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Volume 38,Issue 21
  • Research advances in nighttime sap flow density, its physiological implications, and influencing factors in plants
  • Authors:FANG Weiwei, LÜ Nan and FU Bojie
  • Abstract:Nighttime sap flow is the night-time movement of fluid within the sapwood of root, stem, or branch of a plant. There is increasing evidence of occurrence of nighttime sap flow in a range of species, habitats, and ecosystems. In this study, we elucidated the magnitude of nighttime sap flow density and summarized the state of research in this field from the perspective of physiological implications, influencing factors, and the eco-hydrological effects. Generally, nighttime sap flow density is 5%-20% of that at daytime. Nighttime sap flow involves stem refilling and transpiration processes, yet there are only a few studies or techniques to distinguish them. Although the fraction of nighttime sap flow to daytime sap flow is low, the processes of stem refilling and transpiration have significant implications on the growth and survival of plants. The process of stem refilling is beneficial for plants as it increases stem water potential, repairs embolized xylem conduits, and promotes the adaptability of plants to drought stress. Furthermore, the process of transpiration is related to nutrient availability, oxygen transport, and hydraulic lift in plants. The factors controlling nighttime sap flow may have considerable complexity. In addition to the habitat and genetic factors of a plant, the magnitude of nighttime sap flow is mainly affected by meteorological factors. The influence of soil moisture on nighttime sap flow is related to the habitat conditions. Nighttime sap flow also has significant implications on water budgets and hydrological processes at different scales because of water loss at night. Future studies should focus on 1) exploring the relationship between nighttime sap flow and physiological characteristics under different habitat conditions; and 2) quantitatively assessing the effects of nighttime sap flow on hydrological processes, and (3) analyzing the response of nighttime sap flow to global climate change.
  • DownLoad:Research advances in nighttime sap flow density, its physiological implications, and influencing factors in plants.PDF
  • Personality traits and their relationships with musk secretion by captive alpine musk deer (Moschus sifanicus)
  • Authors:ZHOU Yang, SUN Taifu, LI Yong, ZHOU Mi and MENG Xiuxiang
  • Abstract:The alpine musk deer (Moschus sifanicus) is an endangered ungulate for which captive breeding is being promoted as the best way to conserve the species. Studies of animal personality could be an important path to facilitate captive breeding practices, yet only a few studies have been carried out in this field for musk deer. Focal sampling and scan sampling were used to quantify personality traits (measured by activity, territoriality, stereotypy, exploration, and behavioral redundancy) of alpine musk deer at the Breeding Center for Alpine Musk Deer, Xinglongshan National Nature Reserve, Gansu Province, and to investigate the effects of the captive musk deer's personality traits on musk secretion. We also assessed the relationships between personality traits and both gender and age during both mating and non-mating seasons. We found that older individuals were less active during both mating and non-mating seasons, and were less territorial during non-mating season (all P < 0.05). Females were more active than males (P < 0.05). Alpine musk deer were more active and territorial during mating season than during non-mating season, and activity and territoriality were positively correlated in both seasons (P < 0.05). Males with higher activity and territoriality had more musk secretion (P < 0.05). Our results showed that personality traits of musk deer varied between age and gender, but there was consistency across mating and non-mating seasons. Personality traits, especially activity and territoriality, can predict the musk secretion by males. Quantitative analysis of musk deer personality is an appropriate approach for the development of musk resources.
  • DownLoad:Personality traits and their relationships with musk secretion by captive alpine musk deer (Moschus sifanicus).PDF
  • A study on the suitable time window of feeding vegetation fit for overwintering geese in Poyang Lake
  • Authors:MENG Zhujian, XIA Shaoxia, YU Xiubo, RAO Didi and JIN Binsong
  • Abstract:Geese are the dominant species among waterbirds overwintering along the middle and lower Yangtze River who prefer Carex spp as their main food source. As the largest freshwater lakes connected to the Yangtze River, the consequent growth of the wetland vegetation at Poyang Lake is greatly affected by hydrological factors which may determine the exposure time of the meadow and as well as the effective growth time of wetland vegetation. However, geese are of highly selectivity of food, Carex spp is just suitable during a specific growing period and plant height is one of the important selection factors. Clarifying the relationship between feeding characteristics of geese and the growth process of Carex spp is therefore significant to determine the spatial-temporal pattern of suitable habitats for geese conservation. Taking Changhuchi Lake, a typical sub-lake of Poyang Lake National Nature Reserve, as the study area, this study undertook in-situ experiments as well as lab analysis of Carex spp during the spring growth season (from early March to early May), including 12 field surveys of plant height and 7 field surveys of aboveground biomass along four elevation gradients. Data extracted from remote sensing interpretation, meteorological data and field survey data were combined to identify the flood recession dates as well as the effective growth time of different elevation gradients. By incorporating Logistic equation and the feeding characteristics of geese, the time window fit for geese's feeding on vegetation was reversely deduced from growth curve model. The results showed that there was a significant positive correlation between plant height and aboveground biomass and both of them fit the Logistic growth model; hydrological regime and temperature jointly affected the growing process of Carex spp. Delayed flood recession will influence the vegetation pattern for geese to feed on due to the low temperature limit. When the exposure time of Carex spp reached 12-28 days in autumn and 83-182 days in spring, they provided an appropriate time window for geese to feed. Our study proposed a method to determine the time window of Carex spp fit for overwintering geese and analyzed the influencing mechanism for hydrological factors on wintering geese's food availability. It was evidenced that a 20-day delay of flood recession would cause a great mismatching between the growth patterns of Carex spp and the foraging requirements of wintering geese in their peak period through our field monitoring. This study is of great contribution to the hydrological regulation and management of Poyang Lake wetland.
  • DownLoad:A study on the suitable time window of feeding vegetation fit for overwintering geese in Poyang Lake.PDF
  • Investigation into roosting ecology of Myotis altarium
  • Authors:GONG Xiaoyan, HUANG Taifu, WU Tao, ZHANG Youxiang, PENG Qingzhong and LIU Zhixiao
  • Abstract:Myotis altarium is a typical cave-dwelling and quasi-endemic bat species (Vespertilionidae Chiroptera) in China. We investigated the roostpoint distribution, roosting behavior, body temperature, roost-site temperature, and the safety of the bats in the karst caves of Xiangxi Tujia and Miao Nationality Autonomous Prefecture, in the Hunan province, in recent years. On the basis of a total of 361 individual-by-times observed, the results indicated that their roost-points were distributed relatively, gathered within a 200 m distance of the cave tunnels from the entrances, and usually 2-6 m from the ground. Approximately 74% individual-by-times took on an upside-down roosting-posture with their abdomens clinging to the cave wall. The range of body temperature in the years was 3.57-20.25℃. Their body temperature was always slightly higher than the temperature of roost-sites, but there were no significant differences between them (P > 0.05). However, there were significant differences in body temperature and roost-site temperature in different months (P < 0.05). By a comprehensive evaluation of the roosting safety of these bats, we identified 60.1% individual-by-times as "high safety", whereas 22.7% and 17.2% were "medium safety" and "low safety", respectively. To conserve vulnerable species, it would be beneficial to strengthen biodiversity and cave biology education, which can enhance the conservation awareness and practices of bat species and cave resources for local people.
  • DownLoad:Investigation into roosting ecology of Myotis altarium.PDF
  • Community structure and butterfly diversity in different habitat types in the Qinghai Yushu plateau
  • Authors:DAN Zhicuo, BAO Min, MA Cunxin, LI Leilei, HAO Huiwen, CHENG Fan, CAI Xiangzhuoma and CHEN Zhenning
  • Abstract:From May to August in 2016 and 2017, we selected five habitats (forest, shrub, alpine shrub, alpine meadow, and bare rock) to investigate butterfly species and community diversity in Yushu City. A total of 1580 individuals were recorded, belonging to 62 species of 7 families and 40 generas. There were 19 species of Palaearctic realm, 2 of Oriental realm, and 41 widespread species; those accounted for 30%, 3%, and 67% of the total respectively. Nymphalidae with the most individuals (535) was the dominant family, accounting for 34% of the total. The butterfly diversity index (H'), dominance index (D), species richness index (R), evenness index (J), and similarity index (I) were calculated and analyzed for the five habitats. The results showed that shrub habitat had the highest diversity index, high evenness index, and high species richness index, but the dominance index was the lowest; the alpine meadow habitat had the lowest diversity index, specific richness index, and evenness index, but the dominance index was the highest.
