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Coastal dunes are unique ecosystems distributed worldwide. They share coastline-to-inland abiotic stress gradients determining their plant´s spatial distribution and biological interactions. Ambrosia chamissonis and Ammophila arenaria dominate coastal dunes in Chile, but there is scarce ecological information about their interactions and spatial distribution. The aim of this study was to characterize the coexistence of these two species and to evaluate the effect of stress gradients on their spatial distribution and performance. The study was carried out in three coastal dunes of the Ñuble Region, Chile; two dunes in which each species dominates and one in which they coexist. In each dune, sampling sites were defined along study transects perpendicular to the coast, where both soil characteristics (pH, salinity, contents of water, organic matter, nitrogen, phosphorus, and potassium) and biological variables of each species (cover, height, water content, content of foliar macronutrients) were measured. Variation of each abiotic variable with the distance from the high tide level was correlated to determine environmental stress gradients. A Canonical Correspondence Analysis (CCA) was performed to determine soils characteristics that better explained changes in plant abundance. The Relative Interaction Intensity index was calculated from biological variables and compared intraspecifically to determine dominant interactions along the dunes. Our results showed two soil stress gradients (soil salinity and available potassium) which decreased inland and may define in part, the spatial distribution of the species, as shown by the CCA. Our results support the idea that dune plants do not always follow the stress gradient hypothesis suggesting a modification of the hypothesis.

To demonstrate possible community selection on seed size, a time-series analysis of cover data from 236 Danish grassland sites was performed in a linear model. Across four grassland habitat types and during an eight-year period, there was a significant decline in large-seeded species. Therefore, it was not possible to corroborate the initial hypothesis that a historical increase in nitrogen deposition and the observed vegetation changes towards taller and more competitive plant species favored plant species with large seeds. In the analysis, the continuous seed size variable was used to group plant species into functional types. This method was chosen in order to account for the sampling process of the cover data and is in contrast to most other analyses of trait selection, where the community weighted mean of the traits is used as the dependent variable.

Vascular epiphytes are plants that grow on phorophytes, and their distribution may vary both horizontally and vertically. Understanding the factors shaping epiphyte distribution and their relationship with alpha and beta diversities is crucial for understanding richness and composition patterns. We investigated alpha and beta diversity variation in the vertical and horizontal stratification of epiphyte communities across different vegetation types in a dwarf cloud forest. Twenty-four 20 × 10 m plots were established in three vegetation types defined by distinct soil characteristics, different phorophyte height and differences in tree species composition in Parque Estadual do Ibitipoca, Minas Gerais, Brazil. Phorophytes were divided into four strata: (A) base of the trunk, (B) lower trunk, (C) inner canopy, and (D) outer canopy. Alpha and beta diversity analyses were performed for each site. We found a reduced stratification in the area, indicating minimal composition differences between the strata. However, the canopy exhibited greater species richness than the trunk. Vegetation types F1 and F2 displayed higher richness compared to F3. Orchidaceae was the richest family overall, while Bromeliaceae and Polypodiaceae were more frequent. Holoepiphytes were highly representative, demonstrating consistent patterns of richness, composition, and dispersion, with anemochorous species being the most abundant. This study highlights the unique patterns of epiphyte stratification, emphasizing the importance of biotic and abiotic characteristics in colonization processes. Despite the low canopy of the forest, the non-uniformity in stratification demonstrates that formation characteristics, such as height, play a significant role in shaping epiphyte richness and composition patterns.

Fritillaria has important medicinal and horticultural values. This research aims to comprehensively assess the taxonomic relevance of micro-anatomical features within ten species belonging to Fritillaria subgenus Fritillaria, namely F. aurea, F. bithynica, F. crassifolia, F. enginiana, F. glaucoviridis, F. kittaniae, F. serpenticola, F. sibthorpiana, F. wendelboi, and F. whittallii, utilizing light microscopy. The majority of these species exhibit endemism within the Turkish Mediterranean Region, with F. aurea and F. crassifolia representing endemic Irano-Turanian elements, while the rest are native to the Eastern Mediterranean Region. In this anatomical investigation, we described and compare the cross-sections of the stem and leaves. Results revealed substantial variation in anatomical traits among the studied species. The presence or absence of eglandular trichomes, crystal granules in the leaf surface and cross section and in stem pith region, and the arrangement of parenchymal and sclerenchymal layers in the stem offered useful taxonomic markers. Similarly, leaf characteristics such as epidermal cell sizes, stomatal indices, mesophyll types, and guard cell shapes provided distinguishing features. A dichotomous key was developed based on these anatomical traits to aid in the accurate identification of Fritillaria species, highlighting the practical utility of these features in taxonomic studies. The findings underscore the importance of micro-anatomical traits as valuable tools for distinguishing and classifying plant species, especially in cases where morphological traits alone may not provide sufficient differentiation.

