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DARWINIANA 50(2): 218-251. 2012Versin final, efectivamente publicadael 28 de diciembre de 2012

Original recibido el 4 de abril de 2012, aceptado el 30 de octubre de 2012

ISSN 1850-1699 (electrnica)ISSN 0011-6793 (impresa)

218

This paper analyzes the distribution of vascular plants species endemic to the southern central Andes(south-western Bolivia and north-western Argentina). All 540 species endemic to the study regions (ap-prox. 720600 km2) have been included in the analysis. The main part of the endemic species is found insemiarid habitats between 1500-3500 m asl pointing to the topographically complex plateau, slope, andvalley system of the southern central Andes as the main locations for its endemic flora. The distributionof the endemic species within arid sites is in contrast with that of vascular plant diversity in general,as the most diverse habitat of the region is the moist subtropical Tucumano-Bolivian Yungas forest ofthe eastern Andes slope. A total of 17 well defined and partly overlapping distribution patterns wereindentified. The broadest distribution pattern defines a general area of endemism for the southern centralAndes. This area extends through nearly the entire region and is defined by species that are widespread

within the region in desert to sub-humid environments of the high Andes, slopes, or valleys. Nearly allother areas of endemism are nested within this broad distribution pattern as successively north-southoverlapping areas along the slopes and valleys of the Andes and the Pampeanas Range. Despite thedistributional bias of endemism towards the arid sites almost half of the endemic species are restrictedto a few high endemic areas that lie in juxtaposition to the main rainfall zones. These areas contain thewidest habitat ranges in terms of altitude and rainfall within the region with the endemic species beingequally variable in altitude and moisture requirements. Previous defined phytogeographic units were notrecognized among the distribution patterns. However, the northern part of the Prepuna can be defined astwo partly overlapping distribution patterns.

Abstract. Aagesen, L.; M. J. Bena, S. Nomdedeu, A. Panizza, R. P. Lpez & F. O. Zuloaga. 2012. Areas of endemismin the southern central Andes.Darwiniana50(2): 218-251.

AREAS OF ENDEMISM IN THE SOUTHERN CENTRAL ANDES

1Instituto de Botnica Darwinion (ANCEFN-CONICET), Labardn 200, Casilla de Correo 22, B1642HYD San Isidro,

Buenos Aires, Argentina;[email protected] (author for correspondence).2Herbario Nacional de Bolivia, Campus Universitario, Cotacota, calle 27 s/n, Casilla 3-35121 La Paz, Boliva.3Laboratorio de Ecosiologa-IEB, Departamento de Biologa, Universidad de La Serena, Casilla de correo 599, La

Serena, Chile.

Lone Aagesen1

, Maria J. Bena1

, Soledad Nomdedeu1

, Adela Panizza1

, Ramiro P. Lpez2, 3

& Fernando O. Zuloaga1

Keywords.Areas of endemism; Argentina; biogeography; Bolivia; endemic vascular plants; southerncentral Andes.

Resumen. Aagesen, L.; M. J. Bena, S. Nomdedeu, A. Panizza, R. P. Lpez & F. O. Zuloaga. 2012. reas de endemis-mo en el sur de los Andes Centrales.Darwiniana50(2): 218-251.

Este trabajo analiza la distribucin de especies de plantas vasculares endmicas de la porcin surde los Andes centrales (sudoeste de Bolivia y noroeste de Argentina). En el anlisis se incluyeron 540especies endmicas de la regin estudiada (aproximadamente 720.600 km2). La mayora de las especiesendmicas se halla en ambientes semiridos, entre 1500-3500 m s.m., encontrndose principalmente envalles, laderas y mesetas del topogrficamente complejo sur de los Andes centrales. Las reas de ende-mismos aqu halladas se presentan consecuentemente en ambientes ridos y no en ambientes hmedossubtropicales de las Yungas tucumano-bolivianas, a pesar de que en esta ltima regin la diversidad de

plantas vasculares es mayor. Se identificaron un total de 17 patrones de distribucin bien definidos, yparcialmente solapados. El patrn de distribucin ms amplio define un rea general de endemismospara los Andes centrales. Esta rea se extiende a lo largo de casi toda la regin y est delimitada porespecies que se distribuyen en ambientes desrticos a sub-hmedos en laderas, valles o regiones altoan-dinas. Casi todas las restantes reas de endemismo se encuentran anidadas dentro del patrn de distri-bucin amplio antes citado, superponindose en el sentido norte-sur a lo largo de pendientes y valles delos Andes y de las Sierras Pampeanas. A pesar del sesgo observado en la distribucin hacia ambientes


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L. AAGESEN ET AL. Areas of endemism in the Southern Central Andes

found within the more arid vegetation on the innerslopes and valleys.

In their biogeographic analysis of South Amer-ica, Cabrera & Willink (1973) and Cabrera (1976)emphasised the distinctiveness of the slope vegeta-tion in the southern central Andes by differentiat-ing the vegetation between 2400-3500 m asl as thePrepuna phytogeographic province. The Prepunawas originally restricted to north-western Argenti-na (Cabrera, 1976), but later expanded to includethe dry inter-Andean valleys of southern Bolivia(Lpez, 2000, 2003). Since the phytogeographicunits in the traditional scheme of Cabrera are basedon the presence of endemic taxa (Cabrera, 1951,

1953; Ribichich, 2002) it is reasonable to expectthat at least part of the endemic species are distrib-uted along the Prepuna, therefore defining the lim-its of this phytogeographic unit.

Here we explore the distribution pattern of thevascular plant species endemic to the southerncentral Andes including the Prepuna province inits entire extension. Defining areas of endemismis considered fundamental for historical and eco-logical biogeography (Crisp et al., 2001), butalso for conservation studies especially if ende-

mism is found out of the high diverse vegetationtypes as protected area systems focus on diver-sity hotspots (Orme et al., 2005). Our main aimsare to explore how the endemic species are dis-tributed within the southern central Andes, iden-tify areas of endemism, and examine to whichextent these main areas of endemism correspondto pre-established phytogeographic units such asthe Prepuna slope vegetation, or found within thehigh diverse Yungas forest. We used the optimal-

ity criterion developed by Szumik et al. (2002)and Szumik & Goloboff (2004) and implementedin the program NDM/VNDM (Goloboff, 2005)to analyze the distribution of the species endemicto the north-western Argentina and south-west-ern Bolivia.

ridos, aproximadamente la mitad de las especies endmicas estn restringidas a unas pocas reas dealto endemismo, las que se encuentran en yuxtaposicin con las zonas ms lluviosas de la regin. Estasreas de alto endemismo incluyen los rangos de hbitat ms amplios de la regin en trminos de altitudy precipitacin, siendo las especies endmicas igualmente variables en sus requerimientos de humedady elevacin. Las unidades fitogeogrficas previamente definidas por diversos autores no fueron encon-tradas entre los patrones de distribucin hallados; no obstante, la parte norte de la provincia Prepuneapuede ser definida con dos patrones de distribucin parcialmente superpuestos.

INTRODUCTION

Located in the centre of the South American drydiagonal, the southern central Andes have receivedrelatively little attention in terms of quantitativephytogeographic studies. At a continental scale,hotspots and areas of endemism have mainly beendefined and explored in more humid portions ofthe Andes, such as the northern Andes or northerncentral Andes (e.g. Kier et al., 2005; Orme et al.,2005; Sklen et al., 2011) and in the southern An-des (Arroyo et al., 1999, 2004; Rodrguez-Cabralet al., 2008).

Within the southern cone of South America the

endemic vascular flora is concentrated in the welldocumented Chilean hotspot (Arroyo et al., 1999,2004; Bannister et al., 2012 and references therein).However, the arid southern central Andes appear tobe the second most important area of endemism, aschecklists and catalogues show that north-westernArgentina contains far more endemic species thanthe remaining of the region including Uruguay,southern Brazil, and southern Paraguay (Zuloaga etal., 1999, 2008).

During the Tertiary, the central Andes became

relatively dryer than the northern and southern part(Simpson & Todzia, 1990). Comparative floristicstudies along the Andes have identified the floraof the southern central Andes as a separate unitamong other arid plant formations (Lpez et al.,2006) and found more similarities at generic andfamily level between the high Andean flora of thehumid northern and southern Andes than betweenthese and the high Andean flora of the dry centralAndes (Simpson & Todzia, 1990). Summer rainfall

is sufficiently high on the eastern slopes to sup-port humid subtropical Yungas forest that is one ofthe most diverse habitats within the southern cone(Brown, 1995). However, no quantitative studieshave examined whether endemism in the south-ern central Andes is related to the Yungas forest or

Palabras clave.reas de endemismo; Argentina; biogeografa; Bolivia; plantas vasculares endmi-cas; sur de los Andes centrales.


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MATERIALS AND METHODS

Study Region

The study region comprises all west Argentinean

provinces between the Bolivian border and ~32 Sas well as the adjacent southern Bolivia depart-ments of Tarija, Chuquisaca, and Potos (see mapsin Fig. 1-2). The Chaco basin towards the east (Fig.1) and the hyper arid northern Chile to the westmake natural borders of the study region while thesouthern limit follows the northern limit of the Pa-tagonian biogeographic province (Cabrera, 1979;Cabrera & Willink, 1973; Morrone, 2001). Thenorthern limit follows Lpez (2000) and Lpez &Beck (2002), authors who analyzed the floristiccomposition of the Bolivian Prepuna and stressedthe floristic relationship between the southern Bo-livia and the north-western Argentina (see alsoIbisch et al., 2003). The study region comprises ap-prox. 720.600 km2.

Rainfall mainly occurs during the southernhemisphere summer where the South AmericanMonsoon System (SAMS) brings moist air to theregion (Zhou & Lau, 1998). The influence of theSAMS decreases by an east-west and north-south

gradient (Fig. 2A). In the southernmost part of thestudy region rainfall due to the SAMS is low whilewinter rain is higher due to the influence of the Pa-cific westerlies that brings winter rain to centralChile (Montecinos & Aceituno, 2003).

Traditionally the study region has been divid-

Fig. 1. Study region, classic phytogeographic schemebased on Cabrera and Willink (1973). Scale bar = 400 km.

