Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Search Results (1,428)

Search Parameters:
Keywords = Shannon diversity index

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
17 pages, 931 KB  
Article
Integrated 16S rRNA Sequencing and Metabolomics Reveals Niche-Specific Microbiome and Metabolome Changes Associated with Toxoptera aurantii Infestation
by Yunchao Wang, Peipei Long, Nian Wen, Manting Zhang, Jingjing Li, Xiong Yan, Zhongjiu Xiao and Kun Yang
Microorganisms 2026, 14(7), 1463; https://doi.org/10.3390/microorganisms14071463 - 3 Jul 2026
Viewed by 15
Abstract
Toxoptera aurantii is a globally distributed piercing-sucking pest that severely threatens tea production. While the direct damage caused by aphid feeding is well documented, the systemic effects of infestation on plant-associated and soil microbial communities remain poorly understood. Here, we employed full-length 16S [...] Read more.
Toxoptera aurantii is a globally distributed piercing-sucking pest that severely threatens tea production. While the direct damage caused by aphid feeding is well documented, the systemic effects of infestation on plant-associated and soil microbial communities remain poorly understood. Here, we employed full-length 16S rRNA gene sequencing and untargeted metabolomics to investigate the influence of T. aurantii infestation on the microbiota of tea plants (Camellia sinensis) and rhizosphere soil across four sample compartments: aphid bodies, healthy leaves, aphid-infested leaves, and root-zone soil. Our results revealed pronounced niche-specific microbial assembly patterns. The aphid microbiome exhibited the lowest diversity and was dominated by obligate endosymbionts, including Buchnera aphidicola and the secondary symbiont Serratia symbiotica. Soil harbored the highest microbial diversity with a balanced phylum-level structure. Aphid infestation significantly reduced phyllosphere microbial diversity (Shannon index) and shifted community composition, with a decline in a sequence putatively assigned to Methylobacterium brachiatum and a modest increase in a taxon assigned to the opportunistic plant pathogen OTU assigned to Dickeya chrysanthemi. This pattern suggests a hypothesis that aphid infestation may create conditions permissive for such opportunistic pathogens, although experimental validation is required. Concurrently, infestation was associated with profound metabolic reprograming in tea leaves, including upregulation of defense-related flavonoids and terpenoids and downregulation of several primary metabolites. Notably, the phyllosphere of infested leaves showed reduced microbial diversity and an increased relative abundance of a 16S rRNA sequence assigned to Dickeya chrysanthemi, while certain plant-derived antimicrobial metabolites were decreased. These patterns suggest a possible association between aphid infestation, altered antimicrobial metabolite profiles and increased relative abundance of Dickeya-assigned sequences. These findings demonstrate that T. aurantii infestation triggers a systemic response in the aboveground compartments (aphid and leaf), while the soil compartment maintains a distinct and highly diverse microbial community that serves as a potential reservoir. The study characterizes microbial communities across these three compartments without inferring infestation-driven soil remodeling. This study advances our understanding of tripartite interactions in tea ecosystems and provides a basis for developing microbiome-based strategies for sustainable pest management. Full article
(This article belongs to the Special Issue Insect–Microbe Symbiosis)
Show Figures

Figure 1

18 pages, 1193 KB  
Article
Effects of Different Soybean Protein Sources on Growth Performance, Feed Utilization Efficiency, and Gut Microbiota of Pacific White Shrimp (Litopenaeus vannamei) in Green Water and Clear Water Systems
by Aakriti Khanal, Khanh Q. Nguyen, Cristhian S. Andres, Adela N. Araujo, Trenton L. Corby, Melanie Rhodes, Timothy J. Bruce and D. Allen Davis
Aquac. J. 2026, 6(3), 25; https://doi.org/10.3390/aquacj6030025 - 2 Jul 2026
Viewed by 74
Abstract
Two growth trials were conducted to evaluate the effects of solvent-extracted soybean meal (SBM), low-oligosaccharide soybean meal (LO-SBM), and enzyme-treated soybean meal (ET-SBM) on the growth performance, feed utilization, and gut microbiome of the Pacific white shrimp (Litopenaeus vannamei). Nine diets [...] Read more.
Two growth trials were conducted to evaluate the effects of solvent-extracted soybean meal (SBM), low-oligosaccharide soybean meal (LO-SBM), and enzyme-treated soybean meal (ET-SBM) on the growth performance, feed utilization, and gut microbiome of the Pacific white shrimp (Litopenaeus vannamei). Nine diets were tested, including a basal diet using solvent-extracted soybean meal as the main protein source. The solvent-extracted soybean meal was then replaced with LO-SBM or ET-SBM at 40%, 60%, 80%, and 100% on an isonitrogenous and isolipidic basis. In the 8-week outdoor green water trial, all growth metrics, FCR and apparent net protein retention (ANPR) showed no significant differences among diets (p > 0.05). However, there was a significant effect of LO-SBM on phosphorus retention. In the clear water trial, intermediate inclusion levels of LO-SBM (60–80%) slightly improved growth metrics and phosphorus retention (p < 0.05) without affecting protein utilization, while 100% LO-SBM did not provide additional benefits. Diets with ET-SBM showed similar performance; however, phosphorus retention was reduced. Diets did not affect whole-body composition (p > 0.05), except for phosphorus and moisture. Gut microbiota analysis revealed that shrimp fed 100% ET-SBM had notably higher alpha diversity (Shannon index = 5.45, observed species = 326.41) compared to those fed 100% LO-SBM (Shannon index = 4.59, observed species = 242.69), indicating improved microbial stability with ET-SBM. Nonetheless, there were no significant differences in beta diversity or taxonomic composition between treatments (p > 0.05). This study demonstrates that incorporating 60–80% LO-SBM into the diet improves shrimp growth and nutrient utilization. Additionally, ET-SBM may also support shrimp growth, nutrient efficiency, and microbial diversity, suggesting that both LO-SBM and ET-SBM can be beneficial for shrimp nutrition. Full article
Show Figures

