Botany-Scholarly Publications

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Browsing Botany-Scholarly Publications by Author "Adekanmbi, O."

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    Open Access
    Palynological Study of Recent Sediments from an Urban Creek in Lagos State, Southwestern Nigeria
    (2019) Adekanmbi, O.; Ajikah, L.; Ogundipe, O.T.; Durugbo, E.
    A palynological study of recent sediments from Ijora Creek, an Urban Creek in Lagos, Southwestern Nigeria was carried out to provide inferences on paleovegetation and climate change over time in the study area. Two stations 90m apart were sampled at low tide in a boat using a Russian peat corer. Samples were taken at 10cm intervals and eighteen sediments samples were collected and processed using standard palynological methods. Two hundred and sixty six (266) and two hundred and thirty three (231) palynomorphs were recovered from stations 1 and 2 respectively. Palynomorphs recovered and identified to species level include Alchornea cordifolia, Hymenocardia acida, Elaeis guineensis, Spathodea companulata, Triumfetta pentandra, Uapaca acuminata, Tridax procumbens, Berlinia sp., Eugenia sp., Celtis sp., Albizia sp., Cyperus sp. together with species of Poaceae, Asteraceae, Arecaceae, Eurphorbiaceae, Acanthaceae, with common microforaminiferal test linings and fungal spores. Poaceae and fungal spores dominated the assemblage while station 1 recorded the highest pollen and spore abundance. The presence of microforaminiferal wall linings, fungal spores and the freshwater swamp species Alchornea cordifolia and the oil palm pollen Elaeis guineensis suggests a dominantly wet period in which, there was a marked marine transgression into the creek, interrupted occasionally by dry climate as inferred from the abundant records of Poaceae and Asteraceae. The presence of secondary forest species especially Elaeis guineensis suggests the impact of human activities on the paleovegetation.
  • Item
    Open Access
    Vegetation change inferred from the pollen record in recent sediments from around the Lagos-East coastal environment (SW Nigeria)
    (Sciendo, 2019) Adekanmbi, O.; Ajikah, L.; Ogundipe, O.T.
    Recent sediments from the coastal environment of Lagos East, Nigeria, were used to make a palynological reconstruction of the vegetation of the study area and to draw inferences about its palaeoclimate. A total of 8456 palynomorphs were recovered, dominated by pollen grains of Poaceae (13.96%), Cyperaceae (6.23%), Alchornea cordifolia Müll-Arg (8.36%) and Elaeis guineensis Jacq (2.41%). Others were Cyclosorus afer Ching (2.18%), Rhizophora sp. (0.45%), Nephrolepis sp. (1.03%), Celtis sp. (0.25%) and Pteris sp. (0.13%). The composition of the recovered palynomorphs suggests that the past vegetation was predominantly a mosaic of freshwater swamp, with open to dry climate, as indicated by the records of Cyperaceae, Alchornea cordifolia, Elaeis guineensis, Arecaceae, Asteraceae, Acanthaceae and Chenopodiaceae/Amaranthaceae. Radiocarbon dates obtained from two depths (surface and deepest) indicate that the sediments were deposited around the last 103.8 ± 0.4 pMC (percentage Modern Carbon) and 111.9 ± 0.4 pMC, hence in the late Holocene. The study identified fluctuations between wet and dry climatic conditions in the Holocene of this area.