arroyo et al- flora de yerba loca

8/11/2019 Arroyo Et Al- Flora de Yerba Loca

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767Revista Chilena de Historia Natural

75 : 767-792, 2002

Analysis of the contribution and efficiency of the Santuario de laNaturaleza Yerba Loca, 33 S in protecting the regional vascular plant

flora (Metropolitan and Fifth regions of Chile)

Anlisis de la contribucin y eficiencia del Santuario de la Naturaleza Yerba Loca,33 S, en la proteccin de la flora vascular regional (regiones Metropolitana y Quinta

de Chile)

MARY T. K. ARROYO1, CLODOMIRO MARTICORENA2, OSCAR MATTHEI2,

MLICA MUOZ3& PATRICIO PLISCOFF1

1Center for Advanced Studies in Ecology and Research on Biodiversity (CMEB), Facultad de Ciencias,Universidad de Chile, Casilla 653, Santiago, Chile;

e-mail: [email protected] de Botnica, Facultad de Ciencias Naturales y Oceanogrficas, Universidad de

Concepcin, Casilla 160-C, Concepcin, Chile3Seccin Btanica, Museo Nacional de Historia Natural, Casilla 787, Santiago, Chile

ABSTRACT

Santuario de la Naturaleza Yerba Loca (SN Yerba Loca), Metropolitan Region (MR), 33 S, Chile is analyzed for itsconservation value and efficiency in protecting native vascular plants in a regional context. The reserves flora of 500species and subtaxa was evaluated for species richness, endemism, range size and marginally distributed taxa, usingspecies-area analysis, and tendencies in the floras of the MR (1.434 species and subtaxa) and MR-Fifth regions (1,841species and subtaxa) to set the regional pattern. The reserve (0.7 % of MR land area and 0.3 % MR-Fifth land area)contains 34 % of the MR and 27% of the MR-Fifth floras, and around 16-17 % of the mediterranean-climate area(regions IV-VIII) flora of central Chile. Veechs Relative Richness Index (RRI) revealed that SN Yerba Loca houses

exaggerated richness in relation to its land area (28 % more species than expected from the regional model). However,endemism rates (35 % Continental Chile endemics, 22 % Mediterranean endemics, 3% MR-Vth endemics) arestatistically lower than in the MR (44 %, 29 %, 9 %) and the MR-Vth (48 %, 31 %, 11 %) floras, and SN Yerba Locahouses proportionately fewer MR endemics (2 %) than the MR (6 %). Compared with the regional floras, the reservecontains statistically fewer marginally distributed species, and range size (median = five administrative regions) issignificantly larger. The reserves outstanding species richness compensates for its low endemism rates bringing theabsolute number of endemics to 92 % of the regional expectation. Corresponding values for marginally distributedspecies are 81 % (northern limits), 63% (southern limits) and for median and shorter range taxa, 100 %. It is concludedthat SN Yerba Loca is a highly efficient reserve from the point of view of vascular plant conservation, and representsan excellent conservation choice. SN Yerba Loca and MN El Morado (a second state protected area in the MR),conservatively, house 39 % of the native vascular plant flora of the MR (30 % of that of the MR-Fifth) on 0.9 % of MRland area. Our study emphasizes that relatively small land areas in central Chile can house significant amounts ofbiodiversity, and that moreover, the RM and RM-Fifth are areas of high species richness within the central Chileanbiodiversity hotspot. The outstanding conservation value of SN Yerba Loca calls for a management plan designed to

assure the integrity of the reserve under increasing pressures from the Metropolitan Region with six million inhabitants.

Key words:conservation efficiency, endemism, hotspot, protected area, mediterranean flora, species richness, SNYerba Loca.

