Breman H, Cissé A M
Asscociated Expert of UNESCO at the "Centre Pédagogique Supérieur", Bamako, Mali.
"Ecole Normale Supérieure", Bamako, Mali.
Oecologia. 1977 Dec;28(4):301-315. doi: 10.1007/BF00345986.
The dynamics of the vegetation were studied in the transition zone from the savannah to the Sahel in order to distinguish between the influence of the recent drought and the influence of overgrazing on the natural rangelands. The drought affected especially the different plant species at the northern limit of their habitat. It is, however, not well possible to speak of a sahelisation of the savannah, since the species in regression were replaced by invaders, like Borreria spp, and not by true Sahelian species. An exception was Blepharis linariifolia, which moved to the south. Grazing affected good fodder grasses like Andropogon gayanus, which were replaced by a legume with a short growth cycle, Zornia glochidiata, and an unpalatable annual grass Elionurus elegans. The species much stimulated by the drought, Borreria spp. and Blepharis linariifolia, did not occur in the intensively grazed pastures.
为了区分近期干旱和过度放牧对天然牧场的影响，对从稀树草原到萨赫勒地区的过渡地带的植被动态进行了研究。干旱尤其影响了处于其栖息地北界的不同植物物种。然而，很难说稀树草原正在萨赫勒化，因为衰退的物种被入侵物种（如糙叶木属植物）取代，而非被真正的萨赫勒物种取代。一个例外是亚麻叶假杜鹃，它向南迁移。放牧影响了优质饲草，如须芒草，被生长周期短的豆科植物小角合萌和一种适口性差的一年生禾本科植物秀丽大穗茅取代。受干旱极大刺激的物种，糙叶木属植物和亚麻叶假杜鹃，在过度放牧的牧场中并未出现。
