DSpace Angular :: Browsing by Author "Isichei, Augustine O."

Browsing by Author "Isichei, Augustine O."

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Open Access
Acidification Potential in the Nigerian Environment
(1988) Isichei, Augustine O.; Akeredolu, Funso
The inability of developing countries to tackle pollution problems for economic reasons is a fact of life. In addition, due to the lack of knowledge in Nigeria about the environment, it is difficult to ascribe environmental changes to particular factors. Therefore, in viewing acidification caused by sulfur dioxide and oxides of nitrogen in Nigeria, the first problem is to identify the relationship between acidification and prevailing economic activities based on the experience of the developed world.
Open Access
Changes in a secondary forest in southwestern Nigeria following a ground fire
(1986) Isichei, Augustine O.; Ekeleme, Friday; Jimoh, Bakare A.
In January 1983, two 50 m x 50 m rain forest plots in the University of Ife campus in southwestern Nigeria were demarcated for a baseline study of species composition, litterfall and tree girth increments. By accident, a severe ground fire burnt one of the plots on 31 January, barely two weeks after litter traps had been set and species listing and fist girth measurements completed. The effect of this fire was assessed in the burnt plot after 14 months, in April 1984. The fire affected small trees especially, and there were indications that some species were more sensitive than others. Manihot glaziovii, which was present in the plot and abundant in its vicinity before the fire showed a big increase in density after the fire because it was able to germinate in the openings created by the fie. These observations were related to succession, and it is concluded that the observation by some workers that the initial composition of a regrowth forest may be partly predicted from a knowledge of the seed bank in the soil may be applicable in the present case.
Open Access
Cover crops reduce weed seedbanks in maize-cassava systems in southwestern Nigeria
(2003) Ekeleme, Friday; Akobundu, I. Okezie; Isichei, Augustine O.; Chikoye, David
Weeds are a major constraint to crop production in smallholder farms in tropical Africa. The weed seedbank and annual recruitment are the main sources of weed infestation in crops. This study was carried out in Ibadan, Nigeria, to evaluate the effect on the seedbank of two types of planted fallow (alley cropping with leucaena and live mulch with tropical kudzu) and a natural bush fallow under four land-use intensities. Type of fallow was the main plot. Land-use intensities, consisting of continuous cropping of maize intercropped with cassava, I cropping yr of maize-cassava followed by 1, 2, and 3 yr of fallow, were the subplots. Averaged over a 3-yr period, the seedbank was 55% lower in the tropical kudzu plots and 43% lower in the leucaena plots compared with natural bosh. The difference in seedbanks between plots cultivated after leucaena and natural fallow was 23%. Seed density of annual broadleaf weeds was high and dominated the seedbank of both planted and natural fallow. Overall, seeds of grasses occurred at low densities in all plots cultivated after 2 to 3 yr of fallow, whereas seeds of sedges occurred more in continuously cultivated plots and plots cultivated after 1 yr of Sallow in all the fallow types. Seed density of perennial broadleaf weeds increased as land-use intensity decreased. Live mulch with tropical kudzu, especially when combined with 2 to 3 yr of fallow, lowered the seedbank more than the leucaena and traditional bush fallow systems.
Open Access
Endangered Plants in Nigeria: Time for a New Paradigm for Vegetation Conservation
(2010) Isichei, Augustine O.
The global problem of biodiversity loss, especially vegetation loss has been of concern since humans realized the implications of habitat destruction in the course of economic development. Plants form the bedrock of life and human material culture depends on them. Our human world has been so closely tied to plants that it is difficult to imagine human existence without them. Being the only primary producers, all other consumers in the food chain are dependent on plants for food, fibre and energy. Knowledge of plants, their habitats, structure, metabolism and inheritance is thus the basic foundation for human survival and the way a people incorporate plants into their cultural traditions, religions and even cosmologies reveals much about the people themselves.
