par Stevart, Tariq 
;Geerinck, Daniel
Référence Bulletin du Jardin Botanique National de Belgique, 71, 2, page (565-573)
Publication Publié, 2001
;Geerinck, Daniel Référence Bulletin du Jardin Botanique National de Belgique, 71, 2, page (565-573)
Publication Publié, 2001
Article révisé par les pairs
| Résumé : | Species richness variation among Orchidaceae of São Tomé (São Tomé and Príncipe; gulf of Guinea) has been investigated using a grid map with 2 km square units. The factors studied were: rainfall and altitude. Disturbance and collection intensity were also considered. The species number in 2 × 2 km squares varies between 1 and 45. Five orchid diversity classes have been determined and applied to the vegetation of São Tomé. The highest values of species numbers were found in submontane forests between 1000 and 1400 m above sea level. Altitude seems to be the most important factor to explain species richness variation, while rainfall below 2000 mm per year appears to be limiting. Disturbance generally reduces species richness. Interpretation of species richness is difficult as the 2 × 2 km grid is too coarse, especially in areas of marked relief. |
