Southwestern China Research Articles

An improved framework for quantifying the contribution of climatic and anthropogenic factors to vegetation dynamics - A case study of China

Accurately quantifying the impact of climatic and anthropogenic factors on vegetation change is critical for developing and evaluating ecological management strategies. However, most presented studies typically ignore the climate temporal effects and assume that all pixels are affected by both climate change (CC) and human activities (HA), which often introduce uncertainties. In this study, Leaf area index (LAI), temperature, precipitation, solar radiation, and land cover data from 1982 to 2020 were used to detect and attribute vegetation dynamics in China. We used partial correlation analysis, generalize linear model, trend analysis, and improved RESTREND to analyze the spatiotemporal variation characteristics of vegetation LAI from 1982 to 2020 and to quantify the effects of CC and HA on vegetation dynamics since the implementation of the Grain for Green Project (GGP). The results indicate that significant vegetation greening appeared in most areas (66.2%) between 2000 and 2020. Both CC and HA have positive effects on vegetation greening. In arid and semi-arid regions, precipitation was the primary driver of vegetation change, while in high-latitude areas of southern and southwestern China, temperature was the primary determinant. After considering the temporal effects, the explanatory power of climate variables for vegetation dynamics increased by 4.0% compared to ignoring the temporal effects, accounting for 72.81%. After dividing the pixels into those affected by CC and those affected by both CC and HA, the contribution of HA was decreased from 31.19% to 25.96%. Although the contribution of HA is lower than that of CC, ecological engineering has effectively promoted vegetation greening. These research findings provide scientific data and theoretical basis for ecological environment protection and natural resource management.

A Study on the Prevalence of Osteoporosis in People with Different Altitudes in Sichuan, China.

Osteoporosis is a major health concern among the elderly, underscoring the importance of investigating its prevalence across different geographical regions. There is a current research gap regarding the incidence of osteoporosis and its variation by altitude within Sichuan, China. This study aimed to assess the prevalence of osteoporosis among populations residing at different altitudes in western Sichuan Province. This study utilized data from a population-based cohort in Sichuan, China. Representative locations were selected, and cluster random sampling was employed to conduct cohort studies across multiple sites in southwestern China. T Baseline data were collected from populations in Mianzhu, Kangting, and Sertar between July 2020 and August 2021. To assess differences in osteoporosis incidence among populations at different altitudes and with varying characteristics, we applied Chi-square and rank-sum tests. The study involved 4074 participants, including 1404 males (34.46%) and 791 individuals diagnosed with osteoporosis (19.42%). The prevalence of osteopenia in mid-altitude and high-altitude regions was 20.05% and 16.28%, respectively, while the prevalence of osteoporosis was significantly different, at 25.85% in mid-altitude areas compared to 13.00% in high-altitude areas (P < 0.001). Further analysis identified statistically significant differences in the prevalence of osteopenia and osteoporosis among females (P<0.001), middle-aged (P=0.015) and elderly populations (P=0.038), as well as among individuals who were underweight (P=0.011), normal weight (P<0.001), overweight (P<0.001), and obese (P=0.038). As altitude increased, the prevalence of osteoporosis decreased in all groups except the elderly, while the prevalence of osteopenia decreased among women and across various BMI categories, but increased among middle-aged and elderly individuals. Additionally, in high-altitude regions, Kangting recorded an 18.10% prevalence of osteopenia and a 14.26% prevalence of osteoporosis, compared to Sertar, which exhibited a 6.54% prevalence of osteopenia and a 6.23% prevalence of osteoporosis, indicating significant differences (P<0.001). This study demonstrates that higher altitudes are associated with a decreased prevalence of osteopenia and osteoporosis, particularly among females and middle-aged individuals. These results emphasize the importance of developing region-specific osteoporosis prevention strategies.

Ophiorrhizaliuyanii (Rubiaceae), a new species from south-western China and northern Vietnam.

Ophiorrhizaliuyanii, a new species from south-western China and northern Vietnam, is described and illustrated. The new species is characterised by the glabrous surfaces on almost all plant parts, congested inflorescences and broad-ovate to ovate bracts 9-22 × 4-11 mm. It morphologically differs from the closest species, O.baviensis, mainly in most plant parts being glabrous, bracts broad-ovate to ovate, apex acute or sometimes obtuse, corollas inside with a ring of white hairs at the middle and anthers inserted near the middle in long-styled flowers. According to IUCN Categories and Criteria, O.liuyanii is assessed as Least Concern (LC).

