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Farming with Nature
The Science and Practice of Ecoagriculture
By Sara J. Scherr, Jeffrey A. McNeely ISLAND PRESS
Copyright © 2007 Island Press
All rights reserved.
ISBN: 978-1-59726-757-1
CHAPTER 1
The Challenge for Ecoagriculture
Sara J. Scherr and Jeffrey A. McNeely
Agriculture dominates land and water use like no other human enterprise, with landscapes providing critical products for human sustenance. Yet because of their predominance, agricultural landscapes must also support wild species biodiversity and ecosystem services (MA 2005). Moreover global demand for associated agricultural products is projected to rise at least 50% over the next two decades (UN Millennium Project 2005). These conflicting trends are prompting farmers and policymakers alike to identify innovative ways of reconciling agricultural production and production- dependent rural livelihoods with healthy ecosystems (Acharya 2006; Breckwoldt 1983; Jackson and Jackson 2002; McNeely and Scherr 2003). Unfortunately, the dominant national and global institutions for policy, business, conservation, agriculture, and research have been shaped largely by "mental models" that assume, and even require, segregated approaches.
During the 21st century, a continuing and growing demand for agricultural and wild products and ecosystem services will require farmers, agricultural planners, and conservationists to reconsider the relationship between production agriculture and conservation of biodiversity.
This chapter introduces a new paradigm, ecoagriculture, defined as integrated conservation–agriculture landscapes where biodiversity conservation is an explicit objective of agriculture and rural development, and the latter are explicitly considered in shaping conservation strategies. The rationale for scaled-up action to promote ecoagriculture landscapes, and the defining characteristics of this new approach, are developed further in this book.
The Current Ecological Footprint of Agriculture
Nearly a third of the world's landmass has agricultural crops or planted pastures as a dominant land use (accounting for at least 30% of total area), which has a profound ecological effect on the whole landscape. Another quarter of land is under extensive livestock grazing, and approximately 1 to 5% of food is produced in natural forests (Wood et al. 2000). The "human footprint" analysis of Sanderson et al. (2002) estimated that 80 to 90% of lands habitable by humans are affected by some form of productive activity. More than 1.1 billion people—most directly dependent on agriculture—live within the world's 25 biodiversity "hotspots," areas described by ecologists as the most threatened species-rich regions on Earth (Cincotta and Engelman 2000; Myers et al. 2002).
Both extensive lower-yield and intensive higher-yield agricultural systems have profound ecological effects. Millions of hectares of forests and natural vegetation have been cleared for agricultural use and for harvesting timber and wood fuels. Half the world's wetlands have already been converted for production (MA 2005). Overuse and mismanagement of pesticides poison water and soil, while nitrogen and phosphorus inputs and livestock wastes have become major pollutants of surface water, aquifers, and coastal wetlands and outlets. Between 1890 and 1990, the total amount of biologically available nitrogen created by human activities increased ninefold, and human activity now produces more nitrogen than all natural processes combined (MA 2005). Agrochemical nutrient pollution from the US farm belt is the principal cause of the biological "dead zone" in the Gulf of Mexico 1500 km (932 miles) away (Rabalais et al. 2002), and similar impacts are felt in the Baltic Sea and along the coasts of China and India. Water supplies and quality for major urban centers and industries are threatened by poor soil and vegetation management in agricultural systems in their watersheds.
Some introduced agricultural crops, livestock, trees, and fish have become invasive species, spreading beyond their planned range and displacing native species (Matthews and Brand 2004; Mooney et al. 2005). Additionally, there are concerns about genetically modified crop varieties potentially becoming invasive species or hybridizing with wild relatives and leading to a loss of biodiversity (Omamo and von Grebmer 2005; NRC 2002; Oksman-Caldentey and Barz 2002). On a broad scale, agriculture fragments the landscape, breaking formerly contiguous wild species populations into smaller units more vulnerable to extirpation. Farmers have generally sought to eliminate wild species from their lands, seeking to reduce the negative effects of pests, predators, and weeds. However, these practices often harm beneficial wild species like pollinators (Buchmann and Nabhan 1996), insect-eating birds, and other species that prey on agricultural pests.
The threats posed by agriculture have been a key motivator for conservationists to develop protected areas where agricultural activity is officially excluded or seriously limited. Nonetheless, the Millennium Ecosystem Assessment (MA) Hassan et al. 2005 calculated that more than 45% of 100,000 protected areas had more than 30% of their land area under crops. In light of political and economic realities, many recently designated protected areas in several African countries explicitly permit biodiversity- friendly agriculture, usually in areas considered category V or VI in the World Conservation Union (IUCN) system (IUCN 1994).
