Search Results (565)

Mediterranean dehesas are open agroforestry systems in which tree configuration and climatic regime condition the organisation of biodiversity. In these landscapes, ants are commonly used as ecological indicators, although the relative importance of local versus regional factors in structuring their communities remains poorly defined. Ant assemblages were sampled using pitfall traps at 15 farms in southern Spain, and the influence of environmental variables defined at two spatial scales was analysed: microhabitat, distinguishing between areas under tree canopy and open areas, and farm as a unit representative of the regional context. The multivariate analyses applied (dbRDA, PERMANOVA and variance partitioning) reveal a hierarchical organisation of community assemblages. At the local scale, community variation was primarily explained by structural attributes of the tree layer, particularly canopy cover and distance to trees. At the farm scale, environmental predictors explained a modest proportion of community variation, with strong overlap among climatic, vegetation and structural variables. Overall, the structure of ant communities in dehesas follows a scale-dependent pattern, in which climate sets the regional framework and tree structure modulates assemblage organisation at a fine scale. Full article

Ash dieback, caused by the fungus Hymenoscyphus fraxineus, continues to threaten European ash (Fraxinus excelsior), yet the contribution of the leaf microbiome to disease severity remains poorly understood. We surveyed 133 ash trees across nine sites in Northern Ireland, using canopy cover as a proxy for health, and characterised leaf-associated microbial communities using Pacific Biosciences (PacBio) long-read amplicon sequencing (full-length 16S and ITS) and QIIME2-based workflows. Many trees exhibited partial tolerance to ash dieback, with most maintaining stable canopy cover year-on-year, while fewer trees show a decline and a smaller portion showing improvement. Microbial communities were largely stable irrespective of ash health with little difference in alpha diversity (Shannon) or beta diversity (Bray–Curtis PERMANOVA) for either bacteria or fungi. Differential abundance and correlation analyses showed that H. fraxineus was, as expected, negatively associated with canopy cover. Only one fungal species, Papiliotrema flavescens, demonstrated a strong positive association with healthier trees, consistent with previous findings. These results indicate that Northern Ireland hosts a reservoir of ash trees displaying tolerance to ash dieback. While the leaf microbiome does not appear to drive this tolerance at the community level, one fungus, P. flavescens, was correlated with healthier ash. Full article

Evapotranspiration and crop coefficients are key variables for designing efficient irrigation strategies in tree crops, yet standard tabulated coefficients derived for mature, fully covering orchards often fail to represent the water use of young, high-density hazelnut systems. In recent years, updated crop coefficients for temperate fruit trees, including hazelnut, and transpiration-based models have been proposed, while several studies have successfully linked Vegetation Indices and thermal metrics to single and basal crop coefficients in vineyards, orchards and field crops. However, no information is available on the use of UAV-derived spectral and thermal indices to estimate crop coefficients in high-density hazelnut orchards. This study compares crop coefficients obtained from traditional approaches (the FAO56 single crop coefficient, a transpiration-based coefficient, and ground cover reduction factors) with coefficients estimated from UAV-derived Normalized Difference Water Index (NDWI) and Crop Water Stress Index (CWSI) in a subsurface-drip-irrigated hazelnut orchard (cv. Tonda Francescana^®) with two planting densities (625 and 1250 trees ha⁻¹) in central Italy. Multispectral and thermal UAV surveys carried out between 2021 and 2024 were used to derive canopy geometrical traits, ground cover, NDWI, and CWSI, while a local weather station provided reference evapotranspiration. Empirical relationships were calibrated between crop coefficients and ground cover, NDWI, and CWSI, and mid-season coefficients were applied to estimate daily crop evapotranspiration, which was then compared with the irrigation volumes supplied during the 2024 season. The standard FAO56 crop coefficient (Kc = 0.9) overestimated evapotranspiration, especially at the lower planting density, whereas ground cover-based reduction factors recalibrated for hazelnut and the transpiration-based coefficient provided estimates more consistent with the applied irrigation. UAV-based NDWI- and CWSI-derived crop coefficients produced mid-season values close to those obtained with the transpiration-based method for both planting densities, confirming that spectral and thermal information can effectively capture the combined effects of canopy development and water status. These results indicate that combining traditional methods with UAV-derived indices offers a flexible framework to refine crop coefficients in high-density hazelnut orchards and support more accurate and spatially explicit irrigation scheduling. Full article

