Three-North Region Research Articles

Changes in terrestrial water storage in the Three-North region of China over 2003–2021: Assessing the roles of climate and vegetation restoration

Large-scale vegetation restoration has markedly enhanced ecosystem services in the Three-North (TN) region, concurrently exacerbating the pre-existing water resource crisis stemming from climate change in this arid domain. However, the specific contributions of climate and vegetation changes to the evolution of water resources in the TN region have yet to be elucidated. This study leverages data from the Gravity Recovery and Climate Experiment (GRACE) and its Follow-on mission (GRACE-FO), specifically the terrestrial water storage anomaly (TWSA) from 2003 to 2021. We identify two TWSA rising (TWSA_rⅠ and TWSA_rⅡ) and two declining (TWSA_dⅠ and TWSA_dⅡ) hotspots in the TN region. By exploring the relative importance of climate drivers and vegetation dynamics in influencing the temporal dynamics of TWSA, we found that vegetation restoration assumes a more pivotal role than climate factors in 45.2% of the total area within the identified hotspots, predominantly evident in TWSA declining hotspots. The heightened TWSA in TWSA_rⅠ and TWSA_rⅡ primarily stems from precipitation recharge, with precipitation-dominated areas constituting 19.3% of the area within the identified hotspots. Potential evapotranspiration dominates TWSA changes in only 4.6% of the region within the identified hotspots, primarily scattered in TWSA_dⅠ and TWSA_dⅡ. Furthermore, a comparative assessment of soil moisture and groundwater responses to environmental factors indicates that water storage at shallower layers is more responsive to climate factors, while the impacts of vegetation changes on TWSA are more discernibly reflected in water storage at deeper layers. These findings furnish scientific guidance for future ecological restoration planning and sustainable water resources management.

Conservation Effectiveness Assessment of the Three Northern Protection Forest Project Area

The Three-North Shelterbelt Project is the largest ecological engineering initiative in China to date, distinguished by its immense scale, extended construction period, and widespread benefits for the population. The gross ecosystem product (GEP) serves as a crucial indicator for assessing ecological benefits. This study focuses on the Three Northern Protection Forest Project Area, utilizing GEP calculations for the years 2000 to 2020. This study evaluates variations in the production values of different ecosystem services to reflect the ecological conservation benefits of the restoration project. Additionally, it analyzes the spatiotemporal evolution and trends of the GEP calculations, offering data references and decision support for the enduring efficacy of ecological restoration projects. The findings are as follows. (i) Between 2000 and 2020, the GEP of the Three-North region exhibited significant growth with continuous enhancement of various ecosystem service functions; the most substantial rate of change was observed in the water conservation function, followed by carbon sequestration and oxygen release, soil retention, windbreak and sand fixation, flood regulation, and environmental purification functions. (ii) The per-unit area value of different ecosystem types generally increased; the forest ecosystem displayed the largest growth rate at 61.18%, followed by shrubland ecosystems at 49.84%. (iii) The spatial distribution of ecosystem service in the Three-North region displayed a clustering trend alongside notable spatial heterogeneity. High-high clustering zones were identified in areas such as the Tianshan Mountains, Altai Mountains, Qilian Mountains, and Greater and Lesser Khingan Mountains. Conversely, low-low clustering areas were scattered, forming patchy distributions in regions like the Tarim Basin, northern Qinghai-Tibet Plateau, and the Hexi Corridor. This study, by analyzing the gross ecosystem product of the Three-North Shelterbelt Project region, unveils the spatial distribution characteristics, trends, and variations in ecosystem service values over the past two decades. It provides data support and decision guidance for the long-term efficacy of future ecological conservation and restoration projects. This study incorporates the GEP accounting method into the assessment of the effectiveness of major conservation projects. Compared to the traditional methods of effectiveness assessment, this represents a significant exploration and innovation.