Impacts of Bedrocks on Vegetation Carbons in Typical Karst Areas: A Case Study in Puding County, Southwest China

An accurate estimation of vegetation carbon pools and their carbon sequestration potential is significant in global carbon cycle research but the existing estimations are still insufficient and largely uncertain. Here, we estimated the vegetation carbon density, carbon stocks, and carbon sequestration potential under three main bedrock types (limestone, dolomite, and non-carbonate) in Puding County, Guizhou Province, Southwestern China. The data used here included high-resolution vegetation maps of Puding, data from 274 sample plots, and the carbon contents measured previously in adjacent areas. The land area ratio of natural vegetation at an early stage (namely, grassland and shrub, excluding artificial forests and cultivated land) in carbonate rock areas is significantly larger than that in non-carbonate areas. The average existing carbon densities of vegetation in the non-carbonate, limestone, and dolomite areas were 31.59 ± 7.43, 16.75 ± 4.12, and 8.26 ± 2.45 Mg·ha−1, respectively, while their existing carbon stocks were 752.37 ± 172.85, 855.69 ± 210.65, and 208.49 ± 61.82 Gg, respectively. The maximum vegetation carbon densities of mature forests in the three bedrock types were 156.49 ± 12.92, 130.27 ± 6.05, and 117.41 ± 30.03 Mg·ha−1, respectively. Then, their average vegetation carbon sequestration potentials were 56.07 ± 23.06, 70.13 ± 11.39, and 59.11 ± 33.00 Mg·ha−1, respectively. In other words, vegetation carbon stocks in the non-carbonate, limestone, and dolomite areas increased by 1.34 ± 0.42, 3.58 ± 0.48, and 1.49 ± 0.51 Tg, respectively, after continuous evolution to mature forests. In conclusion, the potential growth of carbon density for karst vegetation is slightly higher than that of non-karst vegetation, despite its lower existing carbon density. Additionally, natural vegetation has a greater potential for carbon sequestration than plantations on all three bedrock types.

Prevalence and Genetic Variation Investigation of the Pseudorabies Virus in Southwest China.

In 2022, a significant PRV outbreak in a southwestern China pig farm led to a high incidence of sow abortion. A serological analysis using gE antigen-based ELISA revealed a high prevalence (69.30%) of PRV gE antibodies among the affected pigs, with a significant variation across different pig populations (1.11-76.12%). We collected additional 5552 pig serum samples and 580 pig cerebrospinal fluid (CSF) samples from various pig farms in Southwest China between 2022 and 2024. The seropositive rates for PRV gE antibodies ranged from 2.36% and 8.65% in the serum samples, while the positive detection rates for the PRV gE gene in the cerebrospinal fluid samples, as determined by PCR, were between 1.06% and 2.36%. The PCR analysis and sequencing of the PRV gB, gC, gE, and TK genes from eight randomly selected samples identified two distinct strains, CQ1 and CQ2. CQ1's gC gene showed similarity to the vaccine strain Bartha, while the other genes aligned with Chinese classical strains, suggesting its potential genetic recombination. CQ2 aligned with the Chinese classical strain SC. Although the overall PRV infection in Southwest China's pig farms is relatively low, occasional outbreaks with high positivity rates are observed. These findings highlight the necessity for increased surveillance and stringent control measures to safeguard the swine industry.

