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A primary goal of studying climate change adaptation is to identify the adaptation options that are used to improve crop productivity or reduce the negative impacts of climate change. Many of the adjustments in farm management that farmers adopt do not necessarily represent true adaptations to climate change, an issue often ignored in existing literature and resulting in a risk that policy makers are misled to think that adaptation is easier than it actually is, and thereby underestimate the challenge that climate change presents. The overall goal of this study is to identify whether farmers’ adoptions are enhancing food production and adapting to climate change. The identification uses a plot-level panel from a survey of 619 rural households in three provinces in China and county-level weather data. With the use of plot and county-by-year fixed effects as well as instrumental variable approaches, our estimates show that the autonomous adoptions are not effective in improving crop yields. This implies that farmers’ adoptions cannot be always considered adaptations to climate change. The paper provides a possible explanation for the results and concludes with policy implications. [ABSTRACT FROM AUTHOR]

The dynamic response of groundwater level is examined in traverse and lengthways directions. Take the Yinsu section for an example, we have simulated groundwater levels before and after water-conveyance every time and calculated the incidence of groundwater on the both sides of the river. It is noted that the effect keeps growing with the water-delivery times increasing, from 570 m after the first times to 3,334 m after the eighth times. In addition, this paper involves the temporal response of the natural vegetation to water conveyance, vegetation coverage, planted-species number, dominant position and species diversity from 2002 to 2006. The findings indicate that the positive influence of ecological water conveyance project (EWCP) on the ecosystem in the Lower Tarim River is a long-term process. In this paper, we try to calculate water required for recovery of damaged ecosystem by using data available. This project is likely the base of research on water demand and the reference of measures for research on ecological water conveyance effect. [ABSTRACT FROM AUTHOR]

Remote sensing is a cost-effective tool for assessing vegetation damage by typhoon events at various scales. Taking Xiamen Island, southeastern China, as a study case, this paper aimed to assess and analyze the vegetation damage caused by Typhoon Meranti landfalling on September 15, 2016, using two high spatial resolution remote sensing images before and after the typhoon event. Seven severely damaged vegetation regions were selected based on the classification of vegetation types and visual interpretation of the images. Regression analysis was used to correct seasonal variation of the two high-solution images before and after typhoon. The vegetation area of the whole of Xiamen Island and the selected seven regions before and after typhoon were then calculated, respectively. Two spectral vegetation indicators, normalized difference vegetation index (NDVI) and fractional vegetation coverage (FVC), were also retrieved for the whole island and the seven regions. By comparing the difference in NDVI values before and after the typhoon of the two high spatial resolution images, we analyzed the most affected vegetation areas, as well as the most seriously damaged vegetation species. The typhoon has caused a decrease in vegetation area by 95.1 ha across the whole Xiamen Island. The mean NDVI and FVC decreased by 0.209 and 13 percentage points, respectively. While, in the seven selected severely damaged areas, the mean NDVI decreased by 0.356-0.444 and FVC decreased by 27-42 percentage points. The visual inspection showed that the tone of typhoon-damaged vegetation became darker, the patches of damaged vegetation became smaller and more fragmented, and the gap between vegetation canopies became larger. The most affected vegetation areas occurred in the southeastern hilly area, Jinshang and Hubin South Roads, as well as the Wuyuan Bay area. The most seriously damaged vegetation type is broad-leaved trees, especially the species, Acacia confusa, Delonix regia, Bauhinia variegata, Chorisia speciosa, Ficus benjamina and F. Concinna. [ABSTRACT FROM AUTHOR]

Urban forest soil infiltration, affected by various factors, is closely related with surface runoff. This paper studied the effect of urban forest types, vegetation configuration and soil properties on soil infiltration. In our study, 191 typical plots were sampled in Changchun City, China to investigate the soil infiltration characteristics of urban forest and its influencing factors. Our results showed that the steady infiltration rates of urban forest soil were highly variable. High variations in the final infiltration rates were observed for different vegetation patterns and compaction degrees. Trees with shrubs and grasses had the highest infiltration rate and trees with bare land had the lowest infiltration rate. In addition, our results showed that the soil infiltration rate decreased with an increase in the bulk density and with a reduction in the soil organic matter content and non-capillary porosity. The soil infiltration rate also had significantly positive relationships with the total porosity and saturated soil water content. Urban soil compaction contributed to low soil infiltration rates. To increase the infiltration rate and water storage volume of urban forest soil, proper techniques to minimize and mitigate soil compaction should be used. These findings can provide useful information for urban planners about how to maximize the water volume of urban forest soil and decrease urban instantaneous flooding. [ABSTRACT FROM AUTHOR]

Drought has become the most severe natural disaster in many provinces of China. In this paper, evaporative drought index (EDI) has been used to monitor China's surface dryness conditions based on the exponential evapotranspiration (ET) model and Hargreaves equation from JAXA-MODIS Insolation products, GEWEX, NCEP-2 and MODIS NDVI data. The exponential ET model based on the surface net radiation, vegetation index, mean air temperature and diurnal air temperature range (DTaR) has been developed to estimate surface ET of China and has been independently validated using ground-measured data collected from two sites (Arou and Miyun) in China, indicating that the bias varies from −5.96 to 5.02 W/m. The good agreement between daily estimated and ground-measured ET using ground observation data collected from all 22 sites further supports the validity of the exponential ET model for regional ET estimation. Moreover, EDI is closely correlated to the average soil moisture at 0-10 cm soil depth of the Yongning site with coefficient of determination of R = 0.52. The spatio-temporal patterns of monthly ET and EDI from April to September of 2004 over China are explored and the result indicates EDI is accordant with the precipitation by comparing the 15-day smoothed EDI with precipitation over six representative sites. The EDI based on the exponential ET model by integrating energy fluxes in response to soil moisture stress has demonstrated its validity for monitoring China's surface drought events. [ABSTRACT FROM AUTHOR]

This paper aims at detecting the relationships between phytogeographical patterns of genera of Chinese endemic seed plants and latitude or climatic factors. The landmass of China was divided into four latitudinal zones, each of c. 8°. Based on a total of 1664 indigenous genera of Chinese endemic seed plants which were grouped into fifteen geographical elements, belonging to three major categories (cosmopolitan, tropical and temperate) and which were absent or present in 28 provinces in China, we analyzed the phytogeographical patterns of genera of Chinese endemic seed plants and detected the relationships between them and main climatic factors. Our results showed that the proportion of tropical genera decreases with the increase in latitude; the proportion of temperate genera increases with the increase in latitude; and the proportion of cosmopolitan genera increased gradually increased gradually with latitude. There are a slow decrease in the proportion of tropical genera and slow increase in the proportion of temperate genera at latitudes 35°-40°. Alternatively, the tropical genera and the temperate genera have the same proportion at latitude c. 25°. These changes and issues about the different genera also appeared in main climate factors. In general, the genera present in a more northerly flora are a subset of the genera present in a more southerly flora. In summary, the large-scale patterns of phytogeography of endemic flora in China are strongly related to latitude, which covary with several climatic variables such as temperature. [ABSTRACT FROM AUTHOR]

China is the largest wheat-producing country in the world. Wheat is one of the two major staple cereals consumed in the country and about 60% of Chinese population eats the grain daily. To safeguard the production of this important crop, about 85% of wheat areas in the country are under irrigation or high rainfall conditions. However, wheat production in the future will be challenged by the increasing occurrence and magnitude of adverse and extreme weather events. In this paper, we present an analysis that combines outputs from a wide range of General Circulation Models (GCMs) with observational data to produce more detailed projections of local climate suitable for assessing the impact of increasing heat stress events on wheat yield. We run the assessment at 36 representative sites in China using the crop growth model CSM-CropSim Wheat of DSSAT 4.5. The simulations based on historical data show that this model is suitable for quantifying yield damages caused by heat stress. In comparison with the observations of baseline 1996-2005, our simulations for the future indicate that by 2100 the projected increases in heat stress would lead to an ensemble-mean yield reduction of −7.1% (with a probability of 80%) and −17.5% (with a probability of 96%) for winter wheat and spring wheat, respectively, under the irrigated condition. Although such losses can be fully compensated by CO fertilization effect as parameterized in DSSAT 4.5, a great caution is needed in interpreting this fertilization effect because existing crop dynamic models are unable to incorporate the effect of CO acclimation (the growth-enhancing effect decreases over time) and other offsetting forces. [ABSTRACT FROM AUTHOR]

