Application of the unified species concept reveals distinct lineages for disjunct endemics of the Brassica repanda (Brassicaceae) complex

Species delimitation is an important issue in terms of conservation priorities, especially for narrow endemics under threat of extinction. The Alpine endemics Brassica repanda subsp. glabrescens and subsp. baldensis belong to a highly polymorphic species complex, although their disjunct distribution suggests favourable conditions for independent evolution. In the present study, we applied the unified species concept to test whether the endemics form distinct evolutionary lineages, both from one another and also from the remainder of the complex. Compliance with the criteria of monophyly, diagnosability, and genotypic clustering was examined, primarily by making use of amplified fragment length polymorphism data. Both endemics were indicated as monophyletic by phylogenetic analyses, and diagnostic characters were found for both taxa. Population structure analyses showed clear genetic discontinuity for each of the endemics, with little admixture among the clusters. This evidence indicates that the endemics have acquired multiple properties that satisfy each of the species criteria considered. Hence, we suggest the taxonomic recognition of B. baldensis and B. glabrescens as separate species. Comparative population genetics analyses show the lack of marked genetic structuring within either taxon, as well as low levels of heterozygosity. Conclusions on the status of threat and on recommended conservation actions are drawn. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 482–497.     

Experimental design and taxonomic scope of fragmentation studies on European mammals: current status and future priorities

• 1 Habitat loss, habitat fragmentation and habitat degradation are the greatest threats to mammals in Europe and the rest of the world. Despite the fact that extensive literature exists, no comprehensive review or synthesis is available to date and this may slow down scientific progress and hamper conservation efforts.
• 2 The goal of this study is to understand if and in what direction progress has been made in the study of the effects of habitat loss and fragmentation on the spatial distribution of European terrestrial mammals. Firstly, we carry out a general synthesis which is structured around 11 key points. The aim of this point‐by‐point analysis is to identify trends, knowledge gaps and any significant bias in the available literature, and to highlight strengths and shortfalls of the different approaches which have to date been applied. Secondly, we follow a species‐specific systematic approach: for each species, we synthesise key results.
• 3 Our results show how substantial progress has been hampered for several reasons including: a large predominance of small‐scale field studies of short duration, and a generalised lack of control of: (i) confounding variables; (ii) spatial autocorrelation; and (iii) false absences. Also, despite the relatively high number of studies, few were theoretical studies and even fewer were meta‐analyses. The lack of meta‐analyses is likely to be due to the small amount of crucial details included in the publications, such as model parameters or information on the landscape context (such as the amount of residual forest cover).
• 4 We synthesise the main results for 14 species. The level of progress is highly variable: for some species, such as the red squirrel Sciurus vulgaris, a series of long‐term, large‐scale process‐oriented studies has allowed an in‐depth understanding of its ecology in fragmented landscapes. On the other hand, with other species such as the bank vole Myodes glareolus, despite a relatively large number of field studies, little progress has been made.

     

Evidence of a complex phylogeographic structure in the common dormouse,Muscardinus avellanarius (Rodentia: Gliridae)

This is the first mitochondrial phylogeography of the common dormouse, Muscardinus avellanarius (Linnaeus, 1758), a hibernating rodent strictly protected in Europe (Habitat Directive, annex IV; Bern Convention, annex III). The 84 individuals of M. avellanarius, sampled throughout the distributional range of the species, have been sequenced at the mitochondrial DNA gene (cytochrome b, 704 base pairs). The results revealed two highly divergent lineages, with an ancient separation around 7.7 Mya and a genetic divergence of 7.7%. Lineage 1 occurs in Western Europe (France, Belgium, and Switzerland) and Italy, and lineage 2 occurs in Central–Northern Europe (Poland, Germany, Latvia, and Lithuania), on the Balkan Peninsula, and in Turkey. Furthermore, these two lineages are subdivided into five sublineages genetically isolated with a strong geographical association. Therefore, lineage 1 branches into two further sublineages (Western European and Italian), whereas lineage 2 contained three sublineages (Central–Northern European, Turkish, and Balkan). We observed low genetic diversity within the sublineages, in contrast to the significant level of genetic differentiation between them. The understanding of genetic population structure is essential for identifying units to be conserved. Therefore, these results may have important implications for M. avellanarius conservation. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 648–664.