Understory structure in two successional stages of a Semi-deciduous Seasonal Forest remnant of Southern Brazil

Abstract

The knowledge of structure and composition of forest strata contributes to understanding the conservation status and dynamics of plant communities. The study of forest understory is important to the knowledge of the succession process. The Seasonal Subtropical Forest remnant named Mato do Silva (27º 55'26" S and 53º 53'15" W) was studied aiming to describe the structure of understory in the late successional forest (LF) and in the young secondary forest (SF), an 11 years old post-agricultural site with canopy dominance of Ateleia glazioveana Baill. The phytosociological survey was carried out through the point quarter method and included individuals of tree and shrub species from 0.5 to 3.0 m of height. The sampling consisted of 384 individuals in LF (67 species) and 284 individuals in SF (20 species). A total of 79 species were observed, and only eight species occurred in both areas. The specific diversity (H') was 3.45 and 2.42 nats in the understory of LF and SF, respectively. The Pielou's evenness index (J) was 0.85 to LF and 0.80 to SF, respectively. Cupania vernalis Camb. and Psychotria leiocarpa Müll. Arg. were the prominent species in the LF while A. glazioveana and Solanum mauritianum Scop. were outstanding in the SF understory. Shade-tolerant and late secondary tree species occurred in large proportion in the LF forest, while pioneers and early secondary tree species predominated in the SF. In addition, certain dominant species in the understory of the SF were absent in the LF understory, such as A. glazioveana, Solanum compressum L. B. Sm. & Downs, Helietta apiculata Bentham and Gledtisia amorphoides (Griseb.) Taubert, which indicates that such species are associated to early stages of forest succession. G. amorphoides is considered an endangered species, and the early successional stages could be necessary for conservation of this species. A decrease in the pH and mineral nutrient levels in the soil was linked to the successional process, indicating the transference of nutrients to the aboveground biomass.

Secondary Serpentine Forests of Poland as a Refuge for Vascular Flora

“…Many plant species are associated with secondary communities because they find favorable habitat conditions in them-the same as in the forests we studied. Such habitats are associated with the occurrence of critically endangered species such as Gleditsia amorphoides [72], Tigridiopalma magnifica [73], Camellia changii [74], or Magnolia stellata [75].…”

Estrato de regeneração natural de uma floresta restaurada com 40 anos

“…A riqueza de espécies amostradas e densidade de indivíduos é superior a diversos levantamentos de regeneração natural realizados em florestas estacionais semideciduais (Grombone-Guaratini, 1999;Franco, 2005;Marangon et al, 2008;Martins et al, 2008, Coelho et al, 2011, até mesmo quando as espécies exóticas são excluídas da contabilização. Esse fato evidencia um resultado satisfatório em nível quantitativo apresentado pelo estrato de regeneração da floresta restaurada, pois levantamentos florísticos e fitossociológicos de fragmentos florestais, principalmente em paisagem regional, são importantes como ecossistemas de referência para a área restaurada que se encontra em processo de avaliação.…”

Woody species recruitment under monospecific plantations of pioneer trees - facilitation or inhibition?

“…Moreover, the diversity tends to increase along the secondary succession, in spite of reduction of nutrients in the topsoil (Coelho et al 2011). In tropical mature forests, differences in floristic composition and diversity could be related to soil fertility, with a negative correlation between diversity and nutrient levels (Huston 1980, Paoli et al 2006).…”