Circulation pattern and genetic variation of rhinovirus infection among hospitalized children on Hainan Island, before and after the dynamic zero-COVID policy, from 2021 to 2023.

Throughout the COVID-19 pandemic, rhinovirus (RV) remained notable persistence, maintaining its presence while other seasonal respiratory viruses were largely suppressed by pandemic restrictions during national lockdowns. This research explores the epidemiological dynamics of RV infections among pediatric populations on Hainan Island, China, specifically focusing on the impact before and after the zero-COVID policy was lifted. From January 2021 to December 2023, 19 680 samples were collected from pediatric patients hospitalized with acute lower respiratory tract infections (ARTIs) at the Hainan Maternal and Child Health Hospital. The infection of RV was detected by tNGS. RV species and subtypes were identified in 32 RV-positive samples representing diverse time points by analyzing the VP4/VP2 partial regions. Among the 19 680 pediatric inpatients with ARTIs analyzed, 21.55% were found to be positive for RV infection, with notable peaks observed in April 2021 and November 2022. A gradual annual decline in RV infections was observed, alongside a seasonal pattern of higher prevalence during the colder months. The highest proportion of RV infections was observed in the 0-1-year age group. Phylogenetic analysis on 32 samples indicated a trend from RV-A to RV-C in 2022. This observation suggests potential evolving dynamics within the RV species although further studies are needed due to the limited sample size. The research emphasizes the necessity for ongoing surveillance and targeted management, particularly for populations highly susceptible to severe illnesses caused by RV infections.

Geomorphic impacts within Red River Fault and island shifting as witnessed by the phylogeography of the largest water strider.

Palaeogeological events and climate oscillations profoundly impact the demographics and distributions of small-range species, increasing the extinction risk. The largest water strider worldwide, Gigantometra gigas (Hemiptera: Gerridae), exhibits restricted distributions in Vietnam and southern China. Herein, we generated three genomic datasets (mitogenomes, 146 nuclear protein-coding genes and single nucleotide polymorphisms) with ecological niche modelling (ENM) to explicitly test whether the present-day distribution of G. gigas actually resulted from geographical and climatic effects. We found that the origin of this largest water strider reached the divergence time of the genus within Gerridae, providing a greater opportunity to explore its response to geographic movements. The right-lateral motion of the Red River Fault facilitated the divergence of two phylogeographic lineages, resulting in the "north-south component" genetic pattern in G. gigas. The Hainan and southeast Vietnam populations of the southern linage were completely separated by the Beibu Gulf but exhibited similar genetic compositions, confirming that Hainan had a continental origin and that Hainan Island joined with the Indo-China Peninsula to promote gene exchange among populations. Additionally, we noticed the low genetic diversity but long demographic history of the northern lineage, which displayed population dynamics opposite to those of other organisms. Integrating the demographic changes and ENM findings revealed that suitable habitat contraction and rapid demographic decline during the Last Glacial Maximum (LGM) triggered the low genetic diversity of the northern lineage. Overall, the demographic history of the largest water strider was mainly shaped by geographical features, and first provided evidence from the phylogeographic perspective of aquatic insects to support the hypothesis of Hainan Island shifting.

The origin, dissemination, and molecular networks of HIV-1 CRF65_cpx strain in Hainan Island, China.

BACKGROUND: HIV-1 CRF65_cpx strain carries drug-resistant mutations, which raises concerns about its potential for causing virologic failure. The CRF65_cpx ranks as the fourth most prevalent on Hainan Island, China. However, the origin and molecular epidemiology of CRF65_cpx strains in this area remain unclear. This study aims to estimate the spatial origins and dissemination patterns of HIV-1 CRF65_cpx in this specific region. METHODS: Between 2018 and 2021, a total of 58 pol sequences of the CRF65_cpx were collected from HIV-positive patients on Hainan Island. The available CRF65_cpx pol sequences from public databases were compiled. The HIV-TRACE tool was used to construct transmission networks. The evolutionary history of the introduction and dissemination of HIV-1 CRF65_cpx on Hainan Island were analyzed using phylogenetic analysis and the Bayesian coalescent-based approach. RESULTS: Among the 58 participants, 89.66% were men who have sex with men (MSM). The median age was 25 years, and 43.10% of the individuals had a college degree or above. The results indicated that 39 (67.24%) sequences were interconnected within a single transmission network. A consistent expansion was evident from 2019 to 2021, with an incremental annual addition of four sequences into the networks. Phylodynamic analyses showed that the CRF65_cpx on Hainan Island originated from Beijing (Bayes factor, BF = 17.4), with transmission among MSM on Hainan Island in 2013.2 (95%HPD: 2012.4, 2019.5), subsequently leading to an outbreak. Haikou was the local center of the CRF65_cpx epidemic. This strain propagated from Haikou to other locations, including Sanya (BF > 1000), Danzhou (BF = 299.3), Chengmai (BF = 27.0) and Tunchang (BF = 16.3). The analyses of the viral migration patterns between age subgroups and risk subgroups revealed that the viral migration directions were from "25-40 years old" to "17-24 years old" (BF = 14.6) and to "over 40 years old" (BF = 17.6), and from MSM to heterosexuals (BF > 1000) on Hainan Island. CONCLUSION: Our analyses elucidate the transmission dynamics of CRF65_cpx strain on Hainan Island. Haikou is identified as the potential hotspot for CRF65_cpx transmission, with middle-aged MSM identified as the key population. These findings suggest that targeted interventions in hotspots and key populations may be more effective in controlling the HIV epidemic.