Table 1.General results for all analyses under different grid sizes, consensus criterion (%), and consensus rules (ae andaa). For more information on consensus rules and criterion see Materials and Methods.

0.2 x 0.2 0.5 x 0.5 0.5 x 1.0

25%-50% 50%-75% 10%-20% 25%-50% 10-20%-5-10% 25%-50%

Sub-sets

(number of

defning species)

72

(144)

125

(192)

783

(365)

695

(425)

958

(425)

826

(505)

ae 50% 48 64 305 264 355 286

ae 33% 39 52 211 184 248 203

ae 10% 29 40 104 106 123 92

ae 5% 28 37 87 82 92 70

aa 50% 40 48 80 65 81 64

aa 33% 25 26 29 22 7 8

aa 10% 15 17 9 7 2 2

aa 5% 14 17 9 7 2 2


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5/34


6/34


7/34


8/34


9/34


10/34


11/34


12/34


13/34


14/34


15/34


16/34
http://www.tropicos.org/


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DARWINIANA 50(2): 218-251. 2012

Distribution data without corresponding vouch-ers deposited in public herbaria were only used forsome Bolivian endemics, where we added field ob-servations from R. P. Lpez, and also when compil-

ing species distribution within the Cactaceae. TheCactaceae are particularly species rich in the studyregion (Mourelle & Ezcurra, 1996) but also one ofthe most underrepresented families in herbaria; asa result, specimens deposited in public herbaria arefar from covering the distribution of an individualspecies. Since the Cactaceae is one of the main tar-gets for commercial collectors the information oncollection sites, found at Cactus-enthusiastic home-pages, is overwhelming and in sharp contrast withthe sparse information available from traditionalacademical sources. We choose to include infor-mation from a private collector homepage (http://ralph.cs.cf.ac.uk/Cacti/finder.html). This procedurewas done after consulting a specialist on the family,Dr. Roberto Kiesling, in order to avoid species thatare not easily recognized in the field. Data from thissource were also considered only when the loca-tion, and altitude, agrees with the distribution rangedefined in the Catalogue of the Plants of the South-ern Cone (Zuloaga et al., 2008).

A total of 3262 records were compiled andgeoreferenced. This gives an unimpressive av-erage of six registers/species, which both re-flect that species were not georeferenced, in thestudy, for redundant or proximate locations, andthat endemic species of north-western Argentinaand southern Bolivia are usually rare and poorlycollected, many of them being only known fromthe type material.

All specimens without GPS recorded coor-dinates were georeferenced according to the

point-radius method of Wieczorek et al. (2004).We carefully respected the altitudes of the col-lection sites in order to extract climate data withas much accuracy as possible. All data have beensubmitted to the online version of Flora Argenti-na (http://www.floraargentina.edu.ar).

Analyses

We searched for areas of endemism using theprogram NDM/VNDM ver. 2.7c (Goloboff, 2005).

VNDM is a grid based method that identifies anarea of endemism as the congruent distributions oftwo or more species (Szumik et al., 2002; Szumikand Goloboff, 2004, 2007). The general outputs inVNDM are area sets (groups of cells in the grid)that are supported by the presence of two or more

species. Each area receives an endemism-score ac-cording to the optimality criterion developed forthe method. The optimality criterion measures thefit of each species to the area, e.g. how well each

species found within the area adjust to this. The op-timality criterion penalizes both absence in part ofthe area as well as presence in adjacent cells outsidethe area (if a species is present outside the area ina non-adjacent cell it is not considered among thespecies supporting the area). The endemism scorefor each area is the sum of the fit of the support-ing species. The endemism score is therefore influ-enced both by the number of species supporting anarea as well as the distribution of the supportingspecies within and around the area (Szumik et al.,2002; Szumik and Goloboff, 2004).

The algorithms in NDM have lately been foundto outperform other and more widespread methodsfor delimiting areas of endemism such as hierarchi-cal clustering (Carine et al., 2008; Escalante et al.,2009). One of the advantages of NDM is its abili-ty to recognize overlapping distribution patterns ifthese are defined by different species groups. Over-lapping patterns may be independent if definedby different sets of species (Szumik & Goloboff,

2004), and are to be expected when distributionanalysis are based on grids if more than one envi-ronments are found in the same cell.

Grid and cell size

As discussed by Linder (2001) the choice of gridsize is important. The use of small cells would re-sult in a finer and more detailed resolution but at thesame time increase the number of artificially emptycells where species occur but have not been record-ed. We used three different cell sizes to explore both

distribution patterns at different scale as well as therobustness of the resulting areas to changes in gridsize (Aagesen et al., 2009; Navarro et al., 2009).Grids with cell sizes 0.2x0.2, 0.5x0.5, and 0.5x-1.0 were used where 1 is approximately equal to100 km. In the last grid we used rectangular cellsrather than square cells because the north-southrunning Andes Mountains form a steep east-westaltitude gradient that causes various habitat changeswithin 100 km. The rectangular cells were used to

explore north-south running patterns of widely dis-tributed but poorly collected species without lump-ing too many habitats into the same cell.

Fill option

The problem of artificial empty cells is some-
http://ralph.cs.cf.ac.uk/Cacti/finder.htmlhttp://ralph.cs.cf.ac.uk/Cacti/finder.htmlhttp://www.floraargentina.edu.ar/http://www.floraargentina.edu.ar/http://ralph.cs.cf.ac.uk/Cacti/finder.htmlhttp://ralph.cs.cf.ac.uk/Cacti/finder.html


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what alleviated in NDM by a user defined fill op-

tion (radius size) that assumes the presence of agiven species if it has been collected close to thelimit within a neighbouring cell (Szumik & Golo-boff, 2004; Aagesen et al., 2009; Escalante et al.,2009). We used two radius sizes (see Table 1). Thesmallest radius size reflects approximately the errorof the hand georeferenced records as determined bythe point-radius method (Wieczorek et al., 2004;see Aagesen et al., 2009) while the second and wid-er radius size was used to explore dependence onthe fill options in the final areas of endemism.

Search procedure

The searches were done using default settingswith the following changes: swap two cells at atime; discard superfluous sets as they are found;replace a set if improved during swapping; pre-check duplicates; keep overlapping subsets if 20%of species unique. Searches were done by changingthe seed for each search, without replacing existingsets and deleting duplicate sets after each replicate.

This search sequence was repeated until numbersof sets were stable.

Consensus rules

As we kept all overlapping subsets if they dif-fered by 20% in species composition, we found

several area sets that were supported by 5-20 spe-

cies but differing only by one or two species. Areasets can be merged into consensus areas if they shareat least some of their defining species (Szumik &Goloboff, 2007). Two consensus rules are avail-able in VNDM. The strictest consensus rule mergesarea sets if they all share a user defined percentag-es of their defining species (in the program calledagainst every included area hereafter abbreviatedas consensus rule ae). The second more relaxed cri-terion includes an area set in a consensus if it sharesa user defined percentage of its defining species with

at least one other area set in the consensus (calledagainst any included area hereafter abbreviated asconsensus rule aa; see Aagesen et al., 2009).

Ideally, the strict consensus rule ae should beused for identifying areas of endemism as at leastsome species are shared among all the individualarea sets, thus ensuring a certain coherency withinthe area. Consensus areas derived from the laxerconsensus rule aa, are efficient to outline gradualspecies overlap between area set, but the distribu-

tion of the species defining the consensus are likelyto be found in just a small part of this. However,due to the high number of ae consensus producedby our data (Table 1) it was unfeasible to base thediscussion on the ae consensus areas only. Conse-quently, we explored areas of endemism through

Fig. 2.A,annual precipitaton in mm. B,altitude (m asl) in the study region. C, map of de Martonne aridity index. Scalebars = 400 km. Color version at http://www.ojs.darwin.edu.ar/index.php/darwiniana/article/view/435/462


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DARWINIANA 50(2): 218-251. 2012

Table

3.AreasseparatingfrommainconsensusinFig

.4,orderedaccordingtomax.areascore(gridsize0.5x0.5).Thearea

swereobtainedbygraduallyincreasingconsensus

criterionfrom5%

to50%(aeandaarefertodifferent

consensusrules).

Area

Obtained

under

0.2

x0.2

N

r.of

sub

-setsin

con

sensus

Areascore

Nr.of

Fa

milies/

G

enera/

S

pecies

Altituderange

Ar

idityrange

Fig.

Separates

fromm

ain

ar

ea

Jujuy-coreandborder

yes

101

2.1-26.3

31

/66/87

350-5100

6.2-33.7

4C

40%

aa

Tucumn

yes

17

7.3-23.3

22

/38/55

530-4800

6.3-34.5

4D

45%

aa

Salta

yes

36

2.7-13.3

14

/23/27

740-4200

5.4-36.6

4L

50%

aa

Famatina

Famatinaborder

yes

2 1

10.9-13.1

3.9-4.2

8/10/19

2/2/6

1150-4100

750-2200

4.5-15.0

7.2-11.8

4H

25%

aa

25%

aa

Yavi-SantaVictoira

yes

2

10.6-10.8

8/12/13

1700-4400

15.5-25.1

4K

25%

aa

Jujuy-Tucumn

yes

370

2.0-10.4

38

/59/85

350-5000

5.2-40.4

4E

50%

aa

Ambato

yes

24

2.4-10.3

11

/14/22

1000-3700

6.6-18.1

4M

45%

aa

BolivianPrepuna

yes

19

2.2-6.5

11

/16/21

1400-4400

6.7-26.3

4J

25%

aa

Tinogasta-Beln

yes

9

2.6-4.5

7

/8/11

1600-4300

3.1-7.3

4N

45%

aa

SanJuan

no

8

2.0-3.8

7/10/10

850-3400

3.6-15.6

4G

notpartof

mainarea

Catamarca-LaRioja

summitsanddryinnervalleys

no

19

2.0-3.8

12

/14/19

500-4500

4.8-18.6

4P

30%

aa

NOA

NOA-SanJuan

no

142

2.0-3.5

2.1-2.4

10

/19/20

4/4/4

560-4800

150-4600

3.1-29.2

4.7-19.1

4B

notpartof

mainarea

notpartof

mainarea

SouthBolivia-northNOA

no

1

3.0-3.2

4/4/2

2000-4000

6.6-19.6

4I

notpartof

mainarea

AndesLaRioja-S

anJuan

no

6

2.1-2.8

8/10/11

1000-4500

3.8-24.1

4F

notpartof

mainarea

Salta-Catamarca

summitsanddryinnervalleys

no

4

2.1-2.8

7/7/8

1500-5100

4.3-19.1

4O

45%

aa


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the laxer aa rule that produced less, and more inclu-sive consensus areas.

