Southern Guizhou Province Research Articles

Effects of wildfire on soil microbial communities in karst forest ecosystems of southern Guizhou Province, China.

Wildfires are unpredictable disturbances with profound effects on soil properties and microbial communities within forest ecosystems. However, knowledge of post-fire microbial communities in karst forests remains limited. In this study, microbial amplicon sequencing techniques were employed to investigate the impact of wildfires on the composition, diversity, function, and co-occurrence network of soil microbial communities in karst forest landscapes and to identify the key soil physicochemical factors affecting the post-fire microbial communities. The wildfire affected the fungal community to a greater extent than the bacterial community, with the former shifting from a dominance of Basidiomycota to Ascomycota at the phylum level, while the relative abundance of Actinobacteria increased significantly in the bacterial community. Moreover, the wildfire increased the α-diversity of the microbial community and changed the β-diversity. Network analysis indicated significant reductions in the complexity of microbial community networks and the hub microbiome in burned soils compared to those of unburned soils. Functional predictions indicated an increase in the highly abundant functional taxa of chemoheterotrophic and aerobic chemoheterotrophic bacteria, along with a significant rise in saprotrophic functional fungal taxa following the fire. In addition, soil organic matter, total nitrogen, total phosphorus, and soil water content emerged as key soil physicochemical factors affecting post-fire soil microbial communities in the karst forest. Overall, this study revealed the structural and functional characteristics of soil microbial communities and their key influencing factors after a fire in a karst forest, which will provide a valuable theoretical basis for ecosystem restoration after a wildfire.IMPORTANCEDespite the significant impacts of wildfires on forest ecosystems, most existing studies have largely focused on boreal and Mediterranean coniferous forest types, with limited research on the impacts of coniferous and broadleaf forest types in subtropical karst regions. This study reveals the effects of wildfires on soil microbial communities of coniferous and broadleaf forest types in a karst forest. The results of this study not only improve the understanding of the effects of wildfires on the composition, diversity, function, and network of soil microbial communities but also provide a meaningful theoretical basis for post-fire ecosystem restoration in the karst forest.

Depositional Environment and Ecological Response of Bioconstructions: A Case Study of Southern China (Guizhou Province) in Moscovian-Gzhelian.

From the late Carboniferous to the early Permian, multiple pulses of glaciation and deglaciation have been caused by the LPIA. The Pennsylvanian period experienced phases of recovery, proliferation, and decline, ultimately forming a reef system distinctly different from that of the Mississippian period. During the late Bashkirian to Moscovian, the metazoan reef experienced a limited resurgence, with reef predominantly formed by chaetetid developing in the United States, northern China, and Japan. During the Kasimovian to Gzhelian, the phylloid algal reef dominated the global reef systems. In the late Pennsylvanian, bioconstruction cases and paleoenvironmental proxies in southern Guizhou Province were studied to investigate the composition, recovery, and evolutionary processes of the bioconstructions as well as their response to environmental variations during this period. Several bioconstructions have been reported in the Lumazhai section of Houchang Town, Guizhou Province, southern China, from the Moscovian to the Gzhelian. The upper Carboniferous strata are well-preserved and continuously exposed. The continuous strata, abundant fossils, and diverse bioconstructions provide excellent research materials for exploring the mutual constraints between organisms and their environment. This study identified ten microfacies, whose vertical evolution indicated significant changes in the depositional environment related to relative sea-level fluctuations. Skeletal grains are widely present in these facies. Among them, foraminifera, algae, bryozoans, crinoids, and Tubiphytes are the most common and exhibit distinct distribution characteristics in various environments. Quantitative statistics, CCA and theoretical ecospace have been utilized to examine and interpret environmental impact factors. Quantitative analysis of their relative abundance and distribution patterns provides insights into the complex interactions between organisms and environmental factors. The relative abundances of different organisms and factors controlling their bioconstructions are influenced by relative sea-level changes. CCA analysis reveal that hydrodynamic conditions are the primary influencing factor. Variation trends in average tiering and motility reveal the characteristics of biological communities during environmental changes in phylloid algae and microbial bioconstructions. These bioconstructions are not directly correlated with changes in environmental factors, and the biological communities in phylloid algae mounds and biostromes exhibit similar organism compositions and ecological niches across different environments.

Description of a new Asian Leaf Litter Toad of the genus Leptobrachella Smith, 1925 (Anura, Megophryidae) from southern Guizhou Province, China.