RESUMEN

Santuario de la Naturaleza Yerba Loca (SN Yerba Loca), 33S, un rea protegida en la Regin Metropolitana (RM) deChile, es analizado en trminos de su aporte a la conservacin de la flora vascular y su eficiencia en un contexto regional.Se analiz la flora vascular nativa, compuesta por 500 taxa en terminos de riqueza de especies, endemismos, rango dedistribucin, y presencia de taxa con lmites de distribucin geogrfica en la zona de estudio, empleando anlisis deespecie-rea y en base de tendencias en las floras de la RM (1-434 especies y subtaxa) y RM-Quinta Regin (1.841especies y subtaxa). La reserva (de 0,7 % de la superficie de RM y 0,3 % de RM-Quinta Regin) contiene el 34 % de

la flora nativa de RM y el 27 % de RM-Quinta Regin, y alrededor de 16-17 % de la flora mediterrnea (regiones IV-VIII) de Chile central. El ndice de Riqueza Relativa (IRR) de Veech indica que SN Yerba Loca alberga una riquezaextraordinaria en relacin a su superficie (28 % ms especies de lo esperado del modelo regional). Sin embargo, losniveles de endemismo para SN Yerba Loca (35 % endmicos de Chile continental, 22 % endmicos de la zona


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768 ARROYO ET AL.

INTRODUCTION

The conservation of biodiversity in a modern

context (Heywood & Watson 1995) spans thegamut from the sustainable use of the componentsof biodiversity to strict preservation. Globally,protected areas are considered to constitute animportant means for protecting biodiversity(Miller et al. 1995). Most national (and someprivate) protected areas combine the sustainableuse of the components of biodiversity andbiodiversity preservation. The protection andmaintenance of biodiversity in the naturalenvi ronment on the one hand, underp insrecreation, while the use of protected areas forrecreation permits biodiversity per se to bepreserved through non-extractive sustainable use.At the landscape level, protected areas also canperform important ecological services, such aswatershed protection, CO

2sequestration (e.g. as

in forests) and maintenance of carbon sinks (e.g.,as in peat bogs).

Although the protection of biodiversity is nowexplicitly recognized as an objective of protectedareas, many protected areas were set up prior toworld concern about biodiversity, with scenic or

wilderness value, or the protection of a selectnumber of useful or charismatic species being theoverriding cri teria for their es tabl ishment(Armesto et al. 1998). For example, in India,protected areas of forest species have existedsince the IV century (Groombridge 1992). Usingdata given in Groombridge (1992), around 60 %of all existing protected areas were establishedbefore the 1980s, which corresponds with thedecade of accelara ted g lobal concern forbiodiversity. It was in the late 80s that Wilson &Peters (1988) brought the notion of biodiversity

to a wide field of scientists and others. Thecont racted form of b io logical d ivers i ty(biodiversity) was apparently coined by WalterG. Rosen in 1985 for the first planning mee ting of

mediterrnea y 3 % endmicos a RM-Quinta Regin) son estadsticamente ms bajos que los niveles regionales (RM:44, 29 y 9 %; RM-Quinta Regin: 48, 31, y 11 %), y SN Yerba Loca alberga proporcionalmente menos taxas endemicosa RM (2 %) que RM (6 %). En comparasin con las floras regionales, SN Yerba Loca contiene menos especiesmarginalmente distribuidas, y los rangos geogrficos para especies presentes en SN Yerba Loca (mediana = cinco regionesadministrativas) son significativamente mayores que en las floras regionales. La riqueza destacada de la reserva compensasu bajo nivel de endemismos, con el nmero absoluto de taxas endemicos llegando al 92 % de la expectacin regional.Valores correspondientes para especies con distribuciones marginales son 81 % (lmites norte), 63 % (lmites sur) y para

taxas con rangos cortas, 100 %. Se concluye que SN Yerba Loca es una reserva muy eficiente desde el punto de vista deconservacin de la flora vascular. SN Yerba Loca y MN El Morado (un segundo rea protegida en RM) constituyen el 0,9% de la superficie de RM. Albergan alrededor del 39 % de la flora de la RM (y 30 % de la flora de RM y RM-Quinta Regin).Nuestro estudio indica que reas pequeas en Chile central pueden albergar mucha biodiversidad, y que RM y RM-QuintaRegin son reas de alta riqueza de especies dentro del hotspot Chile central de biodiversidad. El sobresaliente valor deSN Yerba Loca en lo respecto a la conservacin exige un plan de manejo para asegurar la integridad de la reserva frentede presiones de la Regin Metropolitana con seis millones de inhabitantes.

