Biogeographia – The Journal of Integrative Biogeography

The epikarst crustacean fauna from four Sicilian caves (Conza, Entella, Molara, and Zubbia del Cavallo caves) and four caves in the Lessinian Massif in the Venetian Prealps (Covolo della Croce, Ponte di Veja, Roverè Mille, Buso della Rana caves) was recently investigated. The two groups of caves differ in their environmental conditions: the Sicilian caves are fossil except one which has an active branch; they are all fed by strongly intermittent and scarce rainfall peaking in the fall. The Lessinian caves are fed by more abundant rainfall, with two yearly peaks (May-June and October-November); two of them are active, one has a temporary stream, one is fossil. The crustacean fauna found in the epikarst drip of each of the studied caves is characterized by interesting endemic harpacticoid and cyclopoid copepods, and one bathynellacean syncarid, often collected in only one cave. Higher diversity of stygobiotic taxa was recorded for the Lessinian caves (9 species of copepods in the Lessinian, and 6 species of copepods and one bathynellacean in Sicily); most of the taxa collected in Sicily are endemic to one cave. Spatial analysis showed very different distributions over short spatial scales (tens of kilometers) and, within each cave, the distribution also varied over distances of a few meters. Our data correspond with other studies where many epikarst crustaceans showed a distribution with a linear extent of only a few hundred meters: the epikarst fauna is not uniformly distributed but rather divided in “blocks” probably characterized by different environmental conditions and, as a consequence, by different taxocoenoses. The data highlight the epikarst as a source of “hidden” biodiversity, and the importance of management protection plans which include not only the caves, but also the epikarst overlying layer and the water sources that feed it.

Although there are various checklists of Italian mammals, there is not yet a synthesis of those mammals that are endemic to Italy. Therefore, we provide for the first time a detailed review on Italian mammal endemic species including endemic taxa deserving additional studies. This review is based on the most recent taxonomic revisions obtained using Scopus and Google Scholar databases. We also considered the age of endemic species. Some aspects of mammalian conservation are also provided and discussed.

Most free-living nematodes should have a global distribution if they would follow general tendencies of microbial organisms. Information on free-living nematodes presented in this review demonstrates that this cosmopolitanism is less common than assumed by theory. While very large distribution ranges are observed in a number of nematode species, various examples of endemism are described for isolated units like islands, extreme environments and ancient pre-Quaternary lakes. Endemism is generally rare among microorganisms, but a typical observation for larger organisms. The biogeography of nematodes thus reflects their intermediate position between macro- and microorganisms and future studies on this interesting group may help identifying why the positive relationship between body size and range size observed in large animals shifts to a negative relationship in microbial organisms.

Genetic rescue is a measure to mitigate the effects of reduced genetic variation in endangered small, isolated (inbreed) populations by introducing new genetic variation into such populations. This is usually accomplished by translocating individuals from a related population, assumed to belong to the same, often polytypic species, into the endangered population. If, however, the taxonomic classification does not reflect the ‘true’ diversity, genetic rescue can have detrimental effects on the survival of the endangered population (e.g. outbreeding depression). Here we point to problems if erroneous taxonomy informs such translocating strategies. Actions that promote artificial admixture of evolutionary lineages may be ineffective, or they may homogenize existing diversity and biogeographic patterns instead of protecting them. The extreme result is to drive target species and/or cryptic lineages to silent extinction. We single out conspicuous examples to illustrate the negative impacts of actions, which have resulted from artificial interbreeding of evolutionary distinct species or ill-conceived ‘genetic augmentation’. In such cases, translocations negate the overarching objective of biodiversity conservation: embodied in the concept of phylogenetic distinctiveness (PD), the encompassing scientific foundation of biodiversity conservation aims to maximize representation of the evolutionary history at the levels of species and ecosystems. A major underlying problem that we identify is persisting taxonomic inertia maintaining e.g., an overly simplified ungulate taxonomy, which is in most cases equivalent to a certain genomic incompatibility or a dilution of specific adaptations. Translocations and genetic rescue should only be employed, if potentially negative effects of the measures can be ruled out (including wrong taxonomy). Poor taxonomy has been – and indeed remains – at fault.