Forest recovery after swidden cultivation across a 40-year chronosequence in the Atlantic forest of southern Bahia, Brazil

Abstract

Tree species composition and structure of a 40-year chronosequence of secondary forests was compared with old-growth forests in southern Bahia, Brazil. Twelve stands were randomly selected that represented three age classes: 10, 25, and 40 year old with four replications in each class. All stands selected had been established after abandonment from swidden cultivation and were surrounded by old-growth forests. In every stand, ten 0.01-ha transects were established and all stems (C5 cm diameter at breast height) were measured and identified. Results were compared with the dataset of two neighboring old-growth sites. Mean diameter, total height, and stand basal area increased with age. Number of trees/ha peaked in 40 year old stands. The results showed that secondary forests in this region take much more than 40 years to recover the structure of old-growth forests. In contrast, species richness recovery was rapid with a continuous accumulation of species with age in secondary forests.Species richness and diversity increased with age as did similarity between secondary stands and oldgrowth stands. More than half of the species found in the 40 year old stands were shared with the neighboring old-growth forests. However, species richness and diversity were higher in old growth sites.

Natural forest regeneration in abandoned sugarcane fields in northeastern Brazil: floristic changes

“…The low level of floristic similarity between the secondary and mature forests indicates that they are in distinct successional stages and corroborates with the hypothesis that the recuperation of the floristic composition of secondary forests occurs only slowly (Chazdon 2003, Piotto et al 2009, Powers et al 2009). However, the sharing of 68 arboreal species between the secondary and mature forests suggests that the flora of the secondary forests at the USJ tends to convergence to that of the mature forests -as has been observed secondary forest, there were no significant overall differences in terms of the habits of the plants in the two regeneration ages (G test, p = 0.55, Table 2).…”

Modulação do estoque de carbono em paisagens fragmentadas da Mata Atlântica em função dos efeitos de borda

“…Additionally, previous studies variously suggest that secondary Atlantic forest may recover the structure of old growth forests after approximately 25-45 years (do Nascimento et al, 2014;Zanini et al, 2014), or much longer (Piotto et al, 2009) and Chave, 2004;Alves et al, 2010;Lindner, 2010). However, those size classes were almost absent from both interior and edge plots in this study (4A).…”

Untitled

“…Outra variável que pode melhor explicar essa riqueza são as florestas da região sul da Bahia estarem em melhor estado de conservação; com maior porcentagem de remanescentes florestais (Ribeiro et al 2009) e a presença de uma matriz de cabruca (plantação de cacau sobre sombra raleada), que é um sistema agroflorestal com maior permeabilidade biótica (Cassano et al 2008;Cassano et al 2014). No entanto, apesar dessa elevada diversidade apontada e de maior conservação em comparação a outras áreas na floresta Atlântica, as florestas do sul da Bahia também já apresentaram significativas perdas bióticas por fatores antrópicos: corte seletivo, fragmentação e perda de habitat (Faria et al, 2009;Pardini et al, 2009) e uso da terra (Piotto et al, 2009), o que interfere no processo sucessional e pode comprometer a perpetuação da diversidade existente. A similar riqueza de Eschweilera entre as áreas avaliadas pode estar associada à baixa riqueza do gênero na floresta Atlântica (seis espécies -Smith et al, 2014), sendo verificado o máximo de três espécies entre as áreas comparadas (Tabela 1).…”