O objetivo do presente estudo foi avaliar o comportamento do fogo em queimas controladas, com o fim de estabelecer relações entre as variáveis do comportamento do fogo e fatores determinantes de propagação (material combustível e variáveis climáticas). Este trabalho foi desenvolvido em três áreas experimentais e em três períodos do dia de realização das queimas: no horário de 07:00 as 11:00 horas da manhã, no horário de 13:00 as 17:30 horas e de 18:00 as 21:00 horas, nos municípios de Gurupi-TO e Dueré-TO, no mês de junho de 2016. A primeira área, denominada Gurupi I, está distante 3 km do município de Gurupi-TO, com vegetação Andropogon gayanus (altura média de 1,80 cm); a segunda área, denominada Gurupi II, está distante 4 km do município de Gurupi-TO, com Andropogon gayanus (altura média entre 40-60 cm) e a terceira área, denominada Dueré, fica aproximadamente a 40 km do município de Gurupi-TO, com vegetação típica de Cerrado Stricto Sensu. Para a realização da coleta de material combustível, a metodologia empregada foi a de “amostragem destrutiva” que consiste na retirada de todo o material contido no quadrante (1x1 m). O material combustível foi separado em vivo e morto, e por classes diamétricas (< 0,7 cm; 0,7 – 2,5 cm; 2,5 – 7,6 cm; > 7,6 cm). De acordo com as análises estatísticas, Gurupi I foi a área que apresentou maior biomassa de material combustível vivo e morto com diâmetro < 0,7 cm (3,789 t.ha-1; 9,912 t.ha-1). Já na área Dueré, o material combustível vivo e morto com diâmetro <0,7 cm apresentou uma carga de 0,451 t.ha-1; 3,492 t.ha-1 respectivamente. O material combustível morto, com diâmetros > 0,7 cm, foi observado somente na área de Dueré com uma carga total de 0,879 t.ha-1. Com relação aos resultados obtidos em Dueré, a velocidade média do vento variou de 0,0 m.s-1 (período da tarde) a 0,02 m.s-1 (período da noite). Na intensidade do fogo, esta variação ficou entre 118,60 kcal.m-1 s-1 (manhã) e 361,45 kcal.m-1.s-1 (tarde) e a (noite) com a menor intensidade 53,21 kcal.m-1.s-1. Em Gurupi I, com relação à altura das chamas no período da manhã, foi observado o menor valor (1,12 m) e no período da tarde o maior valor (3,47 m). Em Gurupi II, a velocidade média de propagação foi maior nas queimas realizadas no período da manhã (0,02 m.s-1) e da tarde (0,04 m.s-1). A temperatura e a umidade relativa do ar foram, respectivamente, maiores e menores no período da tarde com os seguintes valores: 37,4º C e 17,0%, e apresentaram correlação com os parâmetros de comportamento do fogo e foram incluídas nos modelos matemáticos gerais ajustados para predição da velocidade de propagação (R2 = 0,44); da intensidade do fogo (R2 = 0,60) e da altura das chamas (R2 = 0,74). De forma geral as variáveis que mais exerceram influência no comportamento do fogo foram as variáveis meteorológicas como umidade relativa e temperatura do ar. / The objective of the present study was to evaluate the behavior of fire in controlled burning, in order to establish relationships between fire behavior variables and propagation determinants (combustible material and climatic variables). This work was developed in three experimental areas divided into three periods of the day for the firing of the burns, from 07:00 to 11:00 in the morning, from 13:00 to 17:30 and from 18:00 at 21:00 hours, in the municipalities of Gurupi-TO and Dueré-TO, in June 2016. The first area, called Gurupi I, is 3 km from the municipality of Gurupi-TO, with vegetation Andropogon gayanus (average height of 1.80 cm); The second area, called Gurupi II, is 4 km from the municipality of Gurupi-TO, with Andropogon gayanus (average height between 40-60 cm) and the third area, called Dueré, is approximately 40 km from the municipality of Gurupi-TO, With vegetation typical of Cerrado Stricto Sensu. For the collection of combustible material, the methodology used was the "destructive sampling" used by different authors, which consists of the removal of all the material contained in the quadrant. The combustible material was separated in vivo and dead, and by diametric grades (<0.7 cm, 0.7 - 2.5 cm, 2.5 - 7.6 cm, >7.6 cm). According to the statistical analysis, Gurupi I was the area that presented the largest biomass of living and dead combustible material with a diameter of <0.7 cm (3.789 t.ha-1; 9.912 t.ha-1). In the Dueré area, live and dead fuel with a diameter of <0.7 cm had a load of 0.451 t.ha-1; 3.492 t.ha-1 respectively. The dead fuel material, with diameters> 0.7 cm, was observed only in the Dueré area with a total load of 0.879 t.ha-1. Regarding the results obtained in Dueré, the average wind speed ranged from 0.0 m.s-1 (afternoon period) to 0.02 m.s-1 (night time). In the fire intensity, this variation was between 118.60 kcal.m-1.s-1 (morning) and 361.45 kcal.m-1.s-1 (late) and at (night) with the lowest intensity 53.21 kcal.m-1.s-1. In Gurupi I, the height of the flames in the morning was observed the lowest value (1.12 m) and in the afternoon showed the highest height (3.47 m). In Gurupi II, the average propagation velocity was higher in the morning (0.02 m.s-1) and in the afternoon (0.04 m.s-1). The temperature and relative humidity were respectively higher and lower in the afternoon with the following values: 37.4°C and 17.0%, and presented correlation with fire behavior parameters and were included in the mathematical models General adjusted for propagation velocity prediction (R2= 0.44); of the fire intensity (R2 = 0.60) and the height of the flames (R2 = 0.74). In general, the variables that exerted most influence on fire behavior were the meteorological variables, such as relative humidity and air temperature.

