**1. Introduction**

22 Biodiversity Conservation and Utilization in a Diverse World

scales. Biol. Conserv. 142: 964–973.

2(26): 169–184. (in Polish)

Environment-Rural Area 10, 4(32): 249–263. (in Polish)

issue2/art-22.html

Sobkowicz P., Podgórska-Lesiak M. 2007. Experiments with crop mixtures: interactions, designs and interpretation. EJPAU 10, 2, #22. http://www.ejpau.media.pl/volume10/

Symonides E. 2010. The role of ecological interactions in the agricultural landscape. Water-

Szempliński W., Budzyński W. 2011. Cereal mixtures in polish scientific literature in the

Thiere G., Milenkovski S., Lindgren P.-E., Sahlén G., Berglund O., Weisner S.E.B. 2009. Wetland creation in agricultural landscapes: Biodiversity benefits on local and regional

Tsitsilas A., Stuckey S., Hoffmann A.A., Weeks A.R., Thomson L. J. 2006. Shelterbelts in agricultural landscapes suppress invertebrate pests. Aust. J Exp. Agr. 46(10): 1379–1388. Walker M.P., Dover J.W., Sparks T.H., Hinsley S.A. 2006. Hedges and green lanes:

Wasilewski Z. 2009. Present statut and directions of grassland management according to the requirements of the common agricultural policy. Water-Environment-Rural Area 9,

period 2003-2007. Review article. Acta Sci. Pol., Agricultura 10(2): 127–140.

vegetation composition and structure. Biodivers. Conserv. 15, 8: 2595–2610.

One quarter of the terrestrial surface is composed of cultural systems, while in the tropics, 70% of the land has already been converted into pastures, agriculture, or a mixture of managed landscapes [1,2]. Agricultural expansion is recognized as the most significant human alteration of the global environment, with the addition of fertilizers in the agricultural sector accounting for high input of nitrogen and phosphorus in terrestrial ecosystems. The conversion of natural ecosystems in agricultural areas has increased fire frequency, and caused profound rupture in nutrient cycles. Furthermore, agricultural expansion has modified landscapes, making them more vulnerable to invasion by exotic species.

In spite of these facts, there is enough evidence that anthropogenic systems managed using agroecological principles can support high levels of biodiversity [3,4], contribute to the maintenance of a healthy environment and its services, as well as depend less on costly external inputs of pollutant pesticides and fertilizers [5]. Therefore, there is a wide range of agricultural management strategies, and they differ greatly on their effect on biodiversity.

Today, agroforestry systems cover more than 16 million hectares, and they involve 1.2 billion people worldwide [6]. Traditional shade-cocoa [7], shade-coffee [3], and agroforestry home-gardens [8] are examples of agricultural systems that retain part of the natural habitat structure and ecosystems properties, providing habitat for rich and diverse fauna and flora including threatened and endemic species. On the other hand, intensive agricultural systems, such as pastures and extensive mono specific plantations, harbour low levels of biodiversity, hamper biological flux, and lead to soil leaching, and nutrient import/export. Intensive agriculture is one of the major drivers of change in some biogeochemical cycles

© 2012 Goulart et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2012 Goulart et al., licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

such as nitrogen and phosphorus [9]. This "out of farm" nutrient input changes the coexistence and competition patterns between autotrophic organisms, changing the structure of natural ecosystems. The more intensive the agricultural systems, the less they are capable of harbouring biodiversity, maintaining landscape connectivity, and conserving ecosystems properties and services. Agricultural intensification is a process in which lowinput agriculture (such as traditional mixed farming) becomes intensified in terms of input/output level, which in turn impacts negatively the associated biodiversity, and the natural ecological services.

Agricultural SystemS and the Conservation of Biodiversity and Ecosystems in the Tropics 25

should go in the direction of establishing human-free reserves as large as possible to avoid species loss. What some ecologists and conservation biologists ignore is the fact that: even supposedly untouched places have actually moderate degree of human intervention [15]. Human-modified ecosystems vary greatly in their quality for biodiversity and maintenance of ecosystems properties. In the 'unaltered' habitat, biodiversity is often restricted to patches embedded in an anthropogenic matrix, which can serve as a conduit or barrier to species movement. Because connectivity is necessary for the long term maintenance of species in patchy landscapes [16], matrix management has deep effects on biodiversity, and functioning of the complex habitat mosaic [17,18]. Finally, human activities can reach far beyond anthropogenic environments, causing changes in several regional processes, hence

On the other hand, agricultural sciences are rarely aware of the effect of management on ecological patterns taking place in the agrienvironments and landscapes. The inverse is also true: they are unaware of how ecological patterns taking place in the agrienvironment and of the landscape affect agricultural production. Agribusiness and agricultural scientists generally aim at reaching the highest agricultural yields. There is an implicit assumption that the loss of ecosystems services will be overcome by biotechnological advances. It is common the thinking that if the weather is drier because of climatic alterations, resistant crop will be developed; that if soil is leached, higher fertilizer quantities can be applied; and

A common argument, in which yield-maximization is based, is the poverty and hunger alleviation issue. The mostly accepted ideas are that agricultural managements should increase production at any cost, based on the hunger alleviation argument, and that conservation efforts, although being relevant to society, should never prevent food production from increasing. Facing these persuasive arguments, biological conservation is regarded as low priority, compared to productivist sectors in the stakeholder's agenda.

Even some conservation biologists accept such assumptions, so that they propose that agricultural areas should reach maximum yields in order to reduce the need to convert more natural areas into agricultural systems, but still maintain the production target [19,20]. This theory is called Land Sparing, and predicts that agricultural intensification would reduce deforestation by increasing productivity. This view has been criticized on the theoretical ground [13,14,21], as well as with empirical data from studies at both regional [22], and local scales [23]. For example, the agricultural product demand (mainly meat and soybean) has increased Amazonian ecosystems' conversion rates. Direct forest conversion into agricultural lands in 2003 accounted for 23% of forest and savannah deforestation in the Mato Grosso state of Brazil. While grazing areas remain the main deforestation cause in the Amazon, land conversion for the production of soybean crops for exportation is also leading

Figure 1A. shows that, at global levels, food production has been steeply increasing since the sixties [25]. Food production per capita has also increased, although at lower rates, and food prices have been declining with some oscillation. Finally, the number of undernourished

affecting ecosystems and biodiversity at larger scales.

so on.

to high deforestation rates [24].
