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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. 

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.

Abstract Despite the looming land scarcity for agriculture, cropland abandonment is widespread globally. Abandoned cropland can be reused to support food security and climate change mitigation. Here, we investigate the potentials and trade-offs of using global abandoned cropland for recultivation and restoring forests by natural regrowth, with spatially-explicit modelling and scenario analysis. We identify 101 Mha of abandoned cropland between 1992 and 2020, with a capability of concurrently delivering 29 to 363 Peta-calories yr− 1 of food production potential and 290 to 1,066 MtCO2 yr− 1 of net climate change mitigation potential, depending on land-use suitability and land allocation strategies. We also show that applying spatial prioritization is key to maximizing the achievable potentials of abandoned cropland and demonstrate other possible approaches to further increase these potentials. Our findings offer timely insights into the potentials of abandoned cropland and can inform sustainable land management to buttress food security and climate goals.

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.

AbstractPhosphorus (P) accumulators used for phytoremediation vary in their potential to acquire P from different high P regimes. Growth and P accumulation in Polygonum hydropiper were both dependent on an increasing level of IHP (1–8 mM P) and on a prolonged growth period (3-9 weeks) and those of the mining ecotype (ME) were higher than the non-mining ecotype (NME). Biomass increments in root, stem and leaf of both ecotypes were significantly greater in IHP relative to other organic P (Po) sources (G1P, AMP, ATP), but lower than those in inorganic P (Pi) treatment (KH2PO4). P accumulation in the ME exceeded the NME from different P regimes. The ME demonstrated higher root activity compared to the NME grown in various P sources. Acid phosphatase (Apase) and phytase activities in root extracts of both ecotypes grown in IHP were comparable to that in Pi, or even higher in IHP. Higher secreted Apase and phytase activities were detected in the ME treated with different P sources relative to the NME. Therefore, the ME demonstrates higher P-uptake efficiency and it is a potential material for phytoextraction from P contaminated areas, irrespective of Pi or Po contamination.

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).

The impacts of increasing natural climate disasters are threatening food security in the Asia-Pacific region. Rice is Asia’s most important staple food. Climate variability and change directly impact rice production, through changes in rainfall, temperature and CO2 concentrations. The key for sustainable rice crop is water management. Adaptation can occur through shifts of cropping to higher latitudes and can profit from river systems (via irrigation) so far not considered. New opportunities arise to produce more than one crop per year in cooler areas. Asian wheat production in 2005 represents about 43 % of the global total. Changes in agronomic practices, such as earlier plant dates and cultivar substitution will be required. Fisheries play a crucial role in providing food security with the contribution of fish to dietary animal protein being very high in the region – up to 90 % in small island developing states (SIDS). With the warming of the Pacific and Indian Oceans and increased acidification, marine ecosystems are presently under stress. Despite these trends, maintaining or enhancing food production from the sea is critical. However, future sustainability must be maintained whilst also securing biodiversity conservation. Improved fisheries management to address the existing non-climate threats remains paramount in the Indian and Pacific Oceans with sustainable management regimes being established. Climate-related impacts are expected to increase in magnitude over the coming decades, thus preliminary adaptation to climate change is valuable.