  • DownLoad:Community structure and butterfly diversity in different habitat types in the Qinghai Yushu plateau.PDF
  • Economic evaluation of key protected fauna and flora species in China
  • Authors:XIE Shilin, SHI Xuewei, PENG Wenjia, XIAO Hui, OUYANG Zhiyun and XIAO Yi
  • Abstract:We assessed the economic value of key protected species of wild fauna and flora based on the contingent valuation method. In total, 5500 questionnaires were collected, of which 4672 were valid. Analysis of the valid questionnaires showed that the gross willingness to pay (WTP) was 209 yuan person-1 a-1, with fauna being 111.37 yuan person-1 a-1 and flora being 97.65 yuan person-1 a-1. The WTP was significantly different between different protection levels. Based on the national urban employment data of 2016, the gross value of all endangered species was 18.29×103 billion yuan/a, with fauna being 8.20×103 billion yuan/a and flora being 10.09×103 billion yuan/a. Our analysis showed that economic income, education degree, knowledge, and interest in endangered species, and whether once participated in the activities aimed at endangered species' conservation are important factors that influence WTP.
  • DownLoad:Economic evaluation of key protected fauna and flora species in China.PDF
  • The evolvement of land use patterns in coastal cities and its influence on ecosystem service values
  • Authors:ZHANG Tianhai, TIAN Ye, XU Shu, TANG Lina and GUO Wei
  • Abstract:Land use change alters the original ecosystem service values (ESV) and function of land, related toregional sustainable development. This research chose the coastal city of Xiamen as a study area, using land use data and related literature data on three phases, 1989, 2000, and 2010, the transfer matrix method, the indexes of ESV and land use dynamic degree, and calculated and analyzed the land use change in Xiamen City and its effects on ESV. The results showed that the land use dynamic degree (LUDD) in Xiamen was more than five times the national level during the same period of 1989-2010. In this period, both the dynamic degree of built-up land in Xiamen City and entire nation were higher than other types of land use. Between 2000 and 2010, Xiamen's LUDD was nearly five times (458.94%) that of between 1989 and 2010. Furthermore, the built-up land net change and dynamic degree in both Xiamen and the entire nation were as times as those in 1989-2000, much higher than that of other land use types. In comparison with the LUDD for Xiamen City and three other coastal areas, the built-up land was also higher than other land use types. Additionally, Xiamen's dynamic degree of built up land ranked higher than that of Zhejiang Coast > Xiamen > Fujian Coast > Jiangsu Coast. Regarding the spatial patterns, the increase of the built-up land in Xiamen was mainly by the landfills of watersheds and occupied the farmland around the coastal zone. Forest land remained steady in the northern area.During the period of 1989-2010, the ESV in Xiamen was consistently in decline, of which the total decreasedamount of ESV in 2000-2010 (120 million Chinese Yuan) was more than 10 times (1382.57%) of that (RMB 10 million) in 1989-2000. Because of the large area reduction in water and farmland, the ecosystem service functions, such as water conservation and waste disposal tended to be weakened, resulting in many ESV components decreasing in the entire period from 1989 to 2010. The largest decline was hydrologic regulation and waste disposal, with minimal changes in food and raw material production. During the 1989-2000 stage, the ESV change in soil protection contributed the most, whereas in the 2000-2010 stage, the ESV change in the hydrological regulation made the biggest contribution. In 2010, the ESV per km2 of Xiamen was ranked at a low level in the eastern coastal areas. Looking back on its high LUDD in 2000-2010, it indicated that Xiamen needed to define an ecological redline for strict protectionon keyecological functional zones, especially for watersheds and forest land in the northern area.
  • DownLoad:The evolvement of land use patterns in coastal cities and its influence on ecosystem service values.PDF
  • Analysison trade-offs and synergistic relationships among multiple ecosystem services in the Shiyang River Basin
  • Authors:WANG Bei, ZHAO Jun and HU Xiufang
  • Abstract:The research on the interactions among multiple ecosystem services is a hot topic in the field of international ecology and geography. The Shiyang River Basin, a typical representative of an arid inland river basin, was used as an example. Several models based on InVEST were used to estimate the value of five key ecosystem services from 2005 to 2015, including water conservation, soil conservation, nutrient retention, carbon storage, and biodiversity. Spatial-temporal differentiation of ecosystem services were also analyzed. In addition, we quantitatively assessed the spatial patterns of interactions among different ecosystem services by applying the partial correlation analysis at a pixel scale. The results were as follows:(1) These ecosystem services presented spatially differential characteristics; the spatial pattern of water conservation, soil conservation, carbon storage, and biodiversity presented the characteristic of having a "low-value zone located at the northeast, whereas there was a high-value zone distributed mostly in the southwest," and the high-value zone for nutrient retention and carbon storage was along the river. (2) From 2005 to 2015, variation characteristics of water conservation, nutrient retention, carbon storage, and biodiversity had an increasing tendency, whereas soil conservation had a decreasing tendency. (3) The five pairwise ecosystem services presented different interactions. The interactions between water conservation and soil conservation, water conservation and nutrient retention, nutrient retention and carbon storage, nutrient retention and biodiversity, soil conservation and carbon storage, and soil conservation and biodiversity presented trade-offs. On the contrary, the interaction between water conservation and carbon storage, water conservation and biodiversity, soil conservation and nutrient retention, and carbon storage and biodiversity were prone to synergistic relationships. Spatially explicit and quantitative assessment of ecosystem service interactions has implications for the planning and management of natural capital and ecosystem services and provides a scientific basis for sustainable development in the Shiyang River Basin. This analysis framework also provides a significant reference with which other river basins can conduct spatial evaluation of ecosystem services.
  • DownLoad:Analysison trade-offs and synergistic relationships among multiple ecosystem services in the Shiyang River Basin.PDF
  • Spatiotemporal pattern of cultural diversity in Southwest China
  • Authors:SHEN Yuan, MAO Shuxin, QIU Sha, LI Tao and DENG Hongbing
  • Abstract:Cultural diversity is just as essential to humankind as biodiversity is to nature, and ethnicity can be used as a rich and concise measurement of cultural diversity. There are a variety of ethnic minorities in Southwest China. During the long history of complex ecosystem development, the ethnic groups in Southwest China have formed many excellent cultural traditions and unique ecological awareness. However, with the deepening modernization of ethnic areas, as well as rapid social transformation, population migration, and cultural changes, ethnic culture that is rooted in social history and traditional customs is suffering from unprecedented change and erosion, which has resulted from the excessive pursuit of economic growth and short-term benefits. Accordingly, studies of cultural diversity in Southwest China have attracted the attention of interdisciplinary scholars. In the present study, the cultural diversity of county-level administrative regions was quantitatively measured using the Shannon-Wiener Index, and dynamic changes among the regions in 1990, 2000, and 2010 were compared to characterize the spatiotemporal distribution of cultural diversity. The cultural diversity of Southwest China exhibited clear spatial heterogeneity, with lower diversity observed in the northwest part of the region and higher diversity observed in the southeast part. In addition, even though cultural diversity increased to a certain degree in the time series, cultural diversity was relatively low at the county scale. However, cultural diversity also increased with the expansion of spatial scale, which demonstrated that ethnic groups tended to live together at large scales but were inclined to cluster together at small scales. Spatial differences in cultural diversity were also observed when using the Theil Index at the province scale, with total and local differences among provinces decreasing over time, and the modified Morisita-Horn Index, which was used to assess similarities of ethnic composition, revealed that the similarity of provinces increased over time. Together, these results indicated that the distribution of ethnic groups in Southwest China was more blended and that ethnic integration has become a trend from 1990 to 2010. Further analysis, using ArcGIS 10.2, also indicated that the distribution of cultural diversity was closely related to the average slope of the distribution areas of ethnic groups in context of Southwest China's ecological environment. The social history and main causes of ethnic integration, reasons for the high cultural diversity of the stepped transition zones, and protection of Southwest China's traditional culture were discussed as well. The present study investigated the spatiotemporal distribution of cultural diversity underlying ecological factors in Southwest China and highlighted the importance of preserving and promoting the splendid cultural traditions of ethnic groups under the premise of respecting the nature. Thereby, it provided a useful reference for the sustainable development of the ecological environment and the construction of ecological civilization in Southwest China.
  • DownLoad:Spatiotemporal pattern of cultural diversity in Southwest China.PDF
  • Attribution of runoff variation in the Wei River basin based on the Budyko hypothesis
  • Authors:ZHANG Limei, ZHAO Guangju, MU Xingmin, GAO Peng and SUN Wenyi
  • Abstract:In recent years, numerous rivers around the world have shown significant changes in runoff due to climate change and human activities. Investigating the causes of changes in runoff is greatly helpful in adapting to climate change and intensive human activities. The present study applied the Mann-Kendall test and the double mass curve method to assess the temporal trends of hydro-climatic variables in the Wei River basin during 1958-2015. The results showed that annual runoff at all three hydrological stations (Xianyang, Zhangjiashan, and Zhuangtou) exhibited a significant decreasing trend (P < 0.05). Annual rainfall and potential evapotranspiration showed decreasing and increasing trends, respectively, but neither were significant. Double mass curve analysis between annual runoff and precipitation showed abrupt changes in annual runoff in the Wei River basin. The periods before abrupt-change points, when runoff retained relatively pristine status and was affected by limited human activities, were regarded as baseline periods. Using the abrupt-change points, we obtained baseline periods of 1958-1970, 1958-1996, and 1958-1992 at Xianyang, Zhangjiashan, and Zhuangtou stations, respectively. The runoff elastic coefficients at each station were estimated using the Budyko hydrothermal equilibrium equation. The results showed that runoff depth was sensitive to the changes in land surface. Compared with runoff in the mainstream Wei River and the Jing River, runoff in the Beiluo River was less sensitive to climate changes. Land surface changes played a dominant role in runoff reduction, followed by precipitation and potential evapotranspiration. Particularly in the mainstream Wei River and Jing River, land surface changes resulting from various human activities contributed more than 60% of runoff reduction.
