Patterns of shade plant diversity in four agroforestry systems across Central America: a meta-analysis.

Agroforestry systems can potentially increase tree diversity within agricultural landscapes, but to date, there is little understanding of the patterns of shade plant diversity within different agroforestry systems (AFS) at large spatial scales. Using compiled plant inventory data (from 23 sources, 2517 plots, and 148,255 individuals) encompassing four AFS (shaded coffee; shaded cocoa; dispersed trees on pastures; and live fences) across six countries in Central America we estimated different metrics of diversity to assess the conservation value of different AFS for shade plants. 458 shade plant species were recorded across the four agroforestry systems. Primary forest species accounted for 28% of the shade species recorded, but only 6% of the recorded individuals. No single AFS was consistently the most diverse across countries when considering rarefied species richness. Trees on pastures can potentially reach a similar species richness as cocoa and coffee systems but require sampled areas 7-30 times larger. In terms of composition, 29 species were shared across the agroforestry systems in different countries, illustrating the strong selection pressure of farmers for species that provide timber, firewood, and fruit. Our study highlights the potential contribution and limitations of different AFS for tree diversity conservation within agricultural landscapes.

Arabica-like flavour in a heat-tolerant wild coffee species.

There are numerous factors to consider when developing climate-resilient coffee crops, including the ability to tolerate altered climatic conditions, meet agronomic and value chain criteria, and satisfy consumer preferences for flavour (aroma and taste). We evaluated the sensory characteristics and key environmental requirements for the enigmatic narrow-leaved coffee (Coffea stenophylla), a wild species from Upper West Africa1. We confirm historical reports of a superior flavour1-3 and uniquely, and remarkably, reveal a sensory profile analogous to high-quality Arabica coffee. We demonstrate that this species grows and crops under the same range of key climatic conditions as (sensorially inferior) robusta and Liberica coffee4-9 and at a mean annual temperature 6.2-6.8 °C higher than Arabica coffee, even under equivalent rainfall conditions. This species substantially broadens the climate envelope for high-quality coffee and could provide an important resource for the development of climate-resilient coffee crop plants.

Lost and Found: Coffea stenophylla and C. affinis, the Forgotten Coffee Crop Species of West Africa.

Coffea arabica (Arabica) and C. canephora (robusta) almost entirely dominate global coffee production. Various challenges at the production (farm) level, including the increasing prevalence and severity of disease and pests and climate change, indicate that the coffee crop portfolio needs to be substantially diversified in order to ensure resilience and sustainability. In this study, we use a multidisciplinary approach (herbarium and literature review, fieldwork and DNA sequencing) to elucidate the identity, whereabouts, and potential attributes, of two poorly known coffee crop species: C. affinis and C. stenophylla. We show that despite widespread (albeit small-scale) use as a coffee crop species across Upper West Africa and further afield more than 100 years ago, these species are now extremely rare in the wild and are not being farmed. Fieldwork enabled us to rediscover C. stenophylla in Sierra Leone, which previously had not been recorded in the wild there since 1954. We confirm that C. stenophylla is an indigenous species in Guinea, Sierra Leone, and Ivory Coast. Coffea affinis was discovered in the wild in Sierra Leone for the first time, having previously been found only in Guinea and Ivory Coast. Prior to our rediscovery, C. affinis was last seen in the wild in 1941, although sampling of an unidentified herbarium specimen reveals that it was collected in Guinea-Conakry in 2015. DNA sequencing using plastid and ITS markers was used to: (1) confirm the identity of museum and field collected samples of C. stenophylla; (2) identify new accessions of C. affinis; (3) refute hybrid status for C. affinis; (4) identify accessions confused with C. affinis; (5) show that C. affinis and C. stenophylla are closely related, and possibly a single species; (6) substantiate the hybrid C. stenophylla × C. liberica; (7) demonstrate the use of plastid and nuclear markers as a simple means of identifying F1 and early-generation interspecific hybrids in Coffea; (8) infer that C. liberica is not monophyletic; and (9) show that hybridization is possible across all the major groups of key Africa Coffea species (Coffee Crop Wild Relative Priority Groups I and II). Coffea affinis and C. stenophylla may possess useful traits for coffee crop plant development, including taste differentiation, disease resistance, and climate resilience. These attributes would be best accessed via breeding programs, although the species may have niche-market potential via minimal domestication.