Figure 1

20 pages, 3209 KB  
Article
Scale Effects on Plant Diversity in the Gurbantunggut Desert
by Yushan Dong, Gulmira Nurmaimaiti, Yong Zeng, Yuntong Liu, Peng Wang and Yuejia Liang
Diversity 2026, 18(7), 396; https://doi.org/10.3390/d18070396 - 29 Jun 2026
Viewed by 188
Abstract
Revealing scale effects and the mechanisms underlying the relationships between plant species and functional diversity is crucial for understanding the stability of desert ecosystems and formulating multiscale conservation strategies. In this study, the spatial patterns of plant species and functional diversity in the [...] Read more.
Revealing scale effects and the mechanisms underlying the relationships between plant species and functional diversity is crucial for understanding the stability of desert ecosystems and formulating multiscale conservation strategies. In this study, the spatial patterns of plant species and functional diversity in the Gurbantunggut Desert were analysed via multiscale grid sampling. The results indicated that (1) both species diversity and functional diversity indices exhibited high spatial heterogeneity. At the small scale (10 m × 10 m), the values of the Shannon–Wiener and Pielou indices for fixed dunes were higher in the south than in the north. At the medium and large scales (20 m × 20 m and 50 m × 50 m, respectively), the index values were highest in the southwest, with generally greater values in the south than in the north. For semifixed and mobile dunes, the Shannon–Wiener and Pielou index values exhibited an east-high–west-low pattern at the 10 m × 10 m scale. This differentiation decreased with increasing scale, with the highest values observed in the northeast and southwest at the 50 m × 50 m scale. The spatial differentiation in functional diversity indices (Rao’s second-order entropy index and functional evenness index) exhibited distinct characteristics across the different dune types. (2) The spatial variation in all the diversity indices monotonically decreased with increasing scale, with the variance in the species diversity indices indicating the following order: Shannon–Wiener index > Pielou index > Simpson index. (3) The relationships between species richness and diversity indices exhibited significant scale dependence. At the small and medium scales, species richness was significantly positively correlated with the Shannon–Wiener index, Simpson index, and Rao’s quadratic entropy index and significantly negatively correlated with the Pielou evenness index and functional evenness index. However, at the large scale, none of these correlations were significant. (4) The species diversity indices and Rao’s quadratic entropy index were significantly positively correlated at the small and medium scales (p < 0.01), whereas a significant positive correlation with the functional evenness index was observed only at the 10 m × 10 m scale (p < 0.01). At the larger scale, these correlations became insignificant. In fixed dunes, areas of high Simpson index values exhibited a spatially complementary distribution with areas of high Shannon–Wiener index and Pielou index values, providing evidence for the combined effect of local processes such as competitive exclusion and dispersal limitation. Through comprehensive multiscale analysis, this study revealed the mechanisms underlying the scale-dependent relationships between plant species and functional diversity, thereby providing a theoretical basis for protecting and restoring desert biodiversity. Full article
(This article belongs to the Section Plant Diversity)
Show Figures

