Age and Size Structure in Populations of a Long-Lived Dioecious Geophyte: Borderea pyrenaica (Dioscoreaceae)

García, María Begoña Villar; Antor, Ramón J.

doi:10.1086/297246

Cited by 44 publications

(47 citation statements)

References 43 publications

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“…Guitian, 1995;P. Guitian, 1995), though sometimes males may outnumber females (Richards, 1988;Garcia et Antor, 1995;Feil, 1992;Allen et Antos, 1993;Thomas et La Frankie, 1993) or females may outnumber males (Feil, 1992). Furthermore, recent studies have shown that sex ratio within a species or a population may vary in response to environmental factors (Freeman eta/., 1976;Allen et Antos, 1993) or as a function of plant age (Ailiende et Harper, 1989;Escarre et Houssard, 1991;Houssard eta/., 1994;Garcia et An tor, 1995 ).…”

Section: Y Discussionmentioning

confidence: 99%

Reproductive biology ofCorema album(L.) D. Don (Empetraceae) in the northwest Iberian Peninsula

Guitián

Medrano

Rodríguez

1997

Acta Botanica Gallica

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Summary.-We report a study of the reproductive biology of the dioecious shrubCorema album in Galicia (N-W Spain). Male flowers were larger and heavier than female flowers, though the overall investment in sexual reproduction by females was higher. Population pollen-to-ovule ratio was very high (about 173 000:1). Flowering phenology was synchronous between males and females.The relative spatial distribution of the sexes appears to be random. Fruit set was not significantly dependent on either distance to the nearest male or sum of distances to the nearest five males. However, our results suggest that fruit set is higher in population nuclei with high population densities. Furthermore, mean single-fruit weight was higher in the population nucleus with highest fruit set than in the other nuclei studied.Resume.-Nous presentons une etude de Ia biologie reproductive de Corema album, arbuste dio'ique present en Galice (N.-0. de I'Espagne). Les fleurs males sent plus grandes et plus lourdes que les fleurs femelles. Le rapport pollen I ovule dans Ia population est Ires eleva (environ 173 000:1 ). La phenologie de Ia floraison est synchrone entre les plantes males et femelles. La distribution spatiale relative des sexes semble se faire au hasard. Le niveau de fructification ne semble dependre ni de Ia distance a Ia plante male Ia plus proche, ni de Ia somme des distances des cinq plantes males les plus proches. Cependant nos resultats suggerent un niveau de fructification plus eleva dans des noyaux de population ayant des densites de population plus elevees. En outre le poids moyen d'un fruit est superieur dans le noyau de population ayant le niveau de fructification le plus eleva.

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Section: Y Discussionmentioning

confidence: 99%

Reproductive biology ofCorema album(L.) D. Don (Empetraceae) in the northwest Iberian Peninsula

Guitián

Medrano

Rodríguez

1997

Acta Botanica Gallica

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“…The genus Borderea comprises only two extant species [B. pyrenaica Miègeville and B. chouardii (Gaussen) Heslot] restricted to a narrow geographical area in the Central Pyrenees and Prepyrenees (Gaussen 1965;Catalán 2002, 2003). The two Borderea species are orophyte taxa that share several biological attributes related to their dioecy, obligate outcrossing, and perennial long life spans of .300 years (García and Antor 1995;García 2003). However, they are differentiated for several morphological traits (Gaussen 1965;Segarra-Moragues and Catalán 2005a) as well as for their ecology and geographical distribution (Segarra-Moragues and Catalán 2005b).…”

