Search Results (155)

Dehesas are mosaics of open grassland and standalone trees that are diversity reservoirs. However, they have recently faced abandonment and intensification, being replaced by plantations of fast-growing trees or subject to encroachment. Following a change in dehesa communities and structure, a change in soil microbial diversity and functionality in dehesas is expected, but dehesas’ microbial diversity is still a big unknown. In this work, we bring to light the soil prokaryotic taxonomic diversity in dehesa ecosystems and present a first approach to assessing their metabolic diversity through metabarcoding data. For this, we compared three dehesas dominated by different tree species: (i) one dehesa dominated by Quercus ilex; (ii) one dominated by Pinus pinea; and (iii) one dominated by a mixture of Q. ilex and Q. suber. At each dehesa, samples were taken under the canopy and in the open grassland, as well as through two seasons of peak vegetation productivity (autumn and spring). Our results show the following findings: (1) seasonality plays an important role in prokaryotic richness, showing higher values in autumn, and higher evenness in spring; (2) the effect of seasonality on the soil’s prokaryotic diversity is often modulated by the effect of tree species and canopy; (3) taxonomic diversity is driven mainly by the site effects, i.e., the opposite of the metabolic diversity that seemed to be driven by complex interactions among seasons, tree species, and canopies. Full article

One of the medicinal plants used in Ecuador that has the best prospects for industrialization is guayusa (Ilex guayusa Loes.). This review shows the potential of the species, analyzing the ethnobotanical aspects, ancestral uses, secondary metabolites, and research. The plant has been consumed for thousands of years by the high Amazonian peoples of Ecuador and currently forms part of the gardens of ancestral peoples and mestizo settlers. The most relevant secondary metabolites that have been investigated are xanthine alkaloids, terpenes, and phenolic compounds, while from the pharmacological point of view, the following uses stand out: physical and mental stimulants, analgesic, antioxidant, antimicrobial, anti-inflammatory, anti-diabetic, and phytohormonal. The goal of this review is to make known the benefits of guayusa, with the purpose of representing a resource that will provide benefits to the Amazonian inhabitants in the future. Full article

In recent years, severe decline and mortality events have been observed in holm oak (Quercus ilex L.) ecosystems in different Italian regions, including Puglia (southern Italy). Given the landscape and ecological relevance of holm oak forests in Apulia, a study was conducted to identify the causal agents related to this complex disease syndrome. The surveys, conducted in winter 2024 in three different woodlands, revealed the widespread occurrence of mature holm oak trees showing sudden death, crown thinning, shoot and branch dieback, sunken cankers, and root rot symptoms. Isolations performed from symptomatic samples collected from both stem and small roots yielded fungal and fungal-like colonies representing two distinct families: Botryosphaeriaceae and Peronosporaceae. Analysis of morphological and DNA sequence data allowed us to identify six distinct species, including Diplodia corticola and D. quercivora (Botryosphaeriaceae), Phytophthora cinnamomi, P. multivora, P. psychrophila, and P. asparagi (Peronosporaceae). For P. asparagi and P. psychrophila, isolated for the first time from declining holm oak trees in Italy, Koch’s postulates were satisfied by inoculating 1-year-old seedlings at the collar in controlled conditions. Thirty days after inoculation, all plants showed the same symptoms observed in the field. Overall, the data obtained highlights the co-occurrence of multiple Botryosphaeriaceae and Phytophthora species on declining holm oak trees and the discovery of a new haplotype of Diplodia quercivora. Full article

Understanding how regional and local climate variability drive radial growth in trees is necessary to assess the climate-warming mitigation potential of forests. However, tree species occurring in the same region differently respond to climate variability, including climate extremes such as droughts, depending on soil–moisture gradients (hydrological niche). We analyzed a tree-ring network built in a mountainous area (Sierra de Gredos, central Spain) to compare climate–growth responses between species and sites located along soil–moisture gradients. Tree-ring methods were applied to six tree species, and sampled in twelve sites, including conifers (Pinus pinaster) and broadleaves (Quercus pyrenaica, Quercus robur, Quercus ilex, Celtis australis, and Prunus lusitanica). Series of growth indices were correlated with climate variables and climate indices (NAO, North Atlantic Oscillation). The radial growth of most species was enhanced by high growing-season precipitation, linked to negative NAO phases. The influence of precipitation on growth variability strengthened as site elevation decreased, particularly in the case of C. australis and oak species. The topographical modulation of climate–growth couplings indicates that the hydrological niche drives species responses to water shortage. Tree-ring data could be used to refine time-dependent hydrological niches. Full article