Figure 1

29 pages, 4998 KB  
Article
Phenotypic Variation in Water-Use Efficiency, Heat Tolerance, and Carbon Isotope Discrimination Across Canadian Spring Wheat Cultivars Under Climate Stress
by Ludovic Joseph Anatole Capo-chichi, Scott X. Chang, Pierre Hucl, Mazen Aljarrah, Jennifer Zantinge, Michael Holtz, Ammar Elakhdar, Muhammad Iqbal and Guillermo Hernandez-Ramirez
Plants 2026, 15(13), 1958; https://doi.org/10.3390/plants15131958 - 25 Jun 2026
Viewed by 254
Abstract
Understanding phenotypic variation in traits associated with drought and heat tolerance is essential for developing climate-resilient spring wheat cultivars under increasingly variable environmental conditions. To evaluate phenotypic and physiological variation in water-use efficiency (WUE), carbon isotope discrimination (δ13C), and heat tolerance, [...] Read more.
Understanding phenotypic variation in traits associated with drought and heat tolerance is essential for developing climate-resilient spring wheat cultivars under increasingly variable environmental conditions. To evaluate phenotypic and physiological variation in water-use efficiency (WUE), carbon isotope discrimination (δ13C), and heat tolerance, 198 Canadian spring wheat cultivars representing diverse breeding backgrounds were assessed under controlled drought and high-temperature conditions. Traits measured included whole-plant water-use efficiency (WUEWP), carbon isotope composition (δ13C), biomass accumulation, water use per plant, and chlorophyll fluorescence across six developmental stages. Whole-plant WUE ranged from 3.07 to 7.81 g L−1, while δ13C values ranged from −24.06‰ to −29.33‰. Biomass accumulation and water use were strongly positively correlated (r = 0.94, p < 0.001), indicating that greater biomass production was associated with increased water consumption. In contrast, the relationship between WUEWP and δ13C was weak (r = −0.09), suggesting that δ13C alone may not be a reliable proxy for WUEWP under combined drought and heat stress conditions. Phenotypic diversity across the cultivar panel was relatively low to moderate (Shannon diversity index, H = 1.88–2.62), indicating limited adaptive capacity within the evaluated germplasm. Principal component analysis explained 76.6% of the total variation and effectively differentiated cultivar responses to stress. Chlorophyll fluorescence, particularly the maximum quantum efficiency of PSII photochemistry (FV/FM), was highly sensitive to stress-induced reductions in photosynthetic performance. Measurements obtained during reproductive drought and heat stress stages showed stronger associations with biomass, water use, WUEWP, and δ13C than measurements collected during non-stress periods, indicating that FV/FM can be a reliable physiological indicator for screening drought and heat tolerance. Overall, the results revealed detectable phenotypic variation but relatively modest diversity and generally weak to moderate trait associations, highlighting the potential value of incorporating diverse germplasm and integrated phenotyping approaches to improve climate resilience in Canadian spring wheat. Full article
(This article belongs to the Special Issue Physiological and Molecular Basis of Plants to Abiotic Stress)
Show Figures

Figure 1

22 pages, 14528 KB  
Article
Fire Heat and Ash Deposition Regulate Post-Fire Soil Bacterial Community Recovery and Predicted Function Potential
by Yu Sun, Zi-Hao Deng, Yao-Quan Yang, Xiao-Chao Pu, Li-Wei Li, Rong She and Xiao-Yan Yang
Fire 2026, 9(6), 262; https://doi.org/10.3390/fire9060262 - 18 Jun 2026
Viewed by 684
Abstract
Disentangling the combined effects of heat and ash in natural forest fires is challenging, hindering understanding of soil microbial post-fire responses. A 90-day simulated fire experiment with 16S rRNA sequencing monitored bacterial communities and functional potential in topsoil (0–10 cm) and subsoil (10–20 [...] Read more.
Disentangling the combined effects of heat and ash in natural forest fires is challenging, hindering understanding of soil microbial post-fire responses. A 90-day simulated fire experiment with 16S rRNA sequencing monitored bacterial communities and functional potential in topsoil (0–10 cm) and subsoil (10–20 cm) under seven treatments: blank control/BC, dry ash/DA, wet ash/WA, low-intensity heating/LH, high-intensity heating/HH, charcoal smoldering combustion/CSC, and Fire, with samples collected every ten days. Results: (1) α diversity declined mainly in the topsoil, with reductions of 12.04–19.82% for Shannon, 1.23–2.86% for Simpson, and 16.03–31.34% for the Chao index. Subsoil only declined under CSC. (2) Both heating and ash treatments increased the relative abundance of low-abundance and endemic taxa. Heating significantly enriched thermotolerant, xerotolerant, and oligotrophic taxa, such as Ramlibacter. (3) Topsoil heating treatments separated from BC (p ≤ 0.01), ash clustered with BC; pH and water content drove differentiation (p ≤ 0.05). (4) Topsoil predicted function potential showed early suppression (0–20 d), mid recovery (30–60 d), and late enhancement (70–90 d) for most treatments, except WA with sustained suppression. Heat determines disturbance depth and initial bacterial loss, while ash reshapes soil properties to influence community reassembly, acting as sequential but distinct environmental filters, providing a framework for post-fire bacterial community reorganization. Full article
Show Figures

