La Végétation Des Inselbergs Du Sahel Burkinabè

Abstract

La végétation des inselbergs du Sahel burkinabèB o i s e t f o r ê t s d e s t r o p i q u e s , 2 0 1 5 , n° 3 2 5 ( 3 )Inselbergs are rocky outcrops characterised by the precarious nature of their edaphic and micro-climatic factors. The aim of this study was to compare the vegetation on inselbergs with the vegetation in the surrounding plains. The data were collected from 900 m 2 sampling plots in the woody stratum and 100 m 2 plots in the herbaceous stratum, by means of random stratified sampling. We conducted a total of 162 surveys, from which we identified 228 plant species belonging to 43 families and 144 genera. On the inselbergs, identified 184 species in 36 families and 136 genera. Cynanchum hastifolium was the only species identified as strictly endemic to the inselbergs. In the surrounding environment, the flora comprises 194 species belonging to 40 families and 127 genera. The average number of species identified per survey was higher in the areas surrounding the inselbergs (23.53 ± 6.28) than on the inselbergs themselves (19.93 ± 4.83). The vegetation on the inselbergs (719.47 ± 337.27 plants/ha) is not as dense as in the surrounding environment (1,389.91 ± 674.79 plants/ha). Given the more pronounced human impacts in the surrounding plains and the relic species and dominant Pterocarpus lucens on the inselbergs, these appear to have become a refuge habitat for certain plant species. The difference between the vegetation on the inselbergs and in the surrounding environment is linked to both edaphic and anthropic factors.Keywords: inselbergs, phytosociology, ecology, Burkina Faso. reSumen VEGETACIÓN DE LOS INSELBERGS DEL SAHEL BURKINÉSLos inselbergs son afloramientos rocosos caracterizados por la precariedad de sus factores edáficos y microclimáticos. El objetivo de este estudio es realizar un estudio comparativo entre la vegetación de los inselbergs y la de los ambientes circundantes. Se recopilaron los datos en parcelas de 900 m 2 para el estrato leñoso y de 100m 2 para el estrato herbáceo siguiendo un muestreo estratificado y aleatorio. Se realizaron 162 inventarios de vegetación. El estudio permitió inventariar 228 especies vegetales repartidas en 43 familias y 144 géneros. En los inselbergs, se catalogaron 184 especies repartidas en 136 géneros y 36 familias. Sólo la especie Cynanchum hastifolium se catalogó como endémica estricta en los inselbergs. En los ambientes circundantes de los inselbergs, el cortejo florístico se compone de 194 especies repartidas en 40 familias y 127 géneros. El número promedio de especies por inventario es más alto en los ambientes circundantes (23,53 ± 6,28) que en los inselbergs (19,93 ± 4,83). La vegetación de los inselbergs (719,47 ± 337,27 pies/ha) es menos densa que la de los ambientes circundantes (1 389,91 ± 674,79 pies/ha). El mayor impacto antrópico en las llanuras circundantes, por una parte, y las especies relictas y la dominancia de Pterocarpus lucens en los inselbergs, por otra, serían un reflejo del carácter de refugio que tienen los inselbergs para algu...

Re-greening of agrosystems in the Burkina Faso Sahel: greater drought resilience but falling woody plant diversity

“…The dominance of Combretaceae (C. micranthum, C. glutinosum, C. nigricans, G. senegalensis and A. leiocarpa) highlighted in this study, and confirmed by post-drought floristic surveys in the Sudano-Sahelian region (Savadogo et al 2007, Bognounou et al 2009, Tindano et al 2015, Kusserow 2017, differs from the 1940s-1950s observations of Lavauden (1941) and Roberty (1946Roberty ( , 1954, which, in addition to the Combretaceae, noted the following as common species: A. ataxacantha, B. senegalensis, Diospyros mespiliformis, B. aegyptiaca, B. costatum, K. senegalensis, P. lucens, Sclerocarya birrea, T. indica and Terminalia avicennioides. The agroforestry parks were then almost all made up of trees in mixed stands dominated by V. paradoxa and P. biglobosa (Roberty 1946(Roberty , 1954.…”

Plant communities on inselbergs in Burkina Faso

“…Plant community were collected in each phytogeographical sector using stratified and random sampling. Phytosociological surveys were carried out using the [ 23 ] method in plots of 30 m × 30 m (900 m 2 ) for the woody stratum [ 17 ] and 10 m × 10 m (100 m 2 ) for the herbaceous stratum [ 8 ]. For each survey, all observed species were listed, and each species was accompanied by its [ 23 ] abundance-dominance coefficient.…”

“…Inselbergs are characterized by their isolation from the surrounding relief and their independence from the regional hydrological network [ 5 , 6 ]. Inselbergs are distinct ecosystems due to the nature of their substrate, and vegetation [ 7 , 8 ]. Inselbergs are characterized by the presence of certain typical plant communities (e.g.…”

Inselbergs: potential conservation areas for plant diversity in the face of anthropization

“…Floristic surveys were carried out on inselbergs and in their surroundings following stratified and random sampling. Data were collected in plots of 900 m² for the woody stratum and 100 m² for the herbaceous stratum (Kouassi et al, 2009;Tindano et al, 2015;Zerbo et al, 2017). The area of the plots in the micro-habitats of inselbergs varied from 0.25 m² to 9 m² depending on the size of the micro-habitat (Büdel et al, 1997;Porembski, 2000;Kouassi et al, 2014b).…”