Folia Oecologica Feed

Salicylic acid-mediated salt tolerance in date palms: comparative analysis of application methods

Wed, 30 Sep 2026 00:00:00 GMT

In arid environments, tree growth and ecosystem function are limited by salinity stress. Herein, we describe the role of salicylic acid (SA) in ameliorating salt tolerance in date palms (Phoenix dactylifera L., cv. Sayer), a woody species characteristic of arid, salinized environments. We examined the role of salicylic acid (SA) delivered via trunk injection and foliar treatment in the tree’s physiological acclimatization strategy. Trunk injection of SA at 200 ppm resulted in the highest plant height. SA treatments were associated with increased antioxidant activities (peroxidase and superoxide dismutase), decreased malondialdehyde, and fine-tuned hormone homeostasis (increased auxin and decreased abscisic acid). The trunk injection has much higher efficacy, providing important insights into the adaptation mechanisms of the tree and the efficacy of bioactive compound delivery from the injection site. Our results have implications for tree survival in increasingly salinized arid systems, and together, these findings represent progress toward a mechanistic understanding of ecophysiological pathways of adaptation to environmental stress in trees.

Assessing the impact of copper oxide nanoparticles on growth attributes and regenerative potential in date palm (Phoenix dactylifera) micropropagation

Wed, 30 Sep 2026 00:00:00 GMT

Copper oxide nanoparticles (CuO-NPs; 0–40 mg L–1) were applied in MS medium to evaluate microbial contamination, shoot regeneration, and multiplication in date palm (Phoenix dactylifera L. cv. Barhee). Compared to the untreated control (0 mg L–1), copper oxide nanoparticles at 10 mg L–1 eliminated microbial contamination without phytotoxicity, yielding the highest regeneration frequency (88.60%) and maximum shoot number (14.25 shoots jar–1), whereas 40 mg L–1 caused 21.6% culture mortality. Supplementation with 10 mg L–1 CuO-NPs significantly increased shoot nutrient accumulation (N, P, K, Fe, Zn, Cu) relative to the control and other treatments (p ≤ 0.05). Antioxidant enzyme activities (SOD, CAT, POD), total soluble carbohydrates (152.10 mg g–1 DW), and free amino acids (8.05 mg g–1 DW) reached maximum values at 10 mg L–1, compared to the control, whereas soluble protein declined to 10.40 mg g–1 DW at 40 mg L–1, dropping below the untreated control. Root induction was highest at 10 mg L–1 CuO-NPs, while higher concentrations (≥ 20 mg L–1) suppressed rooting and induced root cellular modifications compared to the control. Plantlets derived from the 10 mg L–1 CuO-NPs treatment achieved the highest ex vitro acclimatization survival rate (88%). Genetic fidelity analysis using monomorphic RAPD and ISSR markers confirmed genetic stability among regenerated plantlets relative to mother plants and control cultures.

Geospatial modelling of widely distributed oriental-beech forests syntaxa in the Northwestern Caucasus

Wed, 30 Sep 2026 00:00:00 GMT

For the first time in the Northwestern Caucasus, we applied the maximum entropy method (MaxEnt) to estimate the potential distribution of widespread oriental-beech forest syntaxa belonging to the alliance Myosotido dissitiflorae–Fagion orientalis Shevchenko et al. 2026. The models demonstrated good performance (AUC = 0.85–0.95) with variables characterizing precipitation, temperature, and altitude. Maps were constructed, and potential distribution areas of oriental-beech forests in the region were identified. The most significant bioclimatic predictors in the models of all studied syntaxa were found to be precipitation seasonality and annual precipitation. The potential distribution area of oriental-beech forest syntaxa was found to encompass the foothill, mid-mountain, and high-mountain zones of the central and eastern parts of the Northwestern Caucasus, with the exception of the western part of the region and the Black Sea coast, where these syntaxa are found only locally in well-watered mesorelief conditions. Geospatial modelling revealed significant similarities between oriental-beech and hornbeam forests in terms of their growing conditions in the Northwestern Caucasus. Therefore, the oriental-beech and hornbeam forests of the Northwestern Caucasus can be considered as mosaic elements within the oligo- or polydominant stands of broadleaf forests in the region. The resulting models of the potential distribution of oriental-beech forests can be used in geobotanical mapping, forest vegetation inventories, and clarification of syntaxa distribution boundaries in the Northwestern Caucasus and Northwestern Transcaucasia. The obtained results are essential for informed conservation planning and sustainable use of the region’s unique oriental-beech forests, rich in endemic animal and plant species, under conditions of modern anthropogenic impact.

