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1.
Riparian forests are classified as endangered ecosystems in general,particularly in sahelian countries like Burkina Faso because of human-induced alterations and civil engineering works.The modification of this important habitat is continuing,with little attention being paid to the ecological or human consequences of these changes.The objective of this study is to describe the variation of woody species diversity and dynamic in riparian forests on different type of watercourse banks along phytogeographical gradient in Burkina Faso.All woody species were systematically measured in 90 sample plots with sides of 50 m × 20 m.Density,dominance,frequency and species and family importance values were computed to characterize the species composition.Different diver-sity indices were calculated to examine the heterogeneity of riparian forests.A total of 196 species representing 139 genera and 51 families were recorded in the overall riparian forests.The species richness of individuals with dbh ≥ 5cm increased significantly from the North to the South along the phytogeographical gradient and varied significantly between the different types of riparian forests.Similarity in tree species composition between riparian forests was low,which indicates high beta diversity and reflects differences in habitat conditions and topography.The structural characteristics varied significantly along the phyto-geographical gradient and between the different types of riparian forests.The diameter class distribution of trees in all riparian forests showed a reverse "J" shaped curve except riparian forest of stream indicating vegetation dominated by juvenile individuals.Considering the ecological importance of riparian forest,there is a need to delineate and classify them along watercourses throughout the country. 相似文献
2.
Katharina Schumann Rüdiger Wittig Adjima Thiombiano Ute Becker Karen Hahn 《Biological conservation》2011,144(9):2369-2376
Non-timber forest products (NTFPs) strongly contribute to livelihood security in the semi-arid tropics. Main factors determining the populations of NTFP-providing species are human activities. This study examined the impact of land-use, combined with rates and patterns of debarking and chopping on a NTFP-providing tree (Anogeissus leiocarpa) in Burkina Faso. We compared stands in a protected area (W National Park) with those of its surrounding communal area (fallows, croplands) in order to (i) obtain an indication on the status of the population, (ii) assess its harvesting tolerance, (iii) estimate the sustainability of present management, and (iv) derive which additional management strategies may foster its conservation. Our results reveal that the stands of A. leiocarpa are in healthy states in fallows and in the park. In croplands, the absence of saplings gives evidence of a declining population. Nearly all individuals of A. leiocarpa were harvested in croplands and fallows, while the number of harvested individuals in the park was negligible. Intensity of debarking and chopping was tree size-specific. The sprouting ability significantly increased with higher chopping intensity. We conclude that despite the land-use impact and the intense harvesting, stands of A. leiocarpa are still well preserved due to the species life history (fast growing and high sprouting) and due to indirect positive influences of human activities by providing better environmental conditions for its recruitment. Thus, the population of A. leiocarpa is not at risk to over-harvesting and land-use even though it is not protected. 相似文献
3.
沿铺面道路和未铺面道路,调查了4种路边环境（缓变区,附近区,中间区和非缓变区）的Pteleopsis suberosa苗木种群结构和其更新机制。沿道路平行线调查了2m×5m的203块样方,记录每个样方内的种苗总数和每个种苗的活枝数。通过评价基部和水平枝芽和挖掘地下根系来确定更新机制。结果表明,在4种路边环境中,单一主干和多主干苗木的总密度及各自密度都有明显的变化（p〈0.05）。所有苗木都是无性繁殖而来,根出条占98%,眠芽蘖和萌生各占1%左右。研究表明,铺面道路和未铺面道路缓变区中等水平土壤的干扰可以刺激Pteleopsis suberosa根出条更新 道路类型（铺面和未铺面）对苗木密度没有影响,但对路边立地的P.suberosa种群的萌生能力来说,道路类型是一个重要变量。P.suberosa是一个耐干扰的物种,受道路网干扰后可以通过根出条繁殖。 相似文献
4.
Blandine Marie Ivette Nacoulma Anne Mette Lykke Salifou Traoré Brice Sinsin Adjima Thiombiano 《Agroforestry Systems》2017,91(3):565-576
In sub-Saharan Africa, extraction for daily livelihood needs often results in uncontrolled exploitation of bark and leaves of valuable medicinal and fodder trees. However, overharvesting of bark and foliage can reduce fruit production and threaten reproduction. This study evaluates the impact of combined bark and foliage harvesting on the performance of fruit production of Afzelia africana in Burkina Faso. We compared fruit and seed production at different harvesting intensities. Data on fruit yields were collected by stratified random sampling of 91 trees with no, low, severe, and very severe harvesting intensities. The fruit production varied with harvesting intensity, tree size and number of branches. Fruit and seed quantity and quality decreased with increasing harvesting intensity. However, no significant difference was detected between trees without and trees under low harvesting. Trees of all size classes under very severe harvesting intensity had no fruits. Under low harvesting impact, large trees had twice as many fruits as the control, whereas fruits were reduced by half to 95 % for the small trees. High harvesting intensity is an unsustainable practice that should be completely prohibited in order to ensure longterm persistence of Afzelia africana. Low harvesting intensity should be allowed, but only on large reproductive individuals. 相似文献
5.