Open Access
Mineral Nutrient Flow from an Inselberg in South-Western Nigeria
(1990) Isichei, Augustine O.; Morton, Alan J.; Ekeleme, Friday
In a study carried out to find out if inselbergs enrich their surroundings with nutrients via drainage, amounts of total nitrogen, nitrate-nitrogen and potassium in rainfall, drainage from bare rock patches and vegetation mats on an inselberg in South-western Nigeria were measured over one year. 43.3 kg ha-1 total nitrogen, 4.8 kg ha-1 nitrate-nitrogen and 10.7 kg ha-' potassium were recorded in rainfall for the year of study. The amount of total nitrogen in drainage from bare rock was 79% of that in rainfall whilst that in drainage from vegetation mats was 29% of the rainfall amount. The respective values for nitrate-nitrogen were 57% and 13%; for potassium they were 90% and 38%. It was assumed that the loss of nutrients as water drains through vegetation mats and over bare patches was due to absorption by plants and soil in the mats and lichens in the bare patches. It was therefore concluded that there was no net enrichment of rainwater with nutrients as it flows over inselberg slopes. There is, however, a funneling of water along with contained nutrients from the inselberg to the surrounding areas. This funneling is additional to the nutrients and rainfall incident on these surrounding areas and may account for the vegetation around inselbergs being more lush than vegetation in the same area but further away from the inselbergs. A simple modeling approach was used to assess potential nutrient outflow from inselbergs. The model shows that discharge of nutrients from the edges of inselbergs increases linearly with inselberg diameter. The model further shows that if nutrient funneling only affects an area near to the edge of the inselberg then nutrient addition is several times higher than would be expected from rainfall deposition alone.
Open Access
Nigerian Man and Biosphere Research Plots in Guinea Savanna: Floristics and Structure of the Vegetation
(1991) Muoghalu, Joseph I.; Isichei, Augustine O.
A study was made of the vegetation of three plots used in the Nigerian Man and Biosphere Research Programme for Savanna Studies. The aim is to provide detailed information on the vegetation of the plots which may possibly contribute to an understanding of factors influencing savanna structure and relative abundances of forbs, grasses and woody species. Results show that there are differences in the species composition of the plots. There are more forb species than grass species in each plot. The woody basal areas and crown areas of the plots do not depend entirely on the density but also on the size of the woody species. There are differences in herbage yield in the plots that could be attributed to differences in soil properties, species composition and level of human and animal activities between the plots.
Open Access
Nitrogen Concentration in the Major Grasses of the Derived and Guinea Savanna Zones of Nigeria in Relation to Season and Site
(1983) Isichei, Augustine O.
The concentration of total Kjeldahl N in above- and below-ground grass samples was monitored at five Nigerian savanna sites over 3 years. Significant variation, even in the same species, was found from plot to plot, with the highest concentrations in the samples from early-burnt Derived savanna and the lowest from northern Guinea samples. This may be related to soil N concentrations as a significant positive relationship was found between soil and plant concentrations. Nitrogen concentration in above-ground grass biomass declined almost exponentially from flushing through the dry season, whereas below-ground N concentration increased with the approach of the dry season. Two shade-favouring grasses, Andropogon tectorum and Beckeropsis uniseto were found to have the highest N concentrations above-ground.
Open Access
Nitrogen in Savanna Grass and Litter
(1982) Isichei, Augustine O.
grasses are low in nitrogen. This is relayed to the low nitrogen content of the soils: there is decreasing nitrogen in the soil northwards and this is reflected in the grasses. Even in the same environment some species are better accumulators than others. Possible reasons are advanced for this. The Andropogon species and Beckeropsis uniseta are the best known accumulators. There is a well marked seasonality in nitrogen concentration in grass. The below-ground parts have their highest concentration in the dry season, while in the above-ground parts the highest concentration is at the beginning of growth. Litter is important because it is a major means of nitrogen re-cycling. Its pattern of fall and decay in the savanna is discussed. It is emphasized that most of the litter fall is after the annual fires. Nitrogen content of litter varies from site to site but does not show significant seasonal difference.