As populations and economies grow around the world, meeting increased demand for both agricultural products and ecosystem services will require that many agricultural landscapes be managed through ecoagriculture approaches.
Meeting Increased Demand for Agricultural Products in Ecologically Sensitive Areas
Human population is expected to grow from a little over 6 billion today to over 8 billion by 2030, an increase of about a third, with another 2 to 4 billion added in the subsequent 50 years (Cohen 2003). Food demand is expected to grow even faster as a result of growing urbanization and rising incomes (OECD-FAO 2005), and assuming hunger is reduced among the over 800 million people currently undernourished (UN Millennium Project 2005). More land will surely be required to grow crops, even more so if biofuels become a greater contributor to energy needs. In Africa alone, land in cereal production is expected to increase from 102.9 million ha in 1997 to 135.3 million ha in 2025 (Rosegrant et al. 2005). Global consumption of livestock products is predicted to rise from 303 million metric tons (t) in 1993 to 654 million t in 2020 (Delgado et al. 1999).
Tilman (2001) predicts that feeding a population of 9 billion using current methods would mean converting another 1 billion ha of natural habitat to agriculture, primarily in the developing world, together with a doubling or tripling of nitrogen and phosphorous inputs, a twofold increase in water consumption, and a threefold increase in pesticide use. A serious limiting factor will be water, because 70% of the freshwater used by people is already devoted to agriculture (Rosegrant et al. 2002). Scenarios prepared by the MA thus suggest that agricultural production in the future will likely have to focus more explicitly on ecologically sensitive management systems (Carpenter et al. 2005).
There are four major reasons why meeting increased demand for agricultural products will often require ecoagriculture systems (Scherr and McNeely 2007).
Most of the Increased Food Production Will Be Grown Domestically and in More "Marginal" or "Fragile" Lands
An estimated 90% of food products consumed within most countries will be produced by those same countries. Total agricultural exports increased sharply between 1961 and 2000, but exports still accounted for only about 10% of production (McCalla 2000). A reduction in developed world subsidies and growing demand from China and India could further spur export agriculture in the developing world (Runge et al. 2003). The general pattern of increased trade with most production for domestic markets seems unlikely to change over the next few decades, even though continuing globalization of agriculture will influence product mix and prices. Changes will depend not only on productivity and quality but also on shifts in relative costs for international shipping and internal overland transport. In addition the distances that need to be covered between major population centers and ports and agricultural regions populations fluctuate, and new centers emerge. Interior populations in large countries will continue to be fed mainly by local and national producers.
The declining rate of growth in agricultural yields in places like the Punjab in India, the US Midwest, and the Mekong Delta indicate that most new production may not come from the areas of highest current grain productivity, and some areas are already experiencing declining yields or productivity of inputs (Rosegrant et al. 2002). Although yields in these places may increase through greater input use, plant breeding, biotechnology, and improved irrigation efficiency (Runge et al. 2003), economic and environmental costs are likely to be high.
Lower-productivity lands (drylands, hillsides, rainforests) now account for more than two-thirds of total agricultural land in developing countries (Nelson et al. 1997). Because current yields are relatively low, technologies that already exist can double or even triple current yields, provided adequate investments, market developments, and attention are given to good ecosystem husbandry (UN Millennium Project 2005). Extensive grain monocultures are not likely to be environmentally sustainable in such areas, calling for more diversified land-use approaches. Though the bulk of new production will come mainly from existing croplands, the most promising areas with significant new land for agriculture are in places like the forest and savanna zones of Brazil and Mozambique. These places are also the main remaining large reservoirs of natural habitat in the world. These habitats would be seriously damaged by simplified, high-external-input production systems, but an ecoagriculture approach could both provide a means to increase food production and retain the natural value of the landscape.
Wild Products Will Continue to Be Important for Local Food Supply and Livelihoods
People in low-income developing countries and subregions will continue to rely on harvesting wild species. Wild greens, spices, and flavorings enhance local diets, and many tree fruits and root crops serve to assuage "preharvest hunger" or provide "famine foods" when the economy or crops fail. Frogs, rodents, snails, edible insects, and other small creatures have long been an important part of the rural diet in virtually all parts of the world (Paoletti 2005). Bushmeat is the principal source of animal protein in humid West Africa and other forest regions, and efforts to replace these with domestic livestock have been disappointing. Fisheries are the main animal protein source of the poor worldwide. In Africa and many parts of Asia, more than 80% of medicines still come from wild sources. Gathered wood remains the main fuel for hundreds of millions of people, while forests and savannas provide critical fodder, soil nutrients, fencing, and other inputs for farming (McNeely and Scheer 2003). Achieving security in food and livelihood will therefore require the conservation of the ecosystems providing these wild foods and other products.