Predicting forest biodiversity from spaceborne GEDI LiDAR and machine learning: structural drivers and regional transferability across Pacific Northwest forests

Wed, 30 Sep 2026 00:00:00 GMT

Remote sensing offers important opportunities for large-scale biodiversity monitoring, yet the capacity of spaceborne laser scanning to predict forest biodiversity remains insufficiently understood. This study evaluates relationships between forest structural complexity and tree species diversity using data from the GEDI mission. Structural metrics describing canopy height, vegetation density and vertical foliage distribution were linked to ground-based forest inventory data from 9,692 plots across the Pacific Northwest region of the United States. Tree biodiversity was quantified using species richness and two diversity indices. Structural complexity showed consistent positive relationships with biodiversity, with vegetation density and vertical foliage heterogeneity outperforming maximum canopy height as predictors. Machine-learning models explained approximately 17–22% of biodiversity variation under standard cross-validation. In contrast, spatial cross-validation revealed strong reductions in predictive performance, indicating limited geographic transferability. Including broad-scale climate variables produced modest improvements, while regionally calibrated models substantially increased accuracy, achieving up to 40% explained variance for species richness. Overall, the results demonstrate that spaceborne laser-derived forest structure contains meaningful biodiversity information, but effective large-area application requires regional calibration to account for spatial variation in forest composition and environmental conditions.

Climate sensitivity of Norway spruce inferred from blue intensity and tree-ring width

Wed, 30 Sep 2026 00:00:00 GMT

In high-mountain Norway spruce stands, contrasting tree health and strong within site growth divergence may alter climate sensitivity and obscure climate reconstructions when trees are analysed together. We tested whether blue intensity (BI) chronologies, developed for all trees or separately by health status, provide stronger climatic signals than tree-ring width (TRW) chronologies. We established 12 plots and sampled neighbouring canopy trees of similar size and social position but contrasting health status (healthy vs. declining or dead). High resolution tree-ring images were used to develop indexed TRW and BI chronologies and assess their temperature sensitivity. During 1961–1990, BI showed stronger correlations with temperature than TRW, whereas in recent period 1991–2022 TRW became more strongly related to temperature in healthy trees. In declining or dead trees, BI retained a stronger temperature signal than TRW. These findings indicate that tree health and recent warming may alter the climate-growth relationships and that BI and TRW provide complementary information for climate reconstruction.

Species-specific physiological responses of four sympatric Quercus species to water deficit during seedling establishment

Wed, 30 Sep 2026 00:00:00 GMT

Climate change projections for Southeast Europe indicate increasing temperatures and more frequent and severe summer droughts, raising concerns about the success of oak regeneration during early developmental stages. This study aimed to compare the drought responses of four sympatric oak species (Quercus petraea, Q. cerris, Q. frainetto, and Q. pubescens) during the early developmental stage after seedling establishment under severe water deficit. Seedlings were grown from acorns collected in Serbia and exposed to semi-controlled glasshouse conditions. Water deficit was induced rapidly by withholding irrigation for three weeks without a subsequent recovery period. Physiological responses were monitored through repeated measurements of stomatal conductance – gsw and quantum efficiency in light – PhiPS2, while seedling vitality was evaluated at the end of the experiment. Linear mixed-effects models were used to evaluate the effects of water deficit duration, oak species, treatment, and time of day. The results demonstrated clear interspecific differences in physiological responses to water deficit. Across species, reductions in gsw generally preceded declines in PhiPS2, indicating that stomatal regulation represented an earlier response to decreasing water availability than photochemical efficiency. Q. cerris exhibited the earliest phytological response and the greatest decline in vitality under the imposed experimental conditions. In contrast, Q. frainetto maintained higher PhiPS2 and delayed stress responses throughout the experiment. Q. petraea and Q. pubescens showed intermediate and similar physiological responses, maintaining relatively stable gsw during the first two weeks before a marked decline. These findings improve our understanding of species-specific drought strategies during the critical establishment phase and provide insights relevant for predicting natural regeneration dynamics of southeastern European oaks under future climate scenarios.

