in botanical gardens, and carefully planned reintroduction into ecologically similar habitats. The Periteașca record and its mapped project locality are shown in Fig. 11.

Convolvulus persicus L. is a critically endangered Ponto-Caspian coastal plant and one of the most significant psammophilous species of the Romanian Black Sea coast. Historical and regional sources mention it from Sfântu Gheorghe, Mila 23, Sulina, C.A. Rosetti, Letea, Caraorman, Cardon, Sfiștofca, Perișor, and Portița. The project dataset confirmed it at Sfântu Gheorghe, Sulina, north of Sfântu Gheorghe, Perișor, and Sacalin Island. The notes indicate that one monitored site had already lost the species, that Perișor hosted only a few individuals, and that Sacalin supported numerous individuals on compact surfaces. This confirms the highly uneven and vulnerable distribution of the species along the DDBR coast (Prodan 1935; Panțu et al. 1936; Dihoru and Negrean 1976; Strat 2016). Ecologically, it is a psammophilous, xeromesophilous, thermophilous, and heliophilous species of dry, neutral, and nutrient-poor sands. It co-occurs with Alyssum borzaeanum, Bromus tectorum, Centaurea arenaria subsp. borysthenica, Euphorbia seguieriana, Medicago falcata, Secale sylvestre, and other dry-sand species and is connected with Convolvuletum persici and related dune communities. The field notes describe it as perennial, reproducing both sexually and vegetatively, and flowering from June to July. Its conservation value is high: it has ornamental value and helps stabilise sand. Threats include its position at the western limit of the range, ruderalization, and mechanical beach cleaning. Conservation should focus on maintaining all current sites, avoiding disturbance of foredunes, and reintroducing or reinforcing existing populations where local decline is evident, with actions undertaken only under an approved, evidence-based recovery protocol. Fig. 12 illustrates the species and distribution points documented in the project dataset.

Dianthus bessarabicus (Kleopow) Klokov is a rare and subendemic psammophilous species of the coastal sands. The project notes indicate records from Perișor, Sulina, Sfântu Gheorghe, Grindul Sărăturile, Grindul Lupilor, Cardon, Sfiștofca, C.A. Rosetti, Periprava, Letea, and Caraorman. Field confirmation was obtained in the Sfântu Gheorghe, Grindul Sărăturile, Perișor, Periteașca, and Sulina sectors. The taxon is interpreted as a Geto-Dobrogean element and is treated as threatened or rare in regional conservation sources (Prodan 1935; Sârbu et al. 2000; Dihoru and Negrean 2009). It is a perennial, psammophilous, xeromesophilous, and heliophilous species of nutrient-poor sandy soils. It frequently occurs with Medicago marina, Polygonum maritimum, Artemisia tschernieviana, Silene thymifolia, Stachys maritima, Salsola kali, Alyssum desertorum, Apera spica-venti subsp. maritima, Astragalus varius, Bromus tectorum, Centaurea arenaria subsp. borysthenica, Linaria genistifolia, Linum austriacum, and Plantago arenaria within psammophilous communities such as Aperetum maritimae and Festucetum arenicolae. The species flowers from June to August and is scientifically valuable due to its rarity. The main limiting factors are tourism development and the ruderalization of sandy vegetation. Because artificial population reinforcement may be difficult, the most important practical measure is to protect the beaches and dune sectors where the species still occurs. Fig. 13 shows the Perișor record and the mapped project distribution.

Eryngium maritimum L. is a typical coastal-dune species and is considered vulnerable or rare in Romanian conservation sources. Bibliographic records mention Grindul Chituc, Sulina, Letea, Caraorman, Sfântu Gheorghe, and Grindul Lupilor. The project dataset confirmed the species on the Sulina beach, where several tens of individuals were observed, but the population appeared to be in decline; it was also recorded in scattered populations at Sfântu Gheorghe, small populations on Grindul Lupilor, compact and numerous populations along the Sulina–Sfântu Gheorghe sector, and in the Periteașca–Perișor sector. Its broader geoelement is associated with the coastal sands of Europe up to approximately 60°N, including the shores of the Atlantic, Baltic, Mediterranean, Black Sea, and Caspian (Burduja 1954; Sârbu et al. 2000; Dihoru and Negrean 2009). The species grows on maritime dunes and in pioneer vegetation. It is a heliophilous perennial co-occurring with Centaurea arenaria subsp. borysthenica, Plantago arenaria, Secale sylvestre, Silene conica, Apera spica-venti subsp. maritima, Argusia sibirica, Artemisia tschernieviana, Bassia laniflora, Cakile maritima subsp. euxina, Euphorbia seguieriana, Festuca arenicola, Leymus racemosus subsp. sabulosus, and Salsola kali subsp. ruthenica. It flowers from June to September and has scientific and medicinal value. Threats include anthropisation, urbanisation, and insufficient protection. Conservation should maintain existing sites and may also use the species as an ornamental native plant in carefully managed beach facilities, without extracting it from natural populations. Fig. 14 shows representative plants and distribution points from the project dataset.

