On nomenclatural problems of syntaxonomy of Siberian steppes, diversity and some general vegetation features of Chuya depression (Republic of Altai)
Authors: Korolyuk A. Yu. , Namzalov B. B. 
Published: December 2024

Chuya depression is a unique enclave of Central Asian desert steppes. Based on the analysis of more than 700 relevés, we describe the diversity of the halophyte and steppe communities.

Class Therosalicornietea Tx. in Tx. et Oberd. 1958 is represented by the ass. Suaedetum corniculatae Burtzeva in Mirkin et al. 1992 (Table 1, rel. 1–3; Fig. 4) and comm. Salicornia altaica (Table 1, rel. 4; Fig. 5).

Class Kalidietea foliati Mirkin et al. ex Rukhlenko 2012 includes communities that occupy habitats with mineralized waters coming to the surface (Fig. 6) — ass. Reaumurio songaricae–Kalidietum foliati ass. nov. (Table 1, rel. 5–7), holotypus — Table 1, rel. 6 (field no. 22–432), Republic of Altai, Kosh-Agach district, SSE of the Kosh-Agach village, SW from the Misheldyk mountain, flat depression, 49.88236° N, 88.79077° E, 19.08.2022, A. Yu. Korolyuk. Diagnostic species (D. s.): Kalidium foliatum (dom.), Reaumuria songarica.

Class Stipetea glareosae–gobicae Hilbig 2000 unites Central Asian desert steppes.

Ass. Reaumurio songaricae–Achnatheretum splendentis ass. nov. (Table 1, rel. 8–21), holotypus — Table 1, rel. 18 (field no. 10-666), Republic of Altai, Kosh-Agach district, SSE of the Kosh-Agach village, SW from the Misheldyk mountain, plain, 49.88649° N, 88.76022° E, 19.08.2022, A. Yu. Korolyuk. D. s.: Achnatherum splendens (dom.), Artemisia compacta, Kalidium foliatum, Reaumuria songarica (dom.), Zygophyllum melongena.Communities are widespread along the bottom of the Chuya depression on clay plains with saline soils (Fig. 7).

Ass. Stipo glareosae–Anabasietum brevifoliae Hilbig (1987) 1990 (Table 2, rel. 1–14) is widespread along the bottom of Chuya depression(Fig. 8). D. s.: Anabasis brevifolia (dom.), Stipa glareosa (dom.).

Ass. Psathyrostachyo junceae–Chenopodietum frutescentis ass. nov. (Table 2, rel. 15–27), holotypus — Table 2, rel. 26 (field no. 22-427), Republic of Altai, Kosh-Agach district, near Chegan-Uzun village, mountain ridge foot, 50.07065° N, 88.39848° E, 18.08.2022, A. Yu. Korolyuk. D. s.: Chenopodium frutescens (dom.), Psathyrostachys juncea. The communities dominated by Chenopodium frutescens occupy outcrops of variegated rocks and siltstones (Fig 9).

Ass. Stipo glareosae–Atraphaxietum pungentis ass. nov. (Table 3, rel. 1–10), holotypus — Table 3, rel. 1 (field no. 7-156), Republic of Altai, Kosh-Agach district, SW Chegan-Uzun village, convex southern slope, 50.06408° N, 88.29992° E, 10.06.2007, A. Yu. Korolyuk.

D. s.: Atraphaxis pungens, Caragana bungei, Chenopodium frutescens, Gypsophila patrinii, Panzerina canescens, Saussurea pricei, Stipa kirghisorum.

The association represents petrophytic communities that are found on convex rocky slopes in hilly land in the northwestern part of Chuya depression.

Ass. Allio vodopjanovae–Stipetum glareosae Korolyuk ex Korolyuk et Namzalov ass. nov. (Table 3, rel. 11–33), holotypus — Table 1, rel. 16 (Stepi…, 2002: стр. 231–232). Syn. Allio vodopjanovae–Stipetum glareosae Korolyuk 2002 [Art. 5]. D. s.: Allium vodopjanovae, Astragalus dilutus, Dontostemon perennis, Stipa glareosa (dom.). The association represents desert steppes that dominate in the lower western part of the depression (Fig. 10, 11).

Class Agropyretea cristati Hilbig et Korolyuk 2000 represents typical bunchgrass steppes and their petrophytic variants.

Syn.: Cleistogenetea squarrosae Mirkin et al. 1985 [ICPN, Art. 1], Cleistogenetea Mirkin, Gogoleva et Kononov 1985 [ICPN, Art. 2b, 3f, 5], Cleistogenetea squarrosae Kononov, Gogoleva et Mironova 1985 [ICPN, Art. 2b, 8], Cleistogenetea squarrosae Mirkin et al. 1986 [ICPN, Art. 1, 2b], Cleistogenetea squarrosae Mirkin et al. 1986 em. 1987 [ICPN, Art. 1], Cleistogenetea squarrosae Mirkin in Gogoleva et al. 1987 [ICPN, Art. 5], Cleistogenetea squarrosae Mirkin et al. ex Korotkov et al. 1991 [ICPN, Art. 3o, 5], Cleistogenetea squarrosae Mirkin et al. 1992 [ICPN, Art. 3f].

Order Stipetalia krylovii Mirkin in Gogoleva et al. ex Korolyuk et Namzalov ord. nov. hoc loco.

