Is the alien tree species Maesopsis eminii engl. (Rhamnaceae) a threat to tropical forest conservation in the East Usambaras, Tanzania?

摘要: The East Usambara mountains are globally important for biodiversity conservation. work reported here aimed to clarify whether plantations of Maesopsis eminii, an introduced pioneer tree, a source alien tree invasion or temporary element in protected conservation forest ecosystem these mountains. natural regeneration dynamics M. eminii and indigenous primary species were assessed which up 35 years old, using clustered systematic sampling. A total 103 95 woody observed the sapling lower canopy layers, respectively. Both layers showed abundance Cephalosphaera usambarensis, local also used plantations. was virtually absent layer, its frequency decreased with time. Abundant spontaneous native occurred under eminii. density Allanblackia stuhlmannii, Beilschmiedia kweo Greenwayodendron suaveolens increased, that Newtonia buchananii decreased, In canopy, G. suaveolens, Parinari excelsa Strombosia scheffleri increased relation plantation age. Therefore, no active, risky eradication is needed area, but priority management task should be avoid gaps.