In plants, the transition from the juvenile to adult stage involves physiological and anatomical changes initiated and partially controlled by evolutionarily conserved microRNAs. This process is of particular significance for the successful propagation of woody plant species that have transitioned to vegetative maturity and are recalcitrant to propagation. Conserved miRNAs differentially expressed between rejuvenated and mature Ilex paraguariensis plants were identified using high-throughput sequencing of small RNA libraries. The expression of miR156/miR157/miR528 was high in the leaves of juvenile plants and gradually decreased as the plant transitioned from juvenile to adult stages. In contrast, miR172 was predominantly expressed in adult plants. This variation confirmed that adults transitioned back to a juvenile phase after serial-rooted cuttings, allowing the plants to regain juvenile characteristics. Rejuvenation promotes the formation of adventitious roots and improves root structure, which supports the overall growth of the plant and results in greater vigour. The results will offer insights for further investigation into the molecular mechanisms regulating vegetative phase change in I. paraguariensis and other recalcitrant woody plant species. This knowledge could facilitate the earlier identification of rejuvenated material by analysing a wider range of genotypes and maturation stages, enhancing the efficiency of Ilex paraguariensis mass propagation. Full article

Acute Oak Decline (AOD) is a complex and rapidly progressing disease affecting several Quercus species across Europe. While previously reported in Quercus ilex in Italy, this study provides the first evidence of AOD symptoms and associated bacterial infection in Quercus coccifera (kermes oak). Symptomatic trees were identified in a Mediterranean forest in southern Italy, and bacterial isolation, qPCR detection, and 16S rRNA sequencing confirmed the presence of Brenneria goodwinii and Gibbsiella quercinecans. Phylogenetic analyses clustered the isolates closely with known AOD-related strains. Pathogenicity tests on excised Q. coccifera branches demonstrated that both bacteria induced wood necrosis and external exudates consistent with natural symptoms, confirming their virulence. These findings expand the known host range of AOD-related bacteria and highlight the potential threat to Mediterranean oak ecosystems. Early detection and monitoring of Q. coccifera decline are essential to inform conservation strategies and forest management practices aimed at mitigating AOD spread. Full article

Urban greenery is a key component of green infrastructure, contributing to environmental sustainability and urban well-being. Between 2019 and 2020, a comprehensive inventory of ornamental flora was conducted in Assemini (Sardinia, Italy), documenting 198 vascular plant taxa, including 155 exotic, 41 native, and 2 cryptogenic species from 65 families. Among the exotic species, most were neophytes (63%), and 14% were archaeophytes. In terms of life forms, scapose phanerophytes, with a tree-like growth habit, dominated (45%), while Mediterranean and American chorotypes were the most represented, each accounting for 21%. A total of 7356 plants were recorded, comprising trees (61.3%), shrubs (32.3%), and climbers (5.7%), belonging to 90 shrub, 89 tree, and 19 climber taxa. The highest number of plants was found in “Green Areas” and “Schools”, which also exhibited the greatest biodiversity, with 136 different taxa each. The most planted species were Quercus ilex, Nerium oleander, and Olea europaea. The survey also identified 21 allergenic, 36 toxic, and 35 mechanically harmful species, primarily located in “Green Areas” and “Schools”. Biodiversity analysis using the Shannon Index revealed significant diversity, with Fabaceae, Apocynaceae, and Fagaceae emerging as the most represented families. These findings highlight the importance of plant inventories in urban green space management for sustainable planning. Well-maintained green spaces can enhance ecological resilience, improve public health, and promote social cohesion in future urban developments. Full article

Moroccan vegetation faces significant pressure particularly from human activities and climate change, while most ecosystems lack detailed assessments. Phytoecological studies and species assessments are implemented using vegetation sampling, analysis of climate data, geological substrate maps, and the Digital Elevation Model (DEM). The study area hosts 565 plant species distributed into 74 families, with Asteraceae being the most abundant family, representing 17.7%. In addition, the correspondence analysis test demonstrates that species are grouped into six distinct blocks. Block 1 comprises a set of Quercus ilex forests. Block 2 encompasses Juniperus phoenicea lands and transition zones between Quercus ilex and Juniperus phoenicea. Block 3 represents Pinus halepensis forests and pine occurrences within Quercus ilex and Juniperus phoenicea stands. Block 4 indicates the emergence of xerophytic species alongside the aforementioned species; it forms the upper limits of Blocks 1, 2, and 3. Block 5 corresponds to formations dominated by Juniperus thurifera in association with xerophytes. Block 6 groups together a set of xerophytic species characteristic of high mountain environments. Additionally, Quercus ilex colonizes the subhumid zones and prefers limestone substrates, Juniperus phoenicea and Tetraclinis articulata, and Pinus halepensis occupies the hot part of the semi-arid in limestone, clays, and conglomerates, while the Juniperus thurifera and xerophytes inhabit the cold parts and limestone substrates. The thermo-Mediterranean vegetation level occupies low altitudes, dominated by Tetraclinis articulata, Juniperus phoenicea, and Olea europaea. The meso-Mediterranean level extends to intermediate altitudes, dominated by Quercus ilex and Juniperus phoenicea. While the supra-Mediterranean level is dominated by Quercus ilex, Arbutus unedo, and Cistus creticus. The mountain Mediterranean level, located in the high mountains, is dominated by Juniperus thurifera associated with xerophytes. Finally, the oro-Mediterranean level, found at extreme altitudes, is dominated by xerophytes. Some species within this region are endemic, rare, and threatened. Consequently, the implementation of effective conservation and protection policies is recommended. Full article

