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Volume 37,Issue 5
  • Distribution of soil organic carbon related to environmental factors in typical rocky desertification ecosystems
  • Authors:WANG Linjiao, LI Rui and SHENG Maoyin
  • Abstract:Karst rocky desertification is an important ecological issue hindering the socioeconomic development of the South China Karst region. In the present study, firstly, three typical rocky desertification regions-Bijie Yachi, Qingzhen Hongfenghu, and Guanling Huajiang, Guizhou Province, representing three different typical karst landforms-plateau mountain, plateau basin, and plateau gorge, respectively, were selected as experimental areas. Then, 90 sample plots with an area of 20 m×20 m each were established. The distribution of soil organic carbon (SOC) in relation to environmental factors (degree of rocky desertification, landform, vegetation, soil property, etc.) in these plots was determined using field measurements, laboratory detection, and mathematical statistics. The following results were obtained:1) The SOC content of karst rocky desertification ecosystems was low. The average content of the three experimental areas of Bijie Yachi (Plateau Mountain), Qingzhen Hongfenghu (Plateau Basin), and Guanling Huajiang (Plateau Gorge) was 23.42, 25.78, 26.03 g/kg, respectively. There was no significant (P=0.23) difference of SOC contents among the three different landform experimental areas. 2) Land cover change can affect the SOC content. The SOC content of virgin forest (31.32 g/kg) was the highest. With increased soil degeneration from virgin forest to gravel land, the SOC content first decreased and then increased. 3) The SOC content was correlated with soil physico-chemical properties. Specifically, the SOC content was extremely significantly positively correlated with total nitrogen content, hydrolyzed nitrogen content, available potassium content, total porosity, total phosphorus content, natural moisture capacity, field moisture capacity, capillary moisture capacity, and upper strata saturated permeability; significantly positively correlated with total phosphorus content and lower strata saturated permeability, and extremely significantly negatively correlated with soil bulk density. 4) The SOC content and plant diversity rich (R) and diversity (H) indices were extremely positively correlated. 5) There were significant differences of SOC contents between different degrees of rocky desertification. Along with increased degrees of rocky desertification, the SOC content initially decreased and then increased. Based on these results, the distribution pattern of the SOC content and its impact factors in karst rocky desertification ecosystems was clarified. These results have important implications for the protection of karst forest ecosystems, the reconstruction of rocky desertification ecosystems, and the response to global climate change.
  • DownLoad:Distribution of soil organic carbon related to environmental factors in typical rocky desertification ecosystems.PDF
  • Effects of litter and moss on soil respiration in a spruce forest in the Qilian Mountains, Qinghai
  • Authors:XIE Huanhuan, MA Wenying, ZHAO Chuanyan, GAO Yunfei, WANG Qingtao, GE Hongyuan, LIN Mei and HUANG Huiyun
  • Abstract:Soil respiration (Rs) is an important component of the terrestrial ecosystem carbon cycle and the main pathway for carbon transfer from the ecosystem to the atmosphere. Until recently, research has focused on the relationship between environmental factors and Rs, but the effect of litter and moss on Rs is poorly understood. Litter and moss are common forest-floor components, particularly in northern conifer forests and possibly affect soil respiration by regulating soil temperature, water, and carbon input. Understanding the effect of litter and moss is fundamental to accurately evaluate the global carbon efflux. To evaluate the contribution of litter and moss to total Rs, we selected the Tianlaochi catchment in the Qilian Mountains, Qinghai as our study area. Rs of soil under the spruce forest was observed for three years using an LI-8100 automatic instrument (LI-Cor, Inc, NE, USA). Simultaneously, soil temperature and moisture at a depth of 10 cm were recorded using a temperature probe and moisture sensor on the LI-8100. The results showed Rs had obvious monthly and diurnal variations in growing seasons-the monthly maximum Rs occurred in August and minimum in May, and the daily maximum value occurred at 1300h, except for the moss treatment, whose maximum was at 1500h. There was a significant difference in Rs among the three treatments(P<0.01); however, soil surface relative humidity, water content, soil temperature, and surface temperature did not differ significantly among the three treatments. Rs in soil covered by moss and litter, and that in bare soil, was 3.88, 3.31, and 2.28 μmol m-2 s-1, respectively. Moss and litter increased the soil temperature by 8.13% and 10.24%, respectively, more than that of bare soil. The relationship between temperature and Rs among three treatments was exponential. In addition, the correlation coefficient between Rs and soil temperature was higher than that between Rs and surface temperature. The temperature sensitivity (Q10) of soil covered by moss, litter, and bare soil was 5.47, 3.67, and 2.23, respectively. Rs showed a significant correlation with soil water content (VWC) in the bare soil treatment; when VWC was <34%, Rs increased with increased VWC, and when VWC > 34%, Rs decreased with increased VWC. Rs showed a strong negative relationship with VWC in moss and litter treatments. The contribution rates to Rs by moss and litter were 29.33% and 24.06%, respectively. From the present study, we can conclude that litter and moss are important factors affecting forest ecosystem Rs, and it is fundamental to consider the effect of litter and moss when Rs is calculated in forest ecosystems.
  • DownLoad:Effects of litter and moss on soil respiration in a spruce forest in the Qilian Mountains, Qinghai.PDF
  • Effects of precipitation increase on soil respiration of a Pinus yunnanensis plantation in a dry river valley area
  • Authors:LIU Wei, WANG Lihua, FU Rao, ZHOU Shixing, LIU Lin, WU Xiaohui and HUANG Congde
  • Abstract:The objective was to examine the effects of global climate change inducing precipitation pattern change on soil respiration (Rs) of Pinus yunnanensis plantation in dry river valley area of China(Shimian, Yaan, Sichuan). Based on average annual precipitation, Four treatments were set, ie, CK(natural state,0 mm m-2 a-1), A1(increasing precipitation 10%, 80 mm m-2 a-1), A2(increasing precipitation 20%, 160 mm m-2 a-1) and A3(increasing precipitation 30%, 240 mm m-2 a-1). Soil respiration rate was measured using LI-8100 monthly from Jun, 2013 to May, 2014. Results indicate that soil respiration rate exhibited obvious seasonal variation in Pinus yunnanensis plantation, with the maximum in July and the minimum in February. Precipitation increase treatment significantly increased Rs in A2 (by 12.88%), significantly decreased Rs in A3 (by 17.71%), and did not significantly affect Rs in A1. Soil respiration Q10 value calculated from soil temperature was increased under precipitation increase treatments. The relationship between soil respiration and soil moisture was weakened. Compared with soil temperature, soil moisture had less effect on the soil respiration. In wet season, microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) were increased significantly by increasing precipitation. In dry season, only MBN decreased significantly under precipitation treatments. Therefore, there was a significant effect of different increasing precipitation on soil respiration in a Pinus yunnanensis plantation in the dry river valley area. Moderate increasing rainfall would promote soil respiration, while superfluous increasing rainfall would inhibit soil respiration.
  • DownLoad:Effects of precipitation increase on soil respiration of a Pinus yunnanensis plantation in a dry river valley area.PDF
  • Effect of drainage on dissolved organic carbon and available nitrogen and phosphorus in the wetland forests of Xiaoxing'an Mountain
  • Authors:JIANG Shan, ZHAO Guangying, ZANG Shuying and SHAO Zongren
  • Abstract:The effect of drainage on soil dissolved organic carbon (DOC) in the Xiaoxing'an Mountain forests was investigated by selecting Larix gmelinii plantation wetlands of different ages (drain in 1974, drain in 1985, drain in 1992, and drain in 2003), as well as a natural forest swamp wetland (L. gmelinii marsh). The results showed that soil DOC content decreased vertically with soil depth for all sites. Compared with the natural forest wetland, the DOC content in all soil layers was lower (P<0.05). The soil organic carbon (SOC) content, DOC/SOC, and soil available nitrogen (N) in the surface layer (0-10 cm) of the natural forest swamp were all higher than those in the drained forests. In contrast, the available phosphorus (P) content was lower in the natural wetland than in the drained forests (P<0.05). In the soil surface (0-10 cm), the time since drainage was significantly negatively correlated with DOC, DOC/SOC, SOC, and soil N, and was significantly positively correlated with the available P (P<0.05). After drainage of the soil surface (0-10 cm), DOC and available N (ammonium nitrogen, nitrate nitrogen) were inversely proportional to the effective P (P<0.05). In the forest wetlands where drainage ditches were dug, the soil moisture status was changed to promote the forest growth. Overall, the area of the Xiaoxing'an Mountain forest wetlands covers 106.96 ten thousand ha, with great carbon sequestration potential. Its average carbon density was higher than natural forest carbon densities, as well as the carbon density of the forest vegetation in Heilongjiang Province. It therefore plays an important role in the regional carbon cycling. Since the 1970s, the wetlands in the Xiaoxing'an Mountain forests have been greatly influenced by human activities, and mainly by wetland drainage. Movement of soil DOC with wetland drainage occurred in the directions of the water movement. A portion of the soil DOC moved along the horizontal and vertical direction of the drainage ditches, or was lost directly to the water. At present, research on the impacts of human activities on DOC is mainly focused on how wetland reclamation for farmland changes DOC, as well as the effects of different land use patterns on soil DOC.In this study, we researched the forest swamps of the Xiaoxing'an Mountain forests. We conducted a quantitative study on the changes of soil DOC and SOC after drainage and transformation, in order to understand the role of DOC in the regional ecosystem's carbon cycle and the mechanisms of carbon transformation, in order to provide a theoretical basis for the management and sustainable development of the regional wetland ecosystems.
  • DownLoad:Effect of drainage on dissolved organic carbon and available nitrogen and phosphorus in the wetland forests of Xiaoxing'an Mountain.PDF
  • Carbon flux simulation of typical temperate and subtropical forest ecosystems in China based on model-data fusion approach
  • Authors:GE Rong, HE Honglin, REN Xiaoli, ZHANG Li, FENG Ailin, WANG Huimin and ZHANG Junhui
  • Abstract:Moisture effect on the carbon balance of terrestrial ecosystems is a key issue in global change research. It is crucial to accurately analyze the response of terrestrial ecosystem carbon cycle to moisture. However, the carbon flux models responding to environmental factors rarely consider the moisture effects on photosynthesis and respiration simultaneously; meanwhile there are still large uncertainties in model structures and parameters. Thus, this study was designed to (1) choose the optimal carbon flux model with accurate parameters for different ecosystems through model-data fusion approach, reducing the uncertainties of modeled results; (2) systematically analyze the influence of water factors on carbon flux simulation, including gross ecosystem productivity (GEP), ecosystem respiration (RE) and net ecosystem exchange (NEE). To consider the effects of moisture on both GEP and RE, we developed four different NEE models. Then, based on carbon flux and meteorological data during growing season from 2003 to 2009 in Changbaishan temperate mixed forest (CBS) and Qianyanzhou subtropical coniferous plantation (QYZ), Markov Chain Monte Carlo was employed to estimate model parameters, and Bayesian Information Criterion was applied to choose the optimal model for two forest ecosystems. The results showed that (1) the posterior values of model parameters were normally distributed, indicating that the parameters were well constrained by NEE. Photosynthetic and respiratory parameter values of CBS were higher than those of QYZ during the growing season. The model without vapor pressure deficit (VPD) overestimated the value of temperature sensitivity (Q10) and underestimated the value of basal respiration rate (BR) in QYZ; (2) the model considering VPD only was the optimal model for CBS,but its performance was not improved much. The modeled flux components were similar among the four models; (3) the model considering both VPD and soil water content (Sw) was the optimal model for QYZ, and its performance was improved significantly. The model ignored water factors overestimated 2% (21.85 g C/m2) of the total GEP, and 4.4% (38.02 g C/m2) of the total RE, and therefore, underestimated 7.8% (18.55 g C/m2) of the total measured NEE during the growing season.