Tree cover, understory complexity and heaps shape fine-scale microhabitat partitioning in sympatric rodents

Wed, 30 Sep 2026 00:00:00 GMT

Habitat heterogeneity promotes species coexistence by increasing opportunities for niche differentiation. Temperate forest small mammals provide an excellent model for investigating how fine-scale habitat structure influences spatial segregation. In this study, we examined fine-scale microhabitat associations of sympatric forest rodents, Clethrionomys glareolus and Apodemus spp., within a heterogeneous deciduous woodland in central Italy. We reanalysed a historical dataset using contemporary statistical approaches to assess habitat associations, based on a 289-trap grid (2-m spacing, 12 days) and 20 additional traps monitored for 23 days in woody debris heaps and control plots. A total of 176 individuals of Apodemus spp. and 65 of C. glareolus were captured within the trapping grid, whereas C. glareolus was recorded near heaps significantly more frequently (49.1%, n = 57 captures) than Apodemus spp. (32.8%, n = 116). Multivariate ordination (RDA), GLMMs and GLMs consistently identified vegetation structural complexity as the main driver of habitat segregation. Clethrionomys glareolus was associated with woody debris heaps and higher tree cover, whereas Apodemus spp. preferred herb-rich, open understory habitats and occurred significantly less frequently near heaps. Independent evidence from the spatial distribution of the asp viper (Vipera aspis), the principal ambush predator of both rodents, further indicated that heaps function as focal microhabitats, with nearly 90% of recently fed vipers recorded within 5 m of these structures. These results support the hypothesis that fine-scale habitat heterogeneity promotes coexistence by reducing spatial niche overlap. Maintaining structural complexity, including woody debris and heterogeneous understory layers, may therefore contribute to sustaining small mammal diversity in Mediterranean forest ecosystems.

Donkioporia expansa (Fungi, Basidiomycota), an indoor wood destroyer, is also a prominent species of thermophilic old-growth forests with oak

Wed, 30 Sep 2026 00:00:00 GMT

The study deals with a rare polypore Donkioporia expansa and environmental parameters of its habitats, primarily using data from newly discovered sites in Slovakia and Czechia. This species prefers either thermophilic forests of lower altitudes, with dominant Sessile oak (Quercus petraea) or Turkey oak (Quercus cerris), or steep, sun-exposed slopes situated at higher elevations (350–676 m). All records in nature are from old-growth forests and oak wood in advanced initial to moderate decay stages. The occurrences in buildings are secondary; the fungus was likely introduced there either in construction timber or via spores. The growth conditions of D. expansa mycelium and basidiomata are summarized. Despite the increase of the number of recent localities and records, the species is rare and deserves both inclusion in Red Lists and protection. Its survival in most localities is ensured because most of them are in nature reserves.

