Habitat preferences of small terrestrial mammals in the mountain forest ...

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Sorex minutus. 1. -. 1. -. -. -. Crocidura suaveolens. 2 ... CCA Axis 1. CCA. A xis 2. Fig. 1: The first factorial plane of the canonical correspondence analysis ...
Beskydy, 2009, 2 (2): 195–200 © Mendelova zemědělská a lesnická univerzita v Brně ISSN: 1803-2451

Habitat preferences of small terrestrial mammals in the mountain forest clearings J. Suchomel1, J. Krojerová-Prokešová 2, M. Heroldová2, L. Purchart1, M. Barančeková2, M. Homolka2 doc. Ing. Josef Suchomel Ph.D., Ing. Luboš Purchart, Ph.D., 1Institute of Forest Ecology, Mendel University of Agriculture and Forestry, Zemědělská 3, 61300 Brno, Czech Republic, e-mail: [email protected] Mgr.  Jarmila Krojerová-Prokešová, RNDr.  Marta Heroldová,Ph.D., Mgr.  Miroslava Barančeková,  Ph.D., RNDr. Miloslav Homolka, CSc. 2Institute of Vertebrate Biology, AS CR, Květná 8, 60365 Brno, Czech Republic, e-mail: [email protected]; Abstract: Suchomel J., Krojerová-Prokešová J., Heroldová M., Purchart L., Barančeková M., Homolka M. 2009: Habitat preferences of small terrestrial mammals in the mountain forest clearings – Beskydy, 2 (2): 195–200 In last ten years strong intention to replace forest monocultures of coniferous species to mixed coniferous – broadleaved stands which are close to nature composition is promoted. Mountains forests under study are of different character. In Beskydy Mts forests of beech-spruce mixture prevail but in Jeseniky spruce monocultures prevail. In both, reforestation activities are complicated by impact of rodents and influence of industrial immission. Small mammal species were monitored during two successive years on clearings with artificial plantations. In both total abundance of species was similar but with different dominance of the species. Under influence of beech mast year Apodemus flavicollis was dominant in Beskydy Mts but Myodes glareolus in Jeseniky Mts. Higher dominance of Soricidae was in Jeseníky Mts (19%) against Beskydy (6%). The diversity and equitability was similar in both (Jeseniky Mts – 1.63, Beskydy Mts – 1.49; 0.84 resp. 0.72). Notable was the high dominance of Microtus agrestis (23 resp. 27%) in both. Abundance of the dominant species was synchronized. Canonic correspondence analyses (CCA) of clearing characteristics show the significant preferences of M. agrestis for higher elevation, more grassy and grassy wastage (higher humidity) environment. This was above all problem of emission clearings. As to M. glareolus, forest weeds preferably of Rubus sp. were responsible for its dominance. These results can contribute to understand rodent habitat preferences and help in prevention against their impact by the way of herb layer management. Key words: mountains, forest clearings, small mammal species, habitat preference Introduction Small terrestrial mammal species are natural and important part of mountain areas forests. From the  forestry point of view most of the  species significantly influence forest regeneration. But the  more detailed information about the  mutual relations is low especially when new situations in forestry management strategy starts. In reforestation, proportion of broad leaved trees compared to coniferous will increase in all Czech Republic areas. With this

strategy broad leaved trees are more negatively influenced by small mammal species especially by rodents (Bryja et  al. 2001a, b). Mountain forests, predominantly coniferous are above all also negatively influenced by industrial immissions (mostly in Beskydy Mts) and by destructive influence of strong winds (hurricanes mostly in Jeseniky Mts). Under these conditions some clearings are of large extent. Forest regeneration by forest plantings on such clearings needs a special attention to all negative factors.

195

196

J. Suchomel, J. Krojerová-Prokešová, M. Heroldová, L. Purchart, M. Barančeková, M. Homolka

The knowledge of environmental preferences of particular small mammal species, especially Microtus agrestis reported as a pest of young trees in mountains, is extremely important. It may help in better management of clearings as prevention against negative impact of rodent species. Small mammal communities were studied in Jeseniky Mts by Nesvadbova and Gaisler 2000 and in Beskydy Mts by Bryja et al. (2001b) and Suchomel et al. (2007), but in our contribution we concentrated on artificial forest plantation areas (various types of clearings in various elevations, not only immission one) and influence of habitat on small mammal distribution there. Another question was whether, in each of the two mountains system studied, same or different response of terrestrial small mammal communities on habitat variability would be expressed. Material and methods The  study was carried out in two mountain areas: Jeseníky Mts and Moravian-Silesian Beskydy Mts. Small mammal communities were monitored during two successive years (2007 and 2008) on clearings with artificial plantations. At the each study area 18 monitoring plots were

