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Global drylands face a host of urgent human and environmental challenges with far-reaching impacts. Improving smallholder agriculture remains a key development pathway to tackle these challenges. The dryland development paradigm (DDP), introduced in 2007, presented a highly influential framework for dryland development based on systems research. This paper empirically derives a new, updated DDP. It assesses recent, cutting-edge dryland science, combining literature review with qualitative and quantitative analysis of research published by the world's largest dryland science and development research initiative. The new DDP comprises eight characteristics that are distilled into three integrative principles: Unpack, Traverse and Share. The new DDP is applied and tested to identify key dryland knowledge and development gaps. A future research agenda is then elucidated, grounded in a research in development approach, in which research anchored in the three integrative principles is embedded within the context it seeks to improve. Supported by greater trans-disciplinarity and knowledge co-production, operationalization of the new DDP can deliver both novel scientific insights and development impact in line with the aspirations of the 2030 Sustainable Development Goals. © 2017 The Authors. Land Degradation & Development Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Aridity is a climatic phenomenon characterized by shortage of water availability in a given time and space resulting in low moisture and reduced carrying capacity of ecosystems. It is represented by a numerical indicator known as Aridity Index (AI), a function of rainfall and temperature. Aridification is a slow and steady effect of climate change and assessing its spread and change is vital in context of global climatic variations. Aridity is predominantly significant for agrarian countries like India, where a slight rise in drylands area can have a significant impact on the economy and community sustenance. AI is an inclusive indicator of climatic conditions in most arid and semi-arid regions. It helps in identifying and interpreting large scale trend in temperature and precipitation; and thus, classifying region into different climatic classes. The present study assessed long-term AI based on precipitation and temperature data obtained from the India Meteorological Department at the resolution of 1 × 1 degree for years 1969–2017. AI is estimated as a ratio of mean precipitation to mean potential evapotranspiration, calculated using Thornthwaite method. The results highlight the trend of aridity over pan-India with Innovative Trend Analysis and Mann–Kendall test. The study concludes that there is a relatively slow, however steadily progressive drier conditions being established in most of the regions. A shift from 'Semi-arid' towards 'Arid' class appeared in central mainland. The north-eastern Himalaya showed decrease in humid conditions ('Humid' to 'Sub-humid'). The study implies that there is a rising aridity trend over the years due to changing climatic conditions. The shifts in aridity can have serious implications on agriculture, long-term water resource utilization and land use management plans. Our results have scope for future landscape management studies in drylands and better adaptation methods in arid regions. [ABSTRACT FROM AUTHOR]

Abstract Past water resource developments in dryland regions rarely estimated the full suite of environmental and social impacts arising from damming and diverting water for food production. Nowadays there is a greater focus on sustainable resource development which considers the economic, social and environmental costs and benefits. A challenge is to apply tools and methods which can capture the often disparate knowledge and data describing many costs and benefits. This paper describes a proof of concept application of a large Bayesian Decision Net to estimate the total utility of water resource development according to criteria of social, economic and environmental sustainability. We focus on two water-scarce catchments in remote northern Australia which are under investigation for development. The study catchments contain a diverse set of ecosystem services and socio-cultural values, including important Indigenous values and high value freshwater ecosystems. The Bayesian Decision Net was shown to have many properties that made it useful for performing a social, economic and environmental sustainability assessment, in particular its ease of construction; its ability to handle quantitative and qualitative data types; its preservation of system knowledge and; its ease of use in aiding decision making. From the perspective of the sustainability assessment in our case study, the total utility of water resource development for new irrigation is negative in both the studied catchments. The overall utility of water resource development could be positive if irrigation development is highly sensitive to the environment and there are very low environmental impacts, and much higher net economic returns to irrigators eventuate, possibly through higher commodity prices, lower capital costs of irrigation development or some combination of both. Highlights • Development of water resources involves trade-offs between economy and environment. • Integrated social-environment-economy sustainability (SEES) assessments support trade-offs analyses. • Bayesian Decision Networks (BDNs) support SEES assessments with diverse data types. • BDN applied to irrigation development scenarios of two remote catchments in north Australia. • The economic and ecosystem service benefits of the case study irrigation developments are questionable. [ABSTRACT FROM AUTHOR]