Palabras clave:eficiencia de conservacin, endemismos, rea protegida,hotspot flora , mediterrnea, riqueza deespecies, SN Yerba Loca.

the National Forum on Biodiversity held inWashington DC in September, 1986 (Heywood &Watson 1995). Gathering concern throughout the

late 80s and early 90s eventually lead to thesigning of the Convention on Biological Diversitywhich came into force in 1993. In Chile the esta-blishment of protected areas dates to 1907, withthe creation of the Reserva Nacional Malleco,followed by the Villarrica, Alto Bo-Bo andLlanquihue forest reserves created in 1912 (Benoit1996). The first national park (still in existence),Parque Nacional Vicente Prez Rosales, wascreated in 1926, with 10 new parks establishedbetween 1935-1945. Over the period 1945-1969,52 additional national parks and forest reservescame into being. Of the 90-odd current protec tedareas in Chile, thus a very large number werecreated before 1980.

As biodiversity became a global concern, thenotion of biodiversity conservation began to makeits way into the hands of the decision makers(e.g., Muoz et al. 1996). However, even today,new protected areas tend to be created more onthe basis of a select group of species, or dominantspecies, rather than concern for adequate andefficient coverage of all species in a region. The

early establishment of many protected areas onthe basis of wild, scenic or utilitarian value,signifies that there can be no guarantee that a setof existing national parks and reserves protectsall of a regions biodiversity. Nor can it be assumedthat existing protected areas are efficient in termsof the amounts of biodiversity they protect. Giventhe latter, as a working hypothesis, individualprotected areas should span the natural range ofvariation in the landscape, there being reserveswith relatively low to relatively high levels ofbiodiversity: that is, some protected areas, by

chance could house high levels of biodiversity,while others could contain low amounts.

In order to consolidate any national protectedarea system a first objective should be that of


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769CONTRIBUTION AND EFFICIENCY OF THE SANTUARIO DE LA NATURALEZA YERBA LOCA

learning how much biodiversity is contained inexisting protected areas. This information is fun-damental for determining which species in theregion of interest are protected and their level ofprotection. Secondly, individual protected areasshould be evaluated for their relative conservation

efficiency. This kind of information is essentialto guide the right decisions when changes in theboundaries (reductions, amplifications) of existingprotecting areas are contemplated. In this paperwe outline and analyze the vascular plant flora ofthe Santuario de la Naturaleza Yerba Loca,Metropolitan Region, 33 S, Chile. The Santuariode la Naturaleza Yerba Loca is one of fourprotected areas managed by CONAF-Chile in thedensely populated Metropolitan Region of Chile.Some 25 % of the land area of the MetropolitanRegion is intensively used for agriculture and

urban development; many semi-natural areas aretoday heavily subject to grazing (Arroyo et al.2000). The Metropolitan Region occurs in themediterranean-type climate area of central Chile(di Castri & Hajek 1976), known for its highlevels of endemism and species richness (Arroyo& Cavieres 1997, Arroyo et al. 1999). Ref lectingthe latter, in a recent paper in Nature, centralChile (based on the original data provided byArroyo et al. 1999 in Mittermeier et al. 1999) hasbeen declared a biodiversi ty hotspot forconservation priority (Myers et al. 2000). Basedon comprehensive floristic lists of the native flo-ra for the Metropolitan Region and Metropolitanand Vth regions combined, we first determine theproportion of the regional floras contained in theSantuario de la Naturaleza Yerba Loca. We thenemploy a series of criteria designed to evaluatethe conservation value of the reserve. Specificallywe analyze the reserves flora from the perspectiveof: (i) total number of vascular plants protected inrelation to the physical size of the reserve; (ii)concentration and absolute numbers of endemic

taxa; (iii) average range size of taxa; (iv) presenceof marginally distributed species. For the purposesof our analysis, a highly efficient reserve is one inwhich: (i) a higher number of species in relationto the expected regional average for the reservesize are protected; (ii) the density of endemicspecies is high; (iii) the average range size ofspecies is low, and (iv) marginally distributedspecies are well represented. Finally, we combinepublished floristic information for MonumentoNacional El Morado (a second protected area inthe Metropolitan Region) with that for Santuario

de la Naturaleza Yerba Loca and determine theproportion of the Metropolitan Region (andMetropolitan-Quinta Region combined) floracontained in the two protected areas.