Spatial-temporal changes and driving factors of eco-environmental quality in the Three-North region of China

Spatial-temporal changes and driving factors of eco-environmental quality in the Three-North region of China

Response of Vegetation Dynamics in the Three-North Region of China to Climate and Human Activities from 1982 to 2018

To tackle ecological problems, many ecological restoration projects have been implemented in northern China. Identifying the drivers of vegetation change is critical for continued ecological engineering. In this study, three typical ecological reserves in the Three-North Shelter Forest Program Region (TNSFR) were selected to identify their vegetation development characteristics and driving mechanisms using the normalized difference vegetation index (NDVI), climate factors, and land use data. The results show that (1) NDVIs increased in the range of human activities of all of the three ecological reserves, indicating an obvious effect of the vegetation restoration projects. (2) In the planting period, vegetation restoration was mainly correlated with human activities. After entering the tending period, the impact of climate changes on vegetation dynamics was enhanced. (3) Temperature and precipitation provided approximate driving effects on vegetation dynamics in Region I, while vegetation dynamics in Regions II and III were more strongly correlated with precipitation. (4) The proportion of areas with ecological measures exceeded 50% in all three regions. In short, ecological projects in the three ecological reserves dominated the quantity of vegetation restoration, while climate changes influenced the quality of vegetation restoration.

Detecting Spatiotemporal Differences in Cropland Abandonment and Reforestation Across the Three-North Region of China Based on Landsat Time Series

The Three-North region of China is an important ecological protection area. While the depopulation of rural areas and policy intervention have allowed cropland abandonment and reforestation (CAR), the spatial distribution and temporal differences underlying this landscape pattern have not been analyzed. CAR results in the gradual disappearance of the soil signal representing tilled or harvested crops, followed by a gradual increase in the interannual vegetation signal. This long-term gradual greening can be exploited to map the spatiotemporal distribution of CAR. In this study, Landsat-based detection of trends in disturbance and recovery (LandTrendr) was applied to the 1990–2020 Landsat-derived normalized difference vegetation index (NDVI) time series. The data were combined with a differential analysis of the phenological characteristics of the surveyed area to detect land surface greening trends. The relationship with actual information on CAR was then determined. The results showed widespread long-term greening in the Three-North region, covering up to 80% of the region) during the annual growth (May–June) and harvest (September–October) periods. Together, these two periods indicated 7.5% overall greening. The highest greening intensity was in areas where cropland undergone conversion to forest, which strongly suggested CAR as the succession type. The average accuracy of CAR mapping was ~80% (mapping accuracy of a greening intensity > 0.4 was as high as 87%). This study demonstrates the utility of our method in studies of driving factors of CAR and ecological benefits of secondary forest restoration.

Effects of Ecological Programs and Other Factors on Soil Wind Erosion between 1981–2020

Wind erosion is one of the most widespread and severe natural hazards in arid, semiarid, and semihumid regions worldwide. The Three-North region (TNR) (Northeast China, North China, and Northwest China) of China includes 90% of the wind erosion area in China. In response to the harsh environmental conditions in the TNR, China initiated a series of ecological programs, including the Three-North Afforestation Program and Grain for Green. However, little is known about the effect of these ecological programs on wind erosion. Therefore, within our study, we estimated the spatiotemporal variations in wind erosion in the TNR between 1981–2020 with a revised wind erosion model and analyzed its driving mechanism. Then, the ecological programs’ effects on wind erosion changes was identified. The results showed the following. (1) From 1981 to 2020, wind erosion showed a clear downward trend of 99.02 t km−2 a−1, with a slope. On average, the areas of mild, moderate, severe, more severe, and very severe wind erosion accounted for 28.76%, 7.17%, 3.92%, 3.72%, and 13.29% of the total in the TNR, respectively. (2) Wind erosion variation was inconsistent in different parts of the TNR. The wind erosion expressed a long-term decreasing trend in Northeast China and the Loess Plateau, a nonsignificant change in North Central China, and an increasing trend in Northwest China. (3) On average, ecological programs were very limited in reducing erosion at the regional scale, with a contribution of approximately 5.93% in the TNR because of the relatively small scope of ecological programs’ implementation. Climate change played a key role in adjusting wind erosion; wind speed, temperature, and precipitation affected 57.58% of the TNR. Human interference (proportion of cropland and grassland areas in a 1 km ×1 km grid) affected 8.78% of the TNR. Thus, the persistent complement of ecological programs, reasonable human activities, and timely observation is a method to alleviate wind erosion in the TNR.

