Changes in floristic composition, community structure and species diversity across a tropical coniferous-broadleaved forest ecotone

Changes in an ecotone may indicate the dynamics between its two adjacent ecological systems. Most of the ecotone studies relevant to coniferous forests were conducted in temperate areas rather than in the tropics. In the low altitude tropical forest region of south China, transition zones exist between tropical coniferous forest and tropical broadleaved forest. To understand the dynamic trends of the forest stands across the ecotones, we compared the compositional and structural features of the three stand zones (the pine forest zone, the ecotone zone and the broadleaved forest zone) at 13 investigation sites, in terms of stand factors, size class distribution, growth-form, and species richness. Stem abundance and species richness increased as the vegetation zones changed from pine forest to the ecotone and then to broadleaved forest. In each stand zone, stem abundance and species richness declined as the size class increased. The coniferous-broadleaved forest ecotone revealed compositional and structural features between its adjacent forest stands. Our results will help design conservation strategies for this unique tropical coniferous forest ecosystem.