MATERIAL AND METHODS

Study site

Santuario de la Naturaleza Yerba Loca (hereafterSN Yerba Loca) (Fig. 1) is located in the

Municipality of Lo Barnechea to the NE of thecity of Santiago. The area was decreed a NatureSanctuary on 24 July, 1973 by the ChileanCouncil of National Monuments (Consejo Nacio-nal de Monumentos Nacionales). As originallydesignated, the reserve covers 39,029 ha.However, only the 10,500 ha. of the reservemanaged by the Corporacin Nacional Forestal(CONAF) is considered here. The reserve iscentered on the deeply-cut, northeast-southwesttrending valleys of the Estero Yerba Loca runningfrom the base of Cerro La Paloma, and Estero La

Leonera, situated to the east and running intoEs tero Yerba Loca. I t compri ses s teepmountainous territory located to the east of theRo San Francisco, from its junction with EsteroYerba Loca to the level of La Ermita. EsteroYerba Loca shows strong signs of heavilyglaciation in the Pleistocene. Permanent glaciersare found today on Cerro La Paloma and CerroPlomo. The reserve spans an altitudinal range ofapproximately 1,300 to 5,340 m. However, above3,600 m vascular plants are essentially absent.Vegetation types include typical low-elevationmediterranean sclerophyllous scrub and succulentscrub (900-1,500 m), montane sclerophyllouswoodland dominated by Kageneckia angustifolia(1,600-2,000 m), and high alpine vegetation(2,000-3,600 m). A significant extension ofAndean wetlands (locally referred to as vegas)is found on the eastern side of the reserve belowCerro La Parva. The upper reaches of EsteroYerba Loca below Cerro La Paloma contain oneof the largest and best conserved extensions ofhigh Andean cushion bog in the general area. The

structure and ecology of the alpine vegetation ofthe FarellonesLa Parva-Valle Nevado areaimmediately to the east, as described in Ar royo etal. (1981, 1982) and Cavieres et al. (2000), istypical of SN Yerba Loca. Details on thecompos i t ion and ecology of montanesclerophyllous forest in the reserve can be foundin Arroyo & Uslar (1993) and Pealoza et al.(2001).

Floristic data

Knowledge of the flora of SN Yerba Loca wasgenerated from an intensive field collectingprogram supplemented with a small number of


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previous literature and herbarium records (3 %taxa). Field work incompassed 92 man/womandays of collecting time spread across 31 separatecollecting trips in the early spring to late autumnof 1998-2001 and covered the entire elevationrange of vascular plants, all major watersheds,

ranges and expositions as well as vegetation typesin the reserve. All plant species occurring alongthe explored gradients and trajectories werecollected and herbarium specimens prepared. Eachplant collection was formally recorded in relationto georeferenced points (Garnmin GPS). So as todocument the flora of the reserve, herbariumcollections have been deposited at the Univer sity

of Concepcin (CONC) and Museo National deHistoria Natural (SGO). The field effort resultedin more than 1,700 herbarium collections andtheir respective duplicates. The floristic lists forthe Metropolitan Region and Metropolitan-Fifthregions combined were generated from the Chilean

flora data base, University of Concepcin (version23 August, 2001). This constantly up-datedelectronic data base contains distributional dataat the level of Chile administrative regions andlife-form data for all currently accepted species,subspecies and varieties in the Chilean flora. Theonly major modification to the data base affectedwas replacement of the existing set of names for

Fig. 1:Location of the Santuario de la Naturaleza Yerba Loca, Chile.Ubicacin del Santuario de la Naturaleza Yerba Loca, Chile.

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the genus Calceolariawith a much reduced set oftaxa recognized in the recent taxonomic revisionof the genus by Ehrhart (2000). A few new taxafor the Metropolitan Region discovered in SNYerba Loca were added to the regional lists. Theregional lists can be considered fairly complete,

since the Metropolitan and Vth regions are amongthe best explored in Chile.

