Solutions for ecological and economic problems posed by Hakea sericea invasions rely on scientific knowledge. We conducted a systematic review to analyze and synthesize the past and current scientific knowledge concerning H. sericea invasion processes and mechanisms, as well as monitoring and control techniques. We used ISI Web of Science, Scopus, and CAPES Periodicals to look for publications on the ecological and environmental factors involved in H. sericea establishment (question 1); responses of H. sericea to fire in native and invaded ecosystems (question 2); and H. sericea monitoring and control methods (question 3). We identified 207 publications, 47.4% of which related to question 1, mainly from Australia and South Africa, with an increasing trend in the number of publications on monitoring and modeling. The traits identified in our systematic review, such as adaptations to dystrophic environments, drought resistance, sclerophylly, low transpiration rates, high nutrient use efficiency, stomatal conductance and photosynthetic rates, strong serotiny, proteoid roots and high post-fire seed survival and seedling recruitment, highlighted that H. sericea is a successful invader species due to its long adaptive history mediated by an arsenal of ecophysiological mechanisms that place it at a superior competitive level, especially in fire-prone ecosystems. Integrated cost-effective control methods in selected areas and the incorporation of information on the temporal invasion dynamics can significantly improve invasion control and mitigate H. sericea impacts while maintaining the supply of ecosystem services in invaded areas.

Understanding the relationships between Coffea arabica 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.

Coffee has major importance in tropical landscapes from agronomic, economic and ecological perspectives. Yet the conversion of shade-coffee into full sun monocultures has deep effect on the potential of those systems to conserve biodiversity and ecosystems services (such as pest control and pollination). Despite of this, effect of shade on production has not been sufficiently addressed, particularly in Brazil, the world major coffee producer. This study compared the performance of shaded coffee and full sun management in terms of productivity and production costs. The survey was conducted in Municipality of Mirante da Serra, in the Brazilian Amazon and eight coffee agroecosystems, four under shade and four under full sun were investigated. The results indicate that shaded systems have lower production costs requiring less working hours than sun plantations. The average production cost of shaded agroecosystems was 49.63%, while in systems under full sun, this value was 82.2%. Shaded and full sun productivity did not differ significantly, with higher variance in the former, showing that shaded systems are more heterogeneous. Shaded coffee agroecosystems presented an economically and environmentally viable alternative. The lower production cost enhances economic viability of these ecosystems in Amazon as well as in the rest of the tropics. Such efficiency may have influenced the persistence of these managements, despite the worldwide agriculture intensification tendency.