Comparison of common human respiratory pathogens among hospitalized children aged ≤ 6 years in Hainan Island, China, during spring and early summer in 2019-2021.

The coronavirus disease 2019 (COVID-19) pandemic and related public health intervention measures have been reported to have resulted in the reduction of infections caused by influenza viruses and other common respiratory viruses. However, the influence may be varied in areas that have different ecological, economic, and social conditions. This study investigated the changing epidemiology of 8 common respiratory pathogens, including Influenza A (IFVA), Influenza B (IFVB), Respiratory syncytial virus (HRSV), rhinovirus (RV), Human metapneumovirus Adenovirus, Human bocavirus, and Mycoplasma pneumoniae, among hospitalized children during spring and early summer in 2019-2021 in two hospitals in Hainan Island, China, in the COVID-19 pandemic era. The results revealed a significant reduction in the prevalence of IFVA and IFVB in 2020 and 2021 than in 2019, whereas the prevalence of HRSV increased, and it became the dominant viral pathogen in 2021. RV was one of the leading pathogens in the 3 year period, where no significant difference was observed. Phylogenetic analysis revealed close relationships among the circulating respiratory viruses. Large scale studies are needed to study the changing epidemiology of seasonal respiratory viruses to inform responses to future respiratory virus pandemics.

Mitochondrial diversity and genetic structure of common carp (Cyprinus carpio) in Pearl River and Nandujiang River.

Common carp (Cyprinus carpio) is an important valuable cyprinid in China and has been a popular cultured aquaculture species around the globe. Understanding the genetic diversity of wild native common carp not only provides basic data for the protection and utilisation of common carp resources but also assesses the effect of human activities on the genetic diversity of this species. In this study, genetic diversity and population structure of the common carp from 15 sampling populations in the Pearl River and Nandujiang River were determined using a coalescent mitochondrial locus (MLS), including mitochondrial cytochrome b gene (Cytb) and a control region (D-loop) segment. The haplotype diversity and nucleotide diversity were 0.962 and 0.00628 in the Pearl River and 0.808 and 0.00376 in the Nandujiang River, respectively. Phylogenetic and haplotype network analyses indicated that three sub-species (a) C. c. rubrofuscus, (b) C. c. haematopterus and (c) C. c. carpio all occur in both rivers. AMOVA revealed that the variation within populations (86.2%) was the main source of the total variation. Statistically significant genetic differentiation among different Pearl River populations of C. c. rubrofuscus (Fst  = 0.05-0.25) and relatively high genetic differentiation between the Nandujiang River population and the Pearl River populations (Fst  > 0.238) are apparent. Bayesian clustering analyses detected that global populations consisted of eight genetic clusters and examined that Nandujiang River population included relatively pure genetic clusters. Neutrality tests suggested that native populations experienced recent population expansion, and Extended Bayesian Skyline Plot indicated that the common carp populations likely experienced a historical expansion during 0.125-0.250 MYA. Artificial fish propagation and release, escape from fish farms and Fang Sheng may explain the invasion of non-native sub-species in many river sections, such as Laibin, Rongjiang, Huizhou, Heyuan and Zhaoqing. To conserve the native common carp populations, release station should be established to culture native common carp fry. Overall, the findings can be contributed to complementing scientific knowledge for conservation and management of the wild native common carp.