Conservation criteria: species richness

In order to evaluate the species packing efficiencyof a reserve, a measure of relative species richnessis required that takes into account that speciesrichness does not increase linearly with size ofarea. The efficiency of SN Yerba Loca inconcentrating species richness was evaluated by

comparing the number of species contained in thereserve in relation to the expected number ofspecies for the reserve land area as predicted froma regional species-area curve. Previous work fora wider area of central Chile (mediterranean areain general) showed that species richness is stronglylinearly correlated with area under the powerfunction (Arroyo et al. 1995, Cowling et al. 1996).In order to evaluate the species richness capacityof SN Yerba Loca, we constructed a new species-area curve for the area comprising the Fifth andMetropolitan regions. The data used to constructthe new curve comprised: (a) current estimates ofspecies richness for the Fifth and MetropolitanRegions obtained from the Chilean species database (see above); (b) species numbers for theValparaso area, Marga Marga Valley, SantiagoValley and Quebrada de La Plata as in Arroyo etal. (1995); (c) a published species list for Monu-mento Nacional El Morado (hereafter MN ElMorado) (Teillier et al. 1994) and the new data

for SN Yerba Loca, as presented herein. Inclusionof MN El Morado also allowed comparison of thespecies packing efficiency of SN Yerba Locawith that of a second protected area in theMetropolitan Region. For the species richnessanalysis, subtaxa were eliminated from the data

sets for the Vth, Metropolitan Region, SN YerbaLoca and MN El Morado, so as to enable use ofthe floristic lists previously published in Arroyoet al. (1995) which correspond to species-levelcounts. Following Veech (2000), we calculatedthe Relative Richness Index (RRI) as per Bowers& McLaughlin (1982) for all data points used inconstructing the regression line. RRI is obtainedfrom the regression residuals expressed as apercentage of the expected number of species forthe size of the land area of a reserve (c.f., Bowers& McLaughlin 1982, Veech 2000):

Sobs

-Sexp

RRI = x 100

Sexp

where Sobs

is observed species richness Sexp

isexpected species richness.

Conservation criteria: endemism

The efficiency of SN Yerba Loca in concentratingendemic taxa was evaluated by comparing levelsof endemism in the reserve with those in the florasof the Metropolitan-Fifth regions combined andthe Metropolitan Region. Four endemism categorieswere considered: (a) taxa restricted in distributionto continental Chile; (b) taxa restricted indistribution to administrative regions Fourththrough Eigth; (b) taxa restricted in distribution tothe Metropolitan and Vth regions combined; (c)

TABLE 1

Comparison of species richness (species and subtaxa) and life-form composition for the nativevascular plant floras of the SN Yerba Loca, Metropolitan Region, 33 S, the Metropolitan and

Fifth regions combined, and the Metropolitan Region, Chile

Comparacin de la riqueza de especies (especies y subtaxa) y composicin en trminos de forma de vida de lasfloras vasculares nativas del SN Yerba Loca, Regin Metropolitana, 33 S, regiones Metropolitana y Quinta

combinadas, y la Regin Metropolitana, Chile

SN Yerba Loca Metropolitan Metropolitan-FifthLife-form n % n % n %

Annual and biennials 105 21.0 301 21.0 361 19.6Perennial herbs 278 55.6 801 55.8 1,038 56.4Shrubs and subshrubs 109 21.8 295 20.6 394 21.4Trees 8 1.6 37 2.6 48 2.6Total native flora 500 1,434 1,841

