Chen X.,CAS Institute of Subtropical Agriculture |
Chen X.,Huanjiang Observation and Research Station for Karst Eco systems |
Chen X.,University of Chinese Academy of Sciences |
Su Y.,CAS Institute of Subtropical Agriculture |
And 6 more authors.
Plant and Soil | Year: 2013
Aims: This study was undertaken to investigate laccase-containing basidiomycete communities at the cDNA and DNA levels and to assess the influences of vegetation and soil types on the basidiomycete communities in forest soils. Materials and methods: Soil samples were collected from the upper soil layers of two typical subtropical forests (a broad-leaved forest developed in Karst limestone soil and an artificial coniferous forest with Pinus massoniana in red soil) in China. The basidiomycete communities were characterized by cloning and sequencing of the laccase genes at both the cDNA and DNA levels. Compositions of lignin monomers were determined by gas chromatography-mass spectrometry. Results: Most of the laccase genes obtained in this study were new, highlighting the research gap of this functional group. The trends of the basidiomycetous laccase gene diversity among the upper soil layers of the two forests were consistent between the cDNA and DNA levels. The Agaricales had high activity because they dominated all the tested soils. However, the total basidiomycete communities reflected at the cDNA and DNA levels were significantly different due to the presence of some quiescent basidiomycetous groups. Almost all of the lignin components were decomposed from the O to the A layers in the two forests, and laccases produced by Agaricales were likely responsible for the decomposition of guaiacyl monomers. Both vegetation and soil types had great influences on the active laccase-containing basidiomycete communities, primarily via the pH, C/N, and the contents of lignin monomers. Conclusions: The cDNA- and DNA-level approaches presented good consistency of diversities but different compositions of laccase-containing basidiomycete communities, thus emphasizing the importance of focusing on laccase genes at the cDNA level in future studies. It is the quality but not the quantity of SOM to determine the diversity and composition of the active laccase-containing basidiomycete communities. © 2012 Springer Science+Business Media B.V.
Tong X.,CAS Institute of Subtropical Agriculture |
Tong X.,Huanjiang Observation and Research Station for Karst Eco systems |
Tong X.,University of Chinese Academy of Sciences |
Wang K.,CAS Institute of Subtropical Agriculture |
And 10 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014
The annual dynamics and spatial variability of vegetation in northwest Guangxi were studied based on the SPOT NDVI datasets during 1999-2010. The response of vegetation to climate and topography was analyzed. The results showed that: (1) Vegetation had a large proportion of increasing trends in northwest Guangxi from 1999 to 2010. Partial correlation analysis between NDVI and climate parameters showed that climate had little effect on vegetation.(2) Elevation affected vegetation trend. It increased between 200 and 500 m, however, there were a small areas between 400 m and 500 m where vegetation decreased. Vegetation tended to be stable as the elevation increasing. (3) Vegetation recuperated on slopes between 6°and 15°, but decreased on slopes between 2°and 6°and above 25°. (4) The differences of vegetation restoration on aspects were not obvious. However, vegetation recovery trended to be decreasing as the aspect turning from shady to sunny slopes. Our study indicated that the implementation of environmental conservation policies and ecological construction had resulted in the improvement of vegetation in karst regions. However, there were some regions with vegetation degradation caused by human disturbance. In the further implementation of ecological restoration, the government should pay more attention to the sunny regions where the elevation between 400m and 500m and the steep slope that larger than 25°.
Liang Y.,CAS Institute of Subtropical Agriculture |
Liang Y.,University of Chinese Academy of Sciences |
Liang Y.,Huanjiang Observation and Research Station for Karst Eco systems |
He X.,CAS Institute of Subtropical Agriculture |
And 12 more authors.
Ecological Engineering | Year: 2015
Arbuscular mycorrhizal (AM) fungi are crucial for vegetation regeneration because they play an important role in plant establishment and growth. We investigated the relationships among AM fungal diversity, plant diversity, and soil properties during vegetation restoration in degraded karst ecosystems. Pyrosequencing approach was used to determine the genetic diversity and composition of AM fungal communities in four typical ecosystems of vegetation restoration (tussock (TK), shrub (SB), secondary forest (SF), and primary forest (PF)) in a karst region of southwest China. The diversity, richness, and evenness of plant species were evaluated through field surveys. Basic soil properties were measured. Plant species diversity and soil nutrient contents increased with vegetation restoration from tussock to primary forest, but the diversity of AM fungi followed the order of shrub ≈ secondary forest ≈ primary forest < tussock. The composition of AM fungi and plant communities differed significantly between ecosystems (p < 0.05). The richness of AM fungi was negatively correlated with both the plant diversity (the indices of plant Shannon-Wiener, evenness and richness) and soil properties (soil available phosphorus (AP), soil organic carbon (SOC) and pH) (p < 0.05). Redundancy analysis showed that the AM fungal communities closely linked to plant richness, soil organic carbon, soil available phosphorus and pH. These results suggest that the diversity and composition of AM fungi in karst region are influenced by plant communities and soil nutrient conditions. © 2015 Elsevier B.V.
Li L.,CAS Institute of Subtropical Agriculture |
Li L.,Huanjiang Observation and Research Station for Karst Eco systems |
Li L.,University of Chinese Academy of Sciences |
Xia Y.-H.,CAS Institute of Subtropical Agriculture |
And 17 more authors.
Journal of Mountain Science | Year: 2015
The conventional method which assumes the soil distribution is continuous was unsuitable for estimating soil organic carbon density (SOCD) in Karst areas because of its discontinuous soil distribution. The accurate estimation of SOCD in Karst areas is essential for carbon sequestration assessment in China. In this study, a modified method, which considers the vertical proportion of soil area in the profile when calculating the SOCD, was developed to estimate the SOCD in a typical Karst peak-cluster depression area in southwest China. In the modified method, ground-penetrating radar (GPR) technology was used to detect the distribution and thickness of soil. The accuracy of the method was confirmed through comparison with the data obtained using a validation method, in which the soil thickness was measured by excavation. In comparison with the conventional method and average-soil-depth method, the SOCD estimated using the GPR method showed the minimum relative error with respect to that obtained using the validation method. At a regional scale, the average SOCDs at depths of 0–20 cm and 0–100 cm, which were interpolated by ordinary kriging, were 1.49 (ranging from 0.03–5.65) and 2.26 (0.09–11.60) kgm−2based on GPR method in our study area (covering 393.6 hm2), respectively. Therefore, the modified method can be applied on the accurate estimation of SOCD in discontinuous soil areas such as Karst regions. © 2015, Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg.
Chen X.-B.,CAS Institute of Subtropical Agriculture |
Chen X.-B.,Huanjiang Observation and Research Station for Karst Eco systems |
Zheng H.,Guangxi Institute of Subtropical Crops |
Zhang W.,CAS Institute of Subtropical Agriculture |
And 9 more authors.
Journal of Mountain Science | Year: 2014
Land cover type is critical for soil organic carbon (SOC) stocks in territorial ecosystems. However, impacts of land cover on SOC stocks in a karst landscape are not fully understood due to discontinuous soil distribution. In this study, considering soil distribution, SOC content and density were investigated along positive successional stages (cropland, plantation, grassland, scrubland, secondary forest, and primary forest) to determine the effects of land cover type on SOC stocks in a subtropical karst area. The proportion of continuous soil on the ground surface under different land cover types ranged between 0.0% and 79.8%. As land cover types changed across the positive successional stages, SOC content in both the 0-20 cm and 20-50 cm soil layers increased significantly. SOC density (SOCD) within 0-100 cm soil depth ranged from 1.45 to 8.72 kg m-2, and increased from secondary forest to primary forest, plantation, grassland, scrubland, and cropland, due to discontinuous soil distribution. Discontinuous soil distribution had a negative effect on SOC stocks, highlighting the necessity for accurate determination of soil distribution in karst areas. Generally, ecological restoration had positive impacts on SOC accumulation in karst areas, but this is a slow process. In the short term, the conversion of cropland to grassland was found to be the most efficient way for SOC sequestration. © 2014 Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg.