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Amori G.,CNR Institute of Neuroscience | Gippoliti S.,Italian Institute of Anthropology | Luiselli L.,Demetra s.r.l.

Some of the ecological correlates of threatened endemic island rodents across 31 main islands/archipelagos worldwide are studied. Overall, there were 83 entirely endemic genera and 197 endemic species, with the number of both endemic genera and species positively correlating with (log) island size. Twenty-seven rodent genera, and 49 species, endemic to islands, are threatened with extinction, with the Oriental region housing the highest numbers of endemic threatened taxa. There was a signifi cant positive relationship between (log) island size and number of threatened endemic species. The number of endemic species per island was also signifi cantly positively correlated with the number of threatened species per island. A logit model revealed that the probability of the presence of at least one threatened endemic species was 0 % for islands below 1560 km 2 , and 80 % for islands sized about 3120 km 2 . The mean body weight of endemic threatened taxa increased signifi cantly with increases of (log) island size (r = 0.144, n = 12, p = 0.0096), and was particularly high in the Caribbean islands. Our study indirectly supported the notion that species linked to habitat fragments ( = islands of remnant habitat) are more prone to extinction than species able to traverse suboptimal habitats ( = seas of unsuitable habitat). Our results also demonstrated that the number of threatened endemic species per island was dependent on the total number of endemic species in each island, thus showing that tropical islands may be more prone to include assemblages of threatened endemic rodent species than temperate islands. Endemic species inhabiting islands of about 1500 km 2 are of immediate conservation concern because of their high probability of becoming extinct in the years to come, given that their counterparts from even smaller islands are already extinct since decades or hundreds of years ago. © 2012 by Walter de Gruyter. Source

Amori G.,CNR Institute of Neuroscience | Gippoliti S.,Italian Institute of Anthropology | Battisti C.,Environmental Service Inc.
Community Ecology

Changes in taxa composition among different communities in a landscape or along an environmental gradient are defined as β-diversity. From a biogeographic point of view, it is interesting to analyse patterns of β-turnover across latitudinal bands, and to understand whether P-diversity is significantly associated with endemism at lower latitudes, as predicted by theory. We inspected these issues by using squirrels (Rodentia, Sciuridae) as a study case. Distribution data for each genus were obtained from literature and mapped. The two hemispheres were subdivided into 23 latitudinal bands of equal area, and we calculated a β-turnover index between latitudinal bands with two formulae: Wilson and Shmida's (1984) and Lennonetal.'s (2001) indices. We found that the peak of number of Sciuridae genera significantly corresponded to the peak in β-turnover scores at the same latitudes (25-31°N) with Wilson and Shmida's (1984), but not with Lennon et al.'s (2001) index. We also found that the turnover between ground and tree squirrels corresponded to the grassland vegetation latitudinal bands (around 40° N), and the beginning of the latitudinal bands characterized by tropical and subtropical forests is accomplished with the occurrence of tree and flying squirrels. Source

Amori G.,CNR Institute of Neuroscience | Masciola S.,CNR Institute of Neuroscience | Saarto J.,University of Rome La Sapienza | Gippoliti S.,Italian Institute of Anthropology | And 3 more authors.
Biodiversity and Conservation

Comparing species checklists across countries can be important for determining the relative uniqueness of each country, which can be conveniently defined on the basis of the number of species occurring only in that country or, at most, in one of its neighboring countries. Production of accurate country checklists is complicated by the fact that, especially in scientifically neglected regions, the knowledge of the distribution of many species is unsatisfying. When distribution of a given species is insufficiently known, typically there may be apparent gaps in its distribution range. These species are defined here as 'gap species'. In this paper, we analyze the country checklists for rodents and insectivores of the African continent with the aims of (i) identifying the countries having a higher taxonomic uniqueness; (ii) highlighting countries where more research is needed; (iii) producing a list of gap species; and (iv) determining the ecological correlates of being a gap species. For both mammal groups, the important countries because of their low numbers of shared species were D. R. Congo, Cameroon, Sudan, Kenya, Tanzania, and South Africa. The countries with highest percentages of endemic taxa were Kenya, South Africa, Somalia and Tanzania for insectivores, and Ethiopia and South Africa for rodents. The number of gap species per country was 0-5 for both insectivores and rodents, with the only exceptions of Togo (12) and Benin (15). Apart from Togo and Benin, the main gap countries for rodents were Nigeria, Chad, Gabon, Burundi, and Rwanda, and for insectivores were Niger and Chad. In both groups, the number of gap species per country was independent on the country area, and both range and body sizes did not influence the probability for a species to have distribution gaps. However, most gap species were tropical forest inhabitants. The biogeographic and conservation implications of these data are discussed. © 2012 Springer Science+Business Media B.V. Source

Amori G.,CNR Institute of Neuroscience | Gippoliti S.,Italian Institute of Anthropology | Luiselli L.,Demetra s.r.l.
Biodiversity and Conservation

Biodiversity hotspots are used widely to designate priority regions for conservation efforts. It is unknown, however, whether the current network of hotspots adequately represents globally threatened taxonomic diversity for whole plant and animal groups. We used a mammalian group traditionally neglected in terms of conservation efforts, the rodents, in order to test whether biodiversity hotspots match the current distribution of threatened taxa (genera and species). Significantly higher numbers of threatened rodent genera and species fell within biodiversity hotspots; nonetheless over 25% of the total threatened genera and species did not occur in any biodiversity hotspot. This was particularly true for the Australian region, where 100% of the threatened genera and species fell outside biodiversity hotspots, with many threatened taxa found in Papua-New Guinea. We suggest to officially including Papua New Guinea among biodiversity hotspots for rodents, and also the steppic/semidesert areas of central Asia. © 2011 Springer Science+Business Media B.V. Source

Coia V.,University of Trento | Boschi I.,Catholic University | Trombetta F.,Catholic University | Cavulli F.,University of Trento | And 6 more authors.
Journal of Human Genetics

Although essential for the fine-scale reconstruction of genetic structure, only a few micro-geographic studies have been carried out in European populations. This study analyzes mitochondrial variation (651 bp of the hypervariable region plus 17 single-nucleotide polymorphisms) in 393 samples from nine populations from Trentino (Eastern Italian Alps), a small area characterized by a complex geography and high linguistic diversity. A high level of genetic variation, comparable to geographically dispersed European groups, was observed. We found a difference in the intensity of peopling processes between two longitudinal areas, as populations from the west-central part of the region show stronger signatures of expansion, whereas those from the eastern area are closer to the expectations of a stationary demographic state. This may be explained by geomorphological factors and is also supported by archeological data. Finally, our results reveal a striking difference in the way in which the two linguistically isolated populations are genetically related to the neighboring groups. The Ladin speakers were found to be genetically close to the Italian-speaking populations and differentiated from the other Dolomitic Ladins, whereas the German-speaking Cimbri behave as an outlier, showing signatures of founder effects and low growth rate. © 2012 The Japan Society of Human Genetics All rights reserved. Source

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