[A real-world study of sofosbuvir-based drug treatment for hepatitis C virus genotype 6 infection in Hainan region of China].

Objective: To explore the real-world effectiveness and safety of sofosbuvir-based regimen for patients with chronic hepatitis C virus (HCV) genotype 6 infection in Hainan Island. Methods: Fifty-three cases with chronic hepatitis C virus (HCV) genotype 6 infection who were initially treated with a sofosbuvir (SOF)-based regimen [sofosbuvir/velpatasvir (SOF/VEL) for 12 weeks or sofosbuvir combined with ribavirin (SOF+RBV) for 24 weeks], followed by 24 weeks of follow-up after discontinuation of the drug from January 2018 to March 2020 were selected. The primary outcome measures were incidence of sustained virological response at 12 weeks (SVR12) after the drug withdrawal. The secondary outcome measures were adverse drug events with sustained virological response at the end of treatment and 24 weeks after the end of treatment. The occurrence of adverse events was observed during the treatment. An intragroup comparison was performed by t-test. Intention-to-treat and modified intention-to-treat analysis was used for sustained virological respons. Results: The subtype distribution of chronic hepatitis C virus (HCV) genotype 6 in 53 cases of chronic hepatitis C infection were as follows: 22 cases of type 6a, 5 cases of type 6w, 5 cases of type 6xa, 3 cases of type 6v, 2 cases of type 6e, 2 cases of type 6r, 1 case of type 6xh, and 13 cases of special virus strains with undetermined genotype. The overall sustained virological response rate at 12 weeks after the drug withdrawal was 100%. Furthermore, HCV RNA was undetectable during the treatment period (4 weeks), at the end of treatment and after the treatment (24 weeks). There were seven cases of adverse events, mainly including fatigue, anorexia, and mild anemia; however, no serious adverse events were reported. Conclusion: Sofosbuvir-based regimen combined with ribavirin or velpatasvir cannot only achieve high response rate to HCV subtype 6a, but also obtain a good sustained virological response to the rare prevalent sub-genotypes and special virus strains of HCV genotype 6, with mild adverse reactions and acceptable safety profile.

Pelistega ratti sp. nov. from Rattus norvegicus of Hainan island.

Two strains (NLN63T and NLN82) of Gram-stain-negative, oxidase- and catalase-positive, bacilli-shaped organisms were isolated from the faecal samples of two separate Rattus norvegicus in Baisha county of Hainan Province, Southern PR China. Phylogenetic analysis based on the near full-length 16S rRNA sequences revealed that strain NLN63T belongs to the genus Pelistega, having maximum similarity to Pelistega suis CCUG 64465T (97.1 %), Pelistega europaea CCUG 39967T (96.2 %) and Pelistega indica DSM 27484T (96.2 %), respectively. The phylogenomic tree built on 553 core genes from genomes of 20 species in the genus Pelistega and other adjacent genera further confirmed that strains NLN63T and NLN82 form a distinct subline and exhibit specific phylogenetic affinity with P. europaea CCUG 39967T. In digital DNA-DNA hybridization analyses, strain NLN63T showed low estimated DNA reassociation values (21.4-22.6 %) with the type strains of the species in the genus Pelistega. The DNA G+C contents of strains NLN63T and NLN82 were 37.3 and 37.1 mol%, respectively. Strain NLN63T had a unique MALDI-TOF MS profile, contained Q-8 as the major quinone and C16 : 0, summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c or both) and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c or both) as the dominant fatty acids. Based upon these polyphasic characterization data obtained from the present study, a novel species of the genus Pelistega, Pelistega ratti sp. nov., is proposed with NLN63T (=GDMCC 1.1697T=JCM 33788T) as the type strain.

Analysis of HCV Isolates Among the Li Ethnic in Hainan Island of South China Reveals Their HCV-6 Unique Evolution and a New Subtype.