Forest canopy cover is a crucial indicator for measuring ecological functions. However, traditional plot-based measurement methods suffer from low efficiency and insufficient spatial continuity. Addressing issues in UAV RGB imagery—such as tree crown boundary adhesion, shadow interference, and texture confusion—this paper proposes a lightweight and edge-sensitive tree crown segmentation network. The model employs MobileNetV3-Large to replace the traditional U-Net encoder, significantly reducing parameter count and computational load while satisfying the potential for edge device deployment. In the decoding phase, a Semantic-guided Channel Compression and Focus (SCCF) module is designed to enhance semantic-guided channel compression and feature focusing. Furthermore, a Gradient-guided Morphological Tree Crown Attention Module (G-MTCAM) is proposed. By utilizing Gradient-Induced Center Difference Convolution (GI-CDC) and a variance-based statistical gating mechanism, this module constructs a dual-stream architecture for morphology and texture interaction, achieving precise cutting of tree crown boundaries and effective filtering of background noise. Additionally, a boundary-enhanced composite loss function is introduced to improve the accuracy of crown edge identification. Experimental results indicate that the proposed model achieves an IoU, Acc, and F1 score of 88.59%, 88.62%, and 93.77%, respectively. Compared to the classic U-Net, these represent improvements of 2.77%, 1.71%, and 1.44%, while the parameter count and computational cost are only 5.98 M and 6.71 GFLOPs. The forest Canopy Cover (CC) estimated based on the segmentation results shows high consistency with ground-based near-zenith canopy hemispherical percentage ($CH{P}_{0–30}$, denoted as $C{C}_{obs}$), with a correlation coefficient ($R^2$) exceeding 0.90. This verifies the effectiveness of the method in forest canopy structure monitoring and provides technical support for the application of consumer-grade UAVs in forestry surveys. Full article

Drought-induced tree mortality is a growing threat to Mediterranean ecosystems, which host high biodiversity but face increasing water stress under climate change. Detecting mortality over large areas with satellite data remains challenging due to open canopies and mixed pixels that obscure vegetation signals. This study evaluates the performance of two widely used vegetation indices—the Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI)—alongside a novel application of Spectral Unmixing derived vegetation cover Spectral Unmixing (SU) within the LandTrendr algorithm to track tree mortality in southwest Crete, Greece. High-resolution Unmanned Aerial System (UAS) imagery was used to validate satellite observations, demonstrating strong agreement with field data ($R^2$ = 0.95) and confirming its suitability as reference data. LandTrendr applied to NDVI, NDWI, and SU detected major mortality events between 1995 and 2008, with SU identifying the largest affected area. While NDVI and NDWI achieved higher accuracy in distinguishing unaffected plots, SU performed best at detecting mortality. Regression analysis revealed a limited ability of all approaches to quantify mortality magnitude, though SU improved when high-mortality plots were excluded. Overall, NDVI effectively tracked canopy changes, NDWI provided early warnings of drought stress, and SU reduced soil interference to better capture mortality patterns. By integrating satellite time series with UAS validation, this study demonstrates a scalable approach for detecting forest decline and offers actionable insights to guide Mediterranean forest management under increasing drought pressure. Full article

Past restoration of hardwood forests prioritized planting of woody vegetation cover, particularly oaks (Quercus spp.). This restoration regime often did not consider other microhabitat components, which failed to restore habitat complexity. Giant cane (Arundinaria gigantea (Walter) Muhl.) was an important microhabitat feature for creating a dense understory structure within the hardwood forest landscape. Many bird species are associated with stands of giant cane (canebrakes) for food, cover, and nesting ground. The decline of canebrakes may reduce nesting and foraging habitat, negatively impacting bird communities. Here, we used a hierarchical multi-species occupancy model to assess how giant cane and its associated overstory forest structure influenced breeding bird occupancy in southern Illinois. Bird surveys were conducted from May to July 2022–2024 at 100 site-years using passive acoustic monitoring. Responses to the vegetation structure (tree density and size) and canebrakes varied among species and nesting guilds (overstory, understory, and ground). Occurrence probabilities of 54% of the bird species increased with the presence of canebrake. We did not find any significant relationships between bird occupancy and vegetation structure and canebrake characteristics. Overall, maintaining a hardwood forest stand with a heterogeneous canopy cover would create variations in light environments, allowing canebrakes to benefit bird species across nesting guilds. Full article

