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Collembolan assemblages of polar deserts and subarctic nival communities
Pedobiologia 44, 421–429 (2000) © Urban & Fischer Verlag http://www.urbanfischer.de/journals/pedo
PROCEEDINGS OF VTH INTERNATIONAL SEMINAR ON APTERYGOTA, CORDOBA 1998
Collembolan assemblages of polar deserts and subarctic nival communities Anatoly Babenko Severtsov Institute of Ecology & Evolution, Russian Academy of Sciences Moscow 117071, Leninski pr., 33, Russia Accepted: 12. October 1999
Summary Collembolan assemblages were studied in two different regions of the Arctic, on the Severnaya Zemlya Archipelago and upon the Putorana plateau (Southern Taimyr). The comparison of assemblages, developed in similar plant associations of the polar desert zone and of nival belt of Subarctic mountains, revealed that there are no common features in their species composition even though their structures were similar. This fact could be considered as an additional argument of the biota uniqueness of the polar desert. Keywords: Collembola, population structure, zonal and extrazonal polar deserts
Introduction According to zonal typology accepted in Russia (see, for instance, Chernov 1975), treeless territories of the Subarctic1 mountains (so called ‘alpine tundra’) should be regarded as extrazonal landscapes, i.e. an analogue of a zonal community formed out of zone boundaries. It is well known that both the species composition and the structure of plant cover there and in the true tundra are similar (for review see Walter & Breckle 1989). Does this similarity include other components of the ecosystem, such as the soil invertebrates?
1 this term is used here in its English version, i.e. to the south of the Arctic. In Russian scientific papers this territory is usually called Hypoarctic whilst Subarctic means southern part of the Arctic (= Low Arctic of the western authors) (for additional explanations see Chernov & Matveyeva, 1997)
0031–4056/00/44/03–04–421 $ 12.00/0
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The present study on Collembola as one of the invertebrate groups of major importance in Arctic soils should answer this question.
Materials and Methods In 1996–1997 soil microarthropods were studied in the western part of the Putorana plateau (Dynkengda Mt., surroundings of Yt-kyuel lake, 69° 09’N 91°52’E) on the altitude transect from 600 to 1000 m above sea level. This region is situated within the northern taiga (about 100 km southward of the latitudinal timberline), but on the studied altitudes tundra-like plant associations do exist. Sampling was carried out in four main types of vegetation. Three of them are analogous to tundra communities, viz. frost-boil Dryas-sedge-moss tundra (association Carici arctisibiricae – Hylocomietum alaskani), Dryas cover on stony outcrops (association Rhytidio rugosi – Dryadetum punctatae), and sedge-moss bog (association Meesio triquetris – Caricetum stantis). The fourth is the most similar to the polar desert communities. Below only some results of this study, devoted to Collembolan assemblages of the latter vegetation type, will be described and discussed. These plant associations develop above 700 m in the places where snow cover remains over a long period of time. Vegetation cover of these sites is similar to the typical zonal associations of the polar desert having identical community structure and many plant species in common including vascular plants, mosses and lichens, but considerably poorer. Floristically these nival deserts are also comparable with snowbed communities of the tundra zone, namely with the association Deschamsio-Cerastietum regelii. Detailed floristic descriptions of all these plant associations can be found in Matveyeva’s papers (1994, 1998). The data on Collembola from the true polar desert is based on a new material collected in 1997–1998 by Dr. O. Makarova in zonal polar desert communities of Bol’shevik Island (Severnaya Zemlya archipelago, 78° 11’N 103° 15’E). The following results are based on the analysis of more than 400 soil samples (25 cm2, depth 5 cm). In each of studied plant associations samples were taken according to the existing vegetation mosaic to obtain the most representative estimation for the whole habitat. Statistical procedures were performed by the program BIODIV 5.1 (Baev & Penev 1995) and the standard Statistical program for Windows.
