The focus of the West African Journal of Applied Ecology is on ecology, agriculture and water pollution.

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The Globethics.net library contains articles of the West African Journal of Applied Ecology as of vol. 1(2000) to current.

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  • Cadmium Tolerance and Phytoremediation Strategies of Selected Tropical plants Cultivated on Industrial Dump Site under the Influences of Two Mycobionts

    Dada, O. E. (Ecological Laboratory Unit, University of Ghana, 2020-01-23)
    This research was carried out on a waste disposal site of a paint industry in Ijebu- Ijesha, Osun State, Nigeria in an attempt to assess the cadmium toxicity tolerance and bioremediation strategies of selected tropical plants cultivated under the influence of two mycobionts. On the waste disposal site, two plots (Plot A and B) having size of about 9 m by 12 m each were prepared with a control plot (Plot C) which is a non-polluted site. The experimental design on the first plots (Plot A) was 4x2x3 in which viable seeds of the four selected weeds were grown and inoculated with two mycobionts (Glomus intraradices and Glomus mosseae) respectively in a randomized complete block design with three replicates. However, on the second (Plot B) and control plots, only the seeds of the weeds were grown without mycorrhiza treatment using the same experimental design of 4x3 respectively. After Twelve weeks of planting, each plant was harvested, separated into root and shoot tissues and analysed for Cd concentrations using Atomic Absorption Spectrophotometry (AAS). Data collected were subjected to descriptive and inferential statistics. The highest (18.51 mg/kg) concentrations of Cd were reported in Amaranthus spinosus with root and shoot bioconcentration factors; and transfer factors greater than 1.00. Out of the four plants, 75% act as cadmium phytostabilizers in the absence of inocula and were good candidates for the biomanagement of hazardous sites while all the plant displayed the characteristics of a cadmium phytoextractor under mycorrhizal inoculation with Amaranthus spinosus having the highest mobility indices of cadmium under the influence of Glomus intraradices. The study concluded that the four weeds are good Cd phytoextractors in the remediation and biomanagement of marginal lands under bioaugmentation.
  • Investigation of the factors that contribute to degradation of Songor Ramsar and UNESCO Man and Biosphere Reserve in Ghana

    Fianko, J. R.; Dodd, H. S. (Ecological Laboratory Unit, University of Ghana, 2020-01-23)
    This study on the Songor Ramsar and UNESCO Man and Biosphere Reserve in Ghana seeks to investigate the factors that contribute to degradation of Songor Ramsar and UNESCO Man and Biosphere Reserve in Ghana through the administration of structured questionnaires using the drop-and–collect approach, face-to-face interviews and focus group discussions. The study revealed that the ranking of natural resources and occupation of the area are based on the demarcated zones within which the community is situated. Salt, fisheries and arable lands were identified as the most important natural resource in the wetland. The results on environmental degradation of the wetlands in the Songor Ramsar site in Ghana made it clear that the underlying causes of environmental degradation in the Songor Ramsar site are mainly a combination of Institutional and policy failures. It was revealed that the problem of environmental degradation is a consequence of ineffective enforcement of bye-laws. A combination of several factors such as improper waste disposal, poor attitude of residents toward environmental conservation, wildfires and shoreline recession, inadequate public education on the impact of environmental degradation, fishing and farming activities were identified during the administration of structured questionnaire, face-to-face interviews and focus group discussions. The other factors include overgrazing, over exploitation of mangroves, Predation, poaching and over fishing, uncontrolled sand and salt winning. Constraints and weaknesses to the implementation of regulations and laws with respect to conservation and protection of the wetlands identified during the study are lack of public education on the economic importance and the need to conserve the wetland, encroachment by developers, lack of enforcement of bye-laws, over-exploitation of mangroves and waste management.
  • Degradation of total petroleum hydrocarbon in petroleum products-contaminated soil using pig dung