Exploring the future trends of land use/land cover (LULC) changes is significant for the sustainable development of a region. The simulation and prediction of LULC in a large-scale basin in an arid zone can help the future land management planning and rational allocation of resources in this ecologically fragile region. Using the whole Ili-Balkhash Basin as the study area, the patch-generating land use simulation (PLUS) model and a combination of PLUS and Markov predictions (PLUS–Markov) were used to simulate and predict land use in 2020 based on the assessment of the accuracy of LULC classification in the global dataset. The accuracy of simulations and predictions using the model were measured for LULC data covering different time periods. Model settings with better simulation results were selected for simulating and predicting possible future land use conditions in the basin. The future predictions for 2025 and 2030, which are based on historical land change characteristics, indicate that the overall future spatial pattern of LULC in the basin remains relatively stable in general without the influence of other external factors. Over the time scale of the future five years, the expansion of croplands and barren areas in the basin primarily stems from the loss of grasslands. Approximately 48% of the converted grassland areas are transformed into croplands, while around 40% are converted into barren areas. In the longer time scale of the future decade, the conversion of grasslands to croplands in the basin is also evident. However, the expansion phenomenon of urban and built-up lands at the expense of croplands is more significant, with approximately 774.2 km2 of croplands developing into urban and built-up lands. This work provides an effective new approach for simulating and predicting LULC in data-deficient basins at a large scale in arid regions, thereby establishing a foundation for future research on the impact of human activities on basin hydrology and related studies. [ABSTRACT FROM AUTHOR]

In semi-arid regions, interactions between biophysical and socio-economic variables are complex. Such interactions and their respective variables significantly alter land use and land cover, degrade landscape's structure, and impede the efficacy of the adopted land management interventions. This scenario is particularly prevalent in communal land tenure system or areas managed by a hybrid of traditional and state led institutions. Hence, this study sought to investigate the impacts of land use and land cover changes (LULCCs) on land degradation (LD) under communal rural districts, and the key drivers of habitat fragmentation in the Greater Sekhukhune District Municipality (GSDM), South Africa. The study used the wet and dry season multi-temporal remotely sensed image data, key-informant interviews, and workshop with tribal council to determine the major drivers of LULCC and LD. Results revealed that mines and quarries, subsistence and commercial cultivation, and thicket/dense bush LULCs declined significantly during the study period. These LULCs mostly declined in wet season, with loss in vegetation cover highly prevalent. Specifically, the highest conversions were from shrub/grassland to bare soil, thicket/dense bush to shrub/grassland, and shrub/grassland to residential, respectively. Generally, LULCC affected vegetation productivity within the study area, with increased negative NDVI values observed during the dry season. The findings from key informants and the tribal council workshop emphasized that soil erosion, abandonment of cropland, and injudicious land use (i.e. overgrazing and consequent bush encroachment) have severely degraded the land. The study also established that the degrading land can be attributed to the weakening local communal land management system, particularly the weakening tribal councils. The study recommends an urgent need for collaborative (i.e. government, tribal authorities, and land users) land management through designing relevant multi-stakeholder LD mitigation measures. [ABSTRACT FROM AUTHOR]

Wind erosion and resultant dust emissions create significant risks for land degradation and ecosystem health in arid and semi-arid regions. In these regions, fallowing constitutes a major component of conventional agriculture. The present study was conducted to determine wind erosion quantities and agricultural activity-induced mass transport from fallow lands and to assess the correlations of mass transport with climate and soil characteristics. Experiments were conducted over the fallow lands of two adjacent agricultural enterprises (Altinova and Gözlü, Turkey). Sediment flux was measured with passive traps in wet and dry seasons (QtWET and QtDRY). Mass transport in wet and dry seasons was respectively measured as 11.38 and 11.40 kg/ha in Altinova and as 31.61 and 19.71 kg/ha in Gözlü. Both the differences between mass transport of the enterprises and the differences between QtWET and QtDRY of each enterprise were found to be significant (P < 0.05). Pearson's correlation analysis for the correlations of mass transport with soil characteristics revealed significant correlations with electrical conductivity and soil lime content (r = 0.721 and -0.635) (P < 0.05). Total mass transport from the fallow lands of both enterprises throughout a 7-month period of measurement was estimated at 600 t. Based on current findings it was concluded that fallowing should be abandoned and sustainable soil and land management practices from conventional agriculture like minimum tillage or crop rotations should be introduced. [ABSTRACT FROM AUTHOR]

The study evaluated patterns of land use and land cover (LULC) change in the Zambezi Region, Namibia between 1984 and 2010 using geospatial tools. Spatio-temporal dynamics of LULC changes were quantified using the post classification change detection method. The images were classified into five land use and land cover classes: forest land, shrub land, bare land, crop/grass land and other land. Landscape metrics were calculated using Fragstats to understand the landscape patterns and structural integrity of the landscape. The results showed that political transition (before and after independence) has resulted in dramatic decreases in patch density and increases in the interspersion and juxtaposition index values. The general pattern of LULC showed that the communal area compared to protected area became structurally diverse and ecologically more fragmented from 1984 to 2010. This study provides a foundation and baseline data demonstrating LULC alteration and landscape context suitable for monitoring future changes of protected and communal areas. Our approach is a novel way to assess the drivers and patterns of LULC under different land tenure types for natural resources conservation and sustainable land management in the dry lands of Southern Africa. [ABSTRACT FROM AUTHOR]