Results Thirty two Collembola species have been recorded from Severnaya Zemlya (Babenko & Bulavintsev 1987; unpublished material of 1987–1988). About ten of them are found in practically all plant associations existing there (Table 1) and these very species constitute most of the polar desert fauna throughout the Palaearctic. All the other species known from the archipelago localized usually in the warmest biotopes and were not abundant even there. Among these “southern” species there are some widespread and polyzonal forms (for instance, Megalothorax minimus, Jeannenotia stachi (Jeannenot), Pseudanurophorus alticolus, and Willemia scandinavica), but the most of the Collembola of the Severnaya Zemlya are typical High-Arctic forms. As a rule, their distribution is not restricted to the polar desert (Vertagopus brevicaudus is an exception) and they are often found in communities of the tundra zone and southwards only in mountains. The most striking feature of collembolan assemblages of the polar desert is their abundance (Table 1). They exceed not only the abundance of all other groups of soil
Bog
– 1.04 1.86 0.02 64.64 5.80 1.35 1.65 0.88 1.90 0.49 20.20 0.19 – – – – – – – – – – 12 1568.6
– 0.77 5.78 5.60 64.50 7.00 3.58 0.91 1.09 0.53 0.41 9.75 0.09 – – – – – – – – – – 12 2437.3
Zonal Snow-bed community
species marked in bold are the most typical for the Palaearctic polar desert
Isotoma tschernovi Martynova 0.94 Hypogastrura sensilis (Folsom) 0.39 Oligaphorura groenlandica (Tullberg) 3.07 Hypogastrura tullbergi (Schäffer) 1.68 Folsomia binoculata (Walgren) [= F. regularis auct.] 68.81 Vertagopus pallidus Martynova 23.13 Vertagopus brevicaudus (Carpenter) 0.19 Agrenia bidenticulata Tullberg 0.36 Hypogastrura trybomi (Schött) 0.49 Hypogastrura longispina (Tullberg) 0.81 Anurida polaris (Hammer) 0.13 Folsomia taimyrica Martynova – Bonetogastrura nivalis (Martynova) – Megalothorax minimus (Willem) – Anurida alpina Agrell – Stenacidia sp. – Corynothryx borealis Tullberg – Pseudanurophorus alticolus Bagnall – Willemia similis Mills – Willemia scandinavica Stach – Protaphorura pjasinae (Martynova) – Hypogastrura concolor (Carpenter) – Folsomia alpha Grow & Christiansen – Number of species 11 Density (ind./dm2) 1374.1
Species/Biotopes
6.32 1.12 0.29 88.63 0.80 1.19 – 0.34 0.09 – – – – – – – – – – 11 5501.1
– 1.03 0.11 0.05 75.51 12.49 0.35 0.06 0.16 0.03 – 2.91 – 3.91 0.48 0.06 – – – – – – – 12 2498,2
– – 2.98 1.06 46.69 28.44 0.72 0.03 – – 2.69 3.01 2.72 1.82 0.09 – 0.03 1.16 0.06 – – – – 14 1383,5
– – 2.75 9.81
47.78 6.78 0.16 0.56 0.09 0.26 1.89 17.12 0.74 0.20 – – 0.01 0.13 0.06 0.01 0.04 3.65 0.20 19 1719,9
– – 16.76 3.55
Stream Patches of Rhacomitrium Lemming bank Carex ensifolia lanuginosum nests arctisibirica mat
Table 1. Species composition and abundance (%) of Collembola in the main plant association on the Severnaya Zemlya archipelago (August, 1997)
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microarthropods there but Collembola abundance both in the tundra zone and more southern forest habitats as well. Collembolan assemblages developed there include only one dominant species (Fig. 2) and its density usually comprises more than a half of total population. Extreme polytopy of the majority of Collembolan species is characteristic of the polar desert zone. Due to this polytopy, changes in relative densities of certain species but not in species composition do exist from site to site. Another typical feature of spatial distribution of Collembola in the polar desert is that many species which prefer extremely wet sites in the tundra (Hypogastrura spp., Agrenia bidenticulata, Folsomia binoculata, Anurida polaris, etc. ) inhabit there zonal plain communities. Fauna of the studied part of the Putorana plateau is mainly boreal and more diverse (no less than 100 species have been recorded). 53 species have been found regularly above the timberline upon the plateau. Among them there are widespread, polyzonal and boreal forms. Some typical High-Arctic species, for example, A. bidenticulata, Hypogastrura trybomi, H. tullbergi, Vertagopus pallidus, Anurida polaris, Isotoma violacea have been also found. These true Arctic forms are not numerous in any of the studied biotopes, except for the nival ones where I. violacea is one of the dominants. Changes in Collembola assemblages with the increase of altitude resemble trends
Fig. 1. Similarity of Collembolan assemblages in various communities upon the Putorana plateau: d1, d2, d3 – Dryas associations on altitudes 600, 700 and 900 m; m1, m2 – frost-boil tundra on 600 and 800 m; p1, p2 – nival deserts on 750 and 900 m; b – sedge-moss bog (600 m); based on Czekanovski-Dice-Sorensen index in a form b for quantitative data (BIODIV program).
