Open Access

Achille Casale, Augusto Vigna Taglianti

• A synthesis of the Carabid fauna of the Central and Eastern Alps and Pre-Alps, from a biogeographical point of view, is presented. Only the Italian side of the Alpine chain is considered, from the basin of the Toce river to the Trieste and Gorizia Karst. Main features of the landscape are: 1. an ancient orogenetic history and evolution, that made this area available to the colonization by carabids, of both gondwanaland and laurasian lineages, since the lower Tertiary; 2. a marked geological and geo-morphological complexity, with highest elevation at Pizzo Bernina m 4.049; 3. the presence of a very developed, dolomitic-calcareous and markedly carsified prealpine belt, rich of deep and large hypogean systems (also at high altitude), which makes this area highly different, from the geo-morphological point of view, from the Western Alps; 4. the geographic position, as a mountain chain of some 750 kms between central Europe and the Padanian plain, connected with the Caravanche and the Dinaric chain and close to the Adriatic sea in me Eastern part; 5. finally, a puzzled climate situation, that includes xero-thermic areas (500-700 mm of rain per year, also in some intra-alpine sectors), close to highly rainy areas - more than 2.500 mm per year - in the westernmost and easternmost parts of the chain. Thus, like in the Western Alps, sub-mediterranean vegetation types, dose to cool-moist forests, coexist with high-altitude environments above the timber line. These facts explain the heterogeneity, the richness, the variety, and the interest of the carabid fauna of the area: the highest number of species (658) ascertained so far, i.e. 112 of the whole Italian carabid fauna and about 115 of the carabid fauna cited so far for the Europe in politic sense, fi·om me Canary islands to the Urals; the high number of euri- or stenoendemites (204, i.e. abour 31 % of the species, 3/5 of which concentrated in the pre-alpine belt), and the complex origins and/or affinities of different taxa. A large number of species (174, i.e. 26%) belongs to European chorotypes (European, South-European or typically Alpine), and even more (255, i.e. 38%) to Holarctic (Holarctic, Palaearccic, West-Palaearctic, Asiatic-European, Siberian-European, Central-Asiatic-European, Central-Asiatic-European-Mediterrancan, Turanic-European, Turanic-EuropeanMediterranean, European-Mediterranean) chorotypes. This darum confirms the well known role, both of connection and separation, that the Alps as a whole played between Europe and the Mediterranean area. Furthermore, it is to be recalled the presence, in some localities of the Eastern Alps, of micro thermophilous, boreal species, like Miscodera arctica, now widespread in Northern regions of the Holarctic Region. Many orophilous, forest-dwelling, riparian and hygrophilolls species, are of northern, north-eastern, ruranic or dinaric-balkanian origin. A very small, bur interesting group of thermophilous elements (mostly Harpalini), originally from the Mediterranean area or temperate steppes, during the hypsothermic periods of the Pleistocene and Olocene, reached the Central and Eastern Alps and Pre-Alps, and persist in xerothermlc biotopes. Some of these could increase their range of distribution as a consequence human activities in agricultural use overgrazing and deforestation. Some others, like Carabus montivagus and Laemostenus algerinus, seem to be present owing to very recent anthropogenic introduction. From the biogeograpic point of view, however the most important group of species is represented by the impressive number of endemics (204, of which 116 species restricted to politic Italy), either eurendemics to Central and Eastern Alps and Pre-Alps, or stenoendemics to single sectors of the area or to very small biotopes (caves, isolated montane massifs): among these, we may cite some large-sized species like Cychrus cylindricollis, endemic at high altitude, to the Central Pre-Alps, several montane, very localized Trechus species, many subterranean, highly specialized Trechini of the peculiar genera Boldoriella, Orotrechus, Anophthalmus, Allegrettia, Italaphaenops, Lessinodytes: many Pterostlchini, and others, Most of them must be considered as pre-Quaternarian elements, With affinltl,es either til Gondwana (such as the blind Reicheina of the genus Alpiodytes), or in the Angarian (as the Broscosoma species) areas, They are, the result of an ancient, subtropical or temperate forest dweller Carabid fauna, tied now to soil: forest littter, superficlal subterranean environment, caves, and upper montane refugia, Both from floristic and faunistic informatlon, It IS a well known fact that the pre-alpine belt as a whole represents a large, unique Pleistocene refugium, that shows a scenario of marked isolation and speciation in mountains, valleys and hypogean compartments. The analysis of the entire Carabid fauna in the Central and Eastern Alps and Pre-Alps shows that the present composition and complexity is the result both of ancient clado-vicariance events and of recellt, ecological factors, These facts surprisingly make this area (not only concerning carabids) very close to important towns and to one of the most populated, cultivated and industrialized area of Italy (the Padanian plain), and in spite of its relatively small surface, one of the most important hot spar of biodiversity in Europe, in which many biotopes are presently highly endangered, or in some cases completely destroyed, A checklist of the Carabid species of the Central and Eastern Alps and Pre-Alps, with their chororypes, is added.