Sudan Savanna Research Articles

Effects of NPK fertilizer rates on the carbohydrate and crude protein contents of three varieties of potato (Solanum tuberosum L.) in Sudan Savanna of Nigeria

Field trials were conducted during the 2015/16 and 2016/17 dry seasons. The aim was to study the effects of NPK fertilizer rates on tuber carbohydrates and crude protein (CP) of three varieties of potato (Solanum tuberosum L.). The research was conducted at Teaching and Research Farm of Kebbi State University of Science and Technology, Aliero, located at Jega in the Sudan savanna zone of Nigeria. Treatments consist of four rates of NPK [20:10:10] fertilizer (0, 300, 600 and 900kg NPK ha-1) and three varieties (Bertita, Diamant and Nicola) of potato. Factorial combinations of fertilizer rates and varieties were laid out in a randomized complete block design, replicated three times. The size of each plot was 4.5 x 3 m (13.5m2). Results revealed that CP was affected by the dosage of fertilizer applied. 600 kg NPK ha-1 gave the highest CP above which there was no significant increase. Higher tuber carbohydrate content was recorded by Nicola and Bertita than Diamant; while crude protein was highest in Bertita compared to Nicola and Diamant. In this study, Bertita variety was higher in crude protein; and was comparable to Nicola, Bertita was lower (p ≤ 0.05) than Nicola and Diamant in carbohydrates. The use of 600 kg NPK ha-1 was optimum for good tuber quality.

Drivers of forage provision and erosion control in West African savannas—A macroecological perspective

Rangelands’ ability to provide ecosystem services (ESs) depends on ecosystem properties and functions, which are interactively driven by biophysical and land-use drivers. In West Africa’s savanna rangelands, the relative importance of these drivers for ES supply is still poorly understood, hampering the identification of appropriate management strategies. In this context, trade-offs between the ES of forage provision and the regulating ES of erosion control are of particular importance. Taking a macroecological perspective, we aimed at detecting consistent patterns in ES drivers and identifying good predictors. The study area comprises a steep gradient of climatic aridity across West Africa’s Sudanian savannas from northern Ghana to central Burkina Faso, in combination with local gradients of land-use intensity and topo-edaphic conditions. We used aboveground biomass, metabolisable energy and metabolisable energy yield as proxies for forage provision, and the cover of perennials in the grass layer as a proxy for erosion control. Linear mixed-effect models and model selection were used to test relationships between multiple environmental variables and ES proxies. We found differential responses of ES proxies to environmental drivers. Vegetation properties were important for all ESs. Antecedent rainfall was the most important predictor of aboveground biomass, while plants’ phenology and land-use were most important for metabolisable energy. Environmental variables (such as aridity, soil properties and grazing intensity) mediated via vegetation properties were the most important predictors of erosion control followed by the direct effect of climatic aridity. Our finding that antecedent rainfall was more important for forage provision than climatic aridity implies that the effects of long-term climatic aridity may in a given year be overridden by current season’s precipitation particularly in case of a good rain year. The observed importance of land-use and vegetation properties implies that well-conceived adaptation strategies could mitigate potential negative effects of climate change.

Effects of nitrogen levels and harvest ferquency on the growth and leaf quality of moringa (Moringa oleifera Lam) in Sudan Savanna of nigeria

