Current and historical climate signatures to deconstructed tree species richness pattern in South America

Matheus De Souza Lima-Ribeiro,Daniel Paiva Silva,Frederico Valtuille Faleiro

doi:10.4025/actascibiolsci.v35i2.14202

Matheus De Souza Lima-Ribeiro, Daniel Paiva Silva + Show 1 more

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https://doi.org/10.4025/actascibiolsci.v35i2.14202

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Abstract

The purpose of this study was to investigate the importance of present and historical climate as determinants of current species richness pattern of forestry trees in South America. The study predicted the distribution of 217 tree species using Maxent models, and calculated the potential species richness pattern, which was further deconstructed based on range sizes and modeled against current and historical climates predictors using Geographically Weighted Regressions (GWR) analyses. The current climate explains more of the wide-ranging species richness patterns than that of the narrow-ranging species, while the historical climate explained an equally small amount of variance for both narrow-and-wide ranging tree species richness patterns. The richness deconstruction based on range size revealed that the influences of current and historical climate hypotheses underlying patterns in South American tree species richness differ from those found in the Northern Hemisphere. Notably, the historical climate appears to be an important determinant of richness only in regions with marked climate changes and proved Pleistocenic refuges, while the current climate predicts the species richness across those Neotropical regions, with non- evident refuges in the Last Glacial Maximum. Thus, this study's analyses show that these climate hypotheses are complementary to explain the South American tree species richness.

Highlights

The understanding on factors that affect species distributions in space and time is an essential issue in Ecology, Evolution, and Conservation Biology (SVENNING et al, 2008)
We investigate two alternative hypotheses for the South American pattern of tree species richness regarding historical and current climate: 1) if South America did not glaciate during the Last Glacial Maximum (LGM) and the lowland species did not isolate in Pleistocenic refuges (COLINVAUX et al, 1996, 2000), current climate will exert a much more stronger effect on species distributions patterns than historical one, independently of the species’ dispersal abilities; 2) We expect that narrow-ranging species richness in South America will be more affected by historical climate than wide-ranging species richness, since the most recent Ice Age caused climate changes worldwide
The forestry tree species richness in South America showed the highest richness in the Southeast of the continent (Figure 1A and Appendix S3J in Supporting Information)

Summary

Introduction

The understanding on factors that affect species distributions in space and time is an essential issue in Ecology, Evolution, and Conservation Biology (SVENNING et al, 2008). Once species are expected to track down suitable areas for their permanence (JETZ et al, 2004), climatically stable areas are expected to be richer in species than unstable ones (ARAÚJO et al, 2008; HAWKINS et al, 2006). Such pattern would be primarily caused by the physiological incapacity of many species to adapt to environmentally unstable places along the evolutionary time, which may imply that only a few species would be able to survive in areas of severe climatic conditions (FRASER; CURRIE, 1996)

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