  • DownLoad:Attribution of runoff variation in the Wei River basin based on the Budyko hypothesis.PDF
  • Assessment of the interception effect of Lijiang River land and water ecotone
  • Authors:LI Zhuoling, WANG Dongmei and REN Yuan
  • Abstract:Lijiang River is a famous tourist scenic spot. In recent years, it faces numerous problems in the dry season in the Lijiang River land crossing zone, including serious exposure of the riverbed, large amounts of sediment in the flood period, and floating debris in the water. As a transitional zone between aquatic and terrestrial ecosystems, the land-water ecotone plays an important role in intercepting water pollutants and protecting river water quality. Here, we studied the interception effect of the land and water ecotone based on the principle of index selection and the current situation in the Lijiang River Scenic Area in the Guangxi Zhuang Autonomous Region. There are 14 indexes in the index evaluation system that are screened from three aspects:the floodplain and slope water blocking effect, the vegetation interception, and soil adsorption. Using the analytic hierarchy process (AHP), the interception effects of the Lijiang River land and water ecotone is divided into 4 grades:excellent, good, general, and poor. The pollution interception effects of 20 plots along both sides of Lijiang River were evaluated. The results show that 2 of the 20 plots retained complete structure. The gravel content of soil is low, the soil layer is thick, the vegetation is rich, and the pollution removal effect is obvious. Thus, their interception effect level is excellent. There were 12 plots rated ‘good’ with relatively complete structure. These are characterized by low gravel content in soil and a thick soil layer. Their vegetation diversity and interception effects are good. Five plots ranked at an general level. Their structure has a certain degree of damage, the soil gravel content is higher, and the soil layer is thin. The vegetation in the plot is singular and the interception effect is normal. There was one plot ranked as ‘poor’, characterized by sparse grass species and a poor interception effect, missing land structure, and largely gravel surface. According to the evaluation results, the best ecological restoration measures are proposed for the Lijiang River land and water ecotone with different interception effects in Lijiang River, which is of guiding significance for the ecological restoration of this area. We suggest a management method to maintain the natural appearance, strengthen the construction of a monitoring system, and improve this ecotone. For the interception of good water and land ecotone, with natural recovery, the appropriate increase in human intervention. And constantly improve the interception of water and land interception function, and long-term monitoring and management. To improve the effect of interception of the ecotone, outplanting and engineering measures should be utilized, supplemented by the ecological restoration model.
  • DownLoad:Assessment of the interception effect of Lijiang River land and water ecotone.PDF
  • Analysis on the adaptability of farmers to ecological and environmental changes and the driving factors in the inner mongolia autonomous region
  • Authors:GUO Xiuli, ZHOU Lihua, CHEN Yong, GU Menghe and ZHAO Minmin
  • Abstract:Adaptability research is a key field of scientific research globally. Its core aim is to improve adaptability. In this study, for constructing the measurement index system of farmers' adaptability to ecological and environment changes, we used principal component analysis to quantitatively evaluate the adaptability of farmers to ecological and environmental changes and analyzed the main driving factors in different regions and different livelihood types of Hangjin Banner, which is located in the hinterland of Kubuqi Desert. The results indicated that:(1) the farmers' adaptability to the ecological and environment changes is poor in Hangjin Banner. Particularly, the adaptability of farmers in the Liangwai area of the southern region is higher than that in the Riverside area of the northern region. The farmers' adaptability to the ecological and environmental changes of the facultative farmers is higher than that of the pure farmers and non-farmers. (2) The driving factors of farmers' adaptability to the ecological environment changes are the degree of labor and livelihood diversification, the status of arable land and material wealth, awareness about the environment, and the infrastructure conditions and status of animal husbandry. Finally, we provided suggestions for improving the adaptability for rural ecological environmental change of Hangjin Banner.
  • DownLoad:Analysis on the adaptability of farmers to ecological and environmental changes and the driving factors in the inner mongolia autonomous region.PDF
  • Decomposition characteristics of the fine root of Phyllostachys edulis and Dicranopteris pedata in southern Sichuan
  • Authors:REN Lining, LIU Shirong, CAI Chunju, WANG Yi, WU Xipin and GUO Mingming
  • Abstract:This study revealed the single and mixed decomposition characteristics of fine roots in bamboo forest and its understory vegetation, explored the potential mechanisms of interaction and function between them,and provides a theoretical reference for the rational management of understory vegetation in Moso bamboo forest. The fine-root in situ decomposition and nutrient release processes of Phyllostachys edulis and understory vegetation (Dicranopteris pedata) in Changning, Sichuan, were investigated using a litter bag, and our test period is 1 year.Our results showed that (1) the initial chemical components of the fine roots of P. edulis and D. pedata were significantly different. The C content and C/N and C/P ratios of P. edulis were significantly higher than those of D. pedata (P < 0.05), while the N content, P content, and N/P ratio of D. pedata were all higher than those of P. edulis (P < 0.05). (2) The decomposition coefficients (k) of P. edulis and D. pedata were 0.66±0.04 and 0.42±0.41, respectively. The rate of fine-root decomposition of P. edulis was higher than that of D. pedata. The soil temperature was positively correlated with the decomposition rate, and it was the key environmental factor affecting the decomposition rate of fine roots. (3) The C, N, and P nutrients showed a net release, and the release rate of C in P. edulis was higher than that in D. pedata, while the release rates of N and P in D. pedata were higher than those in P. edulis. (4) The fine-root mixtures of P. edulis and D. pedata had no significant effect on the decomposition rate and release of P, but significantly promoted the release of C and inhibited the release of N at the initial stage of decomposition. The characteristics of single fine-root decomposition and nutrient release were different between P. edulis and D. pedata. No significant mixed effect of decomposition rate was observed, but the mixed effect of nutrient release showed different stages and directions (positive or negative). The understory vegetation affected the nutrient cycle of the bamboo forest ecosystem by affecting the release of nutrients from the fine roots.
  • DownLoad:Decomposition characteristics of the fine root of Phyllostachys edulis and Dicranopteris pedata in southern Sichuan.PDF
  • Changes in vegetation NDVI from 1982 to 2016 and its responses to climate change in the black-soil area of Northeast China
  • Authors:LIU Jiafu, MA Shuai, LI Shuai, REN Chunying, MAO Dehua and ZHANG Bai
  • Abstract:As an important component of terrestrial ecosystems, vegetation plays an important role in climate regulation, soil and water conservation, and terrestrial carbon balance. The monitoring of vegetation growth and dynamics responsive to climate change therefore become quite necessary to understand global climate change. Based on the GIMMS NDVI and MODIS NDVI as well as a consistency check between these two datasets, this study examined the relationships between the spatiotemporal patterns of the NDVI and climate change over the black-soil area of the Northeast China from 1982 to 2016, using the unary linear regression model at both the pixel and regional scales. Our results showed that, at the regional scale, the NDVI during the growing season presented three different trends across these years (i.e., firstly with an increase, then a decrease, and finally an increase). Regionally, the vegetation growth was jointly affected by temperature and precipitation, which showed significant seasonal changes. By contrast, at the pixel scale, the NDVI exhibited a general increasing trend. The main vegetation types characterized by an increasing trend included grasslands, forests, and crops; and the cities that experienced significant vegetation growth are Hegang, Suihua, and Changchun. The mean NDVI had a close correlation with temperature and precipitation over the same period. Over the regions that are mainly covered by arable lands, the vegetation NDVI was positively related to air temperature, while it had a significant positive correlation with precipitation over the edges of the plains and mountains, where the dominant vegetation types are forests and grasslands.