  • DownLoad:Carbon flux simulation of typical temperate and subtropical forest ecosystems in China based on model-data fusion approach.PDF
  • The effects of forest disturbance on flow regimes of a small forested watershed in northern Daxing'anling, China
  • Authors:DUAN Liangliang, MAN Xiuling, YU Zhengxiang, LIU Yujie and ZHU Binbin
  • Abstract:The natural flow regimes of rivers have been threatened by climate change and increased human activities, which could consequently affect their heath and integrity. Forest disturbance and climate variability are two of the most critical drivers affecting hydrological processes in forested watersheds. Despite an increased understanding of the relationship between climate change and flow regimes, few investigations have been conducted on how forest disturbance influences flow regimes. Moreover, existing researches have not accounted for the effects of climate variability on flow regimes when assessing the effects of forest disturbance. In the present study, the paired watersheds approach, which can account for temporal and spatial variations of climate, was applied to a typical small forested watershed (<100 km2) in northern Daxing'anling to investigate the effects of forest disturbance on flow regimes. The results showed that low-flow regimes were more sensitive than high-flow regimes to forest disturbance. Even though the area of forest disturbance was only 6.74% of the total watershed area (Laogouhe watershed), the average magnitude (0.47 mm) of low flows was lower by 26.58% and the average variability (0.39) of low flows was higher by 36.77% than those of low flows (0.60 mm and 0.28, respectively) in the control watershed (Xiaobeigou watershed). Besides, the differences in low flow magnitude and variability between the paired watersheds were statistically significant (P<0.01). In contrast, the magnitude, duration, and variability of high flows in the disturbed watershed were greater than those in the control watershed, but no statistical significance was found, suggesting that the small forest disturbance did not significantly affect the flow regimes of high flows in the study region. Based on the results of the flashiness index, the flashiness of flows was significantly increased by forest disturbance. The flashiness index in the disturbed watershed was 0.078 during the whole study period, which is 1.37 times larger than that of the control watershed (0.057). These results indicate that the natural flow regimes of small forested watersheds in northern Daxing'anling are sensitive to forest disturbance. Since small-scale disturbance in the study area can lead to significant changes in flow regimes, more focus should be applied to forest disturbance and water resources in future management.
  • DownLoad:The effects of forest disturbance on flow regimes of a small forested watershed in northern Daxing'anling, China.PDF
  • Effects of wind frequency on the rates of photosynthesis and transpiration in Pinus sylvestris var. mongolica seedlings
  • Authors:ZHAO Halin, LI Jin, ZHOU Ruilian, YUN Jianying, FENG Jing and SU Na
  • Abstract:To understand the effects of frequent gusts of wind on the rates of photosynthesis and transpiration in Pinus sylvestris var. mongolica seedlings, a field wind-blowing experiment using a wind speed gradient of 0 (CK), 6, 9, 12, 15, and 18 m/s and four episodes of wind blowing was conducted in the spring of 2013 in the Horqin Sand Land of Inner Mongolia. The results showed that:1) Frequent wind blowing did not change the diurnal variation in the rates of photosynthesis and transpiration in seedlings, but resulted in in an extension of midday depression and a higher degree of dormancy in photosynthesis and transpiration. 2) Increasing the wind strength led to a significant decrease in the average daily rates of photosynthesis and transpiration, with a decrease of 27.6% and 22.3% in the 18 m/s-treated seedlings compared to the CK, respectively. With an increase in wind strength, stomatal conductance and intercellular CO2 concentrations first increased and then decreased, and were significant lower in all treatment groups as compared with the CK group, with the exception of intercellular CO2 concentration, which was higher in the 18 m/s group. 3) Increasing the wind-sand flow strength led to a significant increase in water-use efficiency, except for a significant decrease in the 18 m/s treatment group as compared with the CK group. In addition, the efficiency of sunlight energy use tended to decrease except for a significant increase in the 6 m/s-treatment group as compared with the CK group. 4) Decreases in the average daily rates of photosynthesis and transpiration resulted from a decrease in stomatal conductance, and changes in water-use efficiency and sunlight energy-use efficiency resulted from changes in the rates of photosynthesis and transpiration.
  • DownLoad:Effects of wind frequency on the rates of photosynthesis and transpiration in Pinus sylvestris var. mongolica seedlings.PDF
  • Mapping disturbance and recovery of plantation forests in southern China using yearly Landsat time series observations
  • Authors:SHEN Wenjuan and LI Mingshi
  • Abstract:Yearly Landsat imagery from 1986 to 2011 of a typical plantation region in Fogang County, Guangdong Province, southern China, was used as a case study. The pre-processing Landsat Ecosystem Disturbance and Adaptive Processing System (LEDPAS) algorithm was implemented to generate standard surface reflectance images to construct a Landsat time series stack (LTSS). The LTSS was fed to the Landsat-based detection of trends in disturbance and recovery (LandTrendr) algorithm to monitor long-term changes in plantation disturbance and recovery, followed by an intensive validation and a continuous 24 years change analyses on annual change, and disturbance amount and duration. Validations derived from two chosen sample plots of 4 km2 indicated that the LandTrendr-based mapped disturbance results strongly agreed with those derived from the visual interpretation of the pre-and post-disturbance multispectral images and visualization of the local disturbance documents, with an error of 0.1 km2. Results indicated that the forest disturbances that occurred in Fogang County were relatively drastic. An annual disturbance of 1000 hm2 was witnessed for most years of the study, and an annual disturbance of over 2000 hm2 occurred in 1987, 2002, 2004, 2005, 2006, 2007, and 2009. Particularly, the disturbance of 1987 and 2007 exceeded 6000 hm2. In comparison to forest disturbance, forest recovery areas were relatively stable. Through a trend analysis of forest disturbance and recovery in Fogang County, forest disturbance and recovery areas mapped in the late 1980s through 1990s were less than those mapped after 2000, and the trend was lower than that after 2000. Since 2000, the forest disturbance areas have gradually increased, with a slight increase in forest recovery, but the overall magnitudes of forest disturbance exceeded those of forest recovery. The area of forest disturbance with a duration of 1 year accounted for 38%, 28% for a duration of 2 years, 25% for a duration of 3 years, and 7% for a duration of 4 years; these disturbances were classified as abrupt and short-term disturbance events. Gradual forest disturbance and recovery events for a duration over 4 years existed, but the overall areas were less than 100 hm2/a, and were highly different from the areas of abrupt disturbance events. Prior to 2000, abrupt and gradual disturbance areas were almost equal, with a gentle change. After 2000, abrupt disturbance areas were greater than those of gradual disturbances, with a maximum of 2800 hm2, and both abrupt and gradual disturbances showed an undulatory increasing trend. Based on the history and status of forest disturbances in Fogang County, the factors contributing to the environmental disturbance of forest plantations were analyzed to develop effective forest management strategies and countermeasures. The current study demonstrated the need to use dense time series images to map forest disturbance and recovery events in plantation forests. This approach could provide qualitative, locational, and quantitative forest change results for the land use decision-makers and conservation communities, enabling the strategic development of sustainable forest management and provide effective data support to evaluate forest productivity and carbon storage.
  • DownLoad:Mapping disturbance and recovery of plantation forests in southern China using yearly Landsat time series observations.PDF
  • Vegetation restoration effects of rock cutting slopes in the cold region of China
  • Authors:ZHANG Xiao, ZHANG Hongyu, LU Zhaohua, CHEN Kaiyu, WU Jiaxing and DENG Xueqin
  • Abstract:With the rapid economic, scientific, and technological development, China's expressway network is increasingly improving. However, expressway networks can damage ecosystems, and generate a large number of high and steep slopes. Because these slopes can be dangerous, it is of great importance to restore them. The United States and other developed countries have a long history in ecological slope restoration, and currently, Japan is the world leader in the field of restoration techniques. In China, the efforts for ecological restoration are still behind other countries, although its ecological restoration techniques are developing, especially those for special geographical environments such as rock slopes. Compared with soil slopes, rock slopes are high, steep, and with relatively poor soil conditions. Furthermore, rock slopes are extremely unstable, which makes them difficult to recover. In China, numerous methodologies have been implemented to restore rock slopes. Currently, thick layer planting and eco-concrete technologies are widely used for restoration activities in China. However, these two methodologies are still imitated mechanically from other countries, and no particularly thorough, systematic, or comprehensive research is available. Thus, China's ecological restoration work is facing serious issues, especially in the cold region. Unlike other regions in China, the extremely low temperatures in the cold region hinder plant growth, because of diseases and the harsh environment. Many artificial slope plants used in this region have poor cold hardiness or stress resistance. This causes degradation of many artificial slopes, leading to a decrease in the vegetation cover, and death of native species even after a period of growth and reproduction.In the present study, the Arun Banner to Boketu expressway was chosen as the study area, in order to evaluate the restoration effects of thick layer planting and eco-concrete techniques. We also aimed to understand the successional stages, and determine the soil-plant relationships by analyzing the plant communities', Margalef index, Shannon-Weiner index, Pielou index, Jaccard index, and soil data. The results indicate that:1) the two techniques did not result in significantly different plant communities and similarity indices, although eco-concrete slope plant communities were closer to natural ones; 2) obvious differences were observed between the plant communities and similarity indices of shady and sunny slopes; 3) a specific increment in soil total nitrogen and organic matter content can promote the development of plant communities. In addition, an increase in soil available phosphorus content will inhibit this development; 4) Artemisia argyi, Artemisia integrifolia, Leymus chinensis, Stipa Baicalensis, Lespedeza daurica, Amorpha fruticosa, and Salix hsinganica are the most appropriate and effective species for use in this restoration work.Overall, this study can provide a basis for improving the application of both technologies in this region, to optimize species configuration, prevent secondary degradation problems, and provide a theoretical basis for future conservation and management measures.
  • DownLoad:Vegetation restoration effects of rock cutting slopes in the cold region of China.PDF
  • Spatio-temporal patterns of precipitation-use efficiency of grassland in Northwestern China
  • Authors:MU Shaojie, YOU Yongliang, ZHU Chao and ZHOU Kexin
  • Abstract:Precipitation-use efficiency (PUE) is an important indicator used to determine how net primary productivity (NPP) responds to variation in precipitation, especially in arid and semi-arid ecosystems. The objective of this study was to determine the spatio-temporal patterns of PUE and its response to climatic factors along the precipitation gradient. The Carnegie-Ames-Stanford Approach (CASA) model was employed to simulate NPP in Inner Mongolia during 2001-2010 based on MOD13A1 data and spatially interpolated meteorological data. PUE was calculated as the ratio of NPP to annual precipitation. The results showed that:(1) The multi-year average PUE of grassland in Northwestern China was 0.68 g C m-2 mm-1. Among various type of temperate grassland, meadow steppe had the highest PUE, whereas the lowest PUE was found for desert. Furthermore, there were significant differences between the PUE of different grassland types. For the alpine grassland, alpine steppe had a higher PUE than alpine meadow. (2) Spatially, the PUE of temperate grassland increased first, peaking at~472.9 mm/a, and then decreased with the precipitation gradient (R2=0.65, P<0.001). The relationship between desert PUE and precipitation followed a similar trend (R2=0.63, P<0.001), in which the highest PUE was found in the regions with annual precipitation of 263.2 mm. For the alpine meadow, PUE was low at both the dry (>100 mm) and the wet ends of the annual precipitation gradient, and peaked around 559.2 mm (R2=0.47, P<0.001). (3) Temporally, the inter-annual variation of PUE also responded differently to climatic factors in different precipitation ranges. In the area with precipitation of 200-1000 mm, PUE was positively correlated with precipitation. For the regions where precipitation was higher than 1050 mm, temperature had much greater effects than precipitation on the inter-annual variations of PUE.
