Papers by Elfatih M Abdel-Rahman
AGU Fall Meeting Abstracts, Dec 1, 2020
Authorea (Authorea), Mar 30, 2022
This a preprint and has not been peer reviewed. Data may be preliminary.
Environmental Monitoring and Assessment, Oct 18, 2022
Nature and Conservation, Nov 18, 2016
Habitat fragmentation is a threat to conservation of biodiversity hotspots in the Morogoro region... more Habitat fragmentation is a threat to conservation of biodiversity hotspots in the Morogoro region, Tanzania. However, ongoing research on fragmentation has not kept pace with temporal lapses and how individual species respond to habitat transformation and heterogeneity. This study sought to model spatial and temporal fragmentation patterns. Cloud free multi-temporal Landsat imagery with similar spectral resolution were acquired in the same season in 1975, 1995 and 2012. The images were used to characterize the biophysical landscape characteristics and a range of metrics used to quantify the magnitude of fragmentation. Patches and classes in the landscape were assessed using Fragstats, a spatial statistics program useful in computing landscape metrics. Results show that patch number was higher in dense forest and woodland than in less dense forest and grassland in 1975, 1995 and 2012 while the interspersion Juxtaposition Index (IJI) ranged between 0 (for clumped patches) and 100 (for grassland). In 1975 and 1995, the grassland habitat had the highest IJI while in 2012 less dense forest had the highest IJI. The Games-Howell test showed a significant fragmentation trend in less dense forests class (p≤0.05). Generally, the study indicates a high fragmentation pattern in the vulnerable tropical eastern arc mountain region of East Africa. This finding demonstrates the value of remotely sensed data in understanding the impact of anthropogenic processes on natural landscape transformation. Furthermore, the study provides a basis for informed conservation policy design and implementation in the region.
Gates Open Res, Oct 23, 2019
International Journal of Tropical Insect Science, Nov 13, 2020
Akin, M. B., Akin, M. S., and Kirmaci, Z. Effects of inulin and sugar levels on the viability of ... more Akin, M. B., Akin, M. S., and Kirmaci, Z. Effects of inulin and sugar levels on the viability of yogurt and probiotic bacteria and the physical and sensory characteristics in probiotic ice cream, Food Chemistry 104 (2007), pp. 93-99. Ares, G., and G´ambaro, A. Influence of gender, age and motives underlying food choice on perceived healthiness and willingness to try functional foods,
Environmental Entomology
Sustainable production of pumpkin (Cucurbita maxima Duchesne) partly relies on integrated pest ma... more Sustainable production of pumpkin (Cucurbita maxima Duchesne) partly relies on integrated pest management (IPM) and pollination services. A farmer-managed field study was carried out in Yatta and Masinga Sub-Counties of Machakos County, Kenya, to determine the effectiveness of a recommended IPM package and its interaction with stingless bee colonies (Hypotrigona sp.) for pollinator supplementation (PS). The IPM package comprised Lynfield traps with cuelure laced with the organophosphate malathion, sprays of Metarhizium anisopliae (Mechnikoff) Sorokin isolate ICIPE 69, the most widely used fungal biopesticide in sub-Saharan Africa, and protein baits incorporating spinosad. Four treatments—IPM, PS, integrated pest and pollinator management (which combined IPM and PS), and control—were replicated 4 times. The experiment was conducted in 600 m2 farms in 2 normalized difference vegetation index (NDVI) classes during 2 growing seasons (October 2019–March 2020 and March–July 2020). Fruits ...
