Several Asian countries are undergoing rapid economic development driven by diverse factors. This development is leading to continuous land use changes, including deforestation, urbanization, and agricultural conversion. Such transformations threaten essential ecosystem functions and services, like food provision, climate regulation, and cultural benefits. Land-use changes, influenced by economic activities and policies, carry extensive consequences, impacting ecosystem productivity, water resources, and climate stability. Remote sensing technology significantly aids in monitoring and quantifying these changes, offering valuable insights for land management and policy decisions. The NASA Land-Cover and Land-Use Change (LCLUC) Program within NASA’s Earth Science Division program aims to establish global assessments of land changes using space-based methods (https://lcluc.umd.edu/). The South/Southeast Asia Research Initiative (SARI), funded by NASA LCLUC, focuses on advancing LCLUC science in the region and fostering collaborations between US and Asian researchers. Utilizing geospatial data from remote sensing and models, SARI employs a comprehensive approach, considering biophysical and socioeconomic aspects of land systems and their interactions. SARI has been enhancing LCLUC science through science projects, partnerships, training, workshops, and capacity building exchanges since 2015. This Special Issue, stemming from SARI meetings in the Philippines and Malaysia in 2018 and 2019, gathers articles focusing on LCLUC, degradation, and ecosystem services in Asia. Of over 90 submissions, 30 have been accepted, providing insights into these issues and their regional impacts. The articles are summarized into various sub-themes below.
Ecological restoration projects have significantly contributed to the global increase in vegetation cover and the reduction of soil erosion. However, the impact of lithology in the karst ecosystem on changes in soil erosion characteristics during vegetation restoration remains unclear. This study aims to investigate the soil erosion characteristics of hillslopes under different vegetation restoration strategies in the fragile karst areas composed of limestone and dolomite. The restoration strategies mainly include arbor forest (AF), orchard (OC), and grassland (GL), with cropland (CR) as the control. Soil physical-chemical properties and soil erodibility factors (K EPIC, K NOMO) were used to evaluate soil erosion characteristics. The results showed that, in comparison to cropland, both limestone and dolomite in restoration strategies exhibited lower soil bulk density (BD) and soil erodibility K values, as well as higher capillary porosity (CP) and soil water-stable aggregates (WSA). However, the K value of limestone (17.9%) was significantly higher compared to dolomite. Additionally, limestone exhibited significant changes ( p < 0.05) in soil properties, such as BD, organic matter content (OMC), CP, and WSA. Conversely, dolomite did not show significant changes in these soil properties. These findings indicate that vegetation restoration was effective in improving soil structure and erosion resistance, and dolomite exhibit higher stability compared to limestone. Through redundancy analysis, it was observed that soil texture, represented by silt content, was the primary parameter indicating changes in soil erosion characteristics following vegetation modification. The silt content explained 84.4% and 78.2% of the variation in K values for limestone and dolomite, respectively. Moreover, the changes in K values for dolomite were also controlled by OMC, whereas limestone was solely controlled by soil texture. These findings suggest that the interactions between soil properties contribute to the improvement of stability in dolomite. Accordingly, vegetation restoration enhances soil erosion resistance; however, the effectiveness of restoration was controlled by the lithology in the southwestern karst region.
Evaluating the level of green development of cultivated land (GDCL) and its influence mechanism can provide important support for better promoting agricultural green development and rural revitalization. According to the concept of green development, we construct the evaluation system of “adaptability-vitality-resistance (A-V-R)” and explore the spatial and temporal differentiation characteristics and influence mechanism of China’s GDCL in 2000, 2005, 2010, 2015, and 2020 by using the methods of the Comprehensive Evaluation Model, Standard Deviation Ellipse, Theil Index, and Geographic Detector. The results show that: (1) From 2000 to 2020, the level of GDCL in China was low and improved slowly, increasing from 0.264 to 0.293, showing the characteristics of “W” fluctuation, and the focus shifted from Southwest to Northeast. (2) The GDCL in China has obvious spatial dependence, and the evolution of different types of regions has significant path dependence and spatial and temporal inertia. (3) The regional difference in the level of GDCL in China is greater than that among regions. The hierarchical structure characteristics of Northeast Region > Western Region > Central Region > Eastern Region is prominent, and show an overall increasing trend. (4) Human factors greatly impact the level of GDCL. The interaction of driving factors forms a complex multi-resultant force to jointly build a comprehensive action mechanism of GDCL level driven by demand, economy, science and technology, and ecological block.
