22 research outputs found
Woody structure of the plant communities in the Pama Reserve (South-East Burkina Faso, West-Africa)
LÂŽanalyse de dix groupements ligneux et dix espĂšces dominantes a Ă©tĂ© faite du nombre de tiges Ă lâhectare et des classes de diamĂštre des populations correspondantes. Il ressort que les groupements les plus denses sont ceux Ă Combretum nigricans Lepr. ex Guill. & Perr., Anogeissus leiocarpus (DC.) Guill. & Perr., Acacia hockii De Wild. et A. dudgeoni Craib. ex Holland, tandis que les moins denses sont ceux Ă Gardenia ternifolia Schumach. & Thonn., Vitellaria paradoxa C. F. Gaertn. et Piliostigma thonningii (Schumach.) Milne-Redh. La rĂ©partition des individus en classes de diamĂštre a rĂ©vĂ©lĂ© que tous les groupements sont stables, câest-Ă -dire capables de se renouveler par la rĂ©gĂ©nĂ©ration naturelle. Mais la structure des espĂšces dominantes prĂ©sente beaucoup dâirrĂ©gularitĂ©s liĂ©es Ă leurs exigences Ă©cologiques, aux feux de brousse et aux attaques dâĂ©lĂ©phants. Toutefois, la plasticitĂ© Ă©cologique et la biologie de certaines espĂšces leur confĂšrent assez de structures de populations stables. Mots clĂ©s: Aires protĂ©gĂ©es, Burkina Faso, Groupements ligneux, Structure de populationThe analysis of ten plant communities and of the population structure of ten dominant species based on stem numbers per hectare and distribution sizes of corresponding populations revealed a high tree density for the Combretum nigricans community, the Anogeissus leiocarpus community, the Acacia hockii community and the A. dudgeoni community, and a comparatively low density of the communities of Gardenia ternifolia, of Vitellaria paradoxa, and of Piliostigma thonningii. The distribution of individuals into diameter classes revealed that all plant communities are stable, in other words able to maintain their area by natural regeneration. But the population structure of the dominant species showed many irregularities due to their ecological conditions, bush fires and elephant damages. However, ecological plasticity and biology of some species assigned them enough stable structures. Key words: Burkina Faso, Protected Areas, Structure, Woody communitie
Structure des ligneux des formations vĂ©gĂ©tales de la RĂ©serve de Pama (Sud-Est du Burkina Faso, Afrique de lâOuest)
The analysis of ten plant communities and of the population structure of ten dominant species based on stem numbers per hectare and distribution sizes of corresponding populations revealed a high tree density for the Combretum nigricans community, the Anogeissus leiocarpus community, the Acacia hockii community and the A. dudgeoni community, and a comparatively low density of the communities of Gardenia ternifolia, of Vitellaria paradoxa, and of Piliostigma thonningii. The distribution of individuals into diameter classes revealed that all plant communities are stable, in other words able to maintain their area by natural regeneration. But the population structure of the dominant species showed many irregularities due to their ecological conditions, bush fires and elephant damages. However, ecological plasticity and biology of some species assigned them enough stable structures.Lâanalyse de dix groupements ligneux et dix espĂšces dominantes a Ă©tĂ© faite du nombre de tiges Ă lâhectare et des classes de diamĂštre des populations correspondantes. Il ressort que les groupements les plus denses sont ceux Ă Combretum nigricans Lepr. ex Guill. & Perr., Anogeissus leiocarpus (DC.) Guill. & Perr., Acacia hockii De Wild. et A. dudgeoni Craib. ex Holland, tandis que les moins denses sont ceux Ă Gardenia ternifolia Schumach. & Thonn., Vitellaria