Götz Schroth

Agroforestry and biodiversity conservation - traditional practices, present dynamics, and lessons for the future

The environmental services that agroforestry practices can provide, and especially their potential contribution to the conservation of biodiversity, have only recently attracted wider attention among agroforestry and conservation scientists. This new view is consistent with the ecosystem approach to natural resource management advocated by the Convention on Biological Diversity. This collection of six papers, which is based on a Workshop held in June–July 2004, brings together studies of biodiversity impacts of traditional agroforestry practices from Central and South America, Africa and Asia. The contributions highlight the considerable potential of traditional agroforestry practices to support biodiversity conservation, but also show their limits. These include the importance of sufficient areas of natural habitat and of appropriate hunting regulations for maintaining high levels of biodiversity in agroforestry land use mosaics, as well as the critical role of markets for tree products and of a favourable policy environment for agroforestry land uses. In combination the case studies suggest that maintaining diversity in approaches to management of agroforestry systems, along with a pragmatic, undogmatic view on natural resource management, will provide the widest range of options for adapting to changing land use conditions.

Biodiversity conservation in cocoa production landscapes: an overview

Cocoa agroforests that retain a floristically diverse and structurally complex shade canopy have the potential to harbour significant levels of biodiversity, yet few studies have documented the plant and animal species occurring within these systems or within landscapes dominated by cocoa production. In this special issue, we bring together nine studies from Latin America, Africa and Asia that document the contribution of cocoa agroforestry systems to biodiversity conservation, and explore how the design, management and location of these systems within the broader landscape influence their value as habitats, resources and biological corridors. Tree diversity within the cocoa production systems is variable, depending on management, cultural differences, location and farm history, among other factors. Animal diversity is typically highest in those cocoa agroforests that have high plant diversity, structurally complex canopies, and abundant surrounding forest cover. In general, both plant and animal diversity within cocoa agroforests is greater than those of other agricultural land uses, but lower than in the original forest habitat. There are several emerging threats to biodiversity conservation within cocoa production landscapes, including the loss of remaining forest cover, the simplification of cocoa shade canopies and the conversion of cocoa agroforestry systems to other agricultural land uses with lower biodiversity value. To counter these threats and conserve biodiversity over the long-term, land management should focus on conserving native forest habitat within cocoa production landscapes, maintaining or restoring floristically diverse and structurally complex shade canopies within cocoa agroforests, and retaining other types of on-farm tree cover to enhance landscape connectivity and habitat availability.

Projected Shifts in Coffea arabica Suitability among Major Global Producing Regions Due to Climate Change

Regional studies have shown that climate change will affect climatic suitability for Arabica coffee (Coffea arabica) within current regions of production. Increases in temperature and changes in precipitation patterns will decrease yield, reduce quality and increase pest and disease pressure. This is the first global study on the impact of climate change on suitability to grow Arabica coffee. We modeled the global distribution of Arabica coffee under changes in climatic suitability by 2050s as projected by 21 global circulation models. The results suggest decreased areas suitable for Arabica coffee in Mesoamerica at lower altitudes. In South America close to the equator higher elevations could benefit, but higher latitudes lose suitability. Coffee regions in Ethiopia and Kenya are projected to become more suitable but those in India and Vietnam to become less suitable. Globally, we predict decreases in climatic suitability at lower altitudes and high latitudes, which may shift production among the major regions that produce Arabica coffee.

An agenda for assessing and improving conservation impacts of sustainability standards in tropical agriculture

Sustainability standards and certification serve to differentiate and provide market recognition to goods produced in accordance with social and environmental good practices, typically including practices to protect biodiversity. Such standards have seen rapid growth, including in tropical agricultural commodities such as cocoa, coffee, palm oil, soybeans, and tea. Given the role of sustainability standards in influencing land use in hotspots of biodiversity, deforestation, and agricultural intensification, much could be gained from efforts to evaluate and increase the conservation payoff of these schemes. To this end, we devised a systematic approach for monitoring and evaluating the conservation impacts of agricultural sustainability standards and for using the resulting evidence to improve the effectiveness of such standards over time. The approach is oriented around a set of hypotheses and corresponding research questions about how sustainability standards are predicted to deliver conservation benefits. These questions are addressed through data from multiple sources, including basic common information from certification audits; field monitoring of environmental outcomes at a sample of certified sites; and rigorous impact assessment research based on experimental or quasi-experimental methods. Integration of these sources can generate time-series data that are comparable across sites and regions and provide detailed portraits of the effects of sustainability standards. To implement this approach, we propose new collaborations between the conservation research community and the sustainability standards community to develop common indicators and monitoring protocols, foster data sharing and synthesis, and link research and practice more effectively. As the role of sustainability standards in tropical land-use governance continues to evolve, robust evidence on the factors contributing to effectiveness can help to ensure that such standards are designed and implemented to maximize benefits for biodiversity conservation.