Soil erosion control is critical to global food production and ecosystem health. The Mediterranean region is particularly concerned because it is prone to erosion and is expected to be strongly affected by climatic and anthropogenic changes. In this paper we explore how land use and management (LUM) can mitigate climate change impacts and increase agricultural attractiveness in pasture-dominated Mediterranean mountain environments. For that, soil erosion for different combinations of current and plausible future climate and LUM conditions were simulated on a small watershed located in eastern Sicily (Italy) using the LandSoil model. LUM scenarios were established as a modulation of environmental protection and agricultural production/diversification. The main management distinctions tested in this paper included intensive vs. extensive practices for pasture, and conventional vs. conservative practices for cereals and orchards. Simulations showed that the impact of climate change was very low and not significant in the studied watershed. Our results also emphasised that agricultural diversification coupled with adaptations in practices and management can improve the attractiveness of agriculture in pasture-dominated environments while maintaining soil protection at an acceptable level.
It is challenging for a single development subject to complete complex scientific research tasks due to the peculiarities of saline-alkali land. Collaborative innovation and cooperation between development subjects are increasingly vital. This paper first constructs an undirected weighted collaborative innovation network from the upstream, midstream, and downstream levels of technological innovation for saline-alkali land development, analyzing the network’s structural characteristics and spatial distribution features. Then uses ERGM to explore the internal and external driving mechanism for network formation from network self-organization, subject characteristics, and exogenous environmental factors. The results demonstrate that the distribution of collaborative innovation networks for saline-alkali land development is relatively uniform. However, there are also clusters, and the clusters are mostly centered on universities and scientific research institutions. Both the development subjects and clusters present regional features. Centrality and transitivity are crucial in the internal driving mechanism. In the external driving mechanism, the Matthew effect is modest, and the Homozygous effect is considerable; Organizational and technical proximity play a positive role; Geographical and institutional proximity play a blocking role. This study also provides practical enlightenment for encouraging horizontal and vertical collaborative innovation of sustainable development of saline-alkali land.
Water resources management is fundamental for rural communities in drylands. Water Harvesting Technologies (WHT) intercept and store the excess rainfall (surface runoff) in soils for increased plant available water and agricultural productivity. The so-called ‘Marab’ WHT was initially developed by Middle Eastern agro-pastoralists that reside or commute in semi-arid and arid rangelands. The Marab WHT is a macro-catchment measure consisting of earth dams and stone spillways along the contours of a lowland depression or floodplain. Dependent on the local context (i.e. climate, soil, management, etc.) the established Marabs show highly-variable effectiveness. This study aims at filling the knowledge gap on the WHT’s performance in changing environments by simulating its hydro-agrological effects for different soils and climatic conditions using the AquaCrop model. A case study performed for a Jordanian Marab over three seasons (2019-2022) confirms its huge improvement potential for barley production. Through Marab-farming, barley production reached 8.37 t ha -1 on average, versus highly variable 0.34 t ha -1 without the WHT. The simulation-based assessment of soil textures identified that silty soils have the largest potential for producing up to 9.25 t ha -1 barley, compared to 6.60 t ha -1 produced in clay soils. Assessing different climate scenarios, a slight increase in daily average temperatures (+ 0.5°C) led to a considerable production decline of 4-8%, while a significant reduction of precipitation (-20%) decreased biomass production by a similar rate (4-10%). This underlines the robustness of the ‘Marab’ WHT to rainfall amount variation. However, simulations also highlight the sensitivity of timing and frequency of flood events: removing the last and the first flood event reduced biomass production by approximately 50% and 80% respectively, while the barley fails to develop if both events were suppressed.