The Asian leaf litter toads of the genus Leptobrachella Smith, 1925 (Anura, Megophryidae) inhabit the forest floor and rocky streams in hilly evergreen forests and are widely distributed from southern China, west to north-eastern India and Myanmar, through mainland Indochina to Peninsular Malaysia and the Island of Borneo. A new species of the Asian leaf litter toad genus Leptobrachella from Guizhou Province, China is described. Molecular phylogenetic analyses, based on mitochondrial 16S rRNA and COI genes and nuclear RAG1 gene sequences indicated that the new species is genetically divergent from its congeners. The new species could be distinguished from its congeners by a combination of the following characters: (1) body of medium size in males (SVL 31.9 - 32.9 mm); (2) distinct black spots present on flanks; (3) toes rudimentarily webbed, with wide lateral fringes; (4) skin on dorsum shagreened with fine tiny granules and short ridges; (5) heels overlapped when thighs are positioned at right angles to the body; (6) tibia-tarsal articulation reaching interior corner of the eye.A new species of the Asian leaf litter toad genus Leptobrachella from Guizhou Province, China is described. Molecular phylogenetic analyses, based on mitochondrial 16S rRNA and COI genes and nuclear RAG1 gene sequences indicated that the new species is genetically divergent from its congeners. The new species could be distinguished from its congeners by a combination of the following characters: (1) body of medium size in males (SVL 31.9 - 32.9 mm); (2) distinct black spots present on flanks; (3) toes rudimentarily webbed, with wide lateral fringes; (4) skin on dorsum shagreened with fine tiny granules and short ridges; (5) heels overlapped when thighs are positioned at right angles to the body; (6) tibia-tarsal articulation reaching interior corner of the eye.

Estimating Forest Aboveground Biomass Combining Pléiades Satellite Imagery and Field Inventory Data in the Peak–Cluster Karst Region of Southwestern China

The mountainous region of southwest China has the largest karst geomorphology in China and in the world. Quantifying the forest aboveground biomass in this karst region is of great significance for the investigation of carbon storage and carbon cycling in terrestrial ecosystems. In this study, the actual measured aboveground biomass was calculated based on the allometric functions of 106 quadrats from 2012 to 2015. A backpropagation artificial neural network (BPANN) inversion model was constructed by combining very high-resolution satellite imagery, field inventory data, and land use/land cover data to estimate the forest aboveground biomass in the Banzhai watershed, a typical peak–cluster karst basin in southern Guizhou Province. We used 70% of the actual measured aboveground biomass for training the BPANN model, 20% for accuracy verification, and 10% to prevent overtraining. The results show that the absolute root mean square error of the BPANN model was 11.80 t/ha, which accounted for 9.92% of the mean value of aboveground biomass. Based on the BPANN inversion model, the average value of the forests’ aboveground biomass was 135.63 t/ha. The results showed that our study presented a quick, easy, and relatively high-precision method for estimating forest aboveground biomass in the Banzhai watershed. This indicates that the Pléiades image-based BPANN model displayed satisfactory results for estimating the forests’ aboveground biomass in a typical peak–cluster karst basin. This method can be applied to the estimation of forest AGB in the karst mountainous areas of southwest China.

Upper Changhsingian to lower Anisian conodont biostratigraphy of the Datuguan section, Nanpanjiang Basin, South China

The Great Bank of Guizhou (GBG) of South China is an important area for the study of Lower Triassic conodont biostratigraphy, but few studies have concerned the clastic facies of this region. The Datuguan section in Luodian County, southern Guizhou Province, is a typical clastic ramp section, preserving a relatively complete conodont succession from the uppermost Permian to lower Middle Triassic. A total of nearly 4000 P1 elements were obtained from this section, and 48 conodont species belonging to 16 genera have been identified, including a new species, Gladigondolella luodianensis sp. nov. 12 conodont biozones have been recognized, namely, the Clarkina yini Zone, the C. meishanensis Zone, the Hindeodus postparvus Zone, the Novispathodus waageni Zone, the Discretella discreta Zone, the Nv. pingdingshanensis Zone, the Icriospathodus collinsoni Zone, the Triassospathodus homeri Zone, the Tr. symmetricus Zone, the Tr. triangularis Zone, the Tr. sosioensis Zone, and the Chiosella timorensis Zone in ascending order. These conodont zones improve the resolution of correlation with other sections in this region, as well as globally. Based on the conodont successions and correlation of lithology, the Permian–Triassic boundary (PTB) and the Griesbachian–Dienerian boundary (GDB) are temporarily placed at the middle of Bed 8, 7 m below the top of the Linghao Formation, and the top of Bed 12, 15 m above the bottom of the Luolou Formation, respectively. The Induan–Olenekian boundary (IOB), the Smithian–Spathian boundary (SSB), and the Olenekian–Anisian boundary (OAB) are drawn at Bed 15–1, Bed 27–1, and Bed 42–2, in terms of the first occurrences (FOs) of Nv. waageni sensu lato, Nv. pingdingshanensis, and Ch. timorensis sensu stricto respectively. The conodonts and ammonoids from the Datuguan section supplement the materials of the Guandao section, which is an important reference section for the definition of OAB. In addition, the distribution of segminiplanate conodonts from the platform margin to the basin center has been determined in the Nanpanjiang Basin, revealing that segminiplanates migrated to equatorial region four times and preferred a narrow mid-depth setting during relatively cooler periods of the Early Triassic, in addition to occupying the more oxygenated deep-water basin at other time.