  • DownLoad:Spatio-temporal patterns of precipitation-use efficiency of grassland in Northwestern China.PDF
  • Relationship between plant species diversity and functional diversity in alpine grasslands
  • Authors:DONG Shikui, TANG Lin, ZHANG Xiangfeng, LIU Shiliang, LIU Quanru, SU Xukun, ZHANG Yong, WU Xiaoyu, ZHAO Zhenzhen, LI Yu and SHA Wei
  • Abstract:The relationship between species diversity and functional diversity is currently one of the hot topics in ecology research. Determining the relationships between species and functional diversity in typical ecosystems of different regions can contribute to the development of biodiversity conservation theory. In this study, the main grassland ecosystems on the Qinghai-Tibetan Plateau, an alpine meadow and an alpine steppe, were selected to examine the relationships among species diversity, functional diversity, and primary productivity by using four species diversity indices, including the Patrick richness index, Shannon-Weiner diversity index, Pielou evenness index, and Simpson dominance index, as well as nine functional diversity indices, including the FAD functional trait distance index, MFAD functional trait mean distance index, FDp functional tree map index based on plots, FDc functional tree map index based on community, FRic functional volume index, FEve functional evenness index, Rao functional division two-times entropy index, FDiv functional division index, and FDis dispersion index. The aims of the study were to answer the following three questions:(1) what are the differences in plant species diversity and plant functional diversity between different types of alpine grasslands? (2) what are the relationships between plant species diversity and plant functional diversity in the alpine grasslands? (3) are there differences between the species diversity-ecosystem functioning (primary productivity) and plant functional diversity-ecosystem functioning relationships in the alpine grasslands? The results indicated that the alpine meadow showed higher species diversity, functional richness, and functional division than that by the alpine steppe. Furthermore, in the alpine meadow, the Patrick richness index was highly correlated with the functional indices FAD, MFAD, FDp, and FDc, as well as with the FDiv functional division index, and their correlations could be respectively expressed using a power function and two polynomial functions. In the alpine steppe, the Patrick richness index was strongly correlated with the functional indices FAD, MFAD, FDp, FDc, and FRic, and the Shannon diversity index and Simpson dominance index were highly correlated with the functional evenness index FEve; their correlations could be expressed by two polynomial functions. Moreover, the Pielou evenness index was highly correlated with the functional evenness index FEve, and their correlations could be expressed as an exponential function. Primary productivity of the alpine meadow was highly correlated with the Patrick richness index and FDiv functional division index, whereas primary productivity of the alpine steppe was highly correlated with all four biodiversity indices and the FDiv functional division index; all of their correlations could be expressed by two polynomial functions. Based on the results of this study, it can be concluded that plant species diversity, plant functional diversity, and their relationships with each other and with ecosystem function of primary productivity all varied between the different types of alpine grasslands. Therefore, in order to accurately evaluate the ecosystem functions of the alpine grasslands on the Qinghai-Tibetan Plateau, it is imperative to not only measure the plant species diversity but also the plant functional diversity, which is highly correlated with ecosystem function.
  • DownLoad:Relationship between plant species diversity and functional diversity in alpine grasslands.PDF
  • Spatio-temporal variations in climate-growth relationships of three hardwood tree species across the north Zhangguangcai Mountains, northeast China
  • Authors:SU Jinjuan and WANG Xiaochun
  • Abstract:Forests play a critical role in the global ecological balance. One of the major uncertainties in global climate change predictions is how the spatio-temporal dynamics of forests will be affected by global warming. Tree rings at different spatial and temporal scales can reflect the impacts of environmental change on tree growth, and can be critical for understanding the influence of climate change on forest ecosystems. Here, we investigated the spatio-temporal patterns of variation in climate-growth relationships of three common broadleaved tree species (Fraxinus mandshurica, Phellodendron amurense, and Juglans mandshurica) in a broadleaved Korean pine mixed forest across the north Zhangguangcai Mountains, northeast China. Tree-ring chronologies from three sample sites were established, transformed into principal component analysis (PCA), and analyzed through correlation analysis. With these analyses, climate factors limiting the radial growth were identified, as well as the detailed spatial radial growth-climate associations. The responses of the tree species at similar sites to climate factors differed significantly. Radial growth of J. mandshurica was limited by monthly total precipitation and minimum temperature, whereas P. amurense and F. mandshurica were mainly affected by monthly mean minimum temperature. This suggests that climate-growth relationships are affected by species-specific characteristics. With changes in temperature and precipitation patterns, the three hardwoods differed in their spatial growth response to climate factors. The radial growth of J. mandshurica in Fangzheng and Xidaquan was positively correlated with minimum June to August temperatures (P<0.05). In contrast, it was positively correlated in Fenghuangshan with minimum temperature and precipitation in May and June (P<0.05). The radial growth of P. amurense and F. mandshurica decreased from west to east with precipitation changes, since the correlation coefficients between tree-ring index and precipitation decreased from west to east. Temperatures in the north Zhangguangcai Mountains have increased since 1980, and the radial growth of the three hardwoods was consistent before 1980. Because climate factors affect growth differently, these boreal tree species showed inconsistent spatio-temporal responses to the recent warming, with J. mandshurica being probably the most sensitive species. Radial growth of P. amurense and F. mandshurica increased with rapid warming since 1980, whereas tree growth of J. mandshurica decreased after 1980. Therefore, J. mandshurica may be subjected to drought stress and a subsequent decline in radial growth in the north Zhangguangcai Mountains if global warming continues or exacerbates. In contrast, P. amurense and F. mandshurica may benefit from increased temperatures through enhanced radial growth. For future research, the spatio-temporal variation of growth-climate relationship of the three hardwoods could be explored further by investigating the tree ring anatomical and physiological responses.
  • DownLoad:Spatio-temporal variations in climate-growth relationships of three hardwood tree species across the north Zhangguangcai Mountains, northeast China.PDF
  • Relationships between artificial Haloxylon ammodendron communities and soil-water factors in Minqin oasis-desert ecotone
  • Authors:ZHAO Peng, XU Xianying, QU Jianjun, ZHANG Jinhu, MA Quanlin, ZHANG Huiwen, XU Gaoxing, MA Junmei and WU Yongmei
  • Abstract:The ecological safety of Minqin oasis depends on the evolution of artificial Halxylon ammodendron communities that acts as important barriers and promotes the continual development of the oasis. The relationship between artificial H.ammodendron communities and environmental factors was evaluated and analyzed using the quantitative ecology methods, two-way indicator species analysis (TWINSPAN) and canonical correspondence analysis (CCA) in this research. The results showed that (1) there were 4 types of associations in artificial H.ammodendron communities using TWINAPAN:AssociationⅠH. ammodendron+Nitraria tangutorum-Artemisia arenaria-Halogeton glomeratus; AssociationⅡH.ammodendron+Calligonum mongolicum-Agriophyllum squarrosum; Association Ⅲ H. ammodendron+Nitraria tangutorum+Phragmites australis; Association Ⅳ H. ammodendron+Tamarix ramosissima +Kalidium foliatum. (2) The first axis of CCA ordination represented the environmental gradient of water and soil organic matter, meanwhile soil electrical conductivity was reflected by second axis of CCA ordination. Forward selection and Monte Carlo test suggested that the ordination of environmental factors determining species distribution of artificial H. ammodendron communites was soil water content(10%) > soil organic matter(9.7%) > pH(8.8%) > available phosphorus(8.4%) > sand(7.8%) > groundwater depth(7.8%) > distance between oasis and desert(7.2%) > total nitrogen(6.9%) > electrical conductivity(6.7%).The classification results of TWINSPAN were exactly reflected in the CCA two-dimensional ordination diagram for samples and environmental variables. (3) PCCA revealed that soil factors such as soil water content, organic matter, sand, electrical conductivity, available phosphorus, total nitrogen, pH, and groundwater factors together explained 19.8% of the variance in species distribution of artificial H. ammodendron communities. Soil factors alone explained 15.6% of the variance, groundwater factors accounted for 1.1% of the variance, and the interaction between soil and groundwater factors explained 3.1% of the variance. The partitioning of variance using the PCCA helped identify the important habitat factors regulating species distribution of artificial H. ammodendron communities at the study site. However, the fact that more than half of the variance was unaccounted for by the factors studied suggested that other influences that were not examined could also play a role in determining the occurrence and distribution of artificial H. ammodendron communities, such as rain events, wind erosion, and sand burying, as well as banned and random events.
  • DownLoad:Relationships between artificial Haloxylon ammodendron communities and soil-water factors in Minqin oasis-desert ecotone.PDF
  • Effects of fertilizer addition on surface litter decomposition in the Tarim Desert Highway shelterbelt
  • Authors:ZHANG Xuemei, WANG Yongdong, XU Xinwen, LEI Jiaqiang and SUN Jingxin
  • Abstract:Litter decomposition determines the nutrient and carbon cycling processes and regulates nutrient return to the soil in many terrestrial ecosystems. Wood plant litter decomposition is a crucial biogeochemical process for carbon and nutrient cycling, especially in arid and nutrient-constrained ecosystems. However, the role of litter decomposition in extreme drought deserts and the determining factors remain debatable and poorly understood. The Tarim Desert Highway Shelterbelt consists of three artificial plant species that account for the majority of net primary productivity, and their litters are the major contributors to carbon and nutrient recycling. In such artificial desert shelter forests, the addition of fertilizer causes contradictory effects on litter decomposition and nutrient dynamics. This study aims to (1) examine how the addition of fertilizer affects surface litter decomposition and nutrient dynamics, and (2) determine the major factors influencing litter decomposition in arid deserts. The litterbag method was used to investigate the assimilative branches decomposition of Calligonum arborescens and Haloxylon ammodendron, and the branches decomposition of Tamarix ramosissima in the Taklimakan Desert Research Station. Filled litterbags were placed on soil surfaces at different plots in March 2013. Fertilizer addition and irrigation were implemented from March to November during the experiment. Litterbags were collected in May, July, September, and November of 2013, and in March and May of 2014. The mass remaining, elemental content (carbon, nitrogen, phosphorus, and potassium), and decomposition rates of litter were analyzed at each decomposition stage. Results showed that after 420 days of decomposition, significant differences were found among control (without fertilizer), addition of nitrogen fertilizer, and phosphorus and potassium compound fertilizer treatments. The mass remaining for the assimilative branches of C. arborescens, assimilative branches of H. ammodendron, and branches of T. ramosissima without fertilizer addition were 56.95%, 31.32%, and 50.24%, respectively. The decomposition rate of fertilizer treatments among different litters was the highest for the assimilative branches of H. ammodendron, followed by the branches of T. ramosissima, and then the assimilative branches of C. arborescens. The addition of phosphorus and potassium compound fertilizer significantly accelerated the litter decomposition rate of the three plant species, whereas nitrogen fertilizer increased the decomposition rate of the branches of T. ramosissima and restrained the decomposition rate of the assimilative branches of C. arborescens and H. ammodendron. During the decomposition process, litter nutrients presented net release patterns in the treatments without fertilizer. In contrast, the nitrogen, phosphorus, and potassium contents of the fertilizer treatments showed an accumulation-release pattern. The litter decomposition rate was determined by the initial phosphorus content and C/N and C/P ratios at the initial decomposition stage. However, the decomposition rate was controlled by the initial potassium, lignin, and cellulose contents and C/N, and lignin/N ratios at the final stage. Overall, the results suggest that the addition of fertilizer significantly changed the decomposition rate of surface litters, increased the amount of returned nutrients, and postponed the time of nutrient release. Improving soil fertility in the Tarim Desert Highway shelterbelt is essential in enhancing the quality of this valuable ecosystem. The initial litter C/N ratio is critical to surface litter decomposition in the Tarim Desert, and the initial chemical composition to surface litter decomposition rate varies at different decomposition stages.
  • DownLoad:Effects of fertilizer addition on surface litter decomposition in the Tarim Desert Highway shelterbelt.PDF
  • Influence of drought stress on the growth, leaf gas exchange, and chlorophyll fluorescence in two varieties of tung tree seedlings
  • Authors:LI Ze, TAN Xiaofeng, LU Kun, ZHANG Lin, LONG Hongxu, LÜ Jiabin and LIN Qing
  • Abstract:This study investigated the effects of drought stress on seedling growth and leaf photosynthetic physiological characteristics in two species of tung tree (Vernicia fordii and Vernicia montana). A pot experiment was conducted to study the effects of different water treatments (normal irrigation, light drought, moderate drought, and severe drought) on the growth, leaf gas exchange, and chlorophyll fluorescence of two kinds of tung tree seedlings. The results showed that light drought stress did not have any significant effect (P>0.05) on growth, leaf gas exchange, and chlorophyll fluorescence of the seedlings compared to that under normal irrigation. Modest drought stress significantly decreased (P<0.05) tung tree seedlings' chlorophyll SPAD value, growth, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), stomatal limitation value (Ls), maximum net photosynthetic rate (Pnmax), light saturation point (LSP), apparent quantum yield (AQY), dark respiration rate (Rd), maximum photochemical efficiency (Fv/Fm), actual photochemical quantum efficiency (ΦPSⅡ), electron transport rate (ETR), and photochemical quenching coefficient (qP). Severe drought stress increased intercellular CO2 concentration (Ci), water use efficiency (WUE), light compensation point (LCP), initial fluorescence (Fo), and non-photochemical quenching coefficient (NPQ) of the seedlings. Under modest drought stress, the decrease in net photosynthetic rate was primarily caused by stomatal and non-stomatal factors of the tung tree seedlings, while the decrease in net photosynthetic rate under severe drought stress was probably due to non-stomatal factors. Our results suggest that Vernicia fordii has a higher photosynthetic activity and efficiency, and a stronger adaptability to drought stress than Vernicia montana.
