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The Vegetation of Africa. A Descriptive Memoir to Accompany the Unesco/AETFAT/UNSO Vegetation Map of Africa
... The population of the northern sector of the Léfini The taxonomic ordination adopted is APG IV (2016) and the nomenclature is in agreement with Lebrun andStork (1991-2015). The ecological parameters The classification adopted in this study is that of White (1979White ( , 1983 The definition of the different types of diasporas adopted is that given by Dansereau and Lems (1957) and taken up by Lebrun (1960 In the center of each plot, a 5 m × 5 m (25 m 2 ) plot was installed (Fig. 3). ...
... Phytogeographical data on the juvenile flora of Mpoh provide evidence that this forest facies in the northern Léfini sector belongs to the Guineo-Congolian endemism center. This observation is supported by the dominance of the Guinean-Congolese base element and the existence of more than 75% of the marker families of the regional Guinean-Congolese endemism center (White, 1983). This phytogeographical analysis highlights the floristic purity of the Mpoh forest (White, 1983). ...
... This observation is supported by the dominance of the Guinean-Congolese base element and the existence of more than 75% of the marker families of the regional Guinean-Congolese endemism center (White, 1983). This phytogeographical analysis highlights the floristic purity of the Mpoh forest (White, 1983). Although the Mpoh forest is totally anchored in the Sangha-River corridor, the intrusion of taxa from neighbouring regions has hardly affected its floristic composition. ...
The natural regeneration of prime timber species with high economic potential is studied in the Mpoh forest, in the northern sector of the Léfini reserve. Although a source of economic and self-subsistence for local residents, the natural regeneration of these forest ecosystems has received very little attention. The floristic inventory was carried out in three one-hectare quadrats, in which (i) the d 1.30 of ligneous plants 1 cm ≤ d 1.30 < 10 cm, d 1.30 ≥ 10 cm and seedlings ≥ 30 cm in height were counted and measured; (ii) the degree of canopy openness, litter thickness and herbaceous cover. The inventory reveals 1208 individuals for 36 species and 20 families, i.e., 118 seedlings of height ≥ 30 cm; 769 individuals of 1 cm ≤ d 1,30 < 10 cm and 321 of d 1,30 ≥ 10 cm. Structural parameters favor Petersianthus macrocarpus as dominant in the 1 cm ≤ d 1.30 < 10 cm and d 1.30 ≥ 10 cm diameter classes, in density (89 trees.ha-1) and basal area (7.137 m².ha-1). In contrast, Entandrophragma sp. dominates the seedling class (h ≥ 30 cm). The bioecological indices highlight a difference in the floristic composition of the compartments. Natural regeneration, dependent on light and litter thickness, is generally good. Depending on the socioeconomic value of taxa with difficult natural regeneration, intervention may be necessary.
... The present study is based on specimens at C (Fig. 1), ETH, and K as listed in the Appendix, on the literature reviews, and on field observations by the first author in Ethiopia during 1995-2005. Due to the scarcity of specimens, particularly of flowering and fruiting material, sterile North Eastern Tropical African material has also been identified, using the vegetative characters of Johnson and Murray (2018: 38-39, 126 The map in Fig. 3 was produced by superimposing our records of X. nilotica with DIVA-GIS on a simplified version of Frank White's vegetation map of Africa (White 1983), using a shapefile produced by ICRAF / World Agroforestry Centre at http://www.landscapesportal.org/ layers/geonode%3Aafrica_white. ...
... Wood much used by Anuak population (Woube 1995). Map of distribution in North Eastern Tropical Africa in Fig. 2; distribution imposed on part of the vegetation map of Africa by White (1983) in Fig 3; modelled potential distribution in Fig. 4B. ...
... In Fig. 3, the distribution of X. nilotica is shown on a simplified presentation of the vegetation types of White (1983). All records occur in a peripheral position to the large, swampy area (the Sudd) along the Nile (the core area of the Nile Basin with White's vegetations no. ...
Based on written records and specimens of the new species, Xylopia nilotica D. M. Johnson & N. A. Murray (2018), described from Uganda and west of the Nile in Sudan and South Sudan, we have mapped the species. We find that it also occurs east of the Nile in South Sudan and in western Ethiopia. Its habitats range from open rain forest to open woodland. Modelling the potential distribution of X. nilotica suggests that it occurs in the periphery of the upper Nile basin, but it is probably undercollected. The potential distributions of X. longipetala (a Guineo-Congolian species) and X. holtzii Engl. (an East African coastal species), distinct but previously considered conspecific with X. nilotica, only marginally overlap with that of X. nilotica, which is endemic to the countries Uganda, South Sudan, Sudan, and Ethiopia, apparently a unique pattern of endemism. The new information does not change the assessment of X. nilotica as Vulnerable (VU). Other species of Xylopia in North Eastern Tropical Africa are X. rubescens Oliver and X. thomsonii Oliver in the Equatoria region of South Sudan, and X. rubescens, X. staudtii Engl. & Diels, and X. aethiopica (Dunal) A. Rich. in Uganda. A record of X. aethiopica in Ethiopia is based on false label information on the only known specimen.
... The miombo woodland is the largest dry woodland formation in sub-Saharan Africa, with a spatial extent of approximately between 2.7 and 3.6 million km 2 , covering about 10 % of the continent (Ryan et al., 2016;Guan et al., 2014;White, 1983). Despite their significance for biodiversity (Mittermeier et al., 2003;White, 1983); carbon sink (Pelletier et al., 2018); and food, energy, and water nexus (Beilfuss, 2012;Campbell et al., 1996;, little attention has been paid to its hydrological functioning. ...
... The miombo woodland is the largest dry woodland formation in sub-Saharan Africa, with a spatial extent of approximately between 2.7 and 3.6 million km 2 , covering about 10 % of the continent (Ryan et al., 2016;Guan et al., 2014;White, 1983). Despite their significance for biodiversity (Mittermeier et al., 2003;White, 1983); carbon sink (Pelletier et al., 2018); and food, energy, and water nexus (Beilfuss, 2012;Campbell et al., 1996;, little attention has been paid to its hydrological functioning. The uniqueness of the interactions between plant phenology and climate in the miombo woodland has been highlighted (Tian et al., 2018;White 1983) and has been particularly demonstrated by Tian et al. (2018), Vinya et al. (2018), Fuller (1999, and White (1983). ...
... Despite their significance for biodiversity (Mittermeier et al., 2003;White, 1983); carbon sink (Pelletier et al., 2018); and food, energy, and water nexus (Beilfuss, 2012;Campbell et al., 1996;, little attention has been paid to its hydrological functioning. The uniqueness of the interactions between plant phenology and climate in the miombo woodland has been highlighted (Tian et al., 2018;White 1983) and has been particularly demonstrated by Tian et al. (2018), Vinya et al. (2018), Fuller (1999, and White (1983). Of particular importance is its control of leaf phenology (i.e. ...
The miombo woodland is the largest dry woodland formation in sub-Saharan Africa, covering an estimated area of 2.7–3.6 million km2. Compared to other global ecosystems, the miombo woodland demonstrates unique interactions between plant phenology and climate. For instance, it experiences an increase in the leaf area index (LAI) during the dry season. However, due to limited surface exchange observations in the miombo region, there is a lack of information regarding the effect of these properties on miombo woodland evaporation. It is crucial to have a better understanding of miombo evaporation for accurate hydrological and climate modelling in this region. Currently, the only available regional evaporation estimates are based on satellite data. However, the accuracy of these estimates is questionable due to the scarcity of field estimates with which to compare. Therefore, this study aims to compare the temporal dynamics and magnitudes of six satellite-based evaporation estimates – the Topography-driven Flux Exchange (FLEX-Topo) model, Global Land Evaporation Amsterdam Model (GLEAM), Moderate-Resolution Imaging Spectrometer (MODIS) MOD16 product, operational Simplified Surface Energy Balance (SSEBop) model, Thornthwaite–Mather climatic Water Balance (TerraClimate) dataset, and Water Productivity through Open access of Remotely sensed derived data (WaPOR) – during different phenophases in the miombo woodland of the Luangwa Basin, a representative river basin in southern Africa. The goal of this comparison is to determine if the temporal dynamics and magnitudes of the satellite-based evaporation estimates align with the documented feedback between miombo woodland and climate. In the absence of basin-scale field observations, actual evaporation estimates based on the multi-annual water balance (Ewb) are used for comparison. The results show significant discrepancies among the satellite-based evaporation estimates during the dormant and green-up and mid-green-up phenophases. These phenophases involve substantial changes in miombo species' canopy phenology, including the co-occurrence of leaf fall and leaf flush, as well as access to deeper moisture stocks to support leaf flush in preparation for the rainy season. The satellite-based evaporation estimates show the highest agreement during the senescence phenophase, which corresponds to the period of high temperature, high soil moisture, high leaf chlorophyll content, and highest LAI (i.e. late rainy season into the cool-dry season). In comparison to basin-scale actual evaporation, all six satellite-based evaporation estimates appear to underestimate evaporation. Satellite-based evaporation estimates do not accurately represent evaporation in this data-sparse region, which has a phenology and seasonality that significantly differ from the typical case in data-rich ground-truth locations. This may also be true for other locations with limited data coverage. Based on this study, it is crucial to conduct field-based observations of evaporation during different miombo species phenophases to improve satellite-based evaporation estimates in miombo woodlands.