Figure 1

15 pages, 1806 KB  
Article
Associations of Diabetes Mellitus Status and Geriatric Nutritional Risk Index with the Gut Microbiota in Nursing-Home Residents
by Teresa Gisinger, Luise Bellach, Christina Fastl, Cátia Pacífico, Marion Nehr, Athanasios Makristathis, Alexandra Kautzky-Willer and Thomas E. Dorner
Nutrients 2026, 18(12), 1966; https://doi.org/10.3390/nu18121966 - 18 Jun 2026
Viewed by 273
Abstract
Background/Objectives: Malnutrition and diabetes mellitus (DM) have been linked to gut microbial perturbations, yet data are scarce for the aging population, especially in a nursing-home setting. As this group is generally at risk for malnutrition, we aimed to investigate the link between DM [...] Read more.
Background/Objectives: Malnutrition and diabetes mellitus (DM) have been linked to gut microbial perturbations, yet data are scarce for the aging population, especially in a nursing-home setting. As this group is generally at risk for malnutrition, we aimed to investigate the link between DM and gut microbial patterns in interaction with nutritional risk status in nursing-home residents. Methods: Stool samples were collected from 173 nursing-home residents (77.5% female, mean age 86 years) and were analyzed via 16S rRNA sequencing. Furthermore, the Geriatric Nutritional Risk Index (GNRI) was assessed and data on comorbidity status, anthropometric measurements, and medication were acquired. Results: Fifty-one residents had DM (mean HbA1c 6%). There were no DM-related differences in alpha diversity (observed richness: p = 0.733; Shannon index: p = 0.747). PERMANOVA revealed slight differences in beta diversity according to GNRI (R2 = 0.009, p = 0.032), but no significant differences when adding DM status. Differential abundance analysis showed Clostridium_Clostridiaceae, Haemophilus, Actinomycetaceae and Micrococcaceae as significantly decreased with DM, independent of age, sex, and BMI. No interaction between DM and the GNRI in microbial diversity or composition was found. Conclusions: We report malnutrition-related differences in beta diversity and diabetes-related microbial taxa differences in nursing-home residents. DM status did not influence the relationship between the GNRI and gut microbiota in this population. Full article
Show Figures

Figure 1

17 pages, 9139 KB  
Article
Hydromorphological Restoration and Macroinvertebrate Response in a Mountain River: A Case Study from the Upper Raba River
by Renata Kędzior and Natalia Michnowska
Sustainability 2026, 18(12), 6266; https://doi.org/10.3390/su18126266 - 18 Jun 2026
Viewed by 261
Abstract
River restoration is increasingly promoted as a nature-based solution, but evidence of its ecological effectiveness in mountain gravel-bed rivers remains limited. Macroinvertebrate responses to hydromorphological restoration are variable and are still rarely evaluated using an integrated approach combining taxonomic, biotic index, and trait-based [...] Read more.
River restoration is increasingly promoted as a nature-based solution, but evidence of its ecological effectiveness in mountain gravel-bed rivers remains limited. Macroinvertebrate responses to hydromorphological restoration are variable and are still rarely evaluated using an integrated approach combining taxonomic, biotic index, and trait-based components. This study examined whether the hydromorphological restoration of the upper Raba River was associated with measurable environmental and ecological differences between the restored and unrestored sections. Six river sections were analyzed, including three restored and three unrestored sections. The environmental characterisation included hydromorphological and physicochemical variables. Benthic macroinvertebrates were sampled in shallow marginal and main-current habitats, and the analyses included assemblage metrics, biotic indices, taxonomic composition, indicator taxa, and functional traits. The restored sections showed greater channel complexity, including a larger active channel zone, a larger number of active channels, and a coarser substrate. These differences were accompanied by higher Shannon diversity, higher values of the Polish Biological Monitoring Working Party index (BMWP-PL), a higher percentage of individuals of Ephemeroptera, Plecoptera and Trichoptera (%EPT), distinct assemblage composition, and shifts in indicator taxa and selected functional traits. The results highlight the value of multidimensional assessment frameworks to evaluate the effects of restoration on mountain rivers. Full article
(This article belongs to the Special Issue Sustainable Environmental Analysis of Soil and Water—2nd Edition)
Show Figures

