Caracterização estrutural e status de conservação do estrato herbáceo de dunas da Praia de São Marcos, Maranhão, Brasil

Abstract

RESUMOAs dunas costeiras têm sido apontadas como um dos ambientes mais deteriorados do litoral brasileiro ameaçando assim a vegetação de restinga. O objetivo desse estudo foi descrever a fitossociologia do estrato herbáceo da vegetação de Structural characterization and conservation status of the herbaceous stratum at Praia de São Marcos dunes, Maranhão State, Brazil ABSTRACTThe coastal dunes have been identified as one of the most degraded environments. On the Brazilian coast, they threat the "restinga" vegetation. The objective of this study was to describe the phytosociological structure of the herb layer of dune vegetation and assess the conservation status of the area on the Maranhão coast. The study was conducted at São Marcos Beach located in the northern portion of the Maranhão Island. For the phytosociological sampling, we used the plot's method (50 plots of 1 m 2 ), and analyzed the traditional phytosociological parameters of vegetation. Also, there were determined the life forms, phytogeographic distribution and conservation status of vegetation community on site. In the sample of 50 m² we found 35 species from which Paspalum maritimum, Paspalum ligulare, Cassytha filiformis, Chamaecrista hispidula and Euploca polyphylla showed the highest importance value. When calculated for the cover values, the Shannon diversity index (H') was 1.69 nats m -² and it was 3.04 nats m -² when calculated for the frequency values. The area showed predominance of chamaephytes and therophytes indicating an adaptive strategy of vegetation to withstand adverse weather conditions. The sampled ecosystem presented widely distributed species in the Brazilian biomes, being absent endemism. There were identified 14 impacts factors of which five hit more severely the restinga vegetation of the São Marcos Beach. Therefore, more studies are needed with a focus on conservation of dune ecosystems to prevent damage compromising the plant diversity of these areas.

Species richness in restinga vegetation on the eastern Maranhão State, Northeastern Brazil

“…Plants were sampled in the restinga of Sítio Aguahy (02º38'47''S, 44º09'05''W), an area owned by Companhia Farmacêutica Quercegen Agronegócios I Ltda., in the municipality of São José de Ribamar, of the Maranhão State, Brazil; a map of the study site is available elsewhere (Araujo et al 2016). The Sítio Aguahy comprises an area of 400 ha with transitional vegetation coverage, combining fragments of regenerating Amazon Forest, mangrove swamps, and restinga (vegetation with marine influence, according to the IBGE 2012).…”

Dunes in the North coast of Sergipe, Brazil: plant species and their ecological traits

“…Coastal dunes are one of the richest Restinga formations; estimates show that they house 31 to 410 angiosperms species, belonging to 28-283 genera and to 11-88 families (Cordazzo & Seeliger 1995;Amaral et al 2008). Leguminosae is the family with the largest number of species in these environments, which is followed by families Asteraceae and Poaceae (in decreasing order of importance) in coastal dunes in Northern (Santos & Rosário 1988;Araujo et al 2016), Northeastern (Brito et al 1993;Santos et al 2000Santos et al , 2011Leite & Andrade 2004;Viana et al 2006;, Southeastern (Castelo & Braga 2017) and Southern Brazil (Palma & Jarenkow 2008;Ribeiro & Melo-Jr. 2016).…”

Riqueza E Estrutura De Uma Comunidade Vegetal De Dunas Na Planície Costeira De Santa Catarina

“…Tal abrangência parece relacionar-se a vários aspectos como: condições abióticas e de preservação local, a data de realização do levantamento, além do esforço amostral e critérios metodológicos de cada estudo. A combinação desses fatores parece ser determinante na riqueza específica, pois áreas de dunas mais preservadas e protegidas de ventos tendem a ter maior riqueza de espécies (Araújo et al 2016). Os dados obtidos neste estudo corroboram outros levantamentos florísticos em área de restinga no litoral de SC, os quais destacaram Asteraceae (13 espécies) e Poaceae (13 espécies) como as famílias de maior riqueza específica (Danilevicz et al 1990, Souza et al 1992, Daniel 2006, Guimarães 2006, Klein et al 2007.…”

“…Ambas apresentam caules formados por longos estolões ou rizomas de crescimento horizontal rápido e finas raízes adventícias, podendo cobrir uma extensa área do solo (Pfadenhauer 1978, IBGE 2012. Os atributos dessas formas de vida podem ser considerados estratégias adaptativas que minimizam as condições estressantes (e.g., substrato instável, escassez de água, as altas temperaturas e a elevada salinidade), como ocorrem nas dunas (Seeliger 1992, Spanou et al 2006, Araújo et al 2016 (22) Cyperaceae (9) para a estabilização dos cordões arenosos dispostos na região pós-praia (Cordazzo et al 2006). Algumas espécies de Paspalum e Senecio crassiflorus são conhecidas por alcançarem maiores densidades em áreas de declive e expostas ao vento, aproveitando o aporte adicional de nutrientes trazido pelos ventos fortes (Pfadenhauer 1978).…”