Stachys maritima Gouan is one of the rarest sandy-habitat specialists recorded in the project dataset. It is treated as critically endangered in the Romanian Red Book and as rare in other floristic sources. In the studied sector, it was found at Portița and Corbu, where the population is very small. Biogeographically, it is a Mediterranean-Black Sea coastal element. It grows on maritime sands together with Asparagus brachyphyllus, Ammophila arenaria subsp. arundinacea, Astrodaucus littoralis, Crambe maritima, Eryngium maritimum, Medicago marina, and Polygonum maritimum, within Elymion gigantei-type dune vegetation. Studies of psammophilous vegetation and rare coastal plants have also highlighted its rarity and localised distribution (Burduja 1954; Popescu and Sanda 1976; Sârbu et al. 2000; Dihoru and Negrean 2009). The project notes describe it as a perennial, thermophilous, and heliophilous plant of moderately moist, neutral, and nutrient-poor sandy soils, flowering from May to June. Its main conservation value is scientificbecause of its rarity. Fig. 15 illustrates the species and the Portița and Corbu project localities.

Limiting factors include a narrow habitat niche and limited long-distance dispersal. The population currently benefits from indirect protection provided by the fence separating the Portița resort from the area where it grows. Still, the small number of individuals makes collecting biological material risky. Any ex situ or reinforcement program should, where possible, rely on more robust populations outside the DDBR.

Limonium bellidifolium (Gouan) Dumort. is a rare halophilous species, treated as critically endangered in the Romanian Red Book and as subendemic or rare in other conservation sources. The project notes mention bibliographic records from Letea, Sfiștofca, Grindul Saele, Grindul Lupilor, and Caraorman. Field observations confirmed the species’ presence at Sfântu Gheorghe, Sacalin Island, Grindul Lupilor, Sulina, and Grindul Sărăturile, usually in small numbers. Its distribution is associated with the Black Sea and Mediterranean coasts, southern Russia, and eastern England, and it may be interpreted as an Atlantic-Mediterranean-Ponto-Caspian coastal element. Recent taxonomic and ecological discussions also treat Danube Delta populations under Limonium bellidifolium subsp. danubiale (Roman 1992; Drăgulescu 1998; Sârbu et al. 2000; Ciocârlan et al. 2013). The species is thermophilous and heliophilous, growing on moderately moist, neutral soils with moderate nitrogen content (Dihoru and Negrean 2009), especially in halophytic communities with Aeluropus littoralis, Artemisia santonicum, Halocnemum strobilaceum, Halimione verrucifera, Salicornia europaea, and Suaeda maritima. It is linked to Obionetum verruciferae, Salicornietum prostratae, and Puccinellion limosae-type vegetation. It flowers from July to August. Its conservation value is scientific, because of its restricted range and rarity. The main limiting factors are the overall reduction in suitable saline biotopes and the narrow ecological amplitude. Conservation should maintain existing habitats under effective protection and, where scientifically justified, consider translocation or population reinforcement only in sites with clear potential for natural expansion. Fig. 16 shows the Sfântu Gheorghe record and the mapped project distribution. We also checked the current nomenclature for this taxon against POWO (2026).

The coastal area is naturally dynamic. Erosion, storm action, overwash, sediment redistribution, wind transport, and temporal changes in humidity are part of the system’s normal functioning. These processes create open habitats and maintain the early successional stages many coastal plants require. Natural disturbance should therefore not be confused with degradation. Anthropogenic pressure becomes problematic when it intensifies disturbance, simplifies microhabitats, or prevents natural recovery. The project data identified several important pressures: uncontrolled tourism, circulation on dunes, vehicle access on sand, mechanical beach cleaning, grazing, trampling, waste deposition, ruderalization, local infrastructure, and habitat fragmentation. Similar pressures are discussed for Tulcea County habitats and for the coastal zone of the Danube Delta (Petrescu 2015; Strat 2016). International syntheses of sandy-beach ecosystems also emphasise the distinction between natural geomorphic disturbance and persistent anthropogenic pressure (Schlacher et al. 2007; Defeo et al. 2009).

Mechanical beach cleaning is especially relevant because it can remove seedlings, seeds, and organic material needed for pioneer vegetation to develop. While cleaning may be necessary in recreational sectors, it should be selective and should avoid natural beaches with rare species or embryonic dune vegetation. This precaution is consistent with broader evidence that intensive beach management can disrupt the biological and physical components of sandy-shore ecosystems (Defeo et al. 2009).

Grazing also requires careful interpretation. Moderate grazing may keep some grassland habitats open, but excessive grazing leads to compaction, nutrient enrichment, ruderalization, and the loss of sensitive plants. Similarly, tourist access is not necessarily damaging when it is guided and concentrated on resistant routes but becomes destructive when it spreads across dunes and rare-species microhabitats. More generally, international reviews identify recreation, tourism infrastructure, and motorized access as interacting sources of habitat loss, fragmentation, and disturbance on coasts (Davenport and Davenport 2006; Schlacher et al. 2007).