Syn.: Stipetalia krylovii Kononov, Gogoleva et Mironova 1985 [ICPN, Art. 2b, 8], Stipetalia krylovii Mirkin in Gogoleva et al. 1987 [ICPN, Art. 5], Cleistogenetalia squarrosae Mirkin et al. ex Ermakov 2012 [ICPN, Art. 3i].

Holotypus hoc loco: alliance Allio bidentati–Cleistogenion squarrosaeKorolyuk et Namzalov all. nov.

D. s. of order: Achnatherum sibiricum, Aconogonon angustifolium, Agropyron cristatum, Allium anisopodium, A. bidentatum, A. senescens, A. tenuissimum, Alyssum lenense, Artemisia commutata, A. frigida, Caragana pygmaea, Carex duriuscula, Chamaerhodos erecta, Cleistogenes squarrosa, Cymbaria daurica, Dontostemon integrifolius, Goniolimon speciosum, Heteropappus altaicus, H. biennis, Lespedeza juncea, Leymus chinensis, Poa botryoides, Polygala tenuifolia, Potentilla acaulis, P. bifurca, P. tanacetifolia, Pulsatilla turczaninovii, Saussurea salicifolia, Scorzonera austriaca, Serratula centauroides, Sibbaldianthe adpressa, Stipa grandis, S. krylovii, Teloxys aristata.

Alliance Allio bidentati–Cleistogenion squarrosaeKorolyuk et Namzalov all. nov. Holotypus hoc loco: ass. Potentillo semiglabrae–Stipetum grandis Korolyuk 2019 (Korolyuk, 2019: p. 31).

D. s.: Allium anisopodium, A. bidentatum, A. senescens, A. tenuissimum, Cymbaria daurica, Dontostemon integrifolius, Leymus chinensis, Melilotoides ruthenica, Oxytropis turczaninovii, Potentilla semiglabra, Serratula centauroides, Thalictrum squarrosum.

The alliance represents typical steppes of Transbaikalia and Eastern Mongolia.

Alliance Potentillo acaulis–Stipion kryloviiKorolyuk et Namzalov all. nov.

Holotypus hoc loco: ass. Artemisio frigidae–Stipetum krylovii Korolyuk et Makunina 2009 (Korolyuk, Makunina, 2009: p. 46).

D. s.: Agropyron cristatum, Artemisia frigida, A. obtusiloba, A. santolinifolia, Festuca valesiaca, Heteropappus altaicus, Koeleria cristata, Leymus dasystachys, Potentilla acaulis, P. bifurca, Stipa capillata, S. krylovii.

The alliance includes bunchgrass typical steppes, widespread in the mountain-steppe belt Altay-Sayan mountains and Western Mongolia.

Ass. Artemisio frigidae–Stipetum krylovii Korolyuk et Makunina 2009 (Table 4, rel. 1–23) dominates in the east of the Chuya depression (Fig. 2, 12, 13).

Ass. Artemisietum obtusilobae–santolinifoliae Korolyuk in Korolyuk et Makunina 2009 (Table 4, rel. 24–35) unites petrophytic communities along screes and rocky slopes (Fig. 2, 14). D. s.: Artemisia obtusiloba (dom.), A. santolinifolia (dom.), Oxytropis tragacanthoides, Ptilotrichum canescens.

Ass. Poo attenuatae–Festucetum tschujensis Korolyuk et Namzalov 1994 (Table 5, rel. 1–22) unites bunchgrass steppes common in the upper part of the steppe belt. D. s.: Allium rubens, Artemisia pycnorhiza, Aster alpinus, Astragalus multicaulis, Clausia aprica, Eritrichium subrupestre, Festuca tschujensis (дом.), Koeleria altaica, Oxytropis eriocarpa, Peucedanum vaginatum, Potentilla aff. jenissejensis, Stellaria petraea.

Order Kochio prostratae–Stipetalia krylovii Ermakov 2012 and alliance Kochio prostratae–Stipion krylovii Ermakov 2012 represents desert and dry steppes.

Ass. Festuco tschujensis–Stipetum glareosae Korolyuk ex Korolyuk et Namzalov ass. nov. (Table 5, rel. 23–46), holotypus — Table 6, rel. 10 (Stepi…, 2002: pp. 239–242). Syn. Festuco tschujensis–Stipetum glareosae Korolyuk 2002 [ICPN, Art. 5] represents steppes, widespread at altitudes from 2000 to 2300 m a. s. l. D. s.: Astragalus dilutus, Eritrichium subrupestre, Festuca tschujensis, Oxytropis pumila, Stipa glareosa.

The distribution of associations reflects the altitudinal structure of vegetation (Fig. 15). Communities of the class Stipetea glareosae–gobicae occupy the western lower part of Chuya depression. In the elevated eastern part and on adjacent slopes, bunchgrass steppes of the order Stipetalia krylovii dominate. The order Helictotrichetalia schelliani is presented in fragmented forest-steppe belt. Steppes are followed by the alpine class Carici rupestris–Kobresietea bellardii.

Using the species indicator values of Southern Siberia plants (Korolyuk, 2006), the associations were ordinated along the gradients of soil moisture and richness–salinity (Fig. 16).

Funded by Chinese Academy of Sciences President’s International Fellowship Initiative, Grant № 2024PVA0090.