established, which differed in the habitat structure and age. Most of the plots were broadleaved trees plantations. Elevation extent was from 550 to 1205 m a.s.l. in Beskydy Mts and from 680 to 1185 m a.s.l. in Jeseniky Mts. The  trapping was realised during autumn. Snap traps were laid in lines of 34 traps each, 3 m apart so the  total length of each line was about 100 m. Traps were baited with peanut butter, exposed for three successive nights and inspected daily. The complete trapping effort was 7344 trap-nights, resulting in a total of 501 captured small mammals. To assess diversity of small mammal communities, frequently used indices, such as the number of species (S), Shannon’s index of diversity based on natural logarithms (H0), and Shannon evenness (E = H0/Hmax), were used. Vegetation composition of each monitoring plot was assessed (Table 1). The effect of habitat vegetation structure on small mammal community composition was analysed by canonical correspondence analysis (CCA) using Canoco 4.5 for Windows (Ter Braak & Šmilauer, 2002). We used Monte-Carlo permutation tests (499 permutations) to determine significance of the first canonical axis (Ter Braak & Šmilauer, 2002). Input data were square-root transformed.

Tab. 1: Inter set correlations of environmental variables with canonical axes. Abbreviations of vegetation variables used in biplot projection are given. Mapping variables elevation Monitoring plot (MP)

age

CCA1

CCA2

elevation

−0.171

−0.288

0.368

−0.002

agecl

cover of herb layer

coverE1

−0.198

0.057

height of herb layer

heightE1

0.139

0.184

cover of grasses

grasscl

−0.302

0.241

cover of forest weeds

weedcl

0.176

−0.036

cover of forbs

forbscl

0.157

−0.199

amount of grassy wastage

wastcl

−0.238

0.233

coverE2

0.292

0.116

height of shrub layer

heightE2

0.469

0.076

clearings

clearings

0.060

−0.185

sterile forests without understorey

sterilfor

0.029

0.089

cover of shrub layer

Surrounding of the MP

Abbreviations

old forests with understorey fertile beech/oak forests coniferous forests cover of grasses cover of forest weeds and other forbs

oldfor

−0.099

0.127

beech/oak

−0.086

0.382

confor

−0.105

0.242

grassur

−0.179

0.116

0.048

−0.188

weed/forbs

cover of herb layer over 50%

E1over50

−0.168

−0.150

cover of shrub layer over 50%

E2over50

0.125

−0.157



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Habitat preferences of small terrestrial mammals in the mountain forest clearings

Results and discussion In both mountains localities total abundance of species was similar but with different dominance of the species. Under influence of beech mast year in autumn 2007, Apodemus flavicollis was the  most dominant in Beskydy Mts but Myodes glareolus in mostly coniferous forests in Jeseniky Mts. Higher dominance of Soricidae was in Jeseníky Mts (19%) against Beskydy (6%). This was also reported by Nesvadbova and Gaisler (2000) where dominance of Sorex araneus was about 50% in Jeseníky Mts immission clearings. The  diversity and equitability was similar in both (Table 2). By Bryja et  al. 2001b highest diversity of species was found in Beskydy Kněhyně Mt. in small clearings with presence of both, forest as well as open habitats small mammal species. Notable was the high dominance of Microtus agrestis (23 resp. 27%) in both mountain areas. In Beskydy immission clearings in Smrk Mt. field vole was a dominant species (Bryja et al. 2001b). The  CCA performed to relate habitat effects on small mammal species abundance was significant (Monte Carlo permutation test of the first canonical axis: F-ratio = 12.352, P = 0.02). The first two canonical axes accounted for 20.8% and 12.5% of explained variance of species data,

respectively. Explained variance of species-environment relation was 47.1% and 28.4% by CCA axis 1 and CCA axis 2, respectively (Table 3). The first canonical axis of the CCA was mainly positively related to presence of fertile beech forests in the surrounding of the clearing. It represents the gradient from higher elevation with higher number of clearings in the  surrounding of the  monitoring plot (preferred by Microtus agrestis and Sorex araneus) to lower elevation in more forested areas (preferred by Microtus arvalis). The  second canonical axis was mainly positively related to height of shrub layer. It represents the  gradient from young clearings with high cover of herb layer formed mainly by graminoid species and presence of grassy wastage (preferred by Arvicolinae and by Sorex araneus) to older clearings with higher height and shrub cover with weed forest species (as Rubus sp.) dominating in herb layer (preferred by genus Apodemus) (Table 1, Fig.  1). By Heroldova et al. (2008a) distribution of small mammal species in artificial plantations is related above all to food availability and also on density of cover to shelter. Strong preference of field vole for grasses and grassy wastage is in accordance with our findings as particularly planting infested by grass cover is more exposed to harmful effects of

Tab. 2: Basic characteristics of small terrestrial mammal communities obtained at two localities in the Jeseníky Mts and Beskydy Mts. Jeseníky Mts

MS Beskydy Mts

2007

2008

07/08

2007

2008

07/08

Apodemus flavicollis

10

34

44

15

78

93

Apodemus sylvaticus

-

2

2

1

10

11

Apodemus sp.