paradoxa C. F. Gaertn. et Piliostigma thonningii (Schumach.) Milne-Redh. La rĂ©partition des individus en classes de diamĂštre a rĂ©vĂ©lĂ© que tous les groupements sont stables, câest-Ă -dire capables de se renouveler par la rĂ©gĂ©nĂ©ration naturelle. Mais la structure des espĂšces dominantes prĂ©sente beaucoup dâirrĂ©gularitĂ©s liĂ©es Ă leurs exigences Ă©cologiques, aux feux de brousse et aux attaques dâĂ©lĂ©phants. Toutefois, la plasticitĂ© Ă©cologique et la biologie de certaines espĂšces leur confĂšrent assez de structures de populations stables
Structure et productivité en gomme des peuplements à Acacia senegal (L) Willd. et Acacia seyal Del. de Massenya au Tchad
Die Kenntnis des Potenzials und der ProduktivitĂ€t einer Ressource ist eine wichtige Voraussetzung fĂŒr die Entwicklung einer guten Management-Poöitik. Daher wurden Struktur und ProduktivitĂ€t der BestĂ€nde von Acacia seyal und Acacia senegal in der natĂŒrlichen Vegetation von Massenya (Tschad) untersucht. Auf 32 FlĂ€chen von 900 m2 wurden Durchmesser und Höhe aller Gehölz-Individuen. FĂŒr StrĂ€ucher wurde der Durchmesser bei 50 cm vom Boden gemessen. Die jungen Exemplare wurden gezĂ€hlt und Höhenklassen zugeordnet. Die Struktur der Population wurde durch die Anzahl der StĂ€mme pro Hektar und die Durchmesserklassen gekennzeichnet. Der Index des Wertes der Bedeutung (LâIndice de Valeur dâImportance IVI) wurde verwendet, um die PrĂ€valenz der Arten zu beurteilen. Die StandproduktivitĂ€t an Gummi wurde anhand der durchschnittlichen Produktion des Baumes ausgewertet, die 250 g betrug. Die BestĂ€nde von Massenyas Acacia sind sehr dicht (619 ± 269 StĂ€mme / ha), haben aber aufgrund einer hohen Anzahl von Individuen mit kleinem Durchmesser (11,1 ± 2,2 cm) einen geringen Basalbereich (7,1 ± 1,2 mÂČ / ha). Im Allgemeinen handelt es sich hierbei um Strauchpopulationen (Höhe 5,2 ± 0,9 m) mit einem guten Aufkommen von Jungwuchs (408 ± 267 StĂ€mme / ha), der sich natĂŒrlich regenerieren kann. Allerdings scheint Acacia seyal andere Standorte als Acacia senegal zu besiedeln. Von den sieben Arten, die im Untersuchungsgebiet vorherrschen, haben Acacia seyal und Acacia senegal das höchste IVI (79 und 55). Arten mit gutem Regenerationspotential sind Acacia seyal (64,58 ± 8,26 juv./ha), Acacia senegal (58 ± 10 juv./ha) und Guiera senegalensis (51 ± 8 juv./ha). Die jĂ€hrliche Gummiproduktion wird auf 56 ± 6 kg / ha des brĂŒchigen Gummis (Acacia seyal) und 41 ± 5 kg / ha Hartgummi (Acacia senegal) geschĂ€tztKnowledge of the potential and productivity of a resource is a particular need for the development of a good management policy. Therefore, structure and the productivity of Acacia seyal Del. and Acacia senegal (L) Willd. Stands were studied in the natural vegetation of Massenya (Chad). Based on 32 plots of 900 m2, diameter (50 cm above ground) and height of all trees and shrubs were measured. For shrubs, the diameter was measured at 50 cm from the ground. The juveniles were counted and assigned to height classes. The population structure was characterized by the number of stems per hectare and diameter classes. The Index of the Value of Importance (IVI) was used to assess the prevalence of species on the site. Stand productivity was evaluated based on the treeâs mean production which was 250 g. The stands of Massenyaâs Acacia are very dense (619 ± 269 stems/ha), but have a low basal area (7.1 ± 1.2 mÂČ/ha) due to a high number of small diameter individuals (11.1 ± 2.2 cm). In general, these are shrub populations (height 5.2 ± 0.9 m) with good potential for juveniles (408 ± 267 stems / ha) that can regenerate naturally. However, Acacia seyal seems to colonize