astonishing 44% of which is endemic (Klink and Machado, 2005). Government policies played a major role in stimulating agricultural conversion in the cerrado, as they did in the Amazon. Starting in the 1960s, government policies aimed at generating foreign exchange through the production of export crops, principally soybean, combined with a desire to populate what was perceived as a vast “empty space” in the country’s interior, led to subsidized loans, the development of infrastructure and other incentives to open up the cerrado (Wood et al., 2000; Klink and Machado, 2005). As a result, by 2002 more than half the original vegetation of the cerrado had been cleared for human use (Klink and Machado, 2005), with more than 70% of the farmed area dedicated to cattle production, generally of low intensity (Wood et al., 2000). Most of the rest is dedicated to large-scale, mechanized soybean production, oriented towards the export market. Likewise, due to the expansion of soybean, Argentina now has rates of deforestation that are 3 to 6 times the world averages (Jason, 2004) (Box 1-7).

Declines in on-farm biodiversity. As an ever-increasing proportion of Latin America’s land is cleared for agriculture, agricultural plots themselves and the semi-natural areas that often surround them have become more important habitats for species that are able to adapt to disturbed environments. There is evidence that use of some traditional practices leads to enhanced on-farm biodiversity, as compared to more intensive farming methods. Harvey et al. (2004) review the literature for Latin America and conclude that practices that increase the variability of habitats available on farm, such as live fences, windbreaks and isolated trees, have had a demonstrable impact on taxa such as birds and mammals. Other studies have demonstrated linkages between increased biodiversity and both organic agriculture and shaded tropical agriculture, such as shade coffee (Perfecto et al., 1996; Perfecto and Armbrecht, 2003; Buck et al., 2004). As farming systems have evolved to more technology-intensive over the last half century, many of these more sustainable practices have been abandoned (McNeely and Scherr, 2003). Consequently, the amount of wild biodiversity supported on farms has decreased over time. In his global analysis, Donald (2004) found that the increase in production of the five major commodities in the world (soybean, rice, cacao, coffee and oil palm) were achieved through an increase in the area planted as well as an increase in yield per area, both of which led to environmental degradation and a massive loss of biodiversity. These negative environmental impacts were a consequence of both habitat loss and environmental contamination due to the use of agrochemicals. Similarly, Robinson and Sutherland (2002) documented the reduction of biodiversity due to agriculture in post-war Britain. They also present evidence that the loss of biodiversity was due to both habitat loss and habitat degradation (i.e., contamination with pesticides and other agrochemicals as well as the homogenization of the farm habitat).

Impacts of freshwater ecosystems. Freshwater ecosystems are very poorly understood, but it is clear that they are highly threatened worldwide (Abell, 2002; Olson and Dinerstein, 2002; MA, 2005b). Conventional/productivist agriculture

 is a major source of threat to these systems. A recent assessment of Latin America’s freshwater biodiversity concluded that more than 85% of freshwater biodiversity in the region is seriously threatened (Olson and Dinerstein, 2002).
     Threats related to agriculture include direct habitat conversion, for example in the case of wetlands drained for agricultural use; sedimentation from the loss of riparian and catchment basin forests; and pollution and eutrophication from agrochemicals, fertilizers and fish farming. The introduction of non-native species, often as part of fish farming initiatives, is a particular problem for lakes; unintentional escapes from fish ponds into streams and rivers are also problematic (ILEC, 2005). Dams and channelizations constructed for flood control or irrigation and excessive water withdrawal, are another source of impact related to agriculture. An emerging issue with dams is the importance of environmental flows, that is, the timing and size of flows necessary for maintaining downstream ecosystems. Pollution from waste produced by processing agricultural crops also impacts freshwater biodiversity (Clay, 2004; ILEC, 2005). Finally, direct exploitation of freshwater fish for food is also an important threat.
     While these problems have not been well-studied in Latin America, there is some evidence of their impact in particular places. Agostinho et al. (2005) review studies of impacts from various threats to freshwater systems in Brazil. There is evidence of reduced species diversity and alteration in community structure in freshwater bodies subject to pollution or eutrophication. Siltation caused by intensive agriculture has been documented as impacting freshwater biodiversity in the Pantanal, the Cerrado and in streams in the highly threatened Atlantic Forest, as well as the Amazon. In Chile, native lake fishes appear to have declined with the establishment of populations of rainbow trout, an exotic species, in the 1900s. With explosive growth in the Chilean aquaculture industry and Chile poised to become the worldwide leader in salmon production, there is concern about the impact of runaway salmon on native fish populations as well (Gajardo and Laikre, 2003).

Contamination and degradation of aquatic and terrestrial ecosystems. Agriculture also impacts biodiversity beyond the conversion of natural habitat. In particular, the use of agrochemicals in the conventional/productivist system results in contamination and degradation of ecosystems. Agrochemicals can harm species that utilize agricultural landscapes or nearby areas and they have a major impact on aquatic and marine biodiversity. Pesticides persist in the environment and many disperse globally as a result of drift, soil volatilization and evaporation (Kurtz, 1990). Pesticides have caused extensive contamination of the soil (Kammerbauer and Moncada, 1998), surface water and groundwater (Dalvie et al., 2003), marine and estuary sediments (Bhattacharya et al., 2003), rain (Quaghebeur et al., 2004), polar snow (Barrie et al., 1992), mammals (WWF, 2006) and even tree bark (Simonich and Hites, 1995).
     Certain persistent pesticides even accumulate in human tissues and are concentrated as they pass through the links in the food chains. They are implicated in massive deaths of marine mammals (Colborn et al., 1996) and of many bird species (Goldstein et al., 1999). As a result of hormonal