Figure 1

19 pages, 3283 KB  
Article
Diversity and Community Composition of Light-Attracted Canopy Insects and Their Relationship with Neutral Genetic Diversity of Tilia cordata (Mill.) in Protected Forests of Lithuania
by Jūratė Lynikienė, Rita Verbylaitė, Artūras Gedminas, Valeriia Mishcherikova, Adas Marčiulynas and Virgilijus Baliuckas
Diversity 2026, 18(6), 378; https://doi.org/10.3390/d18060378 - 17 Jun 2026
Viewed by 289
Abstract
Temperate broadleaved forests support diverse arthropod communities, but canopy-dwelling insects in European lime (Tilia cordata Mill.) stands are still poorly known. We surveyed light-attracted canopy insects in six T. cordata Genetic Conservation Units and related protected stands across Lithuania. One modified, solar-powered [...] Read more.
Temperate broadleaved forests support diverse arthropod communities, but canopy-dwelling insects in European lime (Tilia cordata Mill.) stands are still poorly known. We surveyed light-attracted canopy insects in six T. cordata Genetic Conservation Units and related protected stands across Lithuania. One modified, solar-powered UV light trap was installed in the canopy (10–15 m) at each site and operated twice per month from June to August in 2023 and 2024. We used diversity metrics, similarity indices, multiple regression, and non-metric multidimensional scaling (NMDS) together with PERMANOVA to examine the structure of insect communities and assess the influence of environmental factors. In total, 6031 individuals representing 295 insect species were recorded, with higher abundance, species richness and Shannon diversity in 2024 than in 2023. Across both years and all sites, Shannon H diversity index ranged from 3.21 to 3.92. Sørensen indices indicated moderate species similarity among sites and distinct species composition at the Ukmergė genetic reserve. The 20 most abundant taxa comprised over 60% of all individuals, and dominance structure changed markedly between years: Serica brunnea dominated in 2023 but was nearly absent in 2024. Regression revealed a significant positive effect of air temperature on insect abundance (about a 31% increase per 1 °C), while precipitation had no significant effect on insect abundance. NMDS and PERMANOVA showed strong spatial structuring, with sites explaining most of the variation, and weaker but significant temporal and site-by-year effects. Overall, insect diversity metrics showed non-significant correlations with T. cordata genetic diversity parameters. Results demonstrate that mature T. cordata forest stands are important reservoirs of canopy insect diversity and highlight pronounced spatial heterogeneity, interannual dynamics, and temperature sensitivity of canopy assemblages in Lithuanian forests. Full article
Show Figures

Figure 1

23 pages, 4391 KB  
Article
Characterization of the Oral Microbiome and Anticipated Functional Profiles of Companion Animals in Private and Cohabiting Environments: A Pilot Study
by Charinya So-In, Nisachon Chaowang, Phimchaya Srisomporn, Phiramada Anu-an, Supreeya Paiboon, Sirinan Thananchai, Charinthip Ninolo, Phitcharat Sunthamala, Sujira Maneerat, Sunanta Chuncher, Priyapa Najomtien, Surasak Khankhum and Nuchsupha Sunthamala
Animals 2026, 16(12), 1882; https://doi.org/10.3390/ani16121882 - 17 Jun 2026
Viewed by 374
Abstract
The intricate interaction of a host’s microbiome, the microbiomes of other hosts, and environmental microbial populations significantly impacts host health, given the essential physiological functions the microbiome performs within the organism. The oral microbiome of domesticated animals is also influenced by a variety [...] Read more.
The intricate interaction of a host’s microbiome, the microbiomes of other hosts, and environmental microbial populations significantly impacts host health, given the essential physiological functions the microbiome performs within the organism. The oral microbiome of domesticated animals is also influenced by a variety of host and environmental factors. This study investigated the characteristics of the oral microbiome of dogs and cats under comparable and disparate living conditions, emphasizing the description of diversity patterns, taxonomic composition, and predicted functional profiles. Oral buccal swabs were collected from four groups of companion animals (n = 5 per group): dogs housed alone in single-pet households (Group A), dogs cohabiting with cats in multi-pet households (Group B), cats cohabiting with dogs from the same households (Group C), and cats housed alone in single-pet households (Group D). The cohabiting groups were derived from five multi-pet households, with one dog and one cat sampled from each household. Amplicon sequence variations (ASVs) were used for downstream analysis after 16S rRNA gene sequencing. Rarefaction curve behavior indicated proper sequencing depth. Alpha diversity varied by group (Shannon index, p = 0.045), with Groups C and D having larger diversity. A Beta diversity study revealed community composition differences (Bray–Curtis dissimilarity, R2 = 0.257, p = 0.001), with some overlap between groupings. In all samples, Proteobacteria, Firmicutes, Bacteroidota, and Fusobacteriota dominated the microbiome. The relative abundance of Fusobacterium, Porphyromonas, and Pasteurella varied across groups. Core microbiome analysis identified limited overlap of core ASVs between groups, with most taxa being group-specific. Functional prediction using PICRUSt2 suggested differences in predicted metabolic and cellular pathways. Overall, these exploratory findings suggest that the oral microbiome of companion animals may be influenced by host species and cohabitation conditions. Although limited by the small sample size, the study provides preliminary insights into microbial diversity, community structure, and predicted functional profiles that may inform future One Health-oriented investigations. Full article
(This article belongs to the Section Companion Animals)
Show Figures

