11 research outputs found
Figure 8 from: Houngnon A, Adomou AC, Gosling WD, Adeonipekun PA (2021) A checklist of vascular plants of Ewe-Adakplame Relic Forest in Benin, West Africa. PhytoKeys 175: 151-174. https://doi.org/10.3897/phytokeys.175.61467
No full textFigure 8 Ewe Adakplame Relict Forest in a matrix of savanna and agriculture landscape A forest edge affected by anthropogenic activities (Samsung photo A. Houngnon 2017) B Landscape of fallow and field around the edge of the forest ecosystem (Olympus photo A. Houngnon 2016)
Distribution of palynomorphs in recent bottom sediments offshore Niger delta: A preliminary study
No full textInternational audienc
Investigating the Phytochemicals and Antimicrobial Properties of Three Sedge (Cyperaceae) Species
No full textIn order to evaluate the medicinal value of notorious sedge weeds, three species:Cyperus esculentus, Cyperus rotundus and Mariscus alternifolius were investigated for their phytochemical constituents and antimicrobial properties. Preliminary qualitative phytochemical constituents and in vitro antimicrobial activities were evaluated against four fungi species: Aspergillus niger, Aspergillus fumigatus, Penicillium chrysogenum and Candida albicans, and three bacteria species: Escherichia coli,Salmonella typhi and Staphylococcus aureus. Two solvents, water and ethanol, were used to produce the extracts and were screened for their antimicrobial activity. Antimicrobial activity evaluation of the extracts against pathogens was carried out at 100 mg/ml concentration by Disc Diffusion method for fungi, Disc Diffusion and Agar Well Diffusion methods for bacteria. Observed activities were related to standard antibiotics, antifungal and antibacterial, which served as controls. Phytochemically, the plant extracts showed the presence of carbohydrates, flavonoids, ketose sugars, steroids, reducing sugars and tannins. The ethanolic extract of C. rotundus exhibited the highest activity against A. niger, E. coli and S. aureus. No extract was active against C. albicans. From these findings, it was concluded that C. rotundus is a potential source of bioactive compounds for new drugs upon isolation and purification for treating infections caused by these pathogens.</p
Antimicrobial Properties and Melissopalynology, Proximate and Elemental Analyses of Honey Samples from Three Different Ecozones in Nigeria
No full textHoney samples from three different ecozones - coastal freshwater (Ogba), lowland rainforest (Oka-Akoko) and montane Sudan savanna (Mambilla plateau) – were subjected to melissopalynological, proximate and elemental analyses, as well as antimicrobial studies. The aim of the research was to determine the contribution of pollen, if any, in the antimicrobial activities of the studied honey samples. Standard preparation methods were adopted for these studies. The Mambilla honey recorded the highest pollen diversity, while that of Oka-Akoko and Ogba regions had similar diversity, both having lower values. The Ogba honey however contained the highest abundance of pollen. Proximate analysis showed that the Mambilla honey also recorded the highest values of moisture, ash, protein, fats and oil, as well as potassium and reducing sugars. Antimicrobial investigation revealed the highest antimicrobial activities for the Mambilla honey, followed by Oka-Akoko and Ogba against Staphylococcus aureus (gram positive) and Pseudomonas aeruginosa (gram negative). Moisture content, proteins and carbohydrates were significantly different, with positive and negative trends respectively, when related with the antimicrobial activities of the honey samples. The pollen contents were also qualitatively different. This is the first time the antimicrobial activity of honey is ever traced to pollen contents. More conclusions can be accurately made only after further research upon pollen grains directly.</jats:p
A checklist of vascular plants of Ewe-Adakplame Relic Forest in Benin, West Africa
No full textCovering 560.14 hectares in the south-east of Benin, the Ewe-Adakplame Relic Forest (EARF) is a micro-refugium that shows insular characteristics within the Dahomey Gap. It is probably one of the last remnants of tropical rain forest that would have survived the late Holocene dry period. Based on intensive field investigations through 25 plots (10 × 50 m size) and matching of herbarium specimens, a checklist of 185 species of vascular plant belonging to 54 families and 142 genera is presented for this forest. In addition to the name for each taxon, we described the life form following Raunkiaer’s definitions, chorology as well as threats to habitat. The Rubiaceae family was the richest (20 species) followed by the Fabaceae (15 species). Life forms showed the preponderance of phanerophytes (88%). The Chorological spectrum was dominated by Guineo-Congolean species (66%). Species