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Table 2. Species composition and abundance (%) of Collembola in analogues plant communities of Putorana plateau (July, 1996) and Severnaya Zemlya archipelago (August, 1997) Nival desert (Plateau Putorana) 750 m alt. 900 m alt. *Protaphorura furcifera (Börner) 0.09 *Protaphorura borealis (Martynova) 10.22 *Hymenaphorura sp. 11.07 Wankeliella mediochaeta Rusek 0.68 *Anurida alpina Agrell 0.85 Hypogastrura cf. brevisensillata Yosii 7.50 *Proisotoma ananevae Babenko & Bulavintsev 17.89 Proisotoma sp.n. 8.01 Pachyotoma sp.n. 7.92 *Folsomia quadrioculata (Tullberg) – *Folsomia sp.n. [= F. diplophthalma auct.] 0.09 Folsomia sp. aff. altamontana Yosii 1.19 *Isotoma (Desoria) violacea Tullberg 25.21 *Isotoma (Isotoma) sp.n. 0.09 *Corynothryx borealis Tullberg 0.09 *Sminthurides malmgreni (Tullberg) 3.24 *Sminthurides parvulus (Krausbauer) – Sminthurides sp.n. 2.56 *Megalothorax minimus Willem 3.32 Oligaphorura groenlandica (Tullberg) – **Anurida polaris (Hammer) – Bonetogastrura nivalis (Martynova) – **Hypogastrura tullbergi (Schäffer) – **Hypogastrura trybomi (Schött) – Hypogastrura sensilis (Folsom) – Hypogastrura longispina (Tullberg) – Folsomia binoculata (Walgren) – Folsomia taimyrica Martynova – **Vertagopus pallidus Martynova – Vertagopus brevicaudus (Carpentar) – **Agrenia bidenticulata Tullberg – Number of species 17 Density (ind./dm2) 312.0 Shannon’s index (H’) 2.2 Simpson’s index (1/D) 7.15 * species, widespread in the tundra zone;
Zonal polar desert (Severnaya Zemlya) site 1 site 2
0.16 0.74 20.11 – 0.08 0.08
– – – – – –
– – – – – –
– – – 0.08 – 64.53 12.73 – 0.08 0.33 0.08 0.16 0.82 – – – – – – – – – – – – 13 325.3 1.01 2.12
– – – – – – – – – – – – – 2.87 1.13 – 3.16 0.55 0.73 2.35 60.91 16.02 7.95 3.72 0.60 11 1792.0 1.45 2.60
– – – – – – – – – – – – – 5.78 0.41 0.09 5.60 1.09 0.77 0.53 64.50 9.75 7.00 3.58 0.91 12 2437.3 1.36 2.32
** species found also upon the plateau
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Fig. 2. Distribution of species density in three Collembolan assemblages of the different climatic zones. y – axis: % of species with a given density; x-axis: density (upper limits)
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seen in latitudinal transects of the tundra (Ananjeva et al. 1987). Moving up the altitude gradient some boreal species disappear and the role of typical arctic forms increases. There is also a gradual impoverishment of the fauna due to disappearance of representatives of some apomorphic groups of Collembola, such as Entomobryidae, Tomoceridae, Bourletiellidae, Sminthuridae. These families are well represented in the forest belt of the plateau but practically disappear above the shrub belt. As a result, Collembolan assemblages of the mountainous tundras upon the plateau are not identical to the tundra ones but do have many features in common. Collembolan assemblages developed in the most severe conditions of nival desert upon the plateau have been studied on two different altitudes. These two altitude variants show very similar species make-up but have different dominants. On the upper terrace (alt. 900 m) Folsomia sp. aff. altamontana predominates. It comprises more than 60% of the total density. Few specimens of this species were previously found in the High Arctic (Severnaya Zemlya and Novosibirsk Islands), but not in a zonal community. The population is strongly clumped with Collembola restricted to plant tussocks while bare ground is almost unpopulated. The Collembolan assemblage on the lower terrace (alt. 750 m) is rather similar to those seen under snowbed vegetation in the tundra zone. Among the dominant species are both Arctic (Hymenaphorura sp. Protaphorura borealis, Proisotoma ananevae, I. violacea) and boreal mountain species (Proisotoma sp.n.), which has been also registered in alpine zone of Altai Mts. (2500–3000 m alt.). In spite of these differences collembolan assemblages of nival communities form a separate cluster in the ordination diagram (Fig. 1) far from those in the tundra-like communities of the plateau. The studied Collembola assemblages of nival Subarctic communities are also unlike to the complexes seen in the true polar desert of Severnaya Zemlya. First, they have no species in common (Table 2). It should be noted that a number of high Arctic species has been recorded upon the plateau. However they are not found in similar plant communities but rather occur either in extremely wet biotopes (A. polaris, H. trybomi, A. bidenticulata) or on moss-lichen covered cliffs (V. pallidus, H. tullbergi). The second major difference is relative abundance. Collembola are not so numerous in the nival Subarctic as in the true polar desert being less abundant and diverse than mites. The only features that Collembola assemblages of nival Subarctic communities and those of true polar desert have in common are species richness and density distribution (Fig. 2). This statement is also confirmed by similar values of dominance structure (Simpson’s index) and of biodiversity (Shannon’s index) (Table 2).