Marker- and genomics-assisted assessments over three decades across Europe reveal substantial genetic diversity and adaptive potential in pedunculate oak (Quercus robur L.), informing operational conservation strategies

Wed, 30 Sep 2026 00:00:00 GMT

This review synthesizes three decades of molecular evidence on the genetic diversity and conservation of pedunculate oak (Quercus robur L.) across Europe. A methodological synthesis delineates three phases of marker evolution: Phase I (1993–2003) – isozymes, RAPD, AFLP and early SSRs establishing population-genetic baselines; Phase II (2004-2014) – multi-marker integration and QTL analyses linking marker variation to adaptive traits; and Phase III (2015–2026) – the genomic era with WGS, SNP, ddRADseq and GBS systems enabling high-resolution inference of demography and local adaptation. Genetic diversity of Q. robur was assessed using allelic richness, observed and expected heterozygosity, fixation and differentiation indices, chloroplast haplotype diversity and SNP-based genomic metrics, consistently showing high within-population diversity, low but significant among-population differentiation maintained by extensive gene flow and spatially structured adaptive variation shaped by postglacial history and environmental gradients, confirming strong evolutionary and adaptive capacity across Europe. Integrating SSR, SNP and phenotypic evidence reveals robust adaptive potential to drought and water stress. Based on these findings and EUFORGEN guidance, a tiered conservation strategy is proposed: (i) in situ preservation of large, interbreeding stands; (ii) provenance-based seed transfer within seed zones; (iii) ex situ conservation of marginal populations; and (iv) circa situm management in productive landscapes. This synthesis establishes a marker-informed framework linking evolutionary processes to actionable conservation, thereby strengthening the adaptive capacity of Q. robur under climate change across Europe.

Ecological assessment of an unprotected natural forest area in São Miguel Island (Azores) and its potential conservation value

Sun, 31 May 2026 00:00:00 GMT

Relevant habitats occurring outside protected areas act as buffers for nearby reserves and provide valuable ecosystem services. In the Azores, 24% of the land is protected, but important biodiversity areas remain outside these boundaries. In this study, we assessed an area adjacent to São Miguel Island Natural Park, classified as natural vegetation. Plant and bird species were listed, 5 × 5 m plots used to characterise the plant communities and indicator species. Dendrometry approaches were used to study the invasive dynamics of Clethra arborea. Results exhibited two different plant communities: a Laurus azorica forest invaded by C. arborea; and a Calluna vulgaris scrubland with a rich herbaceous layer. Both communities reflected past human disturbances, possibly linked with collection of top-soil as substrate for pineapple cultivation. The results also confirmed that relevant areas for biodiversity exist outside protected areas in the Azores, and if restored, can potentially support biodiversity conservation.

Climate change impacts on the distribution of deciduous forests in the Central Highlands of Vietnam

Sun, 31 May 2026 00:00:00 GMT

The spatial distribution of deciduous forests (DF) in Vietnam is relatively restricted. However, these ecosystems play a pivotal role in overall ecosystem structure and function. This study aimed to assess the environmental drivers governing the distribution of DF in Vietnam under climate change scenarios. Our results show that DF currently occupies a relatively narrow climatic niche spanning approximately 10,496.49 km2, predominantly in the Central Highlands. Precipitation of the driest month, temperature seasonality, and elevation emerged as the dominant predictors of DF distribution. Projected climatic niche contraction for the period 2081–2100 ranged from 7.6% (SSP245) to 33.2% of the current climatically suitable area (SSP585). This decline is primarily associated with increased precipitation during the coldest quarter and greater temperature variability. These findings underscore the need for targeted and proactive conservation strategies for DF in the Central Highlands of Vietnam, where the already limited suitable habitats are particularly susceptible to climate-driven range contractions.

A probabilistic habitat–suitability overlap framework (HMI) reveals spatial bias in MaxEnt models of West African forest butterflies