  • DownLoad:Influence of drought stress on the growth, leaf gas exchange, and chlorophyll fluorescence in two varieties of tung tree seedlings.PDF
  • The effect of environmental factors on stem sap flow characteristics of Haloxylon ammodendron (C. A. Mey.) Bunge in Minqin oasis-desert
  • Authors:ZHANG Xiaoyan, CHU Jianmin, MENG Ping, YAO Zengwang, WANG Hesong, LI Delu and JIANG Shengxiu
  • Abstract:In arid and semi-arid ecosystems, water resources are the key ecological factor restricting the structure and function of the oasis-desert ecotone. The objective of the present study was to determine the effect of environmental factors on the characteristics of stem sap flow and water consumption of Haloxylon ammodendron in the whole growing season. Thermal dissipation sap flow velocity probes (TDPs) and an automatic weather station were used to measure sap flow velocity in trunks of different diameters, and environmental factors such as air temperature (T), relative humidity (RH), solar net radiation (Rn), vapor pressure deficit (VPD), and precipitation (P), respectively, in the Minqin oasis-desert ecotone, Gansu Province, China, from June to November 2014. On clear days, the peak wave area of daily sap flow velocity (SV) of H. ammodendron trunks of different diameters gradually reduced with changing seasons, whereas the phenomenon "broad peak shape" of SV showed as excessive growth from June to August. The SV on cloudy or rainy days was lower than that on sunny days. The SV of different H. ammodendron trunk diameters often fluctuated, furthermore the larger the diameter, the higher the fluctuating during the growing season. However, there was no obvious consistency and relationship between SV and stem diameter. From June to November, the water consumption of H. ammodendron initially decreased, and the highest peak SV was in July. The larger the stem diameter, the water consumption was more higher. Environmental factors correlated positively with SV in different time scales and weather conditions. The weather condition effected the SV correlation of H. ammodendron significantly, where it was higher on sunny than on cloudy and rainy days. The correlation of SV with VPD was the highest with the total weather factors on sunny and rainy days, while the correlation of SV with Rn was the highest on cloudy days. In the study period, the correlation coefficitents between SV and T exceeded 0.842 (P<0.01). Rn was the second-most important influence on SV (R2=0.811, P<0.01), with the third influence factor of VPD (R2=0.769, P<0.01). The correlation of SV with soil moisture in the root area at 0-250 cm level points and 0-100 cm depths was the most significant. Therefore, from the results it could be deduced that H. ammodendron of Minqin is an efficient drought-resistant plant.
  • DownLoad:The effect of environmental factors on stem sap flow characteristics of Haloxylon ammodendron (C. A. Mey.) Bunge in Minqin oasis-desert.PDF
  • Effects of different crown densities on structure of Quercus wutaishanica populations in Huanglong Mountains, Northwest China
  • Authors:YU Shichuan, ZHANG Wenhui, LI Gang, YANG Bin and YU Biyun
  • Abstract:Quercus wutaishanica is one of Huang Long Mountains forest region main building group of species, 16 pieces of sample area were selected by typical sampling method, age class,static life table, survivorship curve, height class and crown width class, researching age class,static life table, survivorship curve, height class and crown width class were drew to survey the change rule in different crown density(crown density is 0.6、0.7、0.8 and 0.9) under different slope(shady slope and sunny slope). The results showed that Q. wutaishanica saplings respectively made the total individual number 57%、64%、36%、47% in different crown densities(crown density is 0.6、0.7、0.8 and 0.9), age class, static life table and survivorship curve indicate the Q. wutaishanica seedlings in four different crown densities, the Q. wutaishanica seedlings made the maximum proportion, and then the adult trees, saplings made the least proportion. The general performance of population age class, static life table, survivorship curve, height class and crown width class of Q. wutaishanica showed that Q. wutaishanica population in crown density of 0.7 was superior to the crown density of 0.6, 0.8 and 0.9. Saplings and small trees were the update bottleneck stage of Q. wutaishanica.The survivorship curve of Q. wutaishanica was belong to R.PearlⅢ type, fluctuated least when the crown density was 0.7. The proportion of seedlings, saplings and small trees in sunny slope was higher than shady slope, while the proportion of mature stand in sunny slope was less than shady slope. Except the height class a, height classes of sunny slope were more concentrated in the height class c, d, and e, while height classes of shady slope were more concentrated in the height class d, e, and f. In sunny slope, Crown breadth class distributed under 5m, while crown breadth of shady slope mainly distributed under 3.5m. In both the sunny slope and shady slope, crown density of 0.7 is more suitable for Q. wutaishanica to update and grow, which can be used as ideal conditions of tending thinning in Northwest of China.
  • DownLoad:Effects of different crown densities on structure of Quercus wutaishanica populations in Huanglong Mountains, Northwest China.PDF
  • Non-agricultural landscape structure and the effect on plant species diversity in agricultural landscapes: a case study in Fengqiu County
  • Authors:FENG Shu, TANG Qian, LU Xunling, DING Shengyan, JIA Zhenyu and LIANG Guofu
  • Abstract:Non-agricultural habitat is an important part of the agricultural landscape, and its complex structure and function play a vital role in maintaining and improving the biodiversity of the agricultural landscape. However, there is widespread evidence that the highly intensive global development of modern agriculture has led to the disappearance of many non-agricultural habitats, resulting in a simpler agricultural landscape. Therefore, the agro-ecosystem functions and services have been seriously damaged. Consequently, for the sustainable development of agriculture, studying the relationships between agricultural productivity and biodiversity, and landscape pattern and ecosystem functions and services are fundamental. To explore the structural attributes of non-agricultural landscape elements and the effect on plant species diversity in typical agricultural landscapes, we established a study area and developed 42 plots in Fengqiu County, Henan Province, which is a typical agricultural region in the lower reaches of the Yellow River. Within these plots, the vegetation in non-agricultural habitats (artificial forests, hedges, and ditches) was investigated using the Braun-Blanquet method. Based on remote sensing imagery and landscape pattern analysis, we extracted and classified the non-agricultural habitats of each sample within 1 km using ArcGIS 10.0, and analyzed the composition, structure, and spatial configuration of non-agricultural landscape elements. The results showed that 186 species belonging to 50 families and 164 genera were found in the study area, and six dominant families (Compositae, Gamineae, Leguminosae, Cruciferae, Labiatae, and Solanaceae) account for 51.6% of all species. The species diversity of artificial forests and hedges was relatively high, whereas the species composition of the ditches was different to the other habitats. In different types of non-agricultural landscape structure, the highest species richness of plants was found where the proportion of artificial forests was similar to hedge/ditches. The landscape metrics directly affect plant species diversity in different non-agricultural habitats, and the influence of landscape fragmentation and human disturbance is significant. From the results, to increase the quantity and quality of non-agricultural habitats in agricultural landscapes in the future, we should transform the non-agricultural landscape elements. New non-agricultural habitats should be developed, and the proportion of different types of habitats should be increased by adjusting the spatial structure and configuring different landscape elements. This would enhance the effective management and sustainable development of the agricultural landscape in the future.
  • DownLoad:Non-agricultural landscape structure and the effect on plant species diversity in agricultural landscapes: a case study in Fengqiu County.PDF
  • Potential erosion-resistant species analysis in the hill-gully region of the Loess Plateau
  • Authors:KOU Meng, JIAO Juying and YIN Qiulong
  • Abstract:The Loess Plateau is well known for its severe soil erosion. Soil erosion severely interferes with the process of plant development and succession. However, plants do survive in this region of very serious soil erosion. These individuals can overcome stress and disturbance due to soil erosion through various breeding strategies, as well as through morphological and physiological compensation. Therefore, a plant is considered erosion-resistant when it not only has survived and adapted to the soil erosion environment, but it can also protect and improve the soil, prevent further soil erosion, regenerate itself, and maintain the plant community's stability and sustainable development. This study was based on several years (2003-2014) of vegetation survey data of the Yan river basin in the hill-gully region of the Loess Plateau. The research objective was to select potential erosion-resistant species, and subsequently illustrate their distribution characteristics and their survival and propagation ability. The definition of erosion-resistant species and Braun-Blanquet phytosociology methods were used to select potential erosion-resistant species. The main results were as follows:1) A total of 42 potential erosion-resistant species were selected, which belong to 18 families and 33 genera. Gramineae, Leguminosae, Compositae, and Rosaceae species accounted for 66% of the total potential erosion-resistant species. 2) Phanerophyte, chamaephytes, and hemicryptophytes were the main plant life forms, and they accounted for 85% of the total erosion-resistant species. Shrubs or small shrubs, and perennial herbs were the main plant growth forms, and they accounted for 76% of the total erosion-resistant species. Xerophyte and mesophyte plants were the main plant water ecological types, accounting for 78% of the total erosion-resistant species. Furthermore, combined with the climatic conditions of study area, the 42 potential erosion-resistant species could be divided into three types:eurytopic species, medium amplitude species, and stenotic species. 3) Overall, 55% of the species were erosion-resistant, having a maximum cover over 50%, and could be the structural or single dominant species in a community. Maximum cover of the other species was less than 50%, and these species usually were the co-dominant species. All potential erosion-resistant species had a high cover and aboveground biomass, indicating that these species could adapt to different erosion environments and grow adequately. 4) Almost all 42 potential erosion-resistant species had a soil seed bank and seedling emergence, and 60% erosion-resistant species had canopy seed bank. Except for annual plants, allspecies were able to reproduce asexually. This result indicated that the potential erosion-resistant species could maintain their own survival and reproduction. 5) From the 42 potential erosion-resistant species, 13 had a basal stem-shoot architecture, with a large crown that can protect the base soil. Furthermore, eight species have an expanding shoot architecture, which display a strong ability to protect the soil and intercept sediments. In addition, six species have dense shoot architecture, and seven have a tussock-forming shoot architecture. Both types can effectively intercept sediments. In conclusion, the potential erosion-resistant species, which only occupied 13% of the total species recorded, had a seed and seedling bank. Furthermore, the perennial plants mainly employed vegetative reproduction, and could maintain their own survival and reproduction. Because the plant crowns can protect the soil surface and plant base stems can intercept sediments, a mound can be formed in the plant base, which will effectively control soil erosion.
  • DownLoad:Potential erosion-resistant species analysis in the hill-gully region of the Loess Plateau.PDF
  • Variation in woody plant functional traits of the tropical cloud forests in Bawangling, Hainan Island
  • Authors:KANG Yong, XIONG Menghui, HUANG Jin, LONG Wenxing, YANG Xiaobo, ZANG Runguo, WANG Xixi and LIN Deng
  • Abstract:The variation in plant functional traits can help us understand adaption mechanisms to different environments and predict the distribution of species and environmental changes. Twenty-one, 20 m×20 m plots were established and divided into 336, 5 m×5 m subplots in the tropical cloud forests in Bawangling, Hainan Island. Functional traits (i.e., leaf area[LA], leaf dry weight[LDW], leaf mass per area[LMA], leaf chlorophyll content[Chl], leaf thickness[LTh], and wood density[WD]) of all trees and shrubs with diameter at breast height over 5 cm, as well as soil nutrient contents, were measured in all plots. The magnitude of variation in each functional trait at individual plant, within-species, among-species, and community levels were assessed using a generalized linear model, whereas the relationships between soil nutrients and functional traits were examined using a stepwise linear regression. Results showed that the ranges of explained variance for LDW, LMA, CHl, LTh, LA, and WD were 0.06-0.47, 0.09-0.35, 0.35-0.72, and 0-0.07 for the individual, within-species, among-species, and community levels, respectively. This indicates that the magnitude of variation in functional traits was the highest at the among-species level and the lowest at the community level. The stepwise regression analysis showed that the changes of functional traits at all studied scales were significantly correlated with soil organic matter, nitrogen, and phosphorus.