Four decades of hydrological response to vegetation dynamics and anthropogenic factors in the Three-North Region of China and Mongolia

Afforestation has been initiated in Northeast Asia to improve ecological status. The responses of the regional hydrological cycle to vegetation restoration remain insufficiently explored. This study uses a variety of satellite-derived vegetation variables and hydrological cycle components to scan the eco-hydrological regimes in the Three-North Region of China and Mongolia during the past four decades. We observe that vegetation productivity increases mainly in North China (NC), Northeast China (NEC), Northwest China (NWC), and the north of Inner Mongolia and Mongolia. Precipitation and runoff show a decreasing trend (−0.4 mm/year and − 0.6 mm/year, respectively), yet they are less correlated to the normalized difference vegetation index and leaf area index. Along with increasing vegetation productivity, evapotranspiration increases (0.05 mm/year) obviously in NC and NEC, while root soil moisture (−0.001 m3/m3/year) and terrestrial water storage (−2.0 mm/year) decrease in NC and parts of NEC and NWC. The correlation coefficient between evapotranspiration and vegetation variables is up to 0.73. Collectively, results imply one potential adverse response of terrestrial water fluxes to increasing vegetation. Independent ecological and hydrological datasets further corroborate our work. Climatic factors (i.e., downward shortwave radiation and air temperature) and human activities (i.e., aerosol optical depth, carbon dioxide, and water withdrawal) substantially affect regional hydrological cycles. Considering the increasing vegetation productivity in the Three-North Region of China and Mongolia is likely to continue in the 21st century based on the Sixth Coupled Model Intercomparison Project (CMIP6) simulations, the terrestrial water fluxes may undergo deficit pressure. Overall, this study comprehensively investigates the vegetation and hydrology interplays, and provides a reference for protecting and improving ecological-hydrological conditions in Northeast Asia.

The trend shift caused by ecological restoration accelerates the vegetation greening of China’s drylands since the 1980s

Satellite observations since the early 1980s have revealed a trend of ‘Earth greening’ across global terrestrial ecosystems. Dryland vegetation is more sensitive to climate change and human activities. China’s drylands are among the largest in extent worldwide, and large-scale ecological restoration of these areas has been implemented since the late 1970s, which has resulted in more complicated but still poorly quantified vegetation dynamics. To figure out the vegetation dynamics and associated driving forces, we provide an assessment of the vegetation dynamics from 1982 to 2015 using the CO2 fertilization effect function, principal component regression, Residual Trend analysis, and Breaks For Additive Seasonal and Trend methods based on the ERA5 climate factors and GIMMS 3.1 normalized difference vegetation index datasets. This study shows that anthropogenic impacts and CO2 fertilization have jointly led to vegetation greening in China’s drylands since the 1980s, and ecological restoration has accelerated this greening since the 2000s. The results show that the vegetation greening in China’s drylands (41.51% of the study area, +0.60 × 10−3 yr−1) is mainly driven by CO2 fertilization (+0.55 × 10−3 yr−1) and anthropogenic activities (+0.12 × 10−3 yr−1). The anthropogenic effects are especially higher on the Loess Plateau (+1.01 × 10−3 yr−1) and the Three-North region (+0.23 × 10−3 yr−1). The vegetation dynamics shifts in 6.73% (31.64 Mha) of China’s drylands were directly attributed to anthropogenic impacts around the 2000s. When the anthropogenic effect was intensified, the vegetation dynamics shifted from no change to greening and vice versa, which significantly intensified the vegetation greening since the 1980s. These results capture the processes of ecological programs and provide an assessment of the effects of ecological restoration. This work provides a credible attribution of the vegetation greenness dynamics and trend shifts in China’s drylands, thus facilitating a better understanding of regional environmental change and management.