BACKGROUND/AIMS: Hainan Island has been inhabited by the "Li" aboriginal minority for centuries where the HCV genotype distribution patterns maybe remarkably different from other parts of China. We aimed to provide a better understanding of the infection with HCV genotype 6 among "Li" aboriginals on Hainan Island. METHODS: Firstly, using RT-PCR and DNA sequencing to determined 517 partial HCV Core-E1(115 from Li Ethnic, 402 from Han Ethnic) and 8 full-length genomes from Li ethnic in Hainan Island successfully, and then using the phylogenetic tree to determine the HCV genotype distribution and analyze the evolution of them. RESULTS: Phylogenetic tree analysis showed that the distribution pattern of HCV genotypes among the Han and Li ethnic population exhibits significant diferences: 6a was the most prevalent subtype in Han ethnic of Hainan Island followed by 1b, 3b, 2a, 3a, and 1a. All genomes from Li ethnic were classified into genotype 6, while 84 out of 115 (73%) could not be classified. Nine sequences (HN1350 et al.) from Li ethnic might be assigned to a new subtype 6xh as their p-distances ranged from 5.9∼9.7%. Furthermore, we sequenced and characterized full-length genomes for eight HCV-6 isolates which were all from Li ethnic in Hainan Island. Among these isolates, the HN1350 was classified as a new subtype: 6xh. CONCLUSION: Overall, we firstly defined a new subtype of genotype 6xh through partial and new full length genome. And we found a unique distribution pattern of HCV 6 in the Li tribe, which might provide a better way to understand the genetic diversity of HCV-6 and to investigate the phylogeny of HCV strains from Li tribe.

Renewed classification within Goniurosaurus (Squamata: Eublepharidae) uncovers the dual roles of a continental island (Hainan) in species evolution.

Continental islands are often dynamic in regard to the origin and evolution of their biota. Although colonizations from mainland Southeast Asia to Hainan Island have been reported, the role of Hainan Island as a source for continental biota has not been considered. Goniurosaurus is a genus comprised of nocturnal ground geckos. We reexamined the evolutionary history of Goniurosaurus using both molecular phylogenetics and morphological comparisons. All phylogenetic trees recovered G. zhoui as sister to G. hainanensis + G. lichtenfelderi, which together are the sister lineage of G. bawanglingensis. The recovery of this "Hainan clade" contradicts previous classifications that placed G. bawanglingensis within the G. luii group. Moreover, ancestral trait reconstruction revealed that body band number might have decreased two or three times independently within Goniurosaurus from four to three. The divergence between the continental G. luii group and the Hainan clade was estimated at ∼34.7 Mya (CI = 22.3-48.6), possibly correlating with the vicariance event between Hainan Island and the mainland. G. lichtenfelderi diverged from G. hainanensis very recently, which might be associated with a historical dispersal event from Hainan Island to Vietnam during glacial periods. Our study improves the understanding of Goniurosaurus systematics and reveals the important role of Hainan Island in bidirectional colonizations.

DNA barcoding reveals insect diversity in the mangrove ecosystems of Hainan Island, China.

Insect diversity is an indicator of environmental conditions. Frequent outbreaks of mangrove pests have threatened the fragile mangrove ecosystem in China and the sustainable utilization of mangrove resources. The understanding of mangrove pests, as well as a fundamental knowledge of insect diversity, in mangrove forests in China has been hindered by the difficulty of morphological species delimitation because captured insect specimens are either larvae or incompletely preserved adults. DNA barcoding technology uses only a small amount of DNA to conduct species identification. Taking advantage of this, we investigated the entomofauna of mangrove forests on Hainan Island by using a barcode combining cytochrome c oxidase subunit I (COI) and cytochrome-b (Cytb). We collected 627 specimens at six localities around the island, which were identified as 219 insect species belonging to 11 orders and 72 families. Lepidoptera, Coleoptera, and Hymenoptera are the most species-rich and abundant taxa. We also identified 13 mangrove pests, 5 parasitoids, and 12 species of predators.

Anthropogenic protection alters the microbiome in intertidal mangrove wetlands in Hainan Island.

Intertidal mangrove wetlands are of great economic and ecological importance. The regular influence of tides has led to the microbial communities in these wetlands differing significantly from those in other habitats. In this study, we investigated the microbiomes of the two largest mangrove wetlands in Hainan Island, China, which have different levels of anthropogenic protection. Soil samples were collected from the root zone of 13 mangrove species. The microbial composition, including key functional groups, was assessed using Illumina sequencing. Bioinformatics analysis showed that there was a significant difference in the microbiomes between the protected Bamen Bay and the unprotected Dongzhai Bay. The overall microbiome was assigned into 78 phyla and Proteobacteria was the most abundant phylum at both sites. In the protected wetland, there were fewer marine-related microbial communities, such as sulfate-reducing bacteria, and more terrestrial-related communities, such as Verrucomicrobia methanotrophs. We also observed distinct microbial compositions among the different mangrove species at the protected site. Our data suggest that the different microbiomes of the two mangrove wetlands are the result of a complex interaction of the different environmental variables at the two sites.