Warming of the climate system is unequivocal, and the change of climate variables will eventually have a great impact on vegetation cover and agricultural practices, especially in the arid area Xinjiang in China, whose agriculture and ecosystems are heavily vulnerable to climate change. In this paper, normalized difference vegetation index (NDVI) was used to study the vegetation growth and its response to climate change in Xinjiang. Firstly, two NDVI datasets (Global Inventory Modeling and Mapping Studies (GIMMS) and Moderate Resolution Imaging Spectroradiometer (MODIS)) were merged through a pixel-wise regression analysis to obtain a long time series of NDVI data, and then, relationships between yearly NDVI and yearly climate variables, and monthly NDVI and monthly climate variables were extensively investigated for grassland and cropland in northern and southern Xinjiang, respectively. Results show the following: (1) there was an increasing trend in NDVI for both grassland and cropland in both northern and southern Xinjiang over the past decades and trends were significant except that for grassland in northern Xinjiang; (2) precipitation and evaporation were more important than temperature for grassland in northern Xinjiang, while precipitation and temperature were more important than evaporation for grassland in southern Xinjiang and cropland in both northern and southern Xinjiang; (3) NDVI was highly correlated with accumulated monthly precipitation instead of monthly precipitation, and there was a lagged effect of precipitation, temperature, and evaporation on NDVI change. However, lagged effects were only significant in specific months. The results could be helpful to agricultural practices; e.g., based on lagged effect of precipitation, irrigation in July is very important for crop growth. [ABSTRACT FROM AUTHOR]

Monitoring air pollution at a city scale is essential for controlling urban air pollution in cities, especially megacities, in China. In this paper, data for 1 city center site and 5 paired (stands and non-forested) PM monitoring sites across urban-rural areas in Beijing were collected, and air PM and influential factors were analyzed. The results showed that the mean value of PM (February to December 2013) was lower in the stands (67.00 μg m) than in the non-forested sites (78.02 μg m). The diurnal variation was a bimodal double-dip type, and the average daily PM was lower in the vegetation areas than in the non-vegetation areas in both Changping Dingling (vegetation) and Changping town (non-vegetation) and showed day > night. In the typical pollution process, accompanied by an increase or decrease in PM and air quality index values, the higher the PM, the lower the wind speed. PM in the vegetation areas lagged behind PM in the non-vegetation areas on typical sunny days but not on typical rainy and windy days. On typical sunny days, the variation of PM in the vegetation areas was less than that in the non-vegetation areas. PM did not change significantly under rainy conditions and before a rain, but the variation was smaller after a rain under the typical rainfall process; under typical windy conditions, the variation was not significant. Therefore, in the typical pollution process and under typical weather conditions, the annual and diurnal variations of PM were smaller in the vegetation areas than in the non-vegetation areas. The above results confirm that the forest has a strong ability to purify air and absorb PM particulate matter and that the air quality in vegetation areas is better than the air quality in non-forested areas. [ABSTRACT FROM AUTHOR]

This paper documents a 7800-year proxy record from the Shenjiadian peatland on the Sanjiang Plain in Northeast China. High-resolution plant macrofossil and colorimetric humification methods were used to reconstruct the vegetation and hydrologic history from a 193 cm-long sedimentary profile. Detrended correspondence analysis (DCA) was applied to transform the raw plant macrofossil data into latent indices of peatland water level. The vegetation community transited from an Equisetum fluviatile community to a Carex lasiocarpa community at approximately 3800 cal yr BP and was followed by a Carex-shrub community at approximately 480 cal yr BP. Based on the plant macrofossil DCA axis 1 scores and humification values, we distinguished four hydrologic periods: a wet period from 7800 cal yr BP to 4500 cal yr BP, dry periods up to 1600 cal yr BP, drier periods until 300 cal yr BP, and the driest period from 300 cal yr BP until the present. Through a comparison with other climate records, we suggest that the East Asian summer monsoon (EAM) was the main driving force for vegetation and water level changes to the Shenjiadian peatland through its impacts on precipitation. [ABSTRACT FROM AUTHOR]

The ecological structure in the arid and semi-arid region of Northwest China with forest, grassland, agriculture, Gobi, and desert, is complex, vulnerable, and unstable. It is a challenging and sustaining job to keep the ecological structure and improve its ecological function. Net primary productivity (NPP) modeling can help to improve the understanding of the ecosystem, and therefore, improve ecological efficiency. The boreal ecosystem productivity simulator (BEPS) model provides the possibility of NPP modeling in terrestrial ecosystem, but it has some limitations for application in arid and semi-arid regions. In this paper, we improve the BEPS model, in terms of its water cycle by adding the processes of infiltration and surface runoff, to be applicable in arid and semi-arid regions. We model the NPP of forest, grass, and crop in Gansu Province as an experimental area in Northwest China in 2003 using the improved BEPS model, parameterized with moderate resolution remote sensing imageries and meteorological data. The modeled NPP using improved BEPS agrees better with the ground measurements in Qilian Mountain than that with original BEPS, with a higher R of 0.746 and lower root mean square error (RMSE) of 46.53 gC m compared to R of 0.662 and RMSE of 60.19 gC m from original BEPS. The modeled NPP of three vegetation types using improved BEPS shows evident differences compared to that using original BEPS, with the highest difference ratio of 9.21 % in forest and the lowest value of 4.29 % in crop. The difference ratios between different vegetation types lie on the dependence on natural water sources. The modeled NPP in five geographic zones using improved BEPS is higher than those with original BEPS, with higher difference ratio in dry zones and lower value in wet zones. [ABSTRACT FROM AUTHOR]

Understanding the seasonal behaviour of a subtropical forest and its inter-annual variation is crucial to understanding and monitoring its ecosystem function in the context of global warming. Based on the Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index dataset, a wavelet transform method was used to investigate the inter-annual variations of vegetation phenology in a subtropical mountain and hill region in Fujian, China, during 2001-2010. The results show a distinct inter-annual variation of vegetation phenology related to climate variability even if most areas presented non-significant trends. The start dates significantly advanced and end dates delayed in 2003 and 2008, due to anomalously warm conditions. There was generally a gradient of increasing start dates, and earlier end dates of vegetation growing season, due to colder temperatures at higher altitudes. However, the altitudinal phenology relationship also depends on its corresponding rainfall conditions. Earlier start dates were observed at higher altitudes during rainfall deficit years such as 2008, which coincides with relatively abundant rainfall at higher altitudes. This paper reveals that vegetation phenology was coupled with altitudinal gradient, with distinct responses at different combinations of alternate temperature and precipitation conditions variability. [ABSTRACT FROM AUTHOR]

To overcome the shortcoming of existing studies, this paper put forward a statistical vegetation-climate relationship model with integrated temporal and spatial characteristics. Based on this model, we quantitatively discriminated on the grid scale the relative role of climate change and human activities in the desertification dynamics from 1986 to 2000 in Yulin region. Yulin region's desertification development occurred mainly in the southern hilly and gully area and its reverse in the northwest sand and marsh area. This spatial pattern was especially evident and has never changed thoroughly. From the first time section (1986-1990) to the second (1991-1995), the desertification was developing as a whole, and either in the desertification development district or in the reverse district human activities' role was always occupying an overwhelmingly dominant position (they were 98.7% and 101.4%, respectively), the role of climate change was extremely slight. From the second time section (1991-1995) to the third (1996-2000), the desertification process was reaching a state of stability, in the desertification development district the role of climate change was nearly equivalent to that of human activities (they were 46.2% and 53.8% separately), and yet in the desertification reverse district, the role of human activities came up to 119.0%, the role of climate change amounted to −19.0%. In addition, the relative role of climate change and human activities possessed great spatial heterogeneity. The above conclusion rather coincides with the qualitative analysis in many literatures, which indicates that this method has certain rationality and can be utilized as a reference for the monitoring and studying of desertification in other areas. [ABSTRACT FROM AUTHOR]