Field experiment was conducted under irrigation at teaching and research farm of Faculty of Agriculture, Bayero University Kano, during 2011/2012 dry season to investigate the effects of different nitrogen levels and harvest frequency on growth and leaf quality of Moringa ( Moringa oleifera (Lam)). The treatments consisted of four levels of nitrogen (0, 50, 100 and 150 kg N ha -1 ) and three times of harvest frequency (2, 3, and 4 weeks). These were arranged in a split plot design with the nitrogen levels allocated to the main plots while the harvest frequency allocated to the sub plots and replicated four times. The data collected were subjected to analysis of variance (ANOVA) using GenStat and significant different means were separated using DMRT. The result shows that application of nitrogen significantly (P<0.05) increase plant height, number of leaflets plant -1 , plant stem diameter, number of branches plant -1 , fresh and dry weights plant -1 . Generally, the growth characters assessed gave maximum value with 150 kg N ha -1 treatment. At first harvest highest protein content of the leaf was also obtained with the higher Nitrogen level (150 kg N ha -1 ), highest Magnesium was obtained with 100 kg N ha -1 while highest quantity of phosphorus and potassium were obtained with 50 kg N ha -1 . The increase in harvest frequency significantly (P<0.05) increased dry leaf quality of Moringa with the highest protein quality obtained from 4 weeks harvest frequency. Nitrogen and harvest frequency interaction was found to be significant (P<0.05) on dry leaf quality of Moringa. Keywords: Moringa, nitrogen, harvest frequency and leaf quality

Designing neutral landscapes for data scarce regions in West Africa

Despite its popular adoption and use, neutral landscape models have been unexplored in data scarce areas of the Sudanian Savanna region where its application could serve as inputs for spatial ecosystem service assessment. Thus, the need for an easy to use tool to produce landscape patterns similar to real landscapes in this area is imminent. In this article, we aimed at introducing SG4GISCAME as a tool to meet this purpose by exploring it capabilities to generate landscapes similar to real agricultural landscapes of the Vea catchment area in Ghana in three steps. We used Voronoi tessellation polygons to develop the image patterns. The resulting artificial patterns were subsequently evaluated through a visual and landscape structural metric comparison between the simulated and real landscapes. Finally, we used a modified Turing Test to test the credibility of SG4GISCAME model output through expert pattern identification cues. The results show that SG4GISCAME can successfully generate agricultural landscape mosaics similar to real landscape under different parameters and user specifications. We attribute this to the tools’ intuitive and interactive user interface. Statistical test outcomes of the modified Turing Test suggested that geographic information systems and remote sensing map experts found marked pattern similarities between real and synthesis maps, resulting in challenges in identifying real maps from synthetic ones. Our approach could be replicated in other landscapes of West Africa to provide a substitute for unavailable or expensive spatial data and to test the hypothetical relationship between patchy landscape structure and ecosystem service provision through modelling.

Performance of cowpea (Vigna unguiculata (L.) Walp) under irrigation as influenced by weed management methods and intra row spacing

The study was conducted in the dry season of 2014/2015 at two locations: the experimental Farms of the Institute for Agricultural Research, Ahmadu Bello University Samaru, Zaria and Kadawa Kano, located in the Northern Guinea and Sudan Savanna Ecological Zones of Nigeria, to assess the effects of weed management methods and intra row spacing on performance of cowpea. The experiment was laid out in a split plot design with three replications. Treatments were five weed control methods involving the use of Pendimethalin at 1.0, 1.5 and 2.0 kg a.i. ha-1, two hoe weeding at 3 and 6 weeks after sowing (WAS) and a weedy check and four intra row spacing (20, 25, 30 and 35 cm). The herbicide treatments were assigned to the main plots while intra row spacings were assigned to the subplots.&nbsp; Results indicated that weed coverage score, weed density and weed dry weight were significantly decreased by the weed control methods compared to weedy check treatments. The application of Pendimethalin at the rate of 2.0 kg a.i ha-1 and two hoe weeding at 3 and 6 WAS resulted to significantly higher values for plant height, canopy spread and crop growth rate. Yield parameters including number pods per plant, seed weight and grain yield were also significantly increased in the herbicide treated plots and two hoe weeding compared to weedy check. In conclusion, the results obtained from this study indicated that two hoe weeding at 3 and 6 WAS and 20 cm intra row spacing effectively controlled weeds and produced the highest grain yield (kg ha-1) in Samaru, Zaria and Kadawa, Kano.