Soil salinization is a serious problem leading to ecological degradation. Melia azedarach is highly salt-tolerant, and its application to saline-alkali land is a promising strategy for restoring degraded lands. In this study, we analyzed the soil properties and metabolome of M. azedarach roots grown in low- (< 3 g/kg; L), medium- (5~8 g/kg; M), and high- (> 10 g/kg; H) salinity soils to explore the amelioration effect and adaptation mechanism of M. azedarach to soils with differential salinity. Cultivation of M. azedarach was associated with a decrease in the concentration of Na + and increases in organic matter content and alkaline phosphatase and urease activities in the rhizosphere soil. The metabolome analysis revealed that a total of 382 (ESI+) and 277 (ESI-) differential metabolites (DEMs) were detected. The number of DEMs in roots rose with increased soil salinity, such as sugars and flavonoids in H vs. L, and amino acids in M vs. L. The most up-regulated DEMs were 13-S-hydroxyoctadecadienoic acid, 2’-Deoxyuridine and 20-hydroxyleukotriene B4. Combined analysis of soil properties and M. azedarach DEMs indicated that alkaline phosphatase activity was positively correlated with traumatic acid concentration. Taken together, these results indicate that M. azedarach has the potential to reduce soil salinity and enhance soil enzyme activity, and it can adapt to salt stress by regulating metabolites like sugars, amino acids, and flavonoids . This study provided a basis for understanding the mechanism underlying the adaptation of M. azedarach to saline-alkali soil and its amelioration.
Northeast China is experiencing severe soil erosion, resulting in land degradation and nutrient loss. Among them, hydraulic erosion poses the greatest threat to food security. Combining various multi-source data, we applied the modified soil erosion equation (RUSLE) to evaluate hydraulic erosion modulus in Northeast China’s black soil region(1985–2021). We used the threshold segmentation and residual analysis method to quantify the relative roles of climate change and human activities on hydraulic erosion. The outcomes were presented below: (1) The yearly mean hydraulic erosion modulus was 804.78 t·km -2·a -1 and decreases significantly with a slope of -11.114 t·km -2·a -1. The area with significant growth in erosion modulus covered 23.77% of the overall area and was mainly spread in grassland and farmland. The areas with a significant decrease in erosion modulus covered 19.82% and were mainly spread in natural forests. (2) In areas with significant increases in erosion, 20.39% of the total area was attributed to anthropogenic factors and 3.38% of the total area was attributed to natural factors. In areas where soil erosion was significantly reduced, 17.67% and 2.15% were attributed to ecological restoration and natural factors, respectively. (3) Deforestation, grassland degradation, and unreasonable farming still exist. The area of sloping cropland (≥6°) increased by 133.9 km 2 per year, and sloping land erosion increased by 0.187 · 10 10 t per year. The focus of soil erosion prevention and control in northeast China is ecological restoration of grasslands, sloping land management, and conservation tillage.
The limited land is under unprecedented pressure from production, living and ecology. In order to evaluate the land pressure in the Yangtze River Delta region in 1995, 2000, 2005, 2010, 2015, and 2020 from the perspective of production, living, and ecology. This study builds a land pressure evaluation index system based on a fuzzy comprehensive evaluation model using multi-source and multi-scale data. In order to investigate trade-offs and synergies among production, living, and ecology pressures, we use the mechanical equilibrium model in physics. We then analyze land pressure model reliability and uncertainty using Monte Carlo simulations. The results show that (1) Our model can effectively reveal the level of land pressure and reflect the land pressure geographical pattern of “high in the east and low in the west, high in the south and low in the north” that characterizes the Yangtze River Delta region. (2) While living and ecology pressures are tending to rise, production pressures are tending to decrease. (3) Except for Shanghai, the trade-off areas are primarily concentrated in economically successful regions with high production and living pressure and low ecology pressure. The coordinated areas are primarily found in northern Jiangsu Province and northern Anhui Province.
