Vegetation of sandy coasts of Lake Baikal

• Index page
•   
• Scientific activity
•   
• Periodic publications
•   
• Vegetation of Russia
•   
• Issue 29, 2016
•   
• Vegetation of sandy coasts of Lake Baikal

N. A. Dulepova

DOI: https://doi.org/10.31111/vegrus/2016.29.46

Full article

Annotation

The aeolian processes play an important role in the relief formation under the semiarid conditions of the intermountain basins of Southern Siberia. Ancient sand landforms occur in different regions of Siberia — the Ob, Chuya, Аley, Yenisei, Аngara, Selenga, Chikoy, Khilok and Chara river valleys and Lake Baikal coasts. The sandy coasts of Lake Baikal are of great interest in terms of floristic diversity determined by a high degree of endemism. Despite centuries of study of the lake basin, sand vegetation is poorly described in the literature.

This study presents an analysis of 184 relevés of psammophytic vegetation from the Republic of Buryatia (Severobaikalsky, Barguzinsky, Pribaikalsky districts) and Irkutsk region (Olkhon Island) obtained in 2009–2014.

The vegetation on coastal sands of Lake Baikal refers to the class Brometea korotkyi and order Oxytropidetalia lanatae. Three diagnostic species, Bromopsis korotkiji, Corispermum sibiricum and Carex sabulosa, are presented in the most of sand areas. The species of the order Oxytropidetalia lanatae are prominent there, including Oxytropis lanata, Artemisia ledebouriana, Chamaerhodos grandiflora, which are characterized by high constancy often being the dominants. The original authors of the alliance Oxytropidion lanatae Chytrý, Pešout et Anenchonov 1993 had difficulties in identifying the diagnostic species combinations of the syntaxa due to a small size of the study area (the Barguzin Bay). Analysis of the obtained information allows to determine the alliance diagnostic species as well as its geographic range.

The alliance Oxytropidion lanatae unites the vegetation of Lake Baikal sandy coasts and is characterized by the following species: Aconogonon ochreatum, Astragalus sericeocanus, Corispermum ulopterum, Craniospermum subvillosum, Festuca rubra subsp. baicalensis, Leymus secalinus, Phlojodicarpus sibiricus and Scrophularia incisa. It includes 8 associations, 5 subassociations and 3 communities.

The high diversity of plant communities on Lake Baikal sandy coasts is related to the environmental variability of local sandy areas as well as with the high number of endemic species. Only two associations of the alliance Oxytropidion lanatae are widespread on all sandy coasts of the lake: Oxytropido lanatae–Festucetum baicalensis and Craniospermo subvillosi–Leymetum secalini. The association Festuco baicalensis–Caricetum sabulosae occurs in the Severobaikalsky, Pribaikalsky and Olkhon districts. The associations Aconogono ochreati–Calamagrostietum epigei and Stellario dichotomae–Rosetum acicularis are characteristic of two areas  — Severobaikalsky (Yarki and Millionny islands, Dagarskaya inlet tract) and Pribaikalsky (Karga inlet tract) districts. The association Astragalo sericeocani–Festucetum baicalensis was observed only at the northern coast of the lake, with the local habitat of the endemic species Astragalus sericeocanus. The sandy area near Turka village is characterized by a unique species composition. It is represented by the ass. Phlojodicarpo sibirici–Oxytropidetum lanatae. The Olkhon Isl. sandy vegetation includes both steppe species (Alyssum obovatum, Carex korshinskyi, Silene jeniseensis and Thymus baicalensis), and local endemics (Astragalus olchonensis and Agropyron angarense). The ass. Astragalo olchonensis–Chamaerhodetum grandiflorae and community Thymus pavlovii occur there.

The studied syntaxa are a part of the range of the class Brometea korotkyi with two orders, 4 alliances and 20 associations described within this class on the territory of Baikal Siberia so far. However, the position of 3 associations within alliances and orders is not defined (Hilbig, Koroljuk, 2000; Dulepova, Koroljuk, 2013, 2015).

In Baikal Siberia the above class is represented by the order Oxytropidetalia lanatae, including three alliances, 19 associations, 10 subassociations and 6 rankless communities. The analysis of floristic differentiation of the psammophytic vegetation syntaxa has shown the existence of a common group of species including diagnostic species of the order and class. The alliance Aconogonion chlorochryseiDulepova et Korolyuk 2013 combines communities on sands in the Verkhnecharskaya depression (Zabaikalsky district, Chita region) and is indicated by three species: Aconogonon chlorochryseum, Agropyron nathaliae and Silene amoena. The alliance comprises 4 associations, 3 subassociations and 2 communities. Species pool of the Chara sands includes 22 species, including diagnostic species of the alliance and order, and Dianthus versicolor, Carex argunensis, Pulsatilla turczaninovii and Silene jeniseensis (Dulepova, Koroljuk 2013).

The communities of the alliance Festucion dahuricaeDulepova et Korolyuk 2015 are developed in forest-steppe and steppe landscapes of the mountain-steppe zone in the Selenga river basin (Dulepova, Koroljuk 2015). Here sandy areas are in close contact with steppe ecosystems, which defines the main feature of the psammophytic vegetation species pool, namely high representation of widespread steppe species such as Carex korshinskyi, Cleistogenes squarrosa, Dontostemon integrifolius, Serratula centauroides, Thermopsis lanceolata, Thymus baicalensis and Vincetoxicum sibiricum. A lot of these plants are involved in the diagnostics of the class Cleistogenetea squarrosae Mirk. et al. 1985, order Stipetalia krylovii Kononov, Gogoleva et Mironova 1985 and alliance Stipion krylovii Kononov, Gