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Xu C.,CAS Institute of Geology and Geophysics | Xu C.,Humanity | Ge J.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | Ge J.,Chinese Academy of Sciences | And 5 more authors.
Journal of Geophysical Research: Atmospheres | Year: 2016

In this study, we investigated the interannual and intraannual variabilities in the oxygen isotope composition (δ18O) preserved in the tree ring cellulose of Pinus taiwanensis in the lower reaches of the Yangtze River, southeast China, to explore its potential utility for precipitation reconstruction over the period of 1855-2013. Intraannual variations of tree ring cellulose δ18O show distinct annual cycles that are characterized by δ18O maxima in the early growth near the ring boundary and δ18O minima in the middle and late portions of the ring. Seasonal patterns of tree ring δ18O were influenced by August-October typhoons. The tree ring cellulose δ18O was measured in both young and old trees to test for the juvenile effect. The results revealed no significant differences in the mean values and long-term trends in δ18O in the old and young trees. A response analysis indicated that tree ring δ18O correlated significantly with precipitation and relative humidity between May and October, and the δ18O chronology accounted for 37.4% of the actual variation in the May-October precipitation between 1951 and 2013. The extremely dry and wet years revealed by the tree ring δ18O-based reconstructed precipitation also corresponded to actual local drought and flood events from the documentary records. Reconstructed precipitation showed significant relationship with central tropical Pacific sea surface temperature, which indicated that El Niño-Southern Oscillation (ENSO) exerted influences on May-October precipitation in the lower reaches of the Yangtze River. In addition, the relationship between ENSO and precipitation weakened between 1920 and 1940, and low variance of ENSO from 1920 to 1940 may result in the damped ENSO's influences on precipitation in southeast China. ©2016. American Geophysical Union. All Rights Reserved.


Chen C.,Fujian Normal University | Chen C.,Key Laboratory of Humid Subtropical Eco geographical Process
Wetland Science | Year: 2014

Establishing nature reserve is one of the most efficient approaches of conservation to biodiversity and restoration to ecological service functions, decision-maker of the nature reserves, and community residents and researchers commonly concerned with how to effectively manage the nature reserve in this paper. Some methods such as document research, questionnaire survey and mathematical statistics were used to analysis management stake-holder of Zhangjiangkou Mangrove Forest National Nature Reserve in Fujian province; the public administration of the nature reserve from ecological value, economic value and social value was discussed in the paper. The results showed that the stakeholders in the management of the nature reserve were classified into 3 types, including definitive, expectant and latent types, the definitive stakeholders in the management of the nature reserve were local government, local community residents, non-government organizations, enterprises and tour companies, which had an important role in the management of the nature reserve. The local government concerned about the ecological value, the local community residents concerned about the economic value, the non-government organizations concerned about the social value, the enterprises and tour companies concerned about the economic value; the mode of reasonable public administration of the nature reserve was constructed.


Xu C.,Humanity | Xu C.,Key Laboratory of Humid Subtropical Eco geographical Process | Zheng H.,Fujian Normal University | Zheng H.,Key Laboratory of Humid Subtropical Eco geographical Process | And 2 more authors.
Journal of Geophysical Research: Atmospheres | Year: 2013

A tree ring cellulose oxygen isotope (δ18O) chronology for the period 1870-2011 was established using samples from four Fokienia hodginsii trees with the aim of exploring the potential to use tree ring δ18O records to reconstruct climatic variations in Fujian, a subtropical region of southeast China. We believe that this is the first tree ring δ18O chronology from this area. Response analysis revealed that tree ring δ18O is significantly correlated with precipitation between April and September, relative humidity between August and October, and the Palmer drought severity index between April and October. Our δ18O chronology accounts for 37.4% (24.6%) of actual variation in precipitation between April and September during the period from 1951 to 2011 (1901 to 2011). Spatial correlation analysis revealed that tree ring cellulose δ18O is a suitable proxy for reconstructing April-September precipitation in Fujian, as well as in parts of Guangdong and Jiangxi, southeast China. In addition, significant correlations between δ18O chronology and the Indian summer monsoon index show that large-scale atmosphere circulation also influences tree ring δ18O. Comparisons between the tropical Pacific sea surface temperature (SST) and tree ring δ18O, during the period from 1895 to 2009, indicate that the tropical Pacific SST is positively correlated with tree ring δ18O in the study region over the last 110 years, except between 1920 and 1960. Reduced El Niño-Southern Oscillation (ENSO) variance from 1920 to 1960 may result in collapsed relationship between tree ring δ18O in Fujian and tropical Pacific SST. Key Points Tree ring oxygen isotope is a promising proxy to reconstruct rainfall ENSO influence on southeast China is low during 1920-1960 Indian summer monsoon affect tree ring oxygen isotope in southeast China ©2013. American Geophysical Union. All Rights Reserved.