Discussion Local faunas of the Putorana plateau and the Severnaya Zemlya are very individual. Therefore, certain distinctions in Collembola species composition under similar vegetation cover should exist; however, the complete absence of common Collembola species in analogous plant communities on the Severnaya Zemlya and on the Putorana plateau was unexpected. Why do High Arctic species seen upon the plateau not occur in nival desert? The climatic conditions of the areas studied are obviously not identical. Summer
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temperatures of the plateau even on high altitude are much higher than in the Archipelago. There are some differences in moisture regime of the soils. A mosaic of plant communities is found upon the plateau due to the differences in the growing season and local peculiarities of snow accumulation and melting even more than variance of altitude. The observed distinctions in Collembola assemblages can possibly be explained by the fact that soil animals are more sensitive to soil and climatic conditions than plant assemblages. It is also possible that these differences are associated with certain peculiarities of trophic relations. A characteristic feature of saprophilous complex of the polar desert including Collembola is algiphagy – feeding on soil algae (Chernov et al. 1977). Most of the ground (from 60 to 95 %) on Severnaya Zemlya is devoid of macrophyte cover and has a algae-moss-lichen crust consisting mainly of the liverwort Gymnomitrion corallioides Ness. Collembola feed intensively on the surface of this crust. This permanent component of the true polar desert ecosystems does not develop upon the plateau. Another interesting question is the reason of structural similarity of the studied assemblages, in other words whether it is just casual that comparing assemblages involve in the same number of Collembolan species sharing the total density in a similar way. I believe it is natural and probably is an evidence of the same number of ecological niches which are available to Collembola in similar plant association of nival and zonal polar deserts. If it is true, the observed similarity should be considered as a manifestation of ecological vicariation, i.e. development of communities with the same structure on different faunistic backgrounds.
Acknowledgments I would like to express my gratitude to the organizers of the Vth International Seminar on Apterygota and personally to Dr. Miguel Gaju Ricart whose kindness and financial support made possible for me to take part in this meeting. I am also much indebted to the acarologist Dr. O. Makarova (Moscow) for the use of her material from the Severnaya Zemlya archipelago, as well as to the anonymous reviewers for their useful remarks. This paper has been financially supported by the Russian Foundation for Basic Research of the Russian Academy of Sciences (projects no. 96-04-51080 & 96-04-51081) and the program “Biological Diversity”, GNTP.
References Ananjeva, S.I., Babenko, A.B., Chernov, Yu.I. (1987) Collembola in Arctic tundras of Taimyr Zoologicheskii Zhurnal 66, 1032–1044. [in Russian] Babenko, A.B., Bulavintsev, V.I. (1997) Springtails (Collembola) of Eurasian polar desert. Russian Journal of Zoology 1, 2, 177–184. Baev, P.V., Penev, L.D. (1995) BIODIV, a program for calculating biological diversity parameters, similarity, niche overlap, and cluster analysis. Version 5.1. PenSoft, Sofia. Chernov, Yu. I. (1975) Natural zonation and terrestrial animal kingdom. Mysl, Moscow. [in Russian] Chernov, Yu.I., Striganova, B.R., Ananjeva, S.I. (1977) Soil fauna of the polar desert at cape Chelyuskin, Taimyr peninsula, USSR. Oikos 29, 175–179.
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Chernov, Yu. I., Matveyeva, N.V. (1997) Arctic ecosystems in Russia. In: Wielgolaski, F.E. (ed.) Ecosystems of the World. 3. Polar and Alpine Tundra. Elsevier, Amsterdam. Matveyeva, N.V. (1994) Floristic classification and ecology of tundra vegetation of the Taimyr Peninsula, northern Siberia. Journal of Vegetation Science 5, 813–838. Matveyeva, N.V. (1998) Zonation in plant cover of the Arctic. Nauka, St.-Petersburg. [in Russian] Walter, H., Breckle, S.-W. (1989) Ecological Systems of the Geobiosphere. 3. Temperate and Polar Zonobiomes of Northern Eurasia. Springer-Verlag, Berlin.
PROCEEDINGS OF VTH INTERNATIONAL SEMINAR ON APTERYGOTA, CORDOBA 1998
Collembolan assemblages of polar deserts and subarctic nival communities Anatoly Babenko Severtsov Institute of Ecology & Evolution, Russian Academy of Sciences Moscow 117071, Leninski pr., 33, Russia Accepted: 12. October 1999
Summary Collembolan assemblages were studied in two different regions of the Arctic, on the Severnaya Zemlya Archipelago and upon the Putorana plateau (Southern Taimyr). The comparison of assemblages, developed in similar plant associations of the polar desert zone and of nival belt of Subarctic mountains, revealed that there are no common features in their species composition even though their structures were similar. This fact could be considered as an additional argument of the biota uniqueness of the polar desert. Keywords: Collembola, population structure, zonal and extrazonal polar deserts
Introduction According to zonal typology accepted in Russia (see, for instance, Chernov 1975), treeless territories of the Subarctic1 mountains (so called ‘alpine tundra’) should be regarded as extrazonal landscapes, i.e. an analogue of a zonal community formed out of zone boundaries. It is well known that both the species composition and the structure of plant cover there and in the true tundra are similar (for review see Walter & Breckle 1989). Does this similarity include other components of the ecosystem, such as the soil invertebrates?
1 this term is used here in its English version, i.e. to the south of the Arctic. In Russian scientific papers this territory is usually called Hypoarctic whilst Subarctic means southern part of the Arctic (= Low Arctic of the western authors) (for additional explanations see Chernov & Matveyeva, 1997)
0031–4056/00/44/03–04–421 $ 12.00/0
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The present study on Collembola as one of the invertebrate groups of major importance in Arctic soils should answer this question.
Materials and Methods In 1996–1997 soil microarthropods were studied in the western part of the Putorana plateau (Dynkengda Mt., surroundings of Yt-kyuel lake, 69° 09’N 91°52’E) on the altitude transect from 600 to 1000 m above sea level. This region is situated within the northern taiga (about 100 km southward of the latitudinal timberline), but on the studied altitudes tundra-like plant associations do exist. Sampling was carried out in four main types of vegetation. Three of them are analogous to tundra communities, viz. frost-boil Dryas-sedge-moss tundra (association Carici arctisibiricae – Hylocomietum alaskani), Dryas cover on stony outcrops (association Rhytidio rugosi – Dryadetum punctatae), and sedge-moss bog (association Meesio triquetris – Caricetum stantis). The fourth is the most similar to the polar desert communities. Below only some results of this study, devoted to Collembolan assemblages of the latter vegetation type, will be described and discussed. These plant associations develop above 700 m in the places where snow cover remains over a long period of time. Vegetation cover of these sites is similar to the typical zonal associations of the polar desert having identical community structure and many plant species in common including vascular plants, mosses and lichens, but considerably poorer. Floristically these nival deserts are also comparable with snowbed communities of the tundra zone, namely with the association Deschamsio-Cerastietum regelii. Detailed floristic descriptions of all these plant associations can be found in Matveyeva’s papers (1994, 1998). The data on Collembola from the true polar desert is based on a new material collected in 1997–1998 by Dr. O. Makarova in zonal polar desert communities of Bol’shevik Island (Severnaya Zemlya archipelago, 78° 11’N 103° 15’E). The following results are based on the analysis of more than 400 soil samples (25 cm2, depth 5 cm). In each of studied plant associations samples were taken according to the existing vegetation mosaic to obtain the most representative estimation for the whole habitat. Statistical procedures were performed by the program BIODIV 5.1 (Baev & Penev 1995) and the standard Statistical program for Windows.
