The Atlas illustrates the distribution in Umbria of 26 species of Erinaceomorpha (1), Soricomorpha (11) and small Rodents (14), a group without taxonomic validity but with strong ecological, ethological and operative resemblance.
Their presence is documented by 1726 records, all regularly georeferenced, referred to the period between the end of the 19th century and the year 2012 and mainly collected without a standardized method. The collected records have been divided in historical records (up to 1994), recent records (1995-2001 included) and contemporary records (2002-2012 included) .
The 202 historical records have been useful to trace the research phases on small Mammals in the region and to re-construct the previous areal of species that are nowadays very localised (Arvicola amphibius). Due to the necessity of updating them, these records have been excluded from any distributional and ecological assessments with the exception of maps (if not differently indicated) and of mortality cause assessment.
With the exclusion of the alien species Sciurus carolinensis the ascertained species are representative of 62,50% of Italian small Mammals. Records have been collected in 321 of 384 sampling squares (km 5 per km 5 according to the Gauss-Boaga grid) covering 83,90% of the regional territory. 4 of them (1,25%) include only historical records.
The regional chorology of the species is calculated by index of diffusion deriving from the ratio ID=number of cells where the species occurs/total of examined cells, whereas ID=0, the species doesn’t occur in any cell, ID=1, the species occurs in all cells. Talpa caeca, Sorex antinori, Neomys anomalus and S. carolinensis are new species for the region taking into account the data achieved by previous surveys (Ragni, 2002). Sciurus vulgaris, Erinaceus europaeus, Microtus gr. savii, Rattus rattus and Apodemus sylvaticus have reached the highest percentage cover values (from 46 to 26%).
N. anomalus, S. carolinensis, A. amphibius, Micromys minutus, T.caeca and S.antinori, result extremely localised and are present in a percentage equal or inferior of 2%. Umbria hosts the 3 Italian species of genus Talpa and 2 (7,69%) national endemisms, Talpa romana and S. samniticus, one species (3,85%), M. avellanarius, that is specially protected by the the Habitats Directive 92/43/EEC, one alien and problematic species, S. carolinensis, 4 species (15,38%) risking extinction, Neomys fodiens, S. vulgaris, A. amphibius and M. minutus.
Considering the taxa of Italian small Mammals presently known, their distributional areals and the diagnostic doubts for some of them, it is possible to consider that the species recorded here are between 79 and 100% of the ones really present in Umbria. The distributional deficiency gap due to the lack of sampling and to the different degrees of detectability of species, even those ones with similar life habits, have certainly favoured some areas instead of others.
For every species it has been moreover indicated:
- the general biological notes;
- categories of the nature of the records;
- biometry of Umbrian samples;
- possible useful diagnostic features;
- association with environmental elements (when possible, this assessment has been performed with reference to the bioclimatic categories, to the land use categories and using the information on the habitat where data had been found);
- categories of regional threats according to the guidelines and criteria indicated by the International Union for Conservation of Nature and Natural Resources (IUCN).
Future researches could add new useful information for the understanding of these small animals, most of them suffering the anthropic pressure due to the great modifications in the territory.
These considerations suggest a constant monitoring and measures to contrast the degradations of habitats damaging the most vulnerable species.