Section: Sampling Of Taxamentioning

confidence: 99%

A Bayesian Approach for Discriminating Among Alternative Inheritance Hypotheses in Plant Polyploids: The Allotetraploid Origin of Genus Borderea (Dioscoreaceae)

et al. 2006

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Polyploidy is a common phenomenon occurring in a vast number of land plants. Investigations of patterns of inheritance and the origins of plants (i.e., autopolyploidy vs. allopolyploidy) usually involve cytogenetic and molecular studies of chromosome pairing, chromosome mapping, and marker segregation analysis through experimental crosses and progeny tests. Such studies are missing for most wild species, for which artificial crosses are difficult, not feasible, or unaffordable. We report here a Bayesian method to discriminate between alternative inheritance patterns in the two extant, tetraploid species of the monocot genus Borderea (Dioscoreaceae), which does not involve progeny array tests. Our approach is based on the screening of a large number of SSR genotypes, which were obtained from successful amplifications of 17 microsatellite regions in individuals of both B. chouardii and B. pyrenaica. We tested for tetrasomic vs. disomic modes of inheritance, using the Bayes factor test. Assignment of genotypes under both alternatives could be unequivocally done for 14 and 11 of the 17 studied microsatellite regions in B. chouardii and B. pyrenaica, respectively, totaling 9502 analyzed genotypes. The comparison of posterior probabilities for the two competing hypotheses across the surveyed loci clearly favored a disomic inheritance pattern. Linkage tests indicated that none of the studied SSR loci were in linkage disequilibrium, thus representing independent samples of the Borderea genome. These results, along with previous allozyme data, support the allotetraploid origin of this paleoendemic genus and reveal the lowest reported chromosome base number for the family of the yams.

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“…Borderea shows one of the longest known life spans for any herbaceous plant (>300 years; see compiled data by Noode´n, 1988), similar to its congener B. pyrenaica and the alpine cushion Silene acaulis (dated both over 300 years, Garcı´a and Antor, 1995;Morris and Doak, 1998, respectively). The few specimens examined of A. pyrenaica and C. calceolus indicated that they might be older than 30 years (possibly older than 100 years for C. calceolus, Kull, 1999).…”

Section: Is There Any Evidence Of Past or Current Declines?mentioning

confidence: 98%

“…The method described for B. pyrenaica (Garcı´a and Antor, 1995) was applied to dead tubers of its congener B. chouardii (n=15 still intact dead tubers after being taken out from crevices). This genus has the unusual feature that the annual aerial stem leaves a scar on the tuber surface, allowing for the estimation of minimum age.…”

Section: Life Spanmentioning

confidence: 99%

An evaluation of the status of five threatened plant species in the Pyrenees

García

Guzmán

Goñi³

2002

Biological Conservation

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In this paper we assess the conservation status of five of the most threatened species in the Pyrenean range (listed in the European Habitats Directive), and present updates of their distribution, reliable censuses to estimate population sizes, population growth rate, population structure, longevity, reproductive success and frequency of herbivory. Recent surveys and careful censuses revealed that the four taxa exclusively restricted to rocky habitats (Borderea chouardii, Androsace pyrenaica, Petrocoptis pseudoviscosa, Petrocoptis montsicciana) have more populations and/or individuals than previously thought. The remaining species, an orchid (Cypripedium calceolus), showed an important decline in population number. So while the rupicolous taxa might be considered naturally rare, the orchid is becoming rare. We failed to find evidence of current poor performance within populations, as recruitment was detected, population growth rate was quite stable in recent years, fruit and seed set was apparently adequate, and herbivory and predation were absent or very low. Additionally, most of the species show a long life span, which might buffer them against demographic and environmental stochasticity in absence of human disturbance. #

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Age and Size Structure in Populations of a Long-Lived Dioecious Geophyte: Borderea pyrenaica (Dioscoreaceae)

Cited by 44 publications

References 43 publications

Reproductive biology ofCorema album(L.) D. Don (Empetraceae) in the northwest Iberian Peninsula

Reproductive biology ofCorema album(L.) D. Don (Empetraceae) in the northwest Iberian Peninsula

A Bayesian Approach for Discriminating Among Alternative Inheritance Hypotheses in Plant Polyploids: The Allotetraploid Origin of Genus Borderea (Dioscoreaceae)

An evaluation of the status of five threatened plant species in the Pyrenees

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