other environments than Acacia senegal. Of the seven species predominant on the site, Acacia seyal and Acacia senegal have the highest IVI (79 and 55). Species with good regeneration potential are Acacia seyal (64.58 ± 8.26 juv./ha) Acacia senegal (58 ± 10 juv./ha) and Guiera senegalensis (51 ± 8 juv./ha). The annual gum production is estimated at 56 ± 6 kg/ha of friable gum (Acacia seyal) and 41 ± 5 kg/ha of hard gum (Acacia senegal).La connaissance du potentiel et de la productivitĂ© d'une ressource est une donnĂ©e nĂ©cessaire Ă l'Ă©laboration d'une bonne politique de sa gestion. La structure et la productivitĂ© des peuplements Ă Acacia seyal Del. et Ă Acacia senegal (L) Willd.ont Ă©tĂ© Ă©tudiĂ©es dans les formations naturelles de Massenya au Tchad. Sur la base de 32 placeaux de 900 m2, le diameter et la hauteur de tous les individus dâespĂšces ligneuses ont Ă©tĂ© mesurĂ©s. Pour des espĂšces adultes Ă port arbustif, le diameter est mesurĂ© Ă 50 cm du sol. Les individus juvĂ©niles sont simplement comptĂ©s et ranges en classe de hauteur. LâĂ©tude de la structure des peuplements et de deux espĂšces dâAcacia a Ă©tĂ© rĂ©alisĂ©e Ă travers le nombre de tiges Ă lâhectare et les classes de diamĂštre. LâIndice de Valeur dâImportance (IVI) a Ă©tĂ© utilisĂ©e pour apprĂ©cier la prĂ©dominance des espĂšces sur le site. La productivitĂ© des peuplements en gomme a Ă©tĂ© Ă©valuĂ©e en fonction de la production moyenne dâun arbre qui Ă©tait de 250 g. Les peuplements Ă Acacia de Massenya sont trĂšs denses (619 ± 269 tiges/ha), mais Ă surface terriĂšre faible (7,10 ± 1,20 mÂČ/ha) due Ă un grand nombre dâindividus de petit diamĂštre (11,1 ± 2,2 cm). Ce sont des peuplements gĂ©nĂ©ralement arbustif (hauteur de 5,2 ± 0,9 m) avec un bon potentiel de juvĂ©niles (408 ± 267 tiges/ha) pouvant se rĂ©gĂ©nĂ©rer naturellement. Toutefois, Acacia seyal semble plus apte Ă coloniser dâautres milieux quâAcacia senegal. Sur les sept espĂšces qui prĂ©dominent sur le site, Acacia seyal et Acacia senegal rĂ©alisent des IVI plus Ă©levĂ©s (respectivement 79 et 54). Les espĂšces Ă bon potentiel de rĂ©gĂ©nĂ©ration sont Acacia seyal (65 ± 8 juv./ha), Acacia senegal (58 ± 10 juv./ha) et Guiera senegalensis (51 ± 8 juv./ha). La production annuelle de gomme est estimĂ©e Ă 56 ± 6 kg/ha de gomme friable (Ă Acacia seyal) et 41 ± 5 kg/ha de gomme dure (Ă A. senegal)
Magnoliophyta of the partial faunal reserve of Pama, Burkina Faso
The partial faunal reserve of Pama is situated in the province of Kompienga, in the South-East of Burkina Faso, with typical Sudanian savanna vegetation. Adjacent to the Arli National Park and the Pendjari National Park, it is part of the so-called WAP complex, one of the largest wildlife areas in West Africa. Up to now, only little has been known about its flora. The present study aimed at reducing this gap in knowledge, and represents an important tool for conservation and research. The list of species was compiled from the surveys carried out from 2001 to 2004, additional relevé data, and herbarium specimens. We found 450 species, which belong to 244 genera and 73 families. The most species-rich family is Poaceae (83 species), followed by Fabaceae (64), Cyperaceae (24), Rubiaceae (22), Euphor- biaceae (20), Combretaceae (15), Asteraceae (14), Caesalpiniaceae (14), Mimosaceae (12), and Convolvulaceae (11)
DĂ©gradation des aires protĂ©gĂ©es par lâexploitation des ressources vĂ©gĂ©tales : cas de la rĂ©serve partielle de faune de Pama, Burkina Faso (Afrique de lâOuest)
Introduction. Les aires protégées représentent un immense réservoir de ressources
biologiques dont dépendent fortement les populations riveraines. La non-prise en compte