Leguminous Green Manure Intercropping Promotes Soil Health in a Citrus (Citrus reticulata) Orchard

The intercropping of green manure is an important and sustainable production method in citrus orchards (Citrus reticulata). However, few studies focus on the impact of annual and perennial green manure on soil health, particularly soil microbiome and properties in acid soil. Our research objective was to explore the potential effects on soil health by intercropping with annual and perennial leguminous green manures in acid soil citrus orchards of southwestern China. The leguminous green manures used were alfalfa (Medicago sativa) and hairy vetch (Vicia villosa). The results showed that intercropping with green manure increased the total nitrogen, nitrate nitrogen, and available phosphorous in the soil by 48.67~74.67%, 50.00~96.67%, and 44.48~45.04%, respectively. Intercropping with alfalfa significantly increased the activity of soil sucrase 63.75%, and intercropping with hairy vetch increased the activity of β-1,4-glucosidase 44.38% in the soil compared to the monoculture treatment. Intercropping hairy vetch and alfalfa altered the diversity and composition of the soil microbial community and enriched the soil with beneficial fungi and bacteria, including Mortierella and Streptomyces. The richness increased by 58.72% and 17.90% in alfalfa intercropping treatment. In conclusion, intercropping leguminous green manure improved the nutrients and activity of the enzymes in the soil and enriched the antagonistic microbiome in the soil, promoting soil health in the citrus orchard.

Nine new spider species of Belisana Thorell, 1898 (Araneae, Pholcidae) from karst caves, with a list of species of the genus from Guizhou, southwestern China.

Species of the spider genus Belisana Thorell, 1898 exhibit high diversity in Guizhou, southwestern China. Previously, only eight species of Belisana were recorded in Guizhou. In this study, nine new species are described from karst caves: Belisanabijie Wang, S. Li & Yao, sp. nov., B.liupanshui Wang, S. Li & Yao, sp. nov., B.majiang Wang, S. Li & Yao, sp. nov., B.nayong Wang, S. Li & Yao, sp. nov., B.qixingguan Wang, S. Li & Yao, sp. nov., B.xiuwen Wang, S. Li & Yao, sp. nov., B.yongcong Wang, S. Li & Yao, sp. nov., B.zhouxi Wang, S. Li & Yao, sp. nov., and B.zunyi Wang, S. Li & Yao, sp. nov. Belisanazhangi Tong & Li, 2007 is reported from Guizhou for the first time. In addition, a list of all species of Belisana from Guizhou is provided.

Identifying complementary conservation and restoration priority areas for plant species

The coverage of protected areas (PAs) remains far from the Kunming-Montreal target and degraded ecosystems are greatly limiting the conservation efficiency of PAs. Therefore, this paper proposes a method to identify conservation and restoration priority areas to supplement existing PAs. A case study was conducted focusing on Yunnan, southwestern China, which intersects with three world biodiversity hotspots. First, the spatial ranges for 3768 representative conservation plant species were mapped using species distribution models. Subsequently, planning units were classified into three restorability categories, namely no-need restoration, potentially restorable and non-restorable units, according to land cover changes between 2000 and 2020. Then, conservation and restoration priority areas were identified by applying a two-step systematic conservation planning process. Finally, replacement cost analysis was applied to compare the effectiveness of existing PAs and the overall 30 % priority areas. Northwestern, southwestern, and southeastern Yunnan have high biodiversity conservation values. Especially in eastern and southeastern Yunnan, large amounts of restoration priority areas were identified. Conservation and restoration priority areas account for 15.80 % and 3.69 % of Yunnan's land, respectively. Compared to existing PAs, conservation priority areas can increase the number of species covered from 2461 to 3277, and further to 3566 when including restoration priority areas. Compared to existing PAs, the mean species coverage in the overall 30 % priority areas has increased from 27.28 % to 72.69 %. Notably, 12.86 % of existing PAs were identified as restoration priority areas. This study indicates that in addition to conservation measures, implementing restoration strategies in high conservation-value areas is equally important.

Morpho-phylogenetic evidence reveals novel species and new records of Nigrograna (Nigrogranaceae) associated with medicinal plants in Southwestern China.

During a survey of saprobic fungal niches in Southwestern China, eighteen ascomycetous collections of Nigrograna (Nigrogranaceae, Pleosporales, Dothideomycetes) were found on dead branches of medicinal plants. These taxa were characterized and identified based on morphological and culture characteristics, and phylogenetic analyses of a combined the internal transcribed spacer region of rDNA (ITS), nuclear large subunit rDNA (28S, LSU), RNA polymerase second-largest subunit (rpb2), nuclear small subunit rDNA (18S, SSU), and translation elongation factor 1-alpha (tef1-α) sequence dataset also confirmed their placement. As a result, four novel species, namely Nigrogranacamelliae, N.guttulata, N.longiorostiolata and N.neriicola were described. Additionally, four new host records of N.acericola, N.magnoliae, N.oleae and N.thymi were introduced. Furthermore, this study addresses the taxonomic status of N.trachycarpi, proposing its synonymy under N.oleae. Detailed illustrations, descriptions and informative notes for each newly identified taxon and novel host record are provided in this study.

