Changes of small mammal communities with the altitude gradient

The influence of altitude gradient on the animal communities in the Eastern Tatra Mountains of Slovakia has never been studied. There are some rare, endemic and relict animal species and even a group of small terrestrial mammals native to the Tatra Mountains. Between 2009 and 2014, research was conducted on the impact of altitude gradient on the species richness, abundance and composition of small mammal communities in the Eastern Tatras. In total, more than 16 species were trapped, including snow voles, tatra voles and alpine shrews, three species endemic to the Carpathian Mountains. The species richness of small mammals declined at higher elevations. The endemic alpine shrew was found at altitudes of 914 and 1007 m above sea level, while tatra voles were recorded almost along the entire gradient studied. Snow voles ranged only above the tree line at altitudes of 1574 to 1775 m, in the Rock slope habitat. On the other hand, generalists colonised various parts of the gradient at different altitudes, while specialists were bound to specific habitats whose presence was limited by altitude. The composition of small mammal communities evidently and significantly varied with rising elevation and with the biotope type in the area under observation. Our results suggest that the composition of the community reflects changes in environmental conditions and the biological limits of the particular small mammal species in the altitude gradient as well as the combination of neighbouring habitats and the resources they provide.