Volcanism rather than climatic oscillations explains the shared phylogeographic patterns among ecologically distinct plant species in the southernmost areas of the South American Arid Diagonal

CRISTIAN, BARANZELLI MATIAS; ANDRÉS, ISSALY EDUARDO; GUADALUPE, ANDRACA-GÓMEZ; NOEMÍ, SÉRSIC ALICIA; ANDREA, COSACOV; LUCÍA, AGUILAR DANA; ALEJANDRO, PETRINOVIC IVÁN; NICOLÁS, ROCAMUNDI; ANDRÉS, CAMPS GONZALO; JOHNSON LEIGH, A.

PERSPECTIVES IN PLANT ECOLOGY EVOLUTION AND SYSTEMATICS

ELSEVIER GMBH

Año: 2020

1433-8319

Sharedgeneticpatternswithinacommunityofecologicallydistinctspeciesmayreflecttheroleofpastgeoclimatic events imprinting species evolutionary history. Although Pleistocene glaciations are the most important processes evoked as drivers of these shared patterns, in some regions Quaternary volcanic activity should also be considered as a potential process shaping genetic diversity distribution. Additionally, phenotypic attributes related to dispersal and persistence may affect the time and manner in which species respond to geoclimatic changes. We performed a comparative phylogeographical study within a plant community of the South American Arid Diagonal to assess whether genetic patterns are better explained by climatic changes or volcanisms, takingintoaccountthepossibleinfluenceoflifeformanddispersalsyndromesofthefocalspecies.Chloroplast intergenicspacersweresequencedforfiveplantspecies.Genealogy,divergencetimeestimates,demographicand rangeexpansionanalyseswereperformed.ApproximateBayesiancomputationwasusedtotestplausibleshared phylogeographicscenarios.Climaticallystableareasduringthelastglacialperiodwereinferredwithdistribution modeling.Resultsshowedthatmostspeciesweresplitintonorthernandsouthernlineagesseparatedbyaphylogeographicbreakataround37.5°S,withthenorthernpopulationsbeinggeneticallylessdiverse,inhabitingboth climaticallystableandunstableareas,butbeingseverelyaffectedbyintensePlio-Pleistocenemagmaticactivity; the southern populations, less influenced by volcanism, appeared to be genetically more diverse and occupied climaticallystableareasthroughtime.Mostrecentrangeexpansionsandeffectivepopulationsizeincreasesoccurredaftermostofthevolcanicepisodes,beforeandduringtheLastGlacialMaximum.Allspeciessharedthe same geographic origin of the detected spatial expansion. Overall, our results suggest a preponderant effect of Quaternaryvolcanismratherthanclimaticoscillationsontheevolutionaryhistoryofthisxerophyticcommunity. Additionally, we found evidence that autecological traits would have modulated the community historical responses.