    Bada, B. S.; Egbeja, T. I.; Arowolo, T. A.; Obuotor, T. M. (Ecological Laboratory Unit, University of Ghana, 2020-01-23)
    This study determined the effect of pig dung on the degradation of total petroleum hydrocarbon in petroleum products-contaminated soil. Topsoil (0-15 cm depth) was collected from Teaching and Research Farm, Federal University of Agriculture Abeokuta, Nigeria. One kilogram of the soil was measured into nine containers and contaminated with a 10 % mixture of gasoline and diesel. Pig Dung (PD) was mixed with the soil at the rate of 0, 50 and 100 g kg-1 soil in triplicate and the containers were arranged in a Completely Randomized Design. Soil samples were taken from each container at 21 and 42 days for Hydrocarbon Utilizing Bacteria (HUB) and Total Petroleum Hydrocarbon (TPH) determination using standard methods. Collected data were subjected to descriptive and inferential statistics. The HUB species identified were Bacillus, Staphylococcus, Escherichia, and Klebsiella. The TPH (mg kg-1) of the soil before the PD application was 83.55±0.22. After the amendments (at 0, 50 and 100 g kg-1), values were 63.24±0.25, 50.09±0.64, 39.56±0.15 and 49.72±1.30, 34.51±0.56, 16.89±0.36 for 21 and 42 days respectively. Pig dung enhanced degradation of total petroleum hydrocarbon in the petroleum products-contaminated soil.
  • Species-Packing of Grazers in the Mole National Park, Ghana

    Dakwa,, K. B. (Ecological Laboratory Unit, University of Ghana, 2020-01-23)
    Hutchinson’s body weight ratio (WR) theory was used to determine the degree of species-packing of 22 species of grazers in Mole National Park (MNP). The hypotheses, which suggest that facilitation is more likely to occur at a WR greater than 2.0, competition at WR less than 2.0, and coexistence at WR equals 2.0 were tested by regressing the natural logarithm of the body mass of a grazer against its rank number in the grazer assemblage. The results indicated competition in the grazer assemblage at MNP as its WR is 1.40 and therefore grazers are tightly packed. However, as several species with similar body weight coexisted at MNP, the Hutchinson’s Rule could not be supported. Habitat heterogeneity rather than the size of conservation area related to species-packing and MNP with its low habitat heterogeneity showed a low degree of species-packing. Possible explanations have been advanced for existing ecological holes within the assemblage. Species-packing could still be a reasonable measure of the characteristics, dynamics, interactions and the patterns of assemble in animal communities. It could also be used to predict the effect of animal species loss or arrival on the stability of a natural ecosystem and provide useful guidelines in planning herbivore conservation measures in protected areas.
  • Use of Corn Cob and Rice Husk Biochar as Liming Materials in Acid Soils

    Frimpong Manso, E.; Nartey, E. K.; Adjadeh, T. A.; Darko, D. A.; Lawson, I. Y.D.; Amoatey, C. A. (Ecological Laboratory Unit, University of Ghana, 2020-01-22)
    Most soils in Ghana are acid with those of the Evergreen Rain Forest belt having Al toxicities. Unavailability, high cost and poor grade of conventional liming materials have led to poor yields of food crops grown on these acid soils. Preliminary works on biochar produced from agricultural waste in Ghana have shown that some types have high concentration of basic cations and contain CaCO3, an active ingredient in conventional lime. Biochar could, therefore, be exploited for use as liming material.  However, the biochar type that would be ideal for use as liming material in acid soils of Ghana has received little attention. Two typical acid soils viz., Typic Hapludox and Typic Hapludult were thus amended with corn cob and rice husk charred at 500 and 700 oC at a rate of 80 Mg/ha in a screen house experiment to evaluate their respective efficacies as substitutes for conventional agricultural lime. The Ca equivalent of the biochar types from CaCO3, the conventional lime, was amended to the soils to serve as realistic controls. The amended soils, in addition to their un-amended counterparts, were all kept at 80% field capacity in a completely randomized design in the screen house to allow for pH equilibration amidst weekly pH and bi-weekly exchangeable Al, Ca and Mg monitoring. Results showed that corn cob charred at 500 oC was able to raise pH from 4.2 to 5.2 in Hapludox and from 4.9 to 6.2 (an optimum pH for most food crops) in Hapludult within a six-week incubation period. All the biochar types reduced Al concentration from 0.4 cmolc /kg to undetectable levels in the Hapludult. The element was reduced from 1.3 cmolc /kg to 0.45 cmolc /kg in the rice husk and corn cob charred at 700 oC amended Hapludox.
  • Assessment of plant communities' pattern and diversity along a land use gradient in W Biosphere Reserve, Benin Republic