richness estimated were 200.52 ± 9.2808 for Bootstrap; 217.62 ± 14.5972; 224.16 ± 15.3725 and 242.67 respectively for Chao, Jacknife1 and Jacknife2. Bootstrap appears to be the estimation closer to the field records. In Benin, EARF is home for Rinorea species described as West African forest bio-indicators and single location for Nesogordonia papaverifera, Mansonia altissima, Englerophytum oblanceolatum, Octolobus spectabilis, Vitex micrantha and most of Drypeteae tribe species (Drypetes aframensis, Drypetes afzelii, Drypetes gilgiana and Drypetes leonensis) recorded in Benin. Our results provides baseline information for further in-depth analysis of vegetation history in Benin by raising the question on the past floristic connection of the Dahomey gap and community engagement in conservation
Antimicrobial Properties and Melissopalynology, Proximate and Elemental Analyses of Honey Samples from Three Different Ecozones in Nigeria
No full textHoney samples from three different ecozones - coastal freshwater (Ogba), lowland rainforest (Oka-Akoko) and montane Sudan savanna (Mambilla plateau) – were subjected to melissopalynological, proximate and elemental analyses, as well as antimicrobial studies. The aim of the research was to determine the contribution of pollen, if any, in the antimicrobial activities of the studied honey samples. Standard preparation methods were adopted for these studies. The Mambilla honey recorded the highest pollen diversity, while that of Oka-Akoko and Ogba regions had similar diversity, both having lower values. The Ogba honey however contained the highest abundance of pollen. Proximate analysis showed that the Mambilla honey also recorded the highest values of moisture, ash, protein, fats and oil, as well as potassium and reducing sugars. Antimicrobial investigation revealed the highest antimicrobial activities for the Mambilla honey, followed by Oka-Akoko and Ogba against Staphylococcus aureus (gram positive) and Pseudomonas aeruginosa (gram negative). Moisture content, proteins and carbohydrates were significantly different, with positive and negative trends respectively, when related with the antimicrobial activities of the honey samples. The pollen contents were also qualitatively different. This is the first time the antimicrobial activity of honey is ever traced to pollen contents. More conclusions can be accurately made only after further research upon pollen grains directly
The Late Quaternary vegetational and environmental history of western tropical Africa: the eastern Benin Basin, Lagos, Nigeria
No full textA palynological study of a 30 m borehole within the Akoka campus of the University of Lagos, Akoka, Nigeria revealed Late Quaternary paleo-vegetational, climatic and environmental changes. Sixteen samples at a regular interval of 2 m were subjected to standard palynological and sedimentological techniques. Six pollen zones representing six paleoclimatic phases within the Late Quaternary period were recognized. The age model is based on two radiocarbon dates (6 m: 5,495 } 25 14C yr and 12 m: 15,660 } 40 14C yr) and, by extrapolation, the sequence spans approximately the last 35,000 yr BP. The African maximum transgression and the African Humid Period (wet paleoclimate maximum) – the Nouaktchottian, and Pre-Nouaktchottian respectively – were recognized, while the Ogolian II (Erg II) was stratigraphically recognized and the Upper Inchirian extrapolated. Recovered diatom frustules with other proxies were employed for paleoclimatic and paleoecological deductions. Four hydrological cycles and three paleoecological settings were identified. Results from this work indicate the co-eval record of paleoclimatic events across Africa, suspected cooling during the African maximum transgression in Nigeria and the usefulness of coastal freshwater swamp sediments for paleoclimate studies
Airborne Pollen Records of Shomolu Local Government Area in Lagos State
No full textData on the prevalence of pollen in the atmosphere is limited and almost non-existent for Lagos State and Nigeria. Pollen grains are known to be highly allergenic and thus they are potential causes of respiratory diseases. To investigate airborne incidence of pollen, so as to construct a pollen calendar and contribute to current trends in the development of aeropalynology/allergy study in Nigeria, three highly populated locations in Shomolu Local Government areas of Lagos State: University of Lagos, Bariga and Gbagada, were sampled. Aero-samplers were harvested monthly from January 2013 to December 2013. After acetolysis treatment and analysis, the total pollen count was 4393, belonging to 38 pollen taxa and 29 families. The main taxa include Poaceae, Cyperaceae, Amaranthaceae, Ludwigia and Alchornea. Monthly pollen counts were highest in October and lowest in June. Almost three-quarters of the total pollen content came from grasses and weeds. This composition reflects the ornamental and grassland flora of the town, as well as the natural vegetation surrounding the urban area. The total pollen concentration correlates positively with the temperature and negatively with the wind, rainfall and relative humidity, which was similar in the dominant taxa Amaranthaceae and Alchornea. Dominant taxa Cyperaceae and Ludwigia have significant positive correlation with wheezing cough. Results from this work will form the basis for a forecast service required to inform and educate the general public and allergy sufferers about pollen distribution in Lagos State
