Species composition and community structure of small mammals in Parapolsky Dol (Koryak State Nature Reserve, Kamchatka)

Abstract

Parapolsky Dol is one of the largest wetlands of world importance. However, there is only fragmentary information about the species composition and structure of animal communities in this area, due to its inaccessibility. This fact determines the relevance of studying small mammals as an indicator group in Parapolsky Dol. The article deals with the results of a research on the fauna and small mammal communities of Parapolsky Dol (Koryak State Nature Reserve), carried out from 25 August to 15 September 2017. The study area included the shore of Lake Talovskoye, the floodplains of the River Tylakrylvayam and the River Ichiginnyvayams. During the period of 2735 trap-nights and 144 cylinder-nights we captured 5 small mammal species: Myodes rutilus, M. rufocanus, Sorex isodon, S. caecutiens and Ochotona hyperborea. The surveyed habitats ranged from the maximum to the minimum abundance of small mammals: the floodplain of the River Ichiginnyvayam – 10.9 individuals/100 trap-nights, 8.0 individuals /100 cylinder-nights; the shore of Lake Talovskoye – 3.48 individuals/100 trap-nights; the floodplain of the River Tylakrylvayam – 1.43 individuals/100 trap-nights, 2.53 individuals/100 cylinder-nights. The largest number of species (4) was captured in the habitats with woody vegetation and berry beds. The results of the capture by snap traps revealed the tendency of M. rutilus and S. rufocanus to dominate in most habitats. The results of the capture by cylinders show that S. caecutiens is dominant in the surveyed open habitats. All studied communities are characterised by low diversity indices, average values of dominance index, sufficiently high evenness and low sustainability. One can explain such structure of small mammal communities by the zonal and climatic conditions of the territory. The diversity/evenness structure in all the communities corresponds to that of the natural habitats in central, southern Kamchatka and Siberia. The small mammal communities on the shore of Lake Talovskoye and the floodplain of the River Ichiginnyvayam are characterised by high diversity indices, while the communities of the floodplain of the River Tylakrylvayam are distinguished by a high evenness index. We observed animal reproduction in the small mammal communities (pregnant and lactating females of different age groups were captured). The largest number of pregnant females and embryos, the highest values of reproductive success, indices of conservation and the generalised indices of well-being were identified in the small mammal communities in cedar and birch ribbon forests on the shore of Lake Talovskoye and in floodplain of the River Tylakrylvayam. In the plant associations Ledum decumbens + Vaccinium uliginosum – Cladonia sp. + Cladina sp., and Ledum decumbens + Vaccinium uliginosum – Sphagnum sp. we did not observe any reproduction. The material of this research work supplement the data on the fauna and population structure of small mammals in Parapolsky Dol.

Keywords

• Beringian forest-tundra
• common shrews
• relative abundance
• small land rodents
• species diversity