Ma H.-L.,Key Laboratory of Humid Subtropical Eco geographical Process | Ma H.-L.,Fujian Normal University | Zhu J.-G.,CAS Nanjing Institute of Soil Science | Xie Z.-B.,CAS Nanjing Institute of Soil Science | And 2 more authors.
Communications in Computer and Information Science | Year: 2013

In order to investigate the role of residue and root carbon inputs in soil carbon changes due to elevated CO2, soil sample weighted 500 g collected from field under elevated CO2 and ambient CO2 condition, respectively, were incubation for one year with addition of straw and chemical matters, and then examined the different aggregates fraction and aggregated-associated carbon in soil. The results showed that the soil carbon for macro- (>250 μm) and micro-aggregates (250-53 μm) increased by 8.8-73.1% due to the addition of straw and by 11.2-111.7% (p<0.05) due to the exudates. Conversely, soil carbon in the clay and silt-sized particles (<53 μm) was decreased by 12.3-22.1% (p<0.05) by glucose and decreased even further with the addition of straw, whereas it was increased only by 5.8-11.8% with phenol and organic acid. These results could help to understand deeply the effects of elevated CO2 on the dynamics of both soil aggregates and carbon in a field due to variations in the crop straws and root exudates forms. © Springer-Verlag Berlin Heidelberg 2013.


Li X.,Key Laboratory of Humid Subtropical Eco geographical Process | Li X.,Fujian Normal University | Yang Y.,Key Laboratory of Humid Subtropical Eco geographical Process | Yang Y.,Fujian Normal University | And 8 more authors.
ISWREP 2011 - Proceedings of 2011 International Symposium on Water Resource and Environmental Protection | Year: 2011

Given lawns cultivation are expanding rapidly with urbanization in China and plays an important role in regional carbon cycle, but little is know about its carbon cycling. In this study, soil CO2 efflux (soil respiration, Rs) was partitioned into root (Rr) and microbial (R h) components by using a deep-collar insertion method in Zoysia matrella lawns. Results indicated that both Rr and Rh presented pronounced seasonal patterns and were highly dependent on soil temperature and biomass. The annual Rr and Rh were 435 gC/(m2·y) and 1249 gC/(m2·y), respectively, thus the annual value of RC was 25.8%. These results suggest that the R s of lawns in subtropical China is mainly microbe-derived. © 2011 IEEE.


PubMed | Key Laboratory of Humid Subtropical Eco geographical Process, Nanchang University, Cornell University and Fujian Normal University
Type: | Journal: Scientific reports | Year: 2016

Metabolic scaling theory (MST) posits that the scaling exponents among plant height H, diameter D, and biomass M will covary across phyletically diverse species. However, the relationships between scaling exponents and normalization constants remain unclear. Therefore, we developed a predictive model for the covariation of H, D, and stem volume V scaling relationships and used data from Chinese fir (Cunninghamia lanceolata) in Jiangxi province, China to test it. As predicted by the model and supported by the data, normalization constants are positively correlated with their associated scaling exponents for D vs. V and H vs. V, whereas normalization constants are negatively correlated with the scaling exponents of H vs. D. The prediction model also yielded reliable estimations of V (mean absolute percentage error=10.50.32 SE across 12 model calibrated sites). These results (1) support a totally new covariation scaling model, (2) indicate that differences in stem volume scaling relationships at the intra-specific level are driven by anatomical or ecophysiological responses to site quality and/or management practices, and (3) provide an accurate non-destructive method for predicting Chinese fir stem volume.


Gan G.,Key Laboratory of Plateau Lake Ecology and Global Change | Gan G.,Yunnan Normal University | Zhang W.,Key Laboratory of Plateau Lake Ecology and Global Change | Zhang H.,Key Laboratory of Plateau Lake Ecology and Global Change | And 4 more authors.
Hydraulic Engineering III - Proceedings of the 3rd Technical Conference on Hydraulic Engineering, CHE 2014 | Year: 2015

According to analyze environmental proxies of Qinghai Lake in southwest China, e.g., the grain-size, low frequency magnetic susceptibility (xlf), CaCO3 and Total Organic Carbon (TOC), with the AMS 14C datings and Principal Component Analysis (PCA), the evolution processes of climate environment was reconstructed since 15.0 cal. Ka BP. The results show that during 12.7 to 9.6 cal. ka BP, the southwest monsoon was stronger. During 9.6 to 5.0 cal. ka BP, the lake water level was continued to rise, the southwest monsoon was further enhanced. During 5.0 to 0.26 cal. ka BP, the climate was arid gradually. The intensifying human activity and land-use in the lake catchment since 0.26 cal. ka BP were associated with the ancient culture within Qinghai’s catchment. © 2015 Taylor & Francis Group, London, UK.