Multi-scale analysis of nutrient and environmental dynamics in Hongfeng Lake Southwest China

Traditional linear correlation analysis may not fully capture the true relationship between these variables. Therefore, multi-scale running correlation analysis, such as time-dependent intrinsic correlation (TDIC) and continuous wavelet transform based on Hilbert–Huang transform (HHT), provides valuable insights into local correlations and the evolving relationship between nutrients and environmental factors over time. In this study, we investigated seven environmental factors and four water quality nutrient indicators in deep lakes on the Yungui Plateau in southwestern China. The results revealed that there may be strong correlations between environmental factors and nutrient levels during certain periods, while opposite trends may emerge at other times. These variations in correlation could be attributed to uncertain physical processes, spatial heterogeneity, or the impact of different climatic factors on local hydrological processes. Wavelet analysis indicated that changes in environmental factors lag behind those in nutrient levels, particularly on a cycle of about 12 months. This suggests that changes in environmental factors align with natural patterns after the water body has been polluted. These conclusions underscore the complexity and dynamic nature of the relationship between environmental factors and nutrient levels in water bodies, highlighting the importance of employing advanced analysis techniques to capture this complexity.

Three new wood-inhabiting fungi of Botryobasidium (Cantharellales, Basidiomycota) from subtropical forests of Southwestern China.

The basidiomycete genus Botryobasidium is a resupinate saprotrophic with a global distribution range from coniferous to broad-leaved forest ecosystems. Though numerous species have been reported from Eurasia and North America, few have been described from China. In the current work, phylogenetic analyses of Botryobasidium in China were conducted based on the dataset of the internal transcribed spacer (ITS) regions and the large subunit (LSU) of nuclear ribosomal RNA gene. Maximum likelihood and Bayesian analyses were used to reconstruct the phylogenetic tree, and three new species, namely Botryobasidiumacanthosporum, B.leptocystidiatum and B.subovalibasidium, were described from subtropical forests of Yunnan Province, Southwestern China. Botryobasidiumacanthosporum is characterized by having yellowish white to dark yellow basidiome, clavate to tubular cystidia, and subglobose to globose basidiospores with obtuse spines. Botryobasidiumleptocystidiatum is characterized by having fluffy to arachnoid, greyish white to ivory basidiome, generative hyphae with clamped, tubular cystidia, and subnavicular to navicular basidiospores. While, B.subovalibasidium is characterized by having yellowish to ivory basidiome, subovoid basidia, navicular to suburniform basidiospores, and thick-walled chlamydospores. These three new species are described and illustrated, and the discriminating characters between the new species and their closely related species are discussed. A key to known species of Botryobasidium in China is provided.

Spatiotemporal changes of landslide susceptibility in response to rainfall and its future prediction — A case study of Sichuan Province, China

In recent decades, global warming has significantly altered both the spatial and temporal distribution of rainfall patterns. This change has heightened the risk of rainfall-induced landslides, which are the most prevalent natural disasters in the mountainous regions of southwestern China. These events pose unpredictable and severe threats to the region, making it essential to forecast future rainfall trends and assess how landslide susceptibility will respond to these changes. Understanding these dynamics is crucial for developing effective strategies to mitigate and adapt to the changing rainfall patterns that influence landslides. This study focuses on Sichuan Province, China, and uses annual cumulative rainfall (ACR) as a key dynamic variable to create landslide susceptibility maps (LSMs). The goal is to explore the evolving relationship between rainfall and landslide susceptibility and use future rainfall projections to predict these risks. To achieve this, a historical landslide geospatial database was compiled across five temporal categories: 2000, 2001–2005, 2006–2010, 2011–2015, and 2016–2020. The extreme learning machine (ELM) was applied to generate LSMs for the years 2000 to2020, while an elasticity framework was used to assess how sensitive landslide susceptibility is to rainfall variations. To project future scenarios, a long short-term memory (LSTM) model was employed to project the ACR for 2030, using monthly rainfall data from 2000 to 2020. This projected ACR was then used to estimate future landslide susceptibility. Results showed a marked increase in high landslide susceptibility areas: 5.6 % by 2005, 0.3 % by 2010, 0.2 % by 2015, and 12.9 % by 2020, all relative to the year 2000. The elasticity analysis revealed that from 2000 to 2020, a 1 % change in rainfall would cause an average 1.35 % change in landslide susceptibility. Looking forward to 2030, the projected rise in ACR is expected to lead to a 2.44 % increase in areas of high landslide susceptibility. Multiple validation techniques were applied to ensure reliability and robustness of these findings.

