Composição, estrutura e aspectos ecológicos da floresta ciliar do rio Araguari no Triângulo Mineiro

Abstract

-(Composition, structure and ecological aspects of the riparian forest of the Araguari River within Triângulo Mineiro region). The study aimed to characterize the tree community of a riparian forest, one of the remnants on the Araguari River, at Uberlândia, Triângulo Mineiro, Minas Gerais State. The study was investigated by phytosociological survey of 110 plots of 10 m × 10 m (1,1 ha). All trees with CAP ≥ 15 cm were registered. There were sampled 1,393 trees distributed in 89 species and 36 families. Hirtella gracilipes (Hook.f.) Prance was the most abundant specie, with the highest frequency, density and VI. The Shannon index was H' = 3,65 nats.ind -1 . The analysis of the vertical structure indicated the occurrence of three strata in the riparian forest: the canopy, the understory and an intermediate stratum. The floristic comparisons indicated that the riparian forest of Araguari River is more similar to the Triângulo Mineiro forests and to gallery forests of the Central Brazil, than to riparian forests of south-southeastern of Minas Gerais and São Paulo.

Impacts of artificial reservoirs on floristic diversity and plant functional traits in dry forests after 15 years

“…less deciduous and more evergreen species will occur, creating barriers to dispersal (Fathi-Moghadam, 2007;Cassiani et al, 2008). Second, because water can be used by zoochoric species to produce bigger and more succulent fruits (Pinheiro and Ribeiro, 2001; Rodrigues et al, 2010), increasing their presence in the fauna and, as a consequence, increasing the dispersal of their seeds (Gusson et al, 2011). A clear example was Myrsine umbellata, a zoochoric and evergreen species with low tolerance to water deficit (Silva and Dillenburg, 2007), but it dominates sector B after 15 years under the influence of the dam.…”

Cambios estacionales acelerados en comunidades boscosas debidos al aumento en la humedad del suelo después de la construcción de una represa

“…The organic carbon allocated in these forests does not compensate for the carbon lost by flooding of the original riparian forest. Original riparian forests in this region covered about 40m 2 /ha (Rodrigues, Lopes, Araújo, & Schiavini, 2010), and many were entirely flooded. Furthermore, the increases in basal area and turnover rates were extremely high in the first two years after damming, but decreased in T2-T4 (the period of two to four years of measurement).…”

Rapid changes in tree composition and biodiversity: consequences of dams on dry seasonal forests

“…The increase in richness and diversity, however, will not mean a "total" conversion of these dry forests into a typical riparian forest due to the maintenance of most of the species in the community, and a few species are lost. Riparian forests are species richness systems (Rodrigues and Nave 2000), due to the high heterogeneity, such as floods (Lopes and Schiavini 2007), distinct water flow (Jansson et al 2000), and great soil moisture variations (Rodrigues et al 2010), and despite that new species appeared, some characteristics of the original forest were constant.…”

“…Second, the new artificial lake created did not have a water current, and thus the sediment and seed deposition from upstream plants would not occur. Flow regime influences species composition and distribution on a small scale (Bendix and Hupp 2000;Hughes and Rood 2003), because many seeds are dispersed by hydrochory (Jansson et al 2000) and because soil deposition creates patches with distinct soil infiltration and nutrients (Rodrigues et al 2010), increasing patches with environmental heterogeneity for the establishment of different species. Therefore, free-flowing rivers have more species-richness than regulated ones after long periods (Dynesius et al 2004;Nilsson et al 1997).…”