Controlling of the Late Palaeozoic glaciation on reef evolution: A case study of a late Kasimovian coral reef in southern Guizhou, South China

A late Kasimovian (Pennsylvanian) coral reef is reported in the Yanbanzhai (YBZ) area, southern Guizhou Province, South China. The YBZ coral reef, with a thickness of approximately 5.5 m and a lateral exposure of nearly 50 m, is primarily composed of the colonial rugose coral Fomichevella. The fusulinids collected from the reef indicates a late Kasimovian age. Five microfacies types have been identified, including coated bioclastic grainstone, coral (Fomichevella) framestone, bioclastic wackestone, bioclastic grainstone, and peloidal grainstone. The vertical evolution of the microfacies in the YBZ coral reef indicates major sedimentary environmental changes associated with relative sea‐level changes. The growth of the reef‐builder Fomichevella was controlled by the transgression and regression. Deep water promoted the upward expansion of Fomichevella, while shallow water inhibited its growth. Published records of atmospheric pCO2 estimation and sea‐surface temperatures, combined with geochemical proxies, confirm a warm climatic period during the late Kasimovian. This is an interglacial period conducive to the growth of the coral reef. Sea‐level and climate changes associated with the Late Palaeozoic ice age (LPIA) are interpreted as significant controls of the development of the YBZ coral reef. This research of the YBZ coral reef in South China provides practical palaeobiological evidence for global sea‐level rising during the late Kasimovian period caused by the high‐latitude Gondwana delaciation.

Geological evaluation and gas bearing analysis for shale reservoir in Ziyun-Luodian typical area of southern Guizhou province, China

The Ziyun-Luodian area of southern Guizhou province in China is chosen as the research area and the Dawuba formation in Carboniferous system is the target stratum in this paper. Combined with laboratory experiments and mathematical analyses, geological evaluations on organic geochemistry, physical property of the reservoir, and gas bearing feature are all studied, and geological controls on gas occurrence are then analyzed. The following conclusions are achieved. The organic type is mainly II2 or III. TOC is generally in a range of 1%–3%, and Ro,max ranges from 1.7% to 4.4%, with an average value of 2.4%. Mineral compositions are mainly clay and quartz, with a few calcite and dolomite. The Specific surface area ranges from 6.6 to 29.8 m2/g, with an average value of 15.2 m2/g, and the pore volume varies from 0.012 to 0.046 cm3/g, with an average value of about 0.02 cm3/g. There is a strongly and positively linear relationship between specific surface area and pore volume. The porosity is mostly in the range of 1%–3%, with an average value of 1.8%. Most of permeability is below 0.01 mD, with an average value of about 0.004 mD. There is an exponential and positive relationship between porosity and permeability. The gas content is generally below 2.0 m3/t. There are three obvious correlations for gas content versus buried depth ranges of 500–700 m, 700–1,000 m, and 2,700–3,000 m. TOC influences gas content in a linear mode, and Ro,max influences gas content positively. The gas content has a positive relationship with clay mineral and a negative relationship with sapropelic percentage. The porosity and permeability are both positively correlated with gas content. The pore volume has a positive trend with gas content, and the specific surface area has a positively and strongly linear relationship with gas content.

A new toad species of the genus Brachytarsophrys Tian & Hu, 1983 (Anura, Megophryidae) from Guizhou Province, China.

BackgroundThe toads of the genus Brachytarsophrys Tian & Hu, 1983 are distributed in southern China, Myanmar, Vietnam, Laos and northern Thailand. Seven species of the genus have been recognised, of which five of them are known from China so far.New informationBrachytarsophrysqiannanensis sp. nov., a new species of the short-legged toad genus is here described from southern Guizhou Province, China. Diagnostic characters of the new species are illustrated and comparisons with its congeners are provided. Its validity is also affirmed by its distinct mitochondrial gene sequence divergence with all congeners and its monophyly recovered in the mitochondrial gene-based phylogenetic analyses.