  • DownLoad:Changes in vegetation NDVI from 1982 to 2016 and its responses to climate change in the black-soil area of Northeast China.PDF
  • Effects of land-use changes on vegetation net primary productivity in the Three Gorges Reservoir Area of Chongqing
  • Authors:ZHAO Xiao, ZHOU Wenzuo, TIAN Luo, HE Wanhua, ZHANG Jincheng, LIU Donghong and YANG Fan
  • Abstract:It is significant to study the impact of land-use changes on vegetation net primary productivity (NPP) both for elucidating the relationship between the carbon assimilation ability of vegetation and the land-use changes on a regional scale, and for maintaining stability in ecosystem structures. By using the section of the Three Gorges Reservoir Area (TGRA) in Chongqing as a study area, we analyzed the spatio-temporal distribution of NPP and the impact of land-use changes on the regional NPP in term of landscape ecology based on the land-use maps and remote sensing data MOD17A3 from 2000 to 2015. The results revealed that the average annual NPP did not change much in over 16 years and it spatially decreased from east to west. During the study period, the areas of woodland increased, whereas the areas of farmland and grassland declined. The total NPP increased from 25.6 TgC to 28.5 TgC, in which comprised 44% in farmland, 40% in woodland, and 14% in grassland. The rates of NPP variations induced by land-use changes in 2000-2005, 2005-2010, and 2010-2015 were 26.49%, 59.76%, and 17.27% respectively. Shannon's diversity index (SHDI) and patch density (PD) were positively correlated with NPP, whereas the aggregation index (AI) was negatively correlated with NPP. Both the types and their changes of landscape patterns increased NPP. To improve the regional vegetation NPP, some measures, which includes optimizing the land-use pattern, increasing the landscape heterogeneity and patch density, emphasizing the cultivation of young forest, and controlling the number of mature forests, need to be adopted by local governments in the future.
  • DownLoad:Effects of land-use changes on vegetation net primary productivity in the Three Gorges Reservoir Area of Chongqing.PDF
  • The study of the effect of tree death on spatial pattern and habitat associations in dominant populations of Dongling Mountains in Beijing
  • Authors:MA Fang, WANG Shunzhong, FENG Jinchao and SANG Weiguo
  • Abstract:Research on forest community dynamics and its correlation with environmental factors have been one of the important topics in ecology. Tree death is a vital aspect of forest community dynamics. Environmental factors play significant roles in tree death; therefore, the correlation between wood death and environmental factors for analysis of forest trends need to be studied. The research was performed in a 20 hm2 warm temperate secondary deciduous broadleaved mixed forest dynamics plot to investigate the population quantity characteristic, spatial distribution, and the relationship of the habitat, before and after tree death (before the death:living tree stand; after death:dead tree stand and log). The data were analyzed using point pattern, species-habitat correlation. The results were as follows:(1) Before the death, Quercus mongolica > Betula dahurica > Populus davidiana > Larix principis-rupprechtii. After the death, the order was P. davidiana > B. dahurica > Q. mongolica > L. principis-rupprechtii. Before and after the death, the distribution pattern changed from aggregation to random with the increase in sampling scale. (2) The association analysis of populations and habitats showed that the living standing trees of P. davidiana, B. dahurica, L. principis-rupprechtii were randomly distributed, Q. mongolica were clustered on gentle slopes, there was a higher distribution of P. davidiana and Q. mongolica saplings on the gentle slopes, that of B. dahurica was random, and L. principis-rupprechtii was concentrated on the ridges. There were many steep slopes of fallen P. davidiana, and B. dahurica, and Q. mongolica that were concentrated on the ridge. (3) The spatial pattern of different populations before and after death, appeared to be obvious scale dependence, and were related to the biological characteristics of the species, density constraints, and the process of habitat filtration.
  • DownLoad:The study of the effect of tree death on spatial pattern and habitat associations in dominant populations of Dongling Mountains in Beijing.PDF
  • A comparative study on the underwater decomposition of live and dried Carex cinerascens and Phalaris arundinacea
  • Authors:GAO Minmin, WAN Lingfan, MA Yantian, ZOU Feng, HE Liang, LIU Yizhen and GE Gang
  • Abstract:To reveal the difference in the rates of underwater decomposition between living plants and litters in Poyang Lake wetland, this study was conducted involving a microcosm experiment with two predominant species-Carex cinerascens and Phalaris arundinacea-using the litter bag method. Fresh and dried plant samples were prepared to simulate the decomposition processes of living plants and natural litters, respectively. The results showed that:(1) The decomposition process of both plants (C. cinerascens and P. arundinacea), lasting 180 days, had a quick primary stage and a slower later stage. (2) The decomposition rates of both litter samples were significantly correlated with their C/N ratios, but similar correlation was not found in the living samples. (3) The underwater decomposition rate was related with the species; the living P. arundinacea decomposed faster than its litters, while living C. cinerascens decomposed slower than its litters. (4) At the end of the experiment, 34%-43% of the living plants remained undecomposed. We speculated that aquatic erosion and foraging by animals had important contribution to the disappearance of large plants after the lowering of water levels in the Poyang Lake wetland.
  • DownLoad:A comparative study on the underwater decomposition of live and dried Carex cinerascens and Phalaris arundinacea.PDF
  • Quantitative research of agricultural biomass resources for energy utilization in a typical karst mountain area: a case study of Guizhou Province
  • Authors:YING Bin, WANG Qi, XIONG Kangning, REN Wei and AO Wenxiu
  • Abstract:The fragile eco-environment, together with low efficiency energy utilization, are typical features of the social-ecological system in Karst mountain areas. It is of great value to determine the potential agricultural biomass resources (ABR) for rural energy construction, and ecological environmental protection of these areas. Based on a case study of Guizhou Province, considering the returning ecological straw biomass for soil and water conservation, this paper estimated the total available ABR in rural areas using the residue to product ratio, ecological returning coefficient, collection coefficient, conversion coefficient to standard energy, and process residue factor. The results showed that:(1) from 2009 to 2015, the ABR of Guizhou Province increased to 5191.50×104 tce annually, with a density of 295 tce/km2 and 1.48 tce/person, respectively. About 1974.05×104 tce of energy-oriented biomass resources are available annually, accounting for 21.85% of the total energy consumption during the same period in Guizhou; (2) the proportion of biomass energy reserves in Guizhou Province is unevenly distributed. The potential utilization of livestock and poultry waste is considerable, with a contribution value up to 85%; the average amount of cattle feces biomass is up to 3009.78×104 tce annually, with a 68.39% contribution to the total animal excrement, which is the most important ABR in Guizhou Province; (3) a U-shaped temporal characteristic change in ABR occurred during 2009 to 2015 in Guizhou Province, with the lowest level in 2011, which showed a coupling with an important ecological event of the southwest drought disaster in 2010. Finally, based on the current agricultural biomass resources in Guizhou Province, this paper suggests that the straw power plants and straw curing for fuel factories should be distributed evenly in the karst mountain area, improving the current scale of livestock breeding, strengthening agricultural disaster prevention, and popularizing the comprehensive utilization of biogas, efficient firewood stoves, and energy saving straw gases in karst rocky desertification areas.
  • DownLoad:Quantitative research of agricultural biomass resources for energy utilization in a typical karst mountain area: a case study of Guizhou Province.PDF
  • Plant functional traits and the factors influencing them in the islands of eastern China
  • Authors:CHEN Sisi and HUANG Xiuqing
  • Abstract:Plant functional traits can be used to reflect the responses of plants to environmental changes. In order to understand how plant functional traits change along the environmental gradients and to find the factors driving such changes, especially in the islands of eastern China, six plant functional traits, including diameter at breast height (DBH), tree height (H), mean leaf area (MLA), specific leaf area (SLA), twig wood density (TWD), and twig water content (TWC), were measured in typical plant communities in seven islands. One-way analysis of variance was used to compare the variations in traits among different climatic zones. Stepwise regression analysis was used for quantifying relationships between traits and seven environmental factors (soil total carbon, soil total nitrogen, soil total phosphorus, soil water content, mean annual temperature, mean annual precipitation, and mean annual wind speed). The results showed that:(1) Significant differences exist in most plant functional traits among different climatic zones except SLA, but the functional traits of evergreen and deciduous plants differ among climatic zones, which indicated that plants of different life forms have different reaction and adaptation to the environment. (2) Climatic factors, rather than soil factors, are the main controllers of trait differences along the gradient. Plants in the southern islands have higher DBH and TWC, lower MLA and TWD. The results in northern islands are opposite. Moreover, twig wood traits (TWD and TWC) are significantly influenced by mean annual wind speed in the islands. These results may offer a reference for selecting suitable species for afforestation and reforestation programs in the islands.