Open Access
Nutrient Content and Performance of the Herbaceous Legume Tephrosia Bracteolata in Relation to the Grass Andropogon Tectorum in both Natural Habitat and Pot Culture in Southwestern Nigeria.
(International Society for Tropical Ecology, 1990) Isichei, Augustine O.; Awodoyin, Rasheed Olufemi
Tephrosia bracteoluta, an annual herbaceous legume (sub-family Papilioniodeae), occurs extensively in the savanna zone of West Africa. It is palatable to livestock. Its accumulation of nitrogen, phosphorus and potassium over a growing season (in natural habitat in Southwestern Nigeria) was measured and compared with that of Andropogon tectorum, another palatable grass in the same habitat. Crude protein concentration in Tephrosia throughout the growing season is enough to meet the recommended livestock requirements, whereas the concentration in Andropogon meets this requirement only when the grass is young. Tephrosia and Andropogon were positively associated in natural habitat Competition between Tephrosia and Andropogon in pot culture was investigated. Both species showed a decrease in yield with increasing density, a pattern also shown for number of tillers of Andropogon and girths and heights of both plants at maturity. In the mixture the yield port plant of Andropogon was higher than in its monoculture.
Open Access
Omo Biosphere Reserve, Current Status, Utilization of Biological Resources and Sustainable Management (Nigeria)
(UNESCO, 1995) Isichei, Augustine O.
Omo Biosphere Reserve, which derives its name from River Omo that traverses it, is located between latitudes 6o35' to 7 o 05' N and 4o 19' to 4o 40' E in the Ijebu area of Ogun State southwestern Nigeria. The Reserve was constituted in 1925 and covers about 130 500 hectares, about 20 km from the Atlantic coast in its southern most parts. Geologically the Reserve lies on crystalline rocks of the undifferentiated basement complex which in the southern parts is overlain by Eocene deposits of sand, clay and gravel. The terrain is undulating and the maximum elevation of 150m above sea level is towards the west which the lowest parts of the Reserve are in the south where the River Omo joins River Oni, the Reserve's eastern boundary, before flowing into the Lekki Peninsular on the Atlantic coast. There are swamps in the south especially near the junction of the two rivers. The soil is tropical ferruginous (Ferric luvisol, according to FAO nomenclature). The mean annual rainfall ranges from about 1600 to 2000 mm with two annual peaks in June and September, with November and February being the driest months. The Reserve is in the mixed moist semi-evergreen rainforest zone. The northern parts of the Reserve is relatively dry forest with typical species such as Sterculia rhinopetala while Nauclea diderrichii and Terminalia superba are common in the wetter central parts. In the wet forests on sandy swampy soils in the south Lophira and trees in the Meliaceae family are common. There is a 460 ha Strict Natural Reserve (SNR) which was established in 1946 as a inviolate plot but later designated an SNR, in the north central area of the Reserve. An elephant sanctuary has recently been created around the SNR. Around the sanctuary and the SNR is the 'open' area of the Reserve where experiments and other treatments are located. There are about eight enclaves some of the fairly large inhabited by farmers and hunters in the open area. There is also a sawmill and a Gmelina plantation. Timber from the Reserve and Gmelina logs from the plantation support the sawmill while the Gmelina is also exploited as raw material for the recently commissioned Iwopin Paper Mill by Lekki Peninsular. Farmers practice wildlife in the Reserve for meat and several non-timber forest products. The farmers practice the Taungya system of farming whereby they participate in forest plantation establishment by nurturing tree seedlings during cropping on land allocated by the Reserve administering authority. Omo Biosphere Reserve, along with other reserves in the Nigerian forest zone has been used for studies on tropical moist forest regeneration with emphasis on 'economic' species and has since 1978 being the focus of the activities of the Nigerian Man and Biosphere (MAB), Theme One Project. Theme One is concerned with the 'Ecological effects of increasing human activities in tropical and sub-tropical forest ecosystem' and studies have been carried out on natural forest structure, plant and animal species composition, regeneration processes and response to treatments and human interference. There has been deep