The restoration of karst rocky desertification has enhanced the carbon sequestration capacity of the ecosystem in southern China

The control of rocky desertification is the largest ecological restoration project in southwestern China, but its impact on the carbon sequestration capacity of karst ecosystems is not clear. Therefore, in this paper selects typical subtropical karst areas in Guangxi are selected as the research object, the carbon sequestration potential of the terrestrial ecosystems are quantified, including karst inorganic carbon sinks, and the response of the terrestrial ecosystem carbon sink to rocky desertification restorationis discussed. The results show that (1) the karst inorganic carbon sink flux (CCSF) is 42.75 t CO2/km2/yr, with a total CCS of 491.12 × 104 t CO2, accounting for only 2.5 % of the country's land area and contributing 7.6 % of the karst inorganic carbon sink. (2) The flux of the vegetation organic carbon sink is 380.44 t CO2/km2/yr, and the total amount is 4403.55 × 104 t CO2/yr., Overall, the spatial distribution exhibits a pattern of high in the northwest and low in the northeast. (3) With decreasing rocky desertification area, the magnitude of the terrestrial ecosystem carbon sink has exhibited a corresponding increasing trend. In particular, during 2010–2020, the rocky desertification area decreased by about 0.868 × 104 km2, and the terrestrial ecosystem carbon sink increased by 114.04 t CO2/km2/yr. This article provides a systematic spatial diagnosis of the carbon sequestration potential of terrestrial ecosystems, including karst inorganic carbon sinks, in the karst areas of Guangxi, and reveals their responses to the restoration of karst rocky desertification. This work has strong reference value and significance for the diagnosis and analysis of the carbon neutrality capacity at the national and global levels.

Elevational patterns of bird alpha and beta diversity in Haba Snow Mountain, Southwestern China: Implication for conservation

Understanding environmental patterns of species diversity is essential for nature reserve planning and biodiversity conservation. In this study, we explored the birds’ alpha and beta diversity along the elevational gradients in Haba Snow Mountain Nature Reserve (hereafter, HBSM), a global biodiversity hotspot, and studied which environmental factor is the main driver in explaining alpha and beta diversity patterns. Our results indicated that taxonomic, functional, and phylogenetic alpha diversity consistently exhibited hump-shaped patterns with similar peaks. After controlling for species richness, both functional and phylogenetic alpha diversity increased with elevation, and the peaks at 3400–3700 m. Mean pairwise functional distance remained nearly constant along the elevation band, whereas mean pairwise phylogenetic distance shown hump-shaped pattern, and the predicted MPD peaked at the fifth band (3100–3400 m a.s.l). The functional and phylogenetic structure of bird communities in HBSM were more clustered along the elevation gradients, suggesting environmental filtering likely drove the assembly processes. Additionally, primary productivity (NDVI and/or habitat heterogeneity) and/or precipitation were robust predictors of variation in most diversity metrics. For multiple-site beta diversity, we observed that high turnover component in taxonomic, functional, and phylogenetic dimensions, indicating distinct bird assemblages across various elevational bands. In pairwise beta diversity, the spatial turnover of taxonomic and phylogenetic aspects was higher than nestedness, revealing species replacement occurs relatively frequently between evolutionarily related species with similar niche and functional traits. Overall, our findings highlight the importance of considering both different dimensions and multifaceted diversity when assessing elevational patterns of bird diversity. This study also provides valuable insights into the structuring mechanisms of bird communities and informs conservation planning along elevational gradients in HBSM, and offers a comprehensive case on species richness along elevational gradients.