  • DownLoad:Plant functional traits and the factors influencing them in the islands of eastern China.PDF
  • Sex ratio and spatial distribution of Salix gordejevii in Hunshandake Sandy Land
  • Authors:MA Shaowei, LIU Guohou, LIU Lihong, ZHANG Cen, LIU Guanzhi, GUO Jiao, WANG Lei and E Jiaqing
  • Abstract:Sex ratio and spatial distribution of dioecious plants play an important role in reproductive strategy, population evolution, and development. Salix gordejevii, a typical dioecious plant, is an important sand-fixing pioneer plant in Hunshandake Sandy Land and is widely distributed in flowing and semi-flowing sandy land. But the current understanding of the structure and distribution of male and female populations is still limited. In our study, we chose natural populations in Zhagesitai, Yinmajing, Bagelai, and Baoshaodai, and investigated the sex ratio, spatial distribution pattern, and spatial relationship using statistics and point pattern analysis. Our objectives were to examine (1) whether the sex ratio deviated from 1:1 in the S. gordejevii population, and if so, (2) whether the sexual spatial segregation (SSS) phenomenon existed. The results showed that the morphological differences between male and female populations are closely related to the environmental conditions of the population. The sex ratio (female/male) was female-biased (P < 0.01) in different sampling plots (50 m×50 m) and was determined by the number of male and female individuals in diameter classes I and Ⅱ. The sex ratio gradually approached 1:1 as age increased. Male and female populations of each population were mainly distributed in a clumped pattern on a 0-25 m scale, and were occasionally randomly distributed on a small scale. This phenomenon may be because the seed regeneration ability of S. gordejevii is weak, and clonal reproduction ability is strong. The spatial relationships between male and female populations were independent of each other in Zhagesitai, Yinmajing, and Bagelai, which indicated that competition between sexes was not intense. However, the spatial relationship of gender was mutually exclusive in Baoshaodai and SSS existed in the population. This phenomenon is mainly because of the relative lack of resources (e.g., lower soil moisture, organic matter, and total nitrogen) and the close proximity between male and female individuals in Baoshaodai. In conclusion, the sex ratio (female/male) was female-biased in the S. gordejevii population. Male and female populations were mainly distributed in a clumped pattern on all scales, and there was SSS in relatively resource-limited area. In addition, dioecious-plant-population regeneration was influenced by sex ratio and distribution pattern; thus, these should be considered when determining the proportion and spatial location of male and female individuals during afforestation. This study revealed the composition, structure, and distribution of male and female populations of S. gordejevii, and laid a theoretical foundation for improving the stability of the artificial forest community.
  • DownLoad:Sex ratio and spatial distribution of Salix gordejevii in Hunshandake Sandy Land.PDF
  • Changes in inundation frequency in Poyang Lake and the response of wetland vegetation
  • Authors:GU Juan, QIN Yi, WANG Xin, MA Jingyu, GUO Zhonghao, ZOU Lejun and SHEN Xiaohua
  • Abstract:In lake ecosystems, the timing, duration, and frequency of inundation greatly determines the wetland/aquatic ecological conditions, and influence wetland plant regeneration and species richness. Under increasing impacts from human activities and climate change, a better understanding of how hydrological changes influence wetland vegetation is required. In this study, we analyze the spatial distribution of the inundation frequency and its temporal variation during the period from 2000 to 2015 in Poyang Lake by means of MODIS image interpretations method based on mixed pixel decomposition model derived from the spectrum characteristics of ground features. The relationship between the inundation frequency and the vegetation abundance is further discussed. The main results are as follows:(1) the spatial distribution of inundation frequency in the receding period shows a decreasing trend from north to south on the whole. Areas with high inundation frequency are distributed in patches. (2) The inundation frequency of the whole lake decreased from 2000 to 2010, then recovered to a relative stable state from 2011 to 2015. In different regions of the lake, the temporal changes of inundation frequency in the last 15 years shows different trends. The inundation frequency of the northern river channel and that of the central shoal shows trends similar to that of the whole lake, except that the changes of inundation frequency in the central shoal are gentler. On the other hand, the inundation frequency of the southern sub-lake is basically unchanged. (3) The vegetation abundance closely responds to the inundation frequency of Poyang Lake. The "n" form distribution on the scatter diagram of vegetation abundance versus inundation frequency shows that there were high values in the central part and low values on both sides, and the vegetation abundance reaches a maximum when the inundation frequency equals~40%. (4) The relationship between the inundation frequency and the vegetation abundance indicates a positive spatial evolution of emergent aquatic vegetation in Poyang Lake.
  • DownLoad:Changes in inundation frequency in Poyang Lake and the response of wetland vegetation.PDF
  • Biogeographic patterns and influencing factors of the species diversity of tree layer community in typical forest ecosystems in China
  • Authors:WU Anchi, DENG Xiangwen, REN Xiaoli, XIANG Wenhua, ZHANG Li, GE Rong, NIU Zhongen, HE Honglin and HE Lijie
  • Abstract:Large-scale patterns of species diversity are one of the most important and attractive issues of ecology and biogeography. Using the investigation data of tree layers in 13 typical forest ecosystems in China, we explored the geographical patterns and main influencing factors of species diversity in the forest community. Our results indicated that four species diversity indices decreased with an increase in latitude and longitude in the 13 typical forest ecosystems. Species richness, in particular, showed a significant variation along both latitude and longitude gradients, while the other indices showed a significant change only with an increase in latitude. A regression analysis showed that the species diversity indices were not consistent in correlation with a single factor, i.e., plant traits, energy, and moisture factor. The indices such as, species richness, Shannon-Wiener index, and Simpson index, showed the most remarkable correlation with the annual average temperature, coldest month average temperature, annual temperature difference, and potential evapotranspiration (P < 0.01). The Pielou index showed a significant correlation with the annual mean temperature, mean temperature of the coldest month, actual evapotranspiration, potential evapotranspiration, and crown density (P < 0.05). A variation partitioning analysis demonstrated that the synergy of energy and moisture had the highest explanation rate for the spatial distribution of species diversity index, reaching 15%-42%, and the interactions among plant traits, energy, and moisture factors had a secondary effect on the geographic distribution patterns of species diversity, with an explanation rate of 14%-27%. Furthermore, the shared effects of the other combinations of plant traits and energy factors were insignificant. The effect of energy factors on the distribution of species diversity indices was higher than the effect of plant traits or moisture in determining the species diversity in 13 typical forest ecosystems. Our results revealed that the shared effects of energy and moisture were the most crucial factors impacting the development of large-scale species diversity in the studied forest tree layer. Meanwhile, the effects of plant traits should not be ignored.
  • DownLoad:Biogeographic patterns and influencing factors of the species diversity of tree layer community in typical forest ecosystems in China.PDF
  • Study on the characteristics of bacterial community succession in tobacco aging
  • Authors:ZHOU Jiaxi, YU Lifei, ZHANG Jian, ZHANG Xiaomin, HU Daming, OU Mingyi and ZOU Xiao
  • Abstract:In this study, we investigated the relationship between the community succession and chemical composition of the bacteria isolated from tobacco. The tobacco sample C3F (2013) obtained from Baoshan City, Yunnan Province, was stored in Guiyang (GY), Tanchang (TC), and Ziyun (ZY) storerooms. The 16S rRNA genes of the bacteria isolated from the samples aged 0, 6, 12, 18, and 24 months were sequenced using the Illumina HiSeq2500 high-throughput sequencing platform. The results showed that the Pseudomonas, Sphingomonas, Stenotrophomonas, and Bacillus genera were dominant in the bacterial community. With an increase in aging time, a growth-decline trend was observed between Proteobacteria and Firmicutes in the dominant bacterial communities, and the genus Bacillus was significantly dominant in the later successional stage. In the process of tobacco aging, a significant correlation was found between the dominant functional groups of bacteria and the progressive decomposition of their chemical components. The dynamics of the dominant functional groups of bacteria changed from carbohydrate-like to starch-like and then to cellulose-like. The water-soluble sugar and cellulose were the key factors involved in succession. This study revealed a significant characteristic of the bacterial community succession during aging in tobacco, thereby elucidating the mechanism of tobacco aging and providing a scientific basis for using microbes to control tobacco aging.
  • DownLoad:Study on the characteristics of bacterial community succession in tobacco aging.PDF
  • The adaptability of woody plants to the rock morphostructure in karst rocky habitat
  • Authors:WANG Meiquan and HUANG Zongsheng
  • Abstract:The objective of this study was to characterize plant adaptation to the morphostructure of rock in karst areas. Selecting seven types of woody communities growing on three rock types (limestone, dolomite rock, dolomitic sandstone) as test objects, the fractal dimension and spatial syntax were adopted to study the morphostructure of cracks and pores of the rock structural plane, and its correlations with the characteristics of plant communities. Results indicated that the lacunarity index of cracks and pores of the limestone structural plane was the largest, that of dolomite was intermediate, and that of dolomitic sandstone was the smallest. The fractal dimension showed the opposite trend to that of the lacunarity index. With respect to the integration degree, control value, and density value of cracks and pores, the rocky structural plane of dolomitic sandstone was ranked as the largest, followed by that of dolomite, while that of limestone was the smallest. The species diversity and the carbon and nitrogen content of the dominant species in dolomite habitat were the highest, followed by those in the dolomitic sandstone habitat, while these were the lowest in the limestone habitat. The index of fractal dimension had a significant correlation with the index of spatial syntax, both of which could reveal the rock morphostructure well. In general, the species diversity index and the carbon and nitrogen content of the dominant species had a strong correlation with the fractal dimension index and the spatial syntax. Provided that the growing environment is similar, the rock morphosturcture of dolomite was the most suitable for plant growth, followed by that of dolomitic sandstone. However, the rock morphostructure of limestone was comparatively unfit for plant growth. It is necessary to study the rock morphostructure in karst areas for vegetation restoration in these areas.