Environmental data and aridity

Environmental data for the study region that in-cludes both Argentina and Bolivia is limited to thedata available in WorldClim (Hijmans et al., 2005).We used the program Diva-Gis 7.4.0.1 (Hijmans etal., 2005-2010) to extract altitude, temperature, andprecipitation of the collection sites. As the collec-tion sites span from 500 m asl to 5000 m asl andan annual mean temperature from -3C to 23C weused humidity rather than rainfall when comparingdifferent sites. We adopted the aridity index of DeMartonne (1927) that can be calculated through thelimited environmental variables available for thestudy region, and furthermore provides a quantita-tive measure for the useful but somewhat impreciseterms arid, semi-arid, humid, etc.

Aridity Index of de Martonne. Accumulatedannual precipitation / (annual mean temperature +10). We use the following categories (De Martonne,1927; Almorox, 2003): 0-5: desert; 5-10: semi des-ert; 10-20: semi arid; 20-30: subhumid; 30-60: hu-

mid; >60: wet. Distribution of aridity within thestudy region is shown in Fig. 2C.

RESULTS

The results are summarized in Table 1-3. Ingeneral, the number of area sets increased withcell size, but the bigger cells also produced moreoverlapping distribution patterns that grouped intofewer consensus areas under the laxer aa rule (Ta-

ble 1). The two different fill radius produced nearlyidentical results in number of area sets and consen-sus areas, hence support for the resulting areas didnot depend on a specific fill ratio. The discussionis based on the analyses using the widest fill ratios.

Five hundred-nineteen (519) species supportedsome area under at least one grid size, while 21 spe-cies did not support any area (Table 2). Of these,eight species are only known from a single or twolocalities, while the remaining species are widely

distributed within the region.The study region has been sufficiently sampledto analyse species distribution under cell sizes0.5x0.5 where most cells of the study region areassigned to one or more areas of endemism (Fig.3A). When the cell size is reduced to 0.2x0.2 only

the cores of the main areas are recovered even ifpresence of one or more endemic species is record-ed in most cells (Fig. 3B). Consequently, we baseour discussion on the results from analysing cells of0.5x0.5. The two alternative cell sizes with eithersmaller or longer cells were only used to explorethe distributions of species that did not support dis-tribution patterns under the 0.5x0.5 grid.

When using a grid size of 0.5x0.5, the lax aa

consensus rule produced seven distribution pat-terns, under both the 5% and 10% consensus cri-terion (Table 1). About 2/3 of the endemic specieswere gathered in a single main consensus area (Fig.4A), while five distinct distributions, with a totalof 49 species, did not form part of the main pattern(see discussion below). A single area consistingof four species was considered an artefact and notdiscussed any further (the species from this patternare considered part of the complex Jujuy-Tucumn

area, see Discussion and Appendix). The remaining120 endemic species did not support any area underthis grid size.

In order to explore sub-areas of the main consen-sus area in Fig. 4. A this was decomposed by grad-ually increasing the consensus criterion. By this

Fig. 3.Areas of endemism and sample density of ende-mic species. Empty cells: presence of one or more ende-mic species in the cell. Colour lled cells: cell assigned to

one or more areas of endemism. The colour scale repre-sents areas of endemism of higher (darker) versus lower(lighter) endemism score. A, grid size 0.5x0.5. B, gridsize 0.2x0.2. Color version at http://www.ojs.darwin.edu.ar/index.php/darwiniana/article/view/435/462
http://www.ojs.darwin.edu.ar/index.php/darwiniana/article/view/435/1171http://www.ojs.darwin.edu.ar/index.php/darwiniana/article/view/435/1171http://www.ojs.darwin.edu.ar/index.php/darwiniana/article/view/435/1171http://www.ojs.darwin.edu.ar/index.php/darwiniana/article/view/435/1171


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DARWINIANA 50(2): 218-251. 2012

procedure sub-areas separate successively from themain area with those defined by less overlappingspecies separating first. We decomposed the mainarea both to extract the individual high endemic

areas as well as to assign all endemic species tosub-areas with a closer association between areaextension and distributions of the defining species(see, Consensus rules). All final sub-areas (Table 3,Fig. 4) are also found under the strictest ae consen-sus rule.

A total of 17 areas of endemism are discussedbelow. The 120 species that did not support areas inthe 0.5x0.5 grid were assigned to one of these 17areas according to results found under the 0.2x0.2or 0.5x1.0 grids (Table 2). Two areas are basedexclusively on results obtained by analysing cellssizes of 0.5x1.0; these areas were not found underthe smaller cell sizes. Only 21 species did not sup-port any of the final areas.

We have named areas of endemism according tothe political division in which the core of the areaoccurs. The political names do not indicate that theareas fit any political border or that the politicalborders have influenced the analysis. The namesare simply useful for a quick spatial orientation.

In some cases, such as Famatina and Ambato, thepolitical names coincide with the mountain rangein which the endemic species from the core areashave been found. In other cases such as Jujuy andTucumn several mountain ranges and valleys areincluded in the core of the areas with some of thesesituated in the neighbouring province Salta.

Even when subdividing the main area into sub-areas, most of the defining species will be distribut-ed only in part of the area. One example isAphelan-dra lilacinathat has only been collected in El Rey

National Park in the province of Salta. The cellincluding El Rey National Park lies in the southeasternmost low endemic part of the Jujuy borderarea (Fig. 4C). Consigning Aphelandra lilacinato the Jujuy area is therefore slightly misleading,but a necessity unless a prohibited high numberof consensus areas are shown. However, as ouraim is to provide an overview of the distributionof the endemic species in north-western Argentinawe concentrate the discussion on main distribution

patterns. Further details of the individual speciesdistribution can be consulted in the online versionof the Flora Argentina (http://www.floraargentina.edu.ar) that includes dot distribution maps and la-bel information for all specimens included in thepresent study.

DISCUSSION

The vast majority of the vascular flora endemic tothe southern part of the central Andes outlines small,successively overlapping sub-areas that combineinto a single main consensus area only under the laxconsensus rule and a very lax consensus criterion(Fig. 4A). Endemism is far from evenly distributedamong the sub-areas but declines gradually towards

the south and west of the study region. Peaks of en-demism are found near the humid Andes slopes inJujuy, Tucumn/Ambato, and to a lesser extent in theisolated Sierra de Famatina in La Rioja.

Although the main portion of the endemic spe-cies conform to the patchy distribution patterns that

Table 4.Main radiations within the study region. Onlyfamilies with 10 or more endemic species, and generawith ve or more species have been included. For the

families, the percentage of the total number of endemic

species within the region is shown.

Main families: nr. of

endemic species

Main genera: nr. of

endemic species

Asteraceae: 126 (23%)

Senecio: 39Hieracium: 10Flourensia: 9Baccharis: 8Stevia: 6

Cactaceae: 75 (14%)

Lobivia: 16Gymnocalycium: 15Trichocereus: 13Parodia: 7Tephrocactus: 6

Poaceae: 46 (8%)Nassella: 12Poa: 6

Fabaceae: 34 (6%)Lupinus: 10Adesmia: 8Astragalus: 8

Solanaceae: 29 (5%)

Solanum: 18Sclerophylax: 6

Malvaceae: 25 (5%) Nototriche:19

Bromeliaceae: 17 (3%) Puya: 9

Apocynaceae: 15 (3%) Philibertia: 8

Violaceae: 12 (2%) Viola: 12

Gentianaceae: 11 (2%) Gentianella: 11
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Fig. 4.A-L.Areas of endemism discussed in the text and in Appendix 1. The colour scale represents cells of higher(darker) versus lower (lighter) endemism score within each area. The colour scale is scaled to show max details of en-demism within each area. For max and min score within the individual areas see Table 3. A,main consensus.B,NOA.C,Jujuy, core and border.D,Tucumn.E,Jujuy-Tucumn.F,La Rioja-San Juan Andes.G,San Juan.H,Famatina.I,South Bolivia-north NOA.J,Bolivian Prepuna.K,Yavi-Santa Victoria. L,Salta core and border.


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Fig. 4.Continued. J-R.J,Bolivian Prepuna. K,Yavi-Santa Victoria. L,Salta core and border. M, Ambato. N,Tinogasta-Beln. O, Salta-Catamarca. P, Catamarca-LaRioja. Q, La Rioja-San Juan. R, Valle Fertil. Color ver-sion at http://www.ojs.darwin.edu.ar/index.php/darwi-niana/article/view/435/462

form the consensus in Fig. 4A, the southern part ofthe central Andes can still be recognized as a singlearea of endemism, defined by at least 53 speciesthat are widely distributed within the region (the

NOA area in Fig. 4B).Here we discuss taxonomic composition and

habitat of the endemic species from the study re-gion in general, as well as the individual main dis-tribution areas such as the general NOA pattern andsub-areas of the main consensus in Fig. 4A. Sub-ar-eas were separated from the main consensus bygradually raising the consensus criterions, whichcauses sub-areas to separate successively. A total of18 different sub-areas were identified (Table 2-3)among which we discuss selected high-endemic ar-eas. A description of the remaining areas is foundin Appendix 1.

Altitude and Aridity

Our results indicate that 473 of the endemic spe-cies, nearly 90%, have been collected at middle alti-tudes between 1500-3500 m asl (Table 2), a patternthat is consistent with the notion that Prepuna slopevegetation harbours the main part of the endemic

species. Only 40 species are restricted to altitudesbelow 1500 m asl while 33 species are restricted tohigh Andean environments above 4000 m asl (main-ly from the genera SenecioL., NototricheTurcz.,and ViolaL.). The relative low number of endem-ic high Andean species is perhaps unexpected andmay be underestimated as collection of high Ande-an localities above 4000 m asl are sparse. However,part of the high Andean flora were left out of theanalyses as it is shared with the neighbouring Chile.