... For the purposes of this review, the savanna belt of Africa was defined as all the countries stretching from Senegal to Tanzania (see Fig. 2). Rainfall varies from 400 -1500 mm/year with a 4 -8 months dry season and mean annual temperature ranges 18-28 • C [38]. This specific set of conditions has allowed a great biodiversity to flourish [27], with a remarkably high percentage of megafauna given the relatively low precipitation regimes [39]. ...
... This specific set of conditions has allowed a great biodiversity to flourish [27], with a remarkably high percentage of megafauna given the relatively low precipitation regimes [39]. The category of savannas can be further broken down, according to precipitation, into the dry parkland savannaotherwise known as the Sudanian savanna-and the moister woodland or Guinean savanna [38]. These two savanna belts stretch from the western Africa to East and Southern Africa [28]. ...
... These two savanna belts stretch from the western Africa to East and Southern Africa [28]. The Sudanian zone itself can be divided geographically into the true Sudanian zone and the Zambezian zones; the two have similar rainfall regimes, but the Zambezian zone is slightly cooler, has a higher species diversity and is characterized by the presence of dense bushland [38]. ...
... Miombo woodlands are characterised by the dominance of members of the leguminous (subfamily Deltoideae) tree genera Brachystegia (~20 spp.), Julbernardia (2 spp.) and Isoberlinia (1 sp.), typically over well-developed C4 grassy understoreys (White 1983;Frost 1996;Chidumayo 1997a;Timberlake and Chidumayo 2011;Ribeiro et al. 2020b). Although characterised as being generally floristically homogenous across their range, more floristically diverse (notably including many other legume tree species) and structurally better developed (e.g. ...
... Although characterised as being generally floristically homogenous across their range, more floristically diverse (notably including many other legume tree species) and structurally better developed (e.g. taller, higher biomass) miombo woodlands occur under higher rainfall conditions (White 1983;Frost 1996;Godlee et al. 2021), especially in Zambia (White 1983). By convention, miombo formations occurring under >1000 mm MAR conditions are described as Wet Miombo, and those occurring under lower (<1000 mm MAR) rainfall conditions as Dry Miombo (e.g. ...
... Although characterised as being generally floristically homogenous across their range, more floristically diverse (notably including many other legume tree species) and structurally better developed (e.g. taller, higher biomass) miombo woodlands occur under higher rainfall conditions (White 1983;Frost 1996;Godlee et al. 2021), especially in Zambia (White 1983). By convention, miombo formations occurring under >1000 mm MAR conditions are described as Wet Miombo, and those occurring under lower (<1000 mm MAR) rainfall conditions as Dry Miombo (e.g. ...
Background and aims. To assess development of a robust emissions accounting framework for expansive miombo woodland savannas covering ~2 million km 2 of southern Africa that typically are burnt under relatively severe late dry season (LDS) conditions. Methods. A detailed site-based study of fuel accumulation, combustion and greenhouse gas (GHG) emission factor parameters under early dry season (EDS) and LDS conditions along a central rainfall-productivity and associated miombo vegetation structural and floristics gradient, from lower rainfallsites in northern Botswana to higher rainfall sites in northern Zambia. Key results. Assembled field data inform core components of the proposed emissions reduction framework: fuel and combustion conditions sampled across the vegetation/productivity gradient can be represented by three defined Vegetation Fuel Types (VFTs); fuel accumulation, combustion and emissions parameters are presented for these. Applying this framework for an illustrative case, GHG emissions (t CO 2-e) from EDS fires were one-third to half those of LDS fires per unit area in eligible miombo VFTs. Conclusions. Our accounting framework supports undertaking EDS fire management to significantly reduce emissions and, realistically, burnt extent at landscape scales. We consider application of presented data to development of formal emissions abatement accounting methods, linkages with potential complementary woody biomass and soil organic carbon sequestration approaches, and necessary caveats concerning implementation issues.
... This floristic discontinuity matches to the High (i.e. N&W) and Low (S&E) division of Africa previously proposed by White (1983) and which tracks climatic and topographical variation. In the N&W savannas, the floristic gradient determined by rainfall was partitioned into the Sudanian (drier) and Guinean (wetter) clusters. ...
... In Africa, the vegetation formations located north of the Guineo-Congolian Region have been distinguished from those in the south (Droissart et al., 2018;Linder et al., 2005Linder et al., , 2012White, 1983). The identification of the major phytochoria of Africa was first proposed based on the distribution of Diospyros species (Ebenaceae, White, 1979). ...
... The phytochoria, delineated with White's expertise and a huge literature review, were later supported by data and statistical analyses (Denys, 1980;Droissart et al., 2018;Linder et al., 2005Linder et al., , 2012, although in the biogeographical regionalization of the whole sub-Saharan Africa of Linder et al. (2012), plant patterns were less distinct than those of other taxa. At the global scale, Olson et al. (2001) White (1983), have recently been revisited (Osborne et al., 2018) with functional traits but their distribution of dominant lineages relied on White's map. ...
Aim
In tropical Africa, savannas cover huge areas, have high plant species richness and are considered as a major natural resource for most countries. There is, however, little information available on their floristics and biogeography at the continental scale, despite the importance of such information for our understanding of the drivers of species diversity at various scales and for effective conservation and management. Here, we collated and analysed floristic data from across the continent in order to propose a biogeographical regionalization for African savannas.
Location
We collated floristic information (specifically woody species lists) for 298 samples of savanna vegetation across Africa, extending from 18° N to 33° S and from 17° W to 48° E.
Taxa
We focused on native woody species.
Methods
We used ordination and clustering to identify the floristic discontinuities and gradual transitions across African savannas. Floristic relationships, specificity and turnover, within and between floristic clusters, were analysed using a (dis‐)similarity‐based approach.
Results
We identified eight floristic clusters across African savannas which in turn were grouped into two larger macro‐units. Ordinations at species and genus levels showed a clear differentiation in woody species composition between the North/West macro‐unit and the South/East macro‐unit. This floristic discontinuity matches to the High (i.e. N&W) and Low (S&E) division of Africa previously proposed by White (1983) and which tracks climatic and topographical variation. In the N&W savannas, the floristic gradient determined by rainfall was partitioned into the Sudanian (drier) and Guinean (wetter) clusters. Within the highly heterogeneous S&E savannas and woodlands, six clusters were identified: Ugandan, Ethiopian, Mozambican, Zambezian, Namibian and South African.
Main conclusions
The proposed pan‐African classification of savannas and woodlands might assist the development of coordinated management and conservation policies.
... The carrying capacity in 1814 was estimated using White's (1983) classification of African vegetation types. These were divided into range and non-range, according to contemporary reports of elephants living in the vegetation type (Bryden 1903) and estimates of current elephant densities in the vegetation type (Burrill & Douglas-Hamilton 1987), from which densities at carrying capacity were inferred. ...
... Data for this period are sketchy due to the two World Wars. Parker (1979) gives import and export data for East African countries for the period 1925-1977, while White (1983) and rough estimates of densities. The forest density is based on Barnes (1989), the Highveld and Sahel densities on contemporary accounts of elephant abundance and data in Burrill & Douglas-Hamilton (1987), and the others on data in Burrill & Douglas-Hamilton (1987). ...
Over the last two hundred years the ecology of Africa has changed substantially. One of the best documented change is the decline of the continental population of the African elephant. Two major factors likely to have contributed to this are: the reductions in the carrying capacity for the species due to habitat change, and the hunting for ivory. The relative importance of habitat loss versus hunting in driving the population decline has been at issue for several years. This paper attempts to tease out the effects of the two factors on the elephant population over the last two centuries, and to discuss the likely effects of each for the future.
... The vegetation maps used in this analysis are the Vegetationmap4Africa van Breugel et al., 2015), a PNV map of eastern Africa-henceforth the V4A map-which is a deconstruction of the UNESCO vegetation map of Africa (White, 1983)henceforth the White map. The species occurring in forests for both these maps are based on information collected by the Forestry Departments from the reserves in the two countries, and forest areas were delineated by extrapolation beyond the reserve areas. ...
... We suggest that the large area covered by White's "mosaic" (see Figure 1, large gray area in Uganda) may be an area that has shifted to a nonforest state. This hypothesis was presented by the authors of the original vegetation map of Uganda (Langdale-Brown et al., 1964) and later by Hamilton (1974) and is probably the reason for White (1983) to describe the area as a mosaic-with Zoka forest as the northernmost point. Buechner and Dawkins (1961), Paterson (1991), Nangendo et al. (2006), andNangendo et al. (2010) demonstrated how the boundaries between forest and savannas have fluctuated under the influence of climate, fire, and the abundance of wild and domesticated grazers. ...