Spatiotemporal Dynamic Analysis of A-Level Scenic Spots in Guizhou Province, China

A-level scenic spots are a unique evaluation form of tourist attractions in China, which have an important impact on regional tourism development. Guizhou is a key tourist province in China. In recent years, the number of A-level scenic spots in Guizhou Province has been increasing, and the regional tourist economy has improved rapidly. The spatial distribution evolution characteristics and influencing factors of A-level scenic spots in Guizhou Province from 2005 to 2019 were measured using spatial data analysis methods, trend analysis methods, and geographical detector methods. The results elaborated that the number of A-level scenic spots in all counties of Guizhou Province increased, while in the south it developed slowly. From 2005 to 2019, the spatial distribution in A-level scenic spots were characterized by spatial agglomeration. The spatial distribution equilibrium degree of scenic spots in nine cities in Guizhou Province was gradually developed to reach the “relatively average” level. By 2019, the kernel density distribution of A-level scenic spots had formed the “two-axis, multi-core” layout. One axis was located in the north central part of Guizhou Province, and the other axis ran across the central part. The multi-core areas were mainly located in Nanming District, Yunyan District, Honghuagang District, and Xixiu District. From 2005 to 2007, the standard deviation ellipses of the scenic spots distribution changed greatly in direction and size. After 2007, the long-axis direction of the ellipses gradually formed a southwest to northeast direction. We chose elevation, population density, river density, road network density, tourism income, and GDP as factors, to discuss the spatiotemporal evolution of the scenic spots’ distribution with coupling and attribution analysis. It was found that the river, population distribution, road network density, and the A-level scenic spots’ distribution had a relatively high coupling phenomenon. Highway network density and tourist income have a higher influence on A-level tourist resorts distribution. Finally, on account of the spatiotemporal pattern characteristics of A-level scenic spots in Guizhou Province and the detection results of influencing factors, we put forward suggestions to strengthen the development of scenic spots in southern Guizhou Province and upgrade the development model of “point-axis network surface” to the current “two-axis multi-core” pattern of tourism development. This study can explain the current situation of the spatial development of tourist attractions in Guizhou Province, formulate a regulation mechanism of tourism development, and provide a reference for decision-making to boost the high-quality development of the tourist industry.

An Improved Segmentation Method for Automatic Mapping of Cone Karst from Remote Sensing Data Based on DeepLab V3+ Model

The South China Karst, a United Nations Educational, Scientific and Cultural Organization (UNESCO) natural heritage site, is one of the world’s most spectacular examples of humid tropical to subtropical karst landscapes. The Libo cone karst in the southern Guizhou Province is considered as the world reference site for these types of karst, forming a distinctive and beautiful landscape. Geomorphic information and spatial distribution of cone karst is essential for conservation and management for Libo heritage site. In this study, a deep learning (DL) method based on DeepLab V3+ network was proposed to document the cone karst landscape in Libo by multi-source data, including optical remote sensing images and digital elevation model (DEM) data. The training samples were generated by using Landsat remote sensing images and their combination with satellite derived DEM data. Each group of training dataset contains 898 samples. The input module of DeepLab V3+ network was improved to accept four-channel input data, i.e., combination of Landsat RGB images and DEM data. Our results suggest that the mean intersection over union (MIoU) using the four-channel data as training samples by a new DL-based pixel-level image segmentation approach is the highest, which can reach 95.5%. The proposed method can accomplish automatic extraction of cone karst landscape by self-learning of deep neural network, and therefore it can also provide a powerful and automatic tool for documenting other type of geological landscapes worldwide.

Three new species of the aphaenopsian trechine genus Pilosaphaenops Deuve & Tian, 2008 from South China Karst (Coleoptera: Carabidae: Trechinae)

Summary Three new trechine species of the genus Pilosaphaenops Deuve & Tian, 2008, P. qianzhii n. sp. from cave Lubian Dong in Pingtang County, southern Guizhou Province, P. mengzhenae n. sp. and P. weiguofui n. sp. from cave Xia Dong in Nandan County, and cave Shenlong Gong in Huanjiang County respectively, northern Guangxi Zhuang Autonomous Region, are described and illustrated. A key to all known species of this genus is also provided. http://www.zoobank.org/urn:lsid:zoobank.org:pub:170C467F-5421-49AD-B1B1-091D8BD58B88

A new anophthalmic trechine genus and two new species from southern Guizhou, China (Coleoptera: Carabidae: Trechini).

A new genus and two new species of cavernicolous trechine beetles are reported from southern Guizhou Province, Southwest China: Miaotrechus mahua n. gen., n. sp. from the cave Miaoting, Getuhe cave system, Ziyun Miao Buyi Zizhi Xian (Autonomous County), Anshun Shi; M. heweii n. sp. from the cave Jingua Dong, danzhai County, Qiandongnan Miao Dong Zizhizhou (Autonomous Prefecture). Miaotrechus might be related to the genus Guizhaphaenops Vigna Taglianti, 1997, but it is an Anophthalmus-like, whereas Guizhaphaenops species are semi-aphaenopsian.