des savoirs locaux constitue souvent un frein aux politiques de conservation et
dâutilisation durable de la biodiversitĂ© dans ces aires. La rĂ©serve de Pama, situĂ©e en
zone soudanienne au sud-est du Burkina Faso, est un bon exemple de la divergence existant
entre les besoins dâautosubsistance des populations riveraines et la nĂ©cessitĂ© de
conserver la biodiversitĂ©. LâĂ©valuation de lâimportance socio-Ă©conomique de cette rĂ©serve
pour les populations riveraines pourrait permettre de mieux adapter la stratégie de
gestion des ressources naturelles. MatĂ©riel et mĂ©thodes. Des enquĂȘtes
ethnobotaniques ont été menées en se basant sur des interviews individuelles. Les
informations obtenues Ă partir de lâinterrogation de 30 personnes ressources ont permis
(1) de recenser les différentes utilisations faites de la réserve par les populations
locales ainsi que lâimpact de ces utilisations sur la flore et (2) dâĂ©valuer la perception
des villageois sur la façon de gĂ©rer les ressources de leur forĂȘt. RĂ©sultats.
Un total de 58 espÚces végétales de la réserve, soit plus de 15 % de la flore locale,
fournissent diverses ressources aux populations riveraines, dont du matériel de
construction (90 % de réponses), des plantes médicinales (73,33 %), des plantes
alimentaires (73,33 %), etc. Les espÚces végétales les plus sollicitées se sont révélées
ĂȘtre entre autres Vitellaria paradoxa (80 %), Parkia biglobosa
(66,67 %), Diospyros mespiliformis (33,33 %), Gardenia
erubescens (33,33 %), Lannea microcarpa (33,33 %),
Tamarindus indica (33,33 %), Andropogon gayanus (26,67
%) et A. chinensis (26,67 %) Certaines de ces espÚces se sont révélées de
plus en plus rares du fait de la dĂ©gradation des conditions climatiques, de lâexploitation
abusive de bois vert et de lâappauvrissement des sols. Conclusion. LâĂ©tude
que nous avons menée sur la réserve de Pama nous conduit à préconiser un renforcement des
mesures de protection de lâenvironnement par lâimplication des populations riveraines. Par
ailleurs, la plantation en champ dâespĂšces utiles en voie de rarĂ©faction serait une action
apte Ă limiter la pression dâexploitation sur la rĂ©serv
[List of species] Magnoliophyta of the partial faunal reserve of Pama, Burkina Faso
The partial faunal reserve of Pama is situated in the province of Kompienga, in the South-East of Burkina Faso, with typical Sudanian savanna vegetation. Adjacent to the Arli National Park and the Pendjari National Park, it is part of the so-called WAP complex, one of the largest wildlife areas in West Africa. Up to now, only little has been known about its flora. The present study aimed at reducing this gap in knowledge, and represents an important tool for conservation and research. The list of species was compiled from the surveys carried out from 2001 to 2004, additional relevé data, and herbarium specimens. We found 450 species, which belong to 244 genera and 73 families. The most species-rich family is Poaceae (83 species), followed by Fabaceae (64), Cyperaceae (24), Rubiaceae (22), Euphor- biaceae (20), Combretaceae (15), Asteraceae (14), Caesalpiniaceae (14), Mimosaceae (12), and Convolvulaceae (11)
CARACTERISATION ANATOMIQUE ET CHIMIQUE DU RONIER (BORASSUS AETHIOPUM MART., ARECACEAE) DU TCHAD / AFRIQUE CENTRALE