Results Thirty two Collembola species have been recorded from Severnaya Zemlya (Babenko & Bulavintsev 1987; unpublished material of 1987–1988). About ten of them are found in practically all plant associations existing there (Table 1) and these very species constitute most of the polar desert fauna throughout the Palaearctic. All the other species known from the archipelago localized usually in the warmest biotopes and were not abundant even there. Among these “southern” species there are some widespread and polyzonal forms (for instance, Megalothorax minimus, Jeannenotia stachi (Jeannenot), Pseudanurophorus alticolus, and Willemia scandinavica), but the most of the Collembola of the Severnaya Zemlya are typical High-Arctic forms. As a rule, their distribution is not restricted to the polar desert (Vertagopus brevicaudus is an exception) and they are often found in communities of the tundra zone and southwards only in mountains. The most striking feature of collembolan assemblages of the polar desert is their abundance (Table 1). They exceed not only the abundance of all other groups of soil
Bog
– 1.04 1.86 0.02 64.64 5.80 1.35 1.65 0.88 1.90 0.49 20.20 0.19 – – – – – – – – – – 12 1568.6
– 0.77 5.78 5.60 64.50 7.00 3.58 0.91 1.09 0.53 0.41 9.75 0.09 – – – – – – – – – – 12 2437.3
Zonal Snow-bed community
species marked in bold are the most typical for the Palaearctic polar desert
Isotoma tschernovi Martynova 0.94 Hypogastrura sensilis (Folsom) 0.39 Oligaphorura groenlandica (Tullberg) 3.07 Hypogastrura tullbergi (Schäffer) 1.68 Folsomia binoculata (Walgren) [= F. regularis auct.] 68.81 Vertagopus pallidus Martynova 23.13 Vertagopus brevicaudus (Carpenter) 0.19 Agrenia bidenticulata Tullberg 0.36 Hypogastrura trybomi (Schött) 0.49 Hypogastrura longispina (Tullberg) 0.81 Anurida polaris (Hammer) 0.13 Folsomia taimyrica Martynova – Bonetogastrura nivalis (Martynova) – Megalothorax minimus (Willem) – Anurida alpina Agrell – Stenacidia sp. – Corynothryx borealis Tullberg – Pseudanurophorus alticolus Bagnall – Willemia similis Mills – Willemia scandinavica Stach – Protaphorura pjasinae (Martynova) – Hypogastrura concolor (Carpenter) – Folsomia alpha Grow & Christiansen – Number of species 11 Density (ind./dm2) 1374.1
Species/Biotopes
6.32 1.12 0.29 88.63 0.80 1.19 – 0.34 0.09 – – – – – – – – – – 11 5501.1
– 1.03 0.11 0.05 75.51 12.49 0.35 0.06 0.16 0.03 – 2.91 – 3.91 0.48 0.06 – – – – – – – 12 2498,2
– – 2.98 1.06 46.69 28.44 0.72 0.03 – – 2.69 3.01 2.72 1.82 0.09 – 0.03 1.16 0.06 – – – – 14 1383,5
– – 2.75 9.81
47.78 6.78 0.16 0.56 0.09 0.26 1.89 17.12 0.74 0.20 – – 0.01 0.13 0.06 0.01 0.04 3.65 0.20 19 1719,9
– – 16.76 3.55
Stream Patches of Rhacomitrium Lemming bank Carex ensifolia lanuginosum nests arctisibirica mat
Table 1. Species composition and abundance (%) of Collembola in the main plant association on the Severnaya Zemlya archipelago (August, 1997)
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microarthropods there but Collembola abundance both in the tundra zone and more southern forest habitats as well. Collembolan assemblages developed there include only one dominant species (Fig. 2) and its density usually comprises more than a half of total population. Extreme polytopy of the majority of Collembolan species is characteristic of the polar desert zone. Due to this polytopy, changes in relative densities of certain species but not in species composition do exist from site to site. Another typical feature of spatial distribution of Collembola in the polar desert is that many species which prefer extremely wet sites in the tundra (Hypogastrura spp., Agrenia bidenticulata, Folsomia binoculata, Anurida polaris, etc. ) inhabit there zonal plain communities. Fauna of the studied part of the Putorana plateau is mainly boreal and more diverse (no less than 100 species have been recorded). 53 species have been found regularly above the timberline upon the plateau. Among them there are widespread, polyzonal and boreal forms. Some typical High-Arctic species, for example, A. bidenticulata, Hypogastrura trybomi, H. tullbergi, Vertagopus pallidus, Anurida polaris, Isotoma violacea have been also found. These true Arctic forms are not numerous in any of the studied biotopes, except for the nival ones where I. violacea is one of the dominants. Changes in Collembola assemblages with the increase of altitude resemble trends
Fig. 1. Similarity of Collembolan assemblages in various communities upon the Putorana plateau: d1, d2, d3 – Dryas associations on altitudes 600, 700 and 900 m; m1, m2 – frost-boil tundra on 600 and 800 m; p1, p2 – nival deserts on 750 and 900 m; b – sedge-moss bog (600 m); based on Czekanovski-Dice-Sorensen index in a form b for quantitative data (BIODIV program).
