**6. Results and discussion**

192 Biodiversity Loss in a Changing Planet

the geodetic coordinates are recorded and the information of the vegetation physiognomy is collected in the neighborhood within a radius of approximately 200 meters. This information is stored as data points and then interpolated to other points on the area.

Information on the vegetation is superimposed on burned areas, which are generated from the NDVI and IR, to measure and record biodiversity losses. The overlapping or crossing of

Finally, the results of all the experiments are assessed in relation to the climatic phenomena El-Niño and La-Niña, in order to determine whether or not these phenomena have influence on burnings. This analysis is done by checking the size of the burned area and the behavior of weather phenomena in the analyzed year. According to CPC (2010), the occurrence of the

The quarterly values of the indices corresponding to the occurrence of El Niño and La Niña are graphically plotted (Fig. 6), in order to describe the behavior of these phenomena over time. The period represented on the graph varies between the years 1982 and 2010. Each year is punctuated by twelve quarters that overlap each other, for example, JFM (January, February and March) is the first quarter; the second is FMA (February, March and April);

Fig. 6. El Niño and La Niña based in limit of ±0.5 °C for the Oceanic Niño Index

Additionally, a photographic record is made at each point, e. g. in Fig. 5.

this information is performed using routines developed in MatLab2007a.

Fig. 5. Photographic record of local vegetation

climatic phenomenon can be represented by indexes.

**5.5 Behavior of climatic phenomena** 

The constants used in this study are presented below. In the image registration procedure, the largest root mean square error (RMS) measured was 0.48 pixel. The values used for thresholds T and T1 in the identification of burned areas were 0.4 and 80, respectively. The structuring element B used in "opening" operation is the disc of radius 5. Essentially, opening removes small objects/noises (<5 pixels). The side effect is the elimination of the edges to round the objects. Although the burned areas may be partially (large areas) or totally (small areas) eliminated by the opening, this technique is very effective to eliminate noise. In Fig. 7 is shown an example in image IR-1989.

Fig. 7. Points eliminated by the opening operation.

Several points detected as burning alone (Fig. 7a) were removed by opening operation (Fig. 7b). The circles exposed in Fig. 7a show concentration of these points (noise), what were eliminated with the application of that technique morphology.

The burned areas identified in the Landsat 5 TM images, concerning the nine years analyzed, can be seen in Fig. 8.

Visually, it can be inferred that in 1985 there were few fires, which were more frequent across the borders of the UUES area. One possible explanation is that some areas of the UUES are inhabited, and burning is used for the practice of subsistence farming. In the following years (1987, 1989 and 1996) an abrupt expansion of the burned areas was observed, although with a small decline between 1996 and 1998. According to members of ICMBio, this increase was due to the advent of intensive agriculture and the absence of fire-

Identification and Analysis of Burned Areas in Ecological Stations of Brazilian Cerrado 195

The peak that occurred in 1996 shows that 37.40% of the UUES area was reached by fire, which is more than the index measured (37.18%) for the sum of the burned areas in all the other years except for 1998 and 2007. The areas least affected by fires in 1985 and 2000 were 8.59 and 43.33 km2, respectively. Fig. 10 shows that 67.25% (black area) of the UUES area

*In loco* observation showed that most burned areas correspond to the physiognomies of *cerrado sensu stricto*, especially in upland areas (plateaux). Only one of the study areas was classified as *campo cerrado*. The areas located in the bottom (valley), which were also affected by fires corresponded to *cerrado stricto sensu anthropic*. According to Medeiros & Cunha

Fig. 9. Graphic representation of the measures of the burned areas

was reached by fire in at least one of the years analyzed.

Fig. 10. Total area affected by fire in years analyzed.

fighting groups close to UUES in that period. In the 2000s, the fire brigades fought the fires in the area. Besides, climatic factors must be taken into consideration. However, they shall be discussed later.

For a quantitative analysis, all the areas were measured in square kilometers and represented graphically, as shown in Fig. 9.

Fig. 8. Forest fires happened in the analyzed years

fighting groups close to UUES in that period. In the 2000s, the fire brigades fought the fires in the area. Besides, climatic factors must be taken into consideration. However, they shall

For a quantitative analysis, all the areas were measured in square kilometers and

1985 1987 1989

1996 1998 2000

2007 2008 2010

Fig. 8. Forest fires happened in the analyzed years

be discussed later.

represented graphically, as shown in Fig. 9.

Fig. 9. Graphic representation of the measures of the burned areas

The peak that occurred in 1996 shows that 37.40% of the UUES area was reached by fire, which is more than the index measured (37.18%) for the sum of the burned areas in all the other years except for 1998 and 2007. The areas least affected by fires in 1985 and 2000 were 8.59 and 43.33 km2, respectively. Fig. 10 shows that 67.25% (black area) of the UUES area was reached by fire in at least one of the years analyzed.

Fig. 10. Total area affected by fire in years analyzed.

*In loco* observation showed that most burned areas correspond to the physiognomies of *cerrado sensu stricto*, especially in upland areas (plateaux). Only one of the study areas was classified as *campo cerrado*. The areas located in the bottom (valley), which were also affected by fires corresponded to *cerrado stricto sensu anthropic*. According to Medeiros & Cunha

Identification and Analysis of Burned Areas in Ecological Stations of Brazilian Cerrado 197

number of fires that occurred in that year. The El-Niño climatic phenomenon occurred in the 1985-1987 period. Consequently, the graph of Fig. 9 shows an increase in the burned areas. Between 1987 and 1989 a transition from El-Niño to La-Niña was seen, with La Niña prevailing most of the time. The total amount of burned areas remained almost constant, with a slightly positive trend. Soon after, in a longer period (1989 to 1996) a predominance of El-Niño was observed, which corresponds to the period when the largest areas were destroyed by fires, being consistent with the heating caused by the phenomenon. Although smaller than the previous period, the size of the burned areas between 1996 and 1998 was relatively large, in agreement with the peak of El-Niño in Fig. 6. Cooling happened in the subsequent period (1998-2000) coinciding with the abrupt decrease in the total burned area. Despite a weak intensity the El-Niño phenomenon prevailed in the 2000–2007 interval. Hence, the curve of the area showed again a positive trend. In the last two intervals of time analyzed the consistency of reduction of the burned area in the period of La-Niña (2007- 2008) was maintained and there was an increase in the El-Niño phenomenon (2008-2010).