Host feeding patterns of mosquitoes in a rural malaria-endemic region in hainan island, china.

Malaria is endemic in Wangxia Village of Hainan Island. In this area little is known about the host seeking behavior and feeding habit of mosquitoes. Three sites representing the most common habitat types in the village were selected to study the host seeking behavior and feeding habit of mosquitoes. Of the total 9 species belonging to 4 genera (Armigeres, Culex, Aedes, and Anopheles) collected in Wangxia Village, Culex tritaeniorhynchus and Cx. pipiens quinquefasciatus were the most commonly collected species. Armigeres subalbatus and Anopheles sinensis were moderately common species. Blood meal analysis confirmed that Cx. tritaeniorhynchus and Cx. p. quinquefasciatus fed on multiple hosts, mainly poultry but occasionally other animals. Anopheles sinensis, a vector of malaria, fed predominately on cattle hosts, followed by humans. Anopheles maculatus and An. barbirostris fed on both humans and domestic animals. Our results indicate that most mosquitoes in this area preferred domestic animals over humans and showed a tendency to feed on multiple hosts within the same gonotrophic cycle. Therefore, the potential role of domestic animals in arbovirus transmission should be evaluated as part of a strategy for controlling mosquito-borne diseases in this region.

Genomic and phylogenetic profiling of RNA of tick-borne arboviruses in Hainan Island, China.

Ticks act as vectors and hosts of numerous arboviruses. Examples of medically important arboviruses include the tick-borne encephalitis virus, Crimean Congo hemorrhagic fever, and severe fever with thrombocytopenia syndrome. Recently, some novel arboviruses have been identified in blood specimens of patients with unexplained fever and a history of tick bites in Inner Mongolia. Consequently, tick-borne viruses are a major focus of infectious disease research. However, the spectrum of tick-borne viruses in subtropical areas of China has yet to be sufficiently characterized. In this study, we collected 855 ticks from canine and bovine hosts in four locations in Hainan Province. The ticks were combined into 18 pools according to genus and location. Viral RNA-sequence libraries were subjected to transcriptome sequencing analysis. Molecular clues from metagenomic analyses were used to classify sequence reads into virus species, genera, or families. The diverse viral reads closely associated with mammals were assigned to 12 viral families and important tick-borne viruses, such as Jingmen, Beiji nairovirus, and Colorado tick fever. Our virome and phylogenetic analyses of the arbovirus strains provide basic data for preventing and controlling human infectious diseases caused by tick-borne viruses in the subtropical areas of China.

In Vitro Characterization and Identification of Potential Probiotic Yeasts Isolated from Zaopocu, a Traditional Fermented Dregs Vinegar from Hainan Island.

Recently, there has been an increasing interest in researching fermented food-derived yeasts as probiotics because they offer a natural and diverse source of potential strains with unique functional properties and health benefits. In this study, 13 yeast strains isolated from Zaopocu (ZPC), a traditional fermented dregs vinegar on Hainan Island, China, were evaluated for their probiotic characteristics in vitro. Yeast identification was conducted through 5.8S-ITS region sequencing, revealing Kodamaea ohmeri as the predominantly isolated species (ZPC_Y3, Y5, Y6, Y11), followed by Pichia kudriavzevii (ZPC_Y2, Y13, Y14), Rhodotorula mucilaginosa (ZPC_Y9, Y10), Pichia fermentans (ZPC_Y8, Y12), Pichia kluyveri (ZPC_Y4), and Pichia occidentalis (ZPC_Y1). Except for ZPC_Y4, ZPC_Y8, and ZPC_Y12, all isolated yeasts exhibited stable growth at 37 °C. The survival rates of all test strains exceeded 60% under challenging conditions at pH = 2 and 0.3% bile salt, along with strong antioxidant activity (> 5 6%), notable autoaggregation (> 70%), and varying levels of cell hydrophobicity with xylene (ranging from 35.32 ± 8.57% to 89.73 ± 4.84%). In addition, all isolates showed resistance to multiple antibiotics, along with antagonistic activity, and were deemed safe as none exhibited hemolytic, gelatinase, or DNase activities. Significantly, two P. kudriavzevii strains (ZPC_Y2, Y14) exhibited the production of catalase, lipase, and ß-galactosidase, along with the capacity to synthesize gamma-aminobutyric acid (GABA). In summary, this preliminary study represents the first attempt to identify and characterize potential probiotic yeast strains isolated from Zaopocu, providing a theoretical basis for exploring their application in developing novel therapeutic probiotics.

