RT Journal Article
T1 Living on the edge: timing of Rand Flora disjunctions congruent with ongoing aridification in Africa
A1 Pokorny, Lisa
A1 Riina, Ricarda
A1 Mairal, Mario
A1 Meseguer, Andrea S.
A1 Culshaw, Victoria
A1 Cendoya, Jon
A1 Serrano Pérez, Luis Miguel
A1 Carbajal Vilaverde, Rodrigo
A1 Ortiz Núñez, Santiago
A1 Heuertz, Myriam
A1 Sanmartín, Isabel
K1 Africa
K1 Historical biogeography
K1 Climate change
K1 Diversification rates
K1 Long-distance dispersal
K1 Rand Flora
K1 Vicariance
AB The Rand Flora is a well-known floristic pattern in which unrelated plant lineagesshow similar disjunct distributions in the continental margins of Africa and adjacentislands—Macaronesia-northwest Africa, Horn of Africa-Southern Arabia, Eastern Africa,and Southern Africa. These lineages are now separated by environmental barriers suchas the arid regions of the Sahara and Kalahari Deserts or the tropical lowlands of CentralAfrica. Alternative explanations for the Rand Flora pattern range from vicariance andclimate-driven extinction of a widespread pan-African flora to independent dispersalevents and speciation in situ. To provide a temporal framework for this pattern, we usedpublished data from nuclear and chloroplast DNA to estimate the age of disjunction of17 lineages that span 12 families and nine orders of angiosperms. We further used theseestimates to infer diversification rates for Rand Flora disjunct clades in relation to theirhigher-level encompassing lineages. Our results indicate that most disjunctions fall withinthe Miocene and Pliocene periods, coinciding with the onset of a major aridification trend,still ongoing, in Africa. Age of disjunctions seemed to be related to the climatic affinities ofeach Rand Flora lineage, with sub-humid taxa dated earlier (e.g., Sideroxylon) and thosewith more xeric affinities (e.g., Campylanthus) diverging later. We did not find supportfor significant decreases in diversification rates in most groups, with the exception ofolder subtropical lineages (e.g., Sideroxylon, Hypericum, or Canarina), but some lineages(e.g., Cicer, Campylanthus) showed a long temporal gap between stem and crownages, suggestive of extinction. In all, the Rand Flora pattern seems to fit the definition ofbiogeographic pseudocongruence, with the pattern arising at different times in responseto the increasing aridity of the African continent, with interspersed periods of humidityallowing range expansions.
PB Frontiers Media
SN 1664-8021
YR 2015
FD 2015
LK http://hdl.handle.net/10347/22226
UL http://hdl.handle.net/10347/22226
LA eng
NO Pokorny, L., Riina, R., Mairal, M., Meseguer, A. S., Culshaw, V., Cendoya, J., ... & Sanmartín, I. (2015). Living on the edge: timing of Rand Flora disjunctions congruent with ongoing aridification in Africa. Frontiers in Genetics, 6, 154.
NO This study was funded by the Spanish Ministry of Economy and Competitiveness (MINECO): Project AFFLORA, CGL2012-40129-C02-01 to IS. LP was funded by CSIC postdoctoral contract within AFFLORA. MH was funded by CGL2012-40129-C02-02, the Research Council of Norway (203822/E40) and a Ramón y Cajal Fellowship (RYC2009-04537). RR was supported by a JAE-DOC postdoctoral fellowship (MINECO) and the European Social Fund. MM and VC were supported by MINECO FPI predoctoral fellowships (BES2010-037261 and BES-2013-065389 respectively)
DS Minerva
RD 3 may 2026