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No evidence of intrinsic spatial processes driving Neotropical savanna vegetation on different substrates
Author(s) -
Mews Henrique A.,
Pinto José Roberto R.,
Eisenlohr Pedro V.,
Lenza Eddie
Publication year - 2016
Publication title -
biotropica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.813
H-Index - 96
eISSN - 1744-7429
pISSN - 0006-3606
DOI - 10.1111/btp.12313
Subject(s) - floristics , vegetation (pathology) , ecology , abundance (ecology) , tropical savanna climate , threatened species , geography , spatial variability , plant community , substrate (aquarium) , spatial heterogeneity , environmental science , species richness , habitat , biology , ecosystem , medicine , statistics , mathematics , pathology
The relationships between floristic patterns and environmental variation in tropical savannas have been the focus of many studies worldwide. However, important aspects of these relationships, such as the role of geographic distance in structuring plant communities, have received little attention. We investigated the individual and combined influences of substrate, climatic, and spatial factors on the floristic‐structural dissimilarity between two savanna physiognomies in the core region of Brazilian savannas: one on plain relief with deep soils and another on steep relief with shallow rocky soils. Ten 1‐ha plots were sampled in each physiognomy. We modeled species abundance using multiple linear models and variance partitioning. Our results indicated that spatial processes that are intrinsically related to species variation have negligible effects on floristic variation. The most important predictors in our models were related to soil characteristics (mainly nutrient availability) and topography (relief and elevation). Consequently, the substrate component exhibited the greatest power (14%) in explaining the floristic‐structural variation in the overall variance partitioning. Our results provide the first demonstration of the individual and combined contributions of substrate, climatic, and spatial factors to the occurrence and abundance of woody species in the most diverse and threatened savanna in the world. We also provide evidence that neutral processes might not be strong predictors of vegetation structure where savanna substrates differ greatly; instead, community structure may be primarily regulated by environmental filters.