Based on SPOT-VGT images and meteorological data, this paper applied an integrated method to investigate the vegetation dynamic and its response to climate factors during 1998-2008 in Northeast China Transect, one of 15 ecological transects listed in the International Geosphere-Biosphere Programme. The main findings are as follows: (1) The NDVI time series presented nonlinear patterns that vary with timescales. The series fluctuated greatly at the smallest timescale (20 days), showing no salient trend, whereas a trend manifested itself more and more with the increase of time scale and finally stabilized at the 320-day scale. Little difference was found between vegetation types about the NDVI periodicity, as they occurred on either a 280-day or a 290-day cycle. (2) NDVI exhibited a significant correlation with temperature, precipitation, and sunshine hours. Overall, the correlation between NDVI and temperature was the highest, followed by precipitation, sunshine hours, and relative humidity. For different vegetation types, the correlations between NDVI and climate variables diversified, increasing from desert steppe to typical steppe, meadow steppe, and forest. (3) The periodicity of temperature and precipitation occurred in either a 280-day or 290-day cycle, which was approximately coincident with that of NDVI. This further supported the significant relationship between NDVI and these two climate factors. (4) At all the time scales under examination, NDVI and temperature and precipitation are significantly, positively correlated, especially at the 160-day scale, which can be regarded as the most suitable time scale for investigating the responses of vegetation dynamics to climate factors at most stations. [ABSTRACT FROM AUTHOR]

The pollen and spores of the Wuyun Formation (Danian, Early Paleocene) from Jiayin County, Heilongjiang Province, Northeast China, are studied in this paper. The Danian vegetation at Wuyun was composed of mixed temperate and subtropical broad-leaved forest, with an admixture of conifers. The climatic parameters, obtained by the Coexistence Approach based on the palynological and megafossil data, are Mean Annual Temperature of 14.8–16.8°C, Mean Annual Precipitation of 815.8–1,571.8 mm. Combining other climatic parameters in the Tertiary, we obtained the latitudinal temperature gradients: 0.24 in Paleocene, 0.1 in Eocene, 0.45 in Miocene and 0.55 in Pliocene, in the area of East Asia. All these values and modern latitudinal gradient of 0.7 suggest a climatic transition from Paleocene to today: the temperature at higher latitudes first increased then decreased gradually during last 65 Ma, while it changed slightly in lower latitudes. [ABSTRACT FROM AUTHOR]

Green plants play an important role in energy flows and material cycles. The net primary productivity (NPP) reflects the capability of vegetation to convert solar energy into photosynthate (fixed carbon). Understanding the factors that contribute to variations in NPP is of key importance for improving the rock-desertification environment in karst areas. In this paper, the NPP model (Light Use Efficiency model) is modified on the basis of remote sensing data [moderate resolution imaging spectroradiometer (MODIS)], climate data and observed information. Then the model is employed to estimate the spatial–temporal variations of NPP in the Guizhou Province, China. Finally, the NPP differences between karst area and non-karst area, and the relationships between NPP and climate factors are analyzed. The results show that the NPP estimated using MODIS data are reasonable. The mean NPP of territorial vegetation is 421.46 gC m−2 year−1; the NPP in the non-karst area is 13.3% higher than that in the karst area; the correlation degree between NPP and precipitation is better in southeastern and western districts. [ABSTRACT FROM AUTHOR]

In this paper, temporal dynamics of eco-environmental changes in coastal areas of China during 1981–2000 are investigated based on four key surface parameters including normalized difference vegetation index (NDVI), thermal index, moisture index and surface broadband albedo derived from quantitative remote sensing techniques and meteorological data. Firstly, land surface temperature (LST) and land surface broadband albedo are retrieved by the split-window algorithms and high-order polynomial regression method, respectively, using NOAA/AVHRR series images. Then, moisture index and thermal index, indicators of climate and moisture conditions in the study area, are computed from meteorological data and LST using principal component analysis (PCA). Finally, long-term dynamics of these eco-environmental factors and the reasons responsible for these changes are analyzed further. The results show that during the years from 1981 to 2000, the study area experienced a gradual increase in annual NDVI and climate factors and a decrease in surface annual broadband albedo, which indicates that the coastal thermal and moisture conditions and the subsistence conditions of natural vegetation have changed to a considerable extent. According to the results, a warming and wetting tendency over the last two decades is obvious in the China’s coastal zone that are mainly due to land use changes as of growing urbanization, exhaust emissions from industries and transportations and, partly global climate change. Uncontrolled rapid development of the study area may be blamed for these negative changes as a major driving force. The positive feedback mechanisms between albedo, NDVI and climate factors also partly explain these changes. This study suggests that the method integrating biophysical parameters retrieved from remote sensed images and meteorologic data provides a novel and feasible way to monitor large scale eco-environmental changes. [ABSTRACT FROM AUTHOR]

This paper presents a multi-proxy reconstruction of the climate change in Caotanhu wetland using pollen, phytolith and charcoal records, and the data of loss of ignition (LOl), grain size analysis, and susceptibility. Results reveal that between 4550 and 2500 cal. a BP, a dry climatic condition was not favorable for the accumulation of peat. Since 2500 cal. a BP, the climate became humid and the wetland developed with abundant freshwater aquatic plants, which contributed to peat accumulation. Nevertheless, alternate periods of rain and dry climate occurred during that period. Between 2500 and 1810 cal. a BP (550 BC-140 AD), the climate was more humid than at present. A lot of emerged plants, such as Phragmites, Typha and Sparganium, and freshwater green algae grew in the wetland which was surrounded by desert-steppe vegetation composed mainly of Chenopodiaceae, Artemisia, Compositae and Thalictrum. However, from 1810 to 1160 cal. a BP (140-790 AD), the water level started to decrease and hydrophyte species reduced greatly, but some Phragmites still grew in the wetland and around it was desert vegetation with high proportion of Chenopodiaceae and Artemisia. Then from 1160 to 650 a BP (790-1300 AD), it entered a period of desert-steppe with abundant mesic and xerophytic plants. And a lot of aquatic plants prevailed in the wetland. Here, what is noticeable is that percentages of arboreal pollen, consisting mainly of Betula and Picea, increased greatly and reached a maximal value of 27.2%, in which, Betula percentages rose to 23.2%. Hence, it is reasonable to conclude that Betula grew in the highland of the wetland, or Picea timberline shifted downward resulting in the increase of percentages of Betula and Picea pollen, which were transported into the wetland by flood or wind. But since 650 cal. a BP, desert vegetation prevailed around the wetland again with dominant Chenopodiaceae and Artemisia, and the climate was similar to modern one. Despite some aquatic plants still growing in the wetland at that time, their amounts diminished greatly. [ABSTRACT FROM AUTHOR]

