9 Managing Agroecosystem Services Devra I. Jarvis,1* Elizabeth Khaka,2† Petina L. Pert,3 Lamourdia Thiombiano4 and Eline Boelee5 1Bioversity International, Rome, Italy; 2United Nations Environment Programme (UNEP), Nairobi, Kenya; 3Commonwealth Scientifi c and Industrial Research Organisation (CSIRO), Cairns, Queensland, Australia; 4Central Africa Bureau, Food and Agriculture Organization of the United Nations (FAO), Libreville, Gabon; 5 Water Health, Hollandsche Rading, the Netherlands Abstract Agriculture and ecosystem services are interrelated in various ways. Payments for ecological services (PES) and innovative methods of agricultural management, including ecological agriculture, conservation agriculture and the management of biological diversity are options for enhancing ecosystem services in agroecosystems while sustaining or increasing productivity. Successful actions will depend on strong supporting policies and legal frameworks, as well as on developing the knowledge and leadership capacity in farming communities to evaluate the potential benefi ts. The maintenance of ecosystem services and the long-term productivity and stability of agriculture ecosystems requires a paradigm shift in agriculture that moves away from single solutions to production problems towards a portfolio approach that supports multiple ways to better use soil, water and biotic resources to enhance ecosystem services. Background water, soil and biotic features of the environment that surround the agricultural Agricultural production involves a wide range production system. As weather patterns are of ecosystem services and processes that use becoming more unpredictable and extreme, water, soil and biological components of the with prolonged dry spells and very strong agricultural ecosystem, such as: nitrogen storm events (see Chapter 2), the concern cycling, climate regulation, soil formation, over the long-term reduction in total water pest and disease regulation and pollination, in supply, and in the frequency and severity of addition to the obvious food production pests and pathogens, calls for more attention (Chapters 3 and 4). Some of these services to be given to the underlying ecosystem are produced within the agricultural ecosystem services that support these systems (Molden, itself while others rely on the supporting 2007). * E-mail: [email protected] † E-mail: [email protected] © CAB International 2013. Managing Water and Agroecosystems for Food Security 124 (ed. E. Boelee) Managing Agroecosystem Services 125 In natural ecosystems, the relationship total land area (Foley et al., 2005), and it between diversity and ecosystem regulating generates and interacts with an enormous and supporting services has been given range of agroecosystem services. There is a economic value (Diaz and Cabido, 2001), but need to address this underestimation of little attention has been focused on the ecosystem services in farmland, a need to ecological consequences of the loss of biotic develop concepts, policies and methods of diversity within agricultural ecosystems. This evaluating them, and to fi nd ways in which loss can affect the ecosystem regulating they can be maintained and enhanced in a way functions of agroecosystems, their capacity to that is socially acceptable. Agroecosystems support those ecosystem regulating services may very well offer the best chance of and the long-term stability of the ecosystem in increasing global ecosystem services if land and the face of biotic and abiotic stresses (Hajjar et water are managed in a way that enhances al., 2008). In any ecosystem, each time a natural and social capital (Porter et al., 2009). species or variety goes locally extinct, energy Specifi cally, enhancing the supporting and and nutrient pathways are lost, with consequent regulatory services of ecosystems is vital to alterations of ecosystem effi ciency and the meeting the food demands of a population ability of communities to respond to forecast to reach 9 billion by 2050 (UNFPA, environmental fl uctuations (Diaz and Cabido, 2009). 