In accordance with the general arid climate

of the central Andes, the semi-arid environments(AI=10-20, Fig. 2C) appear as the principal habitattype for the endemic species. Semi-arid environ-ments harbour about 80% of the endemic flora with30% (159 species) being restricted to this habitattype. Semi-arid environment are mostly extend-ed at lower altitudes (compare Fig. 1 and 2A), butonly 14 endemic species are restricted to altitudesbelow 1000 m asl (Table 2). Consequently the rel-atively narrow band of semiarid habitats between

1500-3500 m asl (compare Fig. 2 B and C) includesthe main portion of the endemic species, makingthe topographic complex plateau, slope, and valleysystem of the southern central Andes the main loca-tions for endemism.

As few as 36 species are restricted to subhumid
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or humid environments (AI=20-60, Fig. 2C) indi-cating that the diverse Tucumano-Bolivian Yun-gas forest is surprisingly poor in endemic speciesat a local scale. This is in accordance with Ibisch

et al. (2003) who considered the endemism of theTucumano-Bolivian Yungas to be unimportant at alocal Bolivian scale and moderate at the inclusivescale considering the Tucumano-Bolivian Yungasforests in their entire extension. The Bolivian-Pe-ruvian Yungas forests were in contrast consideredthe main area of endemism for Bolivia. Endemismin the south-western Bolivia were, as in the presentstudy, mainly found in the Prepuna vegetation andin the arid interandean forests (Ibisch et al., 2003).In this study the mountain grasslands above thetree line are rich in local endemics [note that thesegrasslands were considered the highest strata of theYungas by Cabrera (1976), while we follow Ibischet al. (2003) who included these grasslands in thesubhumid Puna restricting the term Tucumano-Bo-livian Yungas to forest vegetation].

Local endemics are also nearly lacking fromdesert environments with only seven speciesfound exclusively in habitats with an aridityindex below 5 (Table 2). Although desert envi-

ronments are found throughout the study region,they become part of the distribution pattern onlyin the areas that include patches of desert cli-mate separated from the Andes (i.e. in the Cata-marca, La Rioja, and San Juan provinces Table3, Fig. 2C). Only a single species, Gentianellapunensis, is collected above 3500 m asl whereit is endemic to vegas in the deserts of northernSalta. Dry adapted endemic desert species areconsequently restricted to desert parches of mid-dle or low altitudes, such as the inner basins of

the Andes that are covered by Monte vegetation.High Andean desert environments are commonon both sites of the Andes in the northern partof the study region (compare Fig. 2 B and C),hence desert endemics may be lacking from thenorthern areas because the endemic species areshared between Argentina and Chile, hence ex-cluded from our analyses.

Taxonomic groups

The Asteraceae outnumbers all other familiesin the region, with 121 endemic species from 35genera (Table 2 and 4); furthermore, it is the onlyfamily with endemic species supporting all areas(except Valle Frtil - Fig. 4R). The endemic Aster-aceae are found in all environments ranging from

species restricted to humid habitat (e.g., Mikaniasiambonensisand Vernonianovarae), to desert en-vironment (e.g., Senecio lilloi), and from strict highAndean (e.g., Senecio kunturinusand S. delicatu-

lus) to lowland species (e.g.Eupatorium tucuman-enseandIsostigma molfinianum).

Nearly 1/3 of the endemic Asteraceae belong tothe genus Seneciowith 39 endemic species in thestudy region twice as many species as the sec-ond most common generaLobiviaBritton & Rose(Cactaceae),Nototriche(Malvaceae), and SolanumL. (Solanaceae) (see Table 4). Nonetheless, the re-maining 2/3 of the endemic Asteraceae are highlydiverse belonging to 16 of approx. 48 Asteraceaetribes (Funk et al., 2009), the most numerous beingthe Astereae Cass., Eupatorieae Cass., and Helian-theae Cass. including 17, 13, and 10 species each.

Although both the origin and early diversifica-tion of the Asteraceae are likely to have occurredin southern South America (Funk et al., 2009) themain radiations of Asteraceae within the study re-gion belong to clades that are principally found inthe northern hemisphere, e.g., Senecio,HieraciumL.,Flourensia DC.,Baccharis L., and SteviaCav.(see Funk et al., 2009 for biogeography of the fam-

ily). Still, all tribes from the basal Asteraceae grade(Mutisieae s. l. sensu Cabrera; Ortiz et. al. 2009)are represented, although in lower numbers, amongthe local endemic species, with Hyalideae Panerobeing the only exception. The Asteraceae endem-ics are consequently not only numerous within theregion but also phylogenetically diverse, both re-flecting the general family trend of being especial-ly diverse in arid environments (Funk et al., 2009)as well as the fact that the Asteraceae is the mostdiverse family both in number of genera and spe-

cies within the southern cone (Zuloaga et al., 1999;Moreira-Muoz & Muoz-Schick, 2007).

Cactaceae is the second most numerous fami-ly with 74 endemic species and 15 genera withinthe study region (Table 3). Unlike the Asteraceaethe main part of the endemic Cactaceae belong toa single clade (55 species), the tribe Trichoceree-ae Buxb. that principally consists of high Andeanspecies from the eastern slopes of the central An-des (Ritz et al., 2007, Hernndez-Hernndez et al.,

2011). The remaining Cactaceae species are eitherclose relatives to the Trichocereeae from the CoreCactoideae II clade that also includes the Tricho-cereeae (Hernndez-Hernndez et al., 2011) orfrom early diverging lines of the subfamily Opunti-oideae (Griffith & Portery, 2009).


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Like the Asteraceae, the Cactaceae are consid-ered to be of South American origin with the ear-ly diversification of the tribes Trichocereeae andOpuntioideae situated in the Central Andes (Nyf-

feler, 2002; Edwards et al., 2005; Griffith & Porter2009). While the extreme succulence of most Cac-taceae species makes the family well adapted to thearidity of the southern central Andes, the Cactaceaeendemics occupy nearly as wide an array of hab-itats as the Asteraceae including strict Altoandinespecies restricted to altitudes above 4000 m (Lobiv-ia marsoneri), with endemic species only lackingfrom the most humid part of the study region.

Following Asteraceae, Poaceae is the secondmost diverse family in the southern cone (Zulo-aga et al., 1999) and reaches the study region asthe third most numerous family with 45 endemicspecies from 20 different genera (Table 3). The en-demic species belong to both of the main Poaceaeclades, the BEP and the PACMAD clades (GPWG2001; Snchez-Ken et al., 2007; GPWG II, 2012).The BEP clade generally appears in colder climatesthan the PACMAD clade (Edwards & Smith, 2010),and it is more species rich in the study region, with34 endemic species versus 11 from the PACMAD.

Like Asteraceae, the endemic Poaceae speciesare found in most of the available habitat types (seeTable 2) with two species restricted to subhumidor humid environments (Aristida pedroensis andChusquea deficiens), high Andean species restrict-ed to altitudes above 4000 m asl (Anatherostipahenrardiana and Poa nubensis) and lowland spe-cies only found below 1000 m asl (e.g., DigitariacatamarcensisandNeobouteloua paucirracemosa).Only strict desert endemics are lacking although asingle species from semi-desert environments enter

desert habitats (Pappostipa hieronymusii).In addition to the main families discussed above,

the Solanaceae and Malvaceae both include generawith considerable radiations within the region. Thegenus Solanumwith 18 endemic species occupiesa wide array of habitats from semi-arid to humidenvironments between 500 and 4000 m asl. Severalof the Solanumendemics reach sub-humid and hu-mid sites, with four of the species restricted to thesehabitats, while desert environments are occupied

by another Solanaceae genus, SclerophylaxMierswith six endemic species in the region (Table 2).As opposed to the taxa mentioned above, the

radiation ofNototriche(Malvaceae) is exclusivelyhigh Andean, with all 19 endemic species found insemi-desert to semi-arid environments above 4000

m asl. Other well documented high Andean radia-tions such as GentianellaMoench,LupinusL., andValerianaL. (von Hagen & Kadereit, 2001; Bell &Donoghue, 2005; Hughes & Eastwood, 2006) are

less important in the region with eleven, seven, andfive endemic species, all found at lower altitudesthanNototriche.

Main areas of endemism

The NOA (Nor-Oeste-Argentina) area. The NOAarea (Fig. 4B) is the general area of endemism forthe southern part of the central Andes. The area issupported by species that are widely distributedwithin the study region and overlaps with all be-low mentioned sub-areas segregated from the mainconsensus in Fig. 4A. Four species reach the southof San Juan (Table 2) and consequently define aslightly wider pattern than the NOA area shown inFig. 4B.

The northern limit of the NOA area coincideswith the political border between Argentina andBolivia hence the pattern probably extends intosouthern Bolivia. However, the scarcity of inten-sive botanical explorations in this part of Bolivia

prevents us to speculate on the exact northern lim-it of the NOA pattern. So far among the definingNOA species only Mirabilis bracteosa, Mutisiakurtzii, and Trichocereus terscheckii have beencollected in Bolivia, but endemic Argentinean taxawidely distributed in Jujuy are most probably alsopresent in southern Bolivia.

Since the distribution pattern spans approxi-mately 1000 km from north to south, the pattern isunsurprisingly not recovered when using cell sizesof 0.2x0.2, a feature that requires collection sites

every 20 to 40 km depending on the settings of thefill option (see Material and Methods). The NOApattern emerges when using cell sizes of 0.5x0.5in which case 24 species are sufficiently well col-lected to define the area (Table 2). Other common,but less frequently collected species such as thecolumnar cactus Trichocereus terscheckii, supportthe north-south running pattern when the grid ischanged to a cell size of 0.5x1.0, allowing foreven wider distances between the collecting sites.

A total of 54 species support the area when using acell size of 0.5x1.0 (Table 2).All NOA endemics are found in desert, semi-des-

ert and semi-arid habitats with several species alsoreaching either desert or sub-humid sites. Humidenvironments are not part of the pattern, which


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is consistent with the north-southern range of thearea, e.g. the distributions of the defining speciesthat reach out of the region where the humid hab-itats are found. Consequently, the moist requiring

species are restricted to the northern portion of thestudy region and support sub-areas in Fig. 4A butnot the general NOA pattern. The broader distribu-tion pattern reaching San Juan is slightly dryer anddoes not include sub-humid habitats.