Diabase Sills in the Outer Zone of the Emeishan Large Igneous Province, Southwest China: Petrogenesis and Tectonic Implications

Compositionally and texturally zoned diabase dykes and sills occur in the outer zone of the Emeishan large igneous province (ELIP) in the southern Guizhou Province, Southwest China. Based on the detailed petrology, whole rock geochemistry, zircon U-Pb geochronology and Hf isotopes and clinopyroxene mineral compositions studies, we investigate a representative diabase sill in the Luodian region with a view to understanding its petrogenesis and tectonic implications. Formed as composite zoned sub-volcanic intrusion, the diabase sill is characterized by gabbros and diabases in the inner zone and amygdaloidal diabases sporadically in the chilled zone within the upper sill margin. The diabasic and gabbroic rocks are composed of quartz-free and quartz-bearing groups. The quartz-free group rocks have low SiO2 (45.7 wt.%-49.5 wt.%), moderate MgO (5.66 wt.%-7.88 wt.%), high TiO2 (2.54 wt.%-3.65 wt.%), and Ti/Y values (536-747), corresponding to high-Ti type rocks. The quartz-bearing group rocks have higher SiO2 (49.8 wt.%-51.7 wt.%) and lower MgO (4.23 wt.%-4.74 wt.%), higher TiO2 (3.16 wt.%-3.63 wt.%), but lower Ti/Y values (399-419) than the quartz-free group ones, and thus belong to the low-Ti type. Both groups of rocks are enriched in LREE and LILE with negative Nb-Ta anomalies, and show broad tholeiitic affinity. The precursor magma of the high-Ti rocks might have originated from a source composed of mantle plume and subcontinental lithosphere mantle components, with minor crustal contamination during ascending. The magma of the low-Ti rocks was produced by mingling of the high-Ti diabasic rocks with minor injected intermediate-acidic magma plugs or blebs, suggesting magma mingling as one of the effective ways to change the high-Ti to low-Ti rocks of the ELIP. The diabasic sill underwent a rapid cooling event probably in response to a rapid tectonic uplift event, which probably occurred in the waning stage of ELIP during transition between the Middle and Late Permian after the domal uplift induced by the mantle-plume or in the Late Jurassic.

First Report of Lasiodiplodia theobromae Causing Leaf Spot on Tea Plant in Guizhou Province of China

Tea plant (Camellia sinensis) has been widely grown in Guizhou Province in China in recent years. A survey that was conducted from May to October 2016, in the main tea production fields in Huishui County (26.22 °N, 107.08 °E), southern Guizhou Province, revealed spots on tea leaves that were initially chlorotic and then brown, necrotic, and surrounded by slightly chlorotic halos. Spots gradually enlarged, formed larger irregular shapes, and covered the entire width of the leaves. The color of the lesion’s center changed to dark brown or black. Tea leaves with extensive lesions gradually dried and dropped off the plant. Disease incidence of leaves was estimated at 30 to 45%, depending on the field. Disease severity on a plant basis was estimated to be 32 to 38%. To identify the etiology of this disease, samples taken from the lesion margins were surface sterilized with 75% ethanol followed by 0.5% sodium hypochlorite for 30 s, rinsed with sterile water three times, and plated on potato dextrose agar (PDA). The plates were incubated at 25°C in darkness for 3 to 5 days, and then hyphal tips from the margin of a growing colony were successively transferred to fresh PDA plates to study their morphological and molecular characteristics. The fungal colonies were initially white, with sparse aerial mycelia 2 days after the inoculation, and they later turned gray, with woolly aerial mycelia 7 days after the inoculation. Globose to subglobose pycnidia were formed on 2- and 3-week-old cultures. The immature conidia were initially ovoid, hyaline, and aseptate, 25.83 (21 to 29) × 14.59 (12 to 15) μm (n = 50) single spores. Mature conidia became dark brown with striated cell walls and had a median septum. These observed morphological features are in accordance with those previously described for Lasiodiplodia theobromae (Pat.) Griffon & Maubl (Alves et al. 2008). The internal transcribed spacer (ITS1-5.8S-ITS2) and part of the translation elongation factor 1-alpha genes of the isolates were further amplified following the methods described in Alves et al. (2008) and then sequenced and deposited in GenBank. BLAST algorithm-based analyses showed 99 and 100% identities between six isolates (MH151161 and MH151160, etc.) and L. theobromae (KX270362.1 and KU886956.1, respectively). To fulfill Koch’s postulates, PDA plugs with actively growing mycelia from three isolates were placed on wounded tea leaves using a sterile needle or a sterile scalpel, covered with wet cotton, and kept under 80% relative humidity until symptom development (n = 10 for each isolate). The light brown leaf spots formed 1 to 2 days after inoculation and then gradually enlarged with the color becoming black in the center of the lesion. The spots resulted in a rapid necrosis and withered the entire leaf, as well as the top tender bud and fresh leaf, whereas the control leaves inoculated with PDA plugs without mycelia showed no symptoms. L. theobromae was consistently reisolated from inoculated leaves. L. theobromae is a plurivorous pathogen found worldwide, and it is transmitted in many ways. It has been previously reported to cause root disease in tea bushes after pruning (Petch 1923; Punithalingam 1976), foliar diseases on tea oil Camellia (Zhu et al. 2014) and on Parthenium (Kumar and Singh 2000), but not to cause disease on tea leaves in China. To our knowledge, this is the first report of L. theobromae causing leaf spot on tea plants in China. This identification will help producers in Guizhou Province seek and adopt appropriate field management measures to prevent and control this disease.