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Table 2. Species composition and abundance (%) of Collembola in analogues plant communities of Putorana plateau (July, 1996) and Severnaya Zemlya archipelago (August, 1997) Nival desert (Plateau Putorana) 750 m alt. 900 m alt. *Protaphorura furcifera (Börner) 0.09 *Protaphorura borealis (Martynova) 10.22 *Hymenaphorura sp. 11.07 Wankeliella mediochaeta Rusek 0.68 *Anurida alpina Agrell 0.85 Hypogastrura cf. brevisensillata Yosii 7.50 *Proisotoma ananevae Babenko & Bulavintsev 17.89 Proisotoma sp.n. 8.01 Pachyotoma sp.n. 7.92 *Folsomia quadrioculata (Tullberg) – *Folsomia sp.n. [= F. diplophthalma auct.] 0.09 Folsomia sp. aff. altamontana Yosii 1.19 *Isotoma (Desoria) violacea Tullberg 25.21 *Isotoma (Isotoma) sp.n. 0.09 *Corynothryx borealis Tullberg 0.09 *Sminthurides malmgreni (Tullberg) 3.24 *Sminthurides parvulus (Krausbauer) – Sminthurides sp.n. 2.56 *Megalothorax minimus Willem 3.32 Oligaphorura groenlandica (Tullberg) – **Anurida polaris (Hammer) – Bonetogastrura nivalis (Martynova) – **Hypogastrura tullbergi (Schäffer) – **Hypogastrura trybomi (Schött) – Hypogastrura sensilis (Folsom) – Hypogastrura longispina (Tullberg) – Folsomia binoculata (Walgren) – Folsomia taimyrica Martynova – **Vertagopus pallidus Martynova – Vertagopus brevicaudus (Carpentar) – **Agrenia bidenticulata Tullberg – Number of species 17 Density (ind./dm2) 312.0 Shannon’s index (H’) 2.2 Simpson’s index (1/D) 7.15 * species, widespread in the tundra zone;
Zonal polar desert (Severnaya Zemlya) site 1 site 2
0.16 0.74 20.11 – 0.08 0.08
– – – – – –
– – – – – –
– – – 0.08 – 64.53 12.73 – 0.08 0.33 0.08 0.16 0.82 – – – – – – – – – – – – 13 325.3 1.01 2.12
– – – – – – – – – – – – – 2.87 1.13 – 3.16 0.55 0.73 2.35 60.91 16.02 7.95 3.72 0.60 11 1792.0 1.45 2.60
– – – – – – – – – – – – – 5.78 0.41 0.09 5.60 1.09 0.77 0.53 64.50 9.75 7.00 3.58 0.91 12 2437.3 1.36 2.32
** species found also upon the plateau
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Fig. 2. Distribution of species density in three Collembolan assemblages of the different climatic zones. y – axis: % of species with a given density; x-axis: density (upper limits)
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seen in latitudinal transects of the tundra (Ananjeva et al. 1987). Moving up the altitude gradient some boreal species disappear and the role of typical arctic forms increases. There is also a gradual impoverishment of the fauna due to disappearance of representatives of some apomorphic groups of Collembola, such as Entomobryidae, Tomoceridae, Bourletiellidae, Sminthuridae. These families are well represented in the forest belt of the plateau but practically disappear above the shrub belt. As a result, Collembolan assemblages of the mountainous tundras upon the plateau are not identical to the tundra ones but do have many features in common. Collembolan assemblages developed in the most severe conditions of nival desert upon the plateau have been studied on two different altitudes. These two altitude variants show very similar species make-up but have different dominants. On the upper terrace (alt. 900 m) Folsomia sp. aff. altamontana predominates. It comprises more than 60% of the total density. Few specimens of this species were previously found in the High Arctic (Severnaya Zemlya and Novosibirsk Islands), but not in a zonal community. The population is strongly clumped with Collembola restricted to plant tussocks while bare ground is almost unpopulated. The Collembolan assemblage on the lower terrace (alt. 750 m) is rather similar to those seen under snowbed vegetation in the tundra zone. Among the dominant species are both Arctic (Hymenaphorura sp. Protaphorura borealis, Proisotoma ananevae, I. violacea) and boreal mountain species (Proisotoma sp.n.), which has been also registered in alpine zone of Altai Mts. (2500–3000 m alt.). In spite of these differences collembolan assemblages of nival communities form a separate cluster in the ordination diagram (Fig. 1) far from those in the tundra-like communities of the plateau. The studied Collembola assemblages of nival Subarctic communities are also unlike to the complexes seen in the true polar desert of Severnaya Zemlya. First, they have no species in common (Table 2). It should be noted that a number of high Arctic species has been recorded upon the plateau. However they are not found in similar plant communities but rather occur either in extremely wet biotopes (A. polaris, H. trybomi, A. bidenticulata) or on moss-lichen covered cliffs (V. pallidus, H. tullbergi). The second major difference is relative abundance. Collembola are not so numerous in the nival Subarctic as in the true polar desert being less abundant and diverse than mites. The only features that Collembola assemblages of nival Subarctic communities and those of true polar desert have in common are species richness and density distribution (Fig. 2). This statement is also confirmed by similar values of dominance structure (Simpson’s index) and of biodiversity (Shannon’s index) (Table 2).