Climate change adaptation, mitigation and livelihood benefits in coffee production: where are the synergies?

There are worldwide approximately 4.3 million coffee (Coffea arabica) producing smallholders generating a large share of tropical developing countries’ gross domestic product, notably in Central America. Their livelihoods and coffee production are facing major challenges due to projected climate change, requiring adaptation decisions that may range from changes in management practices to changes in crops or migration. Since management practices such as shade use and reforestation influence both climate vulnerability and carbon stocks in coffee, there may be synergies between climate change adaptation and mitigation that could make it advantageous to jointly pursue both objectives. In some cases, carbon accounting for mitigation actions might even be used to incentivize and subsidize adaptation actions. To assess potential synergies between climate change mitigation and adaptation in smallholder coffee production systems, we quantified (i) the potential of changes in coffee production and processing practices as well as other livelihood activities to reduce net greenhouse gas emissions, (ii) coffee farmers’ climate change vulnerability and need for adaptation, including the possibility of carbon markets subsidizing adaptation. We worked with smallholder organic coffee farmers in Northern Nicaragua, using workshops, interviews, farm visits and the Cool Farm Tool software to calculate greenhouse gas balances of coffee farms. From the 12 activities found to be relevant for adaptation, two showed strong and five showed modest synergies with mitigation. Afforestation of degraded areas with coffee agroforestry systems and boundary tree plantings resulted in the highest synergies between adaptation and mitigation. Financing possibilities for joint adaptation-mitigation activities could arise through carbon offsetting, carbon insetting, and carbon footprint reductions. Non-monetary benefits such as technical assistance and capacity building could be effective in promoting such synergies at low transaction costs.

Farmer strategies for tree crop diversification in the humid tropics. A review

Many tree crop farms in the tropics are in a process of crop diversification, even in regions that have traditionally been dominated by a single tree crop species. Here, we review the factors that drive diversification and that influence farmer choices. We analyze recent literature from tropical Latin America, Africa, Asia, and the Pacific Islands, with emphasis on West and Central Africa. We use a framework that distinguishes farmer objectives in diversifying; the opportunities and constraints caused by environmental, technological, market, and policy factors; and farmer characteristics. Our main findings are: (1) Farmers diversify to increase their income by adding more lucrative crops. They diversify also to spread their income to lean times between the harvests of their traditional crops. In addition, farmers diversify to maintain or increase their food security especially while young tree crops are maturing and to reduce their vulnerability to environmental, market, and policy shocks. (2) Famers take advantage of opportunities and are subject to constraints. These include: heterogeneous site characteristics; the legacy of previous forest vegetation; emergent market opportunities from growing urban centers; a diversity of products and market outlets for some crops that reduces marketing risks; government policies; labor constraints that favor certain crops; the availability of investment capital that influences particularly the timing of diversification decisions; and access to improved planting material. (3) Diversification decisions also depend on farmer characteristics such as their age, education, financial situation, and farm and family size. Young farmers are not always more active in diversification than older farmers, although diversification and crop change are often related to generational change. Returning urban migrants have often had a positive effect in terms of diversification and innovation. (4) Diversification is often a response to structural environmental degradation caused by decades of tree crop monocultures. We conclude with a list of areas where government and non-government organizations can support farmers in their diversification decisions.

Climate change, cocoa migrations and deforestation in West Africa: What does the past tell us about the future?

Cocoa farming has been a major driver of deforestation in West Africa, notably in Côte d’Ivoire, the world’s leading cocoa producer. Cocoa has been a “pioneer crop” that was grown after forest clearing, and instead of replanting aging plantations, farmers usually migrated to the forest frontiers to establish a new cocoa farm. During the second half of the twentieth century, the cocoa frontier moved from the drier east to the wetter southwest of the country, fueled by massive immigration of prospective cocoa farmers from the savanna. It has been argued that the climate gradient was a major driver of these east–west migrations and that cocoa farmers, by replacing forest with farm land over vast areas, contributed to the further drying of the climate in a positive feedback cycle. If this were the case, then a hotter and drier future climate would likely continue to push cocoa farmers into the wetter southwest of the sub-continent, with the last forest reserves of southwestern Côte d’Ivoire and Liberia as the only remaining destinations. Based on an analysis of long-term rainfall measurements in major cocoa growing areas of Côte d’Ivoire and interviews with cocoa farmers about their history and motives of migration, we argue that climate and drought have been supporting factors, but not usually the main drivers of cocoa migrations, which were mostly a response to the perceived availability of forest land for planting. We also show that the observed decrease in rainfall in the cocoa regions during the 1970s and 1980s was not primarily a response to local deforestation related to cocoa farming, although deforestation may have caused microclimatic changes. Climate extremes like the 1982/3 drought have also triggered adaptations of farming practices like replanting and crop diversification. To prevent cocoa farming from continuing to act as a driver of deforestation in a hotter climate, governments and supply chain actors should discourage forest frontier dynamics and should help cocoa farmers adapt to environmental change by adopting more intensive and diversified farming practices, building on farmers’ own risk mitigation and adaptation strategies.