Martagon Lily, Lilium martagon, belongs to geophytes inhabiting mainly forest communities in temperate regions of Europe and Asia and it is considered as a rare and endangered species in many regions. The presented investigations were conducted in three populations, occurring in forest habitats in Southern Poland: Wolski Forest (population 1), Mount Chełm (population 2), and Hrabeński Forest (population 3). At each site, 10 phytosociological relevés covering an area of 100 m² were taken. For each phytosociological relevé, the Shannon–Wiener, Pielou, and Simpson indices, as well as the number of species, were calculated. The detailed field studies were conducted in permanent study patches measuring 20 m × 20 m. The measurements of habitat conditions (e.g., number of species, soil moisture, light intensity at ground level, height of plant cover) were carried out in 2018. The observations of the abundance and developmental structure of stems, as well as selected traits (e.g., height, number and dimensions of leaves, number of flowers) were conducted in 2018–2023. The analysis of phytosociological relevés showed that the study sites in Wolski Forest and Mount Chełm were located in the Tilio cordatae–Carpinetum betuli oak-hornbeam forest association, while the study site in Hrabeński Forest was situated in the Dentario glandulosae–Fagetum mountain beech forest association. The statistical analysis confirmed that the greatest Shannon and Simpson index values, number of species, soil humidity, light intensity at ground level, and height of plant cover were recorded in Hrabeński forest. The greatest number of Lilium martagon stems and a lack of juvenile stems was found in population 3, while in less abundant populations—1 and 2—juvenile, immature, virginile, and generative stems were found. The statistical analysis showed that the highest immature and virginile stems with the greatest number of whorl leaves, as well as the substantial height of generative stems and number of whorl leaves observed in population 3, might be the result of growing in conditions of lateral shading provided by adjacent plants. The lowest height of immature and virginile stems recorded in population 1 and generative stems noticed in population 2 might be caused by them being overshaded by the canopy of surrounding trees. Moreover, the obtained results suggest the favourable impact of weather conditions during the meteorological spring and summer of 2019 on the growth of Lilium martagon stems. Nevertheless, the lack of a unified trend in the studied populations indicates the occurrence of site-specific temporal variability of individual traits. Considering the obtained results, it can be concluded that population 3 presents a much better state and prospects for persistence in the occupied site than populations 1 and 2. At the same time, it should be pointed out that further long-term observations of populations of Lilium martagon located in different habitat conditions are still strongly desired. Full article

The global push to advance smart and digital forestry relies on emerging technologies to support efficient, AI-assisted, and data-driven forest management, but many forest operations occur in remote forests where reliable internet connectivity is unavailable. Low Earth Orbit (LEO) satellite constellations such as Starlink may provide reliable connectivity where cellular networks are unavailable. The performance of LEO-based solutions remains poorly understood under forest canopies, and empirical evaluations linking canopy characteristics to connectivity performance are largely lacking. In this study, the effect of forest vegetation on Starlink performance below the canopy was evaluated by placing a satellite receiver at thirty randomly selected permanent single tree inventory plots on the University of Idaho Experimental Forest and measuring connection success, connection time, and upload and download speeds along 50 m transects in all cardinal directions. LiDAR-derived stand density index (SDI), leaf area index (LAI), rumple index (RI), and vegetation cover (VC) were used to quantify canopy structure. Principal Component Analysis and survival analysis showed that higher values of PC1, primarily driven by SDI, LAI, and RI, reduced the probability of establishing a connection. Linear regression analysis indicated that higher SDI increased connection time, indicating that denser stands slowed or prevented connectivity. Linear mixed-effects models demonstrated that internet speed primarily declined with increasing distance, with download and upload rates dropping beyond 40 m from the router. LAI, RI, and VC did not influence connection time or speed, suggesting that overall stand density rather than leaf area per unit ground area has a greater impact on signal obstruction. Overall, dense forest structure and distance are the main constraints on LEO satellite connectivity and performance, and understanding these limitations supports the development and deployment of satellite-based networking to advance smart forestry operations. These results provide one of the first quantitative assessments of LEO satellite connectivity constraints in operational forest conditions, offering practical guidance for deploying satellite-based networks to support smart forestry applications in remote environments. Full article