Forest and landscape restoration are increasingly popular nature‐based solutions to mitigate climate change and safeguard biodiversity. Restoration planning and monitoring implies that a reference ecosystem has been defined to which the restored site can be compared, but how to best select such reference? We tested three different potential natural vegetation (PNV) maps of the same areas in Kenya and Uganda for their utility as ecological references with independent data that were not used when those maps were made. These independent datasets included presence observations of woody species from 76 sites in forest reserves in Kenya and Uganda, and classification of surveyed species into a system that included “forest‐only” and “nonforest‐only” ecological types. Our tests show that (1) the three vegetation maps largely agree on the environmental envelopes/ranges within which forests occur. (2) There are large differences in how well the maps predict the presence of forest‐only species. (3) Two maps, based on empirical observations (V4A and White), predict forest types well, whereas the third, based on climate envelopes only (NS), performs poorly. (4) A large area in Uganda is potentially in one of two alternative stable states. We conclude that it is possible to evaluate the utility of PNV maps at a more detailed scale than the level of biome and ecoregion. This indicates that it is possible to map PNV at scales required for reference for restoration and management of forest vegetation. We recommend that empirically based maps of potential natural vegetation are used in restoration planning (biome and PNV maps based on climate envelopes alone may be unreliable tools) as a baseline model for predicting the distribution of reference ecosystems under current and future conditions. It could conveniently be done by deconstructing the existing biome maps, supported by rapid botanical surveys.
... This part of the WPRS has a vast inland catchment (Fig. 3) that can promote a stable ecosystem in the coastal plains during humid conditions. The area falls in White's (1983) Red Sea Coastal Desert zone with characteristic vegetation including Acacia tortilis, dwarf shrubs (genus Indigofera), karira (Capparis decidua) and desert bunchgrass of the genus Panicum (Kassas, 1957). Coral reef shelves, winding bays and localized sandy beaches characterize the coastal margin. ...
... Hominin occupation of the WPRS is expected to have been intimately connected with humid phases considering that the region is characterized by a dry and hot conditions for the majority of the year at present (White, 1983). Paleoclimatic data and models (Drake et al., 2011;Scerri et al., 2014;Timmermann and Friedrich, 2016) show that humid phases turned much of the Saharan belt and the WPRS into green savanna grassland and shrubland (Fig. 1A), which are regarded as the most preferred ecosystems by hominins during the Pleistocene (Zeller et al., 2023). ...
The paper examines recently reported Acheulean and Middle Stone Age archaeological occurrences in nearcoastal plains on the western periphery of the Red Sea (Sudanese coast) with the aim of illuminating the role of the region in hominin survival, and possibly as an out-of-Africa dispersal conduit. Using a Viewshed analysis in ArcGIS, the study sought to assess the extent to which the seashore may have been Avisible from the archaeology-bearing localities during conditions similar to the present or those more humid interglacial phases than today.
The purpose of the Viewshed analysis is to gauge the range of habitat-options hominins had on the wester periphery of the Red Sea. The result demonstrates that the seashore would have been visible from most of the archaeological sites. Thus, it is reasonable to surmise that the coastal margin may have remained an integral part of the space exploited by the hominins that inhabited the nearby inland plains. However, the observation cannot be regarded as attesting all the areas deemed visible were necessarily exploited by hominins. Overall, the
archaeological evidence from the study area broadens our understanding of the range of environments hominins
occupied in Africa prior to and during their expansion to Eurasia. A proximate goal of the paper is to drive archaeological research attention to near-coastal landscapes, as such places may provide a potent vantage point to assess hominin engagement with the seashore. I conclude with an appeal to the paleoanthropological community to expand field-centered research to the vast understudied regions of Africa so as to capture hominin
experiences across diverse ecosystems of the continent. Only then will we be able to discern hominin biogeographic range at different periods and theorize about the ecological drivers of our species’ success.
... The miombo woodlands of southern Africa harbour unique biodiversity and are a major terrestrial carbon store, in addition to providing a diverse array of provisioning ecosystem services (McNicol et al., 2018;Ribeiro et al., 2020;Ryan et al., 2016). In southern Africa, the miombo woodlands cover up to 1969,000 km 2 and are found in the southeastern Democratic Republic of Congo, Angola, Zambia, western and southern Tanzania, central and northern Mozambique, northern Zimbabwe and Malawi White, 1983). Small and large-scale agriculture, charcoal production and timber harvesting are recognised as the leading activities causing biomass loss in the miombo region (Dziba et al., 2020). ...
... In southern Africa, this extensive savanna woodland type covers up to 1969,000 km 2 and forms a transitional system between the closed rainforests in central Africa and open semi-arid and arid savannas of southern Africa (The SEOSAW Partnership, 2021). The miombo ecoregion supports~8500 plant species, 4600 of which are endemic White, 1983). ...
The highlands of southeast Angola are one of the world's largest intact formations of miombo woodland. Recent interest from conservation groups is increasing the possibility of a new protected area in this conflict-afflicted, remote region, contributing to the “30 × 30” target of the Global Biodiversity Framework. With the potential for a new protected area, it is important to quantify the extent and change of natural and anthropogenic land covers in the region, not least because of the close dependence of livelihoods on natural resources in the miombo. We developed a 1990–2020 land cover time series, analysing deforestation, canopy opening, canopy closure, and vegetation regrowth after disturbance. Regional woodland extent has remained roughly constant despite frequent transitions between dense and open woodlands. Canopy opening peaked post-civil war, potentially related to the resettlement of displaced people. Over 30 years, 61 % ± 2 % of canopy opening was offset by subsequent canopy closure, which peaked a decade after the war ended, indicating the resilience of miombo systems. A woodland resource-use frontier, consisting of deforestation and canopy opening, is evident in the north-west of the area, likely driven by urban demand for agricultural products, charcoal, timber and other wood-derived goods. A distinct “core” of dynamic woodland occupies 52 % of the study region, where there is no evidence that shifting cultivation and local livelihoods are a net cause of land cover change. We do not find evidence for extensive net woody encroachment, only 2 % of the study region is being encroached by woody vegetation. This canopy closure is associated with remoteness from anthropogenic pressures and biophysical drivers that facilitate woody vegetation growth. Policymakers and conservation managers can use these data to aid in locating and prioritising interventions to sustainably produce agricultural and wood fuel products to meet increasing urban demand. Additionally, supporting conditions for maintaining both biophysical processes and livelihoods in remote areas is crucial to achieving 30 × 30 equitably.
... Arabia (El-Juhany et al., 2008). Consequently, it has been noted that J. procera will not regenerate in its own shade and its presence as a forest tree is largely dependent on fire, either natural or man-made, which removes the deep layer of humus and exposes the soil mineral for seed germination, seedling growth and survival (Sharew, 1982;White, 1983;Orwa et al., 2009). ...
... The fifth pattern lacked all of the individuals except the highest DBH class (>42.5 cm). This pattern is an indicator of lack of regeneration and establishment of populations of a species after a major disturbance such as clear-cutting for agriculture, grazing land or settlement, leaving few mature individuals as shade trees (Friis, 1986) or a life history strategy where mother trees negatively influence the germination of seeds and establishment of seedlings under their canopies (White, 1983;Bin et al., 2012). This pattern has rarely been reported for tree species, namely Juniperus procera and Erythrina brucei in the highly disturbed forests of the DAF (Bekele, 1993;Tadele et al., 2013). ...
The study was undertaken with the general objective of investigating the composition, diversity and structure of six forest patches in northwestern Ethiopia. Vegetation data were collected from 154 sampling plots of each 400 m 2 (20 m × 20 m). Species frequency, density, basal area, dominance, importance value index and population structure of the forest patches were analyzed using descriptive statistical tools. Floristic diversity and evenness were computed using Shannon diversity and evenness indices, respectively. The variations of floristic richness, density and basal area among the forest patches was tested using One-Way ANOVA in PAST software Package. The results of the study revealed that the study area harbored 212 species (122 woody and 90 herbaceous) belonging to 169 genera and 79 families. The Shannon diversity index and evenness values of the study area were 3.7 and 0.8, respectively. The highest number of species were recorded in Khatasa forest, followed by Bradi, Askunabo, Ambiki, Kidamaja and Degera forests. The density, basal area and dominance of woody species were 2172.1 stems ha-1 , 41.2 m 2 ha-1 and 23.1 m 2 ha-1 , respectively. There were no significant variations of floristic richness, density and basal area among the forest patches. A number of tree species showed unhealthy population structure and were found to be at conservation risk. To reverse these changes, among other measures, undertaking restoration activities using locally threatened woody species is highly recommended.
... White dots are known sites with pottery finds (dark dots representing sites mentioned in the text). Green shading shows the modern extent of the equatorial rainforest (White, 1983). The purple dotted line shows the extent of the Congo Basin (Runge, 2001, 11), and grey shading the topography above 500 m ASL at Maluba is Batalimo on the Lobaye river (de Bayle des Hermens, 1969, 1971. ...
... Sites along the Ubangi show a white border, while other archaeological sites are demarcated as simple black dots. The green shading denotes the putative rainforest distribution during the 1st millennium BCE (dark green; Bremond et al., 2017;Maley et al., 2017) and today (light green; White, 1983) (Wotzka, 1995). Further upriver, near the mouth of the Lua river, the Batalimo-Maluba style is among the earlier potteries in the region. ...
