scholarly journals Diversity and Structure of an Arid Woodland in Southwest Angola, with Comparison to the Wider Miombo Ecoregion

Diversity ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 140 ◽  
Author(s):  
John L. Godlee ◽  
Francisco Maiato Gonçalves ◽  
José João Tchamba ◽  
Antonio Valter Chisingui ◽  
Jonathan Ilunga Muledi ◽  
...  

Seasonally dry woodlands are the dominant land cover across southern Africa. They are biodiverse, structurally complex, and important for ecosystem service provision. Species composition and structure vary across the region producing a diverse array of woodland types. The woodlands of the Huíla plateau in southwest Angola represent the extreme southwestern extent of the miombo ecoregion and are markedly drier than other woodlands within this ecoregion. They remain understudied, however, compared to woodlands further east in the miombo ecoregion. We aimed to elucidate further the tree diversity found within southwestern Angolan woodlands by conducting a plot-based study in Bicuar National Park, comparing tree species composition and woodland structure with similar plots in Tanzania, Mozambique, and the Democratic Republic of Congo. We found Bicuar National Park had comparatively low tree species diversity, but contained 27 tree species not found in other plots. Plots in Bicuar had low basal area, excepting plots dominated by Baikiaea plurijuga. In a comparison of plots in intact vegetation with areas previously disturbed by shifting-cultivation agriculture, we found species diversity was marginally higher in disturbed plots. Bicuar National Park remains an important woodland refuge in Angola, with an uncommon mosaic of woodland types within a small area. While we highlight wide variation in species composition and woodland structure across the miombo ecoregion, plot-based studies with more dense sampling across the ecoregion are clearly needed to more broadly understand regional variation in vegetation diversity, composition and structure.

2010 ◽  
Vol 3 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Jacob Godfrey Agea ◽  
Clement Akais Okia ◽  
Refaat Atalla Ahmed Abohassan ◽  
James Munga Kimondo ◽  
Susan B. Tumwebaze ◽  
...  

2013 ◽  
Vol 59 (No. 4) ◽  
pp. 159-168 ◽  
Author(s):  
F. Pastorella ◽  
A. Paletto

Stand structure and species diversity are two useful parameters to provide a synthetic measure of forest biodiversity. The stand structure is spatial distribution, mutual position, diameter and height differentiation of trees in a forest ecosystem and it highly influences habitat and species diversity. The forest stand and species diversity can be measured through indices that provide important information to better address silvicultural practices and forest management strategies in the short and long-term period. These indices can be combined in a composite index in order to evaluate the complex diversity at the stand level. The aim of the paper is to identify and to test a complex index (S-index) allowing to take into account both the tree species composition and the stand structure. S-index was applied in a case study in the north-east of Italy (Trentino province). The results show that the Norway spruce forests in Trentino province are characterized by a medium-low level of complexity (S-index is in a range between 0.14 and 0.46) due to a low tree species composition rather than to the stand structure (diametric differentiation and spatial distribution of trees).  


2020 ◽  
Vol 5 (1) ◽  
pp. 27
Author(s):  
Abir Dey ◽  
Aklima Akther

The study aimed to quantify and discuss the current condition of the tree species composition and natural regeneration of southeast parts of Bangladesh (Cox’s Bazar North Forest Division). A total of 121 stems having dbh ≥10cm and 3481 stems of regenerating tree species (dbh <10cm) per hectare were recorded. A large trees comprised of 17 species belonging to 10 families and 14 genera and 30 regenerating tree species belonging to 19 families and 27 genera have been found. The forests were highly non-uniform, with three or four species represented most of the stands. The values of diversity indices indicated limited plant diversity, which is dominated by two or three tree species. Stems of 10-30 cm dbh contributed almost 90% of the total stem density, whereas more than 80% of the total basal area still belonged to trees with dbh 100 cm or above. Dipterocarpus turbinatus was the most dominant species which have the highest Importance Value Index (IVI) with 135.82 and embodied 37.71% of the total stand density and 72.19% of total basal area. The study will provide scientific basis for the future implementation of forest conservation strategies in tropical forests of Southeast Asia, particularly in Bangladesh. This study may also pave the way to further research on regeneration potentials of the native species for conservation and enhancement of forests in future.


Author(s):  
Zaira Negrín ◽  
José Ramón Arévalo

Urbanization is one of the main causes of species extinction. Closely linked to urbanization are road systems, which are a source of biotic and abiotic effects on the surrounding landscape. The continued existence of these corridors results in enormous human activity (Forman & Alexander, 1998). In particular, roads sharply define and fragment forest ecosystems leading to changes in plant species composition and vegetation structure from road border to the surrounding interior. This paper assesses border effects on tree species richness and composition in the laurel forest of Anaga, Tenerife, Spain. Effects of anthropogenic corridors on vegetation differed among the study sites. Multivariate analysis revealed that species composition is more related to the sampling site than to the effect of the corridor, while for density, significant differences were found between the road border and forest interior but not as a regular pattern. This suggests that main corridor disturbances regarding tree basal area is limited to the immediate road edge in the laurel forest, while for species composition, no significant differences were found.