    Houessou, L. G.; Lykke, A. M.; Teka, O. S.; Adomou, A. C.; Oumorou, M.; Sinsin, B. (Ecological Laboratory Unit, University of Ghana, 2020-01-23)
    Human disturbance on vegetation is an important concern in biodiversity conservation. In this study we assessed how anthropogenic disturbance affected plant communities pattern, diversity, life form and chorotype composition along a land use gradient. Vegetation relevés were performed along a land use gradient (park-buffer zone-communal land) at W Biosphere Reserve in Benin. Non-metric multidimensional scaling (NMS) was used to assess plant communities patterns. Indicator species were determined for each plant community and land use. Plant community diversity, life forms and chorotypes composition were assessed and compared among land uses using one-way analysis of variance. NMS ordination showed a good separation between relevés of the park and those from the communal land while relevés of buffer zone were mixed within the park and communal land relevés. There was no significant difference between species richness among land uses types (F = 0.68; p = 0.529, ANOVA test at a level of significance of 5%). The Pielou evenness for the plant communities was higher in the park (E= 0.69±0.04) and buffer zone (E = 0.61±0.13) than in the communal lands (E = 0.44±0.02) while Shannon index showed no clear pattern along land use gradient. Therophytes abundance was significantly higher in the communal land while hemicryptophytes abundance was significantly higher in the park. Wide-distributed species abundance was significantly higher in the communal land whilst Sudanian species showed significantly higher abundance in the park. We concluded that monitoring of the indicator species of the plant communities and their traits are relevant tools for managers to follow-up changes in plant communities.
  • A Simple Alkaline Hydrolysis Method for Estimating Nitrogen Mineralization Potential of Soils

    Dodor, D. E.; Tabatabai, M. A. (Ecological Laboratory Unit, University of Ghana, 2020-01-23)
    A simple, precise and rapid alkaline hydrolysis method for determining nitrogen (N) availability index of soils is described. It involves direct steam distillation of 1 g field-moist soil and 1 M KOH, NaOH, LiOH or phosphate-borate buffer (pH 11.8) and the amount of NH4+-N released trapped in boric acid and its concentration determined successively every 5 min for a total of 40 min. The cumulative N hydrolyzed was fitted to a hyperbolic equation to determine the maximum hydrolyzable N (Nmax) and the time required to hydrolyze one-half of Nmax (Kt) by linear regression of the transformed data. First-order equation was also used to estimate the potentially hydrolyzable N (No), hydrolysis rate constant (k) and the time required to hydrolyze one-half of No (t1/2). Results showed that for each soil and reagent, Nmax and No values were similar, but differed significantly among soils, suggesting differences in the chemical nature or reactivity of organic N in the soils. In general, Nmax and No values ranged from 401 to 1667 mg kg-1 soil and accounted for 12-56% of total organic N in the soils. The Kt values ranged between 15 and 30 min. Among the reagents tested, KOH and NaOH showed the best promise for estimating the total hydrolyzable organic N pool in the soils. The Nmax and No values were significantly correlated with the amounts of N mineralized in two weeks under aerobic and anaerobic conditions at 30 oC, N released by 2 M KCl extraction at 80oC for 20 h, and the initial NH4+-N present in the soils. We concluded that direct steam distillation of soils with 1M KOH or NaOH offer a quick and precise mean for estimating the potentially mineralizable organic N pool and availability index in soils.
  • Adaptive strategies of smallholder farming systems to changing climate conditions in the vicinity of Kogyae Strict Nature Reserve within the Forest-Savanna Transitional Zone of Ghana