The spread of pottery-producing communities into the Congo rainforest is commonly linked to demic diffusion, driven by the so-called “Bantu Expansion.” It is considered the primary linguistic, cultural, and demographic process in Holocene sub-Saharan Africa. A key region in the reconstruction of this process is the western Congo Basin. This paper presents, for the first time, a coherent picture of the archaeological settlement history in the western and northern Congo Basin, uncovered by fieldwork of the late 1980s along the rivers Ngoko, Sangha, Likwala-aux-Herbes, Ubangi, and Lua. Archaeological research of the River Reconnaissance Project, directed by Manfred K. H. Eggert from 1977 to 1987, produced a pottery sequence for the region. Archaeological features and findings uncovered during the project’s field campaigns in the northern and western Congo Basin have only recently been studied in detail. The present analysis provides the only reliable source for a reconstruction of the cultural dynamics within the region due to the lack of subsequent archaeological fieldwork. Archaeological data and the sequence of pottery styles within the western Congo Basin, along the Sangha river, cannot support the claim that this region, due to a climate-induced extension of savannas, played a unique role as a ‘‘corridor” within the expansion of putatively “Bantu” speaking groups during the latter half of the 1st millennium BCE.
... Eritrea may be divided into three phytogeographic zones: Sudanian, western lowland; Afromontane, highland; and Somalia-Masai, eastern lowland (White 1983). Further subdivisions into western lowland, western escarpment, central highland, eastern escarpment, and coastal lowland have been employed by Zinner et al. (2000). ...
An isolated elephant population of about 100 animals live in the border region of northwestern Ethiopia and southwestern Eritrea. During the October-February dry season these elephant migrate to Eritrea and return southward to Ethiopia at the beginning of the short wet season. (Hagos, et al. 2003: Shoshani, et al. 2004) During dry period the only natural occuring permanent open water may be the Setit (Tekezze) River which forms the border between the two countiries. This article, the third of a series, 'summarizes nine years of ecological data retrieved from tusks and three years of data from dead elephants'. Body measurements and pathological data were taken from 11 elephants which were found dead between 2002 and 2004: four had fallen into manmade water wells, two were killed by farmers, and 'five died form unknown causes although some exhibited pathological bones and teeth.' Table 1 reviews information on the recently dead elephants while Table 2 reviews data (lengths, circumferences, weight, etc) from the 31 tusks collected since 1993. The authors note their observations confirm that a healthy elephant population inhabits the southwestern region of Eritrea duirng the long dry season. However, over the past three years it has suffered a loss of about 5% per annum, and this loss is in part due to attempts to drink from manmade wells because of the lack of natural water sources. Recommends artificial water sites, constructed so that young elephants could access them easily, be installed 'along the path of elephant movement. Calls for the establishment of protected areas because as this population increases the conflict with the human populations will become greater and more contentious land use issues will arise.
... Further subdivisions into coastal lowland, eastern escarpment, central highland, western escarpment, and western lowland have been employed by Zinner et al. (2000). According to White (1983) the phytogeographic classification of Eritrea includes at least three regions: Somalia-Masai, Sudanian and Afromontane. The western lowland (including the Gash-Barka) is a part of the Sudanian phytogeographic region. ...
This article reviews the historic range of elephant in Eritrea, as gleaned from archaeological and literary sources, notes taxonomic knowledge, and provides recent field data on the presence and status of elephant in the Gash-Barka area in the south-west. The shrinking habitat in Eritrea is due to both human settlement and lack of water resources. Two recent ground surveys, December 2001 and January-February 2003, implemented by the fourth author, as well as regular low flying United Nations flights between Ethiopia and Eritrea provided invaluable information of Eritrea's southwestern region. The dense riverine forest composed mostly of doum palms makes observation from the air difficult. During the last ground survey (Jan-Feb 2003) 'All 83 elephants, young and adult, observed in various locations within the watersheds of the Gash and Setit Rivers appeared in good physical condition'.
... This study was carried out in the forest reserve of Ouémé Supérieur located in the Guineo-Sudanian ecozones (Adjanohoun, 1989;F. White, 1983). The forest is located between latitude 9 • 11' and 9 • 47' North and longitude 1 • 58' and 2 • 28' East ( Fig. 1). The climate is a dry tropical one (Peel et al., 2007) characterized by a long rainy season (from April to October) that alternes with a long dry season (from November to mid-April) Gnanglè et al., (2011)). The average mont ...
... For each pond surveyed, the number of species, genera and families of taxa was first determined according to the APG IV classification [15]. The morphological types and chorological distribution of each tree species surveyed were determined by referring to the major phytogeographical subdivisions [16] and the catalogue of vascular plants of Côte d'Ivoire [17]. These parameters gave us an overall idea of the qualitative diversity of the flora studied. ...
The riparian forest galleries of the ponds in the Comoé National Park (CNP) constitute microhabitats colonised by a specific plant and animal community. These plant formations are of great research interest. These initiatives could lead to efficient management of these biomes in the short, medium and long term. This study is part of an effort to make the most of plant resources in forest galleries. The aim of this study is to assess the diversity of riparian species in the ponds of the CNP. The information was collected using the surface survey method combined with the roving inventory method. The inventory identified 78 species divided into 63 genera and 30 families. The buffalo pond forest gallery has the highest species richness, with 39 species in 33 genera and 19 families. The study also showed that for trees with DBH ≥10 cm, the species Diospyros mespiliformis (25.89%), Mitragyna inermis (17.11%), Khaya senegalensis (12.27%), Piliostigma thonningii (11.65 %), Cola gigantean (11.16 %), Vitellaria paradoxa (10.90 %) and Zanthoxylum zanthoxyloides (10.84%)) are the most abundant in riparian pond formations. The Fabaceae and Rubiaceae families are the most represented in terms of number of species, demonstrating that the flora of the forest galleries in Comoé National Park is of major ecological interest.
... Distribution. Zambezian Regional Centre of endemism (White, 1983) in Tanzania. Biology. ...
A new species Sonitha niniae Prozorov & Aarvik sp. n. is described from a threatened ground water forest in Western Tanzania. It is compared with closely related Sonitha adedapo Friend et al., 2024; Sonitha bekombo Friend et al., 2024; Sonitha ekongo Friend et al., 2024; and Sonitha chocolatina Friend et al., 2024. Adults, genitalia and map with collecting sites are illustrated.
... In terms of biogeography, four major phytochoria with specific vegetation types can be broadly distinguished: (i) Sahelian savannah (S), (ii) Sudanian savannah (SZ), (iii) Guinea savannah (SG), (iv) Guineo-Congolian (GC) forest with closed semi-deciduous forests and evergreen forests (Fig. 1A). The African lowland rain forest has three regions, namely Congolia, Upper Guinea, and Lower Guinea, the latter two being separated by the Dahomey Gap (White 1983;Poorter et al. 2004;Leal 2004). The current forest range originated from the dry period in the region during the Quaternary, especially the Pleistocene and the Holocene (Salzmann and Hoelzmann 2005). ...
Background and aims- Climate change induces increasing temperatures and drought, with possible profound shifts in species' presence and distribution. Ecological niche models are widely used to assess plant species responses to climate change. However, such data are scarce for West Africa, particularly for vulnerable multipurpose species. This study focuses on modelling the ecological niche and the conservation status of the multipurpose tree Detarium senegalense to improve insights into its habitat suitability in West Africa under past, present, and future climatic conditions. This will provide an essential basis for setting up global management plans through efficient conservation and ecological restoration policies.
Material and methods- The potential distribution of D. senegalense under past, current, and future climate scenarios were assessed using four algorithms including generalized additive models (GAM), generalized linear models (GLM), random forest (RF), and Maximum Entropy (MaxEnt). We also assessed the shift direction of suitable habitats and the conservation status of the species based on IUCN criteria. Overall, 220 occurrences were combined with a set of five bioclimatic variables to run the models.
Key results- Models performed well with good values of AUC (0.92) and TSS (0.73). Isothermality (41.10%) and Precipitation of Wettest Month (21.50%) contributed most to the distribution of the species. The distribution of D. senegalense was relatively constant from the past to the present but could decrease in the next decades. In the future, only 17.70% and 13.98% of the areas were predicted to be suitable under respectively ssp245 and ssp585. In protected areas, the suitable areas under ssp245 were estimated at 21.01% with a decrease of 2.50% and 14.60% with a decrease of 8.61% under ssp585 by 2050. The direction of the distribution shifted to the southeast under future climate scenarios. The conservation status assessment of the species is Least Concern (LC).
Conclusion- This study improves our understanding of the past, present-day, and future distribution of the species and provides support to better manage the conservation of D. senegalense in West Africa.
... Terminalia leiocarpa (Combretaceae) is a fairly common tree species, the distribution of which extends from Senegal through Cameroon to Ethiopia [23]. The species is found in savannahs, dry forests, gallery forests, and equatorial forests [24]. It grows to a height of 15 to 18 m and a trunk diameter of up to 1 m. ...