Long‐term drivers and timing of accelerated vegetation changes in African biomes and their management implications
No full textAim: Owing to its diverse bioclimatic zones, long human history and intense anthropogenic impacts, Africa provides a model system for studying how global terrestrial ecosystems might respond to accelerated socio-environmental stress. Africa is particularly vulnerable to climate change and human impact, and insufficient baseline data hamper current environmental management efforts. Using palaeoecological data, we seek to identify the timing, pace and drivers of change in African biomes on a long-term scale to inform current ecosystem management frameworks on the continent. Location: Africa. Time period: 0–12 ka. Major taxa studied: African biomes. Methods: Sixty-four pollen records across Africa and nearby sites were retrieved from multiple databases/sources and grouped into biomes. Turnover (quantified using the squared chord distance dissimilarity metric) and rarefaction analyses were conducted on pollen records in each biome group to reconstruct regional temporal vegetation turnover and richness. Reconstructed vegetation turnover and richness were compared with independent records of climate, fire and human activity to identify possible drivers of change. Results: We found that the most stable biomes were those with the greatest floristic richness. Southern Africa's mediterranean-type (SAM) ecosystems were the most stable and northern Africa's mediterranean-type (NAM) ecosystems were the most unstable (mainly owing to fire). Tropical savannas (TS) and SAM ecosystems expressed the most sensitivity to climatic shifts from ≥6 ka, whereas tropical forests (TF) were relatively stable before human activities intensified from c. 2 ka. Floristic richness also declined across the tropics from c. 2 ka. Main conclusions: Our analysis pinpoints NAM ecosystems as undergoing the fastest acceleration in turnover on the continent in response to fire, whereas TF and TS have been undergoing unprecedented changes in biodiversity in the last 2,000 years. We expect further changes in biodiversity where climate becomes warmer and drier and where human impacts are novel and rapid in comparison to long-term baselines.Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Grant/Award Number: CE17010001
Comparative palynology of Macrotermes sp. mounds and Vespula vulgaris nests on the University of Lagos campus, Akoka: preliminary study
No full textAbstractIn order to assess the environmental indicator potential of wasp nests and termite mounds, the palynomorph content of three randomly selectedMacrotermessp. mounds (termitaria) and twoVespula vulgarisnests collected on the University of Lagos campus were examined. Palynological analysis showed the presence of 298 well-preserved palynomorphs showing characteristic morphological features. The recovered palynomorphs included pollen, pteridophyte spores and fungal spores, along with insect parts (106), diatoms (7) and a protist (1). The pollen assemblage of termite mounds comprised 78 pollen and pteridophyte spores, with Poaceae and Arecaceae pollen as dominants. In the wasp nest the pollen assemblage comprised 28 pollen and spore taxa, with Poaceae and Arecaceae pollen also dominant. Both mounds and nests had, besides diatoms, six pollen and spore taxa: Poaceae, Amaranthaceae, Pteridophyte spores, Arecaceae,Raffiasp. andRhizophorasp. Vegetational grouping of the recovered pollen and spores indicated five phytoecological groups: secondary forest, mangrove swamp forest, freshwater, open vegetation and Poaceae. In statistical analyses, termite mounds had a higher species richness value (2.08 as compared to 1.99 from the wasp nests), while the wasp nests had a higher species diversity value (0.997 as compared to 0.845 from the termite mounds). Pollen analyses of the termite mounds and wasp nests suggest that both could be useful tools in environmental studies. This is the first attempt to evaluate the potential of termite mounds and wasps nest as natural pollen accumulators in Nigeria. The results suggest new possibilities for the use of the pollen records preserved in termite mounds and wasp nests for environmental studies.</jats:p