Recent climatic changes have affected terrestrial net primary productivity (NPP). This paper presents an investigation of the impact of climatic changes on Chinese terrestrial vegetation NPP by analyzing 18 years' (1982 to 1999) climatic data and satellite observations of vegetation activity. Results indicate that climatic changes in China have eased some critical climatic constraint on plant growth. (1) From 1982 to 1999, modeled NPP increased by 1.42% · a-1 in water-limited regions of Northwest China, 1.46% · a-1 in temperature-limited regions of Northeast China and Tibet Plateau, and 0.99% · a-1 in radiation-limited regions of South China and East China. (2) NPP increased by 24.2%, i.e. 0.76 petagram of carbon (Pg C) over 18 years in China. Changes in climate (with constant vegetation) directly contributed nearly 11.5% (0.36 Pg C). Changes in vegetation (with constant climate) contributed 12.4% (0.40 Pg C), possibly as a result of climate-vegetation feedbacks, changes in land use, and growth stimulation from other mechanisms. (3) Globally, NPP declined during all three major El Niño events (1982 to 1983, 1987 to 1988, and 1997 to 1998) between 1982 and 2000, but Chinese vegetation productivity responded differently to them because of the monsoon dynamics. In the first three events (1982 to 1983, 1987 to 1988, and 1992), Chinese vegetation NPP declined, while in the later two events (1993, 1997 to 1998) increasing obviously. [ABSTRACT FROM AUTHOR]

This paper applies climate change scenarios in China based on the SRES assumptions with the help of RCMs projections by PRECIS (providing regional climates for impacts studies) system introduced to China from the Hadley Centre for Climate Prediction and Research at a high-resolution (50 km×50 km) over China. This research focuses on B2 scenario of SRES. A biogeochemical model "Atmosphere Vegetation Integrated Model (AVIM2)" was applied to simulating ecosystem status in the 21st century. Then vulnerability of ecosystems was assessed based on a set of index of mainly net primary production (NPP) of vegetation. Results show that climate change would affect ecosystem of China severely and there would be a worse trend with the lapse of time. The regions where having vulnerable ecological background would have heavier impacts while some regions with better ecological background would also receive serious impacts. Extreme climate even would bring about worse impact on the ecosystems. Open shrub and desert steppe would be the two most affected types. When the extreme events happen, vulnerable ecosystem would extend to part of defoliate broad-leaved forest, woody grassland and evergreen conifer forest. Climate change would not always be negative. It could be of some benefit to cold region during the near-term. However, in view of mid-term to long-term negative impact on ecosystem vulnerability would be enormously. [ABSTRACT FROM AUTHOR]

Estimates of forest vegetation carbon storage in China varied due to different methods used in the assessments. In this paper, we estimated the forest vegetation carbon storage from the Fourth Forest Inventory Data (FFID) in China using a modified volume-derived method. Results showed that total carbon storage and mean carbon density of forest vegetation in China were 3.8 Pg C (about 1.1% of the global vegetation carbon stock) and 41.32 Mg/ha, respectively. In addition, based on linear multiple regression equation and factor analysis method, we analyzed contributions of biotic and abiotic factors (including mean forest age, mean annual temperature, annual precipitation, and altitude) to forest carbon storage. Our results indicated that forest vegetation carbon storage was more sensitive to changes of mean annual temperature than other factors, suggesting that global warming would seriously affect the forest carbon storage. [ABSTRACT FROM AUTHOR]

The ratio of plant transpiration to total terrestrial evapotranspiration (T/ET) captures the role of vegetation in surface-atmosphere interactions. However, several studies have documented a large variability in T/ET. In this paper, we present a new T/ET dataset (also including transpiration, evapotranspiration data) for China from 1981 to 2015 with spatial and temporal resolutions of 0.05° and 8 days, respectively. The T/ET dataset is based on a model-data fusion method that integrates the Priestley-Taylor Jet Propulsion Laboratory (PT-JPL) model with multivariate observational datasets (transpiration and evapotranspiration). The dataset is driven by satellite-based leaf area index (LAI) data from GLASS and GLOBMAP, and climate data from the Chinese Ecosystem Research Network (CERN). Observational annual T/ET were used to validate the model, with R2 and RMSE values were 0.73 and 0.07 (12.41%), respectively. The dataset provides significant insight into T/ET and its changes over the Chinese terrestrial ecosystem and will be beneficial for understanding the hydrological cycle and energy budgets between the land and the atmosphere. Measurement(s) ratio of transpiration to total terrestrial evapotranspiration • evapotranspiration • transpiration Technology Type(s) model-data fusion • computational modeling technique • digital curation Factor Type(s) year of data collection Sample Characteristic - Environment terrestrial biome Sample Characteristic - Location China Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12917642 [ABSTRACT FROM AUTHOR]

Dynamic change of vegetation in northern China from 1998–2007 was explored, based on SPOT-VGT data. The results showed that the NDVI can effectively monitor vegetation change, but also the mean multi-year NDVI maximum of 0.10 basically can be considered as the threshold of vegetation cover in northern China, and those places with smaller than or equal to the threshold value mainly were covered by deserts, Gobi and lakes, salinization lands, glaciers, snow patches and bare mountains, etc. The change trends of vegetation where sub-region C and D were affected by east-Asia monsoon were similar with the characteristics of first decreasing, later increasing and finally slowly decreasing; the difference lies in that sub-region C maintained a lower vegetation state, and sub-region D reached a higher state. The vegetation change of sub-region A was anomalous with smaller fluctuation. The change trend of vegetation of sub-region B was not only extremely unstable, but also the change extent was huge. As far as the whole of northern China is concerned, vegetation has not demonstrated obvious improvement since these ecological construction and protection projects, and the area of vegetation degradation still is much larger than that of vegetation improvement from 1998 to 2007, but there was a bigger spatial difference. Field investigation and remote sensing monitoring reveal that vegetation has obviously been improved in the agro-grazing mixing zone and to the south, as well as many oases in the northwestern arid zone, while vegetation still has worsened in the steppes, especially the Ulanqab steppe, Hunshandake Sandy Land, the region along the Sino–Mongolia border within Xilingol Meng, Hulunbeir Sandy Land and the northern Tianshan mountain region in Xinjiang. Human activities only obviously showed success in local regions. The compelling challenges of restoring the eco-environment are still immense, especially in the northern grazing zone of China. [ABSTRACT FROM AUTHOR]

Observed data showed the climatic transition from warm-dry to warm-wet in Xinjiang during the past 30 years and will probably affect vegetation dynamics. Here, we analyze the interannual change of vegetation index based on the satellite-derived normalized difference vegetation index (NDVI) with temperature and precipitation extreme over the Xinjiang, using the 8-km NDVI third-generation (NDVI3g) from the Global Inventory Modelling and Mapping Studies (GIMMS) from 1982 to 2010. Few previous studies analyzed the link between climate extremes and vegetation response. From the satellite-based results, annual NDVI significantly increased in the first two decades (1981–1998) and then decreased after 1998. We show that the NDVI decrease over the past decade may conjointly be triggered by the increases of temperature and precipitation extremes. The correlation analyses demonstrated that the trends of NDVI was close to the trend of extreme precipitation; that is, consecutive dry days (CDD) and torrential rainfall days (R24) positively correlated with NDVI during 1998–2010. For the temperature extreme, while the decreases of NDVI correlate positively with warmer mean minimum temperature (Tnav), it correlates negatively with the number of warmest night days (Rwn). The results suggest that the climatic extremes have possible negative effects on the ecosystem. [ABSTRACT FROM AUTHOR]

Traditionally, the evaluation of pollen-based quantitative paleoclimate reconstructions focuses on the ability of calibration sets to infer present climatic conditions and/or the similarity between fossil and modern assemblages. Objective criteria for choosing the most appropriate climate parameter(s) to be reconstructed at a specific site are thus lacking. Using a novel approach for testing the statistical significance of a quantitative reconstruction using random environmental data, in combination with the advantageous large environmental gradients, abundant vegetation types and comprehensive modern pollen databases in China, we describe a new procedure for pollen-based quantitative paleoclimatic reconstructions. First, the most significant environmental variable controlling the fossil pollen assemblage changes is identified. Second, a calibration set to infer changes in this targeted variable is built up, by limiting the modern ranges of other environmental variables. Finally, the pollen-based quantitative reconstruction is obtained and its statistical significance assessed. This novel procedure was used to reconstruct the mean annual precipitation ( P ) from Gonghai Lake in the Lvliang Mountains, and Tianchi Lake in the Liupan Mountains, on the eastern and western fringe of the Chinese Loess Plateau, respectively. Both P reconstructions are statistically significant ( p<0.001), and a sound and stable correlation relationship exists in their common period, showing a rapid precipitation decrease since 3300 cal yr BP. Thus, we propose that this procedure has great potential for reducing the uncertainties associated with pollen-based quantitative paleoclimatic reconstructions in China. [ABSTRACT FROM AUTHOR]

