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

Socio-Ecological Niche and Factors Affecting Agroforestry Practice Adoption in Different Agroecologies of Southern Tigray, Ethiopia

This study was carried out in the southern zone of Tigray to identify and characterize traditional common agroforestry practices and understand the existing knowledge of farm households on the management of trees under different agroforestry in different agroecologies. We conducted reconnaissance and diagnostic surveys by systematically and randomly selecting 147 farming households in the three agroecologies of the study area. A logit regression model was employed to determine how these factors influence farmers&rsquo; adoption decision. The findings indicate that a majority of the households (46.3%) were engaged in homestead agroforestry practices (AFP), followed by live fence (25.9%) and farmland or parkland (15%) agroforestry practices. The study identified Carica papaya, Malus domestic, Persea americana, Mangifera indica, Ziziphus spina-christi, and Balanites aegyptiaca as the most dominant fruit tree species found in the home garden agroforestry. In total, 68% of the households had some of these fruit trees around their home gardens. We also established the three most dominant agricultural production systems as: i) Agricultural production system, composed of fruit tree + cereal crops + Ziziphus spina-christi + Balanites aegyptiaca and/or acacia species; ii) agricultural production system, consisting of cash crops, like Coffee arabica and Catha edulies + fruit trees + Cordia africana + Balanites aegyptiaca and/or acacia species; and iii) agricultural production, composed of fruit trees + vegetables within a boundary of Sesbania sesban and other acacia species in the modern irrigated land. Furthermore, 90.16% of the households in the highlands reported a shortage of farmland for planting trees as the main constraint. About 34.44% farmers reported using leaves of Cordia africana, Balanites aegyptiaca, pods of acacia species, and crop residue as the main source of animal fodder. In total, 86.4% of the households also recognized the importance of multipurpose trees for soil fertility enhancement, control of runoff, microclimate amelioration, environmental protection, and dry season animal fodder. According to the logit model analysis, sex, family size, educational level, and landholding significantly (p &lt; 0.05) influence the household&rsquo;s role in the adoption of agroforestry practices. Based on these findings, farmers used different adaptation strategies, such as planting of multi-purpose trees (34.7%), conservation tillage to minimize both erosion and runoff potentials as soil conservation strategies (27.2%), varying planting dates, use of drought tolerant crop varieties (16.3%), and others based on farmers&rsquo; indigenous knowledge passed down from generation to generation. We conclude that agroforestry practices are important components of farming systems in Tigray, resulting in diversified products and ecological benefits that improve socio-ecological resilience. Therefore, we recommend that agroforestry practices are mainstreamed into development plans, especially in agriculture

The Effect of the war on smallholder agriculture in Tigray, Northern Ethiopia

AbstractThe war in Tigray (Northern Ethiopia) that started at the beginning of November 2020 has brought devastating damage to smallholder agriculture and food security. However, empirical evidence on the effect of war on smallholder agriculture has not studied systematically. Thus, this research was initiated to address the knowledge gap. A survey was done on selected 4376 households using systematic random sampling. All the data required for the study was collected using a semi-structured questionnaire, focus group discussions and key informant interview. The study revealed that 81% of the smallholder households lost their crop followed by livestock (75%) and farm tools (48%). Overall, 94% of the households reported that at least one of their agricultural components (crop, livestock and farm tools) was looted and/or destroyed by the belligerents. Of which, 37% of the respondent’s crop, livestock and farm tools were totally damaged. Moreover, farmers have limited access to their farms, agricultural inputs, and services. Consequently, more than 5.2 million people are currently in need of immediate humanitarian assistance. To avert the worsening situation, immediate intervention is needed to deliver food and agricultural input supplies and rehabilitate the agricultural extension system and infrastructure

Impact of climate variability and environmental policies on vegetation dynamics in the semi-arid Tigray

Abstract Anthropogenic and climate-related phenomena are among the main factors responsible for variations in vegetation structure and composition worldwide. However, studies that integrate the effects of human activities and climate variability in fragile tropical ecosystems, including the semi-arid Tigray region, are lacking. The objective of this study was to examine the effects of climate variability and environmental policy changes on the spatial distribution and pattern of vegetation cover in the semi-arid Tigray region of Ethiopia over the past four decades. We used satellite-based vegetation index (normalized difference vegetation index) and monthly rainfall data to analyze the relationship between vegetation cover and climatic variability. Residual analysis was also used to further disentangle the effects of climatic variability and environmental policy on vegetation cover. The regression analysis (r2 = 0.19) showed an insignificant causal relationship between vegetation dynamics and precipitation over the 41-years study period. This study also highlighted negative impact of the global rise in temperature on vegetation cover due to water stress caused by evapotranspiration. On the other hand, the residual analysis results (r = − 0.55, z-stat = − 11.58, p < 0.01) indicated a strong relationship between vegetation change and environmental policies implemented within the specified study period. Overall, the study revealed that environmental policies had a greater impact than climate variables on vegetation. Policymakers should, therefore, prioritize implementing effective environmental policies to restore degraded ecosystems and mitigate the effects of climate change