International audienceThe tall-palm is a woody tree which one found in islets of stand in the natural vegetation in the localities of Ngam, Goundi, Kimri, Houndouma in Chad. Its trunk, being able to exceed 15m height, is used in the frames of the traditional and semi-modern housings. However, little of scientific and technical works have been performed on this wood to allow its rational use. This paper focuses on the determination of its anatomic and chemical features for the understanding of the physical and mechanic behavior of this wood. Anatomical analyses allowed us to quantify by mean 124 fibers per cm 2 in the duramen and 77 fibers per cm 2 in the sapwood. Chemical analyses performed equally allowed to determine a mean rate of:-63.21 % of cellulose in the duramen and 61.89 % in the sapwood;-9.60 % of hemicelluloses in the duramen and 11.32% % in the sapwood;-19.36% of lignin in the duramen and 19.68% in the sapwood
Geographical patterns of woody plants' functional traits in Burkina Faso
Schmidt, Marco, Traoré, Salifou, Ouédraogo, Amadé, Mbayngone, Elisée, Ouédraogo, Oumarou, Zizka, Alexander, Kirchmair, Ivana, Kaboré, Elice, Tindano, Elycée, Thiombiano, Adjima, Hahn, Karen, Zizka, Georg (2013): Geographical patterns of woody plants' functional traits in Burkina Faso. Candollea 68 (2): 197-207, DOI: 10.15553/c2012v682a
Spatially explicit multi-threat assessment of food tree species in Burkina Faso : a fine-scale approach
Over the last decades agroforestry parklands in Burkina Faso have come under increasing demographic as well as climatic pressures, which are threatening indigenous tree species that contribute substantially to income generation and nutrition in rural households. Analyzing the threats as well as the species vulnerability to them is fundamental for priority setting in conservation planning. Guided by literature and local experts we selected 16 important food tree species (Acacia macrostachya, Acacia senegal, Adansonia digitata, Annona senegalensis, Balanites aegyptiaca, Bombax costatum, Boscia senegalensis, Detarium microcarpum, Lannea microcarpa, Parkia biglobosa, Sclerocarya birrea, Strychnos spinosa, Tamarindus indica, Vitellaria paradoxa, Ximenia americana, Ziziphus mauritiana) and six key threats to them (overexploitation, overgrazing, fire, cotton production, mining and climate change). We developed a species-specific and spatially explicit approach combining freely accessible datasets, species distribution models (SDMs), climate models and expert survey results to predict, at fine scale, where these threats are likely to have the greatest impact. We find that all species face serious threats throughout much of their distribution in Burkina Faso and that climate change is predicted to be the most prevalent threat in the long term, whereas overexploitation and cotton production are the most important short-term threats. Tree populations growing in areas designated as âhighly threatenedâ due to climate change should be used as seed sources for ex situ conservation and planting in areas where future climate is predicting suitable habitats. Assisted regeneration is suggested for populations in areas where suitable habitat under future climate conditions coincides with high threat levels due to short-term threats. In the case of Vitellaria paradoxa, we suggest collecting seed along the northern margins of its distribution and considering assisted regeneration in the central part where the current threat level is high due to overexploitation. In the same way, population-specific recommendations can be derived from the individual and combined threat maps of the other 15 food tree species. The approach can be easily transferred to other countries and can be used to analyze general and species specific threats at finer and more local as well as at broader (continental) scales in order to plan more selective and efficient conservation actions in time. The concept can be applied anywhere as long as appropriate spatial data are available as well as knowledgeable experts