concern about the diminishing Nigerian forest estate and the rapid changes taking place in forest ecosystems including the socioeconomic activities of the people interacting with the changing forest landscape. The MAB studies have shown that conversion of natural forest to Gmelina plantation does not necessarily lead to total loss of biodiversity. Forest conversions are inevitable in the foreseeable future in view of current levels of wood demand and the issue of management of plantations for biodiversity sustenance deserves international research attention as non-timber forest products get more emphasis. Furthermore, the forestry sector is joining the emerging trend of privatization of management of natural resources. Already in Nigeria the benefits of private crop plantations are evident but the gestation period before private forests are harvestable has made private forests unattractive. Management of private and communal forests in a sustainable manner as opposed to subsistence farming should interest many tropical countries. Forest Reserves are locally controlled in Nigeria but the Strict Nature Reserves are managed by the forestry Research Institute of Nigeria (FRIN), Federal Government agency. There have been conflicts of interest arising from differences in perception of the roles of Reserves. This report discusses these conflicts in terms of biodiversity conservation and sustainable development. Recommendations are made on the management of Biosphere Reserves as exploitable economic resource on the one hand and as global life support systems on the other.
Open Access
Overcoming seed coat dormancy in Tephrosia bracteolata Perr..& Guill., a Fodder Legume of West African Savanna
(Ecological Society of Nigeria, 2000) Awodoyin, Rasheed O.; Ogunyemi, Sola; Isichei, Augustine O.
Haphazard field establishment due to impervious seed coat dormancy is peculiar to legumes. The effects of physical scarification (sand abrasion, clipping with scissors and pin piercing), exposure to concentrated sulphuric acid for 0, 10, 20, 30, 40 and 50 minutes. and exposure to boiling water for 0, 5, 30, 60, and 120 seconds on percentage germination and median germination time of Tephrosia bracteolata seeds were studied in Ibadan. The results showed that the three methods were effective in overcoming hard seed coat dormancy in T. bracteolata. Treatment means in all the pre-germination methods were significantly (P<0.001) different. The final percentage germination values were similar and best in 20 and 30 minutes acid exposure time, 5 seconds boiling water exposure time, and in scissors and pin piercing treatments of the physical scarification. The 20 and 30 minutes acid scarification had lowest median germination time of 0.9 days followed closely by 5 seconds boiling water scarification with 1.1 days. Overcoming the impervious seed coat dormancy in T. bracteolata will ensure its uniform seedling growth if utilised for fodder bank, grazing reserve and green manure establishment. Boiling water pre-germination treatment for 5 seconds may be adopted .for its little skill and low resource demand.
Open Access
Primary Production in the Savanna
(1982) Isichei, Augustine O.
It is emphasized that there is a dearth of information on primary production in the savanna in spite of savanna occupying nearly 80% of the West African land surface. Known values from the literature of annual primary production are presented. Values range from 150 to 1800g m-2. This range is not totally encompassing as primary production is strongly influenced by local conditions. The methods in use for measuring primary production are reviewed and their applicability to the savanna examined. The factors that affect primary production in the savanna are enumerated and discussed.
Open Access
Relationship of Woody Plants to Herbaceous Production in Nigerian Savanna
(1982) Sanford, William W.; Usman, Sugei; Obot, Emmanuel O.; Isichei, Augustine O.; Wari, Musa
Evidence is presented that a light, high tree canopy leads to greater production of grasses in the Nigerian Guinea savanna than either full exposure or dense canopy. Furthermore, some shading provides a microenvironment where such favoured species as the Andropogons replace such undesirable species as Schizachyrium sanguineum and Hyparrhenia species. The role of trees in open rangeland in relation to mineral cycling and soil maintenance is briefly discussed. It is recommended that the common practice of clearing all trees to improve rangeland is stopped and a low density of large trees, preferably legumes, be maintained.
