Dinâmica de uma comunidade arbórea de várzea no Parque Natural Municipal Porto Velho-Rondônia

Abstract

Floodplain forests are subject to flooding that generates the zoning of species into communities that are organized according to the flood level gradient provided by temporal differences and flood amplitudes. This study aimed to evaluate the changes in the forest structure and dynamics of one hectare of a floodplain tree community, located in the Porto Velho Municipal Natural Park-Rondônia. An inventory was carried out in 100 permanent sampling units of 10 m x 10 m in two moments: 2014 and 2020. In the remeasurements of the stems of the individuals of the first moment, the dead ones were recorded. For recruit individuals, all trees with a diameter at 1.3 m above ground (DBH) greater than or equal to 10 cm were measured. The phytosociological parameters and ecological index were estimated for the second moment. In 2020, 609 individuals were sampled, belonging to 34 families, 60±63 general 129±131 species, with the recruitment of 19 new species. The Shannon-Weaner specific diversity index (H’) was 4.07 nats.Ind. and Pielou equivalence 0.84. The site presented mortality rates (2.48%/year⁻¹) and recruitment (2.23%/year⁻¹) within the ranges for tropical areas. The doubling time (32 years) and half-life (29 years) can be considered short. The annual periodic increase in diameter was 0.26 cm/year, within the range of values ​​for humid areas. The diametric structure demonstrated that the area did not undergo environmental disturbance. The Park area acts as a refuge for four endangered species: Hymenolobium excelsum, Caraipa rodriguesii. Vochysia rufescens and Eschweilera romeu-cardosoi