T. K. Sop J. Oldeland U. Schmiedel I. Ouedraogo A. Thiombiano 《Land Degradation \u0026amp; Development》2011,22(6):519-529
In developing countries many people depend on woody resources for their livelihoods. Monitoring human impact on the populations of socio‐economically important species is therefore important for the conservation of vulnerable plants. In order to assess and compare the population structure and regeneration patterns of three multipurpose species, namely Acacia seyal Del., Balanites aegyptiaca Delile and Pterocarpus lucens Lepr. in four ethnic areas of the sub‐Sahel of Burkina Faso (Samo, Gourmantché, Fulani and Mossi), we used the size‐class distribution method (SCD) (Condit et al., 1998 ). Diameter at breast height (Dbh) of adult individuals of each species were sampled on 1000 m2 (20 m × 50 m) plots in each ethnic domain. Recorded Dbhs were distributed among eight size‐classes of 5 cm intervals. For each species, the slope of the regression of the SCD was considered to be an indicator of the population structure. Seedlings and saplings were recorded on five nested 25 m2 plots and fell into five height classes of 0·5 m intervals. The target species had significant (p < 0·001) negative SCD slopes with an inverse J‐shape distribution in all ethnic areas; indicating stable populations with good regeneration. Kruskal–Wallis test for the SCDs of A. seyal, B. aegyptiaca and P. lucens did not differ significantly among the ethnic areas (p > 0·1). This suggests that the dynamics of each of the three species is similar across ethnic domains and the sub‐Sahel. Data from P. lucens depicted an apparent stable population structure which contrasted with our field observations, perception of local people and previous studies. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
6.
Daniela H. Haarmeyer Katharina Schumann Markus Bernhardt-Römermann Rüdiger Wittig Adjima Thiombiano Karen Hahn 《Agroforestry Systems》2013,87(6):1363-1375
Non-timber forest products (NTFPs) are of high socio-economic value for rural people in West Africa. Main factors determining the status of the populations of socio-economically important tree species providing those NTFPs are human activities. This study assesses the impact of human population density, land use, and NTFP-harvesting (pruning and debarking) on population structure and fruit production of the socio-economically important tree Lannea microcarpa that is normally conserved by farmers on fields. We compared L. microcarpa stands of protected sites with those of their surrounding communal sites in two differently populated areas in Burkina Faso. Our results reveal an opposed land use impact on the population structure of L. microcarpa in the two areas. In the highly populated area, the species population was more stable in the protected site than in the communal site, while the opposite was observed for the less populated area. Trees of the communal sites bore more fruits than trees of the protected sites. Debarking and pruning had a negative impact on fruit production of the species. We conclude that low intensity of human impact is beneficial for the species and that indirect human impact facilitates fruit production of L. microcarpa. In contrast, in the densely populated area, human impact has reached an intensity that negatively affects the populations of L. microcarpa. While the extent of protecting L. microcarpa on fields still seems to be enough to guarantee the persistence of this important species in the less populated area, it is no longer sufficient in the densely populated area. 相似文献
7.