Open Access
Responses of Savannas to Stress and Disturbance: the Beginning of Desertification
(Federal Ministry of Science and Technology, 1985) Isichei, Augustine O.; Ero, Isaac I.
Stress and disturbance may be natural or caused by man but usually from a combination of extreme values of environmental variables. Their prevalence in the Nigerian Savanna and effect on stability and resilience and, in a sense, desertification has been examined. The stress and disturbance identified include drought, wood cutting and land cultivation, herbivory, annual burning. It is concluded that annual burning does not constitute a destabilizing factor as such since it could be regarded as regular annual phenomenon to which the plant species are adapted, but mainly as a force that accentuates the effects of other destabilizing influences created through improper land use. Effort has been made to place different savanna systems into ranges of stability and resilience. Suggestions have been made for improving grazing system, controlling indiscriminate wood-cutting and ecologically sensitive farming systems. Drought control is distinctly impossible except through irrigation which is not yet extensively practised. Land use and vegetation mapping must be done on a local scale permitting the application of management tools to delineated land units. Parameters of description, evaluation and prediction vary according to land use; intensive or extensive, transformational or conservational. A scheme has been proposed for assessing the phenomena of stress, disturbance/perturbation and their relationship to stability and resilience in the savanna.
Open Access
The Role of Algae and Cyanobacteria in Arid Lands: a Review
(1990) Isichei, Augustine O.
Algae, cyanobacteria, and lichens occur in surface cryptogamic crusts, as free-living organisms in water bodies and within or on rocks in arid lands. The possible roles algae, cyanobacteria, and lichens could play in arid environments include physical improvement and protection of the soil, contribution of nitrogen to the arid ecosystem by nitrogen-fixing cyanobacteria and lichens, and primary biomass production for use as food and other secondary production. Physical improvement and protection of arid soils has potential in controlling desertification and rehabilitating arid lands. Culturing algae and cyanobacteria for biomass production, already being utilized in nonarid environments in agriculture, acquaculture, and now in the biochemical industry, has bright prospects in arid areas with their abundant sunshine. Primary production by the organisms can also be used for direct human and livestock consumption and in urban waste treatment. Biomass production can thus act as a means of resource diversification and therefore relieve pressure on fragile arid lands.
Open Access
Species Profiles of Some Useful Plants in Omo Biosphere Reserve in Nigeria
(2006) Obioh, Gloria I. B.; Isichei, Augustine O.
Ecological ethnobotany was conducted in Omo Biosphere Reserve, Nigeria in order to elucidate the basic ecological and cultural variables needed for the conservation and restoration of some useful utilised in the reserve. Permanent sample plots of 25m and 25m each were laid out randomly in four sites in the reserve. Data on both vegetation and soil in each site were collected by random sampling method. Quantitative Ethnobotany was carried out using the Participatory Rural Appraisal (PRA) technique. The target species were Carpolobia lutea G. Don, Dioscoreophyllum cumminsii (Stapf) Diels, Irvingia gabonensis (Aubry-Lecomb ex O'Rorke) Baill., Myrianthus arboreus P. Beauv., Sphenocentrum jollyanum Pierre, Spondias mombin L. Tetrapleura tetraptera Taub. and Xylopia aethiopica (Dunal) A. Rich. The species were selected because they are indigenous, non-timber and highly utilised in ethnomedicine and nutrition. A total of 132 woody species in 39 families were identified. Most of the target species were found only in the transition zone in very low densities of about two to five per hectare. Spondias mombin was found only in cultivated areas. The target species tolerate moderately acidic soils; majority flowered in the dry season and fruited during the rainy season. They were harvested from the wild and used in the treatment of many ailments including malaria, yellow fever, worms, cough, infertility, gonorrhea and diabetes. The inclusion of some of the species in conservation and restoration program in the reserve is suggested.
Open Access
Specprof: a Tool for Biological Indexing
(Nigerian Conservation Foundation (NCF), 2007) Obioh, Gloria I. B.; Isichei, Augustine O.