China's large population and deteriorating environment have created great concern related to the sustainability of food production, especially since details related to this topic remain poorly studied. Thus, an integrated analysis of both crop yield and cultivated area is essential for gaining a better understanding of cereal grain production in China and for making corresponding policies designed to achieve food security. In this study, we adopt trend analysis of both provincial yield and cultivated area to assess the subsequent provincial-level cereal production sustainability between 1980 and 2011 with the goal of providing a better understanding of regional agricultural development. The results indicate that while maize shows the most promise for yield improvement, rice and wheat production is experiencing substantial yield stagnation among most provinces across mainland China. In addition, the trends in spatial patterns are prominently different from those of yields. The sizes of the main rice- and wheat-growing areas in China have declined greatly, suggesting that the related production of these cereals should attract more attention from land management planners and farmers. Specifically, the south-eastern coastal provinces have largely failed to sustain both crop yield and area, while the north-eastern provinces have witnessed thriving agricultural production during the last three decades. Moreover, we find that cereal production in China is significantly affected by governmental policies related to the agricultural sector. Thus, this analysis of food production in China will help policymakers to better understand how the potential implications of food security in China may be applicable to countries worldwide. [ABSTRACT FROM AUTHOR]

The sensitivity of surface air temperature response to different grassland types and vegetation cover changes in the regions of temperate grassland of China was analyzed by observation minus reanalysis (OMR) method. The basis of the OMR approach is that reanalysis data are insensitive to local surface properties, so the temperature differences between surface observations and reanalysis can be attributed to land effects. Results showed that growing-season air temperature increased by 0.592 °C/decade in the regions of temperate grassland of China, with about 31 % of observed warming associated with the effects of grassland types and vegetation cover changes. For different grassland types, the growing-season OMR trend was the strongest for temperate desert steppe (0.259 °C/decade) and the weakest for temperate meadow (0.114 °C/decade). Our results suggest that the stronger intraseasonal changes of grassland vegetation are present, the more sensitive the OMR trend responds to the intraseasonal vegetation cover changes. In August and September, the OMR of temperate meadow showed a weak cooling trend. For temperate meadow, about 72.2 and 72.6 % of surface cooling were explained by both grassland type and increase of vegetation cover for August and September, respectively. For temperate steppe and temperate desert steppe, due to the limited soil moisture and little evaporative cooling feedback, the vegetation changes have no significant effect on the surface air temperature. These results indicate that the impact of grassland types and vegetation cover changes should be considered when projecting further climate change in the temperate grassland region of China. [ABSTRACT FROM AUTHOR]

Examining the direct and indirect effects of climatic factors on vegetation growth is critical to understand the complex linkage between climate change and vegetation dynamics. Based on the Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data and meteorological data (temperature and precipitation) from 2001 to 2012, the trend of vegetation dynamics were examined in the Ziya-Daqing basins, China. The path analysis was used to obtain the information on the relationships among climatic factors and their effects on vegetation growth. It was found that the trends of growing season NDVI were insignificant in most plain dry land, while the upward trends were significant in forest, grass and dry land in Taihang Mountains. According to the path analysis, in 23% of the basins the inter-annual NDVI variation was dominated by the direct effect of precipitation, in 5% by the direct effects of precipitation and temperature, and in less than 1% by the direct effect of temperature or indirect effects of these two climatic factors. It indicated that precipitation significantly affected the vegetation growth in the whole basins, and this effect was not regulated by temperature. Precipitation increase (especially in July, August and September) was favorable to greenness enhancement. Summer temperature rising showed negative effect on plant productivity enhancement, but temperature rise in April was beneficial for the vegetation growth. When April temperature increases by 1°C, the onset date of greenness for natural vegetation will be 2 days in advance. There was a lag-time effect of precipitation or temperature on monthly NDVI for all land use types except grass. [ABSTRACT FROM AUTHOR]

Litterfall plays an important role in carbon and nutrient cycling of a forest ecosystem which is generally affected by climate, vegetation, forest type and age. The majority of the subtropical forests of China are occurring in nutrient poor environment, and thus there is a need to understand the role of litterfall on the recycling of C and nutrients in these forests for their proper management. We measured litter production, and carbon and nutrient return in an evergreen broad-leaved primary forest (Mt. Ailao, SW China) and a deciduous broad-leaved secondary forest (Mt. Damei, East China). The annual litterfall productions were 1124 and 490 g m at the primary evergreen forest and secondary deciduous forest, respectively. Carbon return in primary evergreen forest was approximately three times greater than that in secondary deciduous forest. Litter N concentrations in the secondary deciduous forest were higher than that of the primary evergreen forest and consequently, the use efficiency of N of the secondary deciduous forest was lower than the primary evergreen forest. This reflects a stronger nutrient conservation mechanism in the primary evergreen forest than in the secondary forest. [ABSTRACT FROM AUTHOR]

The conservation of natural vegetation directly impacts biodiversity conservation; thus, it is important to evaluate the effectiveness of vegetation protection in nature reserve networks. In this study, ArcGIS 10.0 was used for gap analysis of terrestrial vegetation protection within the national nature reserve network in mainland China. Overall, 9.75 % of the land area was covered by 366 national nature reserves. The bias of the protection ratio was particularly obvious among the different vegetation regions, zones, provinces and districts. The warm temperate deciduous broadleaf forest region was the least protected (1.84 %), and most of the NNRs were located in the Qinghai-Xizang Plateau alpine vegetation region (35.8 %). Moreover, in most vegetation zones (57.14 %), less than 5 % of the area was protected, and in vegetation provinces and vegetation districts, 8.85 and 35.87 %, respectively, were not protected by national nature reserves. However, the number of national nature reserves could be higher in these vegetation zones, provinces and districts than in other areas. The protection bias became more significant as the analysis scale decreased. In addition, nearly 25 % of the natural formations in mainland China were unprotected by national nature reserves. A bias was also observed in the protection of different natural formations, with a lack or lower degree of protection for desert, grass-forb community, steppe, and scrub biomes, which were spread throughout northwest and eastern China. A distinct lack of protected areas was observed in certain parts of the country. Therefore, additional land may require protection in the vegetation provinces and districts in the Tianshan Mountains, Junggar Basin, West Kunlun Mountains, Loess Plateau, and karst districts in southwest Guangxi Province and along the southeast coast of China. [ABSTRACT FROM AUTHOR]

Vegetation communities in floodplain lakes are adapted to natural water regimes. Construction of sluices or dams between rivers and their floodplain lakes will inevitably lead to great changes in plant communities. In order to evaluate the effects of water level fluctuations (WLFs) on lakeshore vegetation in floodplain lakes of the Yangtze River, a field investigation was conducted in two river-disconnected lakes (Wuchang Lake and Shengjin Lake) and one river-connected lake (Shimen Lake). The results showed that plant species richness was highest in the disconnected Shengjin Lake with intermediate amplitude of WLFs, and lowest in the connected Shimen Lake. Species composition differed among the three lakes and the two disconnected lakes with more similar WLFs exhibiting the greatest similarity. Six plant communities were classified using TWINSPAN. Multivariate analyses showed that the amplitude of WLFs was the most important factor in determining the distribution of lakeshore plants, followed by relative elevation and duration of submergence. Our results provide an eco-hydrological basis for plant restoration in the Yangtze floodplain lakes. We suggest that fluctuating amplitude should be increased in lakes with small WLFs, and small habitats with various hydrological regimes should be created in lakes with large WLFs. [ABSTRACT FROM AUTHOR]