Remote Sensing Letters, May 8, 2022
Isprs Journal of Photogrammetry and Remote Sensing, Nov 1, 2020
Anthropogenic activities and climate change have altered the environment profoundly, and Africa h... more Anthropogenic activities and climate change have altered the environment profoundly, and Africa has been more vulnerable due to lack of sustainable mitigation measures in place. The Intergovernmental Panel on Climate Change (IPCC) has reported that the most hazardous manifestation of climate change is through increased temperature, wetter and drier climates, heat waves and prolonged droughts, which in turn causes severe fluctuations in crop and animal production as well as biodiversity loss. Other impacts include land degradation, invasive species spread, pests and diseases proliferation, rangeland quality and quantity losses, among others. In coastal areas, agriculture is affected by inundation due to sea level rise as well as saltwater intrusion. The success of environmental management and protection lies in the availability of adequate information to support intervention measures by decision makers. Developments in remote sensing, particularly the recent remote sensors with high resolution (spatial, spectral and temporal) and freely available datasets creates a great opportunity for Africa to improve resources management and to stride towards achieving the UN sustainable Development Goals (SDG). In order to promote Earth observation research in Africa, a special issue call was made in 2019, dedicated to relevant scientific contributions that address environmental problems facing Africa using remote sensing. The call yielded a total of 13 publications, which are categorized into 5 themes: (1) Land cover/use change, (2) Hydrology and Drought, (3) Vegetation structure and alien invasive species, (4) Agriculture, and (5) Urban development. Within the land use change category, Thonfield et al. (2020) evaluated the impact of anthropogenic activities on protected areas (e.g., national park, game reserve, wildlife management area etc.) over a 40-year period. Results revealed significant impact of land use activities such as agriculture, human settlements and teak production on the Kilombero Ramsar site and other vegetation types (Thonfeld et al., 2020). A spatio-temporal hierarchical Bayesian model that forecasts ecological state under natural conditions was developed and tested in a fynbos of the Western Cape Floristic Region (Slingsby, Moncrieff, and Wilson 2020). The model, which was developed using landscape variables (climate, topography, soils and fire history) and could show the abrupt and gradual changes that occur within a system in near real time, demonstrated as an important tool for monitoring ecological changes. A study on shoreline retreat from 1952 to 2018 using aerial and orbital photogrammetric scenes revealed an abnormal rapid retreat (above the global average) in the Tunisian coastal areas, indicating the impact of urban growth and abrupt changes in precipitation patterns. The retreat has caused immense environmental damage, including soil desiccation, vegetation decline, and the proliferation of salt lakes (Amrouni, Hzami, and Heggy 2019). Three papers carried out water and drought related studies in semi
International journal of applied earth observation and geoinformation, Feb 1, 2010
Agronomy, Dec 6, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of Applied Remote Sensing, Dec 1, 2020
Abstract. Smallholder agroecological subzones (AEsZs) produce an array of crops occupying large a... more Abstract. Smallholder agroecological subzones (AEsZs) produce an array of crops occupying large areas throughout Africa but remain largely unmapped. We explored multisource satellite datasets to produce a seamless land-use and land-cover (LULC) and fragmentation dataset for upper midland (UM1 to UM4) AEsZs in central Kenya. Specifically, the utility of PlanetScope, Sentinel 2, and Landsat 8 images for mapping coffee-based landscape were tested using a random forest (RF) classifier. Vegetation indices, texture variables, and wavelength bands from all satellite data were used as inputs in generating four RF models. A LULC baseline map was produced that was further analyzed using FRAGSTAT to generate landscape metrics for each AEsZs. Wavelength bands model from Sentinel 2 had the highest overall accuracy with shortwave near-infrared and green bands as the most important variables. In UM1 and UM2, coffee was the dominant cover type, whereas annual and other perennial crops dominated the landscape in UM3 and UM4. The patch density for coffee was five times higher in UM4 than in UM1. Since Sentinel 2 is freely available, the approach used in our study can be adopted to support land-use planning in smallholder agroecosystems.
PLOS ONE, Jul 25, 2022
Using synthetic pesticides to manage pests can threaten pollination services, affecting the produ... more Using synthetic pesticides to manage pests can threaten pollination services, affecting the productivity of pollination-dependent crops such as avocado. The need to mitigate this negative externality has led to the emergence of the concept of integrated pest and pollinator management (IPPM) to achieve both pest and pollinator management, leading to complementary or synergistic benefits for yield and quality of the harvest. This paper aims to evaluate the potential economic and welfare impact of IPPM in avocado production systems in Kenya and Tanzania. We utilize both primary and secondary data and employed the economic surplus model. On average the potential economic gain from the adoption of IPPM is US$ 66 million annually in Kenya, with a benefit-cost ratio (BCR) of 13:1, while in Tanzania US$ 1.4 million per year, with a BCR of 34:1. The potential benefits from IPPM intervention gains are expected to reduce the number of poor people in Kenya and Tanzania by 10,464 and 1,255 people per year respectively. The findings conclude that policies that enhance the adoption of IPPM can fast-track economic development and therefore improve the livelihoods of various actors across the avocado value chain.
Geocarto International, May 20, 2015
ABSTRACT Estimating tropical biomass is critical for establishment of conservation inventories an... more ABSTRACT Estimating tropical biomass is critical for establishment of conservation inventories and landscape monitoring. However, monitoring biomass in a complex and dynamic environment using traditional methods is challenging. Recently, biomass estimates based on remotely sensed data and ecological variables have shown great potential. The present study explored the utility of remotely sensed data and topo-edaphic factors to improve biomass estimation in the Eastern Arc Mountains of Tanzania. Twenty nine vegetation indices were calculated from RapidEye data, while topo-edaphic factors were taken from field measurements. Results showed that using topo-edaphic variables or vegetation indices, biomass could be predicted with an R2 of 0.4. A combination of topo-edaphic variables and vegetation indices improved the prediction accuracy to an R2 of 0.6. Results further showed a decrease in biomass estimates from 1162 ton ha−1 in 1980 to 285.38 ton ha−1 in 2012. This study demonstrates the value of combining remotely sensed data with topo-edaphic variables in biomass estimation.