Suggestions for Revegetation over the Next 30 Years Based on Precipitation in the Three North Region of China

Afforestation in the Three North Region (TNR) of China has received wide concern due to the low survival rate and threats to water security associated with the lack of available precipitation for vegetation. It is crucial to provide a spatial layout for revegetation according to the available precipitation to achieve the vegetation cover target. This study investigated the spatial pattern of precipitation, determined the suitable vegetation distribution based on the ecological water requirements and precipitation, and proposed an optimized revegetation scheme by comparing the actual and suitable vegetation patterns. The results indicated that the actual vegetation that matched the pixel-level precipitation accounted for 67.24% of the total vegetation area in the TNR. However, 18.50% of the actual forest, 21.82% of the actual shrublands, and 19.95% of the actual grasslands were overloaded with respect to precipitation. The total suitable vegetation area was reduced slightly compared to the actual vegetation area. There is still some potential for the revegetation of forest and shrublands, mainly those in the eastern and south-eastern parts of the TNR. The optimized revegetation area in the TNR was 3.04 × 106 km2, including a maintenance management type of 2.19 × 106 km2, an upgrade type of 0.49 × 106 km2, and a degradation type of 0.37 × 106 km2. Maintenance management (natural restoration) and transformation to vegetation types with lower ecological water requirements were recognized as important revegetation practices in the TNR. This study provides guidelines to adjust the Three North Shelterbelt Project policies based on precipitation data to reduce the negative impact of revegetation on the hydrological cycle.

Ecosystem Water Use Efficiency in the Three-North Region of China Based on Long-Term Satellite Data

Water use efficiency (WUE), given by the ratio between organic matter production and water consumption, could be considered as a very important ecological indicator for assessing vegetation system growth conditions by combining organic matter production and water consumption. It is especially important for regional vegetation sustainable management by creating enough organic matter with restricted water supply. Furthermore, proper analysis of WUE is vital for the evaluation and future plans of ecological restoration projects in ecologically fragile regions such as the Three-North region of China. In this study, ecosystem WUE across the Three-North region of China from 2001 to 2017 was obtained, and the variation trends and major influencing factors were also analyzed. The results demonstrated that (1) the average WUE across the Three-North region of China is 0.7376 g∙C∙m−2∙mm−1 with an annual increase of 0.002 g∙C∙m−2∙mm−1∙y−1; (2) the spatiotemporal variation trends of WUE are similar to those of gross primary production (GPP); and (3) in the southeastern parts of the Three-North region, the vegetation conditions are better with sustainable improvements, while in Xinjiang Province, the sustainable degradation areas are widely spread. The results of this research reveal large spatial heterogeneity of WUE, with high WUE mainly in the southeastern region with sufficient precipitation and afforestation programs. For those areas far away from this region, WUE is not satisfactory, suggesting that, for a sustainable vegetation growth, it is important to consider the water supply to maintain suitable vegetation cover. Furthermore, the results of this research are important for future ecological restoration and sustainable management of environment.

Mapping 30 m Fractional Forest Cover over China’s Three-North Region from Landsat-8 Data Using Ensemble Machine Learning Methods

The accurate monitoring of forest cover and its changes are essential for environmental change research, but current satellite products for forest coverage carry many uncertainties. This study used 30-m Landsat-8 data, and aggregated 1-m GaoFen-2 (GF-2) satellite images to construct the training samples and used multiple machine learning algorithms (MLAs) to estimate the fractional forest cover (FFC) in China’s Three North Region (TNR). In this study, multiple MLAs were merged to construct stacked generalization (SG) models based on the idea of SG, and the performances of the MLAs in the FFC estimation were evaluated. The results of the 10-fold cross-validation showed that all non-linear algorithms had a good performance, with an R2 value of greater than 0.8 and a root-mean square error (RMSE) of less than 0.05. In the bagging ensemble, the random forest (RF) (R2 = 0.993, RMSE = 0.020) model performed the best and in the boosting ensemble, the light gradient boosted machine (LGBM) (R2 = 0.992, RMSE = 0.022) performed the best. Although the evaluation index of the RF is slightly better than that of the LGBM, the independent validation results show that the two models have similar performances. The model evaluation results of the independent datasets showed that, in the SG model, the performance of the SG(LGBM) (R2 = 0.991, RMSE = 0.034) was better than that of the single or non-ensemble model. Comparing the FFC estimates of our model with those of existing datasets showed that our model exhibited more forest spatial distribution details and higher accuracy in complex landscapes. Overall, in this study, the method of using high-resolution remote sensing (RS) images to extract samples for FFC estimation is feasible. Our results demonstrate the potential of the ensemble MLAs to map the FFC. The research results also show that among many MALs, the RF algorithm is the most suitable algorithm for estimating FFC, which provides a reference for future research.

