Santana, Mariana Martins Medeiros de; https://orcid.org/0000-0002-5218-7140; http://lattes.cnpq.br/3670187817881634
Resumo:
Changes in natural fire regimes in the Amazon can affect the sustainability of
forests and savannas. However, there is a lack of knowledge about the causal determinants
and the effects of different fire regimes on the biodiversity of ecosystems in northeastern
Amazonia. In addition, there are disagreements about what could happen with fire activity
in future climate change scenarios. This study aimed to: (i) synthesize previous research
efforts in Fire Ecology and Remote Sensing (RS), through scientometric analysis and
connection networks; (ii) model the recent spatial distribution of fire propensity, by the
maximum entropy method (MaxEnt), identifying the main drivers; (iii) project the future
“niche of fire” in two contrasting scenarios of global warming, considering the data from
the CNRM-CM6-1 model for the next decades and for the end of this century; and (iii) to
analyze how different fire recurrences may have affected the structure and diversity
(taxonomic and functional) of savannas, through the interpretation of generalized additive
mixed models (GAMM). The scientometric analyzes allowed us to identify that RS and
Fire Ecology are sciences that evolved over time in a complementary way, contributing
to expand studies in biodiversity, conservation and environmental monitoring. Our fire
probability models have shown that ignition is more common in savannas than forests
due to the synergy of socioeconomic and environmental factors. However, in the long
term, shifts towards a warmer and drier climate could result in a large regional expansion
of fire-prone areas. Finally, we found that in savannas the taxonomic diversity reaches
maximum levels in landscapes under intermediate fire frequency regimes. The increase
in fire frequency may be resulting in the loss of species that play redundant functional
roles and there may still be the entry of new species of grasses and herbs favored by this
disturbance. Therefore, despite not decreasing functional richness, fire modifies
functional diversity. We conclude that at local scales the high frequency of fires reduces
biological diversity, an impact that in the long term may be irreversible, especially if
climate change converges to scenarios of greater global warming.