LIVING ON THE EDGE: TIMING OF RAND FLORA DISJUNCTIONS CONGRUENT WITH ONGOING ARIDIFICATION IN AFRICA
The Rand Flora is a well-known floristic pattern in which unrelated plant lineages show similar disjunct distributions in the continental margins of Africa and adjacent islands —Macaronesia-northwest Africa, Horn of Africa-Southern Arabia, Eastern Africa, and Southern Africa. These lineages are now...
| Main Authors: | , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2015-05-01
|
| Series: | Frontiers in Genetics |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fgene.2015.00154/full |
| _version_ | 1818940325291360256 |
|---|---|
| author | Lisa ePokorny Ricarda eRiina Mario eMairal Andrea S. Meseguer Victoria eCulshaw Jon eCendoya Miguel eSerrano Rodrigo eCarbajal Santiago eOrtiz Myriam eHeuertz Myriam eHeuertz Myriam eHeuertz Isabel eSanmartin |
| author_facet | Lisa ePokorny Ricarda eRiina Mario eMairal Andrea S. Meseguer Victoria eCulshaw Jon eCendoya Miguel eSerrano Rodrigo eCarbajal Santiago eOrtiz Myriam eHeuertz Myriam eHeuertz Myriam eHeuertz Isabel eSanmartin |
| author_sort | Lisa ePokorny |
| collection | DOAJ |
| description | The Rand Flora is a well-known floristic pattern in which unrelated plant lineages show similar disjunct distributions in the continental margins of Africa and adjacent islands —Macaronesia-northwest Africa, Horn of Africa-Southern Arabia, Eastern Africa, and Southern Africa. These lineages are now separated by environmental barriers such as the arid regions of the Sahara and Kalahari Deserts or the tropical lowlands of Central Africa. Alternative explanations for the Rand Flora pattern range from vicariance and climate-driven extinction of a widespread pan-African flora to independent dispersal events and speciation in situ. To provide a temporal framework for this pattern, we used published data from nuclear and chloroplast DNA to estimate the age of disjunction of 17 lineages that span 12 families and 9 orders of angiosperms. We further used these estimates to infer diversification rates for Rand Flora disjunct clades in relation to their higher-level encompassing lineages. Our results indicate that most disjunctions fall within the 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 of each Rand Flora lineage, with subtropical taxa dated earlier (e.g., Sideroxylon) and those with more xeric affinities (e.g., Campylanthus) diverging later. We did not find support for significant decreases in diversification rates in most groups, with the exception of older subtropical lineages (e.g., Sideroxylon, Hypericum, or Canarina), but some lineages (e.g., Cicer, Campylanthus) showed a long temporal gap between stem and crown ages, suggestive of extinction. In all, the Rand Flora pattern seems to fit the definition of biogeographic pseudocongruence, with the pattern arising at different times in response to the increasing aridity of the African continent, with interspersed periods of humidity allowing range expansions. |
| first_indexed | 2024-12-20T06:37:51Z |
| format | Article |
| id | doaj.art-4d4a23f4315b44b4a69410a89709b111 |
| institution | Directory Open Access Journal |
| issn | 1664-8021 |
| language | English |
| last_indexed | 2024-12-20T06:37:51Z |
| publishDate | 2015-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Genetics |
| spelling | doaj.art-4d4a23f4315b44b4a69410a89709b1112022-12-21T19:49:56ZengFrontiers Media S.A.Frontiers in Genetics1664-80212015-05-01610.3389/fgene.2015.00154121703LIVING ON THE EDGE: TIMING OF RAND FLORA DISJUNCTIONS CONGRUENT WITH ONGOING ARIDIFICATION IN AFRICALisa ePokorny0Ricarda eRiina1Mario eMairal2Andrea S. Meseguer3Victoria eCulshaw4Jon eCendoya5Miguel eSerrano6Rodrigo eCarbajal7Santiago eOrtiz8Myriam eHeuertz9Myriam eHeuertz10Myriam eHeuertz11Isabel eSanmartin12Real Jardín Botánico (RJB-CSIC)Real Jardín Botánico (RJB-CSIC)Real Jardín Botánico (RJB-CSIC)INRA, UMR 1062, Centre de Biologie pour la Gestion des Populations CBGP (INRA, IRD, CIRAD, Montpellier SupAgro)Real Jardín Botánico (RJB-CSIC)Real Jardín Botánico (RJB-CSIC)University of Santiago de CompostelaUniversity of Santiago de CompostelaUniversity of Santiago de CompostelaForest Research Centre (CIFOR-INIA)INRA, BIOGECO, UMR 1202University of Bordeaux, BIOGECO, UMR 1202Real Jardín Botánico (RJB-CSIC)The Rand Flora is a well-known floristic pattern in which unrelated plant lineages show similar disjunct distributions in the continental margins of Africa and adjacent islands —Macaronesia-northwest Africa, Horn of Africa-Southern Arabia, Eastern Africa, and Southern Africa. These lineages are now separated by environmental barriers such as the arid regions of the Sahara and Kalahari Deserts or the tropical lowlands of Central Africa. Alternative explanations for the Rand Flora pattern range from vicariance and climate-driven extinction of a widespread pan-African flora to independent dispersal events and speciation in situ. To provide a temporal framework for this pattern, we used published data from nuclear and chloroplast DNA to estimate the age of disjunction of 17 lineages that span 12 families and 9 orders of angiosperms. We further used these estimates to infer diversification rates for Rand Flora disjunct clades in relation to their higher-level encompassing lineages. Our results indicate that most disjunctions fall within the 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 of each Rand Flora lineage, with subtropical taxa dated earlier (e.g., Sideroxylon) and those with more xeric affinities (e.g., Campylanthus) diverging later. We did not find support for significant decreases in diversification rates in most groups, with the exception of older subtropical lineages (e.g., Sideroxylon, Hypericum, or Canarina), but some lineages (e.g., Cicer, Campylanthus) showed a long temporal gap between stem and crown ages, suggestive of extinction. In all, the Rand Flora pattern seems to fit the definition of biogeographic pseudocongruence, with the pattern arising at different times in response to the increasing aridity of the African continent, with interspersed periods of humidity allowing range expansions.http://journal.frontiersin.org/Journal/10.3389/fgene.2015.00154/fullAfricaClimate Changehistorical biogeographydiversification ratesvicariancelong-distance dispersal |
| spellingShingle | Lisa ePokorny Ricarda eRiina Mario eMairal Andrea S. Meseguer Victoria eCulshaw Jon eCendoya Miguel eSerrano Rodrigo eCarbajal Santiago eOrtiz Myriam eHeuertz Myriam eHeuertz Myriam eHeuertz Isabel eSanmartin LIVING ON THE EDGE: TIMING OF RAND FLORA DISJUNCTIONS CONGRUENT WITH ONGOING ARIDIFICATION IN AFRICA Frontiers in Genetics Africa Climate Change historical biogeography diversification rates vicariance long-distance dispersal |
| title | LIVING ON THE EDGE: TIMING OF RAND FLORA DISJUNCTIONS CONGRUENT WITH ONGOING ARIDIFICATION IN AFRICA |
| title_full | LIVING ON THE EDGE: TIMING OF RAND FLORA DISJUNCTIONS CONGRUENT WITH ONGOING ARIDIFICATION IN AFRICA |
| title_fullStr | LIVING ON THE EDGE: TIMING OF RAND FLORA DISJUNCTIONS CONGRUENT WITH ONGOING ARIDIFICATION IN AFRICA |
| title_full_unstemmed | LIVING ON THE EDGE: TIMING OF RAND FLORA DISJUNCTIONS CONGRUENT WITH ONGOING ARIDIFICATION IN AFRICA |
| title_short | LIVING ON THE EDGE: TIMING OF RAND FLORA DISJUNCTIONS CONGRUENT WITH ONGOING ARIDIFICATION IN AFRICA |
| title_sort | living on the edge timing of rand flora disjunctions congruent with ongoing aridification in africa |
| topic | Africa Climate Change historical biogeography diversification rates vicariance long-distance dispersal |
| url | http://journal.frontiersin.org/Journal/10.3389/fgene.2015.00154/full |
| work_keys_str_mv | AT lisaepokorny livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT ricardaeriina livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT marioemairal livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT andreasmeseguer livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT victoriaeculshaw livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT jonecendoya livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT migueleserrano livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT rodrigoecarbajal livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT santiagoeortiz livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT myriameheuertz livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT myriameheuertz livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT myriameheuertz livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica AT isabelesanmartin livingontheedgetimingofrandfloradisjunctionscongruentwithongoingaridificationinafrica |