Community Dynamics of Small Mammals Micromammalia in North-Taiga Lapland G. KATAEV

Community dynamics of small mammals Micromammalia in north-taiga Lapland

G. KATAEV Location of stations for monitoring of Micromamaalia in Eastern Fennoscandia Introduction. Population monitoring of small mammals and abundance dynamics of individual species are relevant zoological objectives. The studies of microtine rodents and insect-eating mammals at the interface of the areas of species are of particular significance. Climate transformations and pollution of the air basin may influence the distribution, abundance and correlation of the species (Kataev et al., 1994; Ims, Fuglei, 2005; Kataev, Okulova, 2010). Apart from applied significance the long-term population studies of small mammals have some basic character: they contribute to the knowledge of functional pattern of northern ecosystems. The most long-term species abundance monitoring of land mammals in the Barents Sea region was carried out at the stations of Northern Fennoscandia and Scandinavia (Fig.1). The studies of rodents has been carried out at the monitoring sites of the Lapland reserve since 1936, in Kilpisjarvi – since 1946, in Kandalaksha reserve since 1952 and at Finse station in western Norway – since 1970 (Koshkina, 1957; Semenov-Tyan-Shanskiy, 1970; Kataev, 2012; Kataev et al, 1994; Henttonen, 1997; Henttonen, Wallgren, 2001; Framstad, 1995; Stenseth, 1999; Stenseth, Saitoh, 1998; Angeborn, et al., 2001). The establishment of a Russian-Norwegian reserve Pasvik in the Paz River valley in 1994 provided another opportunity for population and demographic monitoring of small mammals in the border area (Wikan et al., 1994; Makarova et al., 2003). The population studies of mammals based on long-term population monitoring are most successful in reserves and specially protected areas and recommended by the Seville Strategy (1996). Materials and methods. A comparative study of biodiversity and abundance of small mammals began in 1994 simultaneously in Pasvik reserve (Russia) at Kalkupya station (N 69°16’ E 29° 23’) and in Ser-Varanger commune (Norway) at Rovvavarra stationary (N 69°28’ E 29°51’). The first station is located 55 km to the south and the latter – 15 km to the south-west of the Pechenganikel smelter in the town of Nikel of the Murmansk region The stations are located in similar landscapes and geobotanic conditions. Both trap-lines are located on the slopes with eastern exposition and spread in bottom-top direction. The area belongs to open boreal woodlands. Kalkupya monitoring station is located on a similarly-named mountain massif with maximum height of 357 m above sea level. Rovvavarra station is located on the similarly-named mountain massif with maximum height of 245 m above sea level.

Results and discussion. There are altogether 34 mammal species on the territory of the Russian-Norwegian reserve Pasvik (Wikan et al., 1994). The fauna Micromammalia of the studied region is represented by the following rodents Myomorpha and insect- eating species Soricidae: Pygmy shrew – Sorex minutus, Sibirian shrew Sorex minutussimus, Common shrew – S. araneus, Graves shrew – S. isodon, Masked shrew – S. caecutiens, Water shrew – Neomys fodiens, Northern Bad – Eptesicus nilssoni, Wood Lemming – Myopus schisticolor, Norwegian Lemming – Lemmus lemmus, Red-backed vole – Myodes rutilus, Grau-sided vole – Myodes rufocanus, Water vole – Arvicola terrestris, Muskrat – Ondatra zibethica, Short- tailed vole – Microtus agrestis, Rott vole – M. oeconomus, Brown rat – Rattus norvegicus, House mouse – Mus musculus. The received data on species correlations of small mammals and their abundance at the stations are given. The analysis of these two time series showed that grey-sided vole, red-backed vole and common shrew are dominating species out of 11 registered species. Small-numbered species are rott vole, graves shrew and pygmy shrew. During 19 years of study the maximum abundance index for grey-sided vole was registered at Rovvavarra station and for red-backed vole – at Kalkupya station. During the whole study period at Rovvavarra the population peaks of red-backed vole were registered in 1995- 1996, 2001-2002, 2006-2007 and 2010-2011, and depressions in 1998-1999, 2003-2004, 2008-2009 and 2012. The population peaks of grey-sided voles were registered at this station in 1997-1998, 2002-2003, 2006-2007 and 2010-2011, and depressions in 1995, 1999-2000, 2004-2005 and 2008-2009. The abundance of red-backed vole in Rovvavarra station has been 3,6 times lower than in Kalkupya for the whole monitoring period. The first one is located much closer to the Pechenganikel smelter and to a large extent subjected to chemical pollution. It is known that wastes of metal production depress the state of the red-backed population. It was found out that the level of industrial emissions from the Pechenganikel smelter has started remarkably reducing since 2002. We compared the abundance of voles in Rovvavarra station during the periods of 1994-2003 and 2004-2012. It tuned out that during the last period the abundance of red-backed vole increased on average 2.3 times and of grey-sided vole - 1.5 times. Probably the faster growth of red-backed vole is a species specific reaction of this rodent to environmental improvement in the area. According to autumn records the abundance levels of red-backed vole change in both stations, which is typical for this study area having considerable cyclicity (Stenseth, 1999, Okulova, Kataev, 2003). In 1994- 2003 the population of red-backed vole in Rovvavarra station entered each phase of the population cycle ahead of schedule. Abundance peaks of two most abundant vole species: red-backed and grey-sided voles take place in the same years, but differ in height. The cyclicity indices s=0.946 and 1.471 respectively testify to considerable cyclicity of population of these species. The populations of common shrew are characterized by low cyclicity, s=0.602. The populations of grey voles Microtinae turned out to be not cyclic. (s< 0.5). Abundance dynamics of Micromammalia (specimens per 100 trap-days, improved value) at Rovvararra station during the periods of 1994-2003 and 2004-2012.