Landscape pattern and climate dynamics effects on ecohydrology and implications for runoff management: case of a dry Afromontane forest in northern Ethiopia

In this study, we assessed the land use land cover dynamics, rainfall trends, spatio-temporal runoff potentials, and proposed runoff management options in a dry Afromontane forest in northern Ethiopia. Satellite images (1986, 2001 and 2018) were classified using the maximum likelihood method, and responses to runoff were determined using a hydrologic model. A trend-free pre-whitening Mann–Kendall (TFPW-MK) test was used to analyze the areal weighted rainfall trends. The forest and shrubland coverage expanded (451 and 421 ha/year) between 1986 and 2001; however, the forest land showed lower rate of increment (248 ha/year) during 2001–2018 due to anthropogenic influences. The shift of bimodal rainy seasons to a monomodal with high runoff volume was experienced in 2001–2018. The TFPW-MK test revealed that the rainfall trend was statistically insignificant, but showed a decreasing pattern. In general, ecological restoration can be achieved via implementing the proposed conservation measures like percolation pond, storage tank, check dams, contour bunds, terraces, trenches, area closure and combination of these measures

Land Use and Land Cover Change Detection and Prediction in the Kathmandu District of Nepal Using Remote Sensing and GIS

Understanding land use and land cover changes has become a necessity in managing and monitoring natural resources and development especially urban planning. Remote sensing and geographical information systems are proven tools for assessing land use and land cover changes that help planners to advance sustainability. Our study used remote sensing and geographical information system to detect and predict land use and land cover changes in one of the world&rsquo;s most vulnerable and rapidly growing city of Kathmandu in Nepal. We found that over a period of 20 years (from 1990 to 2010), the Kathmandu district has lost 9.28% of its forests, 9.80% of its agricultural land and 77% of its water bodies. Significant amounts of these losses have been absorbed by the expanding urbanized areas, which has gained 52.47% of land. Predictions of land use and land cover change trends for 2030 show worsening trends with forest, agriculture and water bodies to decrease by an additional 14.43%, 16.67% and 25.83%, respectively. The highest gain in 2030 is predicted for urbanized areas at 18.55%. Rapid urbanization&mdash;coupled with lack of proper planning and high rural-urban migration&mdash;is the key driver of these changes. These changes are associated with loss of ecosystem services which will negatively impact human wellbeing in the city. We recommend city planners to mainstream ecosystem-based adaptation and mitigation into urban plans supported by strong policy and funds

Integrating Satellite Rainfall Estimates with Hydrological Water Balance Model: Rainfall-Runoff Modeling in Awash River Basin, Ethiopia

Hydrologic models play an indispensable role in managing the scarce water resources of a region, and in developing countries, the availability and distribution of data are challenging. This research aimed to integrate and compare the satellite rainfall products, namely, Tropical Rainfall Measuring Mission (TRMM 3B43v7) and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record (PERSIANN-CDR), with a GR2M hydrological water balance model over a diversified terrain of the Awash River Basin in Ethiopia. Nash–Sutcliffe efficiency (NSE), percent bias (PBIAS), coefficient of determination (R2), and root mean square error (RMSE) and Pearson correlation coefficient (PCC) were used to evaluate the satellite rainfall products and hydrologic model performances of the basin. The satellite rainfall estimations of both products showed a higher PCC (above 0.86) with areal observed rainfall in the Uplands, the Western highlands, and the Lower sub-basins. However, it was weakly associated in the Upper valley and the Eastern catchments of the basin ranging from 0.45 to 0.65. The findings of the assimilated satellite rainfall products with the GR2M model exhibited that 80% of the calibrated and 60% of the validated watersheds in a basin had lower magnitude of PBIAS (&lt;±10), which resulted in better accuracy in flow simulation. The poor performance with higher PBIAS (≥±25) of the GR2M model was observed only in the Melka Kuntire (TRMM 3B43v7 and PERSIANN-CDR), Mojo (PERSIANN-CDR), Metehara (in all rainfall data sets), and Kessem (TRMM 3B43v7) watersheds. Therefore, integrating these satellite rainfall data, particularly in the data-scarce basin, with hydrological data, generally appeared to be useful. However, validation with the ground observed data is required for effective water resources planning and management in a basin. Furthermore, it is recommended to make bias corrections for watersheds with poorlyww performing satellite rainfall products of higher PBIAS before assimilating with the hydrologic model