The expansion of large-scale commercial agriculture has also caused deforestation of some of the most bio-diverse forests in the world, such as in the Amazon, for soybean production , and in Southeast Asian rain forests, for oil palm . Since the 1990s, particularly in Brazil and Indonesia where the greatest amount of deforestation occurred, the agents of deforestation shifted from primarily smallholder to enterprise-driven agriculture for global markets . Much recent forest loss, along with agricultural land conversion, can be attributed to the rapid growth in bio-fuel production, centering in Southeast Asia and Latin America but expanding to Africa. bio-fuel production is driven by mandates for renewable transport fuels, weak land use regulation, production subsidies, and speculation by energy and commodity companies in both developing and industrial countries . Although global estimates of the scale of industrial bio-fuel production are difficult to make, the World Bank calculates that 36 million ha were dedicated to bio-fuel production globally in 2008, doubling the 2004 level. Oil palm production in Indonesia and Malaysia indicates the emerging trajectory: aided by government policies and subsidies, oil palm plantations grew in Indonesia from 3.6 million ha in 1961 to 8.1 million ha by 2009 . The consequences of the expansion of oil palm include ongoing displacement of smallholders, increasing monoculture, and abandonment of food cropping, though the extent to which these effects are occurring remains uncertain . Across the Global South, oil palm and sugarcane plantations may provide only a tenth of the jobs when compared to the livelihoods generated through smallholder farming .Despite expansion of large-scale commercial agriculture, smallholders still make up 85% of circa 525 million farms worldwide . Such farmers span a spectrum from traditional, indigenous growers using no external inputs to those with heavy dependency on modern seed varieties, fertilizers, and pesticides,grow table but up to 50% of smallholders are thought to utilize resource conserving farming methods .

While they represent the bulk of the agricultural population, estimated at circa 2.6 billion people , due to land inequalities they often do not control the bulk of the arable land . These disparities are largest in South America, and least pronounced in Africa . Another sign of intensifying inequalities is that mean farm size has decreased in many parts of Africa and Asia , increasing the vulnerability of small farmers and exacerbating the poverty in these regions, while large landholdings are increasingly controlled by a small number of people . Despite poverty, the current contribution of small farms to global food production is significant. Herrero et al. estimate that mixed crop and livestock systems supply 50% of the worlds’ cereal, 60% of the world’s meat and 75% of the world’s dairy production. Much of this production is locally produced and consumed, and provides the main source of food for the world’s 1 billion poor . Altieri considers that traditional indigenous agriculture supplies 30 – 50% of the world’s food. Nagayets suggests that the contribution of smallholders to food production is increasing in some countries because of changing national socioeconomic and political situations and government policies favoring domestic food self-sufficiency . As indicated previously, not all smallholder agriculture would be considered DFS. Perhaps 50% of smallholder farmers use agro-industrial inputs or have not adopted agroecological methods . Qualitative research suggests that through implementation of “sustainable intensification”, a set of resource conserving practices also used in DFS , such farms could become 60-100% more productive, potentially contributing far more to local and global food security , although rigorous, quantitative comparisons are both lacking and needed . Overall, small-scale diversified farmers face continuous, intensifying pressures from the encroachment of industrial supply chains . However, in parts of the developing world, diversified farming systems are actually expanding, in response to food sovereignty movements, smallholder desires for healthier and more economically independent lives, and some level of civil society and government support. Agroecological techniques are site specific and tend to be transferred from location to location through horizontal communication and social networks, with much adaptation by local communities . Evidence of the rising adoption of agroecological principles in many Latin and Central American countries exist through the many cases of campesino-tocampesino training reported, as well as the increasingly global spread of the La Via Campesina movement .

Cuba is a case where the transition to agroecological practices has been particularly rapid ; in this case the expansion was a response to a severe food security crisis and lack of fossil fuel inputs following collapse of the former USSR and associated subsidies to industrialized agriculture . To some degree, DFS are also expanding in industrial countries despite the vastly more inhospitable political and economic conditions that may prevail, particularly in the U.S. There, as in Australia and many European countries, there is growing demand for organic and locally produced fruits, vegetables, fish, and meat, which is spawning an increase in the number of small-scale, highly diverse farms, often supplying urban markets . In the U.S., certified organic agriculture has grown markedly, rising from less than 1 million acres in 1990 to 4.8 million acres in 2008 and comprises 0.7% of agricultural production with 20,000 producers . Worldwide, organic agriculture has tripled from 11 million ha in 1999 to 37.2 million ha in 160 countries as of 2009 and currently makes up 0.9% of agricultural production , with 1.8 million producers in 2009, predominantly from Asia and Africa. Nonetheless, while organic agriculture tends to support greater biodiversity than conventional farms , not all organic farms are DFS . Much organic agriculture has become increasingly large-scale and homogeneous as producers and food companies strive to maximize profits and meet growing market demand .The series begins by examining what is known about how DFS maintain a range of ecosystem services that provide critical inputs to farming, including soil quality, water use efficiency, control of weeds, diseases and pests, pollination services, carbon sequestration, energy efficiency/greenhouse warming potential, resistance and resilience to climate change, food production, and biodiversity. By comparing DFS to conventional industrial systems, Kremen and Miles find that DFS significantly enhance all the ecosystem services measured with the exception of crop production, although not necessarily to the level required to control pests and diseases or provide sufficient pollination. The authors note that relatively few research dollars have yet been applied to the improvement of DFS compared to conventional systems; redressing this substantial inequality in public and private investment is necessary to close yield gaps while maintaining environmental benefits. The authors recommend that new research should be holistic and integrated across many components of the farming system to identify management systems that can take advantage of potential synergies.