Winner or loser of climate change? A modeling study of current and future climatic suitability of Arabica coffee in Indonesia

Previous research has shown that the production of Arabica coffee (Coffea arabica), the main source of high-quality coffee, will be severely affected by climate change. Since large numbers of smallholder farmers in tropical mountain regions depend on this crop as their main source of income, the repercussions on farmer livelihoods could be substantial. Past studies of the issue have largely focused on Latin America, while the vulnerability of Southeast Asian coffee farmers to climate change has received very little attention. We present results of a modeling study of climate change impacts on Arabica coffee in Indonesia, one of the world’s largest coffee producers. Focusing on the country’s main Arabica production zones in Sumatra, Sulawesi, Flores, Bali and Java, we show that there are currently extensive areas with a suitable climate for Arabica coffee production outside the present production zones. Temperature increases are likely to combine with decreasing rainfall on some islands and increasing rainfall on others. These changes are projected to drastically reduce the total area of climatically suitable coffee-producing land across Indonesia by 2050. However, even then there will remain more land area with a suitable climate and topography for coffee cultivation outside protected areas available than is being used for coffee production now, although much of this area will not be in the same locations. This suggests that local production decline could at least partly be compensated by expansion into other areas. This may allow the country to maintain current production levels while those of other major producer countries decline. However, this forced adaptation process could become a major driver of deforestation in the highlands. We highlight the need for public and private policies to encourage the expansion of coffee farms into areas that will remain suitable over the medium term, that are not under legal protection, and that are already deforested so that coffee farming could make a positive contribution to landscape restoration.

Unsaturated Soil Hydraulic Conductivity in the Central Amazon: Field Evaluations

Determination of hydraulic properties may be required to solve many questions in agriculture and environmental research. Hydraulic properties are spatially and temporally variable, consequently, reliable soil hydraulic characterization is complex and time-consuming. Furthermore, many hydraulic properties are better represented by functions (i.e., unsaturated hydraulic conductivity and soil water retentivity) rather than by the mean values. The variability due to the presence of macropores or soil cracks commonly found in some soil classes in the tropics can enhance the naturally high soil hydraulic variability. A tension infiltrometer is an equipment that can be used to evaluate near-saturated hydraulic conductivity and sorptivity. In structured soil, small changes in soil tension, near the saturation, lead to dramatic changes of the infiltration rates. In this chapter, firstly, a discussion about soil hydraulic parameters and methods more appropriate to evaluate them on tropical soils is provided. Specific sources of errors and procedures to avoid or alleviate them are pointed out. Secondly, unsaturated hydraulic conductivity measurements carried out using a tension infiltrometer are used to compare different land use systems in the Central Amazon. The scaling theory and the statistical techniques of piecewise continuous regression are briefly described and used to analyze the results. Tension infiltrometers show to be relatively cheap, robust and a simple field method to evaluate unsaturated hydraulic conductivity in tropical soils. Since K near saturation is highly variable, the data were better analyzed using the relative hydraulic conductivity and the scaling theory. These small values of the tension in the breakpoint that divide the fluxes dominated by gravity reflect the importance to evaluate unsaturated hydraulic onductivities near saturation.

Benefits of biodiversity conservation to agriculture and rural livelihoods

Abstract Well-managed protected areas (PAs) can halt habitat loss, and most countries have made commitments to expand their PA systems. Yet critics argue that even existing PAs deprive countries of needed agricultural lands and, given increased global agricultural demand, such expansion is unacceptable. This paper explores these issues at successive scales - from global to local. First, we examine potential conflicts between agriculture and PA expansion in forested regions using global-scale data. Second, we investigate the value of ecosystem services that support agriculture (e.g. erosion control, soil formation, pollination, biological control, and production of non-timber forest products) to regions identified as global priorities for biodiversity conservation, and spatially quantify the value of ecosystem services to agriculture. Third, we move to regional and national scales, examining how loss of forest services can reduce agricultural production, potentially compromising livelihoods. Finally, we examine ways to integrate agriculture and biodiversity conservation for sustainable landscapes and livelihoods. Across all scales, research demonstrates that in most places, it is both possible and desirable to expand the area for biodiversity conservation, thereby protecting ecosystem services that are vital to sustainable agricultural production and local livelihoods.