  • DownLoad:Variation in woody plant functional traits of the tropical cloud forests in Bawangling, Hainan Island.PDF
  • Influence of pore confined groundwater depth on the groundwater quality of the alluvial coastal plain of Yancheng
  • Authors:MA Junting, CHEN Suozhong, HE Zhichao and ZHU Xiaoting
  • Abstract:Pore confined groundwater is an important fresh water resource for human beings. Pore groundwater is stored in systems of loose sedimentary aquifers. The spatial structure of the aquifer (or aquifer group) determines not only the spatial distribution pattern of groundwater, but also has some influence on the groundwater quality. Based on hydro-geological data and groundwater quality monitoring data collected between 2005 and 2014in the Yancheng coastal plain in China, methods including GIS and ANOVA were used to study the relationship between groundwater quality and the third confined aquifer buried depth. The groundwater quality dynamic evolution characteristics are also analyzed. Based on the conclusions, some recommendations are proposed to the local water resources management department. Firstly, based on the hydrogeological data in the study area, the buried depth Digital Elevation Model(DEM) was constructed and divided into 10 grades. The correlation between water quality factors and the aquifer buried depth was analyzed using variance analysis. The least significant difference method was used to determine the influence of different grading intervals on water quality factors. The average value of the monitored data for each year and for each buried depth interval was counted and time varying process curves of water quality factor levels were plotted to show the spatial and temporal variation of water quality factors with aquifer depth. The results showed that:in the study area, the III confined aquifer buried depth is mostly located between -118.9 m and -85.45 m. Owing to the variety of groundwater hydrogeological condition and different buried depths, some correlation between typical groundwater quality and aquifer buried depth is presented:Mineralization degree, total alkalinity and total bacterial count show the highest correlation with groundwater buried depth (69.67%, 75.76% and 58.09% respectively). Correlation between total hardness factor and depth is moderate (49.18%). The potassium permanganate index is less influenced by the buried depth (35.2%). It was found that, the correlation between each factor and the groundwater buried depth in each buried depth grading interval showed significantly different dynamic evolution characteristics. In the area where the aquifer was deeply buried (-160.8 m to -99.12 m), the total hardness, degree of mineralization and total number of bacteria were significantly affected by the buried depth. The potassium permanganate index content only showed a significant difference with depth in specific depth intervals (between -99.12 m and -92.91 m and between -85.45 m and -75.09 m). In addition, water quality factors showed different spatial distribution characteristics:the area with higher potassium permanganate index and total bacteria is mainly located between Sheyang county and Huangsha Port. The highest mineralization factor content values were found in the middle and western regions, total alkalinity and total hardness factor varied little, the total alkalinity was slightly lower in the shallow buried area, and the total hardness showed some upward trend.
  • DownLoad:Influence of pore confined groundwater depth on the groundwater quality of the alluvial coastal plain of Yancheng.PDF
  • Effects of soil fauna on winter litter humification along an altitudinal gradient in cold ecosystems in western Sichuan
  • Authors:TAN Yu, YANG Wanqin, LIAO Shu, PENG Yan, LI Jun and WU Fuzhong
  • Abstract:Foliar litter humification is one of the main mechanisms of carbon sequestration, and is essential in forming soil organic matter from foliar litter. Soil fauna is a type of decomposer that can influence litter humification. It was previously believed that soil fauna were dormant during the winter in cold biomes, and thus their activities were not considered to affect litter humification. However, recent studies have documented that some cold tolerant soil fauna remain active during the winter. However, little is known about the effects of soil fauna on litter humification during the winter in cold biomes. Therefore, a field experiment with different sizes of litterbags was conducted on three cold biomes along different altitudinal gradients in the eastern Tibet Plateau. Two species were selected to study litter decomposition at each of the three biomes:Betula albo-sinensis and Abies faxoniana in the subalpine forest at 3000 m, Sabina saltuaria and Salix paraplesia in the alpine forest at 3600m, and Ajania nubigena and Carex atrofusca in the alpine meadow at 4000 m. Litterbags were placed before the soil completely froze in November, 2013. Litterbags were sampled at the onset of three stages-freezing, deep freezing, and thawing-from 2013 to 2014. Tone coefficient (ΔlogK) and optical density value (E4/E6) were analyzed to determine the litter humification levels. The results showed that soil fauna promoted leaf litter humification as the temperature decreased, and suppressed leaf litter humification as the temperature increased during the winter in cold ecosystems. The effects of soil fauna on the process of leaf litter were regulated by altitude and litter species. The effect of soil fauna on leaf litter humification decreased as the altitude increased. Soil fauna increased litter humification at 3000m during the deep freezing stage and at 3600m at the onset of the freezing stage. However, soil fauna inhibited litter humification at 4000m during the thawing stage. Furthermore, soil fauna did not affect litter humification at other altitudes and sampling stages. The effects of soil fauna on litter humification rate at the onset of freezing stage were higher than those of the deep freezing stage and thawing stage, and humification rate peaked during the deep freezing stage. These results suggest that the activities of soil animals could promote humus formation from litter as the temperature decreases, indicating a possible increase in soil carbon sequestration. Together, these data provide a new understanding of soil organic matter formation and the carbon budget in cold ecosystems.
  • DownLoad:Effects of soil fauna on winter litter humification along an altitudinal gradient in cold ecosystems in western Sichuan.PDF
  • Physiological response and changes in swimming performance after thermal acclimation in juvenile chinese fire-belly newts, Cynops orientalis
  • Authors:LU Hongliang, GENG Jun, XU Wei, PING Jun and ZHANG Yongpu
  • Abstract:The thermal acclimatory capacity of a particular species determines its tolerance to environmental changes and affects its survival under future changing climatic conditions. Acclimation effects on physiological traits have been determined in many fish and frog species, but rarely in newts or salamanders. In the present study, we evaluated the physiological acclimatory response of newts. A total of 48 juvenile Chinese fire-belly newts (Cynops orientalis) were collected and acclimated to 15℃, 20℃, and 25℃, which represented the low, intermediate, and high environmental temperatures experienced by C. orientalis during their active period, respectively, over the course of 4 weeks. The locomotor (swimming) performances of individuals were measured at the same three test temperatures in a glass tank (150 cm×10 cm×15 cm) filled with water to a depth of 5 cm, and the critical thermal minimum (CTMin) and maximum (CTMax) were determined using a dynamic method. The thermal resistance range (TRR) was calculated as the difference between CTMax and CTMin, and acclimation response ratio (ARR) of CTMin and CTMax was obtained by dividing the tolerance change by the change in acclimation temperature. The results from repeated-measures ANOVA analyses revealed that newt swimming speeds were significantly affected by the acclimation and test temperatures. Despite no statistically significant difference, low and intermediate temperature-acclimated newts had relatively high mean swimming speeds at 15℃ and 20℃, respectively, while the high-temperature-acclimated newts had superior swimming speeds at 25℃. Similarly, at 15℃, low temperature-acclimated newts swam faster than those acclimated to a high temperature. However, at 20℃, intermediate temperature-acclimated newts swam faster than low or high temperature-acclimated individuals, while at 25℃, high and intermediate temperature-acclimated newts swam faster than those acclimated to low temperature. Thus, our data supports the beneficial acclimation hypothesis, which predicts that acclimation to a particular temperature enhances the animal's performance or fitness at that temperature. Our results also indicate that temperature acclimation shifts the thermal sensitivity of swimming performance in C. orientalis since low temperature-acclimated newts appear to have lower thermal sensitivity levels than those acclimated to high temperature. Both CTMin and CTMax were significantly enhanced at higher acclimation temperatures, suggesting that juvenile newts acclimated to low temperatures are more resistant to low temperatures and less resistant to high temperatures, whereas those acclimated to high temperatures are more resistant to high but less resistant to low temperatures. These results are consistent with previous studies focused on the various ectothermic vertebrate species analyzed to date. The TRR of newts was not affected by acclimation temperature, while the ARR of CTMax (0.26) was higher than that of CTMin (0.09) at acclimation temperatures between 15℃ and 20℃, but lower at acclimation temperatures between 20℃ and 25℃ (CTMax:0.16 vs CTMin:0.21). These results are consistent with previous predictions that the magnitude of the change in CTMin or CTMax slowly decreases and ultimately approaches zero as the acclimation temperature gradually reaches its thermal limits. Inter-species differences in thermal physiological response to acclimation in amphibians may be correlated with differences in thermal environments in their natural habitats.
  • DownLoad:Physiological response and changes in swimming performance after thermal acclimation in juvenile chinese fire-belly newts, Cynops orientalis.PDF
  • Reproduction rhythm of captive forest musk deer (Moschus berezovskii) at the Maerkang Musk Deer Farm: parturition timing and synchrony
  • Authors:SUN Junping, CAI Yonghua, YANG Ying, WANG Jing, FU Wenlong, CHENG Jianguo and MENG Xiuxiang
  • Abstract:This study was conducted in 2013 from March to October, at the Maerkang Musk Deer Farm (MMDF), Sichuan Province. The birth dates of 178 captive Forest musk deer were recorded and analyzed to determine the temporal fawning patterns, for which parturition timing, synchrony, and the potential influencing factors were explored. The results showed a strong seasonality in the parturition patterns of captive forest musk deer, and all parturitions occurred within a range of 66 days in the three months from May to July. The average fawning date was 25 May (n=178) and the majority of births (75%) happened within 22 days from 7 to 28 May. The parturition seasonality of captive forest musk deer at MMDF was adapted to the local strong seasonal patterns of temperature, precipitation, and food resources in Maerkang. Moreover, although the parturition pattern was not strongly correlated to the age of the captive females (r=-0.121, P>0.05), the sub-adult females were inclined to fawn (26 May, n=75) later than the adults (24 May, n=95) and the old deer (21 May, n=8). However, this difference in parturition timing was not significant (P>0.05). Furthermore, no significant difference was observed among the different enclosures (P>0.05), although the females in the original enclosures with a brick surface were inclined to fawn earlier (22 May, n=62) than those in the refined enclosures with an earth surface (26 May, n=116).
  • DownLoad:Reproduction rhythm of captive forest musk deer (Moschus berezovskii) at the Maerkang Musk Deer Farm: parturition timing and synchrony.PDF
  • Studies on body condition scoring and influencing factors in captive forest musk deer
  • Authors:CAI Yonghua, SUN Junping, YANG Ying, WANG Jing, FU Wenlong, ZHU Ping, ZHENG Chengli, LI Ning, SHI Lei and MENG Xiuxiang
  • Abstract:The forest musk deer (Moschus berezovskii) has been endangered owing to the habitat loss and musk exploitation, and musk deer farming has become an effective measure to conserve wild populations and provide medicinal musk sustainably. In musk deer farming, the health condition of captive individuals will be closely related to the reproduction and the musk production. In this study, the body condition of captive forest musk deer (299 females and 287 males) in the Maerkang musk deer farm (MMF) was surveyed during July and October 2012, using the quantified criteria system. Furthermore, the potential effects of certain influencing factors were analyzed. The results showed that, the average body score of captive forest musk deer was 3.49 (±0.02, n=586), and most of individuals (59.56%, n=349) scored higher than the average. The body condition of all females (3.50±0.02) was better than that of all males (3.49±0.03), but the difference was not statistically significant (P > 0.05). The body condition of adults (4-9 years old) (3.59±0.02, n=291) was significantly better than that of older deer (older than 10 years) (3.38±0.09, n=27) and sub-adults (2-3 years old) (3.35±0.03, n=184; P < 0.01). No significant correlation was found between musk deer's body condition and age (r=0.07, P > 0.05), but the body condition scores of the adults and sub-adults were highly significantly correlated with the animals' age (sub-adults:r=0.19, P < 0.01; adults:r=-0.16, P < 0.01); moreover, a significant negative correlation was observed between old individuals' and their age (r=-0.23, P > 0.05). The S model y=e1.2811-0.0885/a (R2=0.051, df=500, F=26.74, P < 0.01) fitted the relationship between the score of captive deer and its age. Furthermore, the body condition score of musk deer in the enclosures with earth-ground was higher than those in the enclosures with brick-ground.