Historic linear corridors in living-heritage settings concentrate identity, everyday mobility, and visitor experience. Balancing authenticity, adaptability, and publicness therefore benefits from evidence that jointly characterizes long-term physical change, network accessibility, and eye-level interface conditions. Existing assessments often focus on façades or single time slices, leaving limited evidence that relates decades of built-fabric reconfiguration (changes in building footprints, street edges, and open-space fragmentation) to multi-scale accessibility and pedestrian-facing qualities. We propose an integrated and interpretable workflow for the Beishan Street corridor in the West Lake World Heritage core (Hangzhou) over 1929–2024. Scale-sensitive morphological metrics, multi-radius network measures (integration and centrality), and street-view semantic segmentation are aligned at corridor-segment resolution and examined together with segment-level functional intensity derived from POIs using transparent linear models. The results indicate a long-term shift from a lakeshore-led to a road-led spatial logic, followed by post-2000 stabilization near saturation. Average integration increases, while the high-integration tail becomes thinner. In connector-removal scenarios, the eastern segment shows a relative accessibility decline, and a central hinge node emerges as a vulnerability hotspot (bottleneck) where through-movement concentrates. Eye-level profiles differ by segment: the west exhibits maximal canopy and lower sky visibility, the center shows stronger continuous walls around compounds with intermittent forecourt openings, and the east is characterized by compact residential heritage frontage with low vegetation. Segment-level associations suggest that address and wayfinding density tends to co-occur with clearer frontages, wider sky cones, and stronger tree cover. Transportation-related and access/passage facilities tend to co-occur with higher ground-plane legibility, measured as wider and more continuous road and sidewalk surfaces. Medical and government clusters tend to co-occur with lower sky openness. Recommended actions include the following: (1) mesh-aware protection of key connectors and the hinge, (2) segment-specific targets for façade share and ground cues with planned punctuations, (3) tailored interface standards for institutional clusters, (4) scalable address and wayfinding systems, and (5) event staging that preserves effective roadway and sidewalk capacity. Full article

Urban green spaces (UGSs) are crucial for public health by supporting leisure-time physical activities (LTPAs), but the mechanisms by which micro-scale UGS features shape different LTPA types remain unclear. In this study, the relationship between the micro-scale features of UGSs and LTPAs was investigated in 63 sample plots of nine comprehensive parks in downtown Shanghai. Using the behavior annotation method and multiple linear regression analysis, we identified significant correlations between the UGS features and LTPA types. The results showed that sitting and chatting (SC) activities had the highest participation rate at 46.84%, while sports and fitness (SF) activities had the lowest at 9.82%. Walking and sightseeing (WS) activities and culture and entertainment (CE) activities accounted for 19.99% and 23.35% of participants, respectively. Spatial accessibility (SA) and canopy coverage ratios (CCRs) were significantly negatively correlated with SC, while seat number (SN), ground-cover density (D_GNC), and three-dimensional green quantity (TGQ) were positively correlated. For WS, SN and tree density (D_TREE) were positively correlated, while TGQ was negatively correlated. CE activities were positively associated with SN, D_TREE, and Shannon’s diversity index of ground-cover (SHI_GNC) but negatively associated with Shannon’s diversity index of trees (SHI_TREE). The regression models explained 65.9%, 38.3%, and 44.3% of the variance in SC, WS, and CE, respectively, while the overall model was not significant for SF. These findings highlight the need to optimize rest facilities, vegetation diversity, and spatial layout in UGS design to accommodate diverse LTPA needs and foster health-oriented environments. The conclusions are mainly applicable to seasons with mild climates, and LTPA characteristics in different seasons require further verification. Full article