    Pabi, O.; Ayivor, J. S.; Ofori, B. D. (Ecological Laboratory Unit, University of Ghana, 2020-01-23)
    The strong climate linkages to farming systems render them and dependent communities vulnerable to climate change and variability. Knowledge of existing responses to climate change is important for the formulation of policies and adaptive strategies for resilience. The paper examines a fifty-year climatic record from 1961-2011, community perceptions, experiences and knowledge for evidence of climate change and impacts. Climate change-driven farmer adaptive responses were critically examined relative to farming practices; and crop climatic requirements for growth, development, maturity and harvesting. A mixed methodological approach was adopted to address issues of climate change, exposures, sensitivities and adaptive responses. The results showed that the area has experienced a steady rise in temperature, reduced rainfall amounts of 3.0mm per annum, reducing events of rainfall excesses and increasing deficits, narrowing of rainfall period and a shift of the double to a single rainfall maxima regime. Farmers have observed these patterns of changes and experienced the impacts. Consequently, evidence-driven adaptive responses in the transformation of farming practices, timing of cultivation and choice of crops have been developed by farmers. It is recommended that further adaptive strategies be planned to improve farmers’ adaptive capacities and reduce sensitivity of crops to climate perturbations.
  • Bioenergy: Biodiesel from Freshwater Green Microalgae and a Cyanobacterium Occurring in Ghana

    Doamekpor, L. K.; Onwona-Agyeman, R.; Ameka, G. K. (Ecological Laboratory Unit, University of Ghana, 2020-01-23)
    Biodiesel from freshwater green microalgae, and cyanobacteria holds promise as an alternative to replace petroleum diesel to meet the energy demands for transportation, industry and domestic use. In this study, three green freshwater microalgae (Closterium acerosum Ehrenberg ex Ralfs, Oedogonium ciliatum Pringsheim ex Hirn, and Spirogyra africana (F.E.Fritsch) Czurda), and a freshwater cyanobacterium (Chroococcus turgidus (Kützing) Nägeli) occurring in Ghana, were assessed to verify their suitability for biodiesel production. Samples of the species were collected from the Weija Lake; and the green freshwater microalgae were cultured in Bold’s Basal Medium while the cyanobacterium was cultured in BG-11 (Blue-Green Medium) medium, in photo-bioreactors for 14 days. Algal lipids were extracted from dry biomass of the species with hexane and diethyl ether, and biodiesel produced from the lipids by base-catalysed transesterification. The amount of lipid extracted from the species varied from 20.3 in Spirogyra to 38.2% dry wt. in Oedogonium. Biodiesel produced also varied from 6.7 in Spirogyra to 22.3% dry wt. in Closterium, and the values fell well within the range reported for such organisms around the world. We suggest that many more microalgae occurring in Ghana should be sampled for their lipid content in future work on biodiesel production and development in the country.
  • A Theoretical Study of Subsurface Drainage Model Simulation of Drainage Flow and Leaching in Salt Affected Irrigated Fields

    Ampofo, EA; Tanton, TW (Ecological Laboratory Unit, University of Ghana, 2014-09-19)
    A three-dimensional variable-density groundwater flow model, the SEAWAT model, was used to assess the influence of subsurface drain spacing, evapotranspiration and irrigation water quality on salt concentration at the base of the root zone, leaching and drainage in salt affected irrigated land. The study was carried out on a conceptual uniform homogenous irrigated field of shallowwatertable depth of 0.5m and aquifer salt concentration of 7200 mg/l with an impermeable layer at 10 m depth and impermeable field boundaries. The model was run for 10 years with an irrigation rate (applied recharge) of 8 mm/d and salt concentration of 1,500 mg/l, over a range of drain spacings. During the 10-year drainage period, the simulated concentrations at the base of the root zone and the discharge rates were the same at all the spacing when evapotranspiration was not included. However, upon inclusion of evapotranspiration, the simulated concentration at the base of the root zone ranged from about 5,200 to about 6200 mg/l, the discharge rate ranged from 2.3 to 1.9 mm/d. When the applied recharge concentration was changed to 1,000 mg/l and 700mg/l, but with all the other parametersmaintained, the simulated concentration at the base of the root zone ranged from 3,700 to 4,400 mg/l, and from 2,800 to 3200 mg/l for the different spacing, respectively.
  • Assessing the Efficacy of Azadirachta indica Seed Extract on Fusarium Oxysporum