Farmers continue to use medicinal plants, alone or in combination with veterinary medicines, to treat animal diseases, especially in developing countries. The study aimed to determine the effect of climatic zone and anthropic disturbance level on the diversity of the natural stand and structures of Morinda lucida Benth, Spondias mombin L., Terminalia leiocarpa (DC.) Baill, Crossopteryx febrifuga (Afzel. ex G. Don) Benth, and Vitex doniana Sweet, five plant species often used in ethnoveterinary medicine in Benin. A floristic inventory was conducted in 206 plots of 0.15 ha each, distributed across 6 forests/hunting areas as well as surrounding fields and fallow land. The data were analyzed using R software by calculating the importance value index and the population structural parameters (density, basal area, mean height, etc.). The results showed that the floristic composition of the habitats of the five target species varied by climatic zone and disturbance level. Morinda lucida, S. mombin, and V. doniana were available in stands undergoing heavy disturbance in the Guinean zone, whereas T. leiocarpa and C. febrifuga were more available in the Sudano-Guinean and Sudanian zones. Values of structural parameters of these species were higher in the Guinean zone than in the other two zones. Furthermore, the results of the diameter structure showed C-values ranging from 1 to 3.6, suggesting the predominance of young individuals. This suggests strong human pressure on the adults of studied plants. These results should be used to contribute to the sustainable use of these species. Recommendations are made for the sustainable use of these five species, especially T. leiocarpa and C. febrifuga, which were heavily exploited given their low availability in stands under high human disturbance.
... Twenty-one species of this forest are listed on the IUCN red list (2020). The high rate of endemism and the high percentage of species with special status leads to the conclusion that this forest has not lost its specificity and is well conserved (White, 1983). However, the degraded surface area comprising 32% (22% degraded forest, 9% cultivation space, and 1% habitat and bare soil) indicates that the forest's wealth is under threat from populations infiltrating it for the establishment of perennial crops, primarily cocoa. ...
The Yaya reserve, one of the biodiverse forests in Ivory Coast, faces significant threats from agricultural colonization, illegal logging, and demographic pressure, which could jeopardize its sustainability. This paper focuses on contributing to the reserve’s sustainable management. To achieve this, three categories of data were collected: remote sensing data, floristic inventory data, and survey data from the neighboring populations. Remote sensing data were obtained by downloading images from the USGS earth explorer website. Floristic data were obtained through surface and itinerant survey. Survey data were collected using a structured interview. The images were processed to calculate the areas of various land use classes. The floristic data were analyzed for species richness and composition, while the survey data were analyzed to understand local perceptions of landscape dynamics, current management practices, and proposals for participatory management. The results revealed two major periods in the forest’s dynamics: increased deforestation from 1986 to 2005 and subsequent restoration from 2005 to 2022. These phases of degradation and restoration are likely related to recent social and political crises and management challenges. The floristic inventory identified 167 woody species across 134 genera and 47 families. 24 species (14% of the total) are endemic to West Africa, and 21 species (12.42%) are listed on the IUCN red list, indicating a relatively good conservation of the forest. The survey data highlighted the vulnerability of the forest and underscored the importance of centralized decision-making in management. The study suggests that participatory management could be a viable alternative for protecting the reserve. The hypotheses clearly states that the active involvement of local populations in the sustainable exploitation of forest resources can improve living standards, while helping to preserve the forest from exploitative practices.
... . La diversité de ces groupements végétaux a été également évaluée à travers le calcul des indices de diversité de Shannon-Weaver et d'Equitabilité de Piélou comme dans le cas de la diversité faunique. En plus de ces analyses, un calcul des spectres des types biologiques[31] et phytogéographiques[32] a été fait en vue d'analyser la répartition des espèces en fonction de leur mode de vie et de leur aire géographique à l'échelle mondiale. Enfin, la densité moyenne de tige, le diamètre de l'arbre moyen, la surface terrière et la hauteur de Lorey ont été calculés en tenant compte des paramètres dendrométriques collectés.Sedjro Gilles Armel NAGO et al.La densité moyenne de tige a été déterminée par le nombre de pieds d'arbres à l'hectare dans chaque groupement suivant la Formule 4 : ...
La régénération, la recolonisation et la conservation des écosystèmes dégradés
sont des défis contemporains des gestionnaires d’aires protégées avec la pression
anthropique ambiante. Le présent travail vise à fournir des données techniques
d’une recolonisation durable de la forêt classée de Pénéssoulou par la faune
mammalienne. Un dénombrement suivant la méthode du transect linéaire, des
relevés phytosociologiques au sein de 30 placettes installées et une enquête basée
sur la méthode de boule de neige ont été faits pour atteindre les objectifs de l’étude.
Le dénombrement de la faune a permis d’identifier 13 espèces au sein de la forêt
avec une dominance des Bovideae. Les relevés phytosociologiques effectués,
quant à eux ont montré à partir de la carte factorielle et du dendrogramme que
deux groupements végétaux caractérisent l’habitat de cette faune. Il s’agit
notamment du groupement à Parinari curatellifolia et Imperata cylindrica
caractérisant les savanes et du groupement à Elaeis guineensis et Burnatia
enneandra caractérisant les galeries forestières. Enfin, l’enquête effectuée auprès
de 57 individus révèle que l’amélioration de la sécurisation, la quiétude et la
qualité de l'habitat, ainsi que la réduction des activités anthropiques sont les
principaux facteurs responsables de la recolonisation. Pour maintenir durablement
la faune au sein de cette forêt, il urge de créer des mares, renforcer la sécurité
autour de la forêt et mener des activités de sensibilisation afin de limiter les
pressions puis enfin planifier des activités de suivi écologique de la faune.
Mots-clés : recolonisation, mammifères, conservation, habitat, distribution.
... Habitat categories were based on field data and the scientific literature regarding dominant woody vegetation genera in RWS (Fenner 1982;White 1983; The National Forest Reference Level for REDD+ 2020). We identified four main categories of habitat type: Commiphora/Lannea woodland; Vachellia/Grewia/Lannea shrubland; mixed Commiphora/Vachellia/Grewia/Lannea; and savanna (Supplemental Data). ...
... That Afrothismia ugandensis has been considered a variety of A. winkleri is unsurprising given their overall similarities and they may well share a recent common ancestor. The Budongo forest is considered amongst the easternmost examples of the Congolian phytogeographic domain (White 1983). Until recent geological times, the forest habitat of Afrothismia extended continuously across the Congo basin to the Cameroon home of A. winkleri, but this forest was only intermittently present in much of the Pleistocene, being replaced with grasslands in colder and drier periods (Kingdon 1989;Maley 2001). ...
The fully mycotrophic (or mycoheterophic) Afrothismia ugandensis Cheek nom. nov. (Afrothismiaceae), formerly described as A. winkleri (Engl.) Schltr. var . budongensis Cowley from the Budongo Forest in Western Uganda, is renamed, redescribed and illustrated. This change in status is supported by eight newly elucidated, qualitative, morphological, diagnostic characters despite the overall similarity with A. winkleri, a species restricted to Cameroon and Gabon. Afrothismia ugandensis is remarkable in the genus for occurring in semi-deciduous (not evergreen) forest and for having ellipsoid or ovoid (vs globose) root bulbils. It has only been recorded twice, first in August 1940, and most recently in June 1998, despite targeted searches in recent years. In both 1940 and 1998, only single individuals appear to have been detected. A single site for the species is known with certainty. It is here assessed as Critically Endangered [CR B2ab(iii); D1] using the IUCN categories and criteria. A. ugandensis is threatened by forest degradation and clearance due to illegal, selective, small-holder logging for firewood and charcoal, timber and limited agriculture.
... The de nition of forest given in two important studies of East-African vegetation [6,7] has been adapted: "Forest is a continuous stand of woody individuals, at least 5 m in height, with crowns touching or intermingling". ...
Tigray is one of the most environmentally degraded regions in Ethiopia left with remnant natural vegetation. The purpose of this study was to assess the plant communities of Embahasti remnant forest in southern Tigray, Ethiopia. Vegetation data were collected from 40 sample quadrates placed in transect lines, which were systematically laid. All vascular plant species including herbs, shrubs, lianas, and trees in each quadrat were recorded. Hierarchical cluster analysis and Canonical Correspondence analysis (CCA) performed that used for plant community analysis. Shannon-Wiener diversity Index was also computed for ecological data analysis. All the above analysis was performed using R 3.4.1 version software. A total of 74 plant species belonging 44 families were found in the study area; shrubs and trees (70.27%) species were dominant. Solanaceae, Fabaceae and Lamiaceae were the dominant families in terms of species. Three plant communities identified from the forest, namely Olea europaea subsp. Cuspidata – Juniperus procera, Myrsine africana – Erica arborea, Acacia abyssinica – Dodonea angustifolia . The highest Shannon-wiener diversity index was 3.26 while the least was 2.29 found in community one and three, respectively. Altitude, Slope, Grazing and human impacts are the factors influencing species distribution. It is, therefore, based on the results of this study, detailed ecological studies in relation to various environmental factors such as soil type and properties, ethnobotanical studies to explore indigenous knowledge on the diverse uses of plants, and sound management and monitoring as well as maintenance of biodiversity that promote sustainable use of the forest is recommended.