Ephemeral gully erosion is a primary mode of soil erosion that is highly visible, affecting soil productivity and restricting land use. Watershed is the basic unit of soil erosion control; existing research has focused on several typical ephemeral gullies or slopes, which do not fully display changes in ephemeral gullies at a watershed scale. This study analyzed the spatial-temporal evolution and development rate of ephemeral gully erosion at the watershed scale on the Loess Plateau from 2009 to 2021 using remote sensing images (0.5 m resolution), unmanned aerial vehicles (UAV), and field investigations. The results revealed that: (1) most ephemeral gullies occurred in southwestern parts of the watershed, with many hills and large slope gradients; (2) average growth rates of each ephemeral gully frequency, length, density, dissection degree, and width were 2.87 km 2 y –1, 1.66 m y –1, 0.12 km km –2 y –1, 0.0125% y –1, and 0.04 m y –1 , respectively; (3) ephemeral gully erosion volume ( V) and length ( L) had a good power function relationship: V = 0 . 0842 L 1 . 1932 ( R 2 = 0 . 80 ) . The root mean square error (RMSE) and coefficient of determination (R 2) between the measured and predicted ephemeral gully volumes suggest that the V–L relationship has a good predictive ability for ephemeral gully volume. Thus, the V–L model was used to evaluate the development rate of ephemeral gully erosion volume in small watersheds from 2009 to 2021, revealing an average value of 743.20 m 3 y –1. This study proposed a feasible model for assessing ephemeral gully volume and volume changes at a watershed scale using high-resolution remote sensing images, providing a reference for understanding the development of ephemeral gully erosion in small watersheds over time.
A high stocking rate can intensify wind erosion in grasslands, and strong wind can carry away soil surface particles and their nutrients, which leads to soil barrenness. In this research, the dust flux, total carbon (TC) and total nitrogen (TN) contents and fluxes of aeolian sediment were computed in the non-growing season (mid-October to mid-April of the following year) and growing season (mid-April to mid-October) from 2018 to 2020 at a long-term grazing gradient experiment platform and wind-erosion monitoring experiment in a desert steppe in Inner Mongolia, China. The results were as follows, 1) with the increasing of stocking rate, the fluxes of aeolian sediment at 10 cm (H10), 30 cm (H30), and 100 cm (H100) were greatly increased ( P<0.05). Aeolian sediment fluxes followed the order control (CK) < light stocking rate (LG) < moderate stocking rate (MG) < heavy stocking rate (HG). 2) TC and TN contents of aeolian sediment reflected stocking rates and followed the order CK>LG>MG>HG, and also reflected aeolian sediment collection height, as H10P>0.05). TC and TN contents in HG at different heights reduced by 31.1% and 25.9% on average in comparison to the CK in the non-growing season, and by 30.1% and 25.0% in the growing season. TC loss was higher than TN loss. Overall, as stocking rate increased, wind erosion increased, leading to the loss of soil nutrients and significant loss of the carbon pool in this desert steppe.
Abstract Qinghai-Tibetan Plateau is an important ecological security barrier in China, and alpine ecosystem presents a trend of overall improvement under the influence of climate change and human activities, yet there are localized deteriorations. In order to improve the ecological function of the Tibetan Plateau, large-scale ecological restoration projects (ERPs) have been carried out in Tibetan Plateau over the past 30 years. From following the footstep of national ecological constructions to the implementation of projects specific to the plateau characteristics, the ERP of the plateau can be divided into three stages. Major ERPs focusing on four types of projects, i.e. forest protection and construction, grassland protection and construction, water and soil erosion control and desertification land management, with a total area of 850,000km 2 across the Qinghai-Tibetan Plateau. The positive effect at sampling quadrat scale has been widely verified, and the responses of productivity and species diversity were inconsistent. The positive effect at the regional scale gradually emerges, yet the spatial difference is significant, and the quantification of driving forces is an important prerequisite. The positive and negative effects of existing ERP on biodiversity conservation are revealed, for instance, there is a significant increase of rare wild animals in natural reserves and in artificially planted areas it failed to effectively curb the loss of animal and plant diversity. The long-term effects of various ERPs on the biodiversity should be taken into account so as to optimize the ecological measures and build a sustainable management model after project restoration. By summarizing the achievements and problems of ERP across the Qinghai-Tibetan Plateau in the past 30 years, we proposed to set stepwise ecological restoration and management scheme by different restoration goals and reference modes in three stages, i.e. “Environmental treatment—Ecological restoration projects—Adaptive management”.