Sun, 31 May 2026 00:00:00 GMT

Species distribution models (SDMs) are widely used to infer potential species ranges, yet their ecological reliability in rapidly transformed landscapes remains poorly understood. We applied Maximum Entropy (MaxEnt) modelling to estimate the potential distribution of twelve forest-specialist butterfly species of high commercial value across West Africa, with a focus on Côte d’Ivoire, Ghana and Liberia, based on bioclimatic covariates. Models showed good predicted performance (mean jackknife AUC = 0.854, significantly better than random; null model test p < 0.01), driven by both precipitation-related variables (i.e. precipitation seasonality; 57.4% of explained variance in model predictions) and temperature-related variables (annual mean temperature, 33%). However, spatial predictions showed limited concordance with contemporary forest cover: 45.23% in Liberia but only 4.69% in Cote d’Ivoire and 6.42% in Ghana. Key refugia such as Taï Forest (Cote d’Ivoire) were partially underpredicted. To evaluate whether the observed agreement between predicted habitat suitability and forest cover reflects genuine ecological associations or is instead driven by spatial bias, we developed a probabilistic framework in which the expected overlap is defined as the product of forest availability and suitability probability. Building on this null expectation, we derived a Habitat Matching Index (HMI), expressed as the ratio between observed and expected overlap, allowing us to quantify deviations from random spatial association and to distinguish ecological signal from patterns generated by habitat availability alone. HMI values differed markedly among countries (Côte d’Ivoire: 0.319; Ghana: 0.570; Liberia: 1.407), demonstrating that apparent model performance is strongly influenced by forest extent rather than ecological fidelity alone. These findings reveal a fundamental limitation of climate-based SDMs: high statistical accuracy does not necessarily imply ecological realism. Integrating habitat availability into model evaluation provides a critical correction, improving inference in heterogeneous and rapidly changing tropical landscapes. We advocate combining climatic, land-cover, and species-specific data to enhance SDM reliability in conservation biogeography.

Status and development trends of Scots pine plantations outside the species areal in Bulgaria

Sun, 31 May 2026 00:00:00 GMT

Our study attempted to find a spatial analogue of the anticipated climate change in present times by investigating the status and development trends of four half-century-old man-made Scots pine stands outside the species areal in Central and North-Eastern Bulgarian lowlands. Stand composition, competition intensity, stand stability, site quality, tree mortality and ecosystem fit according to nationally established standards, were evaluated and growth correlations with climatic variables were analysed. Two stands experiencing an ongoing dieback were distinguished, regardless of the good productivity potential of the trees (Stand 2) or the low competition pressure and good mechanical stability maintained (Stand 1). The other 2 plantations showed either no mortality (Stand 4) or mortality due to self-thinning (Stand 3), forming a relatively productive and dense pure Scots pine stand (Stand 4) or a mixed, highly productive stand with diverse composition and good structure and stability (Stand 3). Tree growth was positively affected by the summer and the annual precipitation amounts, while negative correlation was found with the summer heat moisture index. Our investigation revealed that pine growth still can be sustained even in a slightly humid climate, if a high productivity level and good stand structure are assured, that indicates the overall capability of the species to adapt. However, the Scots pine trees are not able to adapt to relatively dry environmental conditions, suitable for lowland thermophilic species such as oaks, where the stands collapse when the heat-moisture balance worsens.

Apical shoot propagation of Taxus wallichiana Zucc. in Vietnam: a conservation-oriented approach to overcome the limitations of lateral cuttings

Sun, 31 May 2026 00:00:00 GMT

Taxus wallichiana Zucc. is an endangered medicinal tree species valued for its production of paclitaxel, but its conservation is constrained by overexploitation and poor natural regeneration. This study evaluated the feasibility of propagating T. wallichiana by apical cuttings under nursery conditions as a conservation-oriented alternative to seed propagation and lateral cuttings. Two-year-old donor plants subjected to apical shoot removal produced a cumulative 25.93 ± 0.84 suitable shoots per plant after 12 months, providing a reliable source of propagules. Rooting performance was significantly affected by IBA concentration, rooting substrate, and cutting length. Among the tested treatments, 1.0% IBA was the most effective concentration for root induction. The best rooting performance was obtained in a substrate containing 25% sand and 75% coir dust, with a rooting percentage of 90.00 ± 5.00%, 8.13 ± 0.12 roots per cutting, and a mean root length of 4.83 ± 0.24 cm. Apical cuttings 10–15 cm in length rooted better than 15–20 cm cuttings. For nursery growth, potting media containing 75% soil + 25% coir dust or 50% soil + 50% coir dust gave the best performance, with 100% survival and plant heights of 30.93 ± 0.66 cm and 30.33 ± 0.56 cm, respectively. After 18 months, cutting-derived plants reached 81.43 ± 2.13 cm in height and 1.15 ± 0.05 cm in basal diameter, outperforming seed-derived seedlings. These findings indicate that apical cutting is a promising propagation approach for conservation and restoration of T. wallichiana.