Evaporation from cultivated and semi-wild Sudanian Savanna in west Africa

Abstract. Rain-fed farming is the primary livelihood of semi-arid west Africa. Changes in land cover have the potential to affect precipitation, the critical resource for production. Turbulent flux measurements from two eddy-covariance towers and additional observations from a dense network of small, wireless meteorological stations combine to relate land cover (savanna forest and agriculture) to evaporation in a small (3.5 km2) catchment in Burkina Faso, west Africa. We observe larger sensible and latent heat fluxes over the savanna forest in the headwater area relative to the agricultural section of the watershed all year. Higher fluxes above the savanna forest are attributed to the greater number of exposed rocks and trees and the higher productivity of the forest compared to rain-fed, hand-farmed agricultural fields. Vegetation cover and soil moisture are found to be primary controls of the evaporative fraction. Satellite-derived vegetation index (NDVI) and soil moisture are determined to be good predictors of evaporative fraction, as indicators of the physical basis of evaporation. Our measurements provide an estimator that can be used to derive evaporative fraction when only NDVI is available. Such large-scale estimates of evaporative fraction from remotely sensed data are valuable where ground-based measurements are lacking, which is the case across the African continent and many other semi-arid areas. Evaporative fraction estimates can be combined, for example, with sensible heat from measurements of temperature variance, to provide an estimate of evaporation when only minimal meteorological measurements are available in remote regions of the world. These findings reinforce local cultural beliefs of the importance of forest fragments for climate regulation and may provide support to local decision makers and rural farmers in the maintenance of the forest areas.

Multiscale Remote Sensing to Map the Spatial Distribution and Extent of Cropland in the Sudanian Savanna of West Africa

Food security is the topmost priority on the global agenda. Accurate agricultural statistics (i.e., cropped area) are essential for decision making and developing appropriate programs to achieve food security. However, derivation of these essential agricultural statistics, especially in developing countries, is fraught with many challenges including financial, logistical and human capacity limitations. This study investigated the use of fractional cover approaches in mapping cropland area in the heterogeneous landscape of West Africa. Discrete cropland areas identified from multi-temporal Landsat data were upscaled to MODIS resolution using random forest regression. Producer’s accuracy and user’s accuracy of the cropland class in the Landsat scale analysis averaged 95% and 94%, respectively, indicating good separability between crop and non-crop land. Validation of the fractional cropland cover map at MODIS resolution (MODIS_FCM) revealed an overall mean absolute error of 19%. Comparison of MODIS_FCM with the MODIS land cover product (e.g., MODIS_LCP) demonstrate the suitability of the proposed approach to cropped area estimation in smallholder dominant heterogeneous landscapes over existing global solutions. Comparison with official government statistics (i.e., cropped area) revealed variable levels of agreement and partly enormous disagreements, which clearly indicate the need to integrate remote sensing approaches and ground based surveys conducted by agricultural ministries in improving cropped area estimation. The recent availability of a wide range of open access remote sensing data is expected to expedite this integration and contribute missing information urgently required for regional assessments of food security in West Africa and beyond.

Decomposition and Nitrogen Release Patterns of Parkiabiglobosa and Albizialebbeck Leaves with Nitrogen Fertilizer for Maize Production in Sudan Savanna Alfisolof Nigeria

