Biologia 64/2: 271—278, 2009 Section Botany DOI: 10.2478/s11756-009-0033-7 Reproductive success and variation in floral traits in the Iberian Peninsula endemic white campion Silene marizii (Caryophyllaceae) Mónica García-Barriuso1,EvaM.Ávila1,M.AngelesSánchez-Anta1, Antonio L. Crespí2,SoniaBernardos1 &FranciscoAmich1 1Evolution, Taxonomy and Conservation Group (ECOMED), Department of Botany, University of Salamanca, E-37008 Salamanca, Spain; e-mail: [email protected] 2Herbarium/Botanic Garden, Environment and Life Technological Studies Center (CETAV), University of Trás-os-Montes eAltoDouro,P-5001-911 Vila Real, Portugal Abstract: Silene marizii (Caryophyllaceae) is a schizoendemism of the west Iberian Peninsula. The correlation between the evolution of reproductive success (as measured in terms of fruit set and seed production) and five floral traits (peduncle length, calyx length, calyx width, petal limb length, and petal limb width) was investigated in five populations of S. marizii, taking into account both intra-populational and inter-populational variability. The populations studied represented the different habitats of S. marizii over its area of distribution. None of the five traits examined was significantly and positively correlated with the number of seeds produced by the flower. An analysis was also made of how floral morphology varies with the position of the flower in the inflorescence in the five populations. The populations from higher altitudes (Caramulhino, Puerto de Menga and Pe˜na de la Cruz) had larger peduncles, calices and petal limbs than those living at lower altitudes (Sabugal and Mangualde) All five morphometric traits, plus the number of ovules per ovary, varied significantly between flower positions on the same plant and among populations. Key words: Silene marizii; Dioecius; floral morphology; ovule number; phenotypic variability; reproductive success; Por- tugal; Spain Introduction patterns of variability found can be interpreted within the set of selective pressures that pollinators exert. Given the strong association between the evolution of One of the most common ways of measuring re- entomophilous plants and their pollinators, it is rea- productive success in angiosperms is fruit set (Zimmer- sonable to suppose that variation in floral morphology man & Aide 1989; Proctor & Harde 1994). Over the should be reflected by variation in individual repro- last few decades, different authors have followed vari- ductive success, which might lead to evolutionary di- ous approaches to study the variation in floral morphol- vergence and speciation. Variable morphological traits ogy and its effect on reproductive success (Schlichting that have no effect on reproductive success are un- 1986; Herrera 1990; 1993; Wolfe 1993; Johnson et al. likely to lead to evolutionary change (Herrera 1990). 1995; Diggle 1995; García-Cruz & Sosa 2007). In many plant species, the size and number of repro- In this work we investigated within-population ductive structures and the components of female re- variation in a number of floral characters of Silene ma- productive success show marked among-flower within- rizii Samp., an endemic of the western Iberian Penin- inflorescence variation (e.g. Ashman & Hitchens 2000). sula. We also assessed the variability of the charac- Floral variation may occur at several hierarchical levels ters among populations and among flowers at different (e.g. Williams & Conner 2001) including among flowers positions in the inflorescence. Studies of this type on within plants, among individuals that live in the same plants such as S. marizii (Guitián et al. 1997) are of site, or among plants in different populations. The rela- particular interest because they address the immediate tive contribution of individuals and populations to over- practical concerns of species conservation, and because all variability has evolutionary implications and can they may contribute to a better understanding of the give an insight on how inclined to local differentiation phenomenon of endemism (Kruckeberg & Rabinowitz is that particular plant species. 