  • DownLoad:The adaptability of woody plants to the rock morphostructure in karst rocky habitat.PDF
  • Growth dynamics and competitive strategies of fine roots in a walnut-wheat agroforestry system
  • Authors:WANG Lai, GAO Pengxiang, ZHONG Chonggao, LIU Bin, HOU Lin, ZHAO Yujian, ZHANG Shuoxin and ZHANG Yuanying
  • Abstract:The competition and ecological plasticity of fine roots between intercropping trees and alley crops are vital for the sustainable management in agroforestry system. To understand the interspecific competition and the adaptive strategy of fine roots in agroforestry system, both minirhizotron and soil core methods were used in investigating the dynamic of fine roots in the walnut-wheat (Juglans regia-Triticum aestivum) intercropping system at Weibei loess area. The monocultural systems were compared with the intercropping one. The results showed that there were two growth peaks of both walnut and wheat roots in the agroforestry system. One was from April to May and the other was from September to November. During April and May, large root biomass was gained and the major interspecific competition took place between walnuts and wheats. The root length density of walnut in the intercropping system was lower than walnut monoculture system at all the soil layers during all the growth periods. A significant difference was found since the 7th year after planting. In surface soil (0-20 cm), the root length density of wheat increased rapidly from the 3th to 7th year in the intercropping system, and became significantly greater than the wheat monoculture since the 7th year. However, the opposite trend was observed in the soil layer below 20 cm. The root ecological niche of walnut and wheat separated in the intercropping system. The roots vertical distribution center of walnut and wheat moved down for 6.59 cm and moved up for 8.59 cm than that in the walnut and wheat monoculture systems, respectively. In the aspect of root competition strategy, the wheat took competitive advantage through rapid growth and occupied more space in a short term than the walnut, however, the walnut trees took the space by accumulating their roots year by year and gradually took the advantageous place in the intercropping system. Walnut and wheat coexisted in the agroforestry system following the "competition-disturbance-rebalance" management strategy, which can interfere with the accumulation process of walnut root. In root morphology respect, wheat, whose fine root diameter was smaller at the beginning, tended to increase fine root diameter and reduce specific root length. However, the opposite trend was found for the walnut in the agroforestry system.
  • DownLoad:Growth dynamics and competitive strategies of fine roots in a walnut-wheat agroforestry system.PDF
  • C, N, and P stoichiometry and their interaction with plants, litter, and soil in a Cunninghamia lanceolata plantation with different ages
  • Authors:LI Mingjun, YU Lifei, DU Mingfeng, HUANG Zongsheng and SHI Jianhua
  • Abstract:In this study, three different stand ages of Cunninghamia Lanceolata plantations in Guizhou Province, including 8-year-old, 16-year-old and 28-year-old, were selected as the objects. In order to provide the scientific basis for sustainable management of Cunninghamia Lanceolata plantations, we explored carbon (C), nitrogen (N) and phosphorus (P) ecological stoichiometry and their interaction of plant, litter and soil, to indicate the effects of stand ages on the stoichiometry. Our results showed that, (1) The nutrient stucture of leaf, litter and soil presented high concentration of C and low concentration of N and P in Cunninghamia Lanceolata plantations. The concentration and stoichiometric ratio of C, N, and P were significant different among plant, litter and soil (P < 0.05).The C/N (38.58) and C/P (376.67) of leaf were lower than those of other coniferous trees, demonstrating that nutrient use efficiency of Cunninghamia Lanceolata was poor. Conversely, C/N and C/P of litter were higher than those of leaf, on account of N and P concentrations of litter were lower than those of leaf. The soil C/P and N/P were lower and C/N was higher, indicated that N release was inhibited but P decomposition was reversely accelerated in soil, and it suggested that the condition would inhibit the litter decomposition and nutrients release. (2) The C, N, and P concentrations and stoichiometric ratios of root, litter, and soil, as well as C and P concentrations of mature leaf, were significantly different among the three age groups. From 8 to 28 years old, the C, N and P concentrations of plant increased firstly and then decreased, but the results were converse in soil, suggesting that plant nutrient uptake significantly increased firstly and then decreased. This could result in soil nutrients being transformed from consumption to accumulation. The C and P concentrations of litter significantly decreased, and litter C/P and N/P ratios significantly increased, suggesting that P was the main factor that constrains litter decomposition. Thus, P may have inhibited nutrient return and intensified the contradiction between the nutrients supply and demand in young and middle aged forests. (3) N concentration, C/N and N/P of matured leaf had significantly positive correlations with those of litter, indicating that the nutrients of litter were sourced from the matured leaf. Resorption efficiency of P (0.518-0.645) was significantly greater than that of N (0.292-0.488) (P < 0.05), indicating that utilizing efficiency of P was greater than that of N in the plantations. C concentration and C/N of litter had significant negative correlations with those of soil, suggesting that C and N concentrations of soil was sourced from litter decomposition. However, litter decomposition was a slow process, accompanied with a plentiful nutrients reserved in litter, which delayed nutrient return from litter to soil. Concentrations of C and P, C/N, C/P and N/P of root had significantly positive correlations with those of soil, meanwhile, concentrations of C, P and N of soil had no significant correlations with those of matured leaf,suggesting that soil nutrients were the main sources of plant nutrients, but had less influence on concentrations of C, N, and P of matured leaf.
  • DownLoad:C, N, and P stoichiometry and their interaction with plants, litter, and soil in a Cunninghamia lanceolata plantation with different ages.PDF
  • Analysis of the impact of rapid urbanization on farmland protection in the Yangtze River Economic Belt
  • Authors:HE Liang, LI Weifeng, TIAN Shufang and ZHENG Hua
  • Abstract:As one of the three major development strategies of our country, the impact of rapid urbanization of the Yangtze River Economic Belt on farmland resources cannot be ignored. The main problem facing China's urbanization is the massive encroachment on farmland by the rapid urbanization of land. However, in recent years, the rapid development of the Yangtze River Basin and the Yangtze River Economic Belt and its impact on farmland resources is still lacking a comprehensive and systematic analysis. This study is based on remote sensing data of middle resolution, to cover the Yangtze River Economic Belt and the Yangtze River Basin within the scope of 156 prefecture-level cities as the research objectives. The impact of urbanization on farmland from 2000 to 2015 was analyzed from the perspective of combining natural locations (upper, middle, and lower reaches) and urban size (population size), and the results show that:(1) From 2000 to 2015, the artificial surface in the Yangtze River Basin and the Yangtze River Economic Belt increased by 56.80% in total and the farmland decreased by 17.09%. Among these areas, the artificial surface of the lower reaches shows the most significant increase, and the reduction of arable land is the most obvious; (2) As time passes, the pressure of urbanization on farmland in the Yangtze River Basin and the Yangtze River Economic Belt is gradually decreasing, and the artificial surface growth rate increased from 2733.75 km2/a to 2985.87 km2/a over the past 15 years, while the rate of decrease in farmland decreased from 4439.94 km2/a to 3940.91 km2/a, with a large number of dry fields changed to paddy fields; (3) For cities of different sizes located in different basins, there is a significant difference in the impact of the increase of artificial surface on farmland. For example, the artificial surface of the medium-sized cities in the lower reaches of the Yangtze River increased most (increase range 385.88%) in 15 years, and the farmland also lost the most; the metropolitan cities in the middle reaches of the Yangtze River have the fastest artificial surface growth rates, while the upper reaches are huge cities, this phenomenon shows that there is an uncoordinated development in the Yangtze River Basin. The optimal layout of cities in the future along the Yangtze River Basin and Economic Belt should not only give full consideration to the protection of farmland but also balance the expansion speed of cities of different sizes and further improve the utilization efficiency of development land.