An integrated framework for assessing vulnerability to climate change and developing adaptation strategies for coffee growing families in Mesoamerica.

The Mesoamerican region is considered to be one of the areas in the world most vulnerable to climate change. We developed a framework for quantifying the vulnerability of the livelihoods of coffee growers in Mesoamerica at regional and local levels and identify adaptation strategies. Following the Intergovernmental Panel on Climate Change (IPCC) concepts, vulnerability was defined as the combination of exposure, sensitivity and adaptive capacity. To quantify exposure, changes in the climatic suitability for coffee and other crops were predicted through niche modelling based on historical climate data and locations of coffee growing areas from Mexico, Guatemala, El Salvador and Nicaragua. Future climate projections were generated from 19 Global Circulation Models. Focus groups were used to identify nine indicators of sensitivity and eleven indicators of adaptive capacity, which were evaluated through semi-structured interviews with 558 coffee producers. Exposure, sensitivity and adaptive capacity were then condensed into an index of vulnerability, and adaptation strategies were identified in participatory workshops. Models predict that all target countries will experience a decrease in climatic suitability for growing Arabica coffee, with highest suitability loss for El Salvador and lowest loss for Mexico. High vulnerability resulted from loss in climatic suitability for coffee production and high sensitivity through variability of yields and out-migration of the work force. This was combined with low adaptation capacity as evidenced by poor post harvest infrastructure and in some cases poor access to credit and low levels of social organization. Nevertheless, the specific contributors to vulnerability varied strongly among countries, municipalities and families making general trends difficult to identify. Flexible strategies for adaption are therefore needed. Families need the support of government and institutions specialized in impacts of climate change and strengthening of farmer organizations to enable the adjustment of adaptation strategies to local needs and conditions.

Land use change on coffee farms in southern Guatemala and its environmental consequences.

Changes in commodity prices, such as the fall in coffee prices from 2000 to 2004, affect land use decisions on farms, and the environmental services they provide. A survey of 50 farms showed a 35% loss in the area under coffee between 2000 and 2004 below 700 m with the majority of this area (64 %) being coffee agroforest systems that included native forest species. Loss of coffee only occurred on large and medium-scale farms; there was no change in area on cooperatives. Coffee productivity declined below 1,100 m altitude for sun and Inga shade coffee, but only below 700 m altitude for agroforest coffee. Coffee productivity was 37-53% lower under agroforests than other systems. Increases in rubber and pasture were related to low altitude large-scale farms, and bananas and timber plantations to mid-altitude farms. Average aboveground carbon stocks for coffee agroforests of 39 t C ha(-1) was similar to rubber plantations, but one-third to one half that of natural forest and timber plantations, respectively. Coffee agroforests had the highest native tree diversity of the productive systems (7-12 species ha(-1)) but lower than natural forest (31 species ha(-1)). Conversion of coffee agroforest to other land uses always led to a reduction in the quality of habitat for native biodiversity, especially avian, but was concentrated among certain farm types. Sustaining coffee agroforests for biodiversity conservation would require targeted interventions such as direct payments or market incentives specifically for biodiversity.

Adaptive capacity and social-environmental change: theoretical and operational modeling of smallholder coffee systems response in Mesoamerican Pacific Rim.

Communities who rely directly on the natural environment for their survival typically have developed risk management strategies to enable them to avoid dangerous thresholds of change to their livelihoods. Development policy appropriate for natural resource-based communities requires an understanding of the primary drivers of social-ecological change, the ways in which affected households autonomously respond to such drivers, and the appropriate avenues for intervention to reduce vulnerability. Coffee has been, and still remains, one of the most important commodities of the Mesoamerican region, and hundreds of thousands of smallholder households in the region are dependent in some way on the coffee industry for their livelihood stability. We used the Analytical Network Process to synthesize expert knowledge on the primary drivers of livelihood change in the region as well as the most common household strategies and associated capacities necessary for effective response. The assessment identified both gradual systemic processes as well as specific environmental and market shocks as significant drivers of livelihood change across the region. Agronomic adjustments and new forms of social organization were among the more significant responses of farmers to these changes. The assessment indicates that public interventions in support of adaptation should focus on enhancing farmers' access to market and technical information and finance, as well as on increasing the viability of farmers' organizations and cooperatives.