Estrutura Da Comunidade Árborea De Um Fragmento De Mata Ciliar Do Rio Taquari, Colinas, Rio Grande Do Sul

Abstract

RESUMOAs matas ciliares são fundamentais na proteção de mananciais hídricos. O estudo objetivou conhecer a estrutura da comunidade arbórea de uma faixa de mata ciliar do Rio Taquari, no município de Colinas, Rio Grande do Sul. A amostragem foi realizada através da distribuição de 18 unidades amostrais (UA's) de 100 m 2 , a cada 20 metros, formando um transecto paralelo ao rio. Nas UA's foram amostrados os indivíduos com circunferência do caule à altura do peito igual ou superior a 20 cm. Foram definidos os parâmetros de densidade, frequência e dominância, absolutas e relativas, e o índice de valor de importância (IVI). A diversidade foi estimada pelos índices de Shannon (H') e equabilidade de Pielou (J). Foram amostrados 415 indivíduos, 39 espécies e 21 famílias botânicas, sendo Fabaceae a família de maior riqueza. A densidade de indivíduos por hectare foi estimada foi 2.306 ind.ha -1 . Machaerium paraguariense Hassl. apresentou os maiores valores de densidade (367 ind.ha -1 ) e também de IVI (16,0). A diversidade florística estimada pelos índices de H' e J resultou em 3,09 nats.ind. -1 e 0,84, respectivamente. Apesar de ser constituído por uma estreita faixa de mata, o fragmento estudado encontra-se em bom estado de conservação, pois apresenta altos índices de diversidade e o registro de apenas duas espécies exóticas, ambas com baixo IVI.Palavras chaves: Bacia Hidrográfica do Rio Taquari-Antas. Floresta de galeria. Florística. Formação ribeirinha. Fitossociologia. Mata ribeirinha. ABSTRACTThe riparian forests are fundamental for the protection of water springs. This study intended to investigate the community arboreal structure of a Taquari River riparian fragment, in Colinas, Rio Grande do Sul. The sample was done through the distribution of 18 sampling units of 100 m 2 , taken every 20 meters, forming a transect parallel to the river. In the units were sampled the individuals which had from the circumference of the stem to the height of the chest equal or higher than 20 cm. The parameters of density, frequency and dominance, absolute and relatives, and the index of importance value (IVI) were defined and the diversity was estimated for the Shannon (H') and equability of Pielou (J). 415 individuals, 39 species and 21 botanical families were sampled, being Fabaceae the family with higher wealth. The individuals density for hectare were estimated in 2.306 ind.ha -1 . Machaerium paraguariense Hassl showed the highest values of density (367 ind.ha -1 ) and also of IVI (16,0). The floristic

Diversity and indicator species in the cerrado biome, Brazil

“…The riparian forest had the lowest density (560 ind.ha -1 ) in this study and in studies carried out in other areas, for example, 723 ind.ha -1 in riparian forest of Carinhanha River basin (state of Bahia, Brazil; Gomes et al, 2014), 2.306 ind.ha -1 in the Taquari-Antas River basin (state of Rio Grande do Sul, Brazil; Teixeira et al, 2014), 3.788 ind.ha -1 in gallery forests of Acampamento (Distrito Federal, Brazil;Guarino and Walter, 2005), 3445 ind ha -1 in the riparian forest of the Gurguéia River (state of Piauí, Brazil; Silva et al, 2015), and 1.475 ind.ha -1 in flooding areas of the Canjerana Park (Distrito Federal, Brazil;Dietzsch et al, 2006). The low plant density observed in the riparian forest evaluated is apparently related to annual perturbations, such as natural floods that soak the soil increase superficial runoff, carrying organic matter, seeds, and seedlings and saplings of local species into the waterbody.…”

Phytosociological study of a riverine forest remnant from Taquari river, State of Rio Grande do Sul, Brazil

“…As in this study, Myrtaceae and Fabaceae (followed by Euphorbiaceae) are also the most representative in other studies conducted in south Brazil riparian forests (Araujo et al 2004, Brackmann & Freitas 2013, Lucheta et al 2015, Mundeleski et al 2008, SEMA/UFSM- RS 2002, Teixeira et al 2014.…”

“…The absolute density (AD) of the studied area was intermediate when compared to the ones recorded by Teixeira et al (2014) and Lucheta et al (2015) on the same river banks, using the same sampling methods and criteria for individual inclusion. Teixeira et al (2014) recorded AD of 2,305.56 ind ha -1 in a narrow forest zone, while in the fragment studied by Lucheta et al (2015) the AD was of 1,373 ind ha -1 . The comparison of these values reinforces the existence of differences in riparian forests community structure, even when considering the same river.…”

“…Lucheta et al (2015) and Marchi & Jarenkow (2008) also recorded higher ADo values for L. divaricata, 5.66 m² ha -1 and 8.60 m² ha -1 , in their studies on riverine forest fragments in RS, although being lower than values found in this study. In the fragment studied by Teixeira et al (2014) in the same river, L. divaricata had an ADo of only 3.86 m² ha -1 , showing community structure differences, even though fragments were not so distant from each other.…”

“…In the case of T. australis, from the 49 individuals sampled, 40 had more than one stem, and one individual reached 53 stems. By consulting field data obtained in studies by Lucheta et al (2015) and Teixeira et al (2014), in fragments that underwent little flood influence, it was found that individuals have few stems. On the other hand, individuals with many stems was found in riparian forests in Rio Grande do Sul (Dorneles et al 2013, Oliveira et al 2015, indicating possible adaptation to water strength in flood, since this strategy reduces the exposed surface and allows the water to pass through the stems, preventing their removal.…”