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Widespread shrub encroachment is profoundly impacting the structures and functions of global drylands, and precipitation change is assumed to be one of the most critical factors affecting this phenomenon. However, there is little evidence to show how precipitation changes will affect the process. In this study, we conducted a 6-year precipitation manipulation experiment (-30%, ambient, +30%, and +50%) to investigate the effects of precipitation changes on the growth of shrubs and herbaceous plants in a shrub-encroached grassland in Inner Mongolia. We found that the increasing precipitation significantly increased the mean height, coverage, and aboveground biomass of herbaceous species, while the growth of shrub species did not exhibit a significant response to precipitation changes. With increasing precipitation, the relative coverage of shrubs decreased, while that of herbs increased. The native dominant herbaceous plant (Leymus chinensis) with more sensitive maximum photosynthetic rate to the precipitation change, showed higher photosynthetic nitrogen use efficiency and water use efficiency than those of the encroached shrub species (Caragana microphylla) at high soil moisture contents, reflecting that the ecophysiological characteristics of L. chinensis might provide it a competitive advantage under increased precipitation. Our findings suggest that increasing precipitation may slow down shrub encroachment by facilitating herbaceous growth in Mongolian grasslands, and consequently affect the forage value and carbon budget in these ecosystems. 

In order to identify a potential surrogate of planktonic ciliate communities for marine bioassessments and evaluating biological conservations, the different taxonomic/numerical resolutions and taxa as surrogates were studied in Jiaozhou Bay, northern China during a 1-year cycle (June 2007-May 2008).Samples were collected biweekly from a depth of 1 m at each of five sites. A range of physicochemical parameters were also measured in order to determine water quality.The genus- and family-level resolutions maintained sufficient information to evaluate the ecological patterns of the ciliate communities in response to environmental status. The non-loricate oligotrichous ciliate assemblages in both abundance and occurrence may be used as a surrogate of planktonic ciliate communities. Heavy data transformations were an optimal strategy for the species level of planktonic ciliates, while mild data transformations were for the higher. The ordination patterns based on species biomass, occurrence, and biomass/abundance ratio matrices were significantly consistent with that of species abundance data.The results suggest that the use of simplifications at both taxonomic and numerical resolutions are time-efficient and would allow improving sampling strategies of large spatial/temporal scale monitoring programs and biological conservation researches in the marine ecosystem with a relative paucity of scientists.

Lower Mekong Basin (LMB) experiences a recurrent drought phenomenon. However, few studies have focused on drought monitoring in this region due to lack of ground observations. The newly released Climate Hazards Group Infrared Precipitation with Station data (CHIRPS) with a long-term record and high resolution has a great potential for drought monitoring. Based on the assessment of CHIRPS for capturing precipitation and monitoring drought, this study aims to evaluate the drought condition in LMB by using satellite-based CHIRPS from January 1981 to July 2016. The Standardized Precipitation Index (SPI) at various time scales (1–12-month) is computed to identify and describe drought events. Results suggest that CHIRPS can properly capture the drought characteristics at various time scales with the best performance at three-month time scale. Based on high-resolution long-term CHIRPS, it is found that LMB experienced four severe droughts during the last three decades with the longest one in 1991–1994 for 38 months and the driest one in 2015–2016 with drought affected area up to 75.6%. Droughts tend to occur over the north and south part of LMB with higher frequency, and Mekong Delta seems to experience more long-term and extreme drought events. Severe droughts have significant impacts on vegetation condition.

Forest soil acidification caused by acid deposition is a serious threat to the forest ecosystem. To investigate the liming effects of biomass ash (BA) and alkaline slag (AS) on the acidic topsoil and subsoil, a three-year field experiment under artificial Masson pine was conducted at Langxi, Anhui province in Southern China. The surface application of BA and AS significantly increased the soil pH, and thus decreased exchangeable acidity and active Al in the topsoil. Soil exchangeable Ca2+ and Mg2+ in topsoil were significantly increased by the surface application of BA and AS, while an increase in soil exchangeable K+ was only observed in BA treatments. The soil acidity and active Al in subsoil were decreased by the surface application of AS. Compared with the control, soluble monomeric and exchangeable Al in the subsoil was decreased by 38.0% and 29.4% after 3 years of AS surface application. There was a minimal effect on soluble monomeric and exchangeable Al after the application of BA. The soil exchangeable Ca2+ and Mg2+ in the subsoil increased respectively by 54% and 141% after surface application of 10 t ha-1 AS. The decrease of soil active Al and increase of base cations in subsoil were mainly attributed to the high migration capacity of base cations in AS. In conclusion, the effect of surface application of AS was superior to BA in ameliorating soil acidity and alleviating soil Al toxicity in the subsoil of this Ultisol.