Development characteristics and hazard analysis of debris flow along the Emei to Mianning section of the Chengdu–Kunming Railway

Geological disasters in the Emei to Mianning section of the Chengdu–Kunming Railway located in southwestern China occur frequently, and many debris flow gullies are distributed along the line. Debris flows often cause damage to the railway and highway that threatens the safe operation of the original line and the double-track line. Along the railway, the debris flow outbreak risks are analyzed for 53 debris flow gullies using field survey, remote sensing interpretation, and numerical simulation. Their developmental characteristics were judged according to the code. The results are used for numerical simulation of debris flow to further determine the movement characteristics and the accumulation range of debris flow. The results are combined with high-definition satellite images to analyze the form of the railway passing from the mouth of the ditch and the simulation results to determine the impact on the safe operation of the Chengdu–Kunming Railway when the debris flow erupts. Finally, disaster prevention and mitigation projects are proposed, and the prevention and control effects of the proposed works are validated.

Hydrological processes in multi-layered aquifers of a karst watershed with coal mining activity: Insights from hydrochemistry and isotopes

Study regionThe Laochang Karst watershed (LCKW) is located in eastern Yunnan Province, southwestern China. It is the representative karst area affected by coal-mining activities in southwestern China. Study focusIdentifying hydrological processes of multi-layered aquifers in karst watersheds is challenging due to complex natural and anthropogenic processes. This study attempts to clarify the hydrological conceptual model of the LCKW using hydrochemistry and D, O, Sr, S, and C isotopes. New hydrological insights for the regionSurface water and multi-layered groundwater have the hydrochemical types of SO4-Ca·Mg, HCO3·SO4-Ca, and HCO3-Ca. Meteoric water and condensate were the major recharge sources. The main processes dominating hydrochemical compositions consist of sulfide oxidative dissolution, carbonate dissolution, positive cation exchange, and agricultural activities. Elevated SO42− concentration in the mine water, river water and shallow coalbed water mainly originated from the oxidation of pyrite in the coal-bearing strata of the Longtan Formation. whereas the deeper layers and groundwater away from the mines were hardly contaminated by SO42− due to the presence of aquiclude. HCO3− concentrations of surface water and multi-layered groundwater were mainly derived from carbonate dissolution and soil CO2, and mine water was also influenced by atmospheric CO2. Positive cation exchange contributed to increasing Na+ concentration. Agricultural activities contributed NO3−, Cl−, and K+ ions in aquifers, especially near large karst fallout caves. A hydrological model of multi-layered aquifers in the LCKW was built based on the above results. These findings will provide valuable guidance for understanding the hydrological processes of complex karst watersheds worldwide.

Endangered Taxus wallichiana var. wallichiana—Its Forest Characteristics, Population Structure, and Regeneration Status in Yunnan, Southwestern China

The survival of relict Taxus wallichiana var. wallichiana (Yunnan yew) is threatened by overexploitation for its quality wood and medicinal properties, particularly for taxol extraction. Understanding the current status of its communities and populations is crucial for protecting existing natural forest resources. We established 53 vegetation plots in Yunnan, southwestern China, where T. wallichiana var. wallichiana is the primary dominant species. These plots were classified into four forest types. The forests were multi-stratified, with T. wallichiana var. wallichiana frequently dominating the subcanopy and shrub layer. Species diversity indices did not significantly differ among the four forest types. The age structure of T. wallichiana var. wallichiana exhibited a multi-modal pattern, with a maximum age of 1165 years. Growth was slow, with an average radial growth rate of 0.78 mm/year. Despite its strong sprouting ability, the species had a poor seedling/sapling bank and suffered from inadequate regeneration. Its seedlings/saplings are shade-intolerant. This study provides a scientific basis for effective conservation strategies, emphasizing the need for in situ regeneration to ensure the survival of T. wallichiana var. wallichiana and its contributions to biodiversity and ecosystem services.

Adaptation of skin structures to environmental variations in anurans from southern and southwestern China.

