Table 4 - uploaded by Samuel Olalekan Olajuyigbe
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Tropical rainforest is continuously threatened by timber exploitation and conversion to other land uses. In this study, tree species diversity and forest structure of Eda Forest Reserve in Ekiti State, Nigeria, were assessed using systematic line transect and purposive sampling techniques for plot demarcation and data collection. Two transects (200...
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Context 1
... index revealed that the primary forest was the most diverse (0.93), while secondary forest and encroached farmland had indices of 0.92 and 0.87, respectively (Table 4). Similarly, the Shannon Wiener index had the highest value for primary forest (3.22) when compared with secondary forest (3.14) and encroached farmland (2.51). ...
Context 2
... the Shannon Wiener index had the highest value for primary forest (3.22) when compared with secondary forest (3.14) and encroached farmland (2.51). The species evenness revealed that primary forest contained more species (0.88) than the other vegetation types (Table 4). Species richness (Margalef's index) revealed that primary forest was more endowed than other vegetation types with 39 species/ha, followed by secondary forest with 38 species/ha, while 19 species/ha occurred in encroached farmland. ...
Citations
... Hence, if anthropogenic activities are not controlled, they would lead to total degradation and deforestation of Nigeria's forest reserves (Asinwa et al., 2018;Khadijat et al., 2021). Some of the major causes of forest loss include indiscriminate tree harvesting, agricultural expansion and urbanization (Chakraborti et al., 2010;Olajuyigbe and Jeminiwa, 2018). The forest areas were drastically reduced while the non-forest areas increased. ...
The ability of Nigerian forest reserves to support livelihoods and provide ecosystem services such as improved primary healthcare, sustainable food production, income generation, and carbon sequestration to mitigate climate change impacts; is currently constrained by deforestation and other anthropogenic factors. Hence, a clear understanding of the underlining patterns and processes of forest cover loss is required to ensure that appropriate methods and approaches are developed to promote conservation in these forest reserves. This study assessed the pattern of forest cover change in five forest reserves (Gambari, Ijaiye, Lanlate, Opara, and Igangan) in Oyo State, southwest Nigeria over 30 years. Landsat Enhanced Thematic Mapper Plus (ETM+) and eight OLI satellite images were acquired from the United States Geological Survey and used to assess the forest cover loss for the years 1990, 2000, and 2020. There was a significant change in the vegetation cover of the forest reserves with decreases observed over the three decades. From 1990 to 2020, the reduction in forest cover ranged from 42.26% (Opara forest reserve) to 91.21% (Igangan forest reserve). This high rate of deforestation and forest degradation in Oyo State highlights the need for immediate conservation action. In addition, relevant stakeholders and policymakers must intensify efforts focused on the restoration and rehabilitation of degraded forest reserves in the state.
... Impact of forest conversions includes changes in soil, vegetation, hydrological functions, climate change and depletion of natural resources and biodiversity (Jenkins and Schaap, 2018). Halting anthropogenic activities such as timber harvesting, logging, agriculture and promotion of sustainable forestry management practices would contribute to the resilience of a secondary forest in biodiversity and other ecosystem services (Olajuyigbe and Jeminiwa, 2018). However, adequate monitoring, protection and sustainable management of a tropical secondary rainforest require a good knowledge of flora component, diversity and structure (Fang Zeh et al., 2019). ...
Secondary forests may act as buffer area and serve as reservoir for biotic components that are lost
from primary forest due to anthropogenic disturbances. This study investigated the floristic
composition, diversity and community structure of Cocoa Research Institute of Nigeria (CRIN), IdiAyunre, Ibadan, Nigeria. Twenty-five main plots (each 50 m × 50 m) were randomly mapped out to
enumerate tree species, five 10 m × 10 m sub-plots were systematically mapped out within each main
plot to enumerate shrubs and three quadrats (1 m × 1 m) were laid in each sub-plot to enumerate
herbaceous species in Wet Season (WS) and Dry Season (DS). Relative Importance Value (RIV), Taxa,
Individuals, Dominance, Shannon-Wiener, Equitability and Jaccard similarity index were determined. A
total of 181 plant species from 145 genera and 54 families which included 63 trees, 33 shrubs and 85
herbaceous species were enumerated. In wet season, Triplochiton scleroxylon, Lonchocarpus
griffonianus and Chromolaena odorata had the highest RIV while in dry season, Terminalia superba,
Lonchocarpus cyanescens and C. odorata were the highest for trees, shrubs and herbs, respectively.
Low dominance but high equitability and Shannon-Weiner values indicated inter-specificity among
trees, shrubs and herbs. It was only in herbs that Jaccard-similarity was less than 100% across
seasons. Resilience for keystone species conservation is possible due to flora species heterogeneity of
the study site.
Key words: Forest ecosystem, biodiversity, anthropogenic activities, relative importance value, ecosystem
services.