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taxa restricted in distribution to the MetropolitanRegion. Taxa (species, or subtaxa) restricted indistribution to continental Chile will be referred toas Continental Chile endemics. Taxa restrictedin distribution to Chile and the area described byadministrative regions IV-VIII will be referred to

as Mediterranean endemics. These lastadministrative regions were chosen as a surrogatefor the mediterranean-type climate region basedon their close fit to the latitudinal limits of themediterranean-climate area as defined by VanHusen (1967) (30-38 S) and the availability ofaccurate species lists at the level of Chilesadministrative regions in the Chilean flora database (University of Concepcin). It should be notedthat taxa endemic to the Metropolitan Regionconstitute a subset of the Metropolitan-Vth regionscombined endemics, which in turn are a subset of

the Mediterranean endemics. Mediterraneanendemics comprise a subset of the Continental Chileendemics. Endemism status at the level of continen-tal Chile was determined by consulting thegeographical distributions of species in monographictreatments, and checking the recently publishedchecklists for neighboring or geographically-closeArgentina (Zuloaga et al. 1994, Zuloaga & Morrone1996, 1999), Peru (Brako & Zarucchi 1993) andEcuador (Jorgensen & Len-Yez 1999). Subsetsof mediterranean and regional endemics wereobtained by filtering distributional informationcontained in the Chilean flora data base at the levelof Chiles administrative regions. Statisticalcomparisons of endemism levels for SN Yerba Locawith the regional floras were made using the G-testof independence (Sokal & Rohlf 1995).

Conservation criteria: range size

In order to determine whether the constituent taxain the SN Yerba Loca reserve are more narrowly

distributed on average than species in the regio-nal floras, we compared the range sizes of speciesand their subtaxa in the SN Yerba Loca, theMetropolitan-Fifth regions combined and theMet ropol i t an Region . The number of administrative regions occupied by each taxa inChile was used as an index of range size. FollowingMatthei (1995) and Arroyo et al. (2000), the Vthand Metropolitan Regions were amalgamated intoone composite region. The latter was consideredappropriate so as to define a geographical unitthat i s more equivalent to the o ther 11

administrative regions in Chile, all of which spanthe breath of Chile from the Pacific Ocean to theAndean cres t . Range s ize was calcu la tedseparately for the subsets of Continental Chile

endemics, Mediterranean endemics and non-endemic native taxa. The subset of Metropolitan-Fifth regions combined and Metropolitan Regionendemics were not considered in this analysis, inthat all species on the criteria used here, have thesame distributional ranges (one administrative

region). Use of the number of administrativeregions gives an approximate measure of rangesize, in that there is considerable variation in thesize of the individual administrative regions inChile. However, when comparisons are made forsubset s of f lora f rom the same generalgeographical area, as is the case here, this variationis of little relevance, in that species in the areascompared are drawn from the same regionalspecies pool, and thus will be subject to the samelevel of error. The number of administrativeregions occupied by a species in Chile is useful as

a comparative measure of geographical range inthe absence of more accurate distributional data,in that it provides a rough measure of the latitudi-nal range. Statistical comparisons of range sizeamong the floras were made using the non-parametric Mann-Whitney U-test (StatisticaVersion 6.0, 1998 version).

Conservation criteria: marginally distributed

species

We evaluated SN Yerba Locas contribution toconserving marginally distributed species byconsidering presence in the reserve of specieswith northern and southern distributional limitsfound within the Metropolitan-Fifth regionscombined, following the same criterion as usedfor range size for determining distributional limits.The percentages of marginally-distributed speciesin SN Yerba Loca were then compared withcorresponding sets of data generated for the re-gional floras using the G-test of Independence

(Sokal & Rohlf 1995). Subsets of species ofdifferent origins (endemic, non-endemic, etc.), aswell as the entire native flora, were considered soas to detect d i f ferences between f lor i s t i ccomponents.

Conservation criteria: combined criteria

Proportional values provide a measure of thepropensity of a local flora to conta in species of agiven category (for example endemic species).

However, low proportional values for any givencategory of species, could be compensated byhigher than average species richness. Absoluteexpected numbers of endemic species, numbers

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Life-form composition in both regional florasis diverse (Table 1) and not significantly different(G = 0.532, NS). The life-form spectra of the SNYerba Loca flora does not differ statistically fromthat of either regional flora (Metropolitan-Fifthregions: G = 1.140, P < 0.05; Metropolitan Region:

G = 0.968, P < 0.05). This indicates that thereserves flora is highly representative of theregional life-form spectrum.

