Comparisons of the relative basal area, density and frequency of coffee between shaded and unshaded systems that were abandoned (>70 years) and now are secondary forests in Juiz de Fora, Minas Gerais, Brazil.

<p>Area size was included as random effect to account for the possible confounding effect of patch size in our results and SAR models were performed to reduce spatial autocorrelation between plots. Different letters indicate significant differences between shaded and unshaded systems (p<0.05).</p

Simultaneous autoregressive (SAR) models between coffee basal area and native density (individuals.plot^-1), basal area (cm².plot^-1), absolute species richness (species.plot^-1), rarefied species richness (species.ind^-1), Shannon diversity (H’.plot^-1) of tree and sapling components.

<p>Moran’s I p-values > 0.05 indicate no spatial correlation among plots. The SAR models intercept, β coefficient, p-value and Nagelkerke R squared are given.</p

Bivariate relationships between coffee basal area and native community parameters of sapling and tree components.

<p>a) sapling basal area; b) tree basal area; c) sapling density; d) tree density; e) absolute species richness of saplings; f) absolute species richness of trees; g) rarefied species richness of saplings; h) rarefied species richness of trees; i) Shannon diversity of saplings; j) Shannon diversity of trees; k) percentage of pioneer saplings; l) percentage of pioneer trees. Only shaded systems were included because coffee was absent in most unshaded system plots (22 of 25 plots). Regression lines, confidence interval (95%) and Nagelkerke R² of SAR models are given for both shaded sites (BGJF-1 –solid symbols, N = 25; and MPP–open symbols, N = 10). Sites were included as random effect to account for the nestedness of the plots within sites, and SAR models were performed to reduce spatial autocorrelation among plots.</p

Persistence of <i>Coffea arabica</i> and its relationship with the structure, species diversity and composition of a secondary forest in Brazil

<div><p>Understanding the relationships between <i>Coffea arabica</i> L. and the native tree community of secondary forests regrowing after the abandonment of coffee plantations is important because, as a non-native species in the Neotropics, coffee can outcompete native species, reducing diversity and forests ecosystem services. We aimed to answer three questions: 1) Does coffee regeneration in secondary forests differ between shaded and unshaded abandoned plantations?; 2) How is coffee basal area related to structural attributes, species diversity and composition of the native community?; and 3) Do the relationships between coffee and native community differ between tree and sapling components? We sampled the tree and sapling components in a seasonal tropical dry forest that were previously used as shaded and unshaded coffee plantations. Coffee was the most important species in the sapling component of shaded systems, but was almost absent in unshaded ones. Coffee basal area was negatively related with the native density and absolute species richness of the sapling component; and was negatively related with tree density, and positively related with the percentage of pioneer individuals of the native tree component. Our results indicate that coffee persists in secondary forest communities even after more than 70 years of shaded-coffee plantations were abandoned, potentially reducing density and diversity of native species. Despite limitations, which hinder more general conclusions on coffee invasiveness in Brazilian secondary tropical forests, our results indicate that coffee is a strong competitor in the studied secondary forests and provide important insights for future research on this topic.</p></div