Biodiversity and key ecosystem services in agroforestry coffee systems in the Brazilian Atlantic Rainforest Biome

The thesis reports the results of long-term experimentation (since 1993) of family farmers with agroforestry (AF) coffee systems in the Brazilian Atlantic Rainforest region, a highly fragmented and threatened biodiversity hotspot. The farmers used native trees from forest fragments during a transition from the predominant full sun-coffee (SC) production to more diversified agriculture. The aim of the research was to gain understanding of different agricultural management systems within the complex landscape matrix with respect to farmers’ capacity to diminish negative impacts on the environment, based on an ecosystem services approach.

Participatory Rural Appraisal was used to obtain data from the family farmers. A method of systematization of their experiments created platforms for reflexion and development of agroforestry systems for farmers, technicians and researchers beyond only listing the negative and positive results. Long-term effects of coffee agroforestry (AF), full-sun coffee (SC) systems and surrounding reference forest fragments (RF) were assessed on: tree biodiversity, microclimate, soil quality, costs of labour and inputs and profitability. Selection of appropriate tree species was essential to the success of agroforestry. The main criteria for selecting tree species by farmers were: compatibility with coffee, amount of tree biomass produced, diversification of the production and the labour needed for tree management. The farmers used 85 tree species across the area, 28 of which belonged to the Leguminosae, a family of nitrogen-fixing plants. Most trees were either native to the biome, or exotic fruit trees. The diversification of production, especially with fruit trees, contributed to food security and to a low cost/benefit ratio of AF.

Comparisons between reference forest fragments, agroforestry coffee and sun coffee revealed the potential of AF to conserve local tree biodiversity. Litter quality on-farm was functional in terms of soil erosion and fertility management. The canopy of the trees mitigated high temperature extremes: maximum temperature in SC systems (32oC) was 5.4 oC higher than in AF. Some soil quality parameters (total organic carbon, microbial carbon, soil respiration and potential nitrogen mineralization) showed higher values in RF than AF and SC, but no differences were observed between AF and SC.

There was considerable diversity in the strategies and management of farmers for AF (including the choice of tree species), affecting the productivity and profitability. The total production value of AF was on average 43% higher than that of SC, largely due to other products than coffee. Both systems had an overall higher return of labour than the wage rate in the area.

Continued participative work among scientists and stakeholders may help to increase the delivery of ecosystem services provided by family agriculture. Production systems based on ecosystem service delivery beyond just crop production have potential to reduce the need for external inputs and contribute to major local, regional and global objectives, such as food security, adaptation to climate change and conservation of biodiversity.