The NOA pattern includes all altitudinal layersof the vegetation as the defining species are foundfrom 500 m to above 4500 m asl. However, slopesvegetation seem to be an important part of the dis-tribution pattern as all species appear between 1500m and 3500 m asl. Most species have broad rangeswith some ranging nearly 3000 m asl (e.g. Oxal-is famatinae see Table 2). The highest part of theNOA pattern is defined by species restricted to highAndean vegetation above 3000 m asl (e.g., Muli-num famatinense and Pycnophyllum convexum).The lowest part of the distribution pattern includesseveral plants that are common to Monte vegetation(Cabrera, 1976) and is delimited by Tephrocactusweberi that is found between 500-2000 m asl indesert and semi-desert habitats.

Several of the species that define the NOA pat-tern are common elements in the vegetation of thestudy region. These include the bushes Bulnesiaschickendantzii, Plectocarpa rougesii (Zygophyl-laceae), Mutisia kurtzii, and Cersodoma argenti-na (Asteraceae), as well as the grasses Panicumchloroleucum and Sporobolus maximus. Commonbut less frequently collected species that supportthe north-south running pattern when the grid ischanged to cell size 0.5x1.0, include the colum-nar cactus Trichocereus terscheckii, the opuntioid

cactus Tephrocactus weberi, the cushion formingBromeliaceae Deuterocohnia haumanii and Hier-onymiella marginata(Amaryllidaceae) (Table 2).

High endemic areas: Jujuy, Tucumn, and Ju-

juy-Tucumn. Within the study region, the cells ofhighest endemism score include the cores of theJujuy area, the Tucumn area, and the combinedJujuy-Tucumn area (Fig. 4C-E). These three areasare jointly supported by nearly 30% of the endemic

species found in the region, and are furthermore byfar the most diverse both in number of genera andfamilies (Table 2). When also considering the spe-cies that define the diffuse border of the core areas(Fig. 4C, Table 2), about 45% of the endemic spe-cies are confined to these three distribution patterns

that undoubtedly form the main area of endemismin the southern cone east of the Andes.

Common for the cores of both the Jujuy andTucumn areas are that they include some of the

study regions most variable cells both in terms ofaltitude, temperature, and precipitation. The avail-able habitats within these areas range through allphytogeographic unites described for north-west-ern Argentina (Cabrera, 1976). While variability intemperature and altitude do not decline along thenorth-south gradient of the study region, amount ofrainfall does decline (Fig. 2A). Humid sites with anaridity index above 30 are mainly found at the east-ern Andean slopes in both the Jujuy and Tucumnareas (Fig. 2C). Consequently, endemic speciesfrom humid environments, such as the subtropicalTucumano-Bolivian Yungas forests are only foundin the three high endemic areas (Table 2). Neverthe-less, and although the Tucumano-Bolivian Yungasforest is one of the most diverse phytogeographicunits in Argentina (Cabrera, 1976; Zuloaga et al.,1999 ), it should be noted that only twelve speciesare restricted to humid sites in the present study(Table 2), indicating that the Yungas vegetation in-cludes few endemic species at this local scale. The

main part of the endemic species are distributedthrough the broad array of available habitats both interms of altitude and aridity (Table 3), with no spe-cies occupying the entire range (Table 2).Variabil-ity in precipitation rather than high rainfall mighttherefore be the main factor that causes high levelof endemism within the Jujuy and Tucumn areas.

The decline in endemism in the center of theJujuy-Tucumn area is consistent with the patternsfound in general diversity studies (Szumik et al.,2012), and distribution maps of the Yungas forest

(Hawkes & Hjerting, 1969; Cabrera, 1976; Brown,1995). It is unclear whether the decline in diversityand endemism is caused by lack of collections orwhether some habitats - e.g., humid high Andeangrasslands - are lacking in this part of the area.

Minor areas of endemism: San Juan, Famatina,

and south-western Bolivia. Several minor areas ofendemism separate from the general area consensus

in Fig. 4A. Here we discuss two southern most areasin San Juan, the central Famatina area, as well asan area related to the vegetation in south-westernBolivia. The full list of areas is found in Appendix 1.

San Juan: Two areas of endemism are definedby species restricted to the southern most part of the


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study region, the Andes of La Rioja-San Juan (Fig.4F) and the San Juan area (Fig. 4G, Table 2). Thesetwo areas are well defined and do not combinewith the general consensus area even under very

lax consensus criteria, hence the areas do not sharespecies with any of the other areas of endemism.This distinct distribution pattern of the endemicspecies from the southern part of the study regionmay reflect that the San Juan areas lie close to thelimit of the Patagonian phytogeographic unit sensuCabrera (1976), hence close to a general change invegetation types that is widely recognized amongbiogeographers (e.g., Olson et al. 2001; Morrone,2006). The San Juan areas are among the most aridareas within the study region. Although some of thespecies that define the Andes area of La Rioja-SanJuan (Fig. 4F) reach sub-humid locations accordingto Table 2, these sub-humid locations fall at siteswhere the annual mean temperature is below 0 Crather than at sites with high rainfall (note that forthe same annual precipitation the aridity index ofde Martonne will increase with falling mean annualtemperature).

Famatina. The Famatina areas both separatefrom the main area when raising the consensus cri-

terion to 25% (Fig. 4H). The two partly overlap-ping areas include a highly endemic area of speciesfound mainly above 1500 m asl as well as a lowendemic border area of species found at lower alti-tudes. The areas do not share species, hence, theseareas do not combine into a single consensus area.Combined both Famatina areas are supported by 28endemic species found in desert/semi-desert andsemi-arid environments between 700 m and 4000m asl.

The area with highest endemism score contains

primarily the isolated Nevados de Famatina thatreaches above 6000 m asl. Mining activity at 4.600m asl has ensured long standing accessibility to thehigh peaks where botanical exploration has beenrelatively constant since the late 19thcentury. TheFamatina is, consequently, one of the best sampledhigh Andean locations south of the high-endemicareas in Jujuy and Tucumn. Nonetheless, Fama-tina is defined by much less endemic species thanthe areas Jujuy and Tucumn. Furthermore, diver-

sity within this area is low as more than half of theendemic species belong to three of the most speciesrich radiations within the study region: Senecio,Nototricheat altitudes above 3000 m asl, and Gym-nocalycium Pfeiff. ex Mittler in the border area(Fig. 4H) below 2000 m asl.

South-western Bolivia-northern Argentina. To-wards the northern part of the study region fourspecies delimit a shared, well defined Bolivian-Ar-gentinean area that do not combine with any other

distribution pattern even under very lax consensuscriteria (Fig. 4I, Table 2-3). The area overlaps part-ly with the NOA pattern (Fig. 4B) but stretchesfurther north into Bolivia. The Bolivian portion ofthis area corresponds to the Bolivian Prepuna as de-fined by Lpez (2000) while the Argentinean partonly includes the northern most part of the Prepunaprovince sensu Cabrera (1976). The area defined inFig. 4I includes semi-desert and semi-arid habitatsbetween 200-4000 m. When increasing the cell sizeto 0.5x1.0 two additional species (Deuterocohniastrobiliferaand Oxalis cotagaitensis) are incorpo-rated into the area.

Although only six species support the Boliv-ian-Argentinean area, our study did not sampleexhaustively this region, therefore it is most likelythat other species share a similar distribution pat-tern. According to the Catalogue of the Plants ofthe Southern Cone (Zuloaga et al., 2008) at least 70species are distributed from Salta to Bolivia manyof which may approximately fit the area in Fig. 4I.

This distribution pattern stresses the similarity be-tween the flora of southern Bolivia and north-west-ern Argentina as mentioned by Lpez (2000, 2003),but further sampling within the region is needed toestablish the size and importance of the area.

The Bolivian Prepuna, sensu Lpez (2000),is nested within the above south-western Boliv-ia-northern Argentina distribution pattern but com-bined with the main distribution pattern shown inFig. 4A. The Bolivian Prepuna segregates from themain area in Fig. 4A when the consensus criterion

is raised to 25% or higher (Fig. 4J). The BolivianPrepuna is formed by two overlapping distributionpatterns one of which enters northern Jujuy (Argen-tina). Both patterns are supported by species thatare mainly found in semi-arid environments from2500 m up to 4000 m asl with the highest collec-tion sites lying in the Argentinean side of the pat-tern. Since we did not compile an exhaustive list ofspecies endemic to southern Bolivia, the BolivianPrepuna may also be supported by more species

that those included in our study.Phytogeographic divisions: the Prepunaprovince and areas of endemism

Although Cabrera aimed to base his classic phy-togeographic scheme on the presence of endem-


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ic taxa from family to species level (Cabrera 1951,1953, 1976), the system was not based on quantitativestudies and did not apply consistent criteria for defin-ing the individual phytogeographic units (Ribichich,

2002). It is therefore not surprising that quantitativeanalyses, based on endemic species distribution, re-sult in areas of endemism that do not correspond toCabreras phytogeographic divisions. In our analysesall areas were defined by species from a wide array ofaltitudes in most cases including lowland, slopes, andhigh Andean species (Table 2). Moreover, as the areaswith highest endemism were found in regions whereseveral climatic regimes meet (Jujuy and Tucumn),they include several phytogeographic units withinshortest distances of each other. As a result, the spe-cies that define the high endemic areas are just asvariable as the areas themselves in their altitude andaridity ranges (Table 2).

Cabrera (1976) defined the Prepuna province asxeric slope vegetation with emphasis on the dis-tribution of emblematic species such as columnarcacti and cushion forming Bromeliaceae species,mentioning several species from different familiesas common on the slopes. Lpez (2000, 2003) laterextended the Prepuna to include a similar xeric veg-

etation in the south-western Bolivia. The Prepuna,which is here included in its entire extension, doesnot appear among the resulting areas of endemism,hence the Prepuna province sensu Cabrera (1976) isnot definable simply by the presence of two or moreunique Prepuna species.

