DARWIN commi ed wo chap e s o The O igin o
he Species (1872) o explain he pas and p esen dis-
ibu ion o he species. He s a ed ha pa e ns o
species dis ibu ion may o en be seen as clea oo -
s eps o hei e olu ion and di e si ica ion. Thus,
p esen -day axa dis ibu ion may be equen ly
explained by a combina ion o his o ical e en s (cli-
ma ic oscilla ions like a idi ica ions o glacia ions;
geological mo emen s like pla e ec onics o o oge-
nies) and e olu iona y p ocesses (ex inc ion, ica i-
ance, dispe sal...).
One o he mos ascina ing dis ibu ion pa e ns is
ange disjunc ion. The la ges and mos challenging
disjunc ion o biologis s, he bipola dis ibu ion,
al eady cap i a ed HUMBOLDT (1817) and DARWIN
(1859) who ealized he exis ence o common plan
species in he lo a o emo ely dis an a eas (Tie a
del Fuego in he sou he n hemisphe e and No he n
Eu ope/No h Ame ica in he no he n). DARWIN
(1872) ied o explain his disjunc ion as a o ced
mig a ion o species due o clima e change. Du ing
glacial pe iods, he ad ance o he ice-shee in he
no he n hemisphe e migh ha e pushed a c ic
species owa ds lowe la i udes; hen, a emig a ion
would ha e occu ed on he e u ning wa m h, since
hose lowland a eas a e oo wa m o hei exis ence.
Some species migh ha e ound a e ugium in moun-
ain summi s in sou he n la i udes in s ead o mo -
ing no hwa d. DARWIN (1859) hen hough ha
he e we e ew species iden ically he same in bo h
hemisphe es and on he moun ains o in e media e
opical egions, whose mu ual ela ions will no
ha e been much dis u bed. Admi ably, he s a ed all
hese hypo heses wi hou e en knowing he exis ence
o he gene ic ma e ial.
Phylogeog aphy is a ising discipline ha ies o
unde s and he easons o he dis ibu ion o species
and closely ela ed gene ic lineages, o e ime and he
e olu iona y p ocesses in ol ed (AVISE e al., 1987;
AVISE, 2000). This discipline eme ged in a mul idis-
ciplina y con ex and i in eg a es me hods and con-
cep s om popula ion gene ics (mic oe olu ion) and
om sys ema ics (mac oe olu ion).
Bipola biogeog aphy is s ill he ocus o nume ous
s udies a e Da win’s i s app oach based on o gan-
ism mig a ions (DURIETZ, 1940; WILSON, 1986;
MOORE, CHATER, 1971; MOORE, 1972; SMITH,
1986; BALL, 1990). Resea che s ha e p oposed di -
e en hypo heses o un a el he e olu iona y his o y
o bipola axa based on molecula and mo phologi-
cal da a (ESCUDERO e al., 2010; POPP e al., 2011).
The objec i e o his wo k is o b ie ly e iew he
hypo heses sugges ed o explain bipola disjunc ions
and how o es hem wi h molecula echniques.
BIPOLAR DISTRIBUTIONS IN CAREX
MOORE, CHATER (1971) e med bipola species ol-
lowing a single and simple c i e ion: such species
mus each la i udes as high as he Eu opean A c ic
o Alaska (c. 55º N. la .) in he no he n hemisphe e
and he S aigh o Magellan (c. 52º S. la .) in he
sou he n hemisphe e, ega dless o hei occu ences
elsewhe e. Unde his c i e ion, hey poin ed 30
species belonging o 12 amilies (Tab. 1) and 23 gen-
e a, 6 o hem (20%) co esponding o he genus
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Ex eme phylogeog aphy in Ca ex (Cype aceae)
T. VILLAVERDE, S. MARTÍN-BRAVO, M. ESCUDERO and M. LUCEÑO
RIASSUNTO - Filogeog a ia di es emi à di a eale in Ca ex (Cype aceae)- Le disgiunzioni negli a eali di dis ibuzione dei
axa hanno susci a o l’in e esse dei na u alis i sin dall’inizio del XIX secolo. Sono no e solo en a specie a en i dis ibu-
zione bipola e e Ca ex isul a il gene e con il maggio nume o di specie bipola i. Una disciplina eme gen e, la ilogeog a-
ia, do ebbe esse e usa a pe es a e le ipo esi sulle specie bipola i poiché en a di spiega e le cause e i p ocessi di e olu-
zione ela i i alla dis ibuzione delle specie e alle lo o elazioni gene iche. Sono p opos e di e se ipo esi pe spiega e le dis-
giunzioni bipola i: ica ianza, pa allelismo, con e genza, dispe sione a lunga dis anza e spos amen o a balzi sui ilie i.