    Oladipo, OG; Ogunkanbi, D.A.; Ayo-Lawal, R. A. (Ecological Laboratory Unit, University of Ghana, 2016-02-15)
    Global population pressure has posed great challenge on food security with over 800 million people having no access to adequate food and about two billion faced with hunger and malnutrition. Banana (Musa spp.) is the world’s fourth most important global food crop after rice, wheat and maize in terms of production. The cultivation of banana is however threatened by pests and diseases and diverse anthropogenic activities which have influenced and changed the climate. Generally, climate change impacts on agriculture and food security across the globe decreasing crop productivity while extreme weather conditions such as flooding, drought, hurricanes etc. increase disease transmission. Fusarium oxysporum, a soil borne fungus affects banana production, causing vascular wilts and damage to banana plantations by infecting plant roots, cortex and stele. Several fungicides have been employed to curb these losses. Plant extracts have, however, played significant role in the inhibition of seed-borne pathogenic F. oxysporum. Eco-friendly Neem (Azadirachta indica) extracts have been reported to gain prominence over inorganic fungicides. This study investigated the effectiveness of Neem (Azadirachta indica) seed extract at varying concentrations of 10, 20 and 50% against F. oxysporum in Potato Dextrose medium for 120 h. using pour plate and cork boring methods. The results obtained showed inhibited growth of the test fungus with 50% having the greatest percentage inhibition. This indicates that A. indica seed extract has fungicidal effect on F. oxysporum and has the potential to curb banana losses and hence enhance banana production and thus ensure food security.
  • Assessment of Helminth Infections in Goats Slaughtered in an Abattoir in a suburb of Accra, Ghana

    Futagbi, G.; Abankwa, J.K.; Agbale, P.S.; Aboagye, I.F. (Ecological Laboratory Unit, University of Ghana, 2016-02-15)
    A cross-sectional study to evaluate parasitic infections in small ruminants was conducted in an abattoir in a suburb of Accra from January to March 2015. Samples from various sections of the gut of 35 goats, either reared in Ghana or imported from Burkina Faso, were analyzed using the Kato-Katz technique. The overall prevalence was 100%. The proportions of goats infected with each parasite type were 100%, 94.4%, 88.6%,80.5%, 68.6 62.8% and 44.4% respectively for Strongyloides sp., tapeworms, Ascaris sp., Fasciola hepatica, Trichuris sp., Haemonchus contortus and Schistosoma haematobium. The proportion of animals infected with Haemonchus contortus was significantly higher in imported goats than those reared locally (p<0.05). The mean intensity of infection was low for all the parasites. However, high diversity of parasites with 80% of goats having at least four parasite types was observed. The data show high multiple infections in the goats brought to the slaughter house and suggest the need to institute appropriate measures to curb the problem.
  • Comparison of Several Methods to Estimate Reference Evapotranspiration