Years Grey-sided Red-backed Rott-vole Short-tailed Lemmings, 2 Shrews, 4 species vole vole vole species

1994-2003 12.6 1.6 0.3 0.3 0 5.9

2004-2012 18.5 3.7 0.6 0.4 1.8 4.6

Ratio of 1.47 2.31 2.0 1.33 - 0.78 change

Abundance dynamics of Micromammalia (specimens per 100 trap-days, improved value) at Kalkupya station during the periods of 1994-2003 and 2004-2012.

Years Grey-sided Red-backed Rott-vole Short-tailed Lemming, 2 Shrews, 4 species vole vole vole species

1994-2003 5.0 7.5 0.4 0.4 0.0 6.6

2004-2012 10.4 11.1 0.1 1.3 0.7 5.1

Ratio of 2.08 1.48 0.25 3.25 - 0.77 change Abundance dynamics of grey-sided vole at Kalkupya and Rovvavaarra stations, 1994-2012.

- 40 35 30 traps 25 20 15

days 10 5 0 specimens per 100 per specimens Years

Kalkupya Rovvavaarra

Abundance dynamics of red-backed vole at the stations of Kalkupya and Rovvavaarra, 1994-2012.

- 25 20 15 10

days 5 0

specimens per 100traps per specimens Years

Kalkupya Rovvavaarra Abundance dynamics of common shrew at the stations of Kalkupya and Rovvavaara, 1994-2012.

14 days - 12

2 specimens per 100traps per specimens 0

Yars

Kalkupya Rovvavaarra Conclusion. The population dynamics of small mammals in mountain landscapes of an international nature reserve Pasvik was studied during 1994-2012. The data analysis displayed biodiversity and quantitative changes in the populations of the studied species. During 19 years 8 species of small mammals were registered. It is found out that grey-sided vole is a dominating species in Rovvavarra station and common shrew and red-backed vole are dominating species in Kalkupya station. All species qualified as rare were registered in both stations. The comparison of dominating species abundances showed that, the highest abundance was registered for grey- sided vole in Rovvavarra station and for common shrew and red-backed vole in Kalkupya station. Long term abundance waves were traced and it showed that population cyclicity of the dominating species is similar in the study area. Chronological-specific analysis of vole population characteristics revealed peculiarities of interannual abundance and species correlations of grey-sided and red-backed voles in Rovvavarra and Kalkupya stations. The analysis of small mammal communities revealed differences in species composition and abundance of the animals living at various distances from the Pechenganikel smelter. The field sites demonstrate decrease in species diversity and abundance of animals compared to reference levels. It was found out that the species sensitive to sulfur dioxide and heavy metal pollution of the environment are red-backed vole out of mouse-like rodents and shrews out of insect-eating mammals. Judging from the reaction to local type of pollution the local population of red-backed vole turned out to be more sensitive compared to shrew population. The received time series of population dynamics of small mammals are quite long term and can be a basis for forecast of population boom of mouse-like rodents in the study area. The rare species such as Norwegian and wood lemmings make an exception. It is difficult to forecast the uprise of their abundance basing on available data. The continuation of record and inventories in Eastern Fennoscandia is an urgent research and nature conservation issue. It is important on the one hand due to necessity in new data about the animals inhabiting the range limits of the species and on the other hand a need in zoological monitoring of the natural environment in the region subjected to anthropogenic influence and climate transformations. Thank you for your attention!