Next, Bacon et al. seek to simultaneously deepen our understanding of the social consequences of DFS vs. industrial production and to unpack several key influences affecting continuity, change, and possibilities for transformation of these systems. Case studies from California’s Central Valley, Mesoamerican coffee agroforestry systems, and agricultural parks in the European Union, identify the critical role of government policy in an agricultural system’s emergence and the combination of market demand and multi-actor governance that provide continuity. They find that the spread of DFS will generate social benefits, including decreased pesticide exposures, improved food security, longer agricultural working seasons, and healthier diets, but may also generate new costs, such as increased muscular skeletal injuries associated with higher manual labor demands. Social movements can alter governance arrangements and influence both the spread of DFS and the creation of policies that increase environmental benefits and reduce social costs. However, broader changes to the market and political structures and economic policies of agriculture are needed to enable a socially sustainable expansion of DFS. Iles and Marsh consider several examples of obstacles to the adoption and spread of DFS in industrialized agricultural systems. These include the broader political economic context of industrialized agriculture, the erosion of farmer knowledge, and supply chain and marketing conditions that limit farmers’ ability to adopt diversified practices. To overcome these obstacles and nurture DFS, policy makers can transform agricultural research, develop peer-to-peer learning processes, support recruitment of new farmers, invest in improved agricultural conservation programs,ebb flow table compensate for provision of ecosystem services in working landscapes, and develop direct links to consumers and institutional markets. In contrast to analyzing a market-led expansion of DFS, Rosset and Martinez-Torrez propose a theoretical framework focused on disputed rural territories and repeasantization to understand how and why rural social movements have increasingly adopted agroecology and diversified farming systems as part of their discourse and practice. Rural spaces are increasingly disputed as agribusiness seeks to “grab land”, control production systems, and remove many rural inhabitants from the land, while small-scale farmers, rural workers, indigenous communities and women are increasingly organized into social movements, such as Via Campesina, that seek to repopulate or maintain these landscapes through the defense of their food, seed, and land sovereignty. For peasants, family farmers and their social movements, agroecology helps both to build autonomy from unfavorable markets and to restore degraded soils. The social process of sharing these practices and values from farmer to farmer , coupled with broader global social movements, help bring alternatives such as DFS to scale.Sayre et al. examine how ranching is the most ecologically sustainable segment of the U.S. meat industry and exemplifies many of the defining characteristics of DFS. Rangelands also provide other ecosystem services, including watershed functioning, wildlife habitat, recreation, and tourism. Innovations in marketing, incentives and easement programs that augment ranch income, creative land tenure arrangements, and collaborations among ranchers can support greater diversification. Taking advantage of rancher knowledge and stewardship can support the sustainability of ranching and its associated public benefits. We have attempted to launch the concept of DFS by encouraging broad based interdisciplinary collaboration and practice from the outset, through combining our analysis of the ecology of food production with complementary questions of food access, distribution, and structure of the agri-food systems. This special feature thus incorporates insights from ecology, economics, political economy, and related social science fields to create a more inclusive analysis of the challenges and opportunities that influence efforts to achieve food security and the multiple dimensions of sustainable agriculture.

Worldwide, the loss of floodplain habitat has resulted in considerable reduction in the productivity and diversity of large river ecosystems . California is no exception, as widespread levee construction separated historical riverine and estuarine floodplain habitats from adjacent river channels . At the same time, there have been corresponding declines in the distribution and abundance of a suite of native fishes , an understandable outcome since a large body of research provides evidence that floodplains are high-quality habitat for multiple Central Valley fishes . Construction of levees in the Central Valley has allowed the development of one of the most extensive and productive agricultural economies in the world . Lands that formerly seasonally flooded can now be farmed in most years. Recently, there has been a growing interest in whether the vast acreage of farmland that now occupies formerly inundated floodplains adjacent to river systems could be managed to improve their value to fish and wildlife . A case in point is the Central Valley Joint Venture Partnership, which promotes the use of flooded rice fields as a means to increase available wetlands to support shorebirds and waterfowl migrating, overwintering, and breeding along the Pacific Flyway . Conservation biologists working in partnership with local farmers have developed a system by which fields are reflooded after rice harvest to create seasonal wetland habitat for water birds during fall and winter. These temporary agricultural wetlands are relatively productive habitats , helping California meet some of its shorebird and waterfowl conservation objectives . The success of these avian-oriented programs raises the question of whether flooded fields can also be used as habitat for native fishes and whether management practices can affect habitat quality. One location where this question is relevant is Yolo Bypass , Sacramento River’s primary remnant floodplain with large areas of agricultural lands .