    Zarei, AR; Zare, S; Parsamehr, AH (Ecological Laboratory Unit, University of Ghana, 2016-02-15)
    Evapotranspiration is one of the major components of the hydrologic cycle is highly important in studies relevant to design and management of irrigation systems. The knowledge of the evapotranspiration of natural ecosystems and plant populations is of fundamental importance in several branches of science, research and practical uses. Nevertheless, the harmonization of the large number of methods and user needs often causes problems. The aim of these analyses was to explore the output range and sensitivity of models of different physical approaches under local conditions. In this study, evapotranspiration (ET0) was determined by several models include: Penman-Monteith-FAO-56, Blaney-Criddle, Hargreaves-Samani modified 2, Pan Evaporation, Jensen-Haise and Thornthwait in the Garebayegan research station at Fars province. Penman- Monteith-FAO-56 was reference model. Results of this research show that Pan Evaporation method, Hargreaves-Samani modified 2 and Blaney-Criddle have not significant difference by Penman-Monteith- FAO-56 in (P value< 0.05 level). Pan Evaporation method has most similarity to Penman-Monteith-FAO-56. Jensen-Haise and Thornthwait models have significant difference by Penman-Monteith-FAO-56 in (P value< 0.01 level). Thornthwait model has most difference by Penman-Monteith-FAO-56.
  • Awortwi et al.: Mixing and stratification relationship on phytoplankton of Lake Bosomtwe (Ghana) 43 West African Journal of Applied Ecology, vol. 23(2), 2015: 43–62. The Relationship Between Mixing and Stratification Regime on the Phytoplankton of Lake Bo

    Awortwi, F.E.; Frempong, E.; Aikins, S. A.; Hecky, R. E.; Hall, R.; Puchniak, M. (Ecological Laboratory Unit, University of Ghana, 2016-02-15)
    The seasonal changes in the phytoplankton community in terms of biomass composition and associated physicochemical parameters of the Lake Bosomtwe (Ghana) located in West Africa were studied between 2004 and 2006 to assess the mixing and stratification regime of the lake on the phytoplankton dynamics. From water samples obtained from a central index station, biomass composition was assessed by converting phytoplankton counts to wet weights-based approximation into cell volume values; whiles mixed layer and euphotic depths were analyzed using temperature and light profiles of the lake respectively. Total phosphorus was estimated using the Ascorbic Acid Method. Results from the dataset showed that the phytoplankton biomass was dominated by the Cyanophyceae throughout the study period despite the seasonal changes associated with the mixing and stratification regimes. There were significant inter-annual differences in the mean values of the euphotic depth and the wet weight biomass (P < 0.05). However differences in the mean values of the mixed layer depth, the ratio of the mixed layer depth:euphotic depth, and total phosphorus concentration (P > 0.05) were insignificant. High variations in the mixed layer depth (CV > 34 %) and the euphotic depth (CV > 32) drive similarly high variations in the wet weight biomass (CV > 28) as is the case for many stratifying tropical lakes. However, both were poor predictors of the phytoplankton wet weight biomass behaviour (mixed layer depth, r2 = 0.1034; euphotic depth, r2
  • A Survey of the Benthic Macrofauna and Fish Species Assemblages in a Mangrove Habitat in Ghana

    Tawiah, P; Longdon-Sagoe, M; Okyere, I; Dotsey-Brown, J; Asare, NK; Aheto, DW; Wemegah, Y; Dzakpasu, MFA (Ecological Laboratory Unit, University of Ghana, 2014-09-19)
    In order to enhance ecological knowledge for coastal and mangrove  ecosystem conservation in Ghana, the study documents the taxonomic groups of benthic macrofauna and fish assemblages in an urban mangrove swamp as its fundamental objective with emphasis on their composition, richness and diversity. This is because benthic and fish fauna of mangrove habitats are amongst the least studied biota in Ghana. Fish and benthos sampling was undertaken from five randomly selected pools within a mangrove stand during the wet and dry seasons using pole-seine net (7 m long and 1.5 m depth, with stretched mesh size of 5 mm) and an Ekman grab (15 cm × 15 cm dimensions), respectively. All samples were  preserved in 10% formalin for laboratory analysis. The results indicated a more diverse macrozoobenthic community in the wet (H¹ = 1.8) than dry season (H¹ = 1.5) . Overall, five out of a total of 13 genera found are intolerant to pollution and four moderately tolerant, while four comprising polychaetes and the midge Chironomus, are pollution tolerant. This suggests that the mangrove habitat is less polluted. A grand total of 917 fish specimens, belonging to 15 species and nine families, were encountered for both seasons (371 and 546 specimens for wet and dry seasons, respectively). The black-chinned tilapia, Sarotherodon  melanotheron, was the dominant fish species in the wet season, accounting for 54.2% of the total fish caught, whilst the grey mullets, Mugil babanensis and Mugil curema, were the dominant species in the dry season, with a combined total of 51.4% of the fish population. However, over 70% of these dominant fish species from both seasons were juveniles providing a strong justification for the observation that the mangrove habitats are nursery grounds for fish inhabiting adjacent riverine, estuarine and inshore marine habitats. Considering this relevance of mangroves and the ongoing conversion attempts of mangrove habitats to other land uses, a concerted mangroves conservation effort is strongly advocated.
  • Using Machine Learning for Land Suitability Classification