Tene Kwetche Sop Francois Wenemi Kagambèga Ronald Bellefontaine Ute Schmiedel Adjima Thiombiano 《Agroforestry Systems》2012,86(3):387-399
The aim of this study was to evaluate the effect of organic amendment on the germination and growth patterns of Jatropha curcas L. on completely barren and degraded land in the Sahelian area of Burkina Faso. Prior to the field trials, laboratory germination tests were undertaken to explore the impact of different pre-treatments on germination of Jatropha seeds. Seeds soaked in water for 24?h had the highest mean rate of germination (86%) while seeds that were pre-treated with sulphuric acid did not germinate. The results of the field experiment showed that plant growth and biomass development were significantly enhanced by organic amendment compared to the control. With direct seeding, 20% of the plants treated with organic manure survived after 2?years, while all seedlings of the control plot perished. In the plantations, 30% of the untreated seedlings remained alive whereas only 5% of the plants survived with amendment. The trials in unfenced plots were decimated by livestock grazing and trampling 2?months after the beginning of the experiment. This emphasizes the need to protect Jatropha plants at an early stage of their development from roaming animals. Organic amendment attracted humivorous termites, which were destructive to the seedlings. The use of pesticides may be necessary to control this problem. When directly seeded, plants of the control plots demonstrated poor growth and became rapidly diseased, further accelerating their decline. The low survival rates (5–30%) and meagre seedling performance, even for the amended plots, may be an indication that Jatropha is unsuited to severely degraded lands like the zippelé, and cannot be expected to give good yields and the claimed environmental and socio-economic benefits. However, we recommend that the performance of Jatropha on the zippelé should be further tested with other soil and water conservation techniques (half-moon, tillage, etc.) that have been shown to enhance crop production and yield on degraded lands in the Sahelo-Sudanian zone of West Africa. The impact of seed provenance on the outcome of this study is unknown. Therefore, further experiments should embrace seeds from different sources, including genotypes that are more adapted to dry conditions and might therefore show improved performance. 相似文献
8.
Fidèle Bognounou Mulualem Tigabu Patrice Savadogo Adjima Thiombiano Issaka Joseph Boussim Per Christer Oden Sita Guinko 《Annals of Forest Science》2010,67(3):306-306
9.
Loyapin Bondé Oumarou Ouédraogo Issaka Ouédraogo Adjima Thiombiano Joseph I. Boussim 《Plant Production Science》2013,16(2):143-158
ABSTRACT Shea tree (Vitellaria paradoxa) is one of the main native oil plants with high economic value in Africa. Its fruits are used for food, medicinal, cultural and exportation purposes. However, the lack of efficient tools to assess annual fruit production of the species limits the sustainable management of its resources. Therefore, production statistics are useful to organize the activities of the shea sector. This study aimed to (i) assess the interannual variation in fruit production along a climatic gradient in Burkina Faso, (ii) examine fruit production patterns according to climatic zones and tree size, (iii) assess the contribution of high-yielding trees in the annual potential production and (iv) develop allometric equations for estimating fruit yields of the species. The yield of 212 trees distributed across three climatic zones was monitored over four successive years. Within each climatic zone, fruit production was significantly different among years. Fruit production was positively and significantly correlated with tree size. The interannual variation in fruit production at tree individual level was higher in drier climatic conditions. The mean interindividual synchrony was less than 50% in each zone, suggesting a large range in fruit production patterns of the species. Annually, more than 55% of the total fruit production was supported by high-yielding trees. The best regression models for estimating fruit yields had R 2 values of 69–73% with prediction errors ranging from ?7% to 4%. Our findings are useful tools for the planning of rational exploitation of shea tree’s resources and its sustainable management. 相似文献
10.
Katharina Schumann Rüdiger Wittig Adjima Thiombiano Ute Becker Karen Hahn 《Forest Ecology and Management》2010
Non-timber forest products (NTFPs) strongly contribute to livelihood security in the semi-arid tropics. There is increasing concern about the population status of NTFP-providing trees and therefore a need for their sustainable use. Thus, this study examines the impact of land-use type on the multipurpose baobab tree (Adansonia digitata L.) in Burkina Faso, combined with rates and patterns of bark- and leaf-harvesting, and their impact on fruit production. We compared stands in a protected area (W National Park of Burkina Faso) with those of surrounding communal area (fallows, croplands and villages) to obtain an indication on the status of the baobab population, to assess its harvesting tolerance and to estimate to what extent their actual use is sustainable. Our results reveal that land-use type has an impact on the population structure of the baobab. The size class distribution curve of park stands was inverse J-shape which indicates good rejuvenation, while the curve of fallows, croplands and villages stands was bell-shaped, indicating a lack of recruitment. However, a high number of seedlings were recorded in villages. Nearly all baobabs were pruned and debarked in villages, croplands and fallows while half of the individuals were harvested in the park. Most of the trees were pruned and debarked moderately. Debarking and pruning were slightly size specific. Pruning in interaction with tree-size had a significant impact on fruit production. In contrast, debarking had no effect on fruit production. We conclude that despite the land-use impact and the intense harvesting, baobabs are still well preserved in the communal area due to their longevity, extremely low adult mortality rates and traditional management practices. However, land-use intensifications may lead to increasing pressure on baobab populations in the future. Therefore, adapted management strategies are needed to guarantee the persistence of this important species and to avoid a shortage of baobab products. 相似文献