The development of a comprehensive information base is one of the most compelling needs in conservation as it can contribute to coordinated conservation efforts. In biodiversity conservation, indexing of organisms is of great importance because it sets the stage for investigating their relationships to other organisms. In view of recent trends in information and communication technology, electronic archiving of available data on the species is needed as a primary step to biodiversity conservation. A species profile (SPECPROF) database, an electronic data archiving, vouchering and retrieval system has been developed to support plant diversity indexing in a wide range of ecosystems. SPECPROF is an application database developed in the Microsoft Windows environment. The fields in SPECPROF are structured using the Microsoft Access 2000 database programme with Visual Basic providing the Graphical User Interface front end. It allows users to input, query and display information available on species. It is a fast and easy conservation tool for use in biological indexing.
Open Access
Stocks of Nitrogen in Vegetation and Soil in West African Moist Savannas and Potential Effects of Climate Change and Land Use on these Stocks
(1995) Isichei, Augustine O.
Moist savannas which include undifferentiated moist woodlands and savannas with abundant Isoberlinia doka and I. tomentosa (also known as Sundanian woodlands and Guinea-Congolian secondary grassland and wooded grassland) extend across West Africa up to the Central African Republic. Nitrogen stocks in the standing woody vegetation, litter and soil as well as the amounts of nitrogen transferred between these stocks and that lost through savanna burning of woodland and open moist savanna types are presented. Most of the total nitrogen is in the soil and then in the woody vegetation, with the least amount in the herbaceous vegetation. In a global change scenario characterized by elevated carbon dioxide levels and increased temperatures, it is predicted that there may be a reduced grass abundance and an increased woody species cover. However, human induced land use changes usually drastically reduce woody plant numbers. It is therefore predicted that forbs and low shrubs may dominate the future vegetation of moist savannas. The implications of such vegetation changes on nitrogen stocks are discussed.
Open Access
Utilisation of Medicinal Plants and Its Implications for Conservation in Omo Biosphere Reserve, Nigeria
(2006) Obioh, Gloria I. B. (nee G. U. Ahuama); Illoh, Herbert C.; Isichei, Augustine O.
Biosphere Reserves are in situ conservation areas created to demonstrate the potential for conservation of biodiversity despite the growing human activities to support development. Currently, local options for forest management and for choice of conservable species have not been fully integrated into the management of biosphere reserves. Our paper aims at identifying the role indigenous knowledge could play in the sustainable management and conservation of biosphere reserves, using Omo Biosphere Reserve, Nigeria as a case study. We thus carried out ethnobotanical studies in the reserve following standard methods. We evaluated the local importance of eight medicinal plants and documented how they are used in the reserve. The species studied were Carpolobin lutea, Dioscorcophyllum cumminsii, Irvingin gabonensis, Myrinnthus arboreus, Sphenocentrum jollyanum, Spondias mombin, Tetrapleura tetraptera and Xylopia aethiopica. Our results show that rather than exotics, there are successful indigenous medicinal species in the biosphere reserve including Irvingia gabonensis, Sterculia rhinopetala and Tetrapleura tetraptera that could be used to support ongoing conservation programmes. These have high potential for maintaining the cultural and ecological resilience of degraded sites in the reserve. We recommend that the integration of local knowledge and practices into national and regional conservation programmes are critical in achieving the purpose for which biosphere reserves were established.
Open Access
Whatever Goes Up Must Come Down? The Environmental Consequences of Nutrient Cycling in Vegetation
(Obafemi Awolowo University Press., 2002) Isichei, Augustine O.
I studied plants individually or in groups and investigated how they interacted with their immediate environment and recycled energy and matter. I started my enquiry with attempts to understand how ecological phenomena operate in the Nigerian environment. I carried out my enquiries as a natural scientist with the hope that I can contribute to our understanding of the world around us and supply information to applied scientists for use in technological applications.