Pioneer species distribution in treefall gaps in Neotropical rain forest; a gap definition and its consequences

摘要: An attempt was made to evaluate the consequences of applying a strict definition (Brokaw 1982a) delimitation forest gaps in field. The northernmost Neotropical rain forest, at Los Tuxtlas, Mexico, searched for young (1–2 years old) single-event that would meet criteria definition. In 60 ha only 12 such containing pioneer species could be found. Thirty-three (shrubs and trees) were used as indicator gap conditions. Gap size, measured projected canopy opening (sensu Brokaw 1982a), underestimated from 44 515% size area colonized by species. On average 3.4 times larger than opening. majority showed relative preference borders, an generally not included Pioneer plant abundance density, richness did differ significantly between centres borders. Floristical variation related or location gap. These findings can explained if environment (to which plants respond) is seen result many interacting factors, one. It concluded delimiting field proposed (1982a) cannot regarded applicable definition, its value comparative standard doubtful.