2001). Reduction of crop diversity, and of the associated diversity in agricultural landscapes, together with the associated reduction in Managing Ecosystem Services in functional traits and facilitative interactions, Agriculture has reduced the capacity of agricultural ecosystems to regulate pests, diseases and Swinton et al. (2006) suggest that incentivizing pollinators, to recycle nutrients and to retain a systems approach to agricultural management soil water (Hajjar et al., 2008). (rather than a problem-response approach) A fundamental research question emerges, could support sustainable production as well as therefore, on how to ensure that continued ecosystem services such as climate regulation, increases in agricultural intensifi cation and wildlife conservation, and biological pest productivity can be achieved in ways that use control and pollinator management. Bennett and enhance ecosystem services more et al. (2005) note that the ways in which effectively, as measured by increased stability ecosystems produce services are insuffi ciently and reduced variability in the agricultural understood, and that this uncertainty needs to production systems of small-scale farmers be accounted for in the decision-making (Foley et al., 2005; Tilman et al., 2011). This process. They advise that future management includes increasing the adaptability of agri- questions will have to address the complexity cultural ecosystems in such a way that com- of ecosystems in their social context in order munities and agroecosystems are able to that ecological services can be maintained, and respond to changing conditions without also to assess the degree to which technology debilitating losses in livelihoods, productivity or can substitute for ecological services. ecosystem functions. The ecosystem services framework As discussed in Chapter 4, ecosystem provides a useful umbrella for this endeavour services in agriculture – that is, those other as it can only be achieved by healthy agro- than the production of food or other agricultural ecosystems. Sustainable management plans products – have been assigned relatively low have been advocated for various agro- economic values compared with those in other ecosystems, ranging from hyper-arid and natural ecosystems, largely as a result of a lack dryland systems (Chapter 6), to wetland and of understanding and limited data availability. aquatic ecosystems (Chapter 7). Furthermore, However, 5 billion ha of land is currently as stated in Chapter 4, managing agro- cultivated or used for pasture. This is an area ecosystems for the delivery of multiple services equal to approximately one third of the earth’s considerably improves the value of the land. 126 D.I. Jarvis and E. Khaka et al. For instance, the on-site costs of nutrient such as payments for carbon sequestration in depletion (including soil loss through erosion) rangelands, remains a challenge. in the agricultural sector of sub-Saharan Africa Similarly, health hazards and the pollution vary between countries from less than 1% to of land and water by livestock excreta could be more than 20% of the agricultural gross turned around into enhanced nutrient cycling domestic product (GDP) (Drechsel et al., and increased soil water holding capacity by 2004). The off-site costs, especially in improved management practices. The most controlling erosion, can be much larger, and effective methods for addressing these affect a variety of non-agricultural ecosystems problems in catchments are at the farm or and their services (Enters, 1998). The production facility. Additional measures can protection of these services by reducing soil, control the effects of manure in watercourses, water and land degradation appears to be a e.g. manure can be intercepted and stored in cost-effective investment. Payments for ponds, contaminated water can undergo environmental services (see below) and other on-farm treatment and constructed farm fi nance mechanisms could be good incentives wetlands can be used to reduce the pathogen to use for stopping these off-site costs, but load (Dufour et al., 2012). A potential method they would be context specifi c. described by Masse et al. (2011) for developing more sustainable livestock operations utilizes anaerobic digestion biotechnologies to produce Managing livestock biogas, and by this means reduces the need for supplementary chemical nitrogen and With their many environmental impacts on phosphorus fertilizers. soil, water and the atmosphere (Chapter 4), The recovery of nutrients from manure, an there are many opportunities for ecosystem important contribution to the supporting gains in livestock production systems. For ecosystem service of nutrient cycling, is highly instance, the high emission of greenhouse variable. Approximately 65% of manure gases can be mitigated by practices such as nitrogen is recovered from (industrialized) carbon sequestration in rangelands or improved intensive systems in Europe. Almost 30% of pastures, by reversing deforestation for the this is lost during storage and the maximum production of feedstuffs through increased cycling effi ciency as nitrogen available to crops agricultural productivity and by using other is around 52%, with large differences between methods of intensifi cation (Watson et al., countries (Oenema et al., 2007). In developing 2000; Schuman et al., 2002; Woomer et al., countries too, there is a large range of variation 2004). Much can also be done by keeping in