Permafrost regions are under particular pressure from climate change resulting in widespread landscape changes, which impact also freshwater chemistry. We investigated a snapshot of hydrochemistry in various freshwater environments in the lower Kolyma river basin (North-East Siberia, continuous permafrost zone) to explore the mobility of metals, metalloids and non-metals resulting from permafrost thaw. Particular attention was focused on heavy metals as contaminants potentially released from the secondary source in the permafrozen Yedoma complex. Permafrost creeks represented the Mg-Ca-Na-HCO 3-Cl-SO 4 ionic water type (with mineralisation in the range 600-800 mg/L), while permafrost ice and thermokarst lake waters were the HCO 3-Ca-Mg type. Multiple heavy metals (As, Cu, Co, Mn and Ni) showed much higher dissolved phase concentrations in permafrost creeks and ice than in Kolyma and its tributaries, and only in the permafrost samples and one Kolyma tributary have we detected dissolved Ti or Hg. In thermokarst lakes, several metal and metalloid dissolved concentrations increased with water depth (Fe, Mn, Ni and Zn - in both lakes; Al, Cu, K, Sb, Sr and Pb in either lake), reaching 1370 µg/L Cu, 4610 µg/L Mn, and 687 µg/L Zn in the bottom water layers. Permafrost-related waters were also enriched in dissolved phosphorus (up to 512 µg/L in Yedoma-fed creeks). The impact of permafrost thaw on river and lake water chemistry is a complex problem which needs to be considered both in the context of legacy permafrost shrinkage and the interference of the deepening active layer with newly deposited anthropogenic contaminants.
：Vegetation blanket restoration techniques of different materials in mine drainage field provide different environments for plant growth, but effects of vegetation blanket cover on soil microbial community structure and their diversity characteristics were not well known， especially in arid areas. In this study, high-throughput sequencing was used on the study site, located at Dafeng Mine, the Helan Mountains, Ningxia, China. Soil microbial communities were analyzed under four different treatments: Straw, Straw-Coir, Coir vegetation blanket types, and a bare soil control. The results showed that the contents of soil total nitrogen, available potassium, urease, and catalase were significantly increased in different types of vegetation blankets. High-throughput sequencing showed that the straw vegetation blanket increased bacterial diversity while the coir vegetation blanket increased fungal diversity. The dominant bacterial phyla were Proteobacteria, Bacteroidetes, Actinobacteria, and Chloroflexi, whose main influencing factors were total nitrogen, catalase, urease, and protease. The dominant fungal phylum was Ascomycota, whose main influencing factors were alkaline phosphatase, soil organic carbon, total nitrogen, and electrical conductance. These results indicate that vegetation blanket cover can improve the physicochemical properties of soil, increase the diversity and richness of soil microorganisms, and improve the structural composition of the community, thus improving the soil environment in the mining areas in arid regions, while laying a good foundation for further restoration measures.
On 19 September 2021, a new monogenetic volcano (Tajogaite) erupted on the island of La Palma (Canary Islands, Spain). After 86 days of strombolian eruption, with emissions of volcanic material, a pyroclastic cone 200 m high and 800 m in diameter was formed. Successive lava flows descended the western slopes and reached the sea on 29 September. On descending the coastal cliffs and entering the sea, the lava flows formed two lava deltas of 75 and 5 ha, on the submarine island shelf, backed by fossilized coastal cliffs. This work presents an approach, using comparative and numerical methods, to estimate the geoheritage value and support the conservation of a new volcanic landscape in an island territory with high anthropic pressure on land uses. In a first phase, a cartographic inventory was made of all the volcanic formations similar to the new volcano in the geological domain of the Canary Islands. In a second phase, their representativeness (A), rarity (R), diversity (D), integrity (I) and observability (O) was quantitatively measured by means of dimensional estimators. The results obtained show that the new volcano presents a geological value of the first order in the context of the Canary Islands, which is one of the most prominent hot-spot archipelago worldwide. Its value is based above all on its high conservation state with respect to the similar volcanoes in the Canary Islands. The high mismatch found between the intrinsic geological value and the environmental protection of this area, justifies the development and application of urgent basic guidelines for its protection, as well as the promotion of geotourism as opposed to alternative land uses.