  • DownLoad:Studies on body condition scoring and influencing factors in captive forest musk deer.PDF
  • Effect of silicon addition to rice plants on Cnaphalocrocis medinalis feeding and oviposition preference
  • Authors:HAN Yongqiang, GONG Shaolong, WEN Lizhang and HOU Maolin
  • Abstract:Rice is a silicon (Si)-accumulating plant species. It is estimated that a rice crop producing 1,000 kg yield will remove 130 kg Si from the soil, twice as much as the combined absorption of nitrogen, phosphorus, and potassium. The rice leaf folder (LF), Cnaphalocrocis medinalis (Guenée), is one of the most destructive rice pests in Asian rice-producing countries. Recently, major outbreaks of LF have been reported in many Asian countries including China, severely threatening rice production. Rice varieties resistant to LF have either a high Si cell density or high Si content in the leaf blade. Currently, LF populations are principally managed with chemical insecticides that have caused high residual, insecticide resistance and a resurgence of pests. Alternatively, cultivar resistance and crop management including Si amendment are being developed. There is increasing evidence showing a positive association between high plant Si content and resistance to insect herbivory in monocots and dicots. Si amendment can influence insect herbivores in several ways, including acting as a physical barrier, deterring feeding behavior, reducing food consumption efficiency and performance, and effecting herbivores at a transcriptional level through differential regulation of plant genes. In the present paper, we report the effects of Si addition to rice plants on feeding and oviposition preference and damage by the LF. We used the susceptible rice cultivar Taichung Native 1 (TN1) and added Si at 0.32 (high rate), 0.16 (low rate), and 0 g Si/kg soil (control). In preference tests, LF larval settlement and egg deposition on rice plants amended with Si at both the low and high rates were significantly reduced. Si amendment at the high rate significantly increased the Si and soluble sugar contents and C/N ratio and decreased the nitrogen content in rice leaves compared with the control; Si addition at the low rate significantly increased the C/N ratio and decreased the nitrogen content in rice leaves in comparison with the control. The damage rates decreased significantly in rice plants amended with Si at the high rate than that of the control. Our results indicate that Si addition to susceptible rice plants could enhance plant resistance to LF through reduced feeding and oviposition preference.
  • DownLoad:Effect of silicon addition to rice plants on Cnaphalocrocis medinalis feeding and oviposition preference.PDF
  • Nematode (Enoplida) diversity in sediment samples collected from the Clarion-Clipperton Fracture Zone
  • Authors:ZHANG Shun, LIN Shiquan, MENG Fanxu, WU Min, XU Xuewei and WANG Chunsheng
  • Abstract:Marine free-living nematodes (Phylum Nematoda) are widespread and abundant in marine sediments, often representing 70%-90% of the benthic metazoans. However, marine nematode taxonomy is severely underdeveloped, and about only 4,000 species of free-living marine nematodes have been described. Nematode identification by using traditional morphological methods is time consuming and expensive. Some marine nematodes are small, displaying similar morphological characters and are difficult to identify by traditional methods. Molecular technology, or "barcoding," offers the potential of a fast and objective way of species identification. The small and large subunit ribosomal DNA (SSU rDNA and LSU rDNA) gene-based phylogenetic analysis is a powerful tool for clarifying evolutionary relationships among nematode taxa. The order Enoplida is one of the most important groups of marine nematodes. Many enoplids are possibly active predators, and play important ecological roles in marine environments. Here we reported the isolation of 26 nematodes, belonging to Enoplida, from sediment samples collected at four sites in the Clarion-Clipperton Fracture Zone of the Pacific Ocean. The specimens were preserved in DESS solution (20% dimethyl sulphoxide, 0.25 mol/L disodium EDTA pH 8.0, saturated with NaCl) immediately after collection. Each sediment sample was rinsed through a 38-μm sieve using filtered seawater, and extracted using the Ludox flotation method. Nematodes were placed on temporary slides and observed using a Leica DM5500 microscope. After image capturing, each specimen was washed, cut into several pieces, transferred into micro-centrifuge tubes, and digested with Proteinase K. A series of frozen specimens was subsequently thawed and subjected to PCR amplification of the 18S rRNA gene and D3 expansion segments of the 28S rRNA gene. Sequences were analyzed and compared with published data from GenBank by means of a BLAST search. Phylogenetic trees were constructed using the neighbor-joining, maximum likelihood, and maximum parsimony methods with the MEGA5 program package, after multiple alignment of the data by CLUSTAL W. Based on morphological and molecular analyses, these 26 nematodes were classified into six families and eight genera, among which Oxystominidae was the most abundant family, accounting for 57.7%. The other families included Anticomidae (19.2%), Phanodermatidae (7.7%), Oncholaimidae (7.7%), Ironidae (3.85%), and Enchelidiidae (3.85%). At the family and genus level, the community composition at adjacent sites during the same period showed similar results, but the abundance was different. Sixteen sequences of rRNA gene were obtained in the present study and their similarity to the sequences in GenBank ranged from 94 to 99%. According to the results from BLAST, all sequences could be identified at the level of family, while 84.6% of the 16 sequences could be identified at the level of genus. The results from morphological and molecular analysis showed high consistency, which suggested that molecular barcoding is an efficient method to identify deep-sea nematodes. Phylogenetic trees constructed from the sequences of 18S and 28S rRNA gene showed similar topological structures; the species of Oncholaimidae and Enchelidiidae were clustered into one group, whereas those of Phanodermatidae and Anticomidae were clustered into another group, indicating their close genetic relationships.
  • DownLoad:Nematode (Enoplida) diversity in sediment samples collected from the Clarion-Clipperton Fracture Zone.PDF
  • Ecological distribution of bacterioplankton and virioplankton in the north of South China Sea in spring
  • Authors:ZHANG Zhe, WANG Xiaohong, GONG Xiuyu, LIU Yong, LIAO Xiuli, CAI Wengui and HUANG Honghui
  • Abstract:According to the concept of Microbial Loop, bacteria and virus play important role in organic matter recycling and energy flowing in marine ecosystem, and meanwhile influence many biogeochemical and ecological processes. Marine bacterial and viral ecology has become hotspot in current studies. The South China Sea (SCS) is one of the largest marginal seas in Northwest Pacific, and has already been proved to be oligotrophic. The SCS has attracted great attention due to its economic and strategic importance in recent years. Although the abundance and diversity of bacterioplankton in coastal waters and northern upwelling regions of SCS are well documented, little is known about bacterioplankton and virioplankton distribution in the central and northern area, especially the area near 18°N in SCS, and further investigations should be carried on to study the ecological functions of microbes in this region. In order to study the ecological distribution and function of bacteria and virus in this area, a cruise was conducted during Spring 2014 and water samples were collected from 27 stations. Water column at each station was divided into five layers, which were 5, 25, 75, 150 and 200 m layers respectively. Water samples were collected by Niskin bottles, fixed with glutaraldehyde and stored at liquid nitrogen immediately. Bacterioplankton and virioplankton abundances at different water layers and stations were measured by flow cytometry method. Horizontal and vertical distribution and its correlation with environmental variables, such as temperature, depth, salinity, dissolved oxygen, chlorophyll a and inorganic nutrients were also analyzed. The results showed that the bacterioplankton and virioplankton abundances in the upper 200 m of the water column were 1.28×104-9.96×105 cells/mL and 4.69×105-5.39×107 cells/mL, respectively. Their abundances were similar to the results in other oligotrophic oceans and lower than that of the coastal areas. With the increase in water depth, the abundances of both bacterioplankton and virioplankton decreased gradually in the vertical direction and in correlation with the euphotic layer, but no significant distribution pattern was detected in the horizontal direction. The variation in bacterioplankton and virioplankton abundance was significantly correlated with water temperature, pH, and dissolved oxygen, but negatively correlated with water depth, salinity, active phosphorus, silicate, nitrate, and total nitrogen (P<0.01). We conclude that bacterioplankton and virioplankton abundances were regulated by multiple environmental factors. Virus-to-bacteria ratio (VBR) reflects the relationship between bacteria and virus. The average VBR in this region was 32.23. The maximum value was 264.63 and it was observed at the 75 m layer of S7 station. The minimum value was 4.80 and it was detected at the 25 m layer of S11 station. A VBR value lower than 100 was detected in 95.6% of the stations. No significant correlation was found between VBR and environmental variables (P>0.05), however, a significant negative correlation was observed between bacterioplankton and VBR (P<0.01). A strong correlation between bacterioplankton and virioplankton was detected (P<0.01), indicating that bacterioplankton is probably the main host of virioplankton, and the virioplankton probably mainly existed in the form of bacteriophage. Relationships between organic carbon and bacterioplankton need to be further studied in order to illuminate growth and decline mechanism of microbes in SCS.
  • DownLoad:Ecological distribution of bacterioplankton and virioplankton in the north of South China Sea in spring.PDF
  • High throughput sequencing analysis of bacterial communities in soils of a typical Poyang Lake wetland
  • Authors:WANG Peng, CHEN Bo and ZHANG Hua
  • Abstract:Bacterial communities are crucial for the functioning of wetlands as they play a critical role in energy flows and nutrient transformation. Poyang Lake, the largest freshwater lake in China, forms a large area of wetland due to its great changes in seasonal water levels, which play an important ecological role in the middle and lower reaches of Yangtze River. In this study, surface soils (0-10 cm) covered with typical plants were sampled at five sites from the lake surface to a sloping field in Poyang Lake wetland in November 2014. Chemical parameters measured in the soil included NH4+-N, NO3--N, TN, TP, and SOC. We profiled the bacterial community structure by sequencing the V3-V4 16S rRNA gene on the Illumina Miseq PE300, using 338F (5'-ACTCCTACGGGAGGCAGCA-3') and 806R (5'-GGACTACHVGGGTWTCTAAT-3') primers. A total of 134,223 bacterial sequences were obtained, and a similarity of 97% was used to identify operational taxonomic units (OTUs), which resulted in a total of 2,072. The phylogenetic affiliation of each 16S rRNA gene sequence was analyzed by an RDP Classifier against the Silva 16S rRNA database. The coverage of all soils was over 99%, indicating a deep sequencing. The bacterial community richness calculated by the Chao1 estimator and the bacterial community diversity calculated by the Shannon index showed the same trend among the five soils covered with different plants:Carex soil > Carex-Phalaris soil > Phragmites soil > mud flat soil > Artemisia soil. The principal component analysis of OTUs showed that the bacterial community structure was more similar among soils that were closer along the transition from the lake surface to the sloping field. The bacterial community structure was similar among Carex-Phalaris soil, Carex soil, and Phragmites soil, but very different between mud flat soil and Artemisia soil. Proteobacteria (30.0% of total sequences) was the most abundant phylum in Poyang Lake wetland, mainly including Alphaproteobacteria (7.2%), Betaproteobacteria (8.9%), Deltaproteobacteria (10.5%), and Gammaproteobacteria (2.8%). Except for Proteobacteria, other phyla with high abundance were Acidobacteria (16.7%), Chloroflexi (16.5%), Nitrospirae (10.2%), Firmicutes (7.5%), Actinobacteria (4.8%), Gemmatimonadetes (3.8%), and Chlorobi (1.8%). Proteobacteria was the most abundant phylum in Carex, Carex-Phalaris, and Phragmites soils, and the third most abundant phylum in mud flat and Artemisia soils, after Chloroflexi and Nitrospirae (first abundant phylum in mud flat and Artemisia soils, respectively), and Acidobacteria and Chloroflexi (second abundant phylum in mud flat and Artemisia soils, respectively). Most of the phyla's relative abundance had an obvious trend along the transition from the lake surface to the sloping field. Nitrospira (10.2%) was the most abundant genus in this area, and the Nitrospirae abundance was much higher than that in other wetland soils, reflecting the importance of the nitrogen cycle in the ecological system of Poyang Lake wetland. There were many norank or uncultured genera, making it difficult to study their ecological functions. Redundancy analysis of bacterial phyla and chemical parameters in soil showed that TP, NH4+-N, and SOC had more relevance to the bacterial community structure. The results of this study showed that there were differences in bacterial community structure among soils covered with different plants in the Poyang Lake wetland, and these differences had regular variation along the transition from the lake surface to the sloping field.
