Hydrological response of dry Afromontane forest to changes in land use and land cover in northern Ethiopia

This study analyzes the impact of land use/land cover (LULC) changes on the hydrology of the dry Afromontane forest landscape in northern Ethiopia. Landsat satellite images of thematic mapper (TM) (1986), TM (2001), and Operational Land Imager (OLI) (2018) were employed to assess LULC. All of the images were classified while using the maximum likelihood image classification technique, and the changes were assessed by post-classification comparison. Seven LULC classes were defined with an overall accuracy 83-90% and a Kappa coefficient of 0.82-0.92. The classification result for 1986 revealed dominance of shrublands (48.5%), followed by cultivated land (42%). Between 1986 and 2018, cultivated land became the dominant (39.6%) LULC type, accompanied by a decrease in shrubland to 32.2%, as well as increases in forestland (from 4.8% to 21.4%) and bare land (from 0% to 0.96%). The soil conservation systems curve number model (SCS-CN) was consequently employed to simulate forest hydrological response to climatic variations and land-cover changes during three selected years. The observed changes in direct surface runoff, the runoff coefficient, and storage capacity of the soil were partially linked to the changes in LULC that were associated with expanding bare land and built-up areas. This change in land use aggravates the runoff potential of the study area by 31.6 mm per year on average. Runoff coefficients ranged from 25.3% to 47.2% with varied storm rainfall intensities of 26.1-45.4 mm/ha. The temporal variability of climate change and potential evapotranspiration increased by 1% during 1981-2018. The observed rainfall and modelled runoff showed a strong positive correlation (R-2 = 0.78; p < 0.001). Regression analysis between runoff and rainfall intensity indicates their high and significant correlation (R-2 = 0.89; p < 0.0001). Changes were also common along the slope gradient and agro-ecological zones at varying proportions. The observed changes in land degradation and surface runoff are highly linked to the change in LULC. Further study is suggested on climate scenario-based modeling of hydrological processes that are related to land use changes to understand the hydrological variability of the dry Afromontane forest ecosystems

Trade-offs in multi-purpose land use under land degradation

CITATION: Vlek, P. L. G., et al. 2017. Trade-offs in multi-purpose land use under land degradation. Sustainability, 9(12):2196, doi:10.3390/su9122196.The original publication is available at http://www.mdpi.com/journal/sustainabilityAbstract: Land provides a host of ecosystem services, of which the provisioning services are often considered paramount. As the demand for agricultural products multiplies, other ecosystem services are being degraded or lost entirely. Finding a sustainable trade-off between food production and one or more of other ecosystem services, given the variety of stakeholders, is a matter of optimizing land use in a dynamic and complex socio-ecological system. Land degradation reduces our options to meet both food demands and environmental needs. In order to illustrate this trade-off dilemma, four representative services, carbon sinks, water storage, biodiversity, and space for urbanization, are discussed here based on a review of contemporary literature that cuts across the domain of ecosystem services that are provided by land. Agricultural research will have to expand its focus from the field to the landscape level and in the process examine the cost of production that internalizes environmental costs. In some situations, the public cost of agriculture in marginal environments outweighs the private gains, even with the best technologies in place. Land use and city planners will increasingly have to address the cost of occupying productive agricultural land or the conversion of natural habitats. Landscape designs and urban planning should aim for the preservation of agricultural land and the integrated management of land resources by closing water and nutrient cycles, and by restoring biodiversity.https://www.mdpi.com/2071-1050/9/12/2196Publisher's versio

CDM afforestation for managing water, energy and rural income nexus in irrigated drylands

Rural livelihood in arid irrigated areas is hampered by water scarcity, land degradation and climate change. Studies showed a possibility to tackle these challenges by establishing tree plantations on marginal croplands as supported by the Clean Development Mechanism (CDM) forestation programs. Despite the environmental impact such projects would also affect the decision making of rural population by changing their land use activities, incomes and consumption structures. Thus, this study further analyzed the impact of CDM forestation on rural livelihood by considering rural interdependencies via wage-labor relations of agribusiness-operated farms and rural households in the Khorezm province and southern districts of Autonomous Republic of Karakalpakstan, Uzbekistan. We developed a farm-household dynamic programming model that jointly maximizes farm profits and rural households net incomes over a 15-years horizon under the scenario of decreasing irrigation water availability and plantation forestry with a seven year rotation period. The analysis showed that shortly following a land use change towards afforestation, the farm demand for rural households’ labor would decline thus decreasing the household incomes. Yet, later on after harvesting tree plantations, in year seven, the farm benefits would be transmitted to rural households via access to cheaper fuelwood and leaves as fodder, as well as via improved land use activities. The availability of fuelwood from tree plantations would significantly decrease CO2 emissions of households by substituting fossil fuels, while leaves would reduce expenditures for livestock fodder. These substitution effects would lead to the increase of income and in turn improve households’ food consumption. Besides, given the low irrigation demand of trees, a conversion of marginal cropland to tree plantations would increase the irrigation water availability for other productive croplands. These changes would lead that tree plantations would increase in year seven profits of farmer (up to 39,200 USD) and net incomes of rural households (up to 12,700 USD). Whereas when only conventional land uses are followed the decline in water availability would reduce profits of farm (from 13,000 USD to 9,850 USD) and net incomes of rural households (from 11,900 to 10,500 USD) over the modeled period. Overall, we argue that the implementation of the short-term CDM forestation could help cushion repercussions of water shortages on rural livelihoods, sustaining energy, income and food security, as well as mitigating climate change in drylands

