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Vegetation Dynamics of Mongolia

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Geobotany 26

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The titles published in this series are listed at the end o/this volume.

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1%5 1970 1975 1980

_.-.i I -' . .. _ .. _ .. 1'.
\ 5

1985 1990

Figure 3.24. Changes in main species coverage
in the community Stipa glareosa, S. gobica +
Cleistogenes squarrosa + Artemisiafrigida

during 1970 - 1990 due to grazing
intensification (according to observations of

the Bulgan station).
I - 6. Main species and groups of species: 1 - Stipa
glareosa, s. gobica. 2 - Cleistogenes squarrosa. 3 -
Caragana leucophloea, Krascheninnikovia ceratoides. 4
- Artemisia frigida. 5 - Allium polyrrhzum, Gypsophila
desertorum. 6 - annual and biennial semi-weeds (Aristida
heymannii, Eragrostis minor, Corispermum mongoticum,
Convolvulus ammanii, Salsola coltina, Bassia dasyphylla,
Euphorbia humifusa).

Normally groups of Leymus chinensis,
Artemisia scoparia and Linaria acutiloba
dominated. This first regeneration stage of
steppe tall-weed vegetation was recorded for
about seven years. In the seventh year typical
steppe species appear on the original fallow:
Agropyron cristatum, Cleistogenes squarrosa
and feathergrasses (Stipa krylovii, S. sibirica).
Although a high abundance of typical «fallow»
species remain (Artemisia scoparia, Axyris
amaranthoides, Linaria acutiloba). Together
these indicate a second stage in the regenera-
tion of steppe vegetation (Figure 3.25). Finally

only 18- and 22-year-old fallows show a grass
stand dominance of dense-sod grasses (Stipa
sibirica and S. krylovii). Although Artemisia
scoparia, Linaria acutiloba and other typically
«fallow» species do occur frequently
(Miklyaeva, 1996; Hilbig, 1988).

But such a gradual regeneration of steppe
vegetation frequently is disturbed by repeated
ploughing, or is greatly handicapped by heavy
pastoral pressure (Gunin et aI., 1996). Such
secondary ploughing was observed in 1996 on
a large mass of ploughed land near the Orkhon
and Khara-Gol rivers. In addition to field
weeds, such ploughlands have an abundance of
grazing pressure indicator species Potentilla
tanacetifolia, P. bifurca, Carum carvi,
Artemisia scoparia and Thermopsis lanceolata.
The vegetation dynamics of fallow lands was
studied by O.A. Klimanova.

The sharpest changes in ecological habitat
conditions and successions of plant
communities occur as a result of irrigated
arable farming. Normally, irrigated plots are
small 3 to 10 ha. Irrigation involves either
surface or water table water. Arable farming
sharply affects vegetation on plots adjacent to
the cropland. Due to artificially increased
moisture, such plots have a sharp replacement
of primary plant communities by secondary
ruderal and hydromorphic species.

For instance, in the Obot-Khural region of
Alashan Gobi, the irrigated croplands of the
Khurshut farm account for an area of 10 ha on
a high terrace and a gentle low mountain slope.
Spring irrigation waters peter out along a
tectonic disturbance (Vostokova et al., 1993,
1994). On non-irrigated plots formed by loam
with rock debris, the vegetation is sparse
communities of Reaumuria songarica, Salsola
passerina and Anabasis brevifolia;
occasionally with Limonium tenellum, Ajania
fruticulosa and Stipa glareosa. This vegetation
on the edge of individual vegetable croplands
was replaced by patches of weed hydromorphic
group of Malva sylvestris, Atriplex tatarica,
Convolvulus chinensis, Lactuca tatarica,
Peganum nigellastrum, lnula britannica,
Sonchus arvensis and Polygonum arenastrum.

Page 122



O~ ' .. 3: c
o 0


3 D 0

~1 ~11

82 I±::±] 12
0 . • J ~IJ
~4 E314

E:!Is E2]IS
~6 1+.+1"116

1-~3 7 E!117

E3s ~18
I---J 9 1ft- *119
1/ .. 1',110 1=-.-1 20

On plot margins a better-formed community
developed of Achnatherum splendens, where
Sphaerophysa salsula and Phragmites australis
are fairly abundant. But where water flow and
croplands is not so great, processes of
secondary salinization and halohydromorphic
communities are established such as deris
community replacements by shrubs of Tamarix
hispida, T. ramosissima with Kalidium

Similar successions of desert and dry-
steppe plant communities by halohydromor-
phic communities are observed commonly at
sites of water seepage from irrigated croplands.

Figure 3.25. The structure of idle dry steppes
lands near the Tumentsogt station

(Miklyaeva, 1996).

