1,721,003 research outputs found
Seed pre-treatment and early growth performance of piliostigma thonningii (schum.) milne-redhead under nitrogen amendment in Old Oyo national Park, Nigeria
No full textSurvival of wildlife in protected areas is dependent on innate attributes and response of vegetation to climate change. Piliostigma thonningii holds promise for wildlife conservation in Old Oyo National Park, but its population is threatened by physical dormancy. There is dearth of information on long-term benefits of its seed pretreatment and early growth response to nitrogen fertilizer. This study assessed effects of acid scarification on germination and early growth of P. thonningii under different nitrogen application rates. Seeds harvested from three purposively selected seasonal wetlands in Old Oyo National Park (OONP) were treated with 1N H2SO4 at durations ranging from 0 – 120 minutes in three replicates. Germinated seeds were enumerated over a 14-day period. Top soils from the wetlands were randomly sampled using soil auger in three replicates for physical and chemical analyses, and for early growth study with Urea fertilizer at rates 0, 50 and 100 kg/ha in experimental pots in completely randomized design. Growth and dry matter were assessed using ANOVA at P.05. Germination commenced in control treatments at 14 days after plating (DAP) and was low (13.3%). Germination progressively increased in acid treatment. At 5 DAP for soaking for 30 minutes gave 46.67%; while it was 96.67% at 40 minutes at 14 DAP. Higher soaking times gave 100% germination by 14 DAP, but with low growth vigor. The response of P. thonningii to Urea application was significantly higher in number of leaves at 12 weeks than in other rates. Other growth parameters are not significantly different at all rates. The biomass yield of P. thonningii was 1.98 g 0.21and 2.6 g 0.36 root and shoot dry weights at 6 weeks after sowing (WAS); and 7.3 g 0.04 root and 6.4 g 0.95 shoot dry weights at 12 WAS. Piliostigma thonningii can restore and improve wildlife abundance to mitigate climate change effects in the Park
Phytosociology of the herbaceous flora of university of ibadan oil palm plantation, University of Ibadan, Ibadan, Southwest, Nigeria
Full text linkPlantation agriculture perturbs native flora of ecosystems. This impacts vegetation biodiversity, through species invasion and shift in weeds population dynamics. Oil palm plantations are common in tropical landscapes, and can cause long-term floristic changes. There is paucity of knowledge on inventory and potential impacts of the plantation on community structure of plants. This study investigated herbaceous flora diversity and phytosociology as indicators of appropriateness of management strategy in the University of Ibadan oil palm plantation. The study site is located in a lowland rainforest at the Teaching and Research Farm, University of Ibadan, Ibadan, Nigeria on 07°27`253`N latitude and longitude 03°53`427`E. A systematic sampling was employed to enumerate herbaceous flora of a hectare mega plot. The hectare was laid along 100 m transects at 10 m intervals, with 10 m separating each transect. Each transect was laid to cut across middle of 9 m x 9 m x 9 m plant spacing for oil palm. Data were collected on species composition, frequency and density for determination of relative importance value (RIV), species diversity, ordination and classification. The plantation consisted of 32 herbaceous species in 15 plant families. Commelina erecta had the highest RIV (12.621) while Alchornea cordifolia had the least (RIV=0.288). Diversity indices indicated high species richness (Simpson Index = 0.909) among enumerated species and species co-dominance (D = 0.091) Ordination biplots indicated three distinct vegetation structures (Secondary, wetland, dryland/fallow). Classification model showed Commelina erecta had widest coverage of 92% in distribution at the site followed by Commelina benghalensis at 88%. The Oil palm plantation is heterogeneous in species composition, and was not detrimentally invaded. Weeding regimes and other agronomic practices in the plantation should be ecologically integrated to conserve its native vegetation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Vegetation communities and floristic diversity of eleyele and dandaru wetland in Ibadan, Southwest, Nigeria
No full textWetlands are globally important biodiversity hotspots and are facing rapid loss in floristic diversity and major changes in the functioning of these ecosystems due to various anthropogenic activities. However, wetlands located in large cities in developing nations are often unattended despite major yet often subtle changes in the functioning of the ecosystems. Recognizing this, the study was conducted in two wetland ecosystems, Eleyele and Dandaru wetlands in Ibadan city, southwestern Nigeria, to assess, document and determine the degradation or otherwise of the diversity and stand distribution of herbaceous and wood flora of the wetlands. The study was carried out on the wetlands of Eleyele (Lat, 7O25148.38″N, Long, 3O51145.18″E; elevation of 200 m ASL) in 2012. Systematic survey was carried out to assess the herbaceous and woody (girth ≥ 10 cm) components of the wetlands following Kent (2012) and Cox (1990) methods. Forty – five plotless sampling points of fifteen 5 m line transects, and twenty–one 10 m ×10 m plots were used for the respective surveys. Species presence and densities were used to compute Relative Importance Values and Diversity Indices following Kent (2012), Hammer et al. (2001) and Hill (1994). Topsoil was collected from the top 0 – 15 cm with a soil auger, bulked and analysed following AOAC (1984) methods. The wetland of Dandaru had higher diversity and was in a better floristic and edaphic health than Eleyele Lake wetland. This study recommends that Eleyele Lake wetland should be protected from anthropogenic activities that may lead to the loss of species
