Afromontane old‐field vegetation: secondary succession and the return of indigenous species

Abstract

AbstractSouth‐west Uganda primarily holds afromontane forests within three protected areas: Mgahinga Gorilla National Park, Echuya Forest Reserve and Bwindi Impenetrable National Park. All forests contain portions of old‐field vegetation. The central question of this study, then, is whether and how natural regeneration of afromontane vegetation would take place. A successional pathway consisting of nine plant communities was found for the first 2 years after cessation of agricultural use. A return of afromontane species despite of an initial dominance of neophytes, a diversification of life form spectra and a growing importance of endozoochory with time belonged to the conspicuous characteristics of this secondary succession. To obtain an insight into the role of birds and buffaloes as possible vectors for seed input, I examined their faeces with regard to germinable seeds. Both, bird faeces, as well as buffalo faeces contained germinable seeds originating from the forest flora. Thus, animal dispersal from the forest into the regenerating zones could be documented. The regeneration potential of the soil‐seed bank seems to be limited in its time scale, and only an initial regeneration capacity could be found. A further progressive succession into a secondary afromontane forest depends on an input of diaspores from undisturbed forest sites. Zoochory appears to be one of the most important dispersal mechanisms.