China’s Key Forestry Ecological Development Programs: Implementation, Environmental Impact and Challenges

Forest ecosystems are in serious trouble globally, largely due to the over-exploitation. To alleviate environmental problems caused by deforestation, China has undertaken a series of key forestry ecological development programs, including the Natural Forest Protection Program (NFPP), the Conversion of Cropland into Forests Program (CCFP), the Desertification Combating Program around Beijing and Tianjing (DCBT), the Key Shelterbelt Development Programs in the Three-North Region and in the Middle and Lower Reaches of the Yangtze River (KSDP) and the Nature Reserve Development Program in Forestry Sector (WCNR). This article aims to make a documentation of the specific contents (duration, major aims, geographic coverage and investment), and environmental impacts of these programs from peer-reviewed literature, official reports and journals. Environmental impact is measured with land area afforested (except the WCNR) and the consequent changes in ecosystem function. Overall, with the huge investment and long-term efforts, these programs have made tremendous progress in increasing vegetative coverage, enhancing carbon sequestration, controlling soil erosion, conservation of biodiversity, etc. For proper implementation and remarkable achievement, a more balanced approach with flexible planning, suitable measures and proper management should be adopted. Meanwhile, the scientific communities need to be more actively involved in execution and assessment of these programs. The environmental impact of the DCBT, the KSDP, and the WCNR deserve more research concern.

The relative contribution of vegetation greening to the hydrological cycle in the Three-North region of China: A modelling analysis

China has implemented a few large-scale afforestation programs in the arid and semi-arid areas, including the north-eastern, northern, and north-western regions, collectively referred to as the Three-North region (TNR), to combat desertification and control dust storms. Although these programs have alleviated environmental problems in the region to a certain extent, the effects of increasing vegetation greenness on the hydrological cycle remain controversial. In this study, the relative effects of afforestation programs on the hydrologic processes in the TNR were identified based on large-scale hydrological modeling and satellite remote sensing data. The model forcing was featured with long-term vegetation dynamics. The study period ranged from 2000 to 2015, during which the greening of vegetation in the TNR was increased after multiple afforestation programs were carried out around 2000. The results indicated that, despite the spatial heterogeneity, the vegetation leaf area index (LAI) exhibited a significant increase across the TNR. Evapotranspiration (ET) increased over the entire region at the rate of 2.9 mm/year from 2000 to 2015, and its spatial pattern was consistent with changes in the LAI and precipitation. However, this does not imply equal contribution by vegetation growth and precipitation change. The results from the simulation scenarios indicated that precipitation change had a more significant influence on the ET, soil moisture and runoff than vegetation growth at the regional scale. Vegetation greening and precipitation increase in the Loess Plateau indicated their approximately equal impacts on ET and soil moisture. Consequently, the hydrological cycle was sensitive to afforestation practices at small-catchment or sub-regional scales where the magnitude of vegetation greening is relatively high. Therefore, the hydrological effect of vegetation greening at large scale may be overestimated by previous studies. To ensure sustainable water resource management at the TNR scale, special attention should be paid to climate change rather than afforestation efforts under the current level of ecological restoration programs.