Global food demand is expected to increase in the next decades pushing agricultural expansion and deforestation. However, food production in agricultural lands is just one dimension of food security, to which forest goods and services also contribute. In this paper, we aimed to explore the relationship between forest cover and food security. We hypothesised that food security is improved by both human-made and green infrastructure combined. To test this relationship, we explore the relationships between forest cover and a multidimensional index of food security that included both socioeconomic and natural variables taken from Brazilian official databases for 1,141 municipalities of the Brazilian Caatinga (a seasonally tropical dry forest). The index was formed by 12 principal components axes (12 PCs) and we found that financial poverty (PC 1) and economic inequality (PC 2) were the main determinants of food insecurity in Caatinga. We found that lowest food security values were found in two contrasting contexts: one is represented by poor and unequal municipalities with high forest cover while the other refers to poor and less unequal municipalities but with little forest cover. Municipalities with intermediate levels of forest cover had slightly higher food security, a consistent pattern across time (2006 and 2017). Win-win scenarios where both forest cover and food security increased with time were almost as common as lose-lose situations (25% and 22% respectively). This suggests a sort of balance between forests and human-made land uses and reinforces that natural capital contributes to food security. Zero-hunger is a main issue for sustainable development goals and our results adds to the notion that both sustainable use of forests and socioeconomic improvements must coexist rather than being treated as antagonistic policies.
Soil phosphorus (P) is an essential nutrient that controls wetland productivity and ecological functions. However, the effects of soil P forms on P availability during wetland degradation are relatively unknown. Soil samples from differently degraded marshes, including relatively pristine marsh (RPM), lightly degraded marsh (LDM), moderately degraded marsh (MDM), and heavily degraded marsh (HDM), were collected to investigate the changes in soil P forms and its regulation on P availability in the Zoige Plateau, China. We observed that compared with RPM, the main changes in total P concentration were a significant increase of 31.6%–44.2% in the 0–30 cm soil layers of LDM and MDM, and the available P concentration increased in LDM and MDM but decreased in HDM with a lower P activation coefficient. Marsh degradation increased the concentration and proportion of dicalcium phosphates, P occluded in iron hydroxides, and organic P but decreased those of iron oxide surfaces adsorbed P and apatite P. Soil available P was mainly related to organic P and P non-occluded in iron oxide minerals that might also be non-negligible direct source of available P. The transformation from apatite P to organic P was an important regulation mechanism of P availability in soils during marsh degradation. This study revealed the risk of P limitation in heavily degraded marsh soils and established the mechanism by which marsh degradation significantly influences soil P availability. Therefore, some measure of on improving P availability should be implement for the ecological restoration of heavily degraded marsh in the future, such as grazing exclusion and the application of organic fertiliser.
Snow avalanches are a major component of the mountain cryosphere that frequently create a menace for the road network. Deposit characteristics determine the extent of damage and disruption to communication networks, but the factors controlling snow-deposit volumes remain largely unknown. This study investigates the influence of meteorological and snowpack conditions on snow-avalanche deposits and road-network vulnerability based on 1986 deposit volumes from 182 paths located in two regions of the French Alps between 2003 and 2017: Guil and Haute-Maurienne valleys. During the period, 195 avalanches impacted the road network in these areas, leading to major disruptions. In Haute-Maurienne, correlations between deposit volumes and meteorological and snowpack conditions are high in winter. However, the relationships differ with path elevation and orientation. Results do not show any significant relationship between volumes and meteorological or snowpack conditions for the spring season. Focusing on deposits that disturbed the road network, winter and spring reveal a distinct influence of meteorological and snow variables compared to the overall data set, with snowfall intensity as the predominant control variable of deposit volumes leading to road cuts. When the same analysis is conducted by considering Guil valley separately or by aggregating Haute-Maurienne with Guil valley area data, results do not show any significant relationship, highlighting the specific regional nature of relations between deposit volumes and meteorological and snowpack conditions.