This study focused on the effects of plant compositions on removal rates of pollutants in microcosms through investigating rhizosphere microbial populations, photosynthetic efficiency and growth characteristics. Mixed-culture groups improved the removal efficiency of TN and TP significantly but exhibited lower COD removal rates. Total plant biomasses were improved as the species richness increased, but the N/P content in the plants was mainly affected by the type of species. The mixed-culture groups showed lower photosynthesis rates and oxygen supply generated from roots under high irradiation. Microbial communities of the cultured groups in the rhizosphere exhibited significant differences. According to principal component analysis (PCA), the fungi were the typical microbes of SPA, SPAB, and SPABC, resulted in improvement in nutrient accumulation. These results demonstrated that a mixed culture strategy can represent the overyielding of biomass, promote the photo-protection mechanism, and will further increase the removal rates of pollutants in a constructed wetland.

AbstractAcross southern China, Moso bamboo has been encroaching on most neighboring secondary broad-leaved forests and/or coniferous plantations, leading to the land cover changes that alter abiotic and biotic conditions. Little is known about how this conversion alters soil carbon (C) and nitrogen (N). We selected three sites, each with three plots arrayed along the bamboo encroachment pathway: moso bamboo forest (BF); transition zone, mixed forest plots (MF); and broad-leaved forest (BLF), and examined how bamboo encroachment affects soil organic C (SOC), soil total N, microbial biomass C (MBC), microbial biomass N (MBN), water-soluble organic C (WSOC), and water-soluble organic N (WSON) in three forests. Over nine years, moso bamboo encroachment leads to a decrease in SOC and total soil N, an increase in MBC and WSOC, and a decrease in MBN and WSON. Changes in soil C and N occurred mainly in the topsoil. We conclude that moso bamboo encroachment on broadleaved forest not only substantially altered soil C and N pools, but also changed the distribution pattern of C and N in the studied forest soils. Continued bamboo encroachment into evergreen broadleaved forests seems likely to lead to net CO2 emissions to the atmosphere as ecosystem C stocks decline.

