ZEN lab
Numerical and
Experimental Zoology
Alps and Apennine: similar but different
The Apennines are recognized as one of the greatest centers of endemism of the Mediterranean, with a great number of endemic species and peculiar genetic lines, many of which are raised to species status as a result of in-depth studies.
The particular paleoecological and paleogeographic history of the Italian peninsula are at the base of this phenomenon. In fact, the Italian peninsula has remained climate-friendly for the life of many organisms through the long glacial peaks of the Pleistocene, while the Alps, covered by ice, made it in fact isolated.
Recognizing endemic elements within a fauna can be complicated. In fact, macroecological studies generally use entities recognized by taxonomists at the species level. This type of evaluation automatically excludes the recognition of the genetic lines that collect a fundamental component of diversity and on which philogeography is based. Consequently, genetic lines, even when they represent Evolutionarily Significant Units (ESU), are typically excluded from macroecological approaches and protection lists (e.g IUCN).
We collected more than 20,000 sequences of European butterflies. This dataset has allowed to demonstrate the existence in the European butterflies of one of the most important paradigms in philogeography, the presence of a greater genetic richness in the southern regions than in the northern ones (southern richness, northern purity).
In our work we hypothesized that it was possible to identify two different centers of endemism in the Alpine - Apennines region, generally referred to as a single biogeographical unit, the Italian refuge. The the Alps were covered by ice during the glaciations, while the Apennines were more available for the survival of butterflies. So the Alpine and the Apennine butterflies were characterized by different evolutionary histories. To verify this hypothesis we have answered three research questions:
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Is it possible to identify two different zoogeographic areas according to the distribution of the endemic entities of this region?
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Are alpine endemisms, closely linked to mountain environments, characterized by ecological traits less variable than those of the Apennines linked to more heterogeneous environments?
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Are Apennine endemisms largely represented by genetic lines evolved during the Pleistocene?
The results of our research show how the Apennine region represents a reservoir of genetic diversity for European butterflies and at the same time how it is imprecise to refer to the Alpine region-Apennines as a generic "Italian refuge" , least for the diurnal lepidopterans.
In fact, we have objectively identified two centers of endemism: the alpine area and the peninsular-Sicilian area. Only few butterflies are found in both areas despite the territorial continuity.
The endemisms of the two areas are not only characterized by strong spatial segregation, but also by different ecological traits and a different degree of genetic divergence that reveal how the two centers of endemism should be considered functionally different.
The presence of a large number of cold climate-loving species in the Alps and their low phylogenetic variability support the idea that these species were more widely distributed in steppe and tundra environments during the last glacial maximum and in the present interglacial they have taken refuge in the alpine areas forming a center of endemism of recent formation especially on the prairies above the lines of the trees.