Key wo ds: bipola disjunc ions, Ca ex, long dis ance dispe sal, moun ain hopping, pa allelism, phylogeog aphy, ica iance
INTRODUCTION
A i Riunione Scien i ica Sezione Piemon e - Valle d’Aos a
Ca ex L. (Cype aceae). Al hough Poaceae amily has 8
bipola species, hey a e belonging o h ee di e en
gene a (Phleum, Poa and Deschampsia). Then, Ca ex
is he genus wi h mo e bipola species. Why such a
s iking pa e n is so commonly ound wi hin Ca ex?
This is no only he la ges genus wi hin he
Cype aceae amily, wi h mo e han 2.000 species
(KÜKENTHAL, 1909) dis ibu ed ac oss all lo is ic
egions (REZNICEK, 1990), bu also he mos di e se
angiospe m genus o he no he n empe a e zone
(ESCUDERO e al., 2012). I con ains many cold-
adap ed species ha a e eligible o ha e eached
ex eme la i udes in bo h hemisphe es and, he e o e,
he bipola dis ibu ion. Amphi opical species o
lowe la i udes migh no be conside ed as bipola
because hei en i onmen al and biological his o ies
a e likely o sepa a e hem om he a c ic-alpine
lo a when in es iga ing he ac o s in ol ed in he
pa e ns o hei dis ibu ions (RAVEN, 1963).
Ca ex is di ided in ou sub-gene a based on mo pho-
logical and molecula da a (STARR, FORD, 2009).
Th ee o hem ha e a leas one bipola species: C.
a c ogena H.Sm. and C. mic oglochin Wahlenb. in
subgenus Psyllopho a (Degl.) Pe e m.; C. canescens L.,
C. maclo iana D’U . and C. ma i ima Gunn. in sub-
genus Vignea (P. Beau . ex Les ib. .) Pe e m.; C. mag-
ellanica Lam. in subgenus Ca ex L. All hese species
a e p esen in Tie a del Fuego (Pa agonia, A gen ina)
and in a c ic-alpine a eas o Eu asia and No h
Ame ica. Ca ex canescens is also p esen in Aus alia. A
de ailed axonomic s udy o each bipola species
encompassing popula ions ac oss i s ange should be
manda o y be o e u he s eps owa ds elucida ing
he o igin o such disjunc ions. Fo example, some
popula ions o C. mic oglochin in Sou h Ame ica we e
ound o belong o a di e en species, C. camp-
oglochin (WHEELER, GUAGLIANONE, 2003).
HYPOTHESES TO TEST
Once he axonomy o he bipola species has been
clea ly sol ed, i is possible o s udy hei biogeog a-
phy and e olu iona y ela ionships. The geog aphi-
cal sepa a ion ound in bipola species migh be con-
side ed as a majo ac o dis up ing he pa e n o
gene low. I gene ic isola ion allows no he n and
sou he n popula ions o di e ge sepa a ely, i may
lead o he accumula ion o molecula and mo pho-
logical di e ences o clea ly dis inguish hem.
Di e en deg ees o di e en ia ion may accoun o
di e en hypo heses.
VICARIANCE, PARALLELISM AND CONVERGENCE
Molecula di e ences be ween No he n and
Sou he n Hemisphe e popula ions migh be due o
hei dissimila e olu ion. Popula ions migh ha e
es ed gene ically isola ed o agmen ed, allowing a
dis inc molecula di e gence bu no a mo phologi-
cal one.
To ejec ica iance hypo hesis, es ima ion o di e -
gence imes may help o es he cong uence be ween
phylogene ic spli s and ecological equi emen s. The
ela i e age o his disjunc ion was e alua ed h ough
es ima ion o di e gence imes and ossil e idences.
Pa allelism o con e gence hypo heses imply he
accumula ion o e olu iona y s eps in he same ash-
ion in no he n and sou he n popula ions o dis an -
ly ela ed lineages, in his case popula ions would
belong o polyphyle ic g oups. The e o e, o ejec
hese hypo heses, ex eme edges popula ions mus be
shown as oge he monophyle ic.