Biomass transfer or cultivation of leguminous trees has higher eco-friendly profiles for soil nutrients restoration especially nitrogen. The research is conducted on decomposition and nitrogen release patterns of Parkia biglobosa and Albizia lebbeck leaves with nitrogen fertilizer for maize production in sudan savannah alfisol of Nigeria. Data were analysed using (ANOVA). 56 % of N in the litter bag was released the first two weeks of biomass incubation and progressively increases weeks after planting. Decomposition rate constant (KD) ranged from 9.18 to 15.07 week-1 and the rates of plant residues was higher in Albizia lebbeck than Parkia biglobosa in both seasons. Nitrogen release rate constant (KN), ranging from 7.82 to 10.81 week-1 followed a similar pattern as the rate of decomposition with Albizia lebbeck releasing the highest amount of N followed by Parkia lebbeck . The rate of decomposition increased as week increased. Incorporation of Albizia lebbeck had significantly higher effect (p < 0.05) on growth parameter and yield component compared to Parkia biglobosa . The study concluded that Albizia lebbeck decomposed and mineralized faster for crop uptake under sudan savanna conditions. The study suggests that incorporation of Albizia lebbeck and up to 40 kg N ha-1 is a better combination for soil quality improvement and maize productivity in Makera, a semi-arid environment of Nigeria.

Agronomic evaluation of cowpea cultivars developed for the West African Savannas

The goal of this research was to evaluate diverse cowpea genotypes developed over the past 4 decades in the Nigerian Sudan Savannas for their agronomic performance and to identify groups of cultivars with similar quantitative characters. Characterization would facilitate the efficient synthesis of breeding populations for further improvement of cowpea. Also superior genotypes with desirable characteristics could be identified and disseminated in the dry savannas of West Africa. Significant variations were observed in the agronomic characteristics of the cultivars in this study. Principal component analysis (PCA) and cluster analysis were performed on these genotypes and found that there were significant correlations among the variables measured. Modern cultivars outperformed the older ones and from the results of PCA, it was found that the most important variables for the classification of cowpea cultivars are high canopy, high seed weight, high total dry matter, high HI, and high grain and fodder yield. This suggests that these traits could be used in selection index for genetic improvement of cowpea. Cluster analysis resulted in 5 groups mostly corresponding to era of release except cluster I which contained cowpea cultivars from all eras. Two distinct groups in clusters IV and V were identified. Cultivars in cluster IV which were released in the 1990-2000 eras, had high grain and fodder yield. These cultivars could be evaluated on-farm for eventual release to farmers. They could also be used in breeding program for improvements in grain and fodder yield of cowpea. Cluster V contained two cultivars that distinctly had the highest fodder yield suggesting that they could be used to improve fodder yield of cowpea.

Drivers of farmers’ decisions to adopt agroforestry: Evidence from the Sudanian savanna zone, Burkina Faso

AbstractIn most developing countries, there has been a long-standing conflict of interest between using land for agriculture and the conservation of biodiversity. This paper reports on a study of factors influencing farmers’ decisions to integrate trees into their agricultural practice. We also discuss the possibility of protecting and managing planted and naturally regenerating trees on farmland in order to restore degraded land and improve biodiversity. Data were collected from interviews with farmers in the Center-West region of Burkina Faso and analyzed using Principal Component Analysis, multiple linear regression and binary logistic regression. The results show that farmers’ decisions to incorporate trees into their farmland were mainly influenced by silvicultural knowledge and skills, participation in farmers’ groups or other social organizations with an interest in tree conservation, the social value of biodiversity in the rural landscape, and the perceived economic benefits of trees on farmland. The most important factors associated with variation in levels of motivation to conserve trees on farms included household wealth, gender, age, education level, marital status, residence status, farmland size, household size and technical support. We conclude that an agroforestry project will be more successful if the local biophysical conditions and diversity of smallholder socio-economic characteristics and their perceptions, needs and preferences are considered in its design. There is also an immediate need for coordinated development of information and training to raise local community awareness of the potential of agroforestry as well as to disseminate information about adding value to tree products in order to encourage farmers to protect on-farm trees.

CERES-Maize Model for Determining the Optimum Planting Dates of Early Maturing Maize Varieties in Northern Nigeria.