-

2

2

-

-

-

Myodes glareolus

25

47

72

7

68

75

Microtus arvalis

9

5

14

2

4

6

Microtus agrestis

30

38

68

20

29

49

-

-

-

1

-

1 16

Microtus subterraneus Sorex araneus

38

6

44

14

2

Sorex minutus

1

-

1

-

-

-

Crocidura suaveolens

2

-

2

-

-

-

Muscardinus avelanarius

-

-

-

1

-

1

115

134

249

61

191

252

7

6

7

8

6

8

Number of trap-nights

1836

1836

3672

1836

1836

3672

I (ind./100 trap-nights)

6.3

7.3

6.8

3.3

10.4

6.9

Shannon diversity index

1.572

1.460

1.626

1.611

1.303

1.492

Shannon evenness

0.808

0.815

0.836

0.775

0.727

0.717

Total Number of species

198

J. Suchomel, J. Krojerová-Prokešová, M. Heroldová, L. Purchart, M. Barančeková, M. Homolka

Tab. 3: Results of canonical correspondence analysis. Statistic

Axis 1

Axis 2

Axis 3

Axis 4

Eigenvalues

0.271

0.163

0.091

0.050

Species-environment correlations

0.782

0.638

0.606

0.488

Total variance 1.302

Cumulative percentage variance of species data

20.8

33.3

40.4

of species-environment relation

47.1

75.5

91.3

44.2 100

Sum of all eigenvalues

1.302

Sum of all canonical eigenvalues

0.575

1.0

this species. On some plantations grasses of genus Calamagrostis were dominant. By Heroldová et al. (2008a) the cover of grasses was highly correlated with the  level of impact on young trees (r  = 0.8; p  = 0.01). On large immissions clearings on Smrk Mts. grasses were also the  dominant species. On that area great damage above all on broad leaved young trees was recorded (Heroldová 1995, 2002). The same situation was known from the other mountains immission areas as from Krušné Hory Mts. (Tichý 1977, 1987, Heroldová 1992). Open area grasses ecosystems

become suitable environment for field vole outbreaks and this species was the  main pest species damaging the  tree plantations (Bryja et  al. 2001a, b). Also shrub cover on plots was in negative correlation with damage (r = −0.51; p = 0.17) but with no  significant influence. On such plots mice species were in dominance. By Heroldová et al. (2008b) these species impact on forest regeneration is by tree seed predation.

Microarv

beech/oak

grasscl wastcl

confor

grassur

heightE1 oldfor

sterilfor

CCAAxis2

coverE1

coverE2 Apodflav

Sorexar Microagr Myodes

weedcl

heightE2 agecl

Apodsyl

E1over50

-0.8

E2over50 clearings weed/forbs forbscl elevation

-0.8

CCAAxis1

Fig. 1: The first factorial plane of the canonical correspondence analysis

0.8



Habitat preferences of small terrestrial mammals in the mountain forest clearings

Conclusion In both of the  mountains same habitat preferences of the  small mammal species were observed. Large clearings overgrown by grasses are the preferable habitat of the field vole. The forest regeneration by artificial tree plantation is then the most endangered on these localities. Vegeta-

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tion removals with herbicides, grazing or cutting are widely recognized control techniques for many rodent species (Gill 1992). But the herb layer manipulation as vegetation removal on reforestation plots is costly and in mountain terrain difficult to manage.

Acknowledgements The study was supported by NAZV QH72075, MSM 6215648902, and by LC06073.

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on the forest regeneration in artificial plantations in the Smrk – Kněhyně area. Beskydy. 1: 33–35. H eroldová, M., Suchomel , J., P urchart, L., Ho molka , M. 2008b: The  role of granivorous rodents in beech forest regeneration in the Beskydy Mts. (Czech Republic). Beskydy. 1: 131–134. Nesvadbová, J. and Gaisler, J. 2000: Communities of terrestrial small mammals in two mountain ecosystems influenced by air pollution. Folia Zoologica, 49: 295–304. Suchomel , J., H eroldová, M., P urchart, L., 2007: The study of changes in the synusia of small terrestrial mammals (insectivore, Rodentia) of top parts of the  Beskids (preliminary results). Beskydy, 20, 211–216. Ter Braak, C. J. F. & Šmilauer, P. 2002: CANOCO Reference manual and CanoDraw for Windows user‘s guide: Software for canonical community ordination (version 4.5). – Microcomputer Power, Ithaca NY, USA, 500 pp. Tichý, V. 1977: Hraboš mokřadní – nový vážný škůdce lesních výsadeb. [Field Vole – a new important pest of forest plantations.]. Lesnické práce, 56: 73–78. Tichý, V. 1987: Drobní myšovití hlodavci v lese a  ochrana proti nim. [Small murid rodents in forest and protection againts them.]. Lesnické práce, 66: 70–75.

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