2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Mehraj Uddin ◽  
Faqrul Islam Chowdhury ◽  
Mohammed Kamal Hossain

Abstract. Uddin M, Chowdhury FI, Hossain MK. 2020. Assessment of tree species diversity, composition and structure of Medha Kachhapia National Park, Cox’s Bazar, Bangladesh. Asian J For 4: 15-21. Tree species diversity assessment is considered an essential task to design robust conservation action plans of Protected Areas (PAs). Numerous researches have assessed tree diversity of different PAs of Bangladesh but tree diversity of Medha Kachhapia National Park (MKNP) is still unknown due to lack of research initiatives. It hinders forest managers of this PA to plan and implement conservation actions successfully. To this end, the study carried out a systematic sampling to ascertain composition, distribution, and diversity of tree species available at MKNP of Bangladesh. Findings revealed that representation of tree diversity of MKNP was very poor. Only 10 tree species representing 6 families were identified. Besides, MKNP was dominated by different Dipterocarpus spp. especially with Dipterocarpus costatus. Dominance in height and diameter classes and high Important Value Index (133.94) of D. costatus indicated that the tree might possess a suitable habitat in MKNP to maintain optimum dispersal, development, and growth. However, recent plantation activities with exotic Acacia auriculiformis and intensified human-induced disturbances might hamper its habitat. Thus, to conserve the habitat of D. costatus and remaining forest resources of MKNP, reforestation efforts should be shifted from exotic to native tree species, and community anthropogenic disturbances should be minimized.


2021 ◽  
Vol 2 (1) ◽  
pp. 16-19
Author(s):  
Ibrahim Umar ◽  
Lamido Auwalu ◽  
Ali Zakari ◽  
Ibrahim Fatima ◽  
Yahaya Umar Kubura ◽  
...  

Ecotourism refers to travelling to relatively undisturbed or uncontaminated natural areas, such as protected areas, with the aim of studying, admiring, and enjoying the scenery and the faunal and floral composition along with its existing cultural aspects. This paper evaluated Tree species composition of Maladumba Lake and Forest Reserve, Bauchi-Nigeria for sustainable eco-tourism development. Wandering quarter method of vegetation analysis was employed for the study where five sampling sites were studied to determine species richness, percentage frequency, basal area, relative density, relative dominance, importance value indices, mean distance between trees, mean area of trees and number of individual stem per hectare of tree species encountered. Results obtained indicated total of eighteen different Tree species in the protected area with Mitragyna inermis (126732.9 cm), Adansonia digitata (31714.9 cm), Balanites aegyptiaca (29727.3 cm), and Piliostigma thonningii (28697.7 cm) as species with the highest basal area. While Funtumia elastica presented the highest frequency of occurrence (80%) followed by Acacia nilotica, Anogeissus leiocarpus, Balanites aegyptiaca and Cassia singueeana with 60% each. Relative densities of Mitragyna inermis (18.1%) stood as the highest, followed by Funtumia elastica (16.6%) and Balanites aegyptiaca (12.5%). Relative dominance suggested Mitragyna inermis (18.1%) with the highest value seconded by Adansoni digitata (12.4%) and Balanites aegyptiaca (11.7%). Mitragyna inermis (49.8) had the highest IVI followed by Balanites aegyptiaca (24.4) then Piliostigma thonningii (11.7). Very low values of mean distance between trees (6.9 m), mean area occupied by individual trees (47.6 m), and density of trees per hectare (210) suggested sparsely populated vegetation cover in the protected area. It was concluded that Maladumba Lake and Forest Reserve is under serious deforestation. As an Ecotourism attraction, serious reforestation program was recommended to salvage the situation before the whole protected lose its value.


2014 ◽  
Vol 3 (1) ◽  
pp. 10 ◽  
Author(s):  
Humphrey Igbinosa Aigbe ◽  
Godwin Ejakhe Omokhua

Tree species composition and diversity were assessed in Oban Forest Reserve. Three stage sampling procedure was used to collect data on tree parameters – diameter at breast height (dbh); diameters over bark at the base, middle and top; merchantable height and total height using a minimum dbh limit of ≥10 cm in the tertiary sample plots. A total of 808 trees were measured and 72 species identified in the study area. Stand level parameters were estimated and tree diversity assessed. Results indicate that an average number of stems encountered per hectare were 306. Population densities of individual tree species ranged from 1 to 22 ha-1. Population densities of species were poor. The basal area/ha estimated is 34.67m2 and the species richness index obtained was 10.605, which indicate high species richness. The value of Shannon’s Index (HI) is 3.795 which is quite high.The results show that the forest reserve is a well-stocked tropical rainforest in Nigeria. The relative richness of the forest reserve in terms of individual tree species does not correlate well with the abundance because the abundance of each of the species was quite low and density poor. While there is paucity of most species, Staudtia stipitata was the most abundant (22 tree/ha). The forest has reverted back to the turbulent agrading stage of the forest growth cycle. 


2016 ◽  
Vol 11 (3) ◽  
pp. 743-750
Author(s):  
K. A Sreejith ◽  
U. M Chandrashekara ◽  
T. K Nirmesh ◽  
V. B Sreekumar

Knema Phytosociological studies have been carried out in a Myristica swamp in Northern Kerala to reveal the composition and distribution pattern of different tree species. On the basis of IVI, the family Myristicaceae was dominant and the association is attenuata - Myristica malabarica -Holigarna arnottiana type. The species like Gymnacranthera canarica and Myristica fatua var. magnifica, which are believed to be the essential elements of Myristica swamps, are totally absent here. A total 403 individuals (gbh > 10.1 cm) were recorded with a basal area of 34.25 m2 ha-1 in 0.5 ha. area. Total number of species recorded was 28, which represent 21families in which Myristicaceae represents 48.18% of total IVI. Among two dominant species, Myristica malabarica prefer swampy area hence their number of individual shows decreasing trend when we move from the swamp while the second dominant species Knema attenuata showing a reverse trend and was completely absent in the first five quadrats where soil water content is too high. Species specific eco-physiological studies are required to understand the reasons for change in the distribution pattern of these dominant species.


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