Oaks in the genus Quercus L. are keystone species in the forest ecosystem and are considered ideal models for the study of plant evolution. In this research, we applied population genetics, ecological niche analysis and phenotypic traits to explore patterns of species differentiation and demographic history of two Chinese montane oak species (Quercus baronii Skan and Quercus dolicholepis A. Camus) from Quercus section Ilex across species distribution ranges. Analyses of population genetics with ten nuclear microsatellite loci on 33 populations of the two oak species indicated great interspecific genetic variations with distinct genetic backgrounds for the two oaks. Simulations on species demography suggested a speciation-without-migration model as the best to explain species divergence, while an approximate Bayesian computation analysis indicated that the two studied oak species probably split at about 17.80–28.48 Ma. A comparison of two core bioclimatic factors and ecological niche tests revealed strong niche differentiation between the two oak species, and association analysis also found a significantly positive correlation between interspecific genetic variations and bioclimatic distances. Additionally, analyses of the leaf morphology of 117 specimens with five quantitative characteristics showed clear species discrepancy between Q. baronii and Q. dolicholepis. Based on this evidence from genetic, ecological and phenotypic analyses, our research indicated clear species differentiation between Q. baronii and Q. dolicholepis, possibly in relation to an early species divergence and varying adaptative features of the two oaks shaped by heterogeneous environments within Qinling-Daba Mountains and surroundings. This study provides an example for future investigation of species differentiation and evolution among related oak species with integrated analyses and highlights the importance of ecological conditions on adaptive evolution and genetic conservation of endemic tree species in montane regions. Full article

Wildfires, one of the most important ecological disturbances, influence the composition and dynamics of ecosystems all around the world. Changes in fire regimes brought on by climate change are making their effects worse by increasing the frequency and size of fires. This study examined the issue of delayed mortality at the species and community levels, concentrating on Mediterranean forests dominated by Quercus ilex and Quercus suber. This research examined areas lacking spectral recovery following a megafire, which, although relatively small compared to the total burned area, represented significant ecological disturbances. The results highlighted distinct post-fire dynamics at both the woodland and species levels. Q. ilex experienced higher delayed mortality, particularly in areas of lower fire severity (NR), likely due to increased intra-specific competition. Because of its thick bark, which offers stronger fire resistance and encourages regeneration even in high-severity fire zones (HR), Q. suber showed greater resilience. Responses from the shrub layer varied, and some species, such as Pteridium aquilinum and Cytisus villosus, showed post-fire proliferation. To improve our knowledge of ecosystem resilience and guide forest management in fire-prone areas, these findings highlight the intricacy of post-fire ecological processes and the need to integrate species-specific features with more general community-level patterns. Full article

Mediterranean forests are severely threatened by increasing seedling mortality due to harsh environmental conditions, especially drought. In this study, we investigate whether seedlings of Quercus ilex and Arbutus unedo, previously exposed to water deficit, acquired tolerance to summer drought. Seedlings of the two species were grown from April to September in a plastic tunnel greenhouse and exposed to two irrigation regimes (control, 100% water holding capacity; water-stressed, 50% of control). In mid-August, the irrigation of all plants was suspended for three weeks. The response of the species was analyzed to evaluate survival, growth, ecological, and anatomical traits of wood produced under stressful conditions and marked through the pinning technique. The results suggest that both species show pre-acclimation to drought, with Q. ilex demonstrating a marked increase in survival percentage. This is likely due to a reduction in vessel size in response to previous water stress. In contrast, in A. unedo, the higher frequency of narrower vessels allowed safer water transport compared to Q. ilex, thus explaining the slight increase in survival. Overall results indicated that the two species adopt different strategies to overcome drought, providing valuable insights for managing seedlings in natural ecosystems and urban green spaces. Full article