Melpomene peruviana is one of the ecologically toughest fern species that prospers under climatically extreme conditions between 3400-5200 meters above sea level and occasionally in dry areas at lower elevations. To gain a better understanding of the adaptations that allow this species to withstand such extreme environmental conditions, we investigated the anatomy and histochemistry of the sporophyte of three populations of M. peruviana. All plant organs exhibited thick cuticles, and vascular bundles surrounded by a ring or cap of sclereids and suberized endodermis. Roots also showed an exodermis with U-shaped thickening. The sclereids and the chlorenchyma of the leaf mesophyll were rich in phenolic compounds. Tannins were detected in the spongy parenchyma close to the vascular bundles of the leaf. Hydathodes revealed a cutinized endodermal layer and the presence of flavonoids, lipidic/terpenoid droplets, and free sugars in the epidermis and parenchyma cells. Rhizome scales had basal idioblasts and apical clavate glands with complex contents rich in phenolic compounds, lipids, terpenes, mucilaginous polysaccharides and proteins. Some of the observed morpho-anatomical characteristics such as microphylly, small stomata in high densities, thick cuticles and sclerenchyma close to the vascular tissue, reduce water loss by evapotranspiration and correspond to typical xeromorphic fern features. Among the histochemical characteristics, mucilaginous polysaccharides may act as gels to absorb and retain water while phenolic compounds are recognized for their antioxidant activity. The three populations exhibited a remarkable uniformity concerning their histochemical assays, stomatal dimensions and densities, and tissue thickness. The anatomy and histochemistry of M. peruviana are described for the first time, highlighting morphoanatomical and histochemical characteristics that act as key adaptations to xeric environmental conditions.

Floral traits are influenced by elevation in various species, but no information is available for the Coffea canephora and C. arabica. It was hypothesized that: 1) number of stamens and petals can vary depending on the species and genotype within the same species; 2) variations in the morphological traits occur in response to the difference in elevation, 3) greater variability in flower morphology among C. canephora genotypes is expressed at high- than at low-elevation, due to environmental pressure, and 4) the changes in floral morphology due to alterations in elevation are more pronounced in C. canephora than in C. arabica. This study aimed to investigate the G × E interaction for morphological traits of coffee flowers and, based in genetic parameters estimation, explore the potential use of these traits in breeding programs. Experiment comprised of coffee plantations under full sun of both species at two elevations. The number of petals and stamens varied between five and six in C. canephora. At two elevations, Beira Rio 8 (C. canephora) genotype stood out for presenting the highest averages for all size traits related to corolla, and stigmatic lobes. The variability in floral morphology among C. canephora genotypes was not greater at high- than at low- elevation. Overall, flower size of all studied C. canephora and C. arabica genotypes was larger at low- than at high-elevation, but the stigmatic lobes length, the ratio between stigmatic lobe length and style length, and partially the ratio between anther length and stamen length were greater at high-elevation. C. arabica flowers were smaller and mostly irresponsive to elevation, in contrast with C. canephora flowers. There was a significant genotype by environment interaction for seven out of the nine traits, with a predominance of complex-type interactions. Conducting studies on morphological traits of flowers at a greater number of environments with distinct elevations can provide better insights into the potential use of these traits in studies of adaptability and stability of Coffea spp. genotypes to different environmental conditions, contributing to genetic improvement efforts to achieve resilience of coffee cultivation in the scenarios of climate change.

Plants with specialized pollination systems may be susceptible to reproductive failure when pollinator service is unpredictable. This can influence the selection of floral traits that promote outcrossing in the presence of pollinators and selfing in their absence. Limited evidence exists regarding the association between specialized pollination and reproductive assurance, necessitating further investigation. We studied the reproductive biology of Dianthus inoxianus, a rare Mediterranean carnation endemic to a semi-arid region in SW Spain. D. inoxianus exhibited protandrus flowers and additional phenotypic signs of specialization for nocturnal pollination. Nectar sugar concentration remains relatively constant throughout the day (average 33.4%), while the standing crop varies considerably (average 1.5 μL/flower), peaking in the late afternoon and early evening. Controlled hand pollinations revealed that D. inoxianus is fully self-compatible, with similar reproductive success in autogamous, geitonogamous, and allogamous crosses. However, a small proportion of bagged flowers exhibited autonomous selfing. To assess the impact of presumed nocturnal pollination, we studied reproductive fitness and flower visitors over five years in three populations. Over 210 h of pollinator censuses, the hawkmoth species Hyles livornica and Macroglossum stellatarum, which were mainly dusk-active, accounted for > 95% of flower visits. Fruit and seed set positively correlated with hawkmoth visitation rate across years and populations. Additionally, pollinator exclusion experiments demonstrated that reproduction relies predominantly on nocturnal pollinators. However, under natural conditions, D. inoxianus also showed a non-negligible degree of autonomous self-pollination, with fruit- and seed-set being equivalent in absence of pollinators or under diurnal pollinators. We found evidence of an ecologically specialized pollination system and capacity for autonomous selfing, a combination that may enable the persistence of this taxon in a markedly unpredictable pollination environment.

Climate change in alpine habitats has a direct impact on vascular plant species, and is leading to changes in species abundance and distribution. Alpine plant communities are expected to experience a turnover of species over time, due to the loss of cold-adapted specialists and the upslope migration of more thermophilic taxa. Therefore, assessments of single species changes are important for research and conservation. Here, we propose a new analysis protocol for the GLORIA (GLobal Observation Research Initiative in Alpine environments) network, and potentially, for other monitoring programmes capable of defining winning and losing plant species. The proposed approach involves the non-parametric Cliff's ‘Delta’ measure of ‘effect size’, which provides a measure of the intensity of species abundance changes over time and is applicable for vegetation data collected using both re-visitation and long-term monitoring approaches. Compared to other methods, Cliff's ‘Delta’ was more conservative and efficient in detecting winning/losing taxa, as well as being suitable to analyse data of rare species with few records. To test the effectivity of the Cliff ‘Delta’ method, we analysed the vegetation data from three Italian GLORIA sites. We investigated 413 vascular plant species and found a total of 41 winning and 24 losing species. Moreover, we used Cliff ‘Delta’ to assess whether plant assemblages are responding differently among sites and plant growth forms. Our findings showed that alpine plant communities are changing faster on Apennines sites and that growth form types respond differently across the study sites.