Illegal logging is a major driver of tropical deforestation, accounting for the majority of timber harvested in many tropical countries and degrading many protected areas, due to both weak law enforcement capacity and corruption. Commercial logging is illegal in Peru’s Allpahuayo-Mishana National Reserve, a state protected area, but clandestine logging operations persist and affect its biodiversity, including the endemic bird species associated with its rare Amazonian white-sand forests. We examined the effects of illegal logging operations on white-sand forest understory bird communities as sentinels of biodiversity. We sampled birds with mist nets at 12 study sites in unlogged forest and forest regenerating between 1 and 10 years after timber harvest, capturing and releasing 348 birds representing 54 species in 16 families. Forest structure differed significantly between forest treatments, with canopy cover in logged forest significantly lower than in unlogged forest. All avian foraging guilds tested (including ant followers, other insectivores, frugivores, granivores, and nectarivores) responded significantly to changes in one or more forest structure characteristics we measured. The abundance of ant followers and other insectivores was positively correlated with canopy cover, while granivore abundance was positively correlated with subcanopy cover, and both frugivore and nectarivore abundance was negatively correlated with the numbers of trees in white-forest stands. We also took a rare opportunity to compare avian foraging guilds and relative abundance using capture data collected at the same white-sand forest sites in both 2005 and 2023. Over this 18-year period, the total number of understory birds and ant followers in particular declined, whereas other insectivores increased with time since logging. Our results demonstrate that logging has significant influences on white-sand forest habitat structure and bird community dynamics for decades after logging events. Illegal logging threatens forests and wildlife in many tropical protected areas, and we recommend their managers prioritize both preventing illegal logging and mitigating its negative effects to effectively conserve biodiversity. Full article

Wildfires pose increasing challenges for Mediterranean landscapes, making rapid and reliable mapping of burn severity essential for management and recovery planning. This study applies an integrated geospatial workflow to wildfires that occurred in Greece during the 2024 summer season. Sentinel-2-derived dNBR and RBR indices were used to map burn severity, while CORINE Land Cover and Tree Cover Density datasets provided complementary context for interpreting how severity varied across different vegetation types and canopy-density conditions. A one-way ANOVA was used to summarize differences in burned area among severity classes. The results show that low and moderate-low severity levels dominated most fire perimeters, whereas high-severity patches were spatially limited and typically coincided with densely forested areas. Validation against Copernicus Emergency Management Service data yielded an overall agreement of approximately 94%, indicating that the applied multispectral workflow produced severity extents broadly consistent with independent operational products. By applying a consistent methodology across multiple fire events, this study demonstrates the value of combining spectral indices with land-cover information for interpreting severity patterns and supporting post-fire management. The findings highlight the usefulness of freely accessible remote sensing data for timely fire assessment in Mediterranean environments and provide a basis for future multi-regional and multi-year comparisons. Full article