Contributions of climate change, elevated atmospheric CO2 and human activities to ET and GPP trends in the Three-North Region of China

Quantifying and distinguishing the contributions of climate change, elevated atmospheric CO2 concentration (eCO2) and human activities to evapotranspiration (ET) and gross primary production (GPP) changes is of great significance for assessment of water shortage and land degradation. Based on the Vegetation Interface Processes (VIP) model, the spatial-temporal changes of ET and GPP in the Three-North Region (TNR) of China from 1982 to 2017 were estimated. The results showed that annual ET and GPP increased slightly with a rate of 0.71 mm yr−1 (P<0.001) and 0.002 gC m−2 yr−1 (P<0.001), respectively. The ridge regression presented that the contributions of climate change, eCO2 and human activities to ET and GPP trends were varying noticeably in the four sub-regions, namely: in the Mongolia-Xinjiang Sub-region (MXS), ET and GPP trends were basically attributed to increasing precipitation; in the Loess Plateau Sub-region (LPS), vegetation greening resulted from the Grain to Green Program was the dominant driving factor for GPP enhancement, while the relative contribution of vegetation greening to ET intensifying was lower than the raising net radiation; in the North China Sub-region (NCS), the negative effect of net radiation decline on ET was offset by the positive effect of vegetation greening, -and eCO2 and vegetation greening dominated the upward trend of GPP; in the Northeast China Sub-region (NES), the declines in net radiation and precipitation showed negative impacts on ET and GPP trends. These findings are crucial for better understanding the complicated influences of driving factors on water and carbon cycles over the TNR, which is favorable for evaluation of ecological projects effects and management of water resources.

Vegetation dynamics and their effects on surface water-energy balance over the Three-North Region of China

The Three-North Shelterbelt Project (TNSP) is one of the largest ecological restoration projects of the world. Although its important role in regulating the ecosystem of northern China has been acknowledged, how this project affects the surface water-energy balance deserves further evaluation. This study characterizes spatiotemporal variation of climate variables and vegetation coverage/density over the Three-North Region (TNR) of China using multiple datasets since the implementation of the TNSP. Of particular importance is that effects of vegetation restored during the TNSP on surface water-energy budget are examined for the study domain. Our results show that accompanied by a significant enhancement of vegetation coverage and density in the TNR, its annual air temperature and precipitation have increased 1.46 °C and 89.1 mm, respectively from 1982 to 2015. We find such rise in the air temperature and precipitation plays a positive role in the TNR’s vegetation restoration in a sense that the vegetation dynamics show positive correlation with its regional air temperature and precipitation, while more sensitive to precipitation. We also find carbon sequestration of the TNR increases at the cost of greater water consumption through evapotranspiration since the TNSP commences. In some arid regions, revegetation accelerates the water deficit due to an excessive rate of restoring vegetation; yet, no substantial water imbalance occurs as a result of enhanced precipitation and water use efficiency during this period. Although the solar radiation increases with decreases in surface albedo over the last few decades, our results do not reveal an appreciably increasing trend in the land surface temperature of the TNR. This is because the improved vegetation can assimilate CO2 (mitigating greenhouse gas emissions) and transpire water by photosynthesis, thereby increasing latent heat flux and reducing the warming effect. This study highlights a mixed consequence of the TNSP by inducing both positive and negative effects on the surface water-energy balance over the TNR.

Extended Dependence of the Hydrological Regime on the Land Cover Change in the Three-North Region of China: An Evaluation under Future Climate Conditions

The hydrological regime in arid and semi-arid regions is quite sensitive to climate and land cover changes (LCC). The Three-North region (TNR) in China experiences diverse climate conditions, from arid to humid zones. In this region, substantial LCC has occurred over the past decades due to ecological restoration programs and urban expansion. At a regional scale, the hydrological effects of LCC have been demonstrated to be less observable than the effects of climate change, but it is unclear whether or not the effects of LCC may be intensified by future climate conditions. In this study, we employed remote sensing datasets and a macro-scale hydrological modeling to identify the dependence of the future hydrological regime of the TNR on past LCC. The hydrological effects over the period from 2020–2099 were evaluated based on a Representative Concentration Pathway climate scenario. The results indicated that the forest area increased in the northwest (11,691 km2) and the north (69 km2) of China but declined in the northeast (30,042 km2) over the past three decades. Moreover, the urban area has expanded by 1.3% in the TNR. Under the future climate condition, the hydrological regime will be influenced significantly by LCC. Those changes from 1986 to 2015 may alter the future hydrological cycle mainly by promoting runoff (3.24 mm/year) and decreasing evapotranspiration (3.23 mm/year) over the whole region. The spatial distribution of the effects may be extremely uneven: the effects in humid areas would be stronger than those in other areas. Besides, with rising temperatures and precipitation from 2020 to 2099, the LCC may heighten the risk of dryland expansion and flooding more than climate change alone. Despite uncertainties in the datasets and methods, the regional-scale hydrological model provides new insights into the extended impacts of ecological restoration and urbanization on the hydrological regime of the TNR.

