**2. Ecological station**

186 Biodiversity Loss in a Changing Planet

Approximately 40% of this biome has already been completely anthropized for agricultural and livestock activities. Such activities may cause serious damage to the Cerrado such as burning, tree felling for charcoal production. Hoffmann & Jackson (2000) affirmed that the conversion of the natural Savannah in pasture can reduce the precipitation in at least 10%, and to increase the medium temperature of the superficial air in 0.5oC. Those practices usually occur in a disorderly and non-sustainable way (Castro, 1999; Saucer, 1999; Araujo,

Fig. 1. Cerrado biome in Brazil (http://www.wwf.org.br/)

In Piauí state the Cerrado occupies approximately 115,000 km² (larger area of Northeast Brazil), presenting great potential for exploitation. Currently, the state has experienced a rapid occupation and consequently it is estimated that about 10% of this ecosystem have already been occupied by agricultural projects. From the 90's, this process was accelerated by the deployment of mechanized agriculture, especially in grain crops, including soybeans, corn, rice and beans (Araujo, 2005). Agricultural expansion occurs mainly in Southern and Southwestern of Piauí, because they are favoured by stable climate and topography, what consists of large plateaus on the tops of mountains (EMATER, 2009; Funaguas, 2009). The irrational use of this biome is followed by problems such as erosion and the consequent

Burning is the most harmful of all these factors. In drought periods, this phenomenon is a matter of constant concern due to use of passive fire protection products. There are two types of burning causes: natural and anthropic. In the first type, burnings usually occur in

desertification. The last phenomenon has already been detected in this region.

2005).

Currently, environmental problems have received special attention, and there has been much discussion on environmental preservation. The establishment of protected areas, called Conservation Units (CUs) emerges from this discussion. The purpose of these CUs is to protect the flora and fauna, by reducing the negative impacts of human activity on biodiversity. In Brazil, the creation of protected areas was legally established by the Brazilian Forest Code (Decree 23.793 - 1934). The first Ecological Park was created only in 1937 (Sick, 1997).

The Conservation Areas are divided into two major groups: Integral Protection Conservation Units (IPU) and Sustainable Use Conservation Units (SUU). The first group aims to balance nature conservation by promoting its sustainable use. The second goal is to preserve the nature, admitting only the indirect use of its natural resources, except in cases provided by Law. The two groups are subdivided into categories. The Ecological Stations belong to the second group.
