Patterns of floristic distribution in the semiarid brazilian
Caatinga, floristic composition, species distribution, environmental
gradient and semi-arid region.
The floristic composition of communities is not an overlap of distributions, but the
result of the interaction between various factors. Hutchinson's niche concepts are part of
the understanding of species distribution. However, consider the distributions and their
associated variables as homogeneous is an error, since the environmental heterogeneity
is one of the competences for diversity and processes of a biological community. As
well as thinking that individuals, their life strategies and environment are unchanging
over time. The understanding of the distribution of species also permeates the concept
of environmental filter with its biotic (ecological interactions) and abiotic
(environmental restrictions). The objective of this work was to find the distribution
patterns of trees and if they are more associated to edaphic or climatic variables, using
as test area the Caatinga - northeastern Brazil. A study area was the Caatinga, about 800
thousand Km2, with points distributed throughout its length. A database was assembled
from data from the literature where information on the studied sites, biotic and abiotic
variables and species listing were collected. A check of the duplicates and taxonomic
correction of the species was made, in the end we had a total of 2666 tree species. After
removal of the points with extreme richness and as well as analyzes with a total of 241
points. We are concluding as statistical analyzes, that the PCoA for verification of
floristic gradients, the Moran’s index for verification of spatial correlation, and a
regression as variables collected and our gradients. To perform as analysis, the RStudio
Program is being used with the specific packages required for each of the differences.