Cloning and Expression Analysis of the Heat-Shock Protein 70 Gene in Eogystia hippophaecolus (Lepidoptera: Cossidae)

Eogystia hippophaecolus is a major borer pest of sea buckthorn in China, damaging the environment and sea buckthorn industry. It is widely distributed in the Three-North region of China, and its larvae are resistant to low temperatures. Because heat-shock protein 70 can repair misfolded proteins under low temperatures, thus preventing cell damage and improving tolerance, we investigated the adaptation of E. hippophaecolus HSP70. We screened the transcriptome of E. hippophaecolus for HSP70 homologs, identified a full-length gene, and cloned to obtain the open reading frame, which was 1896 bp in length and encoded 631 amino acids, with a molecular weight of 69.7 kDa. The amino acid sequence contained three signature sequences of the HSP70 family and a C-terminal cytoplasmic character sequence. A phylogenic tree demonstrated that EhHSP70 has high homology with HSP70 genes from other insect species. We measure expression of the HSP70 gene across tissues when larvae of E. hippophaecolus were cold shocked. We also measured expression during cold shock recovery. EhHSP70 expression varied across tissues at 25 °C, with the highest expression in the midgut. Compared with the control, the expression of EhHSP70 in the cuticle was fourfold higher after a cold shock of — 5 °C for 1 h. EhHSP70 expression was also significantly increased during the 1-h period following recovery from cold shock, then decreased. In summary, cold shock promoted the expression of EhHSP70, which may play an important role in the adaptation mechanism of cold tolerance in E. hippophaecolus larvae.

Detection and attribution of changes in hydrological cycle over the Three-North region of China: Climate change versus afforestation effect

China’s Three-North region (TNR), a typical arid and semiarid area, has experienced substantial land cover (LC) changes since the early 1980s partly due to the implementation of large-scale afforestation programs and to expanding urbanization. Hydrological monitoring and simulations for the past five decades reveal that the TNR might have a trend towards environmental degradation due to decreasing soil moisture and streamflow. A few studies regarding individual basins or local scales have proposed that the drying trend is attributable to climate and LC changes; however, little is known about their relative contributions at the regional scale over the TNR. In this study, we employ the Variable Infiltration Capacity (VIC) model in conjunction with remote-sensing retrieval data sets, to detect the changes in hydrological cycle and to identify the contributions of LC and climate change during 1989–2009. The simulation results demonstrate a slight increase in ET at a rate of 3.26mm per decade over the entire region during 1959–2009. However, ET, runoff and soil moisture exhibit significant decreases after 1989, although their trends have spatial heterogeneities. Sensitivity experiments illustrate that across the TNR, the inter-annual trends in the hydrological regimes can be primarily attributed to the decreasing precipitation which accounts for the ET and runoff declines of 27.5mm and 16.8mm, respectively, for the past two decades. The LC change plays a negligible role. These findings are critical to evaluate the effect of ecological projects (e.g., afforestation practices) and imply the importance of water resources management because of the decreasing water availability in this arid and semiarid region. To reduce modeling uncertainties, high-resolution historical LC data sets and model parameterization on dynamic vegetation should be improved.

Benefit measurement of the soil and water conservation for ecological forestry engineering

Data were collected from Three-north Region, Middle and upper reaches region of Yangtze River and Coastal region. By analysis of factors influencing soil erosion, the longitude, latitude, annual precipitation, and the slope degree were selected as regional independent variables and canopy density and stock litter were selected as independent variables, and integral diffusing models were established for evaluation of the benefit of soil and water conservation of forest. By solving the parameters of models using the package of STATISTICA, the Power function between independent variables and dependent variables was set up. The soil conservation amount of forest and economic values were estimated using the contrast method for the ecological forestry engineering of the above three areas.