Year-Round Irrigation Schedule for a Tomato–Maize Rotation System in Reservoir-Based Irrigation Schemes in Ghana

Improving irrigation management in semi-arid regions of Sub-Saharan Africa is crucial to respond to increasing variability in rainfall and overcome deficits in current irrigation schemes. In small-scale and medium-scale reservoir-based irrigation schemes in the Upper East region of Ghana, we explored options for improving the traditional, dry season irrigation practices and assessed the potential for supplemental irrigation in the rainy season. The AquaCrop model was used to (i) assess current water management in the typical tomato-maize rotational system; (ii) develop an improved irrigation schedule for dry season cultivation of tomato; and (iii) determine the requirement for supplemental irrigation of maize in the rainy season under different climate scenarios. The improved irrigation schedule for dry season tomato cultivation would result in a water saving of 130&ndash;1325 mm compared to traditional irrigation practices, accompanied by approximately a 4&ndash;14% increase in tomato yield. The supplemental irrigation of maize would require 107&ndash;126 mm of water in periods of low rainfall and frequent dry spells, and 88&ndash;105 mm in periods of high rainfall and rare dry spells. Therefore, year-round irrigated crop production may be feasible, using water saved during dry season tomato cultivation for supplemental irrigation of maize in the rainy season

Physiological and Shoot Growth Responses of <i>Abies holophylla</i> and <i>Abies koreana</i> Seedlings to Open-Field Experimental Warming and Increased Precipitation

Projected changes in temperature and precipitation in mid-latitude wet regions are expected to significantly affect forest ecosystems. We studied the physiological and shoot growth responses of Abies holophylla and Abies koreana seedlings to warming (3 °C above ambient temperature) and increased precipitation (irrigation with 40% of rainfall) treatments under open-field conditions. The physiological parameters, quantified by the net photosynthetic rate, transpiration rate, stomatal conductance, and total chlorophyll content, were monitored from July to October 2018. Shoot growth (i.e., root collar diameter and height) was assessed in August and December 2018. Irrespective of the treatments, the physiological parameters of both species decreased from July to August under warming treatment due to heat stress before recovering in September and October. Warming alone (W) and warming along with increased precipitation (W*P) decreased the physiological activities of both species in July, August, and September, with more pronounced effects on A. koreana compared with A. holophylla. Increased precipitation resulted in the increased chlorophyll content of both species in October. Shoot growth was not generally affected by the treatments, except for a subtle reduction in height under W*P for A. koreana. A. holophylla had consistently higher values for the physiological parameters and shoot growth than A. koreana. Our results indicate that the physiological activities of the Abies species could be seriously reduced under climate change, with a more severe impact on A. koreana. Among the two species, A. holophylla appears to be a more robust candidate for future forest planting

Inaugural editorial

This inaugural editorial introduces the research topics addressed by the journal Change and Adaptation in Socio-Ecological Systems (CASES). A recent literature analysis revealed that the amount of integrative, interand transdisciplinary research activities on climate and global change, adaptive strategies, actor behaviors and response opportunities has increased significantly in the last few decades. Also, research activities on major drivers for the change and adaptation of socio-ecological systems, namely climate change, socio-economic and political changes and technological development have increased considerably since the 1950s. A publication platform that allows for overarching perspectives, integrative viewpoints, and the exchange of ideas among related disciplines in Socio-Ecological Systems (SES) science is provided by the new journal CASES

Economic analysis of afforestation of marginal croplands in Uzbekistan

Irrigated agricultural production in Uzbekistan is threatened by the impacts of land degradation, irrigation water scarcity and climate change. The conversion of marginal croplands to tree plantations is an option for rehabilitation of nutrient-depleted cropland soils, saving of irrigation water, carbon sequestration, and improving population welfare. The economic benefits and impacts of tree planting on marginal croplands, and policies that may facilitate the adoption of this land use are not well known. We employed various methods at different scales to investigate economically viable options of afforestation on marginal croplands on example of irrigated drylands of Uzbekistan. This includes analyzing the impacts of afforestation supported by the carbon (C) sequestration reward on the rural livelihoods. At field level (one hectare), the stochastic dominance analysis was employed to investigate the financial attractiveness of afforestation on marginal farmlands under uncertainty. At the farm level, the expected utility method was employed to analyze effects of this land use change on farm incomes. To consider the bimodal structure of agriculture in Uzbekistan, the stochastic dynamic farm-household model was developed. The results indicate that due to benefits from non-timber products, afforestation is a more viable land use option on marginal lands than crop cultivation. Allowing the exemption of marginal lands from cotton cropping in favor of tree planting would incentivize afforestation. At the same time, the field level analysis indicates that due to variability in returns a substantial increase in C prices would make afforestation as financially attractive as crops on marginal lands. However, when considering uncertainties in land use returns at the whole farm level, afforestation would occur without the C incentives due to improved irrigation water use efficiency and reduced revenue risks through land use diversification. Through the considered farm-household wage-labor relationship, the benefits of afforestation on marginal croplands at farm would be also transferred to rural smallholders employed at this farm. This would mainly result from improved payment structure by tree products, particularly fuelwood and foliage for livestock fodder