Figure 2 depicts the regional species-arearelationship. The log-log regression is highlysignificant (F

1, 7= 99.781, P < 0.001, R2= 0.934),

indicating that the curve can be used reliably asan indicator of the relationship between speciesrichness and area. Table 2 gives values of theRelative Richness Index (RRI) for areas used inthe analysis, ranked from high positive to lownegative values. It can be seen that RRI for SN

Yerba Loca ranks highest among all the areascompared, the reserve having an excess of 28 %species in relation to the model. On a regionalscale, thus SN Yerba Loca supports outstandingspecies richness in relation to its land area. Ofspecial note is the RRI value for MN Nacional ElMorado. This reserve situated in the Andes in theCajn de Maipo to the south of SN Yerba Loca, incontrast to SN Yerba Loca, is associated with alarge negative RRI value, and thus is an area oflow species richness for its particular land area.Other interesting asides are the higher intrinsicrichness of the Metropolitan Region in comparison

with the Fifth Region, and the very low intrinsicrichness of the Santiago valley.

Endemism

Table 3 provides endemism levels for SN YerbaLoca and the regional floras. So as not tooverestimate endemism levels, the 9 taxa oftentative identity have been placed in the non-endemic category (see Appendix 1). Endemismlevels in the regional floras are high (44-48 %,cont inenta l Chi le endemics ; 2931 %,Mediterranean endemics). Moreover significantnumbers of species are strictly endemic to theregions under consideration (see Table 3). Conti-nental Chile endemism levels are higher in theMetropolitan-Fifth regions combined than in the

Metropolitan Region (G = 5.832, P < 0.05),however this pattern did not characterize the otherendemism categories.

Of the 883 continental Chile endemics in theMetropolitan-Fifth regions combined, 173 (19.6%) are found in SN Yerba Loca. Of the 575Mediterranean endemics found there, 110 (19.1%) occur in SN Yerba Loca. Sixteen of the 193species endemic to the Metropolitan-Fifth regionscombined (8.3 %) are found in the reserve.Corresponding f igures in re la t ion to theMetropolitan Region flora are 27.6 %, 26.1 %,and 12.1 % respectively. The reserve contains 11

TABLE 2

Values of the Relative Richness Index (RRI) for different areas in the Fifth and Metropolitanregions, central Chile, including the SN Yerba Loca and MN El Morado, based on the

regression equation in Fig. 2. Data correspond to species numbers, disregarding subtaxa. Highpositive values of RRI indicate exaggerated species richness in relation to land area. Low

negative values indicate low average richness in relation to land area

Valores del ndice de Riqueza Relativa (RRI) para diferentes reas en las regiones Quinta y Metropolitana, Chile

central, incluyendo el Santuario de la Naturaleza Yerba Loca y MN El Morado, basado en la ecuacin de regresinen la Fig. 2. Los datos corresponden a riqueza de especies, sin contabilizar los subtaxa. Valores positivos altos deRRI indican reas con una riqueza intrnseca exagerada con relacin al rea. Valores grandes negativos indican una

riqueza muy baja con relacin al rea

Area Species Land area (km2)* Expected S RRI

SN Yerba Loca 488 105 382 27.7Fifth-Metropolitan regions 1,723 31,538 1,452 18.7Quebrada de La Plata 249 10 220 13.2Metropolitan Region 1,355 15,507 1,229 10.3Fifth Region 1,276 16,031 1,231 3.0Valparaso area 799 3,300 856 -6.7

MN El Morado 245 30 285 -14.0Marga Marga valley 457 450 537 -14.9Santiago valley 654 4,000 895 -26.9

*Land area for the Fifth and Metropolitan regions as in CONAF-CONAMA-BIRF (1999)

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of the 91 (12.1 %) strictly Metropolitan Regionendemics. Although high proportions of theendemic taxa found in the regional floras occur inSN Yerba Loca, the reserves endemism levelsare significantly lower than in the two regionalfloras: (a) Metropolitan-Fifth regions: continen-tal Chile endemics: G = 28.800, P < 0.001;

Mediterranean endemics: G = 16.883, P < 0.001;Metropolitan-Fifth endemics: G = 31.425, P

arroyo et al- flora de yerba loca

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