Two approaches for the selection of Relevant Genetic Units for Conservation in the narrow European endemic steppe plant Boleum asperum (Brassicaceae)

Abstract

Several methods based on population biology, biogeography, ecology, and genetics have been traditionally used for the identification of units for conservation below the species level. We use a combination of two methods based on population genetic structure estimators and on probabilities of loss of rare alleles to identify the Relevant Genetic Units for Conservation (RGUCs). The aims were to assess the genetic diversity and population structure of the endemic steppe plant Boleum asperum (Brassicaceae), and to determine how many and which populations significantly represent the total genetic diversity and the rarest allelic variation. Despite the high amplified fragment length polymorphism genetic diversity values detected in B. asperum (hT = 0.744), caused probably by its hexaploidy and allogamy, moderate spatial genetic differentiation was detected among populations (< 20%) and geographical ranges (> 13%), suggesting the existence of an ancestral continuous distribution range that was fragmented into separate 'islands' in more recent historical times. Five RGUCs, accounting for the 85.10% of the total genetic variation and representative of the entire geographical distribution of the species, were selected for in situ conservation. Ex situ conservation is proposed to complement the preservation of B. asperum. This method of objective selection of populations may be applied to other candidate taxa for conservation with prior adjustment of the threshold values of diversity required for effective protection of each particular species.

The fewer and the better: prioritization of populations for conservation under limited resources, a genetic study with Borderea pyrenaica (Dioscoreaceae) in the Pyrenean National Park

“…G ST values of Gavarnie suggest that the monitoring of five populations would represent the 99.9% of the genetic diversity attributable to most common alleles. This figure exceeds by 9% previous suggestions for the successful accomplishment of conservation goals (Hamrick 1983;Caujapé-Castells and Pedrola-Monfort 2004) but agrees with the values recommended for narrow range endemics (López-Pujol et al 2004;Sánchez et al 2004;Pérez-Collazos et al 2008 variation in the allele frequencies that are shared among most of the populations. Therefore, there is no need to increase this figure by including more populations but to choose five populations among the more genetically diverse ones (Table 1).…”

“…Genetic data can provide information on the levels and structure of genetic variation and can help to identify the population genetic relationships and to suggest the best sampling strategies to preserve adequate and representative levels of genetic diversity with minimum expense (Petit et al 1998;Fraser and Bernatchez 2001;Fay 2003;Orellana et al 2009). In this sense, population genetic studies of Vulnerable taxa are highly recommended to identify minimum relevant genetic units for conservation (RGUCs, Ciofi et al 1999), which should be compatible with the maintenance of the evolutionary potential without interfering with the evolutionary history of the populations (Caujapé-Castells and Pedrola-Monfort 2004; Sánchez et al 2004;Pérez-Collazos et al 2008). This is particularly true for European taxa that inhabit high mountain areas and that have experienced different histories of population size contraction-expansion during the climatic changes of the Quaternary (Hewitt 1996(Hewitt , 2000Taberlet et al 1998;Stehlik 2000;Larena et al 2002Larena et al , 2006) that have conditioned their levels of genetic diversity and the phylogeographical relationships between populations (Vargas 2003).…”

Genetic diversity, genetic structure and phylogeography of the Iberian endemicGypsophila struthium(Caryophyllaceae) as revealed by AFLP and plastid DNA sequences: connecting habitat fragmentation and diversification

“…Not surprisingly, a strong genetic structure was detected at the regional level in populations of Boleum asperum Desv. (Pérez‐Collazos, Segarra‐Moragues & Catalán, ) endemic to northern gypsum outcrops, populations of Krascheninnikovia ceratoides (L.) Gueldenst. (Pérez‐Collazos & Catalán, ) from the Ebro‐Alfambra river basins and populations of Vella pseudocytisus L. subsp.…”

Genetic structure and variability of the endemic and vulnerable Vellozia gigantea (Velloziaceae) associated with the landscape in the Espinhaço Range, in southeastern Brazil: implications for conservation

“…To infer the number of genetic clusters (populations), we calculated the average of each K likelihood value, 'log of probability' (LnP(D)), through all runs as suggested by Pritchard et al (2000) and the statistic DK according to Evanno et al (2005). As done in several other studies (e.g., Pérez-Collazos et al 2008; Segarra-Moragues and Catalán 2010), the F ST value obtained in ARLEQUIN was used to estimate the number of populations needed to represent a given proportion (P) of the genetic diversity according to the modified equation of Ceska et al (1997):…”