Population clustering and clonal structure evidence the relict state of Ulmus minor Mill. in the Balearic Islands

Abstract

Field elm (Ulmus minor) is a riparian tree that grows in rare, small populations scattered along temporary watercourses in the Balearic Islands, nowadays mostly covered with Mediterranean vegetation. Agriculture and farming on the fertile land along the periodically flooded plains have reduced the elm populations to sparse tree lines along the creek beds. The presence of field elm in this very anthropic landscape has led some authors to consider it as an introduced species in the Balearics. However, pollen data suggest these elms may be the remains of larger populations experiencing continuous population shrinkage during the Holocene, and hence be native to the isles. In this paper, we apply genetic markers to assess whether field elm is or is not indigenous to the Balearic Islands. We compare the genetic variation in nine nuclear microsatellites of six Balearic populations (three in each of the largest islands, Majorca and Minorca) with that of three natural Iberian populations located in two regions, one geologically (Baetic mountains, SE Iberia) and another historically (Catalonia, NE Iberia) related to the islands. Principal coordinates analysis and Bayesian clustering methods reveal a strong genetic differentiation of the Balearic populations from the Iberian ones, and even among islands, which support their native origin. Genotypic variation in the islands is very low and clonal reproduction is very high compared with the mainland, as it is frequently observed in populations of clonal species where sexual reproduction is limited. We discuss the practical implications of these findings for the conservation of elm genetic resources of these findings.

Alive and kicking, or, living on borrowed time? – Microsatellite diversity in natural populations of the endangered Ulmus minor Mill. sensu latissimo from Croatia

“…The presented results are congruent with those obtained by studies of allozymes (Machon et al 1997), isozymes (Machon et al 1995, Cogolludo et al 2000, RAPDs and ISSRs (Coleman et al 2000, Goodall-Copestake et al 2005 and SSRs (Fuentes-Utrilla et al 2014). Although studies of the fi eld elm on the European level suggest a high degree of intrapopulation genetic diversity, they also suggest conclusions concerning the small genetic differentiation between populations belonging to different geographic regions.…”

“…Microsatellites found their application in the resolving of the taxonomic status of U. procera Salisb. ) and recently in assessing whether the fi eld elm is or is not indigenous to the Balearic Islands (Fuentes-Utrilla et al 2014).…”

New resources for genetic studies in Populus nigra: genome‐wide SNP discovery and development of a 12k Infinium array

“…These results are comparable to earlier published data (Storme et al 2004;Smulders et al 2008;Chenault et al 2011) suggesting that in nature P. nigra is highly clonal along long tracts of riparian river basins that may stretch for several kilometres. As for other temperate, riparian species (Populus spp., Salix ssp., Ulmus ssp; Stueffer et al 2002;Santos-del-Blanco et al 2013;Lin et al 2009;Fuentes-Utrilla et al 2014), the rate of clonality observed could enable persistence of local populations under unfavourable conditions (Storme et al 2004;Smulders et al 2008;Chenault et al 2011). ADMIXTURE analysis agreed with the PCA results indicating a high level of admixture and low level of genetic differentiation between populations.…”

“…; Fuentes‐Utrilla et al . ), the rate of clonality observed could enable persistence of local populations under unfavourable conditions (Storme et al . ; Smulders et al .…”

Genetic Diversity in Relict and Fragmented Populations of Ulmus glabra Hudson in the Central System of the Iberian Peninsula

“…Many U. laevis populations located along Europe have been studied using these markers [17,29,30]. Genetic diversity of a few localized natural populations of U. minor (e.g., in Balearic Islands, [31]; in the Netherlands, [32]; in Croatia, [33]) and U. glabra (e.g., in Denmark, [34]) have also been studied using microsatellite markers. The most extensive analysis of European populations of these two species together, using restriction fragment-length polymorphisms in chloroplast DNA, AFLPs and nuclear microsatellites [16], included only five populations of Wych elm from Spain, of which one was from the Central System.…”