**1. Introduction**

184 Biodiversity Loss in a Changing Planet

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Population declines and priorities for amphibian conservation in Latin America. *Conservation Biology*, Vol. 15, No 5 (October, 2001) pp. 1213–1223. ISSN: 1526-4629. Zachos J., M. Pagani, L. Sloan, E. Thomas & K. Billups 2001. Trends, Rhythms, and

Aberrations in Global Climate 65 Ma. to Present. *Science* Vol. 292; No 5517 (April,

The degradation of the soil and native ecosystems and the dispersion of exotic species are the largest threats to the biodiversity. Brazil is considered one of the most biodiversity countries in the world, where it is concentrated about 10% of whole terrestrial biota (Mittermeier et al., 1997). Studies have shown that the Brazilian diversity was already greater than is recorded nowadays. Even with the disappearance of species, the biodiversity of the Cerrado is still quite expressive and notable. Depending on the taxonomic group, 20 to 50% of species occurring in the Brazilian Cerrado.

The great diversity of species of animals and plants of the Cerrado is associated with spatial heterogeneity (the variation of ecosystems over space) of this biome, which allows the coexistence of different physiognomic forms in the same region. The variation of environments makes possible species of animals and plants present a strong association with local ecosystems, being closely tied to natural environments, such as the *Antilophia galeata* which are found only in gallery forests, and the *Mauritia flexuosa* that are closely associated with the paths. This relation fauna-flora-Cerrado illustrates the importance of maintaining of the natural vegetable covering of this biome, as a basic strategy for maintaining biological diversity expressive.

Recent studies indicate that a loss up to 25% of bird species associated with the gallery forest of the Cerrado may occur, just if there is the destruction of natural environments to the neighboring woods, even though it remains untouched (Machado, 2000; Machado et al ., 2004). Furthermore, excessive reduction of native areas will cause the extinction of species from fragments of small size (Hass, 2002).

The Cerrado is a biome originally covered by vegetation ranging from grassland (country) to *Cerradão* and has two well-defined seasons: dry winter and rainy summer. This biome shelters deciduous species and presents a nutrient-poor acidic soil with high iron and aluminum content. According to Eiten (1979), the Cerrado vegetation varies from sparse trees to dense forest vegetation. The variation in the Cerrado physiognomies has been attributed to the action of fire, soil factors (Eiten, 1972; Coutinho, 1978; Rizzini, 1979), topography and water (Furley & Ratter, 1988).

The Cerrado biome is the second largest biogeographic region of Brazil covering an area of 2,036,448.00 km² (Fig. 1), around 23% of the national territory (Ratter et al., 1997).

Identification and Analysis of Burned Areas in Ecological Stations of Brazilian Cerrado 187

areas of dry vegetation, leading to devastating fires; anthropogenic burnings, in turn, may

In Brazil, the main causes of burning in the Cerrado were due to improper use of fire equipment. Some pre-fire characteristics of ecological fires (Whelan, 1997) are not detected at the moment of the burning, as the firebreaks construction, the checking of climatic conditions and of the appropriate period, as well as the availability of fire control equipment. Additionally, criminal fires are frequent, which are caused by the action of

Great burnings may present serious risks for the conservation of the biodiversity and maintenance of ecological processes. These fires are particularly dangerous in small areas, which present rare species and/or species susceptible to extinction, which are usually very sensitive to the fire. This is the case of most Conservation Units (UC) in Brazil, including the Ecological Stations (ES) where many species are at risk of population decline because of

The geographical location of the fires within an ecological station can be used in strategies to fight fires in this area. A technique that has proven to be efficient is satellite monitoring (Cihlar et al., 1997; Carvalho, 2001; Remmel & Perera, 2001). The relatively low cost and the possibility of easily obtaining digital images have stimulated research on the theme. In digital, orbital or aerial, images it is possible to identify forest fires. Also, by temporary analysis, it is possible to

In this paper, a multi-temporary series of images of the Landsat 5 (American satellite) was used in the location and dimension of burned areas. Those images cover the area of the Uruçuí-Una Ecological Station (UUES) located in southern Piauí state / Brazil (approximate central coordinate: Latitude 8o52' and Longitude 45o12' South). The purpose of this study is to investigate the locations and frequencies of burnings, as well as the type of vegetation damaged by fires, besides analyzing if there is influence of the El-Niño and the La-Niña phenomena.

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

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

The Uruçuí-Una Ecological Station (UUES), with a total area exceeding 1,300 square kilometers, was established in 1981 with the purpose of protecting and preserving fragments

of Cerrado ecosystems and promoting the development of scientific research.

(Decree 23.793 - 1934). The first Ecological Park was created only in 1937 (Sick, 1997).

characterize the previous types of vegetations that were destroyed by fires.

occur in any type of vegetation (Eiten, 1972; Coutinho, 1978).

arsonists, hunters, fishermen and balloons (Medeiros, 2002).

these factors (Dias, 1998).

**2. Ecological station** 

belong to the second group.

**2.1 Uruçui-Una ecological station** 

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, 2005).

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

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 areas of dry vegetation, leading to devastating fires; anthropogenic burnings, in turn, may occur in any type of vegetation (Eiten, 1972; Coutinho, 1978).

In Brazil, the main causes of burning in the Cerrado were due to improper use of fire equipment. Some pre-fire characteristics of ecological fires (Whelan, 1997) are not detected at the moment of the burning, as the firebreaks construction, the checking of climatic conditions and of the appropriate period, as well as the availability of fire control equipment. Additionally, criminal fires are frequent, which are caused by the action of arsonists, hunters, fishermen and balloons (Medeiros, 2002).

Great burnings may present serious risks for the conservation of the biodiversity and maintenance of ecological processes. These fires are particularly dangerous in small areas, which present rare species and/or species susceptible to extinction, which are usually very sensitive to the fire. This is the case of most Conservation Units (UC) in Brazil, including the Ecological Stations (ES) where many species are at risk of population decline because of these factors (Dias, 1998).

The geographical location of the fires within an ecological station can be used in strategies to fight fires in this area. A technique that has proven to be efficient is satellite monitoring (Cihlar et al., 1997; Carvalho, 2001; Remmel & Perera, 2001). The relatively low cost and the possibility of easily obtaining digital images have stimulated research on the theme. In digital, orbital or aerial, images it is possible to identify forest fires. Also, by temporary analysis, it is possible to characterize the previous types of vegetations that were destroyed by fires.

In this paper, a multi-temporary series of images of the Landsat 5 (American satellite) was used in the location and dimension of burned areas. Those images cover the area of the Uruçuí-Una Ecological Station (UUES) located in southern Piauí state / Brazil (approximate central coordinate: Latitude 8o52' and Longitude 45o12' South). The purpose of this study is to investigate the locations and frequencies of burnings, as well as the type of vegetation damaged by fires, besides analyzing if there is influence of the El-Niño and the La-Niña phenomena.