Performance of senecio biafrae (oliv. & hiern) j. moore under varying light intensities and compost rates in Ibadan, Southwestern Nigeria
Full text linkSolanecio biafrae is an underutilized indigenous vegetable in southwest Nigeria. It is usually found in shades of other tree crops. This study investigated growth of S. biafrae as influenced by compost application under different light intensities in Ibadan, Southwest Nigeria. The pot study was conducted twice at the Crop Garden of the Department of Crop Protection and Environmental Biology, University of Ibadan. Four levels of light intensities were examined under multiple layers of nets: Growth under four test light intensities of unshaded natural light (0 net), and three levels of shades (1 net, 2 nets and 3 nets) assessed under four levels (0, 10, 15 and 20 g/pot) of compost (ratio 3:1 Tithonia-Poultry waste) in a randomized complete block design with light intensity as Blocks. Growth and yield data were analysed using analysis of variance and post-hoc tests conducted with Fisher's LSD at 5% probability. Lowest light intensity resulted in increased number of leaves, from 7.75 to 15.50 at 4 WAT and 7.78 to 18.50 at 6 WAT. Application of 20 g/pot compost resulted in higher number of leaves, number of nodes, vine height, vine diameter, root and shoot dry matter of S. biafrae under reduced light intensities. Low light intensity in combination with increased compost rates enhanced growth performance of S. biafrae. Cultivation of S. biafrae is recommended using of Tithonia diversifolia compost at the rate of 20g/5kg soil under low light intensity for optimum yield
Floristic response of herbaceous flora to Intensive cropping systems: A case of Ajibode-sasa arable agroecosystem, Ibadan, Southwest Nigeria
Full text linkAgriculture a most significant land use types which alter natural ecosystem dynamics. Arable farming exerts much pressure on plant biodiversity, especially when practiced intensively in urban centers. There is dearth of information on floristic changes due to intensive arable farming in urban agroecosystems in developing countries. The study therefore assessed floristic changes resulting from and intensive farming practices at Ajibode-Sasa agricultural landscape. Ajibode-Sasa agroecosystem is a complex mix of arable cropping system between latitude N07°28′, E003°53′ and longitude N07°28′, E003°54. Comparative floristic surveys were conducted in 2016 and 2020 using quadrats (1 m2) systematically laid on 18 Transects ranging from 50 – 250 m long. A total of 224 and 184 quadrats were laid in 2016 and 2020 respectively. Reduction in numbers of quadrats laid resulted from physical anthropogenic development after the 2016 survey. Species identification followed standard procedures, and quantitative occurrence data were collected for determination of species composition and computation of relative importance values (RIV) and diversity indices. Land-use changes over four years period was determined using Google earth and QGIS. Herbacous plant composition with 123 cumulative number of species in both years reduced from 98 species in 2016 to 85 species in 2020 species RIV of species ranged from 0.038 – 14.803. Tridax procumbens had the highest RIV (14.803) in 2016, while it was Acmella brachyglossa (13.248) 2020. Species richness and floral diversity was high with Shannon-Weiner Index (3.081 and 3.088) and Dominance (0.09388 and 0.08746) in 2016 and 2020 respectively. Intensive cultivation favoured introduction and spread of invasive species like Tridax procumbens and Tithonia diversifolia. Eight introduced and invasive species were newly enumerated in 2020, with a total of 38 herbaceous species no longer encountered in 2020. Concerted efforts should be made to conserve native flora on the agroecosystem through sustainable practices like crop rotation and short fallow
Woody flora diversity and carbon sequestration potential of university of ibadan teak plantation: a consideration for climate change mitigation in southwest nigeria
No full textIncrease in atmospheric C02 is largely attributable to forest loss and carbon emission activities. Ability of forest plantations to sequester carbon for climate change mitigation is central to climate change mitigation, thus the study investigated carbon sequestration capacity of University of Ibadan Teak Plantation. The plantation (0.305 km2) is situated in a rainforest zone in Ibadan, Nigeria on 7°27'25.18'N; 3°54 14.04' E and a meaneievation of 209 m above sea level. Systematic sampling of 63 plots, each measuring 225 m2 was conducted on trees of >5 m bole height, >10 cm girth at breast height. Plots were distributed at 25 m intervals along seven line transects laid at 85 m apart. Species identification, relative importance value (RIV), diversity, multivariate analyses and carbon sequestration capacity of the forest were determined using standard procedures. Eighteen tree species in 12 families were enumerated. Tectonagrandis had highest RIV (49.347) with high dominance in many plots. Evenness index was generally low (below 0.5). Ordination biplotsindicated a mixed plantation. The carbon stock in the plantation was low (19.768 kg/ha/annum) compared to a typical tropical rainforest (600 kg/ha/annum), indicating 3.295% of carbon sequestration efficiency (CSE). The CSE of the plantation was low. This low CSE could be enhanced with adequate stocking density and removal of anthropogenic disturbances
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