In arid and semi-arid regions, unregulated land use changes as a result of poor planning, and the expansion of agricultural and livestock activities increase the risk of desertification and other potentially severe environmental impacts. Several consequences of improper land management practices are soil deterioration and erosion, which may be intensified by meteorological events. This paper presents a historical evaluation of the temporal and spatial evolution of soil deterioration in the southern Chihuahuan Desert in Mexico. A multi-temporal analysis of the study area during the 1995–2016 period was carried out using satellite data (Landsat series). Two seasons were analyzed to determine the influence of external events such as rainfall and wind: dry and rainy. The identification of soil conditions was based on the Brightness Index (BI) considering the complete satellite data set. The soil conditions were classified into five categories according to their reflectance values: highly deteriorated, deteriorated, in the process of being deteriorated, in good condition and other (clouds, water, non-soil). The change detection maps clearly show a growing trend wherein areas of deteriorated and eroded soil increase over time. Agriculture and strong winds are the two main factors involved in the soil deterioration process of the study region. • Deficient agricultural practices and strong winds precursors to desertification. • Spatial-temporal identification of deteriorated soil in arid/semi-arid zones. • Spectral analysis based method for categorization of soil conditions. • Comparative analysis of sensitivity in rainy and dry seasons. [ABSTRACT FROM AUTHOR]

Drylands occupy more than 80 % of Kenya's total land mass and contribute immensely to the national economy and society through agriculture, livestock production, tourism, and wild product harvesting. Dryland ecosystems are areas of high climate variability making them vulnerable to the threats of land degradation. Consequently, agropastoralists inhabiting these ecosystems develop mechanisms and technologies to cope with the impacts of climate variability. This study is aimed to; (1) determine what agropastoralists inhabiting a semi-arid ecosystem in Kenya attribute to be the causes and indicators of land degradation, (2) document sustainable land management (SLM) technologies being undertaken to combat land degradation, and (3) identify the factors that influence the choice of these SLM technologies. Vegetation change from preferred indigenous forage grass species to woody vegetation was cited as the main indicator of land degradation. Land degradation was attributed to recurrent droughts and low amounts of rainfall, overgrazing, and unsustainable harvesting of trees for fuelwood production. However, despite the challenges posed by climate variability and recurrent droughts, the local community is engaging in simple SLM technologies including grass reseeding, rainwater harvesting and soil conservation, and dryland agroforestry as a holistic approach combating land degradation and improving their rural livelihoods. The choice of these SLM technologies was mainly driven by their additional benefits to combating land degradation. In conclusion, promoting such simple SLM technologies can help reverse the land degradation trend, improve agricultural production, food security including access to food, and subsequently improve livelihoods of communities inhabiting dryland ecosystems. [ABSTRACT FROM AUTHOR]

Accurate prediction and characterization of the spatial distribution and temporal variation of soil water is indispensable to optimize the use and management of land within dry areas, which suffer from limited arable land and water resources. The objective of this research is to examine the effect of hillslope position and characteristics on soil properties and variation of soil moisture in an arid to semiarid region. Five transects representing toposequences in the transitional Arid to Semiarid Mediterranean region of Jordan were selected to study the effect of hillslope position on soil properties and variation of soil moisture. Four sites representing different hillslope positions were chosen within each transect from the summit down to the toeslope. Soil profile, at each position, was described and sampled for laboratory analyses. Moisture content at different depths was monitored during the rainy season. The results indicated a systematic relationship between topographic characteristics (hillslope position, slope steepness, and curvature) and the particle size distribution. Soil erodibility was found to be indirectly related to topographic position as extrapolated from the consistent relationship with clay content. Soil moisture content was related to the topographic position, the variation in clay content, and vegetation condition. The topographic position was found to govern the flow of water from upper to lower positions, resulting in higher moisture availability at lower positions. The variations of other parameters were not only related to the topographic position of particular soil, but also to the characteristics of the soil at the upper positions, and to the sequence in which that soil is positioned in the toposequence. Understanding the distribution of soil properties and their relationship along the soil-landscape continuum, which is unique to this environment, should improve the prediction of soil properties and improve plans to better manage arid land. [ABSTRACT FROM AUTHOR]