The eastern Baltic region is rich in hemiboreal forests, which are both commercially important and provide habitats for rare and/or endangered forest-dwelling species, which are sensitive to accelerating climatic changes. Under the intensifying climatic disturbances that are stressing forests worldwide, sanitary logging is a widely used harvesting technique for the mitigation of commercial losses. The effects of salvage logging on the biodiversity of forests remain ambiguous due to the larger scale and higher intensity of timber harvesting, which can alter the recovery of stands and succession of their vegetation. Furthermore, EU legislation is increasingly emphasizing conservation/restoration and mandating its implementation. The recovery of ecosystems, and hence the biodiversity of disturbed managed forests, can take several decades to centuries, depending on the site conditions. Long-term (~60 years, four remeasurements) changes in the composition and structure of vegetation, as an indicator of overall health and nutrient cycling, were studied in conventionally managed hemiboreal forests. Potential forest transformation (paludification) risks associated with large-scale logging were assessed in mixed coniferous stands in the Baltics, Latvia. Following logging, the stands were conventionally managed, including artificial regeneration. According to ground cover vegetation, 50 years was the period for the disturbance effects to start subsiding, as a dynamic equilibrium was reached and the canopies of regenerating trees were closing. A gradual decrease in moisture levels in the middle parts of salvage-logged areas, and later at their edges, indicated that the stands have escaped paludification, likely as the climate has been warming. Distance from the edge of the salvage-logged areas had a secondary effect on ground cover vegetation recovery after storms, alleviating concerns about the explicit negative impact of the scale of harvesting. Thus, in managed seminatural forest landscapes with a historically small to moderate scale of anthropogenic disturbance, salvage logging at a scale locally deemed as large had a transient effect in the Baltics. This indicates successful regeneration of the forest ecosystem over a timeframe shorter than the conventional rotation period, suggesting overall conservation efficiency of conventionally managed forests. Accordingly, salvage logging can be sustainable in terms of biodiversity and forest continuity in the long run under traditional management, as environmental changes accelerate. Full article

Progressive climate change, intensified urbanization, and deteriorating urban environmental quality pose significant challenges for compact mid-sized city centers, where limited land availability and strong investment pressure hinder the development of green spaces. In this context, green and blue infrastructure (GBI) is increasingly seen as a key element of climate change adaptation strategies and strengthening the resilience of cities. This study aims to assess the state of GBI in the city center of Rzeszów and identify the opportunities for its integration into a coherent and multifunctional public space system. The research was conducted using a case study method combining GIS spatial analyses, remote sensing data (NDVI index), an assessment of the accessibility of green spaces according to the 3–30–300 rule, an expert assessment of the quality of public spaces, and field visits to the selected areas. An analysis of changes in vegetation cover between 2016 and 2024 showed a systematic decline in the proportion of green areas and insufficient tree cover and continuity in the GBI system. The results indicate that, despite the relatively good accessibility of larger green areas within a 300 m radius, the city center does not meet the key criteria for tree visibility, tree canopy coverage, and the creation of a coherent GBI system. The areas with the greatest integration potential were identified as the Wisłok River valley, marginal spaces, interiors between blocks, and green microforms, such as pocket parks, rain gardens, and linear greenery. The results obtained form the basis for formulating planning recommendations to support the development of GBI in densely built-up city centers. Full article

In the context of global climate change and rapid urbanization, integrating urban blue-green infrastructure into the built environment is essential for mitigating the urban heat island effect and enhancing climate resilience. Focusing on urban riparian corridors as vital natural cooling systems, this study aims to: (1) quantify their cooling performance in terms of intensity and distance; (2) identify the key landscape drivers and their relative importance; (3) uncover nonlinear relationships and determine ecological thresholds for optimal thermal regulation; and (4) translate these findings into science-based guidelines for climate-adaptive design and sustainable management. Taking 27 representative riparian green spaces in Zhengzhou, China (average area: 17,539 m², range: 10,027–42,690 m²) as a case study, nine key factors characterizing vegetation structure and composition, corridor morphology, and blue-green spatial pattern were used as predictors in a Boosted Regression Tree (BRT) model to analyze their contributions and marginal-effect thresholds. Results show that these corridors provide substantial cooling, with an average intensity of 5.43 °C extending over 215.56 m. Canopy Density, 3D Green Volume per Unit Area, and Green Cover Ratio emerged as the three core drivers, jointly explaining >86% of the cooling performance. The key innovation lies in identifying explicit, design-oriented ecological thresholds—for example, cooling efficacy stabilizes when Green Cover Ratio reaches ~77%, Canopy Density attains 0.7, and the Blue-Green Space Width Ratio approaches 1:1. These thresholds can be directly translated into performance benchmarks for sustainable urban planning and landscape engineering, providing evidence-based parameters for optimizing vegetation structure and spatial configuration. This study demonstrates that applying quantified ecological thresholds can transform riparian corridors into efficient climate-resilient infrastructure, thereby synergistically improving thermal comfort, enhancing ecosystem services, and promoting sustainable land use in urban environments. Full article