Field trials were carried out in the Sudan Savannah of Nigeria to assess the usefulness of CERES–maize crop model as a decision support tool for optimizing maize production through manipulation of plant dates. The calibration experiments comprised of 20 maize varieties planted during the dry and rainy seasons of 2014 and 2015 at Bayero University Kano and Audu Bako College of Agriculture Dambatta. The trials for model evaluation were conducted in 16 different farmer fields across the Sudan (Bunkure and Garun—Mallam) and Northern Guinea (Tudun-Wada and Lere) Savannas using two of the calibrated varieties under four different sowing dates. The model accurately predicted grain yield, harvest index, and biomass of both varieties with low RMSE-values (below 5% of mean), high d-index (above 0.8), and high r-square (above 0.9) for the calibration trials. The time series data (tops weight, stem and leaf dry weights) were also predicted with high accuracy (% RMSEn above 70%, d-index above 0.88). Similar results were also observed for the evaluation trials, where all variables were simulated with high accuracies. Estimation efficiencies (EF)-values above 0.8 were observed for all the evaluation parameters. Seasonal and sensitivity analyses on Typic Plinthiustalfs and Plinthic Kanhaplustults in the Sudan and Northern Guinea Savannas were conducted. Results showed that planting extra early maize varieties in late July and early maize in mid-June leads to production of highest grain yields in the Sudan Savanna. In the Northern Guinea Savanna planting extra-early maize in mid-July and early maize in late July produced the highest grain yields. Delaying planting in both Agro-ecologies until mid-August leads to lower yields. Delaying planting to mid-August led to grain yield reduction of 39.2% for extra early maize and 74.4% for early maize in the Sudan Savanna. In the Northern Guinea Savanna however, delaying planting to mid-August resulted in yield reduction of 66.9 and 94.3% for extra-early and early maize, respectively.

Causes and Consequences of Increasing Herbicide Use in Mali

This paper examines the origins and impact of rapid recent growth of herbicide use in Mali. Primary data come from interviews with herbicide importers and distributors and from a 2014/2015 survey of farm households in Mali’s Sudanian Savanna zone. Results suggest that a series of major supply-side changes are driving growth in Mali’s herbicide markets, most conspicuously a proliferation in the number of sellers and herbicide brands marketed, a shift to low-cost suppliers in China and India, and consequently falling herbicide prices. At the farm level, herbicides cost on average 50 per cent less than hiring weeding labor. Despite low econometric estimates of damage abatement, herbicide adoption rates reach 25 per cent in remote rural zones and 75 per cent in more accessible rural areas. Key factors affecting adoption include spatial variation in herbicide prices and rural wage rates. At current levels, herbicide use reduces peak season rural labor demand by roughly 14 per cent.

Using CERES-Maize model to determine the nitrogen fertilization requirements of early maturing maize in the Sudan Savanna of Nigeria

ABSTRACTCERES-Maize model was used to determine nitrogen fertilizer requirements of early maturing maize varieties in the Sudan Savanna. Data were collected from 2013 to 2014 field experiments conducted in Bayero University Kano, (BUK), Kano, Nigeria. The experiments consisted of three nitrogen fertilizer levels (0, 60, and 120 kg N ha−1) and two early maize varieties (EVDT and 2009 TZEEW). Sensitivity analysis was performed to evaluate the responses of the two maizes to N fertilizers and for economic and strategic responses. The model predicted grain yield and harvest index reasonably well for the two varieties. Increasing N application from 0 to 30 kg N ha−1 increased grain yield by 105%, when nitrogen (N) rate was increased to 60 kg N ha−1, grain yield increased by 226%. Yield increases of 364%, 451%, and 461% was observed when N rate increased from 0 to 90, 120, and 150 kg ha−1, respectively.