Activity patterns of mammals in commercial plantations of South-central Chile

Sun, 31 May 2026 00:00:00 GMT

Commercial plantations have been recognized worldwide as “green deserts” due to their low biological diversity. This fact is explained by the low availability of resources, which would result in a change in the interactions between species. While changes in occupancy among species in plantations have been documented, little is known about their species’ temporal ecology, as competitors, predators or prey. We studied the activity patterns of the mammals of Pinus radiata plantations. We used photo-trapping to explore their temporal patterns and the overlap among species. Five native and three exotic mammal species were detected, as well as humans. The broader temporal niche breadth was shown by pudu deer (a dwarf deer but still the largest native prey) and the domestic dog. While the temporal overlap was high among similar-sized species, they differed in their use of space. Among prey, birds were the most abundant, and their activity patterns were essentially diurnal. Ecological aspects of the species are discussed, both in relation to the temporal flexibility of the species and the structural complexity of the study area.

Changes in soil physical properties and understory vegetation in abandoned skidding trails

Sun, 31 May 2026 00:00:00 GMT

Skidding trails are primary pathways for transporting harvested timber from stumps to landings near forest roads. While they function as temporary routes for logging, their construction can alter ecological dynamics, potentially affecting plant regeneration, diversity, and species composition. This study investigated the physical properties of soil specifically bulk density, soil moisture, saturation, and field capacity as well as the biodiversity of understory vegetation within abandoned skidding trails in the Hazarjarib forest of Iran. Four skidding trails of varying ages (15, 25, 35, and 45 years past-skidding) were selected for the analysis. At each logging route, three plots were established; for each plot, an off-route control plot was placed nearby. To assess the richness and diversity of understory vegetation, we employed various metrics including evenness, Margalef richness index, and the Simpson, Shannon, and Sorenson diversity indices. Results showed that there is significant difference in all investigated soil parameters between the skidding trails and the untrafficked areas (control) except skidding trail with 45 years. The 15-years skidding trail exhibited the highest bulk density (1.80 g cm–3), while the 45-year skidding trail showed the lowest (1.46 g cm–3). This suggests that after 45 years since the last skidding, the bulk density has decreased and is now comparable to that of the untrafficked control area. Also, we observe a higher diversity of species and genera in the control areas compared to the skidding trials.

Biodiversity restoration potential: a comparative study of native species regeneration in natural forests and Liquidambar excelsa plantation forests

Sun, 31 May 2026 00:00:00 GMT

The identification of natural succession and regeneration processes is crucial for the preservation of biodiversity and ecosystem stability in sustainable forest management. This study investigated the biodiversity and regeneration of natural forests and Liquidambar excelsa (Noronha) Oken plantations. Tree species richness (dbh ≥ 10 cm) in natural forests was found to be significantly higher (44 species) than in plantation forests (5 species, 4 of which were natural recruits). Although tree density was higher in natural forests, basal area was lower than in plantations. At the regeneration (sapling) level, species richness did not differ significantly between the two forest types, with a moderate diversity index and high evenness, and a species similarity of 60.7%. However, sapling density and basal area were higher in the plantation forests. For understory vegetation, species richness was also not significantly different, but the diversity index was higher in the natural forests. Both shared a very high species similarity (75.6%), despite the greater density and cover in the natural forests. The successful recruitment of native species into plantations is more influenced by environmental factors such as proximity to natural forest seed sources and topography, rather than by the forest type itself. This is demonstrated by the discovery of L. excelsa seedlings in natural forests and the presence of several native species that have successfully regenerated in plantation forests, indicating the potential for biodiversity restoration.