Agricultural Systems Will Need to Diversify to Adapt to Climate Change
Strategic planning for agricultural development increasingly focuses on adaptation of systems to climate change, anticipating rising temperatures and more extreme weather events. The US Department of Agriculture and the International Rice Research Institute have both concluded that with each 1°C increase in temperature during the growing season, the yields of rice, wheat, and maize drop by 10% (Brown 2004; Tan and Shibasaki 2003). Cash crops such as coffee and tea, requiring cooler environments, will also be affected, forcing farmers of these crops to move higher up the hills, clearing new lands as they climb, meaning that montane forests important for biodiversity are likely to come under increasing threat. Effective responses to climate change will require use of alternative seed varieties, modified management of soils and water, and new strategies for pest management as species of wild pests, their natural predators, and their life cycles change in response to climates. Increasing landscape-and farm-scale diversity is likely to be an important response for risk reduction (Diversitas 2002).
Agricultural Sustainability Will Require Investment in Ecosystem Management
The ability to meet food needs and economic demand for agricultural products will be constrained by widespread natural resource degradation that is already either reducing supply or increasing costs of production. Up to 50% of the globe's agricultural land and 60% of ecosystem services are now affected to some degree by land or water degradation, with agricultural land use the chief cause (MA 2005; Pretty et al. 2006). Half the world's rivers are seriously depleted and polluted, and 60% of the world's 227 largest rivers have been fragmented by dams, many built to supply irrigation water. Up to 20% of irrigated land suffers from secondary salinization and waterlogging, induced by the buildup of salts in irrigation water (Wood et al. 2000). The food system will also have to confront the collapse in harvests of wild game and wild fisheries in many regions around the world due to overexploitation and habitat loss or pollution (Hassan et al. 2005). Considerable investments will be required to rehabilitate degraded resources and ecosystems upon which food supplies, particularly those of the rural poor, depend (UN Millennium Project 2005).
Meeting Increased Demand for Ecosystem Services
Many consider conservation of wild biodiversity (genes, species, and ecosystems) to be an ethical imperative. Conservation also supports ecological processes and functions that sustain and improve human well-being, known collectively as ecosystem services (Daily 1997). Ecosystem services can be divided into four categories: (1) provisioning services, providing food, timber, medicines, and other useful products; (2) regulating services, such as flood control and climate stabilization; (3) supporting services, such as pollination, soil formation, and water purification; and (4) cultural services, including aesthetic, spiritual, or recreational assets that provide both intangible and tangible benefits such as ecotourism attractions (Kremen and Ostfeld 2005). "Provisioning" has historically been seen as the highest-priority service provided by agricultural landscapes. But it is now recognized that even the "bread baskets" and "rice bowls" of the world also provide other ecosystem services, such as water supply and quality, or pest and disease control, that are critically important (Wood and Scherr 2000).
Agricultural Landscapes Provide Critical Habitat
The conservation community is moving toward an "ecosystem approach" to conserving biodiversity, in light of the dependence of protected areas on a supportive matrix of land and water use, and creation of biological corridors (CBD 2000). The international community has set a goal of having at least 10% of every habitat type under effective protection by 2015 (The Nature Conservancy 2004). This strategy, if successful, will protect many species and ecological communities. But some estimates suggest that more than half of all species exist principally outside protected areas, mostly in agricultural landscapes (Blann 2006). For example, conservation of wetlands within agricultural landscapes is critical for wild bird populations (Heimlich et al. 1998). Protecting such species requires initiatives by and with farmers. The concept of agriculture as ecological "sacrifice" areas is no longer valid in many regions because agricultural lands both perform services and provide essential habitat to many species. Thus the Convention of Biological Diversity agreed in 2002 to aim for 30% of agricultural lands worldwide to be managed to protect wild flora by 2010 (CBD 2002).
(Continues...)
Excerpted from Farming with Nature by Sara J. Scherr, Jeffrey A. McNeely. Copyright © 2007 Island Press. Excerpted by permission of ISLAND PRESS.
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