DIRECT LONG DISTANCE DISPERSAL
I he e a e no obse ed molecula di e ences
be ween popula ions, i migh be possible o consid-
e a long dis ance dispe sal hypo hesis, occu ed in
ecen imes. To ejec his hypo hesis, popula ions a
he ex emes o he dis ibu ion mus belong o
ancien monophyle ic di e gen g oups.
ESCUDERO e al. (2010) sampled i e o he six bipo-
la Ca ex species (C. a c ogena was no included) o
a molecula app oach and sugges ed long-dis an dis-
pe sal, sensu la o, as he mos plausible cause o bipo-
la disjunc ion o C. canescens, C. maclo iana, C.
magellanica and C. ma i ima. Al hough al e na i e
dispe sal hypo heses (e.g. di ec long-dis an dispe -
sal) could no be es ed due o hei sampling
m hod, genealogical ela ionships o chlo oplas
haplo ypes indica ed a sou hwa ds di ec ion o dis-
pe sal o C. canescens, C. maclo iana and C. magel-
lanica (ESCUDERO e al., 2010).
MOUNTAIN HOPPING
The moun ain-hopping hypo hesis (BALL, 1990)
elies on he idea ha species ha e p og essi ely
mig a ed om one moun ain chain o he nex (as
s epping-s ones) h ough he low la i ude egions o
achie e such dis ibu ion (MOORE, CHATER, 1971;
VOLLAN e al., 2006). Unde his hypo hesis, i a
59A i Riunione Scien i ica Sezione Piemon e - Valle d’Aos a
TABLE 1
Numbe o bipola species in ascula plan s amilies
(MOORE, CHATER, 1971).
Nume o delle specie bipola i nell’ambi o delle amiglie di
pian e ascola i (MOORE, CHATER, 1971).
Family Numbe
Lycopodiaceae P. Beau . ex Mi b. 1
Plumbaginaceae Juss. 1
Gen ianaceae Juss. 1
Sc ophula iaceae Juss. 1
Juncaginaceae Rich. 1
Hymenophyllaceae Ma . 2
Polygonaceae Juss. 2
Ranunculaceae Juss. 2
Plan aginaceae Juss. 2
Ca yophyllaceae Juss. 3
Cype aceae Juss. 6
Poaceae Ba nha 8
b oad sampling o he dis ibu ion a eas is ob ained,
nea by popula ions should ha e highe molecula
a ini y han he popula ions a he ex eme o he
dis ibu ion. To ejec his hypo hesis, molecula dis-
simila i ies mus no clea ly dis inguish no he n and
sou he n popula ions.
MEANS OF DISPERSAL
Al hough some mechanisms and synd omes o dis-
pe sal ha e been desc ibed wi hin he genus Ca ex
(ALLESSIO LECK, SCHÜTZ, 2005) i gene ally lacks o
any means o long-dis ance dispe sal (STEENIS VAN,
1962; RAVEN, 1963). Only wo bipola species, C.
maclo iana and C. mic oglochin, display some ea-
u es o dispe sal (winged and hooked u icules,
espec i ely, MASTROGIUSEPPE e al., 2002; SAVILE,
1972). Howe e , he e is no enough e idence o
explain such wide dissemina ion simply by mo pho-
logical dispe sal peculia i ies (ESCUDERO e al.,
2010).
DARWIN (1859) sugges ed ha some plan s migh
also be in luenced by occasional ec o s o dis ibu-
ion such as sea wa e (su i al in sea wa e o days
in spi e o no being adap ed o his mean o dispe -
sal) o bi ds (adhe ing o oo o kep in bi d giz-
za ds). RAVEN (1963) also poin ed o bi ds as impo -
an ec o s in plan dispe sal, sugges ing ha many
o he disjunc ions, such as bipola o amphi-
A lan ic, co espond wi h bi d mig a ion ou es. An
example o a ecen long dis an dispe sal a ou ed
by bi ds was p oposed in Emp e um (POPP e al.,
2011).
CONCLUSIONS
The ac ha bipola species’ axonomy is o en un e-
sol ed (e.g. A me ia ma i ima Willd., BAUMBACH,
HELWIG, 2007; Osmo hiza be e oi DC., WEN e al.,
2002) could be a p oblem when in e p e ing molec-
ula esul s. Besides, he exac numbe o bipola
species migh luc ua e when hey a e he subjec o
axonomic e isions (MOORE, CHATER, 1971).
