Publication Date:
2024-03-31
Description:
Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both
young and ancient, than any other biogeographic region. Previous studies have shown
that tree lineages colonized multiple edaphic environments and dispersed widely
across Amazonia, leading to a hypothesis, which we test, that lineages should not be
strongly associated with either geographic regions or edaphic forest types.
Location: Amazonia.
Taxon: Angiosperms (Magnoliids; Monocots; Eudicots).
Methods: Data for the abundance of 5082 tree species in 1989 plots were combined
with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's
eigenvector maps (MEM) to test and quantify the separate and joint contributions of
spatial and environmental variables to explain the phylogenetic composition of plots.
We tested the indicator value of lineages for geographic regions and edaphic forest
types and mapped associations onto the phylogeny.
Results: In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique
evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with
79% of that variation being spatially structured (R2= 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial
spatial patterns not related to the environmental variables we quantified (R2= 28%).
A greater number of lineages were significant indicators of geographic regions than
forest types.
Main Conclusion: Numerous tree lineages, including some ancient ones (〉66 Ma),
show strong associations with geographic regions and edaphic forest types of
Amazonia. This shows that specialization in specific edaphic environments has played
a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore,
many lineages, even those that have dispersed across Amazonia, dominate within a
specific region, likely because of phylogenetically conserved niches for environmental
conditions that are prevalent within regions.
Keywords:
community assembly
;
dispersal limitation
;
environmental selection
;
evolutionary principal
;
component analysis
;
indicator lineage analysis
;
Moran's eigenvector maps
;
neotropics
;
Niche
;
conservatism
;
tropical rain forests
Repository Name:
National Museum of Natural History, Netherlands
Type:
info:eu-repo/semantics/article
Format:
application/pdf
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