  • DownLoad:Analysis of the impact of rapid urbanization on farmland protection in the Yangtze River Economic Belt.PDF
  • Dynamics and allocation patterns of carbon and nitrogen storage in Picea asperata plantations in subalpine areas of Gansu Province
  • Authors:YUE Junwei, GUAN Jinhong, DENG Lei, ZHANG Jianguo, LI Guoqing and DU Sheng
  • Abstract:Picea asperata is an important afforestation species in the subalpine region of Gansu Province. The estimation of carbon and nitrogen storage in P. asperata plantations is helpful to evaluate the ecological restoration effects after afforestation. To estimate the dynamics and allocation patterns of carbon and nitrogen storage, 16 field plots of different forest ages (including young forests, mid-aged forests, near-mature forests, and mature forests) in the P. asperata plantations in Gannan Tibetan Autonomous Prefecture and Dingxi City were established. Vegetation, litter, and soil were investigated and sampled for laboratory analyses. The results showed that carbon contents of different organs in the tree layer were relatively stable, while nitrogen contents were closely related to organ types. Carbon and nitrogen contents in the same soil layer had no significant difference among different stand ages. The ratio of carbon to nitrogen content was higher in tree layer than that in shrub, grass, and litter layer, and soil layer had the lowest ratio. In this area, the total storage of carbon and nitrogen in the ecosystem was up to 257.75-430.23 and 20.50-29.88 t/hm2, respectively. As stand age increased, the biomass carbon storage increased from 15.51 to 143.51 t/hm2 while the nitrogen in biomass increased from 0.24 to 1.65 t/hm2. However, carbon and nitrogen storage in the soil (0-100 cm) was 242.23-367.79 and 20.26-29.58 t/hm2, respectively, and showed no significant differences among stand age groups. Soil stored more than 60% of carbon storage and more than 90% of nitrogen storage in the total ecosystem in each age class. Carbon storage in soil layer, tree layer, and shrub/grass/litter layer accounted for 85.72%, 13.44%, and 0.84% of that in the whole ecosystem, while nitrogen storage in the corresponding layers were 97.60%, 2.08%, and 0.32%, respectively.
  • DownLoad:Dynamics and allocation patterns of carbon and nitrogen storage in Picea asperata plantations in subalpine areas of Gansu Province.PDF
  • Effect of land use and cover change on carbon stock dynamics in a typical desert oasis
  • Authors:KONG Junqia, YANG Rong, SU Yongzhong and FU Zhide
  • Abstract:Accurate estimations of the effects of land use and cover change (LUCC) on regional carbon stock has become one of the focuses in research on the regional carbon cycle. Based on the map of land use/cover and the data of soil/vegetation carbon density in different periods, the Bookkeeping model was used to assess the effects of LUCC on carbon stocks in the Linze desert oasis over the past 30 years. Results showed three points as follows:firstly, characteristics of LUCC in Linze Oasis were mainly affected by the increase of in residential, construction, and arable land and woodland, at the rate of 90.2%, 75.0%, and 46.5%, respectively. At the same time, saline-alkali land, water area, sandy land, and desert grassland showed a decreasing trend at the rate of 73.9%, 67.8%, 46.2%, and 5.5%, respectively. Secondly, the total area of arable land increased by 269.38 km2. The new area of agricultural reclamation reached 372.57 km2, which was mainly from the saline-alkali land, sandy land, and desert grassland, accounting for 24.7%, 24.4%, and 21.05% of the reclaimed arable land, respectively. Meanwhile, 103.19 km2 of arable land had changed into saline-alkali land, sandy land, and desert grassland, accounting for 32.78%, 17.80%, and 15.37% of the lost arable land, respectively. Thirdly, influenced by the changes of land use in the study area, vegetation, soil, and the total carbon stock increased by 1.86×105 t, 4.02×105 t, and 5.89×105 t, respectively. The carbon stock increased by 4.91×105 t due to the changes of arable land, in which, transition processes from desert grassland, sandy land, woodland, and saline-alkali land to arable land led to an increase in carbon stock, while the reverse processes led to a decreasing trend in carbon stock. Overall, both the area and the structure of land use/cover types in Linze Oasis had changed over past 30 years, in which, the reclamation of arable land was the main change process. More importantly, land use/cover change led to a total increase in carbon stock in Linze Oasis, which can be mainly explained by the change of arable land.
  • DownLoad:Effect of land use and cover change on carbon stock dynamics in a typical desert oasis.PDF
  • Improvement and application of reference-site approach in soil baseline determination
  • Authors:HAN Linwei, QUAN Yuan, FU Xiao, SHAN Peng and WU Gang
  • Abstract:Baseline is the basis and precondition of environmental damage identification and assessment. As one of the most widely used methods for baseline determination, the reference-site approach makes up for the shortage of historical data. However, as the key point of the reference-site approach, the selection of the reference site still has some problems, including the lack of clear standards and low credibility. To address these problems and provide a clear way and standard for the selection of reference sites, the reference site similarity evaluation index system for the soil baseline was proposed. Using the Shengli no.1 open-pit mine in Xilin Hot as an example, the baseline for soil damage was determined, and the result was compared with historical data. The results showed that the soil baseline calculated by the reference-site approach, to some degree, was authentic and reliable, and the practicability of the reference-site approach could be improved under the premise of ensuring the reliability of reference-site selection through controlling the main environmental factors related to the research.
  • DownLoad:Improvement and application of reference-site approach in soil baseline determination.PDF
  • Effects of intensive management on the community structure and diversity of CO2-assimilating bacteria in a Phyllostachys pubescens stand
  • Authors:LIU Caixia, ZHOU Yan, XU Qiufang, CHEN Junhui, QIN Hua, LI Yongchun and LIANG Xue
  • Abstract:We examined the relative effects of long-term (25 years) intensive management on abundance and diversity of soil CO2-assimilating bacteria in a Phyllostachys pubescens (moso bamboo) forest. Soil samples in moso bamboo stands receiving 0 (control; CK), 10, 15, 20, and 25 years of intensive management were collected from the topsoil (0-20 cm) and subsoil (20-40 cm) layers separately and analyzed using quantitative PCR (q-PCR), terminal restriction fragment length polymorphism (T-RFLP), and a clone library of the cbbL gene. Differences in the community structure of CO2-assimilating bacteria over time and its relationship with soil properties were detected using redundancy analysis (RDA). We found that long-term intensive management significantly increased soil nutrient content but decreased soil pH. Among the soil parameters measured, N content influenced cbbL abundance, but soil organic carbon (SOC) did not. During the intensive management process, the bacterial cbbL abundance in topsoil increased in the first 10 years and then decreased, and it correlated positively with nitrogen levels (P < 0.05); conversely, in subsoil, cbbL abundance decreased linearly with time and showed a positive correlation with C:N ratio (P < 0.05). Intensive management of P. pubescens altered the community structure of CO2-assimilating bacteria in both topsoil and subsoil, and induced a decline in the species diversity indices of CO2-assimilating bacteria in topsoil. The results for the cbbL clone library indicated that uncultured bacteria accounted for up to 56% of the species present. The dominant species in the soil were facultative autotrophic bacteria such as Proteobacteria and Actinobacteria. RDA indicated that the changes in community structure and diversity of CO2-assimilating bacteria resulted from soil acidification and nutrient accumulation.
  • DownLoad:Effects of intensive management on the community structure and diversity of CO2-assimilating bacteria in a Phyllostachys pubescens stand.PDF
  • Effects of litter on soil respiration under simulated nitrogen deposition in a Cinnamomum camphora forest
  • Authors:CHEN Yi, YAN Wende, ZHENG Wei, LIAO Juyang, PAN Yuliang, LIANG Xiaocui and YANG Kun
  • Abstract:We evaluated the effects of different litter treatments on soil respiration under the influence of nitrogen deposition in a camphor plantation forest in Hunan Botanical Garden, China.We used four different levels of nitrogen, including CK (0 kg N hm-2 a-1), LN (50 kg N hm-2 a-1), NM (150 kg N hm-2 a-1), and HN (300 kg N hm-2 a-1), and three litter treatments, including litter removal, doubled litter, and litter control group (no litter treatment).After two years of observation, the following major results were obtained:(1) Soil temperature showed significant seasonal changes, but no significant difference was observed in soil temperature with different litter treatments under simulated nitrogen deposition. However, soil moisture showed significant fluctuations. Soil moisture was affected only by litter management. A significant difference was observed in soil moisture with litter removal and doubled litter under different levels of nitrogen. (2) With different litter treatments under simulated nitrogen deposition, soil respiration showed significant seasonal changes; the maximum respiration rates were obtained from June to August and the minimum in January. During the growing season (April-August), a significant difference was observed in soil respiration with different treatments. (3) Soil respiration was inhibited by nitrogen applications; however,soil respiration was promoted by the addition of litter and inhibited by its removal. (4)Compared with CK, the soil respiration rates of LN-, MN-, and HN-treated soil significantly decreased by 35.4%, 30.6%, and 36.8% in the litter control group (P < 0.05); by 23.2%, 15.8%, and 14.7% in the doubled litter group; and by 3.5%, 0.5%, -11.6% in the litter removed group. The addition or removal of litter could weaken the inhibitory effect of nitrogen on soil respiration. Moreover, this effect increases with increasing nitrogen levels. (5)A significant correlation was found between soil respiration and soil temperature at a soil depth of 5 cm (P < 0.05). Soil temperature could explain a variation of 47.76%-72.61% in soil respiration, and no significant correlation was found between soil respiration and soil moisture (P > 0.05).