While es ing hypo heses o bipola disjunc ions in
clea biological en i ies, nuclea and chlo oplas
DNA a e ecommended o be explo ed. Nuclea
DNA (e.g. ITS egion, nuclea low copy genes, o
AFLPs pheno ypes) is commonly used in biogeo-
g aphical s udies and gi es enough e idence o eluci-
da e whe he he e is gene low be ween popula ions.
On he o he hand, chlo oplas DNA (e.g. ma k,
ps16, nL) is sui able o econs uc phylogeog aph-
ical pa e ns and ollow plan dispe sion di ec ions,
by pe o ming analyses such as haplo ype ne wo k
es ima ions.
Once he axonomy o a species g oup is sol ed and
accu a e phylogenies a e made, es ima ion o lineage
di e gence imes could be in e ed.
Al hough ossil e idence in Ca ex is sca ce (SMITH e
al., 2009), a emp s o da e specia ion e en s such as
ha conduc ed by DRAGON, BARRINGTON (2009)
could acili a e he unde s anding o e olu iona y
p ocesses in he genus.
Acknowledgemen s -.The au ho s would like o hank he
Socie à Bo anica I aliana o he in i a ion o p esen his
communica ion a he Symposium on Cype aceae 2012,
and especially E. Ma ine o and A. Pis a ino o he sup-
po gi en a he mee ing.
LITERATURE
ALLESSIO LECK M., SCHÜTZ W., 2005 – Regene a ion o
Cype aceae, whi pa icula e e ence o seed ecology and
seed banks. Pe spec . Plan Ecol. E ol. Sys . 7: 95-133.
AVISE J.C., 2000 – Phylogeog aphy: he his o y and o ma-
ion o species. Ha a d Uni e si y P ess, Camb idge,
Massachuse s, USA.
AVISE J.C., ARNOLD J., BALL R.M. JR, BERMINGHAM E.,
LAMB T., NEIGEL J.E., REEB C.A., SAUNDERS N.C.,
1987 – In aspeci ic phylogeog aphy: he mi ochond ial
DNA b idge be ween popula ion gene ics and sys ema ics.
Ann. Re . Ecol. Sys ., 18: 489-522.
BALL P.W., 1990 – Some aspec s o he phy ogeog aphy o
Ca ex.Can. J. Bo ., 68: 1462-1472.
BAUMBACH H., HELLWIG F.H., 2007 – Gene ic di e en ia-
ion o me allicolous and non-me allicolous A me ia
ma i ima (Mill.) Willd. axa (Plumbaginaceae) in cen-
al Eu ope. Plan Sys . E ol., 269: 245-258.
DARWIN C., 1859 – On he O igin o he Species by Means
o Na u al Selec ion, o he Pe se a ion i Fa ou ed
Ra es in he S uggle o Li e. Mu ay, London.
—, 1872 – The O igin o he Species. Mu ay, London, 6 h ed.
DRAGON J.A., BARRINGTON D.S., 2009 – Sys ema ics o
he Ca ex aqua ilis and Ca ex len icula is lineages:
Geog aphically and ecologically di e gen sis e clades o
Ca ex sec ion Phacocys is (Cype aceae). Am. J. Bo .,
96: 1896-1906.
DURIETZ G.E., 1940 – P oblems o he bipola plan dis i-
bu ion. Ac a Phy ogeog aphica Suecica, 13: 215-282.
ESCUDERO M., HIPP A.L., WATERWAY M.J., VALENTE
L.M., 2012 – Di e si ica ion a es and ch omosome e o-
lu ion in he mos di e se angiospe m genus o he empe -
a e zone (Ca ex, Cype aceae). Mol., Phyl. E ol., 63(3),
650-655.
ESCUDERO M., VARCÁRCEL V., VARGAS P., LUCEÑO M.,
2010 – Bipola disjunc ions in Ca ex: long-dis an dispe -
al, ica iance o pa allel e olu ion?. Flo a, 205: 118-127.
HUMBOLDT F.W.H., 1817 – De dis ibu ione geog aphica
pla a um secundum coeli empe iem e al i udem mon-
ium, P olegomena. Lib a ia g aeco-la ino-ge manica,
Pa is.
KÜKENTHAL G., 1909 – Cype aceae-Ca icoideae. In:
ENGLER A. (Ed.), Das P lanzen eich, IV(20): 1-814.
Engelmann, Leipzig.
MASTROGIUSEPPE J., ROTHROCK P.E., DIBBLE A.C.,
REZNICEK A.A., 2002 – Ca ex L. sec . O ales Kun h.