Differences in Albizia odoratissima genetic diversity between Hainan Island and mainland populations in China.

Background: This study aimed at exploring unique population genetic characteristics of Albizia odoratissima (Linn. f) Benth on Hainan Island to provide a scientific basis for its rational utilization and protection. Methods: It analyzed the genetic diversity and structure of 280 individuals from 10 subpopulations of A. odoratissima from Hainan Island and Baise City using 16 expression sequence markers - simple sequence repeat markers. Results: The genetic diversity of Hainan population (I = 0.7290, He = 0.4483) was lower than that of the Baise population (I = 0.8722, He = 0.5121). Compared with the Baise population (Nm = 2.0709, FST = 0.1077), the Hainan Island population (Nm = 1.7519, FST = 0.1249) exhibited lower gene flow and higher degree of genetic differentiation. Molecular variance and genetic differentiation analyses showed that the main variation originated from individuals within the subpopulation. There were significant differences in the genetic structure between Hainan and Baise populations. It grouped according to geographical distance, consistent with the Mantel test results (R2 = 0.77, p = 0.001). In conclusion, the genetic diversity of the island A. odoratissima population was lower than that distributed on land, the two populations exhibited obvious genetic structure differences. Both the degrees of inbreeding and genetic differentiation were higher in the island population than in the land population.

Epidemiology of Human Parainfluenza Virus Infections among Pediatric Patients in Hainan Island, China, 2021-2023.

Human parainfluenza viruses (HPIVs) are the leading causes of acute respiratory tract infections (ARTIs), particularly in children. During the COVID-19 pandemic, non-pharmaceutical interventions (NPIs) significantly influenced the epidemiology of respiratory viruses. This study analyzed 19,339 respiratory specimens from pediatric patients with ARTIs to detect HPIVs using PCR or tNGS, focusing on the period from 2021 to 2023. HPIVs were identified in 1395 patients (7.21%, 1395/19,339), with annual detection rates of 6.86% (303/4419) in 2021, 6.38% (331/5188) in 2022, and 7.82% (761/9732) in 2023. Notably, both the total number of tests and HPIV-positive cases increased in 2023 compared to 2021 and 2022. Seasonal analysis revealed a shift in HPIV prevalence from winter and spring in 2021-2022 to spring and summer in 2023. Most HPIV-positive cases were in children aged 0-7 years, with fewer infections among those aged 7-18 years. Since June 2022, HPIV-3 has been the most prevalent serotype (59.55%, 524/880), whereas HPIV-2 had the lowest proportion (0.80%, 7/880). The proportions of HPIV-1 (24.89%, 219/880) and HPIV-4 (15.45%, 136/880) were similar. Additionally, the incidence of co-infections with other common respiratory pathogens has increased since 2021. This study highlights rising HPIV detection rates post-COVID-19 and underscores the need for continuous surveillance of HPIVs to inform public health strategies for future epidemic seasons.

Spatio-temporal variation and drivers of blue carbon sequestration in Hainan Island, China.

Blue carbon ecosystems, such as mangrove, seagrass bed and salt marsh, have attracted increasing attention due to their remarkable capacity for efficient carbon sequestration. However, the current threat posed by human activities to these ecosystems necessitates the characterization of their changes and identification of the primary driving factors in order to facilitate the gradual restoration of blue carbon ecosystems. In this study, we present an analysis of the spatio-temporal characteristics and primary influencing factors governing carbon sequestration in mangrove and seagrass beds located in Hainan Island. The findings revealed a 40% decline in carbon sequestration by mangroves from 1976 to 2017, while seagrass beds exhibited a 13% decrease in carbon sequestering between 2009 and 2016. The decline in carbon sequestration was primarily concentrated in Wenchang city, with aquaculture and population growth identified as the primary driving factors. Despite the implementation of measures aimed at reducing aquaculture in Hainan Island to promote blue carbon sequestration over the past two decades, the resulting recovery remains insufficient in achieving macro-level goals for carbon sequestration. This study emphasizes the necessity of safeguarding blue carbon ecosystems in Hainan Island by effectively mitigating anthropogenic disturbances.