Long X.,Key Laboratory of Plateau Lake Ecology and Global Change | Long X.,Yunnan Normal University | Zhang W.,Key Laboratory of Plateau Lake Ecology and Global Change | Zhang H.,Key Laboratory of Plateau Lake Ecology and Global Change | And 4 more authors.
Hydraulic Engineering III - Proceedings of the 3rd Technical Conference on Hydraulic Engineering, CHE 2014 | Year: 2015

Qinghai Lake is located in the Tengchong County, Yunnan Province. The climate is affected by the Asian southwest monsoon. Based on the wavelet analysis, the climate change of Qinghai Lake are studied by the environmental proxies, such as grain-size, Total Organic Carbon (TOC), and carbonate content (CaCO3), magnetic susceptibility. Combine with the AMS14C datings, we use the wavelet analysis method to explore the climate periodic signal of Qinghai lake during the Holocene. The results show that the environmental proxies are exist -1000a, -500a, -200a cycles, and the -1000a, -500a cycles are obvious during the whole Holocene. It is reflects the characteristics of Asian southwest monsoon during the Holocene, which indicates that the monsoon from strong to weak, the mechanism of Southwest monsoon is solar activity. © 2015 Taylor & Francis Group, London, UK.


Zhang W.,Yunnan Normal University | Ming Q.,Yunnan Normal University | Shi Z.,Yunnan Normal University | Chen G.,Yunnan Normal University | And 4 more authors.
PLoS ONE | Year: 2014

Sediments from Xinyun Lake in central Yunnan, southwest China, provide a record of environmental history since the Holocene. With the application of multi-proxy indicators (total organic carbon (TOC), total nitrogen (TN), δ13C and δ15N isotopes, C/N ratio, grain size, magnetic susceptibility (MS) and CaCO3 content), as well as accelerator mass spectrometry (AMS) 14C datings, four major climatic stages during the Holocene have been identified in Xingyun9s catchment. A marked increase in lacustrine palaeoproductivity occurred from 11.06 to 9.98 cal. ka BP, which likely resulted from an enhanced Asian southwest monsoon and warm-humid climate. Between 9.98 and 5.93 cal. ka BP, a gradually increased lake level might have reached the optimum water depth, causing a marked decline in coverage by aquatic plants and lake productivity of the lake. This was caused by strong Asian southwest monsoon, and coincided with the global Holocene Optimum. During the period of 5.60-1.35 cal. ka BP, it resulted in a warm and dry climate at this stage, which is comparable to the aridification of India during the mid- and late Holocene. The intensifying human activity and land-use in the lake catchment since the early Tang Dynasty (∼1.35 cal. ka BP) were associated with the ancient Dian culture within Xingyun's catchment. The extensive deforestation and development of agriculture in the lake catchment caused heavy soil loss. Our study clearly shows that long-term human activities and land-use change have strongly impacted the evolution of the lake environment and therefore modulated the sediment records of the regional climate in central Yunnan for more than one thousand years. © 2014 Zhang et al.


PubMed | Key Laboratory of Humid Subtropical Eco geographical Process and Yunnan Normal University
Type: Journal Article | Journal: PloS one | Year: 2014

Sediments from Xinyun Lake in central Yunnan, southwest China, provide a record of environmental history since the Holocene. With the application of multi-proxy indicators (total organic carbon (TOC), total nitrogen (TN), 13C and 15N isotopes, C/N ratio, grain size, magnetic susceptibility (MS) and CaCO3 content), as well as accelerator mass spectrometry (AMS) 14C datings, four major climatic stages during the Holocene have been identified in Xingyuns catchment. A marked increase in lacustrine palaeoproductivity occurred from 11.06 to 9.98 cal. ka BP, which likely resulted from an enhanced Asian southwest monsoon and warm-humid climate. Between 9.98 and 5.93 cal. ka BP, a gradually increased lake level might have reached the optimum water depth, causing a marked decline in coverage by aquatic plants and lake productivity of the lake. This was caused by strong Asian southwest monsoon, and coincided with the global Holocene Optimum. During the period of 5.60-1.35 cal. ka BP, it resulted in a warm and dry climate at this stage, which is comparable to the aridification of India during the mid- and late Holocene. The intensifying human activity and land-use in the lake catchment since the early Tang Dynasty (1.35 cal. ka BP) were associated with the ancient Dian culture within Xingyuns catchment. The extensive deforestation and development of agriculture in the lake catchment caused heavy soil loss. Our study clearly shows that long-term human activities and land-use change have strongly impacted the evolution of the lake environment and therefore modulated the sediment records of the regional climate in central Yunnan for more than one thousand years.

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