Elemental Geochemical Evidence for Depositional Conditions and Organic Matter Enrichment of Black Rock Series Strata in an Inter-Platform Basin: The Lower Carboniferous Datang Formation, Southern Guizhou, Southwest China

The Datang Formation black rock series deposited in an inter-platform basin are considered to be one of the main source rocks in Southwest China. However, their depositional conditions and organic matter enrichment in such a setting are not well understood. In this study, geochemical characteristics of total organic carbon (TOC), major, trace and rare earth elements (REEs) of thirty black rock series samples from a newly-cut roadside outcrop (Zhenning section) in Southern Guizhou, Southwest China are systematically investigated to examine provenance, paleoredox conditions, paleoclimate, paleoproductivity and sedimentary rate, and further to explore their influence on organic matter enrichment. Results show that TOC contents of the investigated samples range from 0.90% to 2.83%, with an average of 1.45%, with TOC variations being in accord with the stratigraphic cyclicity. These data also indicate that the target black rock series were deposited in a combination of continental island arc and active continental margin tectonic setting that exhibited moderate weathering, oxic/dysoxic oxygen levels, hot and arid to semiarid climate, and a higher sedimentary rate. Multiple paleoredox indicators (e.g., Ni/Co, V/Cr, U/Th and V/(V + Ni) ratios), together with slightly negative Ce anomalies and EFU-EFMo covariation, totally suggest an oxic/dysoxic water environment, which is usually considered unfavorable for organic matter preservation. Average (La/Yb)N ratios (1.41) reflect a higher sedimentary rate, resulting in shortening the exposure time of organic matter in the degradation region of aerobic bacteria under oxic/dysoxic conditions. Of the three factors that could affect organic matter enrichment, including paleoproductivity, paleoredox conditions and sedimentary rate, the relatively high paleoproductivity indicated by the relatively high TOC contents appears to be the dominant factor. In contrast, the other two factors, i.e., paleoredox conditions and the rate of sedimentation play relatively less significant roles. Based on these factors, an enrichment model of organic matter for the black rock series in Southern Guizhou Depression is established. These findings also contribute to constraining the sedimentary environment in such a setting and further deepen our understanding of the potential shale gas resources of the Southern Guizhou Province.

Contribution to the knowledge of the aphaenopsian genus Sinaphaenops Uéno et Wang, 1991 (Coleoptera: Carabidae: Trechini).

A revision of the genus Sinaphaenops Uéno et Wang, 1991 is provided, with a modified key to species. Two new species are described and illustrated in southern Guizhou Province: S. yaolinensis sp. n. (from a limestone cave called Yaolin Rongdong, Du'yun Shi) and S. banshanicus sp. n. (from Cave Banshan Dong, Guiding County). Male genital characteristics of S. mochongensis Tian et Huang, 2014 are reported for the first time. New records for other three Sinaphaenops species are given. In addition, an identification key to subgenera and species of Sinaphaenops is provided.