... The miombo regrowth vegetation regenerates more slowly than rain forest Aweto regrowth vegetation. This is because areas characterized by miombo vegetation have shallow stony soils (White 1983) and also experience comparatively low rainfall. The tree diameter class index yielded results that were strikingly different from those obtained using the mean tree diameter index. ...
Studies that relate the structure of tropical regrowth vegetation to soil properties are generally lacking in the literature. This study proposes three indices for assessing the structural regeneration of secondary forests. They are: (1) the tree diameter class, (2) the plant life form and (3) the woody/herbaceous plants ratio indices. They were applied to assess the regeneration status of forest regrowth vegetation (aged 1-10 years), derived savanna regrowth vegetation in south western Nigeria, and to secondary forests in different stages of succession in Columbia and Venezuela, Bolivia, Mexico in South and Central America and semi-arid savanna in Ethiopia and seasonal deciduous forest successional stages in India. In all the cases, the indices increased with increasing age of regrowth vegetation and hence, with increasing structural complexity of regenerating vegetation. The tree diameter class index increased from 32.1% in a 9-year secondary forest to 69.0% in an 80-year-old secondary forest in Columbia and Venezuela and from 0.4% in a 1-year fallow to 20.9% in 10-year regrowth vegetation in southwestern Nigeria. In semi-arid savanna in northern Ethiopia, the woody/herba-ceous plants ratio index increased from 18.1% in a 5-year protected grazing enclosure to 75.1% in 15-year protected enclosure, relative to the status of 20-year enclosure. The indices generally had correlations of 0.6-0.90 with species richness and Simpson's/Margalef's species diversity, implying that they are appropriate measures of ecosystem development over time. The proposed indices also had strong and positive correlations with soil organic carbon and nutrients. They are therefore, significant indicators of fertility status.
... Vegetation in and Benishangul Gumuz Region is part of Combretum-Terminalia Broadleaved Deciduous Woodland which extends from the foot hills of western escarpment of western Ethiopia to the cost of Senegal. 1 This vegetation in Ethiopia was first described by, 2 as the Broad-leaved deciduous woodland vegetation which was later described as Combretum-Terminalia Broadleaved Deciduous Woodland Ecosystem. 3,4 This ecosystem is dominated by the woody plant species such as Lannea fruticosa, Flueggea virosa, Grewia mollis, Pterocarpus lucens, Combretum collinum, Terminalia laxiflora and Stereospermum kunthianum; grasses such as Hyparrhenia rufa and Pennisetum thunbergii. ...
The organic carbon stock analysis was carried out in Broadleaf and Deciduous Forests of Benishangul Gumuz Regional State of Ethiopia with the following objective: determine carbon stock that would be found in Broadleaf and Deciduous Forests of Benishangul Gumuz Regional State (BGRS). The assessment was conducted from 22nd September to 22nd 0ctober 2017. A total of 101 flowering plant species were sampled in 35 sample plots. Three vegetation cover types were identified: Grassland, Open Woodland and Closed woodland. Among the different habitat types in the area; namely: Closed Wood Land (CWL), Open Wood Land (OWL), Grass Land (GL) and Bare Land (BL). The maximum mean Total Carbon Stock Density (TCSD) was recorded from closed wood land habitat with TCSD of 471 tons of carbon ha-1, followed by OWL, GL and BL with TCSD of 375.79, 118.75 and 47.92tons of carbon ha-1 respectively. Since the area is located in lower altitude with low amount of rainfall per year and fire prone area, the mean total above ground carbon stock density of the study area which is 134.94 tons of carbon ha-1 is very low as compared to the other forest types. The anthropogenic factors (the human influence) on the woody vegetation particularly the annual burning of the vegetation does not allow a chance for the accumulation of carbon in the soil.
... P. balsamifera s'adapte mieux sur le sommet de collines ou en pente, mais rarement dans les vallées (Kidikwadi et al., 2015). Le peuplement de P. balsamifera est lié à l'influence des caractères climatiques propres au milieu auquel elle est adaptée (White, 1983). Les travaux de Lubini (1997) et Doucet (2003 ont permis de classer P. balsamifera parmi les espèces des forêts climaciques. ...
Prioria balsamifera (Vermoesen) Breteler et Prioria oxyphylla (Harms) Breteler pré- sentent un grand intérêt sur le marché international de bois d’œuvre. Leur attrait commercial a exacerbé leur exploitation. Cet article présente la synthèse bibliogra- phique des connaissances relatives aux traits de vie de ces espèces afin de mettre en évidence les points sur lesquels les nouvelles recherches devront se focaliser. La revue de la littérature montre que peu d’études ont été réalisées sur ces espèces. Cependant, les données disponibles ren- seignent que P. balsamifera et P. oxyphylla ont une structure spatiale qui varie d’une région à une autre, allant d’une répartition aléatoire à une répartition agrégée, ce qui suggère que les facteurs exogènes auraient une influence sur leur structure. Chez P. balsamifera, les évènements phénolo- giques (défeuillaison, floraison et fructifi- cation) sont annuels et réguliers au niveau de l’espèce, mais irréguliers au niveau de l’individu. Les graines de P. balsamifera, stockées durant deux semaines, n’exigent pas de prétraitement avant semis et pré- sentent une durée de germination pouvant aller jusqu’à 3 mois et un faible pouvoir ger- minatif (45 %). Bien que sa croissance soit lente en plantation, P. balsamifera présente une meilleure croissance sous un ombrage moyen en forêt dégradée. Le tempérament semi-héliophile est admis pour ces deux espèces. Des investigations sur les facteurs déterminant la structure spatiale de ces espèces, leurs populations reproductrices, les paramètres régulant leurs floraisons, leurs fructifications, la dispersion de leurs diaspores ainsi que la dynamique de leurs cohortes juvéniles doivent être approfon- dies afin de proposer un modèle approprié pour leur gestion durable.
... La période d'exécution du PRRF s'étend de 1988 (Figure 1). Le climat est de type soudano-guinéen avec une saison pluvieuse et une saison sèche (White, 1983). Les précipitations moyennes annuelles avoisinent 1191 mm et la saison sèche s'étend sur cinq mois de novembre à mars (Trekpo, 2003). ...
Résumé
L’étude a consisté à identifier, à partir de la télédétection spatiale, les facteurs déterminant la conservation de la biodiversité végétale des forêts tropicales sèches dans un contexte d’aménagement forestier. Le modèle linéaire a été utilisé pour déterminer, dans la zone d’intervention du Projet de Restauration des Ressources Forestières (PRRF) de Bassila, l’effet du mode de propriété, de la taille
et de la localisation du couvert végétal, ainsi que l’effet de la période (pendant ou après le projet) sur l’évolution du taux de couverture des classes d’occupation du sol. Les résultats ont montré que le taux de couverture des forêts et des savanes diminuait significativement dans la période après le projet (respectivement F = 17,75 ; p = 0,000123 et F = 9,801 ; p = 0,003095). Le mode de propriété, la taille du couvert végétal et sa localisation n’avaient aucun effet significatif sur la conservation des forêts. Par conséquent, la période (pendant et après le projet) a été désignée comme déterminant la conservation de la biodiversité des forêts dans la zone d’intervention du PRRF. Néanmoins, d’autres facteurs tels que le coût élevé et la complexité des activités planifiées pour les gestionnaires locaux, le climat, la phytogéographie et l’urbanisation peuvent aussi impacter la conservation de la biodiversité des forêts tropicales sèches. Ainsi, l’étude doit être approfondie de sorte à prendre en compte d’autres facteurs
(coût élevé et complexité des activités planifiés pour les gestionnaires locaux, climat, phytogéographie, urbanisation, etc.) pour la conservation de la biodiversité des forêts en milieu tropical sec.
Mots clés : forêts tropicales sèches d’Afrique de l’Ouest, projets d’aménagement forestiers,
conservation de la biodiversité, télédétection spatiale, Bénin.
Plant biodiversity conservation determinants in the West Africa dry woodlands
Abstract
The study consisted of identifying, using spatial remote sensing, plant biodiversity conservation determinants of the West Africa woodlands in the management forests context. The linear model was used to determine, in the Bassila Forest Resources Restoration Project (PRRF) intervention zone, the effect of the mode of ownership, the size and location of the plant cover, as well as the effect of the period (during or after the project) on the evolution of land use classes coverage rate. The results showed that the coverage rate of forests and savannahs decreased significantly in the post-project period (respectively F = 17.75 ; p = 0.000123 and F = 9.801 ; p = 0.003095). The type of ownership, the size of the vegetation cover and its location had no significant effect on forest conservation. Therefore the period (during and after the project) is designed as determining the conservation of forest biodiversity in the PRRF intervention area. However, other factors such as the high cost and complexity of planned activities for the local managers, the climate, the phytogeography and the urbanization can also impact the biodiversity conservation of dry tropical forests. Thus the study must be extended to take into account the factors (cost and complexity of planned activities for the local managers, climate, phytogeography, urbanization, etc.) for the forest biodiversity conservation in a dry tropical environment.