Effect of culture media on radial growth and fructification of ophiostomatoid fungi isolated from bark beetles

Mon, 26 Jan 2026 00:00:00 GMT

Ophiostomatoid fungi are important associates of bark beetles (Scolytinae) and cause sapstain and tracheomycosis in trees. We examined the growth and fructification of seven species from the genera Ophiostoma, Graphilbum, Leptographium, and Grosmannia, isolated from bark beetle species of the genera Ips, Orthotomicus, and Pityogenes collected from Scots pine (Pinus sylvestris). Ten isolates were cultivated on water agar (WA), malt extract agar (MEA), MEA with tyrosol (T), and MEA with vitamins (biotin, thiamine, pyridoxine) to determine the optimal medium for growth and fructification. Radial growth varied significantly among media and isolates. The fastest radial growth was observed on MEA supplemented with tyrosol at 0.5 µL per 250 mL (T0.5). Fructification of Ophiostoma minus and Leptographium piceaperdum was significantly higher on the nutrient-poor WA, MEA with tyrosol, and vitamin-enriched MEA than on plain MEA. The results highlight the importance of medium composition for fungal fructification and provide a basis for optimizing fungal development under different conditions.

Influence of forest stand on the reproductive biology of the edible dormouse Glis glis

Mon, 26 Jan 2026 00:00:00 GMT

In this study, carried out between 2018 and 2024, we investigated how stand species composition, stand age, and tree mast cycles affect selected life functions of the edible dormouse. A total of 81 nesting boxes were installed in eight study plots in south-western Poland in an area of low hills covered by deciduous and mixed forests. The locations varied in tree species composition and stand age. The number of inspections conducted annually ranged from 1 to 7. A total of 208 dormice (including 128 juveniles from 28 litters) were recorded. There was no association between the average number of litters per year and stand age, but there was a clear difference in this trait between oak and beech forests (in favour of the former). The number of litters increased in mast years, while the total number of dormice observed in mast and non-mast years did not differ significantly. Juveniles outnumbered adults in seeded years, but the difference was not significant. The study showed that nest boxes were more readily occupied in younger stands. More nest boxes were occupied in oak forests than in beech forests.

Non-native Monk Parakeets (Myiopsitta monachus) in Rome’s largest urban parks: nest density, host tree characteristics, and management recommendations

Mon, 26 Jan 2026 00:00:00 GMT

Non-native Monk Parakeets (Myiopsitta monachus) are invasive birds widely distributed in European urban parks. Studying the nesting sites of urban populations is mandatory since these areas often serve as initiation of colonization processes in surrounding non-urban environments, posing a risk to agricultural crops and commercially valuable orchards. Therefore, understanding the density and distribution of nesting sites, as well as the structural characteristics of both the nests and their host trees, becomes crucial. In this study, we surveyed all Monk Parakeet nests in the five largest urban parks in Rome. Our data provides new insights for urban habitats supporting previous findings on nest-tree selection in Monk Parakeets. We recorded 66 nests on 30 trees belonging to four ornamental species: Cedrus libani, Phoenix canariensis (or P. dactylifera), Pinus pinea, and Trachycarpus fortunei. Cedars and palms were the most frequently used host trees, with nest density varying among parks (2 nests per 10 hectares, approximately). Nests were typically located at heights of around 13–14 meters, and parakeets showed a preference for taller trees with larger trunk diameters. These larger trees offer increased stability (e.g., during adverse weather) and, for highly social species like this, allow to build nests in higher (and then sure) positions, in terms of group dynamics and predator avoidance. Differences in tree architecture may account for the variation in relative nest height (nest height/tree height ratio, %) among species: in palms, nests are placed higher in the canopy (87.76% ± 7.03) compared to those in cedars (64.7% ± 16.4). Cedars hosted a significantly greater number of nests per tree (2.8 nests/tree ± 1.82; n = 20 nest trees) compared to palms. Our findings, combined with citizen-science data, could contribute to more effective management and control strategies—not only within urban parks but also at finer spatial scales, such as private gardens and residential areas.