喀斯特天然林植物多样性指数和土壤理化指标的相关性

PDF HTML阅读 XML下载 导出引用 引用提醒 喀斯特天然林植物多样性指数和土壤理化指标的相关性 DOI: 10.5846/stxb201403220514 作者: 作者单位: 贵州省林业科学研究院,贵州省林业科学研究院;贵州大学,贵州省林业科学研究院,贵州大学;贵州省林业科学研究院,贵州省林业科学研究院,贵州省林业科学研究院,贵州省林业科学研究院,贵州省林业科学研究院,贵州大学;贵州省林业科学研究院 作者简介: 通讯作者: 中图分类号: 基金项目: 林业公益性行业科研专项(201104002);贵州省科技厅项目(黔省专合字TZJF2008-17,2009-2083,2008-73,黔科合字2007-1021,2010-05) Correlation on plant diversity indices and soil physical and chemical indicators of karst natural forest, Southern Guizhou Province, China Author: Affiliation: Guizhou Provincial Academy of Forestry,,,,,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:植物多样性的土壤生态系统功能是喀斯特生态学研究的热点之一。在贵州省茂兰国家级自然保护区不同功能区(干扰等级)内采用野外样地调查和实验室分析相结合的方法,分析了41个喀斯特森林样地的植物多样性指数和土壤理化指标值的变化规律与相关性。结果表明:(1)依据乔木层物种重要值聚类法划分的5个喀斯特森林类型包括小叶栾树-青冈栎林、香叶树-枫香林、香椿-香叶树林、灯台-小花梾木林和檵木-马尾松林,由核心区、缓冲区、实验区至外缘区,乔木层植物多样性指数、林地岩石裸露率、土壤蓄水量、肥力及养分指标呈降低趋势。(2)因子分析表明不同层片植物多样性和不同土层土壤理化因子的相关趋势性各异。相关显著的因子对数量率呈乔木 > 灌木 > 草本的趋势,乔木植物多样性因子起主导作用。(3)喀斯特森林乔木层植物多样性指数和土壤理化指标的相关性分3种类型。直线型是植物多样性指数和土壤理化指标值相关性中较普遍的一类,相应指标对数量率为39.84%;曲线型是植物多样性指数和土壤理化指标值相关性中机理较复杂的一类,相应指标对数量率为46.10%,其中植物多样性指数有拐点值无生态意义的指标对数量率为11.72%,有拐点值有生态意义且呈先降后升、或先升后降趋势的指标对数量率分别为17.19%;无关型是植物多样性指数和土壤理化指标值相关性不显著,相应指标对数量率为54.69%。(4)喀斯特地区水土资源管理为目标的营林措施中,天然林乔木层植物多样性指数对土壤物理、肥力和养分指标响应的拐点值可成为人工造林中物种数量与株数比例选择的参考依据之一。 Abstract:Soil ecosystem function and plant diversity is receiving much attention in karst ecological studies. Changes and correlation laws in plant diversity indices and soil physical and chemical indicators of 41 karst forest plots were analyzed on different functional areas in the Maolan National Nature Reserve of southern Guizhou Province, China. This research adopted the combination method of wild field plot investigation and laboratory analysis. Results show:(1) The importance values of the arbor species clustering method resulted in five karst forest types:Koelreuteria minor-Cyclobalanopsis glauca forest, Lindera communis-Liquidambar formosana forest, Toona sinensis-Lindera communis forest, Cornus controversa-Cornus parviflora forest and Loropetalum chinense-Pinus massoniana forest. The arbor plant diversity indices, bare rock coverage, soil water storage indicators, soil fertility indicators and nutrient indicators showed a decreasing trend from the core area, to the buffer area, to the experimental area and to the outer area. The Margalef index, Simpson index, Shannon-Wiener index and Pielou index of the arbor and herb layer species showed a significant difference between some forest types. However, the diversity indices differences of the shrub layer were not significant. Significant differences of some indicators between the different forest types confirmed the influence of human disturbance to the karst forest in the natural recovery process. (2) Factor analysis revealed different correlation trends between the plant diversity factors of different layers, and the physical and chemical factors of different soil horizons. The analysis conformed to the general regularity of plant growth in the development of the arbor, shrub and herb layer and the co-evolution between the vegetation and soil system of karst forest in the natural recovery process. The number rate of significant factor-pairs of the soil physical and chemical indicators related to the arbor, shrub and herb plant diversity indices were 36.38%, 27.27% and 18.19%, respectively. The arbor plant diversity factor had the strongest relationship with the soil physical and chemical indicators. (3) The significant correlations between the arbor plant diversity indices and the soil physical and chemical indicators were divided into three types:i) Linear correlation is a general relationship between the plant diversity indices and soil physical and chemical indicators; 39.84% of the indicator-pairs were in this category, where the plant diversity indices increased to raise or lower the soil physical and chemical indicators accordingly. ii) Curve correlation is a complex relationship between the plant diversity indices and soil physical and chemical indicators; 46.10% of indicator-pairs are accounted for in this way. Inflection point values of the plant diversity indices without ecological meaning accounted for 11.72% where the relationship could be explained using straight lines or other models. The ecological inflection points of the plant diversity indices, which periodically impacted on soil physical and chemical indicators between the upwards and downwards trends of the quadratic curves, accounted for 17.19% of the indicator-pairs. The values of these plant diversity indices can be adjusted on the basis of the soil management goal in forest planting. iii) No significant correlation means the plant diversity indices are independent of the soil physical and chemical indicators, and planting measures for plant diversity indices cannot effectively change the soil physical and chemical indicators; 54.69% of indicator-pairs corresponded to this model. The different response modes aid the interpretation of ecosystem function through the plant diversity hypothesis. (4) Inflection points are the top values of the upwards and downwards trends in the quadratic curve response of arbor plant diversity indices to soil physical and chemical indicators. They are in index values of Margalef for 0.71-2.70 and 4.80-9.70, Simpson for 0.57-0.66 and 0.72-0.86, Pielou for 0.50-0.76 and 0.83-0.95 and Shannon-Wiener for 1.35-1.43 and 2.57-3.47, respectively. These values are used for one of the selection references of species and number proportions in artificial forestation. 参考文献 相似文献 引证文献

Vegetation in karst terrain of southwestern China allocates more biomass to roots