Key words: West Africa woodlands, forest management projects, biodiversity conservation, spatial remote sensing, Bénin
... Two major vegetation zones can be distinguished in northern Benin: the zone of undifferentiated Sudanian woodland and the zone of Sudanian woodland (Natta, 2003;White, 1983). ...
In recent years, Hooded Vulture populations in West Africa have decreased substantially. However, in some areas within this region, the species is still relatively abundant. To find out more about the situation in West Africa, we assessed the status of Hooded Vultures in Benin, one of the countries where their status is not well known. We conducted road counts on paved and unpaved roads and along small trails over a total of 1451 km. We also conducted interviews with local abattoir watchmen, veterinarians, butchers and foresters to examine potential threats to this species. A total of 52 Hooded Vultures were counted mostly in the departments of Atacora (32) but also in Alibori (10) and Borgou (10). The relative abundance was four Hooded Vultures per 100 km, highlighting the near extirpation of this bird from Benin. A total of 49 interviews revealed that poaching for belief-based use (through shooting and traps) and decreasing food availability remain the most important threats for Hooded Vultures in northern Benin. If these threats are not mitigated, we predict the extirpation of the Hooded Vulture outside protected areas in Benin within the next two decades, possibly even sooner. Conservation measures, including awareness campaigns, and the improvement and enforcement of environmental legislation, must be urgently implemented to improve the protection of this Critically Endangered vulture species.
The present landscapes that define the tropical African region have evolved through the intricate interplay of climate and human interventions across various spatial and temporal scales. The late Holocene period is a valuable window for investigating how the environment responded to human influence. This study examined paleoenvironmental changes in the African tropics over the past 3500 years using proxy data, encompassing pollen, fungal spores, loss‐on‐ignition and microscopic charcoal extracted from core SS4 collected from Saiwa Swamp in western Kenya. The results show that Afromontane forests, represented by Podocarpus, Olea, Celtis and Juniperus , persisted in the region for much of the late Holocene despite prevailing conditions that favored the expansion of open savanna‐like vegetation and drought‐adapted taxa. The charcoal record reveals continuous fire occurrences throughout the sequence, raising questions about human‐induced fires and their potential role in shaping the landscape. The emergence of Sordaria fungal spores in the record between approximately 925 bce and 970 ce points to early human settlements engaging in livestock farming. Yet, these initial anthropogenic impacts did not trigger extensive forest clearing, hinting at a nuanced interplay between human activities and the environment during that era. The study emphasizes the importance of considering natural and human factors when interpreting environmental changes. It highlights the complex interplay of climatic, ecological and anthropogenic factors in shaping the landscape and vegetation dynamics over time.
Background Mammal-dispersed tropical trees can face regeneration problems due to increasing hunting pressure. We studied the case of Coula edulis Baill (Coulaceae), an African rainforest tree that produces the 'African walnut', an essential food and income resource for rural communities in Cameroon. We compared gene flow and regeneration dynamics in three populations with contrasting levels of human disturbance and mammal abundance. Using 21 nuclear microsatellite markers, we estimated the outcrossing rate and contemporary seed and pollen dispersal distances, and we analyzed the fine-scale spatial genetic structure (FSGS) to infer historical gene dispersal distances. Results Juveniles were outcrossed while 22–30% of the seeds were selfed, suggesting the elimination of inbred seeds. The mean dispersal distances were relatively short for seeds (105–219 m) and pollen (173–358 m), both shorter in the most intact forest. Immigration rates were three to four times higher for pollen (33–71%) than for seeds (7–28%), indicating some long-distance pollen dispersal. FSGS was strong in all populations ( Sp = 0.023–0.036), suggesting short-range historical gene dispersal distances consistent with contemporary estimates. We detected assortative mating, possibly due to higher flowering synchronicity between related individuals. The most disturbed plots had an inverted J-shaped trunk diameter structure, typical of continuous regeneration, while the intact forest had a complex diameter structure with a weak regeneration pulse. Conclusions Our results suggest that forest disturbance and mammal hunting do not significantly affect the dispersal distances of seed and pollen for Coula edulis , contrary to other mammals-dispersed trees. We hypothesize that the main dispersers are scatter hoarding rodents that are less impacted, or even facilitated, by hunting pressure. The species appears to regenerate better in disturbed forests, possibly due to a reduction in seed and seedling predators. However, natural populations are threatened by ongoing forest conversion into agriculture.
In recent years, satellite data have become available for free to the remote sensing community. Land use and land cover (LULC) changes are identified in remote sensing applications using Landsat satellite data. However, there is a lack of studies that utilize these data to assess the performance of satellite data on LULC classification and monitoring changes in complex landscapes. This study aims at evaluating LULC changes for the years 2013, 2018, and 2023 in the Sangha area using Landsat-8 OLI images. The Support Vector Machine (SVM) algorithm was implemented for detecting changes in the Sangha area. The results revealed that wetland forest and water bodies drastically declined, with a net change of −33.78 and-19.22%, respectively, while open forest, urban area, and bare soils with +77.91, +52.81, and +40.52% correspondingly substantially increased between 2013 and 2023. The overall accuracy and Kappa statistics achieved were above 91% and 0.85, respectively.
This study investigates the migration and settlement of the Ron people of Daffo on the Jos Plateau, using a mixed-method approach combining archaeological excavation, oral traditions, and radiocarbon dating. Focusing on the ancestral homes of Fier, Lankan, and Daffo, it explores cultural continuity from the 9th century AD to modern times. Findings show that the Ron are a hybrid population formed from early settlers and Chadic speakers from Kanem-Borno. Migration due to spatial contestation led to movement from Fier to Lankan and Daffo. Archaeological features across the sites include house foundations and ceremonial centres. Excavated materials, including pottery and smoking pipes, show strong cultural links between the three sites, with radiocarbon dating establishing settlement timelines from 9th-20th century AD.
We emphasise the urgent need to conserve the Ebo forest (Littoral Region, Cameroon), which holds 10 strict endemic plant species and 15 near endemics for a total of 25, a very high number far exceeding the threshold for its recent status as an Important Plant Area (IPA). We describe a further strict endemic species from the Ebo Forest, Memecylon ebo sp. nov. (Melastomataceae-Olisbeoideae), placed in sect. Afzeliana due to its ellipsoid, blue-green fruits. The yellow petals and jade green anther-connectives of M. ebo are unique in the genus Memecylon, which has >400 species ranging overall from Africa to the western Pacific. Memecylon ebo is assessed as Critically Endangered [CR], using the 2012 IUCN standard, due to its small range size and the extremely high and ongoing threats of logging at Ebo and also due to subsequent threats of potential oil palm plantation and mining projects. With the addition of Memecylon ebo, the tally of Critically Endangered plant species recorded from Ebo forest is now the highest of any IPA in Cameroon, equalling that of Ngovayang with 24 CR species.
The subtropical forests of southern Africa represent a remarkable vegetation and ecological anomaly in that they extend as far as latitude 34° S, well into the warm-temperate thermic zone. Their occurrence at these extreme southerly latitudes can be ascribed to the strong onshore influence of the warm Agulhas Current of the Indian Ocean. The Southern African Subtropical Rainforests in the southern half of Mozambique are a continuation of the tropical coastal forests further north along the Mozambique–Tanzania coast. Although they still can be classified as a member of the zonobiome E1 (Equatorial Zone; its subtropical global biome section), in Southern Africa, they acquire a transitional bioclimatic character through rainfall-depression becoming evident during the austral-winter season. In the study area, these forests are represented by two core regional biomes (Mozambique Tropical Lowland Forest and African Subtropical Coastal Forest) and three extrazonal (scarp) forest biomes, namely Tropical Scarp Forest, Subtropical Scarp Forest, and Albany Coastal Forest—all of the relict character.
The biomes of the zonobiome E2 Tropical Seasonal Zone occupy the largest portion of the tropical and subtropical regions of the world. This zone is also the dominant zonobiome of the studied MBSA. Physiognomically, the biomes of this zone are represented by savanna grasslands and woodlands, as well as Tropical Dry Forests (TDF). In bioclimatic terms, these biomes are characterised by alternation of prolonged dry and wet periods. In the study region we recognise Mesic and Arid Savanna at the rank of global biome, each comprising 25 and 9 regional biomes, respectively. While the savanna units are functionally underpinned by the domination of highly productive C4 grasslands, the TDF is characterised by an overall lack of grassy (or shrubby) understorey beneath a (semi)closed canopy of trees of predominantly low stature. There are two regional biomes of TDF recognised within the study area, namely Southern African Dry Forest and Southern African Dry Thicket. This chapter presents descriptions of all regional biomes of the zonobiome E2.
The Subtropical Alpine Zone is formed by two widely scattered archipelagos of small patches of ecosystems confined to habitats above the timberline, both in the Southern and Northern Hemisphere. In Southern Africa, it is limited to the highest elevations (above the climatic timberline) encountered in the Drakensberg/uKhahlamba massif, particularly in Lesotho and much less in South Africa. This biome is a well-studied high-elevation grassland containing a high number (and cover) of low shrubs, especially where disturbed by long-term grazing. Only one regional biome (DAG1 Drakensberg Alpine Grassland) falls within the continental biome Drakensberg Alpine Grassland.