The partly overlapping south-western Bolivia/northern NOA and the NOA area (Figs. 7 and 12)cover geographically the Prepuna in its entire exten-sion. Both areas are defined by several of Cabreras(1976) Prepuna species including columnar cacti

and cushion forming Deuterocohnia Mez species.Notably three of the species mentioned by Cabre-ra: Aphylloclados spartioides, Cercidiumandicola,and Prosopis ferox define the joint Southern-Bo-livia/northern NOA (Fig. 4I) supporting the north-ern Prepuna as delimited by Lpez (2000, 2003) inwhich the Bolivian Prepuna separates as an indepen-dent area of endemism (Fig. 4J). Columnar Tricho-cereus (A. Berger) Riccob. species define both theBolivian Prepuna and the NOA area while most of

Cabreras (1976) remaining Prepuna species supportthe NOA area. The NOA distribution pattern does,however, also include species from other altitudestrata, hence, although it appears to include thePrepuna it defines a broader area of endemism in thesouthern central Andes.

CONCLUSIONS

Located in the center of the South Americandry diagonal, the aridity of southern central An-

des is reflected in the distribution of its endem-ic vascular flora. Of 540 endemic plant species,more than 2/3 are restricted to semi-desert andsemi-arid habitats including some of these re-gions main radiations, such as the ultra high An-deanNototriche(Malvaceae) and the radiation ofGymnocalycium (Cactaceae) found below 2000m. Even the 39 endemic species from the cosmo-politan genus Senecio (Asteraceae) are almostexclusively found in semi-desert or semi-aridhabitats with only two species entering subhu-mid or humid locations.

The distributional bias of the endemic spe-cies towards arid sites is in contrast with that ofvascular plant diversity in the region, since theTucumano-Bolivian Yungas forests, on the hu-mid eastern Andes slopes, undoubtedly includethe most diverse vegetation of the region (Brown,1995; Ibisch et al., 2003). The Tucumano-Boliv-ian Yungas forests in north-western Argentinaare, however, a patch of a more extensive area of

endemism whose northern limit is found southof the Andes bend at approx. 18S (Ibisch et al.,2003). Emblematic Yungas species, such asJug-lans australis Griseb., Podocarpus parlatoreiPilg, and Duranta serratifolia (Griseb.) Kuntzeappear to be endemic to the Tucomano-BolivianYungas. Other species such as Alnus acuminataKunth andFuchsia bolivianaCarrire are widelydistributed along the eastern slopes and furthernorth to Mexico. These forests may consist ofseveral nested or partly overlapping distribution

patterns as is the case of the endemic vegetationof the arid slopes of the southern central Andes.Any attempt to evaluate endemism of the Tuco-mano-Bolivian Yungas should include these for-ests in their entire extension.

Although the Yungas forests are of little impor-tance for endemisms at the scale of our study, thehigh endemic areas of the region lies in juxtaposi-tion, west of the main rainfall zones (Fig 1a). Theendemic species of these areas are found in a broad

and variable range of aridity and altitude (Table 2),hence, rather than high rainfall itself, the gradualdecreasing rain-veil west of the main rainfall zonecaused by the complex topography of the region,may be the main factor allowing for the elevatednumber of endemic species to coexist in these areas.


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We did not find any relationship between themain areas of endemism and phytogeographic unitspreviously defined, as the main areas of endemismappeared in cells that included a widest array of

habitats. The Prepuna province sensu Cabrera(1976) and Lpez (2000, 2003) was not defined bythe endemic species as a unit; instead, two partlyoverlapping areas covered the entire extension ofthe Prepuna (Figs. 6 and 14). Both areas includeseveral Prepuna characteristics sensu Cabrera(1976). Nevertheless, of these two areas, the NOAarea should be considered a general area of ende-mism for the southern central Andes since it alsoincluded high Andean and lowland species.

ACKNOWLEDGEMENTS

We thank Claudia Szumik for helpful discussionsand support. We also thank the staff at The Lillo Foun-dation (Tucumn) as well as Dr. Beck and the staff atthe National Herbaria of Bolivia for help and hosting usduring our visits to these Institutes. We also thank thestaff at IBODA for the identification of all newly collect-ed material, and Fernando Biganzoli for accompanying

us on several collecting trips. We gratefully acknowledgeGBIF and John Wieczorek for the georeferencing work-shop in Buenos Aires. CONICET (PIP-CONICET 0207)and National Geographic (Grant N 8862-10) funded theproject and field collections respectively.

BIBLIOGRAPHY

Aagesen, L.; C. A. Szumik; F. O. Zuloaga & O. Morrone. 2009.

Quantitative biogeography in the South America highlands recognizing the Altoandina, Puna and Prepuna through the

study of Poaceae. Cladistics25: 295-310.

Almorox, J. 2003. Climatologa aplicada al medioambiente y

Agricultura. Monografa del Depto. de Edafologa. Madrid:

Universidad Politcnica de Madrid.

Arroyo, M. T. K.; R. Rozzi; J. A. Simonetti; P. Marquet & M. Sa-

laberry. 1999. Central Chile, en R. A. Mittermeier, N. Myers,

P. Robles Gil & C. Goettsch Mittermeier (eds.),Hotspots:

Earths Biologically Richest and Most Endangered Terrestri-

al Ecorregions, pp. 161-171. Mxico: CEMEX.

Arroyo, M. T. K.; P. Marquet; C. Marticorena; J. Simonetti; L.A. Cavieres; F. A. Squeo & R. Rozzi. 2004. Chilean winter

rainfall - Valdivian forests, en R. A. Mittermeier, P. Robles,

M. Hoffmann, J. Pilgrim, T. Brooks, C. Goettsch-Mittermei-

er, J. Lamoreux & G. A. B. da Fonseca (eds.),Hotspots Re-

visited: Earths Biologically Richest and Most Endangered

Terrestrial Ecoregions, pp. 99-103. Mxico: CEMEX.

Bannister, J. R.; O. J. Vidal, E. Teneb & V. Sandoval. 2012. Lati-

tudinal patterns and regionalization of plant diversity along a

4270-km gradient in continental Chile.Austral Ecology37:

500-509.

Bell, C. D. & M. J. Donoghue. 2005. Phylogeny and biogeogra-

phy of Valerianaceae (Dipsacales) with special reference to

the South American valerians. Organism, Diversity & Evo-

lution5: 147-159.

Bianchi, A. R. & S. C. Cravero. 2010.Atlas climtico digital de

la Repblica Argentina. Salta: Instituto Nacional de Tecno-

loga Agropecuaria.

Brown, A. D. 1995. Fitogeografa y conservacin de las selvas

de montaa del noroeste de Argentina, en S. P. Churchill, H.

Balslev, E. Forero & J. L. Luteyn (eds.), Biodiversity andConservation of Neotropical Montane Forests, pp. 663-672.

New York: The New York Botanical Garden.

Cabrera, A. L. 1951. Territorios togeogrcos de la Repblica

Argentina.Boletn de la Sociedad Argentina de Botnica4:

2165.

Cabrera, A. L. 1953. Esquema togeogrco de la Repblica Ar-

gentina.Revista del Museo Eva Pern, Botnica8: 87168.

Cabrera, A. L. 1976. Regiones togeogrcas argentinas.Enci-

clopedia Argentina de Agricultura y Jardinera, vol. 2, parte

1. Buenos Aires: ACME.

Cabrera, A. L. & A. W. Willink. 1973. Biogeografa de Amrica

Latina. Serie de Biologa OEA. Monografa13: 1117.

Carine, M. A.; C. J. Humphries, I. R. Guma, J. A. Reyes-Betan-

cort & A. Santos Guerra. 2008. Areas and algorithms: eval-

uating numerical approaches for the delimitation of areas

of endemism in the Canary Islands archipelago. Journal of

Biogeography36: 593-611.

Crisp, M.; S. Laffan, H. P. Linder & A. Monro. 2001. Ende-

mism in the Australian ora. Journal of Biogeography 28:

183198.

de Martonne, E. 1927. Regions of interior-basin drainage. Geo-graphical Review17: 397-414.

Edwards, E. J.; R. Nyffeler & M. J. Donoghue. 2005. Basal cac-

tus phylogeny: implicactions of Pereskia (Cactaceae) par-

aphyly for the transition to the cactus life form. American

Journal of Botany92: 1177-1188.

Edwards, E. J. & S. A. Smith. 2010. Phylogenetic analyses re-

veal the shady history of C4grasses.Proceedings of the Na-

tional Academy of Sciences107: 2535-2537.

Escalante, T.; C. A. Szumik & J. J. Morrone. 2009. Areas of en-

demism of Mexican mammals: reanalysis applying the opti-

mality criterion. Biological Journal of the Linnean Society98: 468-478.

Funk, V. A.; A. A. Anderberg, B. G. Baldwin, R. J. Bayer, M.

Bonifacino, I. Breitwieser, L. Brouillet, R. Carbajal, R.

Chan, A. X. P. Coutinho, D. J. Crawford, J. V. Crisci, M.


30/34247


O. Dillon, S. E. Freire, M. Galbany-Casals, N. Garcia-Jacas,

B. Gemeinholzer, M. Gruenstaeudl, H. V. Hansen, S. Him-

melreich, J. W. Kadereit, M. Kllersj, V. Karaman-Castro,

P. O. Karis, L. Katinas, S. Keeley, N. Kilian, R. T. Kimball,

T. K. Lowrey, J. Lundberg, R. J. McKenzie, T. Mesn, M.

E. Mort, B. Nordenstam, C. Oberprieler, S. Ortiz, P. B. Pel-

ser, C. P. Randle, H. Robinson, N. Roque, G. Sancho, J. C.

Semple, M. Serrano, T. F. Stuessy, A. Susanna, M. Unwin,

L. Urbatsch, E. Urtubey, J. Valls, R. Vogt, S. Wagstaff, J.

Ward & L. E. Watson 2009. Compositae metatrees: the next

generation, en V. A. Funk, A. Susanna, T. F. Stuessy & R.

Bayer (eds.), Systematics, evolution and biogeography of the

Compositae, pp. 747-777. Vienna: International Association

for Plant Taxonomy.

Goloboff, P. 2004. NDMVMDM, programs for identication of

areas of endemism. Program and documentation. Availableat http://www.zmuc.dk/public/phylogeny/endemism .

Grass Phylogeny Working Group. 2001. Phylogeny and subfa-

milial classication of the grasses (Poaceae).Annals of the

Missouri Botanical Garden88: 373457.