Figure 1

24 pages, 2207 KB  
Article
Modeling the Environmental Drivers of Understory Diversity and Rarity in Chestnut (Castanea sativa L.) Forests: The Role of Microclimatic Buffering and Stand Structure
by Lydia-Maria Petaloudi and Petros Ganatsas
Diversity 2026, 18(6), 376; https://doi.org/10.3390/d18060376 - 17 Jun 2026
Viewed by 322
Abstract
Understory vegetation communities in chestnut (Castanea sativa L.) forests feature unique biodiversity patterns and high conservation value, yet the complex drivers of these communities remain poorly quantified. This study investigates the combined effects of structural, microclimatic, and topographic parameters on understory biodiversity [...] Read more.
Understory vegetation communities in chestnut (Castanea sativa L.) forests feature unique biodiversity patterns and high conservation value, yet the complex drivers of these communities remain poorly quantified. This study investigates the combined effects of structural, microclimatic, and topographic parameters on understory biodiversity in the mountainous region of Chalkidiki, Northern Greece. Using a nested plot design (n = 30), we integrated analytical in situ microclimatic monitoring with hemispherical photography (HemiView canopy image analysis system) to accurately quantify canopy architecture (canopy cover and solar radiation parameters), while a detailed vegetation inventory of vascular plants was performed to determine plant community structure and composition. Generalized Additive Models (GAMs) were employed to model Shannon Diversity (H’) and a weighted rarity index (RSR) representing complementary aspects of understory biodiversity. Our results reveal that the tree slenderness of the dominant stand serves as a robust proxy for stand competition and compactness. Lower slenderness values, reflecting reduced overstory competition, were significantly associated with enhanced light availability and potentially with microclimatic stability, which in turn supported higher levels of species diversity and rarity. Distinct ecological trends were observed between diversity and rarity. Shannon diversity was highest in closed forest environments characterized by lower temperatures, low stand slenderness values, southern aspects, and lower elevations, with the final model explaining 66.1% of the variance (n = 27). In contrast, species rarity was primarily driven by stand slenderness and low disturbance levels (explaining 54.6% of the variance), with the majority of rare species occurring in undisturbed stands (n = 30). These findings suggest that targeted, low-intensity management for competition promotes structurally stable stands and microclimatic buffering, facilitating the preservation of understory biodiversity. Full article
Show Figures

Figure 1

21 pages, 5963 KB  
Article
A 15-Day Grazing–15-Day Rest Regime Promotes Plant Diversity and Leaf-Trait Responses in an Alpine Shrub Meadow of the Qilian Mountains, Northeastern Qinghai–Tibet Plateau
by Haijie Zhao, Shaochong Wei, Liang Mao, Qiang Li and Xiaojun Yu
Plants 2026, 15(12), 1879; https://doi.org/10.3390/plants15121879 - 17 Jun 2026
Viewed by 245
Abstract
Alpine shrub meadows on the Qinghai–Tibet Plateau are key warm-season pastures that support pastoral production and ecosystem stability in fragile high-elevation regions. Due to low temperatures, short growing seasons, and slow vegetation recovery, these pastures are highly sensitive to inappropriate grazing management. However, [...] Read more.
Alpine shrub meadows on the Qinghai–Tibet Plateau are key warm-season pastures that support pastoral production and ecosystem stability in fragile high-elevation regions. Due to low temperatures, short growing seasons, and slow vegetation recovery, these pastures are highly sensitive to inappropriate grazing management. However, the effects of different grazing–rest time configurations on plant community composition and leaf functional traits in alpine shrub meadows remain insufficiently understood. In this study, we evaluated five grazing treatments in an alpine shrub meadow in Sunan County, central–eastern Qilian Mountains: 10 days grazing–20 days rest (T1), 15 days grazing–15 days rest (T2), 20 days grazing–10 days rest (T3), continuous grazing (CG), and grazing exclusion (CK). In the third year of treatment implementation, we measured the community diversity, species importance values, and leaf functional traits of four dominant species: Elymus nutans, Carex tibetikobresia, Oxytropis kansuensis, and Bistorta vivipara. T1 and T2 significantly increased species richness, Shannon–Wiener diversity, and Simpson diversity compared with CG and CK. NMDS and PERMANOVA further showed significant differences in overall community composition among grazing treatments. Grazing generally reduced the leaf length, leaf width, and leaf area, whereas T2 showed relatively stronger leaf recovery among grazing treatments. Specific leaf area, specific leaf weight, and leaf length–width ratio showed higher variability and calculated plasticity than leaf thickness and leaf dry matter content, suggesting that resource-acquisition and morphological traits were more responsive to grazing than conservative structural traits. The coefficient of variation of leaf traits was positively associated with the plasticity index, although this association should be interpreted cautiously because both indices were calculated from the same underlying trait dataset. Overall, under the conditions of this three-year, single-site experiment and a target moderate grazing intensity, the 15-day grazing–15-day rest regime performed best among the tested treatments. This regime may provide a practical reference for rotational grazing management in similar warm-season alpine shrub meadows, but its broader applicability requires further validation across different grassland types, grazing intensities, climatic conditions, and longer monitoring periods. Full article
(This article belongs to the Section Plant Ecology)
Show Figures