    Aminzadeh, F; Zarei, AR; Mokarram, M; Hamzeh, S (Ecological Laboratory Unit, University of Ghana, 2015-09-10)
    Artificial intelligence and machine learning methods can be used to automate the land suitability classification. Multiple Classifier System (MCS) or ensemble methods are rapidly growing and receiving a lot of attention and proved to be more accurate and robust than an excellent single classifier in many fields. In this study a dataset based land suitability classification is addressed. It is done using a newly proposed ensemble classifier generation technique referred to as RotBoost, which is constructed by combining Rotation Forest and AdaBoost, and it is known to be the first time that RotBoost has been applied for suitability classification. The experiments conducted with the study area, Shavur plain, lies in the northern of Khuzestan province, southwest of Iran. It should be noted that suitability classes for the input data were calculated according to FAO method. This provides positive evidence for the utility of machine learning methods in land suitability classification especially MCS methods. The results demonstrate that RotBoost can generate ensemble classifiers with significantly higher prediction accuracy than either Rotation Forest or AdaBoost, which is about 99% and 88.5%, using two different performance evaluation measures.
  • Effect of Duration of Reclamation on Soil Quality Indicators of a Surface – Mined Acid Forest Oxisol in South – Western Ghana

    Tetteh, E. N.; Logah, V.; Twum-Ampofo, K.; Partey, S. T. (Ecological Laboratory Unit, University of Ghana, 2016-02-15)
    The quality of degraded mined soils can be restored through effective reclamation practices. In this study, we evaluated the impact of varying duration of land reclamation on soil quality at AngloGold Ashanti, Iduapriem mine Ltd., Tarkwa, Ghana. Soil samples were taken from mined sites of the Company at various stages of phytoremediation: 2, 5, 9 and 11 year old reclaimed sites. The soils were analyzed for soil quality indicators. A nearby forest reserve representative of the pre-degraded condition was used as the control. Prior to phytoremediation with multipurpose agroforestry trees, the mined soils were subjected by the Company to earthworks/slope battering followed by spreading of oxide materials over the surface, construction of crest drains and cover cropping. Having determined the impact of the varying duration of reclamation on soil quality indicators, separate pot experiments involving maize and cowpea were set up using soils from the sites to assess heavy metals accumulation in the cultivated crops. Soil nutrient levels in the sites under reclamation were significantly higher (P < 0.05) than the nearby forest reserve. Soil pH though generally low, was relatively higher (P < 0.05) in sites under reclamation than in the control. Soil total nitrogen, available phosphorus and exchangeable potassium levels were highest (P < 0.05) in the 11 year old site. Zinc contents of all sites were below the maximum permissible levels. There was somewhat antagonistic interaction between zinc and phosphorus contents of maize in the unclaimed site. Though heavy metal concentrations in maize were lower than that of cowpea, the concentrations in both plants were generally beyond the permissible levels suggesting a possible transfer onto the food chain if the crops are included as part of rotation programmes from the agronomic perspective. Our results indicate that phytoremediation of mined lands using agroforestry multipurpose trees could be marginal even after a decade of reclamation.
  • The Impact of Harvest Frequency on Herbage Yield and Quality of Cynodon nlemfuensis