Discovery of presumably introduced spiders, Oedignathascrobiculata Thorell, 1881 (Araneae, Liocranidae) and Boagriusqiong Lin & Li, 2022 (Araneae, Palpimanidae) on Chichi-jima Island, the Ogasawara Islands, Japan.

Background: The spider fauna of the Ogasawara Islands, oceanic islands located 1,000 km south of mainland Japan was comprehensively examined by the National Museum of Nature and Science in 2011, which revealed that approximately 70% of the spider fauna was composed of non-native species. Following the preceding study, however, only descriptions of several new species have been added and no major updates have been made for the overall spider fauna of the Islands. New information: The faunistic survey of spiders conducted on Chichi-jima Island, the largest island in the Ogasawara Islands in 2023 revealed the presence of two ground-dwelling spider species, Oedignathascrobiculata Thorell, 1881 (Araneae, Liocranidae) and Boagriusqiong Lin & Li, 2022 (Araneae, Palpimanidae) on the Island. This represents the first record of the two species from Japan, the first record of palpimaid spiders from Japan and the initial documentation of liocranid spiders in the Ogasawara Islands.

Parent material influences soil properties to shape bacterial community assembly processes, diversity, and enzyme-related functions.

Soil parent material is the second most influential factor in pedogenesis, influencing soil properties and microbial communities. Different assembly processes shape diverse functional microbial communities. The question remains unresolved regarding how these ecological assembly processes affect microbial communities and soil functionality within soils on different parent materials. We collected soil samples developed from typical parent materials, including basalt, granite, metamorphic rock, and marine sediments across soil profiles at depths of 0-20, 20-40, 40-80, and 80-100 cm, within rubber plantations on Hainan Island, China. We determined bacterial community characteristics, community assembly processes, and soil enzyme-related functions using 16S rRNA high-throughput sequencing and enzyme activity analyses. We found homogeneous selection, dispersal limitation, and drift processes were the dominant drivers of bacterial community assembly across soils on different parent materials. In soils on basalt, lower pH and higher moisture triggered a homogeneous selection-dominated assembly process, leading to a less diverse community but otherwise higher carbon and nitrogen cycling enzyme activities. As deterministic process decreased, bacterial community diversity increased with stochastic process. In soils on marine sediments, lower water, carbon, and nutrient content limited the dispersal of bacterial communities, resulting in higher community diversity and an increased capacity to utilize relative recalcitrant substrates by releasing more oxidases. The r-strategy Bacteroidetes and genera Sphingomonas, Bacillus, Vibrionimonas, Ochrobactrum positively correlated with enzyme-related function, whereas k-strategy Acidobacteria, Verrucomicrobia and genera Acidothermus, Burkholderia-Caballeronia-Paraburkholderia, HSB OF53-F07 showed negative correlations. Our study suggests that parent material could influence bacterial community assembly processes, diversity, and soil enzyme-related functions via soil properties.

A quick and effective trait-based protocol for selecting appropriate native plant species for the reforestation of degraded tropical mines.

Introduction: A critical issue in tropical forests is that anthropogenic deforestation (i.e., mining) degrades the integrity of its ecosystem. Reforestation with appropriate native plant species helps to alleviate these detrimental impacts. A protocol to select appropriate plant species for this purpose currently lacks efficacy and timeliness. Methods: We provided a trait-based protocol to quickly and effectively select native plant species for mining reforestation. A 0.2-km2 area of Baopoling (BPL) at Hainan Island, China, was used as a study site, which has been severely degraded by 20 years of limestone mining for cement production. First, we identified the tree species in nearby undisturbed tropical forests, followed by evaluating the similarities in functional traits of the most dominant one (target species) and 60 local candidate native plant species (candidate species) whose saplings can be purchased from a local market. Results and discussion: This dataset was used in our trait-based protocol, and only within 1 month, we successfully selected eight plant species which are very similar to target species from the 60 candidate species. We also quantified whether the eight selected plant species were indeed suitable for sustained reforestation by testing their effects on landscape and also their survival rate and recruitment ability after using them to perform reforestation in BPL from 2016 to 2023. Finally, these eight plant species are indeed suitable for reforestation due to their huge influences on a significant shift from originally degraded landscape (comprising only barren rocks) to a forest landscape totally and also their high survival rate (90%-97%) and ability for natural recruitment after 7 years' reforestation in BPL. Thus, we anticipate that this protocol would be integral to species selection during reforestation of tropical mining areas.