This dataset provides grided species phenology (SP) maps of 24 woody plants and ground phenology (GP) maps of forests over China (18°N-54°N，72′°E-136°E) from 1951 to 2020, with a spatial resolution of 0.1° and a temporal resolution of 1 day. Three phenophases, namely the first leaf date (FLD), first flower date (FFD), and 100% leaf coloring date (LCD), were included for each species. Data Quality: The SP maps of 24 species are largely consistent with the in-situ observations in China, with an average error of 6.4, 7.5 and 10.8 days for FLD, FFD and LCD, respectively. The GP maps of forests have good consistency with the existing LSP products in China, particularly in DF areas, where the correlation coefficients between GP and LSP in FLD and LCD were 0.91 and 0.84, respectively, and the differences were 8.8 days and 15.1 days, respectively. Method: Based on the in-situ phenology observations from the Chinese Phenology Observation Network (CPON) in the past 70 years, this dataset employed three spring phenology models (Unichill, Unified and Temporal-Spatial Coupling) and two autumn phenology models (Multiple Regression, Temperature-Photoperiod) to simulate and upscale the phenology data on the national scale, and generate the SP maps of woody plants in China. Four aggregation methods (weighted average (mean), weighted percentile (pct50, pct20\80, pct10\90)) were used to generate the GP maps of forests in China based on the SP maps. The weight of each species was determined by the species distribution probability. Dataset composition: The dataset contains the yearly SP maps of 24 woody plants (China_SP.zip) and GP maps of forests(China_GP.zip) over China from 1951 to 2020, including spring FLD, FFD and autumn LCD. Each map is stored in a GeoTIFF formatted 16-bit signed integer file containing a raster with two dimensions (641 row × 361 column). Data files are named according to "China + phenophase (XXD) + species/method + year (YYYY)". For example, "China_FLD_Acer_pictum_2020.tif" is the SP map of Acer pictum’s FLD in 2020, and “China_FLD_mean_2020.tif” is the GP map of weighted averaged FLD in 2020. The unit of phenology data is Julian day of year (DOY), which represents the actual number of days from the date of phenology occurrence to January 1 of the current year. The valid value is 1-366, and the invalid filling value is -1. The spatial reference system of the data is EPSG:4326 (WGS84). This dataset provides grided species phenology (SP) maps of 24 woody plants and ground phenology (GP) maps of forests over China (18°N-54°N，72′°E-136°E) from 1951 to 2020, with a spatial resolution of 0.1° and a temporal resolution of 1 day. Three phenophases, namely the first leaf date (FLD), first flower date (FFD), and 100% leaf coloring date (LCD), were included for each species. Data Quality: The SP maps of 24 species are largely consistent with the in-situ observations in China, with an average error of 6.4, 7.5 and 10.8 days for FLD, FFD and LCD, respectively. The GP maps of forests have good consistency with the existing LSP products in China, particularly in DF areas, where the correlation coefficients between GP and LSP in FLD and LCD were 0.91 and 0.84, respectively, and the differences were 8.8 days and 15.1 days, respectively. Method: Based on the in-situ phenology observations from the Chinese Phenology Observation Network (CPON) in the past 70 years, this dataset employed three spring phenology models (Unichill, Unified and Temporal-Spatial Coupling) and two autumn phenology models (Multiple Regression, Temperature-Photoperiod) to simulate and upscale the phenology data on the national scale, and generate the SP maps of woody plants in China. Four aggregation methods (weighted average (mean), weighted percentile (pct50, pct20\80, pct10\90)) were used to generate the GP maps of forests in China based on the SP maps. The weight of each species was determined by the species distribution probability. Dataset composition: The dataset contains the yearly SP maps of 24 woody plants (China_SP.zip) and GP maps of forests(China_GP.zip) over China from 1951 to 2020, including spring FLD, FFD and autumn LCD. Each map is stored in a GeoTIFF formatted 16-bit signed integer file containing a raster with two dimensions (641 row × 361 column). Data files are named according to "China + phenophase (XXD) + species/method + year (YYYY)". For example, "China_FLD_Acer_pictum_2020.tif" is the SP map of Acer pictum’s FLD in 2020, and “China_FLD_mean_2020.tif” is the GP map of weighted averaged FLD in 2020. The unit of phenology data is Julian day of year (DOY), which represents the actual number of days from the date of phenology occurrence to January 1 of the current year. The valid value is 1-366, and the invalid filling value is -1. The spatial reference system of the data is EPSG:4326 (WGS84).

This dataset reports results on seedling growth and survival for two hyphal exclusion experiments in a subtropical forest. The data include survival status, height, total biomass and the biomass of component plant parts, percentage root colonisation by mycorrhizas, for tree seedlings of ten common species including five ectomycorrhizal (ECM) and five arbuscular mycorrhizal (AM) species, which were transplanted in the in-growth cores with windows covering different sizes of nylon meshes (35 vs. 0.5 µm). The dataset provides raw data on growth and survival metrics for each seedling, plus identifying codes for the dominant sites where the experiments were conducted, as well as experimental block, mesh treatment, botanical names for the tree species, and mycorrhizal type. The data were entered into Excel spreadsheets and exported as comma separated value files (csv). Study area - the Heishiding Nature Reserve (111°53’E, 23°27’N, 150-927 m a.s.l.) in Guangdong Province of south China. Mesh-walled cores were assembled from 16 cm diameter × 30 cm deep PVC piping, perforated with six 8-cm-diameter windows which were regularly distributed along the side with three of them at the depth of 4-12 cm and the other three at 16-24 cm. The cores were lined with 35 µm or 0.5 µm nylon mesh (Plastok Associates Ltd, Birkenhead, UK) to cover the bottom and the windows, which was attached using transparent superglue (Pattex(R), Henkel Adhesives Ltd., Shantou, China). Nylon mesh with a pore size of 35 µm excludes roots of neighboring plants, but allows mycorrhizal hyphae access to the transplanted seedlings; while cores with a 0.5 µm mesh exclude both fine roots and hyphae, with only free-living soil microorganisms passing through. We then covered the sides and the bottoms of all cores with 2 mm nylon mesh, to prevent soil fauna damaging the smaller size meshes.