Figure 1

18 pages, 1957 KB  
Article
Investigation of the Effect of TiO2 as a Dietary Marker on Broiler Intestinal Fermentation: Combination of Ex Vivo Simulation and In Vivo Approach
by Ali Kiani, German Jurgens, Gemma Gonzalez-Ortiz, Carrie L. Walk and Teemu Rinttilä
Animals 2026, 16(12), 1867; https://doi.org/10.3390/ani16121867 - 17 Jun 2026
Viewed by 321
Abstract
The impact of dietary inert digestibility markers on gut microbiota and intestinal fermentation remains poorly understood. This study investigated the effects of dietary titanium dioxide (TiO2) supplementation at 4 kg/t feed, representing a typical dose used in animal nutrition studies, on [...] Read more.
The impact of dietary inert digestibility markers on gut microbiota and intestinal fermentation remains poorly understood. This study investigated the effects of dietary titanium dioxide (TiO2) supplementation at 4 kg/t feed, representing a typical dose used in animal nutrition studies, on fermentation dynamics and microbial composition in broiler chickens using combined ex vivo and in vivo approaches. Ex vivo fermentations were conducted using ileal and caecal microbiota and substrates collected from 32-day-old broiler chickens. Titanium dioxide (TiO2) was supplemented directly to the fermentations, and gas production and short-chain fatty acid (SCFA) profiles were used as the main outcome measures. In parallel, 392 broiler chickens were fed diets with or without TiO2 for 32 days, and ileal and caecal digesta were analysed for fermentation end-products and microbial composition using shotgun metagenomic sequencing. A second ex vivo experiment was performed using microbiota adapted to dietary TiO2. In the first ex vivo model, TiO2 reduced gas production and acetic acid concentration in the ileum (p < 0.05), whereas in the caecum it increased gas production, total eubacterial counts, and branched-chain fatty acids (BCFAs) (p < 0.05). In vivo, TiO2 did not affect growth performance or organ development but significantly increased isobutyric acid and total BCFA concentrations in the caecum (p < 0.05). Metagenomic analysis revealed increased caecal alpha diversity (Shannon index) and enrichment of taxa associated with amino acid metabolism, including Massilicoli timonensis, Blautia merdavium, Rubneribacter badeniensis, and Mediterraneibacter caccavium. The second ex vivo experiment showed similar trends, with increased gas and BCFA production. Collectively, these findings indicate that TiO2 can modulate intestinal fermentation and microbial composition in a segment-specific manner, suggesting that dietary markers may not be biologically inert. Full article
(This article belongs to the Section Animal Nutrition)
Show Figures

Figure 1

18 pages, 2597 KB  
Article
Functional Traits of Trees and Shrubs Drive Soil Carbon Storage in Rocky Desertification Areas via Direct and Fungal-Mediated Pathways
by Xi Li, Wanzhi Qiao, Jicun Bao, Yue Li, Jijie Wang, Aluo An, Jiashun Luo and Wen Zhang
Forests 2026, 17(6), 698; https://doi.org/10.3390/f17060698 - 15 Jun 2026
Viewed by 279
Abstract
Vegetation restoration is an effective measure to improve soil carbon storage in rocky desertification areas. However, the underlying mechanisms driving differences in soil carbon storage among different vegetation types remain unclear. In this study, we selected four typical vegetation types (monospecific broadleaf plantation, [...] Read more.
Vegetation restoration is an effective measure to improve soil carbon storage in rocky desertification areas. However, the underlying mechanisms driving differences in soil carbon storage among different vegetation types remain unclear. In this study, we selected four typical vegetation types (monospecific broadleaf plantation, mixed conifer–broadleaf plantation, monospecific coniferous plantation, and natural shrubland) from the comprehensive control zone for moderately rocky desertification of Xuyong County in the Chishui River Basin. We investigated the effects of vegetation patterns on soil carbon storage through tree layer functional traits, tree diversity, shrub layer functional traits, shrub diversity, and soil fungal/bacterial diversity. The results showed that soil carbon storage was highest in monospecific broadleaf plantations, followed by mixed conifer–broadleaf plantations, then natural shrubland, and it was lowest in monospecific coniferous plantations. Significant differences were mainly observed in the 0–10 cm and 10–20 cm soil layers, while no significant difference was found in the 20–30 cm layer. Tree layer community-weighted mean of leaf nitrogen content, soil fungal Shannon–Wiener index, and shrub layer community-weighted mean of specific leaf area were the core positive drivers of soil carbon differentiation. Among these, tree layer community-weighted mean of leaf nitrogen content was the most important factor, whereas the regulatory effect of shrub layer community-weighted mean of specific leaf area intensified with increasing soil depth. Furthermore, tree layer community-weighted mean of leaf nitrogen content and shrub layer community-weighted mean of specific leaf area not only directly promoted soil carbon accumulation but also indirectly promoted it by enhancing soil fungal diversity. In contrast, the effects of tree and shrub layer diversity and soil bacterial diversity were negligible. This study demonstrates that increasing soil carbon storage in rocky desertification ecosystems depends on the direct effect of soil fungal diversity, as well as the direct effects of tree and shrub layer functional traits and their indirect effects via regulating soil fungal diversity. We recommend that in moderately rocky desertified areas, priority should be given to tree species with high leaf nitrogen content; on sites unsuitable for afforestation, promoting natural shrublands with high specific leaf area can effectively enhance carbon sequestration capacity. Full article
(This article belongs to the Section Forest Soil)
Show Figures