**Years 1987 1989 1996 1998 2000 2007 2008 2010**  0.93 1.33 3.55 1.82 0.35 0.89 0.22 1.57 25.12 54.41 28.15 7.07 26.85 3.18 18.57 66.10 78.02 4.27 31.68 4.75 24.79 135.25 11.19 75.73 36.07 15.85 6.40 77.25 20.06 57.14 4.46 2.48 2.54 0.15 21.92 **2008** 0.23

It is assumed that there is increased incidence of fires during the El-Niño phenomenon and that the opposite occurs during La-Niña. During the El-Niño periods there is an increase in temperature, which causes the vegetation to dry, favoring the fast propagation of the fire. On the other hand, during the La-Niña phenomenon, cooling is more frequent, which increases the intensity of rains, helping eliminate the fires. Thus, the two graphs (Fig. 6 and Fig. 9) show the existence of this correlation between the climatic phenomena and the

The findings of the present study allow inferring the intensity, distribution form, location and cause of the fires that took place in the Uruçuí-Una Ecological Station (UUES), as well as the biodiversity loss provoked by these fires. Additionally, it is possible to infer the

In agreement with the results obtained, the Landsat 5 TM images were found to be useful in the analyses of fires in CUs, especially due to the collection frequency and quality

The burned locations were correctly defined in the proposed method. They were located so much the burned areas individualized by year, as the total area reached by fire in the

influence of the climatic phenomena El-Niño and La-Niña on the occurrence of fires.

Table 1. Burned areas (km2) coincide with each other

intensity of burned areas in UUES.

spectral/spatial of the data.

**7. Conclusion** 

(2006), the dominant vegetation in the Ecological Station of Uruçui-Una is really the *cerrado strict sensu*.

It is known that depending on the intensity and frequency, forest fires may cause severe damage to the vegetation. However, during the *in loco* visit it was found that the vegetation in some areas was at an advanced stage of regeneration, indicating resilience. Fire is an important factor in maintaining biodiversity, since while some species are affected by fires, others may be benefited in the process of germination and dormancy break of seeds. Thus, the frequency of fires in UUES may be the cause of the predominance of the two existing physiognomic forms. If the germination of tree species is prevented from occurring because of periodic fires, there is a decrease in the density of trees in the region, which leads to a change in the *cerrado sensu amplo* forest landscape, with a larger concentration of trees.

Analysis of fire recurrence (Fig. 11) was carried out in areas adjacent to the checkpoint that characterized the physiognomic form *campo cerrado*. In this region, biodiversity loss is apparent (Fig. 5). Considering the combined damage of fauna and flora, this loss is still more serious.

The area of recurrence of fires presented in Fig. 11 measures 9.53 km2. The measure of this area was determined in the intersection of the burned areas for the years 1978, 1989, 1996 and 1998. Since the burned areas coincided in only two years, a considerable variation occurs depending on the pairs of years analyzed. Table 1 shows this variation.

Fig. 11. Areas of recurrence of fires in period 1978-1998

All the indexes for the year 1985 are low due to the small extent and sparse spatial distribution of the burned areas. 1996, on the contrary, as the year with the largest area of intersection with another year, especially the 1996-1998 pair, which had an area of intersection of 135.25 km2. The intersection of burned areas in 1996 was due to the spatial extension and homogeneity of the area.

Analysis of the graphs of Figs. 6 and 9 shows that the La-Niña climate phenomenon has started two years before 1985. This phenomenon may also have contributed to the reduced number of fires that occurred in that year. The El-Niño climatic phenomenon occurred in the 1985-1987 period. Consequently, the graph of Fig. 9 shows an increase in the burned areas. Between 1987 and 1989 a transition from El-Niño to La-Niña was seen, with La Niña prevailing most of the time. The total amount of burned areas remained almost constant, with a slightly positive trend. Soon after, in a longer period (1989 to 1996) a predominance of El-Niño was observed, which corresponds to the period when the largest areas were destroyed by fires, being consistent with the heating caused by the phenomenon. Although smaller than the previous period, the size of the burned areas between 1996 and 1998 was relatively large, in agreement with the peak of El-Niño in Fig. 6. Cooling happened in the subsequent period (1998-2000) coinciding with the abrupt decrease in the total burned area. Despite a weak intensity the El-Niño phenomenon prevailed in the 2000–2007 interval. Hence, the curve of the area showed again a positive trend. In the last two intervals of time analyzed the consistency of reduction of the burned area in the period of La-Niña (2007- 2008) was maintained and there was an increase in the El-Niño phenomenon (2008-2010).


Table 1. Burned areas (km2) coincide with each other

It is assumed that there is increased incidence of fires during the El-Niño phenomenon and that the opposite occurs during La-Niña. During the El-Niño periods there is an increase in temperature, which causes the vegetation to dry, favoring the fast propagation of the fire. On the other hand, during the La-Niña phenomenon, cooling is more frequent, which increases the intensity of rains, helping eliminate the fires. Thus, the two graphs (Fig. 6 and Fig. 9) show the existence of this correlation between the climatic phenomena and the intensity of burned areas in UUES.