Fossil pollen records from 45 sites across China were evaluated and synthesized to document vegetation and climate change during Marine Isotope Stage 3 (MIS 3) at 60-27 ka and to understand the large-scale controls. During MIS3, vegetation type was dominantly forest in eastern China, forest steppe/meadow in the north and Tibetan Plateau, and steppe desert in northwestern arid China. We developed a semi-quantitative vegetation index to reflect change in plant abundance (by inferring the general climate conditions), with a vegetation score from 1 to 3 based on the different vegetation types inferred from pollen data at individual sites at intervals of 2,000 years. The reconstructed vegetation index shows higher values during MIS 3, especially during the period 53-40 ka, than at the Last Glacial Maximum. Our results also suggest that climate on the basis of vegetation change was cooler and drier during MIS 3 than during the Holocene optimum; however, MIS 3 vegetation was probably similar to modern vegetation. The close relationship between vegetation change, insolation and Asian summer monsoon strength suggests that climate variations, probably in both temperature and precipitation, are the primary drivers of regional vegetation change. Additional well-dated, high-resolution palaeoclimate records from many locations across China will be needed to understand the vegetation change and climate forcings on millennial and centennial scales within MIS 3. [ABSTRACT FROM AUTHOR]

Temperature has long been accepted as the major controlling factor in determining vegetation phenology in the middle and higher latitudes. The influence of water availability is often overlooked even in arid and semi-arid environments. We compared vegetation phenology metrics derived from both in situ temperature and satellite-based normalized difference vegetation index (NDVI) observations from 1982 to 2006 by an example of the arid region of northwestern China. From the satellite-based results, it was found the start of the growing season (SOS) advanced by 0.37 days year and the end of the growing season (EOS) delayed by 0.61 days year in Southern Xinjiang over 25 years. In the Tianshan Mountains, the SOS advanced by 0.35 days year and the EOS delayed by 0.31 days year. There were almost no changes in Northern Xinjiang. Compared with satellite-based results, those estimates based on temperature contain less details of spatial variability of vegetation phenology. Interestingly, they show different and at times reversed spatial patterns from the satellite results arising from water limitation. Phenology metrics derived from temperature and NDVI conclude that water limitation of onset of the growing season is more severe than the cessation. Phenology spatial patterns of four oases in Southern Xingjiang show that, on average, there is a delay of the SOS of 1.6 days/10 km of distance from the mountain outlet stations. Our results underline the importance of water availability in determining the vegetation phenology in arid regions and can lead to important consequences in interpreting the possible change of vegetation phenology with climate. [ABSTRACT FROM AUTHOR]

Climate plays a crucial role in controlling vegetation distribution and climate change may therefore cause extended changes. A coupled biogeography and biogeochemistry model called BIOME4 was modified by redefining the bioclimatic limits of key plant function types on the basis of the regional vegetation-climate relationships in China. Compared to existing natural vegetation distribution, BIOME4 is proven more reliable in simulating the overall vegetation distribution in China. Possible changes in vegetation distribution were simulated under climate change scenarios by using the improved model. Simulation results suggest that regional climate change would result in dramatic changes in vegetation distribution. Climate change may increase the areas covered by tropical forests, warm-temperate forests, savannahs/dry woodlands and grasslands/dry shrublands, but decrease the areas occupied by temperate forests, boreal forests, deserts, dry tundra and tundra across China. Most vegetation in east China, specifically the boreal forests and the tropical forests, may shift their boundaries northwards. The tundra and dry tundra on the Tibetan Plateau may be progressively confined to higher elevation. [ABSTRACT FROM AUTHOR]

Recent shifts in phenology reflect the biological response to current climate change. Aiming to enhance our understanding of phenological responses to climate change, we developed, calibrated and validated spatio-temporal models of first leaf date (FLD) for 20 broadleaved deciduous plants in China. Using daily meteorological data from the Chinese Meteorological Administration and the Community Climate System Model, version 3 (CCSM3) created using three IPCC scenarios (A2, A1B and B1), we described the FLD time series of each species over the past 50 years, extrapolating from these results to simulate estimated FLD changes for each species during the twenty-first century. Model validation suggests that our spatio-temporal models can simulate FLD accurately with R (explained variance) >0.60. Model simulations show that, from 1952 to 2007, the FLD in China advanced at a rate of −1.14 days decade on average. Furthermore, changes in FLD showed noticeable variation between regions, with clearer advances observed in the north than in the south of the country. The model indicates that the advances in FLD observed from 1952-2007 in China will continue over the twenty-first century, although significant differences among species and different climate scenarios are expected. The average trend of FLD advance in China during the twenty-first century is modeled as being −1.92 days decade under the A2 scenario, −1.10 days decade under the A1B scenario and −0.74 days decade under the B2 scenario. The spatial pattern of FLD change for the period 2011-2099 is modeled as being similar but showing some difference from patterns in the 1952-2007 period. At the interspecific level, early-leafing species were found to show a greater advance in FLD, while species with larger distributions tended to show a weaker advance in FLD. These simulated changes in phenology may have significant implications for plant distribution as well as ecosystem structure and function. [ABSTRACT FROM AUTHOR]

Knowledge of both vegetation distribution pattern and phenology changes is very important. Their complicated relationship with elevation and accessibility were explored through a geographically weighted regression (GWR) framework in Fujian province, China. The 16-day time series of 250 m Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) dataset from 2000 to 2010 was applied. Wavelet transform method was adopted to decompose the original time series and construct the annual maximum EVI and amplitude of the annual phenological cycle (Δ EVI). Candidate explaining factors included topographic conditions, accessibility variables and proportions of primary vegetation types. Results revealed very strong positive influence from parameters of elevation and accessibility to big rivers and negative effect from accessibility to resident on both maximum EVI and phenological magnitude through ordinary linear least square (OLS) regression analysis. GWR analysis revealed that spatially, the parameters of topography and accessibility had a very complex relationship with both maximum EVI and phenology magnitude, as a result of the various combinations of environmental factors, vegetation composition and also intensive anthropogenic impact. Apart from the continuously increasing trend of phenology magnitude with increasing altitude, the influence of topography and accessibility on maximum EVI and phenological magnitude generally decreased, even from strongly positive to negative, with increasing altitude or distance. Specially, the most rapid change of correlation coefficient between them was observed within a low elevation or close distance; less variation was discovered within a certain range of medium altitude or distance and their relationship might change above this range. Non-stationary approaches are needed to better characterize the complex vegetation dynamic pattern in Mountain-hill Region. [ABSTRACT FROM AUTHOR]

Vegetation in the upper catchment of Yellow River is critical for the ecological stability of the whole watershed. The dominant vegetation cover types in this region are grassland and forest, which can strongly influence the eco-environmental status of the whole watershed. The normalized difference vegetation index (NDVI) for grassland and forest has been calculated and its daily correlation models were deduced by Moderate Resolution Imaging Spectroradiometer products on 12 dates in 2000, 2003, and 2006. The responses of the NDVI values with the inter-annual grassland and forest to three climatic indices (i.e., yearly precipitation and highest and lowest temperature) were analyzed showing that, except for the lowest temperature, the yearly precipitation and highest temperature had close correlations with the NDVI values of the two vegetation communities. The value of correlation coefficients ranged from 0.815 to 0.951 ( p < 0.01). Furthermore, the interactions of NDVI values of vegetation with the climatic indicators at monthly interval were analyzed. The NDVI of vegetation and three climatic indices had strong positive correlations (larger than 0.733, p < 0.01). The monthly correlations also provided the threshold values for the three climatic indictors, to be used for simulating vegetation growth grassland under different climate features, which is essential for the assessment of the vegetation growth and for regional environmental management. [ABSTRACT FROM AUTHOR]