    Timpong-Jones, E.C.; Adjorlolo, L. K.; Ayizanga, R. A. (Ecological Laboratory Unit, University of Ghana, 2016-02-15)
    Ruminants in Ghana experience feed deficit in the dry season leading to loss of weight and condition. To curb this problem of weight loss, there is the need to raise their plain of nutrition in the critical months of the year when feed is low in quantity and quality. This can be achieved by maximising forage production through appropriate harvest management practices. This study sought to find the effect of repeated harvest on dry matter (DM) yield of Cynodon nlemfuensis (Cynodon) in the coastal savanna of Ghana. It was hypothesised that infrequent repeated harvest will improve DM yield and nutritive value of Cynodon. An area of 7.0 m by 5.5 m was used for a two year study (2013 and 2014). The treatments were harvest of Cynodon at 24 (T1), 12 (T2) and 6 (T3) weeks intervals. The Randomised Complete Block Design was used with four replicates per treatment. Dry matter yield and plant cell wall constituents viz. NDF, ADF and Cellulose contents decreased significantly (P < 0.05) in the order T3<T2<T1, indicating that DM yield and plant cell wall constituents decreased with increasing harvest frequency. Crude protein content (CP) decreased significantly (P < 0.05) in the order T1<T2<T3, indicating that CP content increased with increasing harvest frequency. The study has shown that repeated harvest of Cynodon provided lower DM yield of better quality, with harvest at six weeks interval exceeding the minimum CP level required for adequate intake and digestibility by ruminant livestock.
  • Cross-resistance assessment in cartap- and esfenvalerateselected strains of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae)

    Ninsin, KD (Ecological Laboratory Unit, University of Ghana, 2016-02-15)
    Effective control of the diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae) has become critical due to the genetic ability of the insect pest to develop resistance to insecticides. Alternating or rotating the use of insecticides that do not show cross-resistance is an important component of an effective resistance management strategy, as it helps prevent resistance development or regain susceptibility in an already resistant arthropod pest population. In this study, cross-resistance to selected insecticides in cartap- and esfenvalerate-selected strains of DBM was assessed in the laboratory, using the leaf-dipping method. The esfenvalerate-selected strain exhibited moderate cross-resistance to abamectin and a very low cross-resistance to cartap. The cartap-selected strain also displayed a very low cross-resistance to esfenvalerate but showed no cross-resistance to abamectin. Alternating cartap and abamectin would therefore help to effectively manage insecticide-resistance development in the DBM.
  • Diversity and response of Benthic Macroinvertebrates to Natural and Induced Environmental Stresses in Aiba Stream, Iwo, Southwestern Nigeria

    Akindele, EO; Liadi, AA (Ecological Laboratory Unit, University of Ghana, 2014-09-19)
    Aiba stream, a tropical stream in southwestern Nigeria, was investigated on monthly basis from November 2012 to April 2013 with a view to comparing their response with the Biological Monitoring Working Party (BMWP) score system already in use in some eco-regions. The diversity and response of benthic macroinvertebartes were used in assessing the biological water quality and health status of the stream. Samples were collected from four different stations using the Kick Sampling Technique. All the specimens collected were preserved in 70% alcohol solution and later identified in the laboratory using relevant identification guides. Predatory invertebrates like water scorpions (Nepa and Rana spp.) and dragonfly nymphs (Macromia sp.) were sorted out in-situ and stored separately. Nineteen taxa of macroinvertebrates were recorded comprising three Phyla, four classes and 17 families. The overall Shannon-Weiner diversity and Margalef’s indices of the stream indicated that the stream was organically polluted, as evidenced by the presence of some pollution-tolerant macroinvertebrates (e.g. Families Stratiomyidae, Nepidae, Planorbidae, Chironomidae and Syrphidae). Although there were some similarities between the BMWP score system and the response of the benthic macroinvertebrate families to environmental stress, a disparity was also observed between the two which underscores the need to carry out intensive research in this regard and adapt a BMWP score system for regional freshwaters in the tropics.

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