  • DownLoad:High throughput sequencing analysis of bacterial communities in soils of a typical Poyang Lake wetland.PDF
  • Effects of Helianthus annuus varieties on rhizosphere soil enzyme activities and microbial community functional diversity of saline-alkali land in Xinjiang
  • Authors:ZHANG Xulong, MA Miao, WU Zhenzhen, ZHANG Zhizheng, GAO Rui and SHI Lingyu
  • Abstract:To select the most suitable Helianthus annuus variety for improving the soil quality of saline-alkali in Xinjiang, a pot experiment was carried out to study the effects of four H. annuus varieties (Xinkui 4, Xinkui 6, Xinkui 10, and Aidatou) on the physical and chemical property, enzyme activity, and functional diversity of microbial community in rhizosphere saline-alkali soil. The research draws the following conclutions:Xinkui 6 can significantly (P<0.05) reduce the pH of rhizosphere soil and increase its total nitrogen content as well as the activity of invertase. Xinkui 4 can significantly increase the available nitrogen content of rhizosphere soil, the content of rapid available phosphorus and potassium and the activity of urease and phosphatase. The four varieties of H. annuus can significantly increase the average well color development (AWCD) (72 h, P < 0.05) of 31carbon sources for rhizosphere soil microbes in saline-alkali land, and presenting the following order:Xinkui 4 > Xinkui 6 > Xinkui 10 > Aidatou > control (CK). The four varieties of H. annuus planted in saline-alkali soil improve the Shannon diversity index (H), simpson's dominance (D) and substrate richness (S) of soil microbial community, respectively, and presenting the similar rule:the diversity indices of rhizosphere soil microbial for Xinkui 4 are the highest, which are significantly higher than the lowest CK. A principal component analysis shows that the community composition of soil microbes can be improved by planting H. annuus. The major carbon sources utilized by saline-alkali soil microbes are carbohydrates, amino acids, carboxylic acids and polymers. Therefore, planting H. annuus, especially the variety of Xinkui 4, can significantly increase physical and chemical property of soil, enzyme activity and improve the functional diversity of rhizosphere soil microbes in saline-alkali land, coupled with the optimization of community structure in saline-alkali soil microbes.
  • DownLoad:Effects of Helianthus annuus varieties on rhizosphere soil enzyme activities and microbial community functional diversity of saline-alkali land in Xinjiang.PDF
  • Characteristics of microbial community in forest soil between rhizosphere and non-rhizosphere in summer and autumn in Qinling Mountains, China
  • Authors:CAO Yongchang, YANG Rui, LIU Shuai, WANG Ziquan, HE Wenxiang and GENG Zengchao
  • Abstract:This study focused primarily on the biodiversity of microbial communities in soil between the rhizosphere and non-rhizosphere in summer and autumn among four types of common trees-the Tooth Oak (Quercus aliena var. acutidentata), Chinese pine (Pinus tabuliformis), armand pine (Pinus armandii) and spruce (Picea asperata)-on the Qinling Mountain, China, using the micro BIOLOG method. We found that:(1) The Average Well Color Development (AWCD) of the soil in the rhizosphere was significantly different from that in the non-rhizosphere in most of the seasons, with AWCD in the non-rhizosphere being higher than that in the rhizosphere, except for the soil where spruce was grown in autumn. (2) Biodiversity of microbial communities differed remarkably between rhizosphere and non-rhizosphere in the soil where the four different types of trees were grown in either summer or autumn. For soil where tooth oak was grown, the biodiversity of microbes in the rhizosphere was lower than that of the non-rhizosphere in both summer and autumn, and both these values were in lower in summer than in autumn. While the biodiversity of microbes in soil among the other three coniferous trees showed similar trends to that of tooth oak in summer, they exhibited the reverse of this trend in autumn. Furthermore, the biodiversity of these soils in autumn was lower than that in summer in the non-rhizosphere but higher in the rhizosphere. (3) The results of principal component analysis indicated that the biodiversity of microbial communities in the soil for these four types of trees was significantly different, and the principal component scores for biodiversity among the four studied species in either the rhizosphere or non-rhizosphere in different seasons also varied substantially. The highest score among all studied species was found in the non-rhizosphere of the soil where tooth oak grew, followed by that of armand pine, and spruce, with that of Chinese pine being the least. The principal component score for the soil in the rhizosphere varied with season-in summer, the score was relatively high for Chinese pine and armand pine and lower for spruce. In autumn, the score was relatively high for Chinese pine and spruce and lower for tooth oak. The correlation between the comprehensive score and biodiversity index in all cases was positive or extremely positive. (4) Redundancy analysis showed that the combined effects of soil properties have a significant impact on the biodiversity of microbial communities in the soil.
  • DownLoad:Characteristics of microbial community in forest soil between rhizosphere and non-rhizosphere in summer and autumn in Qinling Mountains, China.PDF
  • Distribution characteristics of soil macro-faunal communities along a latitudinal gradient in farmland of Heilongjiang Province
  • Authors:CAO Yang, GAO Meixiang, ZHANG Xueping and DONG Chengxu
  • Abstract:Spatial patterns of soil faunal communities at a regional scale are important foundations for the maintenance and protection of belowground biodiversity. Although many studies have addressed the spatial patterns of soil animal communities in different habitats, few have focused on the spatial patterns along latitudinal gradients. In this study, we determined the composition, horizontal structure, vertical structure, and diversity characteristics of soil macrofaunal communities in farmland systems along a latitudinal gradient. We selected three representative mountain areas along the latitudinal gradient:the Maoer Mountains (Maoer Mountain ecosystem station, 45°20'-45°25'N, 127°30'-127°34'E), the Xiaoxing'an Mountains (Dailing,47°10'-47°14'N, 128°53'-128°55'E), and the Da Hinggan Mountains (Tahe, 52°09'-53°23'N,123°19'-125°48'E). In each study area, three farmlands at least 50 m apart with similar conditions were randomly selected. In each farmland, four plots (5 m×5 m) were randomly delineated. In each plot, four soil profiles (50 cm×50 cm) were randomly collected and divided equally into three 5 cm strata to survey the soil macrofaunal communities. The hand picking method of separation was used to determine the soil macrofaunal communities. Fieldwork was conducted in August 2011. Using bivariate related analysis and canonical correspondence analysis, we assessed the relationships between soil animal communities and environmental factors. In total, 2339 individuals from 35 groups of soil animals were collected, which belonged to 2 phyla, 6 classes, 14 orders, and 35 families. Enchytraeidae, Lumbricidae, Carabidae, and Staphylinidae were dominant families, accounting for 58.84% of the total number of individuals. Formicidae, Araneidae, and Geophilomorpha were common groups, accounting for 32.79% of the total number of individuals. The results showed that:(1) In terms of horizontal distribution, individual density and richness (i.e. numbers of groups) at sites followed the order Maoer Mountain > Dailing > Tahe. Results of the one-way ANOVA revealed there were no significant differences in individual density or richness in the soil macrofaunal communities at different latitudes. The Shannon-Wiener diversity index (H) and Pielou evenness index (E) for sites followed the order Maoer Mountain > Dailing > Tahe. The Simpson dominance index (C) of Tahe and Dailing were higher than that of the Maoer Mountains, and the Margalef richness index (D) was greatest in Tahe, followed by the Maoer Mountains and Dailing. (2) In terms of vertical distribution, no significant differences were detected among the three different latitudinal areas for individual density or richness at the same vertical level (P < 0.05). Individual density and richness in soil macrofaunal communities decreased with increasing soil depth, except for soil macrofaunal communities from the Maoer Mountains at 5-10 cm, indicating an obvious surface aggregation. (3) Regarding the relationships between soil macrofaunal communities and soil environmental factors, the bivariate correlation analysis showed there were no significant correlations among richness, individual densities, diversity indices, evenness indices, richness indices, pH values, organic matter, total nitrogen, total phosphorus, and available phosphorus. Results of canonical correspondence analysis further indicated that the dominant and common groups were highly adaptable to environmental factors and the dominant and common groups were widely distributed in the three latitudinal areas. This study showed that the numbers of groups, individual densities, and diversity indices of the soil macrofaunal communities from the farmland ecosystem changed along a latitudinal gradient, but no significant changes were found in this study. Different soil animal groups at different latitudes are affected by environment variables. At the local scale, the influence of environmental factors on soil macrofauna should not be ignored. The results of the study create a foundation for researching spatial patterns and mechanisms of biodiversity maintenance at regional scales.
  • DownLoad:Distribution characteristics of soil macro-faunal communities along a latitudinal gradient in farmland of Heilongjiang Province.PDF
  • Adaptation needs of farmers to climate change in an ecologically vulnerable alpine region: take Gannan Plateau for example
  • Authors:ZHANG Qin, ZHAO Xueyan, WANG Yaru, LUO Li and XUE Bing
  • Abstract:The impacts of climate change on the people who serving the natural resources as a livelihood is particularly significant. To define the adaptation demands of farmers to climate change is very important to develop effectively adaptation policies for climate change, and to enhance the farmers' adaptability to climate change. This paper, based on 500 questionnaires, analysis of the adaptation demands of the different regions and different livelihood strategies of farmers in Gannan plateau, and the key factors of affecting the adaptation demands of the farmers by using the two logistic regression model. The results show that:(1) In the process of adaptation to climate change, the infrastructure demands of farmers in Gannan plateau is the most intense, and secondly are both of the demands of information and production technology. (2) There are different demands in adaptation to climate change in different regions, of which, both of the demands of the farmers of pastoral area and farming district for infrastructure are the strongest, and the demands of agricultural-pastoral area for information is the most intense. (3) Different livelihood strategies of farmers to climate change have different demands, of which, the demands of typeⅠhouseholds(with less than 10% of their income from non-farm) for credit insurance is the most intense, the demands of type Ⅱ households (with 10% to 50% of their income from non-farm) and type Ⅲ(with more than 50% of their income from non-farm) households for infrastructure are the most strong; (4) In addition, the natural capital and the physical capital are the key factors that affect farmers' demands for the production technology, the natural capital and the human capital are the key factors that influence farmers' demands for information, the human capital and the financial capital are the key factors that impact farmers' demands for infrastructure, and the natural capital, human capital, financial capital, material capital and the social capital are the key factors that affecting farmers' demands for credit insurance. Finally, the policy suggestions to improve the farmers' adaptation to climate change are proposed.
