Recovering species demographic history from multi-model inference: the case of a Neotropical savanna tree species

Abstract

BackgroundGlaciations were recurrent throughout the Quaternary and potentially shaped species genetic structure worldwide by affecting population dynamics. Here, we implemented a multi-model inference approach to recover the distribution dynamics and demographic history of a Neotropical savanna tree, Tabebuia aurea (Bignoniaceae). Exploring different algorithms and paleoclimatic simulations, we used ecological niche modelling to generate alternative hypotheses of potential demographic changes through the last glacial cycle and estimated genetic parameters using coalescent modelling.ResultsComparing predictions from demographic hypotheses with genetic parameters of modern populations, our findings revealed a likely scenario of population decline, with spatial displacement towards Northeast Brazil from the last glacial maximum to the mid-Holocene. Subsequently, populations expanded in response to the return of the climatically suitable conditions in Central-West Brazil. Nevertheless, a wide historical refugium across Central Brazil likely maintained large populations connected throughout time. The expected genetic signatures from such predicted distribution dynamics are also corroborated by spatial genetic structure observed in modern populations.ConclusionBy exploring uncertainties inherent in multiple working hypotheses, we have shown that multi-model inference is a fruitful and efficient approach to recover the nature, timing and geographical context of the Tabebuia aurea population dynamic in response to the Quaternary climate changes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-014-0213-0) contains supplementary material, which is available to authorized users.

A large historical refugium explains spatial patterns of genetic diversity in a Neotropical savanna tree species

“…Both D. mollis and D. alata are pollinated by insects and have their seeds dispersed by mammals, in spite of differences in genetic diversity and distribution during the LGM. Still, the genetic diversity and genetic differentiation found for D. mollis was lower than for two other widely distributed non-legume tree species from central Brazil, Caryocar brasiliense (Collevatti et al, 2001) and Tabebuia aurea (Collevatti et al, 2014). In fact, there is evidence of 'range retraction' with multiple refugia during the LGM for C. brasiliense and a wide historical refugium across central Brazil for both C. brasiliense and T. aurea (Collevatti et al, , 2014, similar to what we found for D. mollis.…”

“…Still, the genetic diversity and genetic differentiation found for D. mollis was lower than for two other widely distributed non-legume tree species from central Brazil, Caryocar brasiliense (Collevatti et al, 2001) and Tabebuia aurea (Collevatti et al, 2014). In fact, there is evidence of 'range retraction' with multiple refugia during the LGM for C. brasiliense and a wide historical refugium across central Brazil for both C. brasiliense and T. aurea (Collevatti et al, , 2014, similar to what we found for D. mollis. These differences in demographic history and phylogeographical patterns between savanna tree species highlight the complexity of the biogeographical processes in the Cerrado biome.…”

Effects of past climate onPassiflora actinia(Passifloraceae) populations and insights into future species management in the Brazilian Atlantic forest

“…Hijmans & Graham, ; Pliscoff et al ., ). Coupling population genetics assessment and niche modelling is a valuable strategy to investigate the influence of climate changes on intraspecific genetic diversity (Diniz‐Filho et al ., ; Collevatti et al ., ; Diniz‐Filho, Soares & Telles, ). Intraspecific variation is widely considered to have great conservation relevance, as intraspecific variation affects the evolutionary potential of this species.…”

“…Recently, species distribution modelling techniques projected to past, present and future climatic conditions have been used to understand current geographical and genetic diversity distribution of different species. By linking the patterns of geographical and genetic diversity distribution, it is possible to identify areas of climate stability and predict the impacts of climate changes on species genetic diversity (Thuiller et al ., ; Collevatti, Nabout & Diniz‐Filho, ; Espíndola et al ., ; Collevatti et al ., ).…”

Climatic changes can drive the loss of genetic diversity in a Neotropical savanna tree species

“…For instance, European oaks show fast migration, adaptation and extensive gene flow during the Quaternary that allowed them to survive and track suitable habitats in the past (see (Alberto et al., for a review). In Neotropics, the pollen fossil records have also shown modifications in vegetation community, with restoration of plant populations after the last glacial maximum, such as those associated with swamps (e.g., Behling & Hooghiemstra, ; Salgado‐Labouriau et al., ), which may indicate that Neotropical species also tracked suitable habitats or even survived in refuges (e.g., Collevatti et al., ; Collevatti, Lima‐Ribeiro, et al., ; Collevatti, Terribile, Rabelo, & Lima‐Ribeiro, ; Lima, Lima‐Ribeiro, Tinoco, Terribile, & Collevatti, ).…”