The structure of idle lands: a - one year, b - 7 years, c -
22 - years. 1-20. Plant communities with predominance
of: I - Leymus chinensis, 2 - Linaria acutiloba, 3 -
Artemisia scoparia, 4 - Artemisia scoparia +
Aconogonon divaricatum, 5 - Artemisia scoparia + Poa
attenuata subsp. botryoides, 6 - Artemisia scoparia,
A. jrigida, 7 - Artemisia scoparia, A. palustris, 8 -
Artemisia macrocephala, 9 - Stipa sibirica + Axyris
amaranthoides, 10 - Stipa sibirica + Artemisia scoparia,
11 - Stipa sibirica + Thermopsis lanceolata, 12 - Stipa
sibirica + Artemisia dracunculus, 13 - Stipa sibirica, Poa
attenuata subsp. botryoides, 14 - Stipa sibirica, 15 - Poa
attenuata subsp. botryoides, 16 - Salsola monoptera, 17-
18. At inhabited fossorial animal colonies: 17 - Salsola
monoptera + Artemisia scoparia, 18 - Axyris
amaranthoides. 19-20. At abandoned fossorial animal
colonies: 19 - Artemisia palustris, A. jrigida, 20 - Stipa
sibirica + Salsola monoptera.

For instance, in the Dariganga region
(southeastern Mongolia) the community
Reaumuria songarica + Salsola laricifolia +
Anabasis brevifolia is replaced by group with
Salsola collina, S. tragus and Saussurea

When abandoned croplands are no longer
irrigated, they are populated by xeromorphic
weeds and wormwoods (Artemisia anethoides,
A. annua), and after 10 to 20 years an almost
original desert communities recovers. Thus, a
sharp change in moisture conditions fairly
rapidly results in a replacement of primary
desert vegetation by hydromorphic and
halohydromorphic. However, regeneration
successions on originally non-irrigated crop-
lands proceed very slowly.

In summary, a variety of observations show
that modern dynamics of vegetation on steppe
and desert plains and hummocky topography
areas follow a regression pattern. Successions
of plant communites result in the formation of
less productive communities with a xerophyte
dominances that are impoverished in terms of
species composition. When the human-
related pressures are removed, regeneration
successions proceed at a fairly slow rate over
about 20 years.

Page 242


1. J.B. Hall and M.D. Swaine (eds.): Distribution and Ecology of Vascular Plants in a
Tropical Rain Forest. Forest Vegetation in Ghana. 1981 ISBN 90-6193-681-0

2. W. Holzner and M. Numata (eds.): Biology and Ecology of Weeds. 1982
ISBN 90-6193-682-9

3. N.J.M. Gremmen: The Vegetation of the Subantarctic Islands Marion and Prince
Edward. 1982 ISBN 90-6193-683-7

4. R.c. Buckley (ed.): Ant-Plant Interactions in Australia. 1982 ISBN 90-6193-684-5
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ISBN 90-6193-685-3

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Flats, Zambia. 1987 ISBN 90-6193-638-1

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Causes, Effects and Processes. 1987 ISBN 90-6193-640-3

II. A.H.L. Huiskes, C. W.P.M. Blom and J. Rozema (eds.): Vegetation Between Land and
Sea. Structure and Processes. 1987 ISBN 90-6193-649-7

12. G. Orshan (ed.): Plant Pheno-morphological Studies in Mediterranean Type Ecosys-
tems. 1988 ISBN 90-6193-656-X

13. B. Dell, J.J. Havel and N. Malajczuk (eds.): The Jarrah Forest. A Complex Mediter-
ranean Ecosystem. 1988 ISBN 90-6193-658-6

14. J.P. Bakker: Nature Management by Grazing and Cutting. 1989 ISBN 0-7923-0068-8

15. J. Osbornovli, M. Kovarovli, J. Leps and K. Prach (eds.): Succession in Abandoned
Fields. Studies in Central Bohemia, Czechoslovakia. 1990 ISBN 0-7923-0401-2

16. B. Gopal (ed.): Ecology and Management of Aquatic Vegetation in the Indian Sub-
continent. 1990 ISBN 0-7923-0666-X

17. B.A. Roberts and J. Proctor (eds.): The Ecology of Areas with Serpentinized Rocks.
A World View. 1991. ISBN 0-7923-0922-7

18. J.T.A. Verhoeven (ed.): Fens and Bogs in the Netherlands. Vegetation, History, Nutri-
ent Dynamics and Conservation. 1992 ISBN 0-7923-1387-9

19. Woo-seok Kong and D. Watts: The Plant Geography of Korea. With an Emphasis on
the Alpine Zones. 1993 ISBN 0-7923-2068-9

Page 243


20. R. Aerts and G.W. Heil (eds.): Heathlands. Patterns and Processes in a Changing
Environment. 1993 ISBN 0-7923-2094-8

21. W. van Vierssen, M. Hootsmans and J. Vermaat (eds.): Lake VeJuwe, a Macrophyte-
dominated System under Eutrophication Stress. 1994 ISBN 0-7923-2320-3

22. Y. Laumonier: The Vegetation and Physiography of Sumatra. 1997
ISBN 0-7923-3761-1

23. C.M. Finlayson and I. von Oertzen (eds.): Landscape and Vegetation Ecology of the
Kakadu Region, Northern Australia. 1996 ISBN 0-7923-3770-0

24. R. Peters: Beech Forests. 1997 ISBN 0-7923-4485-5

25. S .A. Ghazanfar and M. Fisher (eds.): Vegetation of the Arabian Peninsula. 1999
ISBN 0-7923-5015-4

26. P.D. Gunin, E.A. Vostokova, N.I. Dorofeyuk, P.E. Tarasov and C.C. Black (eds.):
Vegetation Dynamics of Mongolia. 1999 ISBN 7923-5582-2


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