  • DownLoad:Effects of litter on soil respiration under simulated nitrogen deposition in a Cinnamomum camphora forest.PDF
  • Effect of soil nematode communities on the home-field advantage of forest litter decomposition
  • Authors:WANG Yang, WANG Xuefeng and ZHANG Weidong
  • Abstract:This study expounded the effect of soil nematode communities on the home-field advantage of the leaf litter decomposition of Pinus thunbergii Parl and Quercus liaotungensis Koidz,using litterbags with different mesh sizes in Dalian National Forest Park, China. We analyzed the soil nematode community composition, diversity and distribution, litter decomposition rate, and nutrient release. Furthermore, we studied a correlation between the number of nematodes, number of genera, ecological indices, and litter physico-chemical properties. The results showed that a total of 4570 nematodes belonging to 35 genera were collected. The number of nematodes collected in 0.1-mm litter bags (4407) was significantly more than that of the nematodes collected in 0.02-mm litter bags (163). Litter decomposition was driven by soil nematodes and microorganisms in the treatment with 0.1-mm litter bags. However, soil nematodes were controlled by 0.02-mm litter bags; therefore, soil nematodes were regarded as the only microorganisms involved in litter decomposition. An increase was observed in the difference of litter loss rate and element residual rate between home and away. It showed that soil nematodes had an obvious effect on the home-field litter decomposition. Litter mass loss rate and C、N release quantity in 0.1-mm litter bags were more than that in 0.02-mm litter bags. Litter mass loss rate and C、N release quantity in the home environment were more than that in the away environment. Some differences in the environment of home and away showed that soil nematodes promoted litter decomposition and significantly contributed to home-field. In the home environment, soil nematodes showed a high degree of community richness, regulated and controlled community structure and edaphon activity, and further accelerated litter decomposition and nutrient release. Meanwhile, the home-field advantage also determined litter decomposition rate and nutrient release. These results will provide a reference for the home-field and away-field advantage of litter decomposition and for the soil organism-driven effect on the forest litter decomposition in a related study in the future.
  • DownLoad:Effect of soil nematode communities on the home-field advantage of forest litter decomposition.PDF
  • Evaluation of soil quality of Chinese prickly ash artificial orchard at different altitudes in Guizhou karst mountainous area
  • Authors:YU Yanghua, WANG Lu, ZHONG Xinping and QIN Shiyi
  • Abstract:We examined the soil nutrient content of a Chinese prickly ash artificial orchard in the Guizhou karst mountainous area; its comprehensive quality index is of great significance. In this study, soils at different altitudes have been collected from Guizhou karst mountainous area and samples were analyzed by using techniques of agricultural soil chemistry and environmental mineralogy. The study results indicated that the pH values of soils at different altitudes had significant differences, with a trend of increasing-decreasing with increased altitude; the soil organic carbon, total nitrogen, and available nitrogen of soil in the sample plots at the lowest altitude (594 m, HJ1) and the highest altitude (884 m, HJ5) were all significantly higher than those of the three sample plots at the middle altitudes (660 m, 705 m, 778 m, HJ2-HJ4), while the trend in the total phosphorus was exactly opposite to that of the available phosphorus. However, there is no significant differences among concentrations of mineral elements in the Chinese prickly ash orchards at different altitudes was not obvious; the contents of total sulfur, lead, cadmium, and selenium with the highest altitude have been determined. There were significant correlations among nitrogen, phosphorus, and other mineral elements, suggesting a close relationship. The soil quality comprehensive index was HJ5 (2.16) > HJ3 (0.43) > HJ4 (0.19) > HJ1 (-0.21) > HJ2 (-2.60), suggesting that the surface soil quality of Chinese prickly ash orchard at high altitudes is better than that at low altitudes, comprehensively speaking, revealing that soil nutrient content changed along with the change in altitude. As a result, it is suggesting that organic fertilizer and mineral element fertilizer could be used simultaneously to improve the soil nutrient supply capacity and utilization efficiency. This study could be helpful for the nutrient management and sustainable management of Chinese prickly ash orchards in the Guizhou karst mountainous area.
  • DownLoad:Evaluation of soil quality of Chinese prickly ash artificial orchard at different altitudes in Guizhou karst mountainous area.PDF
  • Effects of freeze-thaw cycles on soil microbial biomass carbon, nitrogen, and nitrogen mineralization in three types of forest in the temperate zone
  • Authors:GAO Shan, YIN Hang, FU Minjie, WU Minggen, DONG Chuang and LI Long
  • Abstract:To understand the effect of freeze-thaw processes on organic nitrogen conversion in forest soil, the upper layer and lower layer of soil in three types of forest in the temperate zone (hardwood broad-leaved forest, Korean pine broad-leaved forest, and secondary birch forest in the Changbai Mountains) were selected to study the dynamic changes in microbial biomass and soil available nitrogen after indoor freeze-thaw experiments (-15-5℃). The contents of soil microbial biomass carbon (SMBC) and the soil microbial biomass nitrogen (SMBN) in the upper soil layer of three forests were, in most cases, higher than in the control treatment (soil incubated at 5℃ for 4 days; recorded as CK) during the freeze-thaw period. The SMBC and SMBN in the upper soil layer of the three forest types were significantly higher than those in the lower soil layer (P < 0.05) subjected to freeze-thaw cycles and showed no obvious spatial heterogeneity. The effect of the freeze-thaw process on the content of NO3--N in soil was not clear. There was no significant difference (P > 0.05) in the soil NO3--N content between different freeze-thaw cycles at the same layer in each forest type. The NH4+-N content of the upper soil layer in three forest types showed similar trends with the frequency of freeze-thaw cycles, with obvious NH4+-N release characteristics in the third, fourth, and fifth freeze-thaw cycles. The responses of nitrogen mineralization (nitrification) in the three forest soils to the freeze-thaw process were clear. The temperature of the freeze-thaw, the frequency of the freeze-thaw cycles, and soil layer significantly affected the net nitrification rate and the net nitrogen mineralization rate. The net nitrification rate of the three forest soils fluctuated greatly. The net nitrification rate peaked in the upper layer after the second freeze-thaw cycle, followed by the seventh and the fifth freeze-thaw cycles. The soil net nitrification rate and net nitrogen mineralization rate in the upper layer of the three types of forests reached a peak for short-term freeze-thaw cycles and then followed a decreasing trend.
  • DownLoad:Effects of freeze-thaw cycles on soil microbial biomass carbon, nitrogen, and nitrogen mineralization in three types of forest in the temperate zone.PDF
  • Effects of film mulching on soil aggregations and organic carbon contents in Northern dryland regions
  • Authors:LIU Xiu, SI Pengfei, ZHANG Zhe, CHEN Baoqing, DONG Wenyi, YAN Changrong and LIU Enke
  • Abstract:Studying the effects of film mulching on soil aggregate stability and soil organic carbon distribution in different aggregate fractions can provide a scientific basis for exploring proper practices to improve the productivity and protect the environment in dryland farming. A long-term field experiment has been conducted in Fuxin, Liaoning province since 2012. Three treatments were carried out:non-mulching (CK), autumn plastic film mulching (AP), and spring plastic film mulching (SP). The soil aggregate and soil organic carbon (SOC)contents of different aggregates (> 2, 0.25-2, 0.053-0.25, and < 0.053 mm)in 0-10 and 10-20 cm soil layers were measured using a wet sieving method. Our results showed that long-term plastic film mulching significantly affected the soil aggregate size distribution, aggregate stability, and organic carbon content in the 0-10 cm soil layer, especially under AP while there was no significant difference among treatments in the 10-20 cm soil layer. Compared to CK, the amounts of > 2 mm water-stable aggregates under AP and SP significantly increased by 36.3% and 26.7%, respectively. However, no obvious difference was observed in micro-aggregates. These results suggested that plastic film significantly affected the stability of soil aggregates and accumulation of aggregate into macro-aggregates. The mean weight diameter value of water-stable aggregate was significantly higher in AP and SP than in CK at 0-10 cm soil layer. Compared to CK, AP and SP significantly increased the total SOC contents and SOC in the aggregates > 2 mm in size at the 0-10 cm soil layer, increased by 8.2% and 47.9% as well as 4.6% and 29.2% (P < 0.05), respectively. The contribution rate of the > 2 mm aggregate in total SOC was obviously increased by 37% and 26.1% in AP and SP (P < 0.05), respectively. However, in the 0-10 and 10-20 cm soil layers, the SOC in the micro-aggregates (0.053-0.25, < 0.053 mm)did not significantly affect the contribution rate of total organic carbon. The results indicated that film mulching promoted the accumulation of aggregates into macro-aggregates. Under the soil and planting conditions in Liaoning, Autumn plastic film mulching can improve the stability of 0-10 cm soil water-stable aggregates and increase the SOC contents of macro-aggregates, as well as further promote the sequestration of organic carbon.
  • DownLoad:Effects of film mulching on soil aggregations and organic carbon contents in Northern dryland regions.PDF

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