South Africa is the leading producer of sugarcane in Africa and one of the largest sugarcane prod... more South Africa is the leading producer of sugarcane in Africa and one of the largest sugarcane producers in the world. Sugarcane is grown under a wide range of climatic, agronomic, and socioeconomic conditions in the country. Stress factors such as water and nutrient deficiencies, and insect pests and diseases are among the most important factors affecting sugarcane production in the country. Monitoring of stress in sugarcane is First and foremost I thank Allah for giving me health, power and support, and for making it possible for me to complete my PhD thesis. My research project was undertaken in conjunction between the University of KwaZulu-Natal (UKZN), the South African Sugarcane Research Institute (SASRI) and the University of Khartoum (U of K). I would like to thank these institutions for giving me the opportunity to read for a PhD. Their financial support for living allowance, field work, satellite imageries, and laboratory analyses was also appreciated. I thank my supervisors Prof. Fethi B. Ahmed (UKZN) and Dr. Maurits van den Berg (SASRI) for their committed guidance and assistance during the course of this study. You taught me how to be a researcher, I learnt how to critically and scientifically comment on and review research work. I also would like to thank my research project members from
Isprs Journal of Photogrammetry and Remote Sensing, 2020
Invasive plant species in eastern Africa severely impede rangeland and cropland productivity with... more Invasive plant species in eastern Africa severely impede rangeland and cropland productivity with dire consequences for livelihoods of agro-pastoralist communities. We produced the first occurrence and spread map of invasive plant species (Prosopis: Prosopis juliflora and Parthenium: Parthenium hysterophorus) for western Somaliland (a region of eastern Africa) using vegetation productivity and phenology trends from 250 m MODIS (Moderate Resolution Imaging Spectroradiometer) EVI (Enhanced Vegetation Index) time-series data (2001-2014). Binomial logistic regression models were created to predict the presence or absence of the invasive species from the MODIS EVI phenometrics and vegetation productivity trends. Model training pixels were extracted from a 30 m Landsat-based classification that mapped areas of propagation of the two invasive species between 2001 and 2015. Field observations collected during 2014 and 2015 were used as reference data for the Landsat classification. After optimization of the logistic regression models, a probability of occurrence map was produced and evaluated for each of the two invasive species. The probability maps predicted that the croplanddominated areas in the southwestern part of Somaliland were considerably infested with Parthenium while Prosopis was most abundant in the peri-urban zones and the central and eastern regions. Vegetation amplitude (the seasonal cycle of vegetation between the vegetation peak and the trough) was most relevant and statistically significant for predicting the spread of Parthenium. This highlights the importance of vegetation seasonality variables for the wide-area mapping of herbaceous life forms in semi-arid biomes. Mann-Kendall trends based on annual summed EVI value and seasonal EVI peak value trends were the most relevant predictors for the occurrence of Prosopis. Phenometric trends show immense potential to map shifts in vegetation patterns in relation to the spread of invasive species as a consequence of global change effects, particularly in African drylands.
Earth
In the recent past, the Horn of Africa witnessed an upsurge in the desert locust (Schistocerca gr... more In the recent past, the Horn of Africa witnessed an upsurge in the desert locust (Schistocerca gregaria) invasion. This has raised major concerns over the massive food insecurity, socioeconomic impacts, and livelihood losses caused by these recurring invasions. This study determined the potential vegetation damage due to desert locusts (DLs) and predicted the suitable habitat at high risk of invasion by the DLs using current and future climate change scenarios in Kenya. The normalized difference vegetation index (NDVI) for the period 2018–2020 was computed using multi-date Sentinel-2 imagery in the Google Earth Engine platform. This was performed to assess the vegetation changes that occurred between May and July of the year 2020 when northern Kenya was the hotspot of the DL upsurge. The maximum entropy (MaxEnt) algorithm was used together with 646 DL occurrence records and six bioclimatic variables to predict DL habitat suitability. The current (2020) and two future climatic scenar...
PLOS ONE
Mapping of land use/ land cover (LULC) dynamics has gained significant attention in the past deca... more Mapping of land use/ land cover (LULC) dynamics has gained significant attention in the past decades. This is due to the role played by LULC change in assessing climate, various ecosystem functions, natural resource activities and livelihoods in general. In Gedaref landscape of Eastern Sudan, there is limited or no knowledge of LULC structure and size, degree of change, transition, intensity and future outlook. Therefore, the aims of the current study were to (1) evaluate LULC changes in the Gedaref state, Sudan for the past thirty years (1988–2018) using Landsat imageries and the random forest classifier, (2) determine the underlying dynamics that caused the changes in the landscape structure using intensity analysis, and (3) predict future LULC outlook for the years 2028 and 2048 using cellular automata-artificial neural network (CA-ANN). The results exhibited drastic LULC dynamics driven mainly by cropland and settlement expansions, which increased by 13.92% and 319.61%, respecti...
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Papers by Elfatih M Abdel-Rahman