1985). The intraspecific variability of rare species (sensu Most of the studies that have evaluated reproduc- Rabinowitz 1981) has immediate evolutionary implica- tive success in angiosperms have included information tions (Primack 1980; Stebbins 1980). The study of flo- for only one or two species, in a reduced geographic ral characteristics of potential importance in the plant- area, and have only evaluated one o two floral traits pollinator relationship offers the advantage that the (García-Cruz & Sosa 2007). In the present study, five c 2009 Institute of Botany, Slovak Academy of Sciences 272 M. García-Barriuso et al. Fig. 1. Populations studied of Silene marizii in the Iberian Peninsula. morphological traits of this endemism of the western Silene marizii belongs to the section Elisanthe (Fenzl) Iberian Peninsula were studied in populations repre- Fenzl. It is a perennial herb, (15)20–60(70) cm high, densely senting its entire Iberian distribution. glandular and fetid, and has a pauciflorate dichasium. The The aims of this work, the first to be undertaken female flowers have a hardly noticeable carpophorus, much on the reproductive biology and ecology of this Iberian shorter than the capsule. Pollination is by insects, bee endemic member of the Caryophyllaceae, were: 1) to in- flies (Bombyliidae: Bombyliflorus fuliginosus), were cap- tured during the present fieldwork. Flowering starts in vestigate the variation of five floral morphological traits (April)-May and finishes at the beginning of July. Silene among flowers at different positions in the inflorescence, marizii, described by Sampaio (1909) from Mangualde and within populations, and among populations, and 2) to Serra do Caramulo (Portugal: Beira Alta Province), is en- determine whether these traits are related to reproduc- demic of the central western Spain and north-western Por- tive success, measured in terms of fruit set and seed tugal (Prentice 1977; Talavera 1990), where it occurs in a numbers. few populations. The species appears in the 2000 and 2007 issues of the Spanish Red List of Vascular Plants (Listas Ro- jas de la Flora Vascular Espa˜nola) (VV.AA. 2000, Moreno Material and methods 2008) under the categories ‘Vulnerable’ (VU: B1 + 2b, D2) and “Critically Endangered” (CR: B2ab(ii,iii,iv,v)c(iv)) re- Study system and field sites spectively. Change of category is due to a continuing decline The nomenclature used and the boundaries of the species of area of occupancy, numbers of locations and mature in- recognised were those employed by Talavera (1990). The dividuals, and extreme fluctuations of number of mature syntaxonomic nomenclature followed was that suggested by Rivas-Martínez et al. (2001, 2002). The five study sites that individuals. were home to S. marizii belonged to the following phyto- Historical records of Silene marizii in the Iberian geographical units described by Rivas-Martínez (2005): Peninsula have been documented on the basis of a review Eurosiberian Region, Atlantic European Province, of the specialised scientific literature, and consulted docu- Galaico-Portugués sector (Montemouro-Caramulo District, mentation in several herbaria (BRESA, Technical Institute population 2 and 3). of Bragan¸ca, Portugal; COI, University of Coimbra, Portu- Mediterranean Region, Mediterranean West Iberian gal; HVR, University of Trás-os-Montes e Alto Douro, Vila Province, Estrellense Sector (Guardense District, popula- Real, Portugal; LISI, Instituto Superior de Agronomía, Lis- tion 1), Bejarano-Gredense Sector (Bejarano and Paramero- boa, Portugal; LISE, Esta¸cao Agronómica Nacional, Oeiras, Abulense Districts, populations 4 and 5, respectively). Portugal; LISU, Museu Nacional de História Natural; MA, Dioecy has been correlated with different ecological fac- Royal Botanic Garden of Madrid, Spain; MAF, Faculty of tors (Bawa 1980; Renner & Ricklefs 1995), suggesting that Pharmacy, University Complutense of Madrid; PO, Univer- these have favoured the evolution of dimorphism (Weller sity of Porto, Portugal; SALA, University of Salamanca, et al. 1995). However, in the genus Silene this seems un- Spain); abbreviations follow Holmgren et al. 1990 and Holm- likely since very similar ecological factors have been respon- gren & Holmgren 1993), where possible with direct exami- sible for the evolution of dioecy in all three sections of the nation. All sites with reports of S. marizii populations were genus (Desfeux et al. 1996). In any event, further studies visited to check for the presence of this species, as well a are needed to determine the influence of ecological factors number of other sites at which it might potentially occur. in the evolution of dioecy in Silene. When the species was detected, we recorded geographical lo- Reproduction and variation in floral traits in edemic Silene marizii 273 Table 1. List of populations and number of plants of Silene marizii used for morphometric analyses. Taxa/ Localities UTM coordinates Altitude Temperature Precipitation N◦ individuals Date of N◦ population (m) ( ◦C) (mm) sampling Silene marizii Population 1 PO: Beira Alta, Guarda, 29TPE5671 835 10.5 1195 22 25.5.2007 Sabugal Population 2 PO: Beira Alta, Mangualde 29TPE0696 605 No data No data 24 28.5.2006 Population 3 PO: Beira Alta, Caramulo 29TNE6788 1045 12.3 2166 33 1.6.2006 Population 4 SPA: Salamanca, Béjar 30TTK6372 1410 No data No data 35 3.6.2006 Population 5 SPA: Ávila, Sierra de la 30TUK3084 1475 9.6 1344 24 1.6.2007 Paramera, Puerto de Menga Total: 138