Banca de DEFESA: MICAEL FELIPE DE MORAES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : MICAEL FELIPE DE MORAES
DATA : 19/07/2024
HORA: 09:00
LOCAL: Google Meet
TÍTULO:

PHYTOGEOGRAPHY AND PHYLOGENIC VARIATION OF TREE TAXONS IN AREAS OF THE BRAZILIAN AMAZON BASIN INFLUENCED BY HYDROELECTRIC DAMS

PALAVRAS-CHAVES:

Dams, Ecosystems, Floristics, Refuge, Local factors, Phylogeny, Lineage diversity.

PÁGINAS: 86
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
SUBÁREA: Ecologia de Ecossistemas
RESUMO:

Hydroelectric dams impact the structure and functioning of riverine ecosystems, and the ecological character of species reflects the biogeographic history of their ancestors. The objectives of this study were to investigate the floristic relationships and variation in tree diversity and phylogenetic structure among riverine ecosystems associated with hydroelectric dams built in the Brazilian Amazon, as well as to understand the importance of environmental predictors on variation in tree composition, richness, and metrics that describe the phylogenetic parameters of these areas. We reviewed the main online databases in order to access the floristic lists of studies conducted in the area of influence of hydroelectric dams in the period after the start of operation. We consulted several platforms that incorporate information on climate, soil, and topography to obtain environmental variables with a spatial resolution of 1 km. Based on the regional database composed of 1,178 tree species, we generated a phylogenetic tree using the "V.PhyloMaker" package. We calculated measures of phylogenetic diversity (PD) and phylogenetic structure (MPD – Mean Pairwise Distance and MNTD – Mean Distance to the Nearest Taxon), as well as their corresponding periods ses.PD, ses.MDP and ses.MNTD. We used the generalized least squares (GLS) method to test the effect of environmental variables on phylogenetic metrics. We found that floristic variation among different ecosystems in the Amazon Basin affected by hydroelectric dams is conditioned by the synergistic action of environmental predictors and spatial filters, so that geographically closer sites were more similar in terms of tree species composition. Local environmental factors were determinants in the community assembly process, among which we highlight aridity, elevation, slope orientation (east and north), precipitation in the coldest quarter and presence of coarse fragments in the soil. Furthermore, areas adjacent to rivers interrupted by hydroelectric dams exhibited a pattern of clustered and coded communities. ses.MPD was higher for the Balbina area compared to the Teles Pires and Tucuruí areas. MNTD was higher in Balbina than in Teles Pires, but phylogenetic diversity (PD) was higher in Teles Pires than in Balbina and Jirau. Furthermore, we noticed that the soil variables were the ones that most correlated with ses.PD, ses.MPD and ses.MNTD. Surprisingly, ses.PD decreases along the distance gradient from the main drainage source, revealing that the areas closest to the river harbor a greater diversity of tree lineages. Through the predictors selected by the model and the intrinsic characteristics of the plants associated with the dams, we suggest that when there are restrictions to colonize the higher altitudes seeking refuge against the anoxic conditions of the flood filter, they need to transport the slope barrier and, upon reaching the higher altitudes, deal with the rockiness typical of shallower soils. We suggest that dams be avoided in large, low-lying degraded areas in order to reduce the mortality of species that are intolerant to the stress caused by flooding, and that government forces explore alternative energy sources. The time of exposure of our communities to the disturbance is probably insufficient to have caused major changes in the phylogenetic structure and diversity, but these impacts may be seriously felt in the long term.

MEMBROS DA BANCA:
Interno - 253812001 - PEDRO VASCONCELLOS EISENLOHR
Interna - 986.188.651-68 - SIMONE MATIAS DE ALMEIDA REIS - UNEMAT
Externa ao Programa - 82319001 - SOLANGE APARECIDA ARROLHO DA SILVA
Externo à Instituição - EVERTON ALVES MACIEL - UNICAMP
Externo à Instituição - MARCELO BRILHANTE DE MEDEIROS - EMBRAPA