Figure 1

22 pages, 2271 KB  
Article
Effect of Intercropping Paulownia with Spring Barley on Biodiversity in Agroecosystems Under Polish Conditions
by Marek Liszewski, Małgorzata Woźniak, Anna Jama-Rodzeńska, Jacek Twardowski, Iwona Gruss, Ewa Tendziagolska, Piotr Kuc, Elżbieta Gębarowska, Dariusz Zalewski and Bernard Gałka
Sustainability 2026, 18(12), 6028; https://doi.org/10.3390/su18126028 - 12 Jun 2026
Viewed by 213
Abstract
The study evaluated the effect of intercropping Paulownia (Paulownia spp.) with spring barley (Hordeum vulgare L., cv. KWS Thalis) on selected components of agroecosystem biodiversity under Polish conditions. A field experiment established in 2019 compared an alley cropping system with barley [...] Read more.
The study evaluated the effect of intercropping Paulownia (Paulownia spp.) with spring barley (Hordeum vulgare L., cv. KWS Thalis) on selected components of agroecosystem biodiversity under Polish conditions. A field experiment established in 2019 compared an alley cropping system with barley monoculture during the 2025 growing season. Weed infestation, soil microbial communities, mesofauna abundance, and crop yield were assessed. Weed abundance was lower in the intercropping system than in monoculture, reaching 5.6 vs. 15.6 plants m−2 at BBCH 21 and 21 and 22.8 vs. 35.6 plants m−2 at BBCH 75. Bacterial alpha diversity was significantly higher under intercropping conditions, with Shannon index values ranging from 5.12 to 5.25, compared with 4.98–5.09 in monoculture. Fungal diversity showed moderate differences between systems, whereas the abundance of Collembola and Acari was influenced mainly by seasonal variation rather than by cultivation system. No significant reduction in barley yield was observed under intercropping conditions. The results suggest that Paulownia-based alley cropping may reduce weed pressure and support selected soil biological properties without negatively affecting crop productivity. However, the observed responses varied depending on the analyzed parameter and sampling period, indicating the preliminary and context-dependent character of the results. Further long-term studies are required to better understand the ecological mechanisms operating in such agroforestry systems. Full article
Show Figures

Figure 1

14 pages, 12594 KB  
Article
The Effects of Different Organic Amendment Strategies on Soil Properties and Microbial Communities in Maize Monocropping
by Ming Fang, Jianan Sun, Xinyue Li, Jiaming Zhang, Chuyi Wang, Shuxuan Qi, Yixin Guan, Qiang Lyu, Gang Yang, Man Ao, Yubo Zhu and Bo Li
Plants 2026, 15(12), 1805; https://doi.org/10.3390/plants15121805 - 11 Jun 2026
Viewed by 246
Abstract
The black soil layer has undergone substantial degradation in Northeast China, and it is crucial to adopt reasonable tillage measures to prevent black soil degradation. Organic amendment strategies provide an effective solution for mitigating nutrient loss in black soil; meanwhile, there is still [...] Read more.
The black soil layer has undergone substantial degradation in Northeast China, and it is crucial to adopt reasonable tillage measures to prevent black soil degradation. Organic amendment strategies provide an effective solution for mitigating nutrient loss in black soil; meanwhile, there is still a lack of systematic investigation into their impact on soil microbial communities. Thus, we carried out a five-year field experiment from 2020 to 2025 in Jilin Province. Four organic amendment strategies were set up: conventional tillage (CT); straw returning (SR); straw returning + inorganic fertilizer (SRI); and straw returning + inorganic fertilizer + organic fertilizer (SRIO). Furthermore, we investigated the effects of organic materials on soil properties and microbial communities during the maize seedling stage. The results showed that SR significantly increased the relative abundance of Bradyrhizobium, Tausonia and Coprinopsis, while SRI led to a 140.3% increase in Nocardioides. In SRIO treatment, Gaiella and Fusarium were significantly enriched by 103.9% and 142.5%, respectively. Moreover, SR treatment significantly decreased the fungal Shannon and Simpson index by 18.8% and 4.2%, respectively. Organic matter, alkali nitrogen, and available potassium were the primary environmental factors shaping both bacterial and fungal community structures. Additionally, the co-occurrence network suggested that straw returning promoted more diverse interactions among soil bacterial and fungal communities. Our study highlights the potential of organic amendment strategies in enhancing black soil nutrients, as well as their important role in maintaining soil microbial function and stability. Full article
Show Figures

Figure 1

Back to TopTop