Invasive plants are among the top five drivers of biodiversity loss, primarily due to competition and allelopathy. By releasing root exudates, they alter soil properties, influencing both the abiotic and biotic characteristics of soil. The effects of invasive plants on soil characteristics and biota remain underexplored, with findings on this topic often being controversial and context-dependent. This study aimed to understand the impact of two invasive species—black locust (Robinia pseudoacacia L.) and tree of heaven (Ailanthus altissima Mill.)—on soil abiotic characteristics, microbial and Collembola communities. Comparisons were made with soils under two types of native vegetation cover: holm oak (Quercus ilex L.) and herbaceous vegetation. In fall 2023, twelve sites within Vesuvius National Park (three per plant cover type) were sampled to assess soil characteristics, microbial biomass and activities, and Collembola communities. Tree of heaven increased soil pH (6.95), bacterial biomass (42.94 ng g⁻¹) and Collembola density (2038 organisms m²) while reducing water content (10.6% d.w.) and organic carbon (1.21% d.w.). Black locust increased nitrogen content (0.70% d.w.) but reduced microbial biomass (22.85 ng g⁻¹) and Collembola density (873 organisms m²). Tree of heaven soils showed a higher proportion of hemi-edaphic Collembola (48.3%) compared to black locust soils, which were dominated by eu-edaphic forms (42.2%). Despite these differences, Collembola species composition was poorly diversified under invasive plants, with Brachystomella parvula and Protaphorura armata dominating both types of cover. In conclusion, the presence of invasive plants was associated with declines in soil organism biodiversity, underscoring their disruptive influence on forest ecosystems. Full article

Cosmopolitan in the western areas of Europe as well as on other continents, the Ilex genus is interesting for its genetic, phenotypic, and biogeographic variabilities. Its insular/local distribution, according to existing data on the periphery of the central and southern European areas, represents a suitable case study with reference to the adaptive plasticity or acclimatization of the Ilex aquifolium L. species to new climatic conditions. The aim of the present study was to analyze the genetic variability at the genome level in four insular populations of Ilex aquifolium L., i.e., in three spontaneous populations from Romania (RO), Serbia (SR), and Bulgaria (BG) and a cultivated population from Hungary (HU). According to the obtained results, the most genetically similar populations among the four considered in this study were those from SR and RO. Genetic variation overlapped genes that were generally associated with metabolic regulation/transport factors, water, and abiotic stress factors. The analysis of single-nucleotide polymorphisms (SNPs) at the levels of the chloroplast and mitochondrion, from the point of view of their distributions at the gene level, identified two clusters: one that includes the native populations (BG, SR, and RO) and a second one including the cultured population from HU. Full article

Plants belonging to the Ilex species are distinguished by their rich composition of diverse phenolic compounds and various bioactive substances, which demonstrate dual functionalities in therapeutic applications and health promotion. In recent years, these plants have garnered significant interest among researchers. While the application scope of plant polyphenols (PPs) is extensive, the exploration and utilization of holly polyphenols (HPs) remain comparatively underexplored. This article reviews the research advancements regarding the predominant phenolic compounds present in commonly studied Ilex species over the past five years and summarizes the application studies of PPs across various domains, including pharmacological applications, food technology, health supplements, and cosmetic formulations. The objective of this review is to provide insights into the systematic research and development of HPs, offering references and recommendations to enhance their value. Full article

Acorns, the seeds of oak trees, are pivotal in the Mediterranean region, historically serving as vital sustenance for wildlife and humans. Although traditionally used for livestock, in times of scarcity, acorns were also used in human diets together with their use in traditional medicine. In this review, we explore and deepen the multifaceted significance of oak species, consolidating nutritional data while emphasizing sustainable practices for modern dietary integration and potential applications in other areas, promoting long-term ecological balance. In the Mediterranean region, notable species are Quercus ilex, Q. faginea, Q. suber, and Q. coccifera, which differ in flavor, texture, and nutritional content. Rich in carbohydrates, acorns can contain up to 50% starch as well as amino acids, proteins, and lipids. This nutritional composition favors the preparation of flour for use in bread doughs or even diverse types of processing such as roasting, which makes it a substitute for coffee. Furthermore, acorn by-products, containing tannins, find applications in leather processing. This review highlights and summarizes in detail the nutritional potential, culinary adaptability, and diverse applications of acorns, emphasizing the need to preserve and utilize natural resources sustainably. In doing so, it sheds light on the often-overlooked value of these humble seeds. Full article