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<p>There has been a long-term decline in number of cyclic vole populations in boreal Sweden since the 1970s. Several hypotheses have been suggested to explain this decline. Commonly for <i>C. glareolus</i>, <i>C. rufocanus</i> and <i>M. agrestis</i>, the decline has followed upon an increased frequency and severeness of winter declines and has shown up as a drop in spring densities. The spring decline is most pronounced for <i>C. rufocanus</i>. In contrast to other voles, <i>C. rufocanus</i> also show a decline in fall densities, suggesting some additional disturbance in this species. Habitat fragmentation has been suggested as such an additional disturbance and in this thesis the effect of habitat fragmentation on <i>C. rufocanus</i> is explored.</p><p>At first the sampling method was evaluated i.e. whether the decline could be due to destructive sampling when the method in use in the long-term monitoring is snap-trapping. This resulted in a rejection of the destructive sampling hypothesis as a possible cause behind the decline in <i>C. rufocanus</i>. Habitat preference revealed that three habitats at the local scale (trap station) were high quality habitats for <i>C. rufocanus</i>: forest of moist and wet/hydric dwarf-shrub type, in addition to forest/swamp complexes rich in dwarf-shrubs. The occurrence of <i>C. rufocanus</i> at the landscape scale was positively correlated with the amount of boulder fields and a low degree of fragmentation of old-growth pine forests. There was considerable local variation in the decline in vole density among the 58 1-ha sampling plots, with respect to both density and timing of the decline, which suggested that habitat destruction outside sampling plots might be involved. Overall, clear-cuts had a negative influence on vole densities at both the local and landscape scale. A multiple regression analysis suggested that having both a high quality habitat at the local scale and a high proximity among xeric-mesic mires and a low connectivity among clear-cuts at the landscape scale were important for the occurrence of <i>C. rufocanus</i>.</p><p>Initial analysis at the landscape scale were based on landscape data collected from 2.5 x 2.5 km areas centred on the individual vole sampling plots. Further investigations, however, on the patch level suggest that focal forest patch size and quality was of major importance in determining occurrence and persistence of <i>C. rufocanus</i>. Although not tested formally in these studies, the habitat fragmentation hypothesis has so far received support. Currently <i>C. rufocanus</i> seems to be affected negatively by too low patch sizes of suitable habitats in the surrounding landscape suggesting that the amount of suitable habitats could already be below the fragmentation threshold. However, this has to be evaluated further. Work is in progress to establish time-series over local landscape changes, and to evaluate if such changes have been associated with local declines of <i>C. rufocanus</i> and whether habitat loss, true habitat fragmentation or both have been influential.</p>

There has been a long-term decline in number of cyclic vole populations in boreal Sweden since the 1970s. Several hypotheses have been suggested to explain this decline. Commonly for C. glareolus, C. rufocanus and M. agrestis, the decline has followed upon an increased frequency and severeness of winter declines and has shown up as a drop in spring densities. The spring decline is most pronounced for C. rufocanus. In contrast to other voles, C. rufocanus also show a decline in fall densities, suggesting some additional disturbance in this species. Habitat fragmentation has been suggested as such an additional disturbance and in this thesis the effect of habitat fragmentation on C. rufocanus is explored. At first the sampling method was evaluated i.e. whether the decline could be due to destructive sampling when the method in use in the long-term monitoring is snap-trapping. This resulted in a rejection of the destructive sampling hypothesis as a possible cause behind the decline in C. rufocanus. Habitat preference revealed that three habitats at the local scale (trap station) were high quality habitats for C. rufocanus: forest of moist and wet/hydric dwarf-shrub type, in addition to forest/swamp complexes rich in dwarf-shrubs. The occurrence of C. rufocanus at the landscape scale was positively correlated with the amount of boulder fields and a low degree of fragmentation of old-growth pine forests. There was considerable local variation in the decline in vole density among the 58 1-ha sampling plots, with respect to both density and timing of the decline, which suggested that habitat destruction outside sampling plots might be involved. Overall, clear-cuts had a negative influence on vole densities at both the local and landscape scale. A multiple regression analysis suggested that having both a high quality habitat at the local scale and a high proximity among xeric-mesic mires and a low connectivity among clear-cuts at the landscape scale were important for the occurrence of C. rufocanus. Initial analysis at the landscape scale were based on landscape data collected from 2.5 x 2.5 km areas centred on the individual vole sampling plots. Further investigations, however, on the patch level suggest that focal forest patch size and quality was of major importance in determining occurrence and persistence of C. rufocanus. Although not tested formally in these studies, the habitat fragmentation hypothesis has so far received support. Currently C. rufocanus seems to be affected negatively by too low patch sizes of suitable habitats in the surrounding landscape suggesting that the amount of suitable habitats could already be below the fragmentation threshold. However, this has to be evaluated further. Work is in progress to establish time-series over local landscape changes, and to evaluate if such changes have been associated with local declines of C. rufocanus and whether habitat loss, true habitat fragmentation or both have been influential.