Proposed units of conservation in Ulmus laevis
We propose for U. laevis conservation the definition of evolutionary significant units (ESUs), and of management units (MUs) within these (Moritz, 2002). In plants, ESUs are defined by membership to monophyletic chloroplast lineages (rather than mitochondrial taxa) (Moritz, 1999; Newton et al., 1999). Given the three cpDNA haplotypes currently known for U. laevis (Whiteley 2004; this study), we propose two ESUs. The most widespread ESU would comprise populations from SW Europe through Central to Northern Europe possessing either haplotype A or B or both. Within this ESU, we suggest that each of the five BAPS microsatellite clusters (Figure 2) should be considered a discrete MU. Consideration of cluster B as a MU would be enough to preserve the cpDNA haplotype B without creating another ESU for it, something that by current criteria would not be supported due to the presence of two populations possessing both haplotypes A and B. The MU corresponding to cluster A would extend to the east as far as Russia, considering the homogeneity of Central European populations for both cpDNA and nuclear markers (Whiteley 2004; this study). We propose a sixth MU is for the Finish U. laevis populations shown by nuclear microsatellite data (Whiteley, 2004) and allozymes (Vakkari et al., 2009) to by significant differentiated from Central Europe. The second proposed ESU would comprise those Eastern Europe populations possessing haplotype C (Whiteley, 2004). However, since only two very distant (NE Greece, SW Russia) locations in this region have been sampled, more geographically widespread genetic data are needed to define the extent of this ESU and any possible subdivision into MUs.
Ulmus laevis proposed ESUs and MUs diagram
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