Plant Diversity ›› 2023, Vol. 45 ›› Issue (04): 369-384.DOI: 10.1016/j.pld.2022.09.006

• Articles • Previous Articles     Next Articles

New patterns of the tree beta diversity and its determinants in the largest savanna and wetland biomes of South America

Karla J.P. Silva-Souzaa, Maíra G. Pivatoa, Vinícius C. Silvaa, Ricardo F. Haidarb, Alexandre F. Souzaa   

  1. a. Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, RN, Brazil;
    b. Curso de Engenharia Ambiental, Universidade Federal do Tocantins, TO, Brazil
  • Received:2022-05-10 Revised:2022-09-21 Online:2023-07-25 Published:2023-08-21
  • Contact: Karla J.P. Silva-Souza,
  • Supported by:
    We thank Augusto C. Silva, Gabriela S. Faulhaber, Isabelle Cristina M. Coelho and Luiza S. Cantidio for their help with data entry in the caaporã database. We are grateful to Professor Fernando R. da Silva (UFSCar) who provided the R script for deviance partitioning. We thank José L.A. Silva for the constructive discussions on classification methods that helped in the implementation of the bioregionalization analyses. We are thankful to Carlos S.D. Fonseca, Gustavo B. Paterno, Marcelo F. Moro, Miriam P. Pinto, Vanessa L. Rezende, and Vinícius L. Dantas and three anonymous reviewers for useful comments on earlier versions of the manuscript. This research is registered in the Sistema Nacional de Gestão do Patrimônio Genético e do Conhecimento Tradicional Associado (SISGEN) under code AA38B00. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001.

Abstract: Clear and data-driven bioregionalizations can provide a framework to test hypotheses and base biodiversity conservation. Here we used occurrence and abundance data in combination with objective analytical methods to propose two bioregionalization schemes for tree species of the Cerrado and the Pantanal in South America. We also evaluated the contribution of three sets of determinants of the occurrence- and abundance-based subregions. We compiled data on tree species composition from 894 local assemblages based on species occurrences, and from 658 local assemblages based on species abundances. We used an unconstrained community-level modelling approach and clustering techniques to identify and map tree subregions for the occurrence and the abundance data sets, separately. Hierarchical clustering analyses were conducted to investigate floristic affinities between the subregions and to map broader floristic regions. We used multinomial logistic regression models, deviance partitioning, and rank-sum tests to assess the main subregion correlates. We identified 18 occurrence- and four abundance-based subregions in the Cerrado-Pantanal. The hierarchical classifications grouped the occurrence-based subregions into nine floristic zones and abundance-based subregions into two broad floristic zones. Variation in subregions were explained mainly by environmental factors and spatial structure in both occurrence and abundance data sets. The occurrence- and abundance-based subregions are complementary approaches to disentangle macroecological patterns and to plan conservation efforts in the Cerrado and the Pantanal. Our findings based on occurrence data revealed more complex and interdigitated boundaries between subregions of tree species than previously reported. The environment, historical stability, and human effects act in a synergetic way on the distribution of the subregions. Finally, the relevance of contemporary environmental factors to the subregion patterns we found alert us to the profound impact global warming may have on the spatial organization of the Cerrado-Pantanal tree flora.

Key words: Cerrado, Pantanal, Savanna, Biogeographical regionalization, Biodiversity hotspot, South America