Grass Phylogeny Working Group II. 2012. New grass phylogeny

resolves deep evolutionary relationships and discovers C4

origins.New Phytologist193: 304312.

Grifth, M. P. & J. M. Porter. 2009. Phylogeny of Opuntioideae

(Cactaceae). International Journal of Plant Sciences 170:

107-116.

Hawkes, J. G. & J. P. Hjerting. 1969. The potatoes of Argenti-

na, Brazil, Paraguay, and Uruguay a biosystematic study.

Oxford: Clarendon Press.

Hernndez-Hernndez, T.; H. M. Hernndez, J. A. De-Nova, R.

Puente, L. E. Eguiarte & S. Magalln. 2011. Phylogenetic

relationships and evolution of growth form in Cactaceae

(Caryophyllales, Eudicotyledoneae). American Journal of

Botany98:44-61.

Hijmans, R. J.; S. E. Cameron, J. L. Parra, P. G. Jones & A. Jar-

vis. 2005. Very high resolution interpolated climate surfaces

for global land areas.International Journal of Climatology25: 1965-1978.

Hijmans, R. J.; L. Guarino, A. Jarvis, R. OBrien, P. Mathur, C.

Bussink, M. Cruz, I. Barrantes & E. Rojas. 2005-2010. DI-

VA-GIS, manual and program http://www.diva-gis.org

Hughes, C. & R. Eastwood. 2006. Island radiation on a conti-

nental scale: exceptional rates of plant diversication after

uplift of the Andes.Proceedings of the National Academy of

Sciences103: 10334-10339.

Ibisch, P.L.; S.G. Beck, B. Gerkmann & A. Carretero. 2003. La

diversidad biolgica: ecorregiones y ecosistemas, en P. L.

Ibisch & G. Mrida (eds.),Biodiversidad: La Riqueza de Bo-livia, pp. 47-88. Santa Cruz de la Sierra: Editorial Fundacin

Amigos de la Naturaleza (FAN).

Kier, G.; J. Mutke, E. Dinerstein, T. H. Ricketts, W. Kper, H.

Kreft & W. Barthlott. 2005. Global patterns of plant diver-

sity and oristic knowledge. Journal of Biogeography 32:

11071116.

Linder, H. P. 2001. Plant diversity and endemism in sub-Saharan

tropical Africa.Journal of Biogeography28: 169-182.

Lpez, R. P. 2000. La prepuna boliviana. Ecologa en Bolivia

34: 45-70.

Lpez, R. P. 2003. Diversidad orstica y endemismo de los va-

lles secos bolivianos.Ecologa en Bolivia38: 27-60.

Lpez, R. P. & S. Beck. 2002. Phytogeographical afnities and

life form composition of the Bolivian Prepuna. Candollea

57: 77-96.

Lpez, R. P.; D. L. Alczar & M. J. Maca. 2006. The arid and

dry plant formations of South America and their oristic

connections: new data, new interpretation?Darwiniana44:

18-31.

Montecinos, A. & P. Aceituno. 2003. Seasonality of the EN-SO-related rainfall variability in central Chile and associated

circulation anomalies.Journal of Climate16: 281-296.

Moreira-Muoz, A. & M. Muoz-Schick. 2007. Classication,

diversity, and distribution of Chilean Asteraceae: implica-

tions for biogeography and conservation.Diversity and Dis-

tributions13: 818-828.

Morrone, J. J. 2001.Biogeografa de Amrica Latina y el Cari-

be, vol. 3, 148 pp. Zaragoza: SEA.

Morrone, J. J. 2006. Biogeographic areas and transition zones of

Latin America and the Caribbean Islands based on panbioge-

ographic and cladistic analyses of the entomofauna. Annual

Review of Entomology51: 467-494.

Mourelle, C. & E. Ezcurra. 1996. Species richness of Argentine

cacti: a test of biogeographic hypotheses.Journal of Vegeta-

tion Science7: 667-680.

Navarro, F. R.; F. Cuezzo, P. A. Goloboff, C. Szumik, M. Liz-

arralde de Grosso & G. Quintana. 2009. Can insect data be

used to infer areas of endemism? An example from the Yun-

gas of Argentina. Revista Chilena de Historia Natural 82:

507-522.

Nyffeler, R. 2002. Phylogenetic relationships in the Cactus fam-ily (Cactaceae) based on evidence from trnK/matKand trnL-

trnFsequences.American Journal of Botany89: 312-326.

Olson, D. M.; E. Dinerstein, E. D. Wikramanayak, N. D. Bur-

gess, G. V. N. Powell, E. C. Underwood, J. A. DAmico, I.

Itoua, H. E. Strand, J. C. Morrison, C. J. Loucks, T. F. All-

nutt, T. H. Ricketts, Y. Kura, J. F. Lamoreux, W. W. Wetten-

gel, P. Hedao & K. R. Kassem. 2001. Terrestrial Ecoregions

of the World: A New Map of Life on Earth.BioScience51:

933-938.

Orme, C. D. L.; R. G. Davies, M. Burgess, F. Eigenbrod, N.

Pickup, V. A. Olson, A. J. Webster, T.-S. Ding, P. C. Rasmus-sen, R. S. Ridgely, A. J. Statterseld, P. M. Bennett, T. M.

Blackburn, K. J. Gaston & I. P. F. Owens. 2005. Global hot-

spots of species richness are not congruent with endemism or

threat.Nature436: 1016-1019.
http://www.zmuc.dk/public/phylogeny/endemismhttp://www.diva-gis.org/http://www.diva-gis.org/http://www.zmuc.dk/public/phylogeny/endemism


31/34248

DARWINIANA 50(2): 218-251. 2012

Ortiz, S.; M. Bonifacino, J. V. Crisci, V. A. Funk, H. V. Hansen,

D. J. N. Hind, L. Katinas, N. Roque, G. Sancho, A. Susanna

& C. Tellera. 2009. The basal grade of Compositae: Mut-

isieae (sensu Cabera) and Carduoideae, en V. A. Funk, A.

Susanna, T. F. Stuessy & R. Bayer (eds.), Systematics, evo-

lution and biogeography of the Compositae, pp. 193-213.

Vienna: International Association for Plant Taxonomy.

Ribichich, A. M. 2002. El modelo clsico de la togeografa de

Argentina: un anlisis crtico.Interciencia27: 669-675

Ritz, C. M.; L. Martins, R. Mecklenburg, V. Goremykin & F. H.

Hellwig. 2007. The molecular phylogeny ofRebutia(Cacta-

ceae) and its allies demonstrates the inuence of paleogeog-

raphy on the evolution of South American mountain cacti.

American Journal of Botany94: 13211332.

Rodriguez-Cabral, M. A.; M. A. Nuez & A. S. Martnez. 2008.

Quantity versus quality: endemism and protected areas inthe temperate forest of South America.Austral Ecology33:

730-736.

Snchez-Ken, J. G.; L. G. Clark, E. A. Kellogg & E. E. Kay.

2007. Reinstatement and emendation of Subfamily Micrai-

roideae (Poaceae). Systematic Botany32: 71-80.

Simpson, B. B. & C. A. Todzia. 1990. Pattern and processes in

the development of the high Andean ora.American Journal

of Botany77: 1419-1432.

Skeln, P.; E. Dukov & H. Balslev. 2011. Tropical and Tem-

perate: Evolutionary history of Pramo ora. Botanical Re-

view77: 71-108.

Szumik, C.; L. Aagesen, D. Casagranda, V. Arzamendia, D. Bal-

do, L. E. Claps, F. Cuezzo, J. M. Daz Gmez, A. Di Gia-

como, A. Giraudo, P. Goloboff, C. Gramajo, C. Kopuchian,

S. Kretzschmar, M. Lizarralde, A. Molina, M. Mollerach, F.

Navarro, S. Nomdedeu, A. Panizza, V. V. Pereyra, M. Sand-

oval, G. Scrocchi & F. O. Zuloaga. 2012. Detecting areas

of endemism with a taxonomically diverse data set: plants,

mammals, reptiles, amphibians, birds, and insects from Ar-

gentina. Cladistics. 28: 317329.

Szumik, C.; F. Cuezzo, P. A. Goloboff & A. Chalup. 2002. Anoptimality criterion to determine areas of endemism. System-

atic Biology51: 806816.

Szumik, C. & P. A. Goloboff. 2004. Areas of endemism: an im-

proved optimality criterion.Systematic Biology53: 973980.

Szumik, C. & P. A. Goloboff. 2007. NDM/VNDM: Computer

programs to indentify areas of endemism.Biogeografa 2:

32-37.

von Hagen, K. B. & J. W. Kadereit. 2001. The phylogeny of Gen-

tianella (Gentianaceae) and its colonization of the southern

hemisphere as revealed by nuclear and chloroplast DNA se-

quence variation. Organism, Diversity & Evolution1: 61-79.Wieczorek, J.; Q. Guo & R. J. Hijmans. 2004. The point-radius

method for georeferencing locality descriptions and calcu-

lation associated uncertainty.International Journal of Geo-

graphical Information Science18: 745767.

Zhou, J. & K. M. Lau. 1998. Does a monsoon climate exist over

South America?Journal of Climate11: 1020-1040.

Zuloaga, F. O.; O. Morrone & D. Rodrguez. 1999. Anlisis de

la biodiversidad en plantas vasculares de la Argentina.Kurt-

ziana27: 17-167.

Zuloaga, F.O.; O. Morrone and M. J. Belgrano. 2008. Catlo-

go de las Plantas Vasculares del Cono Sur.Monographs in

Systematic Botany from the Missouri Botanical Garden 107:

609967.

APPENDIX 1

NOA (Fig. 4B)The NOA pattern is described in detail in the

discussion. Here we only add that the area is com-posed by three different main patterns. In its widestversion the pattern runs from the limit between Ar-gentina and Bolivia to San Juan supported by fourspecies (see Table 2) the most notably being Ade-smia cytisoidesandJarava media. Several speciesare distributed as shown in the consensus area inFig. 4B e.g.,Panicum chloroleucumandPolygalaargentiniensis, while the third group of species arelacking in the northernmost part of the area, e.g.,Bulnesia schickendantzii, Plectrocarpa rougesii

and Sporobolus maximus.