Discussion Local faunas of the Putorana plateau and the Severnaya Zemlya are very individual. Therefore, certain distinctions in Collembola species composition under similar vegetation cover should exist; however, the complete absence of common Collembola species in analogous plant communities on the Severnaya Zemlya and on the Putorana plateau was unexpected. Why do High Arctic species seen upon the plateau not occur in nival desert? The climatic conditions of the areas studied are obviously not identical. Summer
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temperatures of the plateau even on high altitude are much higher than in the Archipelago. There are some differences in moisture regime of the soils. A mosaic of plant communities is found upon the plateau due to the differences in the growing season and local peculiarities of snow accumulation and melting even more than variance of altitude. The observed distinctions in Collembola assemblages can possibly be explained by the fact that soil animals are more sensitive to soil and climatic conditions than plant assemblages. It is also possible that these differences are associated with certain peculiarities of trophic relations. A characteristic feature of saprophilous complex of the polar desert including Collembola is algiphagy – feeding on soil algae (Chernov et al. 1977). Most of the ground (from 60 to 95 %) on Severnaya Zemlya is devoid of macrophyte cover and has a algae-moss-lichen crust consisting mainly of the liverwort Gymnomitrion corallioides Ness. Collembola feed intensively on the surface of this crust. This permanent component of the true polar desert ecosystems does not develop upon the plateau. Another interesting question is the reason of structural similarity of the studied assemblages, in other words whether it is just casual that comparing assemblages involve in the same number of Collembolan species sharing the total density in a similar way. I believe it is natural and probably is an evidence of the same number of ecological niches which are available to Collembola in similar plant association of nival and zonal polar deserts. If it is true, the observed similarity should be considered as a manifestation of ecological vicariation, i.e. development of communities with the same structure on different faunistic backgrounds.
Acknowledgments I would like to express my gratitude to the organizers of the Vth International Seminar on Apterygota and personally to Dr. Miguel Gaju Ricart whose kindness and financial support made possible for me to take part in this meeting. I am also much indebted to the acarologist Dr. O. Makarova (Moscow) for the use of her material from the Severnaya Zemlya archipelago, as well as to the anonymous reviewers for their useful remarks. This paper has been financially supported by the Russian Foundation for Basic Research of the Russian Academy of Sciences (projects no. 96-04-51080 & 96-04-51081) and the program “Biological Diversity”, GNTP.
References Ananjeva, S.I., Babenko, A.B., Chernov, Yu.I. (1987) Collembola in Arctic tundras of Taimyr Zoologicheskii Zhurnal 66, 1032–1044. [in Russian] Babenko, A.B., Bulavintsev, V.I. (1997) Springtails (Collembola) of Eurasian polar desert. Russian Journal of Zoology 1, 2, 177–184. Baev, P.V., Penev, L.D. (1995) BIODIV, a program for calculating biological diversity parameters, similarity, niche overlap, and cluster analysis. Version 5.1. PenSoft, Sofia. Chernov, Yu. I. (1975) Natural zonation and terrestrial animal kingdom. Mysl, Moscow. [in Russian] Chernov, Yu.I., Striganova, B.R., Ananjeva, S.I. (1977) Soil fauna of the polar desert at cape Chelyuskin, Taimyr peninsula, USSR. Oikos 29, 175–179.
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Chernov, Yu. I., Matveyeva, N.V. (1997) Arctic ecosystems in Russia. In: Wielgolaski, F.E. (ed.) Ecosystems of the World. 3. Polar and Alpine Tundra. Elsevier, Amsterdam. Matveyeva, N.V. (1994) Floristic classification and ecology of tundra vegetation of the Taimyr Peninsula, northern Siberia. Journal of Vegetation Science 5, 813–838. Matveyeva, N.V. (1998) Zonation in plant cover of the Arctic. Nauka, St.-Petersburg. [in Russian] Walter, H., Breckle, S.-W. (1989) Ecological Systems of the Geobiosphere. 3. Temperate and Polar Zonobiomes of Northern Eurasia. Springer-Verlag, Berlin.