  • DownLoad:Adaptation needs of farmers to climate change in an ecologically vulnerable alpine region: take Gannan Plateau for example.PDF
  • The nitrogen footprint of different scales of restaurant food waste: a Beijing case study
  • Authors:ZHANG Dan, LUN Fei, CHENG Shengkui, LIU Xiaojie, CAO Xiaochang and LIU Zixin
  • Abstract:Recently, research on food loss and waste and the related environmental impact has increased globally. Wasted food creates nitrogen emissions throughout the food supply chain, from agricultural production and food processing to consumption and waste disposal. Although the generation of food waste must be reduced, the lack of quantitative information on the production of household and catering food waste has led to an underestimation of waste volumes and inhibited the development of sufficient policy interventions designed to decrease food waste. The present study investigated the volume of catering food waste generated in Beijing and calculated its nitrogen footprint. In the present study, we focused on avoidable food waste, i.e., all wasted food and raw materials that could have been consumed had they been prepared differently. Other bio-wastes, such as vegetable peels, bean dregs, or bones, were not measured. During first-hand surveys of the catering sector of urban Beijing in 2013, 136 restaurants were studied. These establishments were divided into large, medium, small, canteen, and fast-food restaurant categories. A total of 2,704 samples were collected, each consisting of two parts:a consumer questionnaire and the weight of the sample of food waste generated by consumers of the establishment. Then, the nitrogen footprint and its discharge to the environment were calculated. The main conclusions of the present study are:(i) an estimated 74.39 g of food waste is produced per non-household meal in urban Beijing. Food waste generation differed significantly among restaurant types. For example, large restaurants generated the most waste-99.34 g, three times that produced by fast food restaurants (30.27 g). (ii) The food waste comprised many different food types, the most prominent (by weight) being vegetables (44.18%), followed by aquatic products (12.04%), pork (8.60%), beans and bean products (7.69%), poultry (7.50%),wheat flour (6.96%), rice (5.36%), beef (1.90%),mutton (1.89%), other meat (1.22%), eggs (1.20%), nuts (0.97%), other grains (0.24%), fruits (0.20%), and dairy products (less than 0.1%). (iii) The total N discharge to the environment was 16.37 per non-household meal, and the nitrogen footprint of the catering food waste produced per non-household meal in Beijing was 0.22 g N/g. By food category, the largest proportion of the calculated nitrogen emissions was generated by meat (30.65%), beans and bean products (26.61%), and grains (12.90%). By process, the food production stages producing the largest proportions of the emissions were agricultural production (almost 85%), waste management (7.60%), and fertilizer production (37.39%). Nitrogen discharge to the atmosphere, soil, and water was 7.34, 1.34, and 7.69 g per non-household meal, respectively. (iv) For the waste volumes, large restaurants generated the most N discharge-22.53 g three times that produced by fast food restaurants (5.67 g), followed by the medium (18.05 g) and small (13.05 g) restaurants.
  • DownLoad:The nitrogen footprint of different scales of restaurant food waste: a Beijing case study.PDF
  • Ecological assessment of the oyster Crassostrea sikamea population and associated benthic communities on restored oyster reefs along Jiangsu Province coast, China
  • Authors:QUAN Weimin, FENG Mei, ZHOU Zhenxing, WU Zuli, TANG Fenghua, WANG Yunlong, BAO Xiaosong, SHEN Hui and CHENG Wei
  • Abstract:Oyster reefs are an important coastal habitat providing essential ecosystem services, including water filtration, habitat provisioning, shoreline stabilization, and nutrient retention. The Liyashan oyster reef is located inshore of Dongzhao Port, Haimen County, Jiangsu Province, China. However, the natural intertidal oyster reef is rapidly degrading due to high sedimentation, habitat loss, and overfishing, with its area reduced by 30% during 2003-2013. To protect the important biogenic reef, a restoration project was initiated in 2013-2014. We recycled 100 tons of oyster shells (≥ 6 months) from the oyster aquaculture zone in Xiangshan Bay as substrate (cultch) for oyster larval setting, where 16000 nylon bags (diameter:20 cm, height:50 cm, mesh:2 cm) were filled with old oyster shells. In early July 2013, the oyster shells were placed in the Liyashan waters, creating a habitat for young oysters to attach and grow to ensure their abundance. We constructed 53 small reefs (24 single-layer reefs[SLR] and 29 multi-layer reefs[MLR]) at five restoration sites within the Liyashan area. Oyster abundance was significantly higher in MLR than in SLR at each of the four sampling periods, but showed a significant decline with reef development. The mean shell height of oysters in the restored reef significantly increased during two periods (from September to November 2013, and March to May 2014) (Kruskal-Wallis test, Q=10.519,Q=6.527,P<0.05), but oysters stopped growing in the overwintering period (Nov 2013 to March 2014) (Q=0.35,P>0.05). Forty-one species of resident benthic macrofauna were recorded at the restored reefs. Although there were few changes in species richness, the mean density and biomass showed significant increases with reef development that were similar to the adjacent natural oyster reef, but significantly higher than at the non-restored zone. The mean total density and biomass of benthic communities were 5.1 and 3.1 times higher, respectively, at restored than at non-restored reefs.MDS plots showed that resident benthic communities differed significantly between the restored and adjacent natural reefs (ANOSIM, P=0.001), which were mainly attributed to higher densities of sipunculid worms (Phascolosoma esculenta), rock snails (Thais luteostoma), polychaete worms (Perinereis nuntia), and Asian shore crabs (Hemigrapsus sinensis). Oyster reef restoration in Jiangsu Province was considered to be successful, improving the oyster population, reef area and density, and biomass of resident macrofauna.
  • DownLoad:Ecological assessment of the oyster Crassostrea sikamea population and associated benthic communities on restored oyster reefs along Jiangsu Province coast, China.PDF
  • Assessment of ecosystem food production and its spatiotemporal heterogeneity in the Bailong River Watershed, Gansu
  • Authors:XIE Yuchu, GONG Jie, QI Shanshan, ZHANG Ying and GUO Jianjun
  • Abstract:Terrestrial ecosystems function supply food (e.g. grains, vegetables), maintain diversity, and prevent environmental contamination. Thus, it is important to human well-being. Food production is vital for the sustainable development of human populations, and its dynamic spatiotemporal factors are closely related to spatial geographical heterogeneity and social development. However, there are only a few studies on the universal dynamic evaluation methods for ecosystem function used at the regional scale, especially in the fragile mountains of China. Bailong River Watershed (BRW) is located in the transitional ecotone along the Tibet Plateau, Loess Plateau and Qinba Mountains, and it was selected to analyze the spatiotemporal heterogeneity of ecosystem food production. Based on a field survey employing land use data, model simulations, and GIS spatial analysis, the ecological conditions and socio-economical factors were used to revise the previously held dogma which put forward by Costanza in 1997. Specifically, sources of hazards reflected the differences in ecological conditions. The resource scarcity theory and the willingness to pay were used to revise and calculate the economic developmental coefficient. A dynamic evaluation model was constructed with the above corrections method and applied for ecosystem food production services assessment in the Bailong river watershed during 1990-2010. In addition, spatiotemporal heterogeneity and food production were analyzed by ArcGIS 9.3. The results indicated that the supply of cropland distributed in the river valley and bank area of BRW, hill slopes, low mountain regions and decreased. The area of instable cropland and the index of social progress increased. In the period of 1990-2010, ecosystem food production value increased. The mean value of food production was 1.8674 million Yuan in 2010. In addition, the spatial distribution pattern change of food production value was not obvious. Land accounting for high yield of food production value was 42.4% of the total area, which was mainly distributed in the valleys of BRW between Zhouqu and Hanwang town, the northwestern part of Tanchang County. The low-yield areas of food production distributed in the national nature reserve and forest. Our data change how the value of China's terrestrial ecosystem was previously defined on a national to regional scale. Compared with a previous evaluation model, the change in food production was smaller using our method, and its spatial pattern was a better fit to the natural system of the Bailong river watershed. These data indicate that natural hazards (such as landslides and debris) and human activities affected food production and its value.
  • DownLoad:Assessment of ecosystem food production and its spatiotemporal heterogeneity in the Bailong River Watershed, Gansu.PDF
  • Evaluation of the structural elements of Qingdao ecological network based on the CL-PIOP method
  • Authors:FU Qiang and GU Chaolin
  • Abstract:The analysis of ecological networks in landscape ecology has been accepted increasingly by a growing number of institutions and scholars worldwide. The network connections of structural landscape elements, such as patches and corridors, enhance the effective flow of matter, energy, and information. Furthermore, the network structure can guarantee stability of the ecological network when certain ecological patches or corridors disappear. The ecological network therefore has some flexibility in the layout and adjustment of its spatial structure. This makes it possible to provide compromises for the spatial contradiction between protection of ecosystems and the socio-economic development that accompanies the current rapid urbanization in China. Quantitative evaluations of the structure elements of ecological networks play a key role in the protection, restoration, and adjustment of the regional environment. The related evaluation indexes from graph theory provide methods for such a quantitative evaluation. We intended to identify the patches and corridors that have a large influence on the connectivity of an ecological network, based on data evaluated by indexes from graph theory. Taking Qingdao City as an example, our study constructed wetland and woodland ecological networks, and classified these ecological networks by a certain threshold. This created a series of ecological networks of these two ecosystems with different connection strengths. We proposed two standards (Standard I and Standard II) to analyze the data produced by the evaluation index CL-PIOP (Correlation Length-Percentage of Importance of Omitted Patches). Our results show that:Standard I can determine the importance of patches and corridors in ecological networks of a certain connection strength. Standard I can also subdivide the important patches and corridors by the statistics of the importance of each connection strength. The most important patches based on standard I overlapped with almost all the larger patches when they were ranked by size. This shows that patch area or other properties cannot be used as the sole criterion for evaluating the maintenance of regional ecosystems. It also indicates some patches with a smaller area should receive more attention, because they may play a fundamental role in the overall connectivity of the ecological network. In addition, standard II can identify the critical patches and corridors that can connect two sub-networks of a certain connection strength by analyzing the patches and corridors with abnormal large CL-PIOP values at a set connection strength. Furthermore, the critical patches recognized by standard II are not prominent in their own properties (e.g., their areas are not large), and the corridors may not stand out from the numerous corridors that differ little, so are therefor hard to identify with other conventional methods. Overall, our study explored the application of evaluation indexes from graph theory to evaluate an ecosystem within the framework of ecological networks. Furthermore, our study proposed two standards to determine the important patches and corridors rapidly, which can provide a quantitative database for regional ecological land evaluation, planning, protection, and restoration.
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  • Adaptive eco-economic regionalization model and its application
  • Authors:XU Chongqi, LI Feng, HAN Baolong and TAO Yu
  • Abstract:Achieving sustainable urban development during rapid urbanization is one of the important issues worldwide. Eco-economic regionalization (EER) is a complex regionalization method for dividing urban regions into different eco-economic functional zones by considering a wide range of local environmental (water-heat condition, biodiversity, vegetation coverage rate, etc.) and socio-economic (gross domestic product (GDP), population density, human activity pressure, road network density, etc.) factors. Urban and regional planning based on EER might be beneficial for local environmental protection, as well as sustainable economic growth. Previous studies have investigated the principles, methods, and index system for EER application. However, improving the accuracy and dynamic adaptability of EER is essential in order to ensure its application to small urban regions. In this study, the EER approach was modified by simulating population density in urban areas of Zengcheng District, Guangzhou, and an adaptive regionalization model was developed using remote sensing (RS) and geographical information system (GIS) techniques. Improving the accuracy of raw input data for calculating the indices is important to ensure the accuracy of the EER results. Previously, population density was aggregated on an administrative regional basis, whereas, in this study, we estimated population density grid by grid within the built-up area of Zengcheng District by linear modeling of the gray value in each pixel from the Defense Meteorological Satellite Program/Operational Linescan System nighttime light data. According to the linear model, the total number aggregated from all these pixels was equal to the statistical population in each administrative region by assuming that nobody lives outside the built-up area. Further, an Adaptive Eco-economic Regionalization model (AEER) was developed for Zengcheng District in order to enhance the dynamic adaptability of the EER approach. In our AEER model, the study area was first divided into four zones-ecological conservation zone, ecological priority zone, development optimization zone, and key development zone-allowing the comparison of EER results across various case study areas. Next, the area and location of each of the four zones were determined by introducing six parameters into the AEER model so that the results could be more adaptive to local management objectives. Further, two scenarios were developed for the application of this AEER model in Zengcheng District. Our results indicated that the AEER model yields highly accurate zoning results that are more adaptive to the local context. Therefore, this model might be a powerful tool for urban and regional EER applications in other city areas. Further, three perspectives have been proposed on improving the current EER model:(1) Producing spatially explicit input data for index estimation (such as GDP and available resources, both of which are normally aggregated on administrative regional basis) is the key to improving the accuracy of the zoning results. (2) The results from the EER model are only useful when the zoning process is more adaptive to local management objectives. (3) The zoning results should be presented for each administrative region in order to obtain strong policy implications; further, they should be presented grid by grid so that the vital ecological processes can be better preserved based on this EER approach.
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