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 insecteating 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, Shorttailed 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 19951996,
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 19942003 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
vole
Red-backed
Rott-vole
vole
Short-tailed
vole
Lemmings, 2
species
Shrews, 4
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
change
1.47
2.31
2.0
1.33
-
0.78
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
vole
Red-backed
Rott-vole
vole
Short-tailed
vole
Lemming, 2
species
Shrews, 4
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
specimens per 100 trapsdays
Abundance dynamics of grey-sided vole at Kalkupya and
Rovvavaarra stations, 1994-2012.
40
35
30
25
20
15
10
5
0
Years
Kalkupya
Rovvavaarra
specimens per 100 trapsdays
Abundance dynamics of red-backed vole at the stations of
Kalkupya and Rovvavaarra, 1994-2012.
25
20
15
10
5
0
Years
Kalkupya
Rovvavaarra
Abundance dynamics of common shrew at the stations
of Kalkupya and Rovvavaara, 1994-2012.
specimens per 100 traps-days
16
14
12
10
8
6
4
2
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 greysided 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!