Analysis of farmers’ adaptation to weather extremes in West African Sudan Savanna

Abstract There have been recent incidences of weather extremes in the West African Sudan Savanna and farmers have responded through implementation of relevant adaptation strategies. For a deeper insight into farmers’ adaptation to climatic shocks, this study documents farmers’ perception of recent changes in the local climate, and identifies factors that influence the number and choice of strategies implemented. Interdependencies among strategies are explored and joint and marginal probabilities of adoption estimated. Upper East Ghana and Southwest Burkina Faso are used as the case study regions. These regions were selected due to extreme reliance of inhabitants on agriculture for sustenance, and their recent exposure to weather extremes. Through estimation of a Poisson regression and multivariate probit model to identify the major factors that influence the number and choice of strategies adopted, we discover that, limited access to credit, markets, and extension services, smaller cropland area, and low level of mechanization could impede effective adaptation to weather extremes. To enhance farmers’ adaptive capacity, policy makers and various stakeholders need to contribute towards improving farmers’ access to credit, markets, and extension services, and implement measures to promote mechanization.

Contrasted effects of annual and perennial grasses on soil chemical and biological characteristics of a grazed Sudanian savanna

Growth and composition of plant communities depends on physico-chemical and biological characteristics of soils. Conversely, plants influence nutrient cycling and soil characteristics. Thus, they affect the long-term availability of nutrients, which feedbacks on their own growth and the primary productivity of ecosystems. This study focuses on the fertility and functioning of soils of a grazed savanna in Burkina Faso. It describes the effects of annual and perennial grasses involved in fallow succession, on chemical and biological (microbial biomass, mineralization and enzymatic activities) characteristics of soils. To do this, soil samples were collected under the four dominant species of grasses (A. ascinodis, A. gayanus, A. pseudapricus and L. togoensis) and under bare areas within 48 plots, as well as above- and belowground grass biomass. Results show that root biomass, pHKCl, basal respiration and fluorescein diacetate activities were significantly higher under perennial grasses (A. gayanus and A. ascinodis) than annual (A. pseudapricus and L. togoensis) and bare soil. Nitrate levels were higher under A. gayanus that had the lowest root biomass. Total carbon, total nitrogen, microbial biomass and acid phosphatase were higher under the perennial grass A. ascinodis. pHwater was lower under A. pseudapricus. Finally, ammonium and β-glucosidase activities weren’t significantly different between species. Overall, these results appear complex certainly due to factors of variability that remain to be identified. Nevertheless, they support the general hypothesis that perennial grasses have a greater influence on soil than annuals. Soil biological parameters (Basal respiration, microbial biomass, Beta-glucosidase, fluorescein-diacetate and acid phosphorus) exhibited strong relationship with soil pH, total C and N.

Effect of Sowing Methods, Seed Rate and Variety on Yield and Seed Quality of Sesame (Sesamum indicum L.) and Its Implication on Returns in Sudan Savanna of Nigeria

Effect of Sowing Methods, Seed Rate and Variety on Yield and Seed Quality of Sesame (Sesamum indicum L.) and Its Implication on Returns in Sudan Savanna of Nigeria

Tomato Fruits Yield and Soil Properties as Affected by Salts Application and Irrigation Schedule at Jega, Sudan Savanna Agro-ecological Zone

Tomato Fruits Yield and Soil Properties as Affected by Salts Application and Irrigation Schedule at Jega, Sudan Savanna Agro-ecological Zone

Pb Uptake in Roadside Grown Wheat (Triticum aestivum L.) in the Sudan Savanna, Kano State