... These are forest reserves that are adequately policed by the local groups, taboos and hunters in order to conserve the biodiversity and the sanctity of the forest. The system of community-based forests is a process by which the local communities organize themselves with support from Federal or S t a t e g o v e r n m e n t o r n o n -g o v e r n m e n t organization in the management of forest resources for varying degree and satisfaction of the peoples' livelihood (Bankole 1998;Brosuis et al 1998;Olajuyigbe et al. 2018). Due to the ecosystem deliverables to the local communities in terms of indigenous access to the forest, herbs collections for health benefits, environmental conservation and economic development, local communities to support the establishment of community forests (Olajuyigbe and Jeminiwa 2018). ...
This study aimed at evaluating the potential of community-managed forests to sequestration carbon. Systematic line transect was employed in the laying of the plots. A total of 8 sample plots in each community-based forest were used and soil samples were taken from four soil depths for soil carbon determination. Non-destructive method was used in the estimation of volume, above-ground biomass, below-ground biomass and carbon stock. The result also revealed significant difference in tree volume, biomass and carbon stock between the two forests. Tree Biomass and carbon stock were significantly higher in Ogun Onire community forest (48173.07 kg/ha, 30.02 T/ha) than in the community herbal heritage forest (10.745.31 kg/ha, 6.07 T/ha). Soil organic carbon estimated for Ogun Onire community forest (126.59 Tg) was significantly higher than that of community herbal heritage forest (67.95 Tg). Higher tree volume, biomass and carbon stock obtained for Ogun Onire community forest could be traced to the stiffer conservation measure put in place by the community as compared to the community herbal heritage forest where traces of encroachment and cultivation of arable crops were found. For sustainable availability of forest resources in community herbal heritage forest, severe conservation measure is recommended.
... These are forest reserves that are adequately policed by the local groups, taboos and hunters in order to conserve the biodiversity and the sanctity of the forest. The system of community-based forests is a process by which the local communities organize themselves with support from Federal or S t a t e g o v e r n m e n t o r n o n -g o v e r n m e n t organization in the management of forest resources for varying degree and satisfaction of the peoples' livelihood (Bankole 1998;Brosuis et al 1998;Olajuyigbe et al. 2018). Due to the ecosystem deliverables to the local communities in terms of indigenous access to the forest, herbs collections for health benefits, environmental conservation and economic development, local communities to support the establishment of community forests (Olajuyigbe and Jeminiwa 2018). ...
This study aimed at evaluating the potential of community-managed forests to sequestration carbon. Systematic line transect was employed in the laying of the plots. A total of 8 sample plots in each community-based forest were used and soil samples were taken from four soil depths for soil carbon determination. Non-destructive method was used in the estimation of volume, above-ground biomass, below-ground biomass and carbon stock. The result also revealed significant difference in tree volume, biomass and carbon stock between the two forests. Tree Biomass and carbon stock were significantly higher in Ogun Onire community forest (48173.07 kg/ha, 30.02 T/ha) than in the community herbal heritage forest (10.745.31 kg/ha, 6.07 T/ha). Soil organic carbon estimated for Ogun Onire community forest (126.59 Tg) was significantly higher than that of community herbal heritage forest (67.95 Tg). Higher tree volume, biomass and carbon stock obtained for Ogun Onire community forest could be traced to the stiffer conservation measure put in place by the community as compared to the community herbal heritage forest where traces of encroachment and cultivation of arable crops were found. For sustainable availability of forest resources in community herbal heritage forest, severe conservation measure is recommended.
... This forest reserve is presently undergoing a lot of changes due to anthropogenic activities, especially logging and conversion of forest land to cocoa and plantain farms through encroachment [23]. Increase rate of human activities on primary forests has a result of illegal felling of trees and change in land use pattern contributed immensely to forest degradation [24]. The report of Olajuyigbe and Adaja (2014) recorded rapid population growth, clearance for agriculture, domestic use of wood and selective logging as major drivers of deforestation. ...
... Banda et al. (2006) and Munishi et al. (2011) found that management activities had significant influence on tree species growth characteristics, density and volume. Tree diameter distribution is an indication of how well the forest is regenerating and making use of site resources (Olajuyigbe and Jeminiwa, 2018). The inverse-J diameter distribution of trees in all the four sacred groves in this study is typical of natural tropical forest ecosystems (Onyekwelu et al., 2008) and an indication of good regeneration status and healthy forest ecosystem (Onyekwelu and Olusola, 2014;Sundarapandian and Subbiah, 2015). ...
... Fabaceae) of the tree species in the recreation centers investigated is in correlation with what has been reported within other tropical rainforest ecosystems. Previous studies on rainforest ecosystems in Nigeria have reported that Fabaceae is one of the most dominant family of tree species in such forests (Adekunle et al., 2013;Olajuyigbe and Adaja, 2014;Olusola and Oyeleke, 2015;Olajuyigbe and Jeminiwa, 2018;Olajuyigbe and Akwarandu, 2019). Even more, Agbelade et al. (2016a) recorded Fabaceae as the family that dominated the most in-urban and peri-urban areas of Abuja, which is noted as savanna and not rain forest. ...