The environmental history of parts of the Lagos lagoon during the Late Holocene was reconstructed based on the palynological analyses of a 51cm sediment core retrieved from Itokin, Lagos, Nigeria. Three phases (I-III) of environmental changes, beginning from 1480±30 BP, were recognized. The inferred environmental changes were characterized by the mangrove swamp forests, freshwater swamp forests, and open vegetation in varied proportions and accompanied by conditions that fluctuated between wet and dry climates. The pollen evidence reveals that the Itokin landscape has remained open since the last 1500 yrs BP, dominated by open vegetation and freshwater swamp elements. The mangrove swamp forest decreased at some point but recovered. In contrast, the rainforest remained low in occurrence throughout the core. The drivers of these environmental changes and their ecological implications are highlighted.
The palaeoclimate archives of tropical and marginal-tropical Africa and their interpretation are presented and critically discussed. The importance of the geomorphological, sedimentological, and pedological archives, in addition to Quaternary glaciations, for climate reconstruction is particularly emphasized and related to Quaternary marine environmental reconstructions. Quaternary climate and landscape change can be better reconstructed in Africa than in Latin America because (i) the African continent extends over 8000 km on either side of the equator to ca. 35° to the north and south, (ii) more than three-quarters of its area lie within the tropics (23.5° N and S), (iii) major mountain systems neither meridional (like the Andes of South America) nor latitudinal cross the continent, and (iv) the change from hot and humid tropical equatorial rainforest to the extremely arid desert is exemplary. The climatic and vegetation zones are interrupted in their latitudinal formation only in the mountains of East Africa. Early and middle Quaternary palaeoclimate archives (e.g. lake formations, moraines, speleothems, dunes) provide evidence of thermal and hygric climate fluctuations since the early Quaternary, which were much greater than the climate changes of the last glacial cycle. Cold phases are characterized by greater aridity in the lowlands. Warm phases (interglacials) were more humid; since Marine Isotope Stage 11, 400,000 years ago, warm-stage humidity decreased. The orbital and solar influence on large and small climate variations is documented by many different palaeoclimate archives. Terrestrial African palaeoclimate records document Arctic influence north of the equator and Antarctic influence in southern Africa. Climate modeling rarely considers the terrestrial palaeoclimate data of the African tropics. The extent to which climate influenced human cultures is shown using the example of the Sahara and East Africa.
This study investigated the physico-chemical variability of Alfisols with and without redox concentrations developed in sandstones within Dekina Local Government area of Kogi State, Nigeria. The research through reconnaissance identified two pedons at Okowowolo (Alf1) and Abocho (Alf2) with and without redoximorphic features. Soil profiles were dug using spade and digger, and interpreted following the standard of United States Department of Agriculture (USDA) for Field Description. Soil samples were collected in labelled polyethylene bags and core samplers for the physico-chemical analyses. Results revealed that the coarse and fine sand fractions were higher at the surface with respective mean values of 540 and 230 g kg-1 , than in the subsurface soils with mean values of 483 and 207 g kg-1. The silt proportion had a mean of 60 g kg-1 at the surface and a mean value of 70 g kg-1 in the subsurface soils. The clay proportion was lower at the surface soils with a range from 100 to 240 g kg-1 (mean: 170 g kg-1) than in the subsurface soils with a mean of 240 g kg-1. T-test revealed statistical significant difference with respect to coarse sand, silt and clay which have respective surface and subsurface p-values of 0.001, 0.012 and 0.001 at 95% confidence interval. The soils' cation exchange capacity percentage base saturation also indicated statistically significant difference among the soils with respective p-values of 0.005 and 0.039, at 95% confidence interval. The study concluded that alfisols in Kogi State have different physico-chemical properties that influence its fertility.
Analyses of archaeological fuel remains can provide insight into pyrotechnologies, resource management, and the local environment. In this paper, we examine archaeological charcoals from Hafit period (3300–2700 BC) levels in Building V at al‑Khashbah (al-Khashaba), Oman, to understand fuel harvesting and burning preferences associated with early copper production. Building V is currently thought to be the earliest identified copper-production site in Oman based on the presence of abundant pyrotechnological remains, copper slag, and stratified radiocarbon results. Here, we build on previous anthracological work reconstructing woodland composition from the site. Anthracologists are increasingly recognising that fuelwood collection is often based on social or functional grounds rather than species availability. To that end, we have combined traditional taxonomic analysis with the application of dendro-anthracological methods to examine how intensive wood harvesting was for copper production and whether it had effects on the local vegetation. Dendrological reconstruction of wood calibre and condition at burning combined with spatial patterning of remains provides a more nuanced view of these preferences than can be achieved through taxonomic analysis alone.
In this study, we reassess the phylogenetic relationships of the genus Sesamia Guenée, 1852 and examine in more detail the members of the nonagrioides species group, for which three distinct species complexes are identified. The calamistis subgroup comprises eight species, of which four new species are described: Sesamia kabirara Le Ru sp. nov. , Sesamia kalale Le Ru sp. nov. , Sesamia mapalense Le Ru sp. nov. and Sesamia teke Le Ru sp. nov. The incerta subgroup consists of 11 species, of which four new species are described: Sesamia kamba Le Ru sp. nov ., Sesamia lalaci Le Ru sp. nov. , Sesamia lusese Le Ru sp. nov. and Sesamia msowero Le Ru sp. nov. The nonagrioides subgroup comprises ten species of which two new species are described: Sesamia libode Le Ru sp. nov. and Sesamia satauensis Le Ru sp. nov. Phylogenetic and molecular species delimitation analyses of a multi-marker molecular dataset allow us to investigate and clarify the status of Sesamia species and species complexes. Our results yield a well-supported phylogenetic hypothesis for the genus, which supports the monophyletic nature of all but one species subgroup. The results of 16 distinct molecular species delimitation analyses show some levels of incongruence and, overall, a tendency towards over-splitting. We also present an updated list of species for the genus Sesamia and provide morphological keys based on male and female genitalia to determine the species group of any Sesamia species and to identify all species belonging to the nonagrioides species group.
Connaître les mesures classiques de la diversité floristique est crucial pour étayer les stratégies de conservation des ressources végétales des forêts dégradées. La présente étude vise premièrement à apprécier les paramètres de diversité spécifique et structurale de la flore ligneuse des îlots forestiers du massif montagneux de Lubero et deuxièmement, à déterminer son état de conservation afin de proposer des mesures appropriées pour sa gestion durable. Un échantillonnage stratifié par grappe a été effectué pour les inventaires forestiers. À cet effet, 297 placeaux de 50 m2 chacun ont été matérialisés dans dix îlots forestiers. Les indices de diversité spécifique ont été calculés et les paramètres dendrométriques ont été déterminés. L’entropie de Renyi a été calculée pour comparer la diversité alpha des espèces ligneuses entre les îlots forestiers. Le test rang de Kruskal-Wallis et l’analyse de variance ont permis de comparer les paramètres de diversité structurale entre les peuplements ligneux. Au total, 104 espèces ligneuses (86 genres et 45 familles) ont été recensées. La richesse spécifique des îlots forestiers varie entre 11 et 78. L’indice de diversité de Shannon-Wiener est très variable (1,98 à 4,03 bits) et l’équitabilité de Pielou est assez élevée (0,83 à 0,94). Des différences hautement significatives de densité (degré de liberté ddl=9, chi-square = 93.1316, P<0,0001), de diamètre moyen (ddl=9, statistique F =23.163, P<0,0001), de surface terrière (ddl=9, statistique F =53.568, P<0,0001) et de hauteur de Lorey moyenne (ddl=9, statistique F =208.454 ; P<0,0001) des espèces ligneuses ont été notées entre les îlots forestiers. Du point de vue de la conservation, 87 espèces ligneuses sont rapportées sur la liste rouge de l’Union internationale pour la conservation de la nature (UICN). Les espèces ligneuses déclarées « Vulnérables », « Quasi menacées » et « En danger » méritent une attention particulière des décideurs politiques et des gestionnaires forestiers.
This perspective addresses the nature of the past and current relationships between the ecological and biogeographical regionalization of plants and plant communities. It uses four examples (two related to continental scale and two related to regional/local scale) to document the cases of cross‐pollination between both approaches in the past and the need for concerted use of both ecological and distributional data in formulating robust regional spatial classification systems of biotic assemblages.
Premise of the study
Coula edulis Baill (Coulaceae) is a common tree species in the Guineo-Congolian forests producing an edible fruit known as African walnut, which is an important food and income resource for rural populations. However, the species suffers from a deficit of natural regeneration. We developed here nuclear microsatellite markers for C. edulis to be able to study the genetic structure of its natural populations and gene flow.
Methods and results
A genomic library was obtained using the Illumina platform, and 21 polymorphic microsatellite loci were developed. The polymorphic microsatellites displayed eight to 22 alleles per locus (average: 14.2), with a mean expected heterozygosity ranging from 0.33 to 0.72 in five populations from Central and West Africa.
Conclusions
The high polymorphism of the nuclear microsatellite markers developed makes them useful to investigate gene flow and the organization of genetic diversity in C. edulis, and to assess whether particular genetic resources require conservation efforts.
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