Yavi-Santa Victoria (Fig. 4K)

The Santa Victoria-Yavi area separates as an indi-vidual area of endemism in the north-eastern cornerof the Jujuy border. The Santa Victoria-Yavi area issupported by 17 endemic species with distributionstightly adjusted to the area, that separates from thegeneral area of endemism at 15% aa, hence the highendemism scores is due to little species overlap be-

tween this area and other distribution patterns ratherthan a high number of endemic species.

Nearly all defining species have been collectedin the surroundings of Yavi in semi-arid Puna oralong the high Andean road between Yavi and San-ta Victoria in sub-humid high Andean, or montanegrassland. We suspect that the Santa Victoria-Yaviarea is artificially delimited both towards the northand south. Botanical collections are incomplete insouthern Bolivia but the eastern slopes of the East-

ern Andes range in Salta area almost unexploredbotanically except for the road leading to Santa Vic-toria.

Jujuy (Fig. 4C)

The core of the area that lies within the Eastern


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Andes range is supported by 67 endemic speciesfrom 48 genera and 23 families (Table 2). The en-demic species are found in a wide range of availablehabitats in semi-desert to humid environments be-

tween 500 - >4500 m asl that includes the tropicalmoist Yungas forest (Sierra Calilegua), mountaingrasslands (Sierra de Calilegua, Sierra de Zenta), aswell as the slopes of the inner dry valleys (Quebra-da de Humahuaca). The few species that are foundexclusively above 3500 m, in this area, are fromwell to sparsely collected high peaks such as MinaAguilar and Nevado de Chai, as well as Nevadodel Castillo and Cerro de Fundicin in Salta.

The Jujuy area is not easily delimited as the coreis surrounded by a diffuse border with a gradual-ly decreasing endemism score (Fig. 4C). The highnumber of sub-sets included in the consensus alsoindicates that the distribution patterns supportingthis area are far from uniform (Table 3). A totalof 35 species are endemic to the border (Table 2)that includes same habitats as the core as well asPuna environment between the Eastern and West-ern Andes range. The main part of the species de-fining the border area are either species found inthe Puna (e.g.,Lobivia einsteinii,Mancoa venturii,

and Senecio punae) or species present along thethe mountain grasslands reaching the Santa Victo-ria area (e.g.,Macropharynx meyeri,Microliabumhumile, andSilene bersieri). Part of the area entersBolivia as four of the defining species have beenfound in the Tarija department (Parodia stuemeri,Psychotria argentinensis,Puya micrantha, and So-lanum calileguae). More of the border species arelikely to appear in the southern Bolivia as botanicalinventories become more complete.

Salta (Fig. 4L)Between the high-endemic Jujuy and Tucumn

areas lies the Salta area that separates from themain consensus under the 50% consensus criterion.A total of 29 species are endemic to the core areamainly found in montane grasslands, and slopes ofthe inner dry Valleys.

Like the Jujuy area, the Salta area has diffuseborders that overlap and shares species with theborder of the Jujuy area and the northern part of

the Tucumn area. The high Andean endemics arerestricted to this part of the area where endemicspecies from Nevado del Castillo and Cerro delCajn also supports the southern Jujuy or northernTucumn area respectively. The high mountainspeaks of the core area such as Cerro Malcante

(5226 m) and Nevados de Palermo (6200m) havenot been explored botanically to our knowledgeand could add new endemics to this area.

Tucumn (Fig. 4D)Like the Jujuy area the Tucumn area lies in the

eastern Andes range and contains mainly the samehabitat types as in the core-Jujuy area. In termsof altitude, temperature, and precipitation, theTucumn area is just as variable as the core area ofJujuy. A total of 62 species are endemic to the areafrom a total of 41 genera and 25 families (Table 2).

The area includes tropical moist Yungas forest(eastern slopes of Sierra del Aconquija and Cum-bres de Tafi), mountain grasslands (Cumbres delTaf, Cumbres Calchaques and Sierra del Aconqui-ja), as well as the slopes of the inner dry Valleys(Valles Calchaques). Species found exclusivelyabove 3500 m asl are mainly from peaks of the twomain ranges (Sierra Aconquija and Cumbres Cal-chaques) or from Cerro del Cajn in the northernextreme of Sierra de los Quilmes.

Unlike the Jujuy area, the Tucumn area haswell defined limits without diffuse border mainlybecause species distribution towards the west can

be defined as an independent area of endemism, seethe Ambato area below.

Jujuy-Tucumn (Fig. 4E)

The combined Jujuy-Tucumn area is definedby species that are found in the cores and/or bor-ders of both the Jujuy and Tucumn areas. The Ju-juy-Tucumn area contains the most complex dis-tribution patterns of the study region, being the leftover of the main consensus area when all sub-ar-eas are extracted at a consensus criterion of 50%.

Like the Jujuy area, the high amount of individualsub-sets that are included in this area indicates thatdistribution patterns supporting this area are notuniform and variations among these are the mainsource of the high number of subsets found in theanalysis in general.

Ambato (Fig. 4M)

West of the Tucumn area and partly overlap-ping with this lies the Ambato area (Fig. 4M) that

is defined by species that reach further south and/or east than the species defining the Tucumn area.The high endemic core of the area incudes 16

endemic species (35% aa) found in semi-desert tosemi-arid environments from 500-3500 m. Thesespecies are mainly found in the montane grasslands


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along the eastern slopes of Sierra Ambato and inhigh Andean habitats of Cerro Manchado.

The border of the Ambato area extends from thecore towards the north and west partly overlapping

with the Beln-Tinogasta area (Fig. 4N).

Beln-Tinogasta (Fig. 4N)

The Beln-Tinogasta area (Fig. 4N) is the west-ern most and least species rich of the three part-ly overlapping areas of Tucumn, Ambato, andBeln-Tinogasta. The area is supported by 12species from rare collections in arid or hyper-aridregions of Sierras de Beln or northern Tinogasta.Only a single species [Tephrocactus geometricus(A. Cast.) Backeb.] have been collected repeatedlywithin the area in Sierras de Beln and Sierra deZapata. The area furthermore includes rare collec-tion of endemic species from the valleys southeastof Cerro Chucula (Tinogasta) and from the easternslopes of Sierra de Fiambal northwest of Beln.

Famatina (Fig. 4H)

Endemism in the Famatina area are mainly fromthe isolated Nevados de Famatina but some species

are also found in the surrounding valleys of Chilci-to and Vinchina as well as Cuesta de Miranda. Thecore of the area is supported by 20 endemic speciesmainly found in semi-desert to semi-arid environ-ments from 1000-4000 m. Twelve of the definingspecies are endemic to Nevados de Famatina withnine species restricted to altitudes at approx. 4000m asl including five species of the ultra high Ande-an Nototrichegenera. The border of the Famatinaareas is composed of a single area mainly definedby four Gymnocalyciumspecies from low altitudes

in valleys north-east of the Nevados de Famatina.

Andes La Rioja-San Juan (Fig. 4F)

Includes high Andes in La Rioja and San Juanand is mainly defined by species found above 3000m in the regions of Laguna Brava (La Rioja) andParque Nacional San Guillermo (San Juan) or col-lected along the few high Andean roads south ofSan Guillermo. Few species from the Andean foot-hill, e.g.,Aphyllocladus ephedroidesand Solanum

glaberrimumalso support the area.San Juan (Fig. 4G)

The southern San Juan area is found outside theAndes range. The area includes valleys and minorpeaks of the Pampeanas Ranges with all defining

species found below 3000 m. Highest altitudes ofthe defining species are found in Sierra Pie de Paloand Sierra del Tontal. The southern San Juan area isone of the driest areas with 50% of the specimens

collected in desert environments.

Inner valleys and Pampeanas Range

The four partly overlapping areas below aredefined by species mainly found in the inner val-leys, slopes and summits of the Sierras Pampeanas.Three of the four areas include species that reachabove 4000 m asl with the lower part of the area setby the altitude of the valley button in the respec-tive areas. Species from the areas are restricted tosemi-desert and semi-arid habitats while few enterdesert environments. Sub-humid locations are onlyreached in these areas at high altitudes with low an-nual mean temperature rather than higher rainfall.

Salta-Catamarca summits and dry inner val-leys (Fig. 4O). The northernmost of the Pampea-nas Range areas are defined by species distributedalong valleys and high Andean locations from San-ta Rosa de Tastil (Quebrada del Toro, Salta) to Sie-

rra Ambato and Quebrada de Beln (Catamarca).

Catamarca-La Rioja summits and dry innervalleys (Fig. 4P). This area includes mainly thelocations Hualfin, Andalgal, Londres, Cuesta deZapata, and Mina Capillitas in Catamarca as wellas Los Corrales in Famatina, La Rioja.

Several species are found in the semi-desert ofthe inner valleys, e.g., the five Cactaceae speciesthat defines the area as well as Sclerophylax cyno-crambefrom the arid radiation of Solanaceae. Thehigh Andean part of the area is defined by speciesdistributed along the summits of the Calchaques,Ambato and Famatina e.g., Poa plicataand Violatriflabellata.

La Rioja-San Juan summits and dry innervalleys (Fig. 4Q obtained under cell size0.5x1.0).The area is mainly defined by speciesdistributed in valleys from southern Catamarca to

San Juan. Several of the endemic species from awide array of families reach desert environmentsin this area, e.g.,Flourensia hirtaand Senecio sa-nagastae (Asteraceae), Lobivia famatimensis andTephrocactus alexanderi(Cactaceae), Senna fabri-sii (Fabaceae), Guindilia cristata (Sapindaceae),


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and Sclerophylax kurtzii (Solanaceae). Only fewspecies in this area reach high Andean environ-ments, e.g., Zephyranthes diluta (Amaryllidaceae)andAdesmia nanolignea (Fabaceae) that are foundalong the high Andes of La Rioja and San Juan.

Valle Frtil (Fig. 4R obtained under cell size0.5x1.0).This minor area of endemism only ap-

pears when using longitudinal cells of 0.5x1.0in which case four species from different familiesdefine the area (Table 2). The main part of the areaconsists of the valley between Sierra de Valle Fr-til/Sierra de La Huerta in San Juan and Sierra deLos Llanos/Sierra de las Minas in La Rioja. Thisarea also reaches the northern part of San Luis,where nearly all defining species have been con-firmed.

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