... Biodiversity indices are produced to bring the diversity and abundance of the species in different habitats to alike scale for comparison and when the richness of the species is high, it shows that the diversity value is also high (IIRS, 2002). The Shannon Wiener diversity index (H') has been used for characterizing community diversity in tropical forest ecosystems in urban and rural settings (Onyekwelu et al., 2008;Agbelade et al., 2016b;Olajuyigbe and Jeminiwa, 2018;Olajuyigbe and Akwarandu, 2019). The trend of H' in the present study showed that Ibadan Polo Club (IPC) was the most diverse of the five recreation centers ibvestigated, followed by Ibadan Recreation Center (IRC), Agodi Gardens (AG), Ibadan Golf Club (IGC) and lastly by National Museum of Unity Ibadan (NMUI). ...
The present study assessed the trees species diversity and the benefits that arise from their presence in five selected recreation centers in the urban area of Ibadan: Agodi Gardens, Ibadan Recreation Club, National Museum of Unity, Ibadan Golf Club and Ibadan Polo Club. The selected areas were purposively chosen due to the presence of tree species in the urban landscape. Both primary and secondary data were used for the study. Agodi Garden had in total 537 individuals, 46 tree species within 25 families. Ibadan Recreation Club had the total number of 148 trees, whereas 32 species within 22 families were represented. National Museum of Unity had a total number of 770 trees, classified in 23 species within 17 families. Ibadan Polo Club had a total number of 97 trees, 20 species and 15 families were represented. Ibadan Golf Club had a total number of 915 trees, 31 species and 9 families. Fabaceae family had the highest occurrence in Ibadan Recreation Club, National Museum of Unity, Ibadan Golf Club and Ibadan Polo Club, while Verbenaceae was more represented in Agodi Gardens. The study has shown the high occurrence of invasive species in tropical environment based on their regeneration potential. Data collected on total number of tree species, frequency of occurrence and families were subjected to descriptive analysis. A semi-structured questionnaire was used to obtain information. These centers serve as ex-situ urban centers/parks that still maintain and conserve various tree species and are important resources for social, economic and educational use. Biodiversity indices were also analyzed and it can be concluded that the type of organization and the main activity of the centers strongly influence the species diversity. The trend of Shannon-Wiener diversity index (H') showed that Ibadan Polo Club was the most diverse. Despite the higher number of individual trees encountered in NMUI, the H' value was very low, indicating the dominance of a few tree species within the area. From EH values obtained in the study, it can be concluded that trees species are most evenly distributed in IPC, followed by IRC, AG, IGC and lastly by NUMI.
... The family dominance in the forest followed the pattern reported for other tropical rainforest ecosystems in Nigeria. Previous studies on rainforests ecosystems in Nigeria have reported that Fabaceae, Euphorbiaceae and Sterculiaceae are the most dominant families in such forests (Adekunle et al., 2013;Olajuyigbe and Adaja, 2014;Olajuyigbe and Jeminiwa, 2018). Fabaceae is the third largest plant family and also the most common in the tropical rainforest comprising trees, shrubs, lianas and herb species (Burnham and Johnson, 2004;Mahbubur-Rahman and Ismot-Ara-Parvin, 2014). ...
Watershed ecosystems are unique ecologies that provide services and functions that are critical for the sustenance of natural water bodies as well as people that depend on them. However, there is limited information on plant species composition and distribution in most watershed forests in Nigeria. The watershed forest surrounding Arinta waterfall in Ipole Iloro, is an area protected by local communities, but facing anthropogenic threats associated with increased patronage from tourists from within and outside Nigeria. This study determined the floristic composition and vegetation structure in the Arinta watershed forest, using a stratified sampling technique. Nine sample plots, each 20 m by 20 m, were laid along three horizontal strata from the river valley upwards at 456 m, 470 m and 489 m above sea level. Within each sample plot, all plant forms were identified and enumerated, while growth variables like diameter and total height were measured for tree species. The species diversity indices were determined for all tree species encountered. Ninety two plant species from 51 families were found in the watershed ecosystem. These included 48 trees, 12 shrubs, 12 lianas, 16 herbs, 1 grass and 3 fern species. Ceiba pentandra was the most dominant species with an Importance Value Index (IVI) of 43.54% while Chrysophyllum albidum was the least (IVI = 0.78%). Fabaceae family had the highest species representation (14.13%) in the plant population. Shannon Wiener diversity index was 3.28, while the species evenness was 0.85. Approximately 64% of the tree species population had heights <10 m, while only 0.2% had heights >30 m. Similarly, tree species in diameter class 1-10 cm had the highest population of 630 wildlings/saplings ha-1.. The high floristic composition indicated the need for the conservation of the watershed which provides both protective and productive functions for the environment as well as the local community.