The passive cooling effect of green roofs in humid, tropical Hong Kong was investigated with reference to three vegetated plots, grass, groundcover herb, and shrub, with contrasting growth form and biomass structure and a bare control plot. Temperature was monitored at 15-min intervals for a year at seven levels: high (H) at 200 cm, middle (M) at 60 cm, low (L) at 20 cm, surface, soil, rockwool (water storage), and roof-tile surface. The findings indicated the crucial roles played by biomass quantity and structural complexity in passive cooling functions. Temperature variations of vegetated roofs occurred mainly during the day, with lower maximum and minimum than the control, but they did not cool air at night better than the control. Control and grass surfaces were warmed above the ambient temperature, but groundcover and shrub surfaces followed the ambient. Despite complex biomass structure, shrub created the most extreme diurnal air temperature regime. Despite simple biomass structure, grass cooled air more effectively than groundcover and shrub. Four anomalies in the vertical temperature profile were detected. First, the grass roof cooled daytime near-ground air to create a suspended temperature inversion. Second, the stagnant air within the shrub biomass trapped heat to generate a daytime canopy temperature inversion. Third, the elevated branch-foliage biomass of groundcover and shrub brought passive cooling to form a perched thermal discontinuity. Fourth, the air gap of the plastic drainage layer arrested downward heat transmission in all vegetated plots to form a subsurface thermal discontinuity. The findings provide hints on species choice and design of green roofs. [ABSTRACT FROM AUTHOR]

Historical vegetation antedates current anthropogenic land use. It can therefore be used to reveal land use/cover changes due to human activities. We collected 197 records from Chinese historical documents, including gazettes, government files, private literature, and travel notes, to reveal vegetation status during the late seventeenth century to early twentieth century across Northeast China. The results indicate that woodland and grassland were the dominant landscapes, whereas swamps accounted for a small area. Woodland was composed of needleleaf deciduous forest, broadleaf deciduous forest, and mixed needleleaf and broadleaf forest. Mixed forest occupied the largest area. This forest type covered most of the Greater Khingan Range, Lesser Khingan Range, and Changbai Mountains. Grassland occupied the Songnen Plain, Liao River Plain, and Inner Mongolia Plateau, whereas swamps covered nearly the entire Sanjiang Plain. In addition, the data revealed that most current cropland was converted from grassland in the Northeast Plain, whereas a small area of cropland was converted from woodland and swamp. [ABSTRACT FROM AUTHOR]

According to the concept of ecoclimatic factor's guarantee rate, this study purposes to quantitatively analyze the interdecadal changes of the four major vegetation transition zones in Northeast China based on the warmth index first developed by Kira and the humidity index put forward by Xu during the period 1961-2007. On this basis, the responses of the interdecadal changes of vegetation transition zones to climate were analyzed. The results indicated that latitudinal vegetation transition zones had been moving laggingly to higher latitude (shifting upwards in altitude) and that longitudinal vegetation transition zones had been shifting slowly toward humid area in the whole sequence, whereas the shifts were fluctuant in stages. The changes of vegetation transition zones of Northeast China expressed in distribution and bandwidth responded to climate change, not only in the whole sequence but also in stages. [ABSTRACT FROM AUTHOR]

Grazing of grasslands changes soil physical and chemical properties as well as vegetation characteristics, such as vegetation cover, species composition and biomass production. In consequence, nutrient allocation and water storage in the top soil are affected. Land use and management changes alter these processes. Knowledge on the impacts of grazing management on nutrient and water fluxes is necessary because of the global importance of grasslands for carbon sequestration. Soil water in semi-arid areas is a limiting factor for matter fluxes and the intrinsic interaction between soil, vegetation and atmosphere. It is therefore desirable to understand the effects of grazing management and stocking rate on the spatial and temporal distribution of soil moisture. In the present study, we address the question how spatio-temporal soil moisture distribution on grazed and ungrazed grassland sites is affected by soil and vegetation properties. The study took place in the Xilin river catchment in Inner Mongolia (PR China). It is a semi-arid steppe environment, which is characterized by still moderate grazing compared to other regions in central Inner Mongolia. However, stocking rates have locally increased and resulted in a degradation of soils and vegetation also in the upper Xilin River basin. We used a multivariate geostatistical approach to reveal spatial dependencies between soil moisture distribution and soil or vegetation parameters. Overall, 7 soil and vegetation parameters (bulk density, sand, silt and clay content, mean weight diameter, mean carbon content of the soil, vegetation cover) and 57 soil moisture data sets were recorded on 100 gridded points on four sites subject to different grazing intensities. Increasing stocking rates accelerated the influence of soil and vegetation parameters on soil moisture. However, the correlation was rather weak, except for a site with high stocking rate where higher correlations were found. Low nugget ratios indicate spatial dependency between soil or plant parameters and soil moisture on a long-term ungrazed site. However, the effect was not found for a second ungrazed site that had been excluded from grazing for a shorter period. Furthermore the most important soil and vegetation parameters for predicting soil moisture distribution varied between different grazing intensities. Therefore, predicting soil moisture by using secondary variables requires a careful selection of the soil or vegetation parameters. [ABSTRACT FROM AUTHOR]

The relationship between vegetation on the Tibetan Plateau (TP) and summer (June-August) rainfall in China is investigated using the normalized difference vegetation index (NDVI) from the Earth Resources Observation System and observed rainfall data from surface 616 stations in China for the period 1982-2001. The leading mode of empirical orthogonal functions analysis for summer rainfall variability in China shows a negative anomaly in the area from the Yangtze River valley to the Yellow River valley (YYR) and most of western China, and positive anomalies in southern China and North China. This mode is significantly correlated with summer NDVI around the southern TP. This finding indicates that vegetation around the southern TP has a positive correlation with summer rainfall in southern China and North China, but a negative correlation with summer rainfall in YYR and western China. We investigate the physical process by which vegetation change affects summer rainfall in China. Increased vegetation around the southern TP is associated with a descending motion anomaly on the TP and the neighboring area to the east, resulting in reduced surface heating and a lower Bowen ratio, accompanied by weaker divergence in the upper troposphere and convergence in the lower troposphere on the TP. In turn, these changes result in the weakening of and a westward shift in the southern Asian High in the upper troposphere and thereby the weakening of and an eastward withdrawal in the western Pacific subtropical high. These features result in weak circulation in the East Asian summer monsoon. Consequently, enhanced summer rainfall occurs in southern China and North China, but reduced rainfall in YYR. [ABSTRACT FROM AUTHOR]

The height profile of sand-dust flux at 0-2.0-m has been well studied. However, there have been very few experimental studies in the 0-50-m layer. In this study, the height profile of sand-dust flux at 0-50-m was observed by using three sandstorm observation towers (50 m in height) in 2006. The towers were located at three sites with different vegetation conditions (desert, edge of an oasis, and oasis) in the Minqin region, a typical desert-oasis area in China. At the same time, the features of the underlying vegetation were investigated. Results indicated that in the 0-50-m layer, sand-dust flux decreased rapidly as height rose at the desert and the edge of oasis sites, whereas it increased slightly as height rose in the oasis site. At the three sites sand-dust fluxes at each height increased with wind velocity, and there was a fairly good exponential relationship among them. In 2006, a total of 19 sandstorms occurred. The annual sand-dust that passed through a 1-m-wide, 50-m-high section was 9,169 kg at the desert site, 5,318 kg at the edge of oasis site, and 2,345 kg at the oasis site. Compared with the desert site, the annual sand flux was lower by 42% at the edge of oasis site and 74% at the oasis site. Vegetation had a significant effect in reducing the sand-dust flux. [ABSTRACT FROM AUTHOR]

