Neotropical mammal responses to forest fires in Serra do Amolar, Brazil

The increasing frequency and severity of human-caused fires likely have
deleterious effects on species distribution and persistence. In 2020,
megafires in the Brazilian Pantanal burned 43% of the biome’s unburned
area and resulted in mass mortality of wildlife. We investigated changes
in habitat use or occupancy for an assemblage of eight mammal species in
Serra do Amolar, Brazil, following the 2020 fires using a pre- and
post-fire camera trap dataset. Additionally, we estimated density for two
naturally marked species, jaguars Panthera onca and ocelots Leopardus
pardalis. Of the eight species, six (ocelots, collared peccaries Dicotyles
tajacu, giant armadillos Priodontes maximus, Azara’s agouti Dasyprocta
azarae, red brocket deer Mazama americana, and tapirs Tapirus terrestris)
had declining occupancy following fires, and one had stable habitat use
(pumas Puma concolor). Giant armadillo experienced the most precipitous
decline in occupancy from 0.431 ± 0.171 to 0.077 ± 0.044 after the fires.
Jaguars were the only species with increasing habitat use, from 0.393 ±
0.127 to 0.753 ± 0.085. Jaguar density remained stable across years (2.8 ±
1.3, 3.7 ± 1.3, 2.6 ± 0.85 / 100km2), while ocelot density increased from
13.9 ± 3.2 to 16.1 ± 5.2 / 100km2. However, the low number of both jaguars
and ocelots recaptured after the fire period suggests that immigration may
have sustained the population. Our results indicate that the megafires
will have significant consequences for species occupancy and fitness in
fire affected areas. The scale of megafires may inhibit successful
recolonization, thus wider studies are needed to investigate population
trends.

人为引发的野火发生频率与烈度持续攀升，大概率会对物种分布及种群存续产生负面影响。2020年，巴西潘塔纳尔湿地的特大野火（megafires）烧毁了该生物群系43%的未燃区域，造成了大量野生动物死亡。
本研究依托火灾前后的红外相机诱捕（camera trap）数据集，针对巴西Serra do Amolar地区的8种哺乳动物类群，探究了2020年野火过后其栖息地利用模式与种群占用率的变化。此外，我们还对两种天然具有斑纹标识的物种——美洲豹（Panthera onca）与虎猫（Leopardus pardalis）的种群密度进行了估算。
在这8个物种中，6个类群的栖息地占用率在野火后出现下降，分别为虎猫、领西貒（Dicotyles tajacu）、大犰狳（Priodontes maximus）、阿氏刺豚鼠（Dasyprocta azarae）、赤短角鹿（Mazama americana）以及南美貘（Tapirus terrestris）；另有1个类群的栖息地利用模式保持稳定，即美洲狮（Puma concolor）。其中大犰狳的栖息地占用率下降幅度最为剧烈，从火灾前的0.431 ± 0.171降至火灾后的0.077 ± 0.044。
美洲豹是唯一出现栖息地占用率上升的物种，从0.393 ± 0.127升至0.753 ± 0.085。美洲豹的种群密度在各年间保持稳定（分别为2.8 ± 1.3、3.7 ± 1.3、2.6 ± 0.85 只/100km²），而虎猫的种群密度则从13.9 ± 3.2 只/100km²升至16.1 ± 5.2 只/100km²。
不过，野火后被重新捕获的美洲豹与虎猫个体数量较少，这表明种群的存续可能依赖于外来个体的迁入。
本研究结果表明，特大野火会对受影响区域的物种栖息地占用率与生存适合度产生显著影响。当前特大野火的蔓延规模或会阻碍物种成功重新拓殖，因此需要开展更大范围的研究以探究种群动态趋势。