Aim Savannas and seasonally-dry ecosystems cover a significant part of the world's land surface. If undisturbed, these ecosystems might be expected to show a net uptake of methane (CH4) and a limited emission of nitrous oxide (N2O). Land management has the potential to change dramatically the characteristics and gas exchange of ecosystems. The present work investigates the contribution of warm climate seasonally-dry ecosystems to the atmospheric concentration of nitrous oxide and methane, and analyses the impact of land-use change on N2O and CH4 fluxes from the ecosystems in question. Location Flux data reviewed here were collected from the literature; they come from savannas and seasonally-dry ecosystems in warm climatic regions, including South America, India, Australasia and Mediterranean areas. Methods Data on gas fluxes were collected from the literature. Two factors were considered as determinants of the variation in gas fluxes: land management and season. Land management was grouped into: (1) control, (2) ‘burned only’ and (3) managed ecosystems. The season was categorized as dry or wet. In order to avoid the possibility that the influence of soil properties on gas fluxes might confound any differences caused by land management, sites were grouped in homogeneous clusters on the basis of soil properties, using multivariate analyses. Inter- and intra-cluster analysis of gas fluxes were performed, taking into account the effects of season, land management and main vegetation types. Results Soils were often acid and nutrient-poor, with low water retention. N2O emissions were generally very low (median flux 0.32 mg N2O m−2 day−1), and no significant differences were observed between woodland savannas and managed savannas. The highest fluxes (up to 12.9 mg N2O m−2 day−1) were those on relatively fertile soils with high air-filled porosity and water retention. The effect of season on N2O production was evident only when sites were separated in homogeneous groups on the basis of soil properties. CH4 fluxes varied over a wide range (−22.9 to 3.15 mg CH4 m−2 day−1, where the negative sign denotes removal of gas from the atmosphere), with an annual average daily flux of −0.48 ± 0.96 (SD) mg CH4 m−2 day−1 in undisturbed (control) sites. Land-use change dramatically reduced this CH4 sink. Managed sites were weak sinks of CH4 in the dry season and became sources of CH4 in the wet season. This was particularly evident for pastures. Burning alone did not reduce soil net CH4 oxidation, but decreased N2O production. Main conclusions Despite the low potential for N2O production, both in natural and managed conditions, tropical seasonally-dry ecosystems represent a significant source of N2O (4.4 Tg N2O year−1) on a global scale, as a consequence of the large area they occupy. The same environments represent a potential CH4 sink of 5.17 Tg CH4 year−1. However, assuming that c. 30% of the tropical land is converted to different uses, the sink would be reduced to 3.2 Tg CH4 year−1. The limited information on fluxes from Mediterranean ecosystems does not allow a meaningful scaling up. [ABSTRACT FROM AUTHOR]

Background: Land use change plays a vital role in global carbon dynamics. Understanding land use change impact on soil carbon stock is crucial for implementing land use management to increase carbon stock and reducing carbon emission. Therefore, the objective of our study was to determine land use change and to assess its effect on soil carbon stock in semi-arid part of Rajasthan, India. Landsat temporal satellite data of Pushkar valley region of Rajasthan acquired on 1993, 2003, and 2014 were analyzed to assess land use change. Internal trading of land use was depicted through matrices. Soil organic carbon (SOC) stock was calculated for soil to a depth of 30 cm in each land use type in 2014 using field data collection. The SOC stock for previous years was estimated using stock change factor. The effect of land use change on SOC stock was determined by calculating change in SOC stock (t/ha) by deducting the base-year SOC stock from the final year stock of a particular land use conversion. Results: The total area under agricultural lands was increased by 32.14% while that under forest was decreased by 23.14% during the time period of 1993–2014. Overall land use change shows that in both the periods (1993–2003 and 2003–2014), 7% of forest area was converted to agricultural land and about 15% changes occurred among agricultural land. In 1993–2003, changes among agricultural land led to maximum loss of soil carbon, i.e., 4.88 Mt C and during 2003–2014, conversion of forest to agricultural land led to loss in 3.16 Mt C. Conclusion: There was a continuous decrease in forest area and increase in cultivated area in each time period. Land use change led to alteration in carbon equity in soil due to change or loss in vegetation. Overall, we can conclude that the internal trading of land use area during the 10-year period (1993–2003) led to net loss of SOC stock by 8.29 Mt C. Similarly, land use change during 11-year period (2003–2014) caused net loss of SOC by 2.76 Mt C. Efforts should be made to implement proper land use management practices to enhance the SOC content. [ABSTRACT FROM AUTHOR]