Proper assessment and early detection of land degradation and desertification is extremely important in arid and semi-arid ecosystems. Recent research has proposed to use the characteristics of spatial vegetation patterns, such as parameters derived from power-law modeling of vegetation patches, for detecting the early signs of desertification. However, contradictory results have been reported regarding the suitability of those proposed indicators. We used an experiment with multiple grazing intensities as an analog of a desertification gradient and evaluated the performance of two predictors of desertification: percent plant cover and a transition from a patch-area distribution characterized by a power law to another portrayed by a truncated power law, in a desert steppe in Inner Mongolia, China. We found that spatial metrics, such as the largest patch index and coefficient of variation of mean patch area had negative linear relationships with grazing intensity, suggesting that vegetation patches became more fragmented and homogeneous under higher grazing pressure. Using a binning-based method to analyze our dataset, we found that the patch-area relationship deviated from a power-law to a truncated power-law model with increasing grazing pressure, while the truncated power law was a better fit than the power law for all plots when binning was not used. These results suggest that the selection of methodology is crucial in using power-law models to detect changes in vegetation patterns. Plant cover was significantly correlated with stocking rate and all spatial metrics evaluated; however, the relationship between cover and vegetation spatial pattern still deserves a thorough examination, especially in other types of ecosystems, before using cover as a universal early sign of desertification. Our results highlight a strong connection between the vegetation spatial pattern and the desertification associated with heavy grazing and suggest that future studies should incorporate information about vegetation spatial pattern in monitoring desertification processes. [ABSTRACT FROM AUTHOR]

Climate and topography are the two key factors influencing vegetation pattern, distribution, and plant growth. Traditionally, studies on the relationship between vegetation and climate rely largely on field data from limited samples. Now, digital elevation model (DEM) and remote sensing data readily provide huge amounts of spatial data on site-specific conditions like elevation, aspect, and climate, while recent development of geographically weighted regression (GWR) analysis facilitates efficient spatial evaluation of interactions among vegetation and site conditions. Using Haihe Catchment as a case study, GWR is applied in establishing spatial relations among leaf area index (LAI; a critical vegetation index from Moderate Resolution Imaging Spectroradiometer (MODIS)) and interpolated climate variables and site conditions including elevation, aspect, and Topographic Wetness Index (TWI). This study suggests that the GWR solution to spatial effect of climate and site conditions on vegetation is much better than ordinary least squares (OLS). In most of the study area, effects of elevation, aspect change from south to north, and precipitation on LAI are positive, while temperature, TWI, and potential evapotranspiration have a negative influence. Spatially, models perform better in places with large spatial variations in LAI—primarily driven by strong spatial variations in temperature and precipitation. On the contrary, the effect of topographic and climatic factors on vegetation is weak in regions with small spatial variations in LAI. This study shows that overall water availability is a determining factor for spatial variations in vegetation. [ABSTRACT FROM AUTHOR]

Remote sensing of local environmental conditions is not accessible if substrates are covered with vegetation. This study explored the relationship between vegetation spectra and karst eco-geo-environmental conditions. Hyperspectral remote sensing techniques showed that there were significant differences between spectral features of vegetation mainly distributed in karst and non-karst regions, and combination of 1,300- to 2,500-nm reflectance and 400- to 680-nm first-derivative spectra could delineate karst and non-karst vegetation groups. Canonical correspondence analysis (CCA) successfully assessed to what extent the variation of vegetation spectral features can be explained by associated eco-geo-environmental variables, and it was found that soil moisture and calcium carbonate contents had the most significant effects on vegetation spectral features in karst region. Our study indicates that vegetation spectra is tightly linked to eco-geo-environmental conditions and CCA is an effective means of studying the relationship between vegetation spectral features and eco-geo-environmental variables. Employing a combination of spectral and spatial analysis, it is anticipated that hyperspectral imagery can be used in interpreting or mapping eco-geo-environmental conditions covered with vegetation in karst region. [ABSTRACT FROM AUTHOR]

Changes in climate as projected by state-of-the-art climate models are likely to result in novel combinations of climate and topo-edaphic factors that will have substantial impacts on the distribution and persistence of natural vegetation and animal species. We have used multivariate techniques to quantify some of these changes; the method employed was the Multivariate Spatio-Temporal Clustering (MSTC) algorithm. We used the MSTC to quantitatively define ecoregions for the People’s Republic of China for historical and projected future climates. Using the Köppen–Trewartha classification system we were able to quantify some of the temperature and precipitation relationships of the ecoregions. We then tested the hypothesis that impacts to environments will be lower for ecoregions that retain their approximate geographic locations. Our results showed that climate in 2050, as projected from anthropogenic forcings using the Hadley Centre HadCM3 general circulation model, were sufficient to create novel environmental conditions even where ecoregions remained spatially stable; cluster number was found to be of paramount importance in detecting novelty. Continental-scale analyses are generally able to locate potentially static ecoregions but they may be insufficient to define the position of those reserves at a grid cell-by-grid cell basis. [ABSTRACT FROM AUTHOR]

The Conversion of Cropland to Forest and Grassland Program (CCFG), which was initiated by the Chinese government in 1999, is a cropland retirement program with integrated objectives for ecological preservation and local development. The purpose of this article was to study the influencing factors of attitude and economic strategies in rural households toward the CCFG. Rural households’ knowledge, attitude and economic strategies toward the CCFG were investigated through a questionnaire survey in Qira, China. Influencing factors of attitude and strategies of households were analyzed using a logit model technique. The analysis indicated that household’s income level, environmental knowledge of the program, and program implementation were significant influencing factors in a household’s attitude toward the CCFG, while major influencing factors of household strategies were their regional background and availability of income generation sources. Meaningful association was not found between attitude and strategy choices. Rich households had more strategy choices, while poor households were usually confined to low input strategies with uncertain income. To sustain their livelihood, the poor need extra assistances in marketing, loan granting, employment training, information, and technical services. [ABSTRACT FROM AUTHOR]

Leaf area index (LAI) is a key variable functionally related to plant biomass production. Accurate estimation of LAI is important for monitoring vegetation dynamics, and LAI information is essentially required for the prediction of microclimate and various biophysical processes within and below canopy. The traditional, direct and destructive method of measuring LAI is time-consuming. Modern gap fraction technique can assess LAI fast and easily, however its application is problematic with vegetations of low stature. Alternatively, NDVI (Normalized Difference Vegetation Index) as a widely used spectral reflectance index has been shown to be a good estimator of LAI and is used to estimate LAI indirectly. In situ measurements of NDVI and LAI at three sites in semi-arid grassland in Inner Mongolia, China were carried out during the growing season in 2005 and 2006. Based on these sites, a general linear and a general exponential relationship (LAI = −0.0897 + 1.424 * NDVI, R = 0.79; LAI = 0.128 * exp(NDVI/0.311), R = 0.77) were developed, which can be used for various grazing intensity grasslands and also for higher vegetation cover area (e.g. wetland) in the region. These equations for estimating LAI are suitable for the natural range of vegetation in this area during the growing season under both normal and dry weather conditions. By simply applying NDVI measurements and these relationships, the vegetation status and grass yield in the area will be rapidly and nondestructively estimated, which is helpful for livestock management and sustainable land use. [ABSTRACT FROM AUTHOR]

Empirical Orthogonal Function (EOF) analysis and the related Principal Components (PC) analysis are used to extract valuable vegetation cover derived information from the National Oceanic and Atmospheric Administration (NOAA-AVHRR)'s Leaf Area Index (LAI) satellite images. Results suggest that from 1982 to 2000 global climate change has contributed to an increase in vegetation cover in the Qinghai-Tibet Plateau. The correlation between rainfall and LAI EOF PC1 and PC2 indicates that rainfall is the major climatic factor influencing interannual variations of average vegetation cover throughout the entire Plateau. However, annual mean vegetation cover trends in the Qinghai-Tibet Plateau are mainly out of phase with air temperature increasing, which is primarily responsible for nonsynchronous changes of vegetation cover. In the southern ridge of the Qinghai-Tibet Plateau, recent warming trends contribute to humid weather and favorable conditions for vegetation growth. By contrast, higher temperatures have led to arid conditions and insufficient rainfall in the northern part of the Plateau, leading to drought and other climatic conditions which are not conducive to increased vegetation cover. [ABSTRACT FROM AUTHOR]