Abstract. In mountainous areas of southwestern China, especially Guizhou province, continuous, broadly distributed karst landscapes with harsh and fragile habitats often lead to land degradation. Research indicates that vegetation located in karst terrains has low aboveground biomass and land degradation that reduces vegetation biomass, but belowground biomass measurements are rarely reported. Using the soil pit method, we investigated the root biomass of karst vegetation in five land cover types: grassland, grass–scrub tussock, thorn–scrub shrubland, scrub–tree forest, and mixed evergreen and deciduous forest in Maolan, southern Guizhou province, growing in two different soil-rich and rock-dominated habitats. The results show that roots in karst vegetation, especially the coarse roots, and roots in rocky habitats are mostly distributed in the topsoil layers (89 % on the surface up to 20 cm depth). The total root biomass in all habitats of all vegetation degradation periods is 18.77 Mg ha−1, in which roots in rocky habitat have higher biomass than in earthy habitat, and coarse root biomass is larger than medium and fine root biomass. The root biomass of mixed evergreen and deciduous forest in karst habitat (35.83 Mg ha−1) is not greater than that of most typical, non-karst evergreen broad-leaved forests in subtropical regions of China, but the ratio of root to aboveground biomass in karst forest (0.37) is significantly greater than the mean ratio (0.26 ± 0.07) of subtropical evergreen forests. Vegetation restoration in degraded karst terrain will significantly increase the belowground carbon stock, forming a potential regional carbon sink.

Early Triassic conodonts of Jiarong, Nanpanjiang Basin, southern Guizhou Province, South China

Jiarong (Huishui County, Guizhou Province, South China) is a key locality for the study of the Early Triassic recovery after the end-Permian mass extinction. The size reduction of conodonts at the Smithian/Spathian transition was first documented in Jiarong, and it is also a locality that contributes to the documentation of the Early Triassic paleo-seawater temperatures. In the Jiarong sections, thirteen conodont zones were identified for the Early Triassic; in ascending order, they are Hindeodus parvus Zone, Hindeodus sosioensis Zone, Clarkina krystyni Zone, Neoclarkina discreta Zone, Neospathodus cristagalli–Eurygnathodus costatus assemblage zone, Novispathodus waageni eowaageni Zone, Novispathodus waageni waageni Zone, Discretella discreta Zone, Pachycladina–Parachirognathus assemblage zone, Novispathodus pingdingshanensis Zone, Icriospathodus collinsoni Zone, Triassospathodus homeri Zone, Triassospathodus triangularis Zone. These conodont zones in the Jiarong sections improve the global correlation of Early Triassic sections and also provide better regional age constraints in an area that is important for studies of recovery from the extinction. Based on the first appearance of Nv. waageni eowaageni, the Induan/Olenekian boundary is recognized at 3.6m above the base of the Jiarong III Section. The dominance of blade-shaped (segminate) conodonts was replaced by gondola-shaped (segminiplanate) conodonts twice; the first time was in the late Griesbachian, and the second time was in the early Spathian. The dominance of segminiplanate conodonts probably indicates that the deeper seawater environment became more oxygenated during the late Griesbachian and early Spathian for short time intervals, as it is believed that the Griesbachian segminiplanate conodonts favored deeper oxygenated water habitats. A new genus, Spathogondolella gen. nov., and a new species, Spathogondolella jiarongensis sp. nov., have been recognized.

Palaeoecology of microconchids from microbialites near the Permian–Triassic boundary in South China

Abundant isolated specimens of microconchid tubes have been extracted from a microbialite deposit near the Permian–Triassic boundary (PTB) in the Dajiang section, southern Guizhou Province, South China. They are assignable to Microconchus aff. utahensis, M. aff. aberrans and Helicoconchus aff. elongatus, all of which possess micro-lamellar tube walls. Quantitative analysis of bulk samples indicates that most microconchids occur in the upper part of the PTB microbialite deposit and show substrate selectivity for bioclastic grainstone–packstones. In contrast, very few microconchids were found in the rocks bearing well-developed microbialite structures. Both stratigraphical and substrate preferences indicate proliferation of microconchids coincided with an ebb of microbialite development. Microconchids therefore only proliferated in local niches in which microbial activities were not very active within the PTB microbialite ecosystem. The presence of abundant microconchids further strengthens the impression that PTB microbialite metazoans are much more diverse than previously thought. The end-Permian mass extinction is calibrated to the base of microbialite deposit in South China. Thus, abundant microbialite metazoans, such as ostracods, lingulid brachiopods, microgastropods and microconchids, together with the considerable, temporarily surviving faunas reported from non-microbialite PTB sections in South China, indicate that metazoans diversified immediately after the first episode of the end-Permian mass extinction, supporting the scenario that marine ecosystems underwent episodic collapses during the devastating biocrisis over the Permian–Triassic transition.