Cereal crops grown under irrigation in a semi-arid ecological habitat can be used to assess food quality and safety of agricultural systems at proximity to highways in the Sudan savannah of Northern Nigeria. This study focussed on the risk assessments of Pb transfer, translocation and uptake at selected growth stages (15-, 30-, 45-, 60-, 75- and 90-days representing seedling or germination, tillering, shooting/booting, earing, flowering and ripening stages respectively of two cultivars of Triticum aestivum L. The experimental (SU 1) and control (SU 2) sites were selected based on distances (345 m and 1936 m) from the Kano-Zaria Highway. Pb levels in soils and the two cultivars of Triticum aestivum L. was measured using the double-beam AAS and plant uptake factors (PUF), soil-plant transfer coefficients (TC) and translocation factors (TF) were worked out. Result reveals differences in metal levels of the cultivars of wheat according to growth stages and plant parts. Pb levels was highly significant (P=0.05 and 0.01) in the stems of Siettecerros at the control site indicating selective ability of cultivar to Pb. Pb levels were highest in both cultivars at the 30-days growth stage indicating sensitivity of tillering stage to Pb uptake. A greater than unity value indicate anthropogenic source of Pb. Siettecerros had the highest TF indicating incorporation of higher levels of Pb in the edible plant parts. A higher PUF (45), TC (6.32) and TF (7.66) for Pb in Pavon-76 and Siettecerros respectively, indicates their suitability for bioremediation particularly, phytoextraction of polluted soils from atmospheric pollutants.

Spatio-Temporal Dynamics in Land Use and Habitat Fragmentation within a Protected Area Dedicated to Tourism in a Sudanian Savanna of West Africa

AbstractNazinga Game Ranch (NGR) is a reserve in Burkina Faso involving local communities for securing biodiversity through sustainable management. Yet, its ecosystems are threatened by increasing number of elephants and illegal human activities. Renowned as a model of wildlife participatory management, NGR has mainly been studied for its animal wildlife only. The aim of this study was to uncover ecological effects of recent land management on savanna habitats including tourism, and to conclude on more sustainable options, land use/land cover (LULC) changes and vegetation dynamics in NGR were analyzed. This was accomplished with multi-temporal change detection using Landsat images of 1984, 2002 and 2013 to map seven representative LULC classification categories, and quantitative indices of landscape metrics. The results showed that the LULC dynamics in NGR from 1984 to 2013 was mainly characterized by an expansion of gallery forest, tree savanna and agricultural area and a reduction of shrub savanna, woodland and bare soils. From 2002 to 2013, fragmentation in all land cover types increased at the landscape level, whereas at the class level, it decreased for woodland. Our findings provided evidence of habitat degradation in NGR, due to extensive agriculture, tourism and growing of elephants’ population. According to the original management goals and the purposes of the reserve, both fauna and tourism are to be maintained and sustained in a sustainable way. Adaptation of land use and targeted wildlife management are the main requirements for avoiding further degradation of vegetation and thus of the existence basis of local inhabitants, animals and tourism.

Vegetation Dynamics in the Upper Guinean Forest Region of West Africa from 2001 to 2015

The Upper Guinea Forest (UGF) region of West Africa is one of the most climatically marginal and human-impacted tropical forest regions in the world. Research on the patterns and drivers of vegetation change is critical for developing strategies to sustain ecosystem services in the region and to understand how climate and land use change will affect other tropical forests around the globe. We compared six spectral indices calculated from the 2001–2015 MODIS optical-infrared reflectance data with manually-interpreted measurements of woody vegetation cover from high resolution imagery. The tasseled cap wetness (TCW) index was found to have the strongest association with woody vegetation cover, whereas greenness indices, such as the enhanced vegetation index (EVI), had relatively weak associations with woody cover. Trends in woody vegetation cover measured with the TCW index were analyzed using Mann–Kendall statistics and were contrasted with trends in vegetation greenness measured with EVI. In the drier West Sudanian Savanna and Guinean Forest-Savanna Mosaic ecoregions, EVI trends were primarily positive, and TCW trends were primarily negative, suggesting that woody vegetation cover was decreasing, while herbaceous vegetation cover is increasing. In the wettest tropical forests in the Western Guinean Lowland Forest ecoregion, declining trends in both TCW and EVI were indicative of widespread forest degradation resulting from human activities. Across all ecoregions, declines in woody cover were less prevalent in protected areas where human activities were restricted. Multiple lines of evidence suggested that human land use and resource extraction, rather than climate trends or short-term climatic anomalies, were the predominant drivers of recent vegetation change in the UGF region of West Africa.