The most vulnerable situations occur where small, rare-plant populations coincide with accessible beaches, narrow dunes, or fragmented habitats. In such cases, even an apparently minor local disturbance can produce disproportionate conservation effects. Pressures were documented qualitatively through direct field observations, GPS records, and interpretation of imagery and were subsequently compared with published regional assessments. They were not measured through a controlled impact design or a uniform quantitative severity scale. Accordingly, they are treated as observed pressures and plausible management concerns, not as experimentally demonstrated causes of vegetation change.

The quantitative summaries reinforce this management interpretation: grazing-related pressure was mentioned in 88.3% of the species profiles, whereas tourism/development and mechanical beach disturbance were mentioned in 45.0% and 41.4%, respectively. The close Jaccard similarity between habitats 1310 and 1410 and between habitats 2110 and 2160 is consistent with a fine-scale coastal mosaic in which saline, dune, and shrub habitats meet within the same mapping squares. However, the high apparent habitat breadth of many species may partly result from assigning all habitats present in a square to the occurrence records within that square. The analysis therefore identifies conservation interfaces and monitoring priorities rather than strict ecological specialization. Table 4 summarises the principal pressures and corresponding recommended management responses. The central result is that conservation value is concentrated not only in individual rare-species locations but also at interfaces among habitat types. High overlap between 1310 and 1410 and between 2110 and 2160 should therefore be interpreted as evidence of a spatially interwoven coastal system. Management that treats each mapped habitat polygon in isolation may overlook the short environmental gradients, transitional zones, and disturbance regimes that permit specialised taxa to persist. At the same time, grid-square co-occurrence cannot demonstrate plot-level ecological affinity; the identified interfaces are hypotheses and priorities for targeted field verification.

The first management priority is to update the floristic and habitat inventory periodically. The 2009–2018 project dataset provides an essential baseline, but coastal systems change quickly. Repeated mapping should focus on rare-species locations, embryonic dune sectors, saline depressions, wet interdunes, and heavily visited beaches.

The second priority is microhabitat protection. Rare plants in the coastal area often depend on small-scale local conditions rather than on large, continuous habitat blocks. A small dune ridge, a moist hollow, a salt-affected patch, or an undisturbed upper beach may be critical for a local population. Manage such places as functional microrefugia or site-level conservation units.

The third priority is better visitor management. Natural beaches with vegetation may look less “clean” than mechanically maintained recreational beaches, but they are far more valuable ecologically. Information panels, guided routes, and communication with local tourism operators can reduce accidental damage and increase appreciation for coastal plants.

The fourth priority is combining in situ and ex situ conservation. In situ measures include protecting known populations, avoiding destructive interventions, and maintaining habitat processes. Ex situ measures may include seed collection, storage in germplasm banks, and cultivation in botanical gardens, especially for taxa with very small or declining populations.

This synthesis is based on surveys conducted between 2009 and 2018 and therefore provides a historical baseline rather than a current assessment of population status. Survey intensity was not uniform among years, seasons, and coastal sectors, and differences in detectability may have affected apparent occurrence and abundance. The descriptive design supports identifying spatial patterns and management hypotheses but does not, by itself, demonstrate causal relationships between pressures and vegetation change. Contemporary resurveys using a documented, repeatable design are needed to test persistence, trend, and management effectiveness. In addition, habitat affinities derived from shared grid-square identifiers may overestimate ecological breadth where several habitat types occur within the same square.

The authors have declared that no competing interests exist.

This study required no ethical approval because it is based on field observations of vascular plants, habitat records, and literature-derived information.

AI-assisted tools were used only for language polishing, editorial structuring, and formatting support. The authors reviewed, corrected, and approved all content and remain fully responsible for the scientific accuracy and integrity of the manuscript.

The field data synthesised in this article were generated within project PN 09 26 01 02, “Research on the flora and vegetation of the coastal area in the Danube Delta Biosphere Reserve,” conducted by the Danube Delta National Institute for Research and Development.

Mihai Doroftei led the manuscript synthesis, ecological interpretation, and writing. Silviu Covaliov contributed to spatial data processing, GIS interpretation, and figure preparation. Simona Dumitrița Chirilă and Florentina Tudose contributed to floristic and ecological interpretation, data organisation, literature checking, and manuscript revision. All authors reviewed and approved the final manuscript.

M. Doroftei https://orcid.org/0000-0002-8388-087X

S. Covaliov https://orcid.org/0000-0002-0412-4102

S.D. Chirilă https://orcid.org/0000-0003-3397-1834

F. Tudose https://orcid.org/0009-0009-6991-2247

The data supporting this study are available in internal reports and other unpublished literature. The dataset includes the harmonized vascular-plant checklist, vegetation associations, survey metadata, record provenance, conservation-status assignments, and generalized occurrence coordinates. Precise coordinates for the most sensitive threatened-plant populations are withheld from the public file. They may be made available for legitimate conservation or research purposes upon reasonable request to the corresponding author and with the agreement of DDNI.