Variations in skin structures can possibly reflect local adaptation to distinct environmental factors. As the primary interface with the surrounding environment, amphibian skin undergoes phenotypic innovations that play a key role in protection, water absorption, and respiration. However, the effects of environmental factors on skin structures have been examined in only a limited number of species. Here, we conducted a comparative analysis of the skin structures of 102 Chinese anuran species across varying geographical distributions and habitat types. Our results revealed that the total volume of granular glands and capillary density in the dorsal skin significantly increased with increasing latitude. We also found that the thickness of calcified layers in both dorsal and ventral skin was positively correlated with annual temperature and negatively correlated with humidity. Additionally, terrestrial species exhibited the largest dorsal granular gland, whereas arboreal species had the smallest one. Likewise, the largest dorsal mucous gland was observed in aquatic species, while the smallest was found in terrestrial species. These results highlighted the importance of understanding the relationship between skin phenotypes and environmental variables and thus providing conservation strategies based on the evolutionary adaptations in anurans. Our study can contribute to the broader knowledge of evolutionary biology in anurans by demonstrating how specific skin traits are linked to survival and fitness across various ecological contexts.

New species diversity and host association of Lactarius sect. Deliciosi: describing L. gibbosus and L. parvihatsudake (Russulaceae, Russulales) in southern China

Lactarius gibbosus and L. parvihatsudake, two red-colored species of Lactarius sect. Deliciosi are described as new from southern China. Lactarius gibbosus is a rare species, growing in fagaceous forest in southwestern China, similar to L. subindigo. Its pileipellis with slightly thick-walled swollen cells is unique in the section. The macrocystidia filled with golden yellow contents are another good character. This is the first report of red-colored species of L. sect. Deliciosi growing in fagaceous forest. Lactarius parvihatsudake grows in forest of Pseudolarix amabilis, an ancient relict Chinese tree only in eastern China. It has smaller basidiocarps and bigger spores than L. hatsudake. The discovery of this species added Pseudolarix to the potential host list of L. sect. Deliciosi. Phylogenetic analyses of the ITS region and glyceraldehyde-3-phophate dehydrogenase gene showed that L. gibbosus was a sibling of L. subindigo. These two species formed an early diverging lineage of L. sect. Deliciosi. Lactarius parvihatsudake was nested deeply in L. sect. Deliciosi but its closest relatives cannot be determined. These data update our understanding of the diversity of L. sect. Deliciosi in Asia and will hopefully help to understand the role of host shift in speciation of ectomycorrhizal fungi.

A cross-sectional survey on COVID-19 phobia and its influencing factors among undergraduate nursing students

BackgroundThe COVID-19 pandemic has significantly impacted the psychological well-being of undergraduate nursing students in China. It is vital to have an understanding of their COVID-19 phobia and its predictors, especially during transitions in public health policy.ObjectiveThis study aims to evaluate the situation and factors contributing to COVID-19 phobia among nursing students in Southwestern China.MethodsA cross-sectional study was conducted in December 2022 among nursing undergraduates in southwestern China. A convenience sample of 317 undergraduate nursing students from all grades at a medical university in Chengdu was assessed using the COVID-19 Phobia Scale (C19P).ResultsThe mean COVID-19 Phobia Scale (C19P-SC) score was 52.92 (± 13.02), indicating moderate levels of phobia, with gender, chronic disease, and perceived susceptibility being significant predictors. 11.67% of the students reported an infection history, while 81.39% knew an infected individual. Notably, fourth-year students showed significantly higher phobia level than first-year. Gender, chronic disease, perceived susceptibility, and risk significantly predicted COVID-19 phobia, explaining 16.4% of the variance Results of the thematic analysis revealed four main themes related to COVID-19 phobia and career choice among nursing undergraduates: concerns of infection risk, professional commitment, compromise and acceptance, and confronting phobia.ConclusionsThis study discovered a significant level of COVID-19 phobia among undergraduate nursing students and identified several risk factors, including being female, having chronic diseases, perceiving a high susceptibility to the virus, and perceiving a high level of harm after infection. These findings highlight the importance of educators focusing on the mental well-being of nursing students, particularly seniors, to reduce the impact of phobia on their social interactions and career aspirations. This will help ensure that they are well-prepared for their future roles in healthcare.