In: FLORA OF NORTH AMERICA EDITORIAL
COMMITTEE (Ed.), Flo a o No h Ame ica No h o
Mexico, ol. 23: 332-378. Ox o d Uni e si y P ess,
New Yo k.
MOORE D.M., 1972 – Connec ions be ween cool empe a e
lo as, wi h pa icula e ence o sou he n Sou h
Ame ica. In: VALENTINE D.H. (Ed.), Taxonomy,
Phy ogeog aphy and E olu ion: 115-138. Academic
P ess, London.
MOORE D.M., CHATER A.O., 1971 – S udies on bipola
species I. Bo . No ., 124: 317-334.
POPP M., MIRRÉ V., BROCHMAN C., 2011 – A single mid-
Pleis ocene long-dis ance dispe sal by a b id can explain
he ex eme bipola disjunc ion in c owbe is
(Empe um). P oc. Na . Acad. Sci., 108: 6520-6525.
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RAVEN P.H., 1963 – Amphi opical ela ionships in he lo-
as o No h and Sou h Ame ica. Qua . Re . Biol., 38:
151-177.
REZNICEK A.A., 1990 – E olu ion in sedges (Ca ex,
Cype aceae). Can. J. Bo ., 68: 1409-1432.
SAVILE D.B.O., 1972 – A c ic adap a ions in plan s.
Monog aph 6, Resea ch B anch, Canada Depa men
o Ag icul u e, O awa.
SMITH J.M.B., 1986 – O igins o he Aus alasian opi-
calpine and alpine lo as. In: BARLOW B.A. (Ed.), Flo a
and Fauna o Alpine Aus alia: 109-128. CSIRO,
Melbou ne.
SMITH S.Y., COLLINSON M.E., SIMPSON D.A., RUDALL
P.J., STAMPANONI F.M., 2009 – Elucida ing he a ini-
ies and habi a o ancien , widesp ead Cype aceae:
Volke ia messelensis gen. e sp. no ., a ossil mapanoid
sedge om he Eocene o Eu ope. Am. J. Bo ., 96: 1506-
1518.
STARR J.R., FORD B.A., 2009 – Phylogeny and e olu ion in
Ca iceae (Cype aceae): cu en knowledge and u u e
di ec ions. Bo . Re ., 75: 110-137.
STEENIS C.G. VAN, 1962 – The moun ain lo a o he
Malaysian opics. Endea ou , 21: 183-193.
VOLLAN K., HEIDE O., HEUN M., 2006 – Gene ic a ia-
ion, axonomy and moun ain-hopping o ou bipola
Ca ex species (Cype aceae) analysed by AFLP inge -
p in ing. Aus alian J. Bo ., 54: 304-313.
WEN J., PORTER P.P., LOWRY I.I., WALCK J.L., YOO K.,
2002 – Phylogene ic biogeog aphic di e si ica ion in
Osmo hiza (Apiaceae). Ann. Missou i Bo . Ga den,
89: 414-428.
WHEELER G.A., GUAGLIANONE E.R., 2003 – No es on
Sou h Ame ican Ca ex (Cype aceae): C. camp oglo-
chin and C. mic oglochin. Da winiana, 41: 193-206.
WILSON J.B., 1986 – Alpine species o Cype aceae and
Juncaceae.In: BARLOW B.A. (Ed.), Flo a and Fauna o
Alpine Aus alia: 472-488. CSIRO, Melbou ne.
ABSTRACT - G ea dis ibu ion disjunc ions o axa
ha e cap i a ed na u alis s since he beginning o he
XX h cen u y. Only hi y species a e known o ha e a
bipola dis ibu ion, being Ca ex he genus wi h he
la ges numbe o bipola species. A ising discipline, phy-
logeog aphy, could be used o es o hypo heses in bipo-
la species since i ies o unde s and he easons and he
e olu iona y p ocesses in ol ed o he dis ibu ion o
species and hei closely ela ed gene ic lineages. Di e en
hypo heses a e sugges ed o bipola disjunc ions: ica i-
ance, pa allelism, con e gence, long dis an dispe sal and
moun ain hopping.
61A i Riunione Scien i ica Sezione Piemon e - Valle d’Aos a
AUTHORS
Tama a Villa e de ( [email protected]), San iago Ma ín-B a o, Ma cial Escude o, Modes o Luceño, Á ea de Bo ánica,
Depa amen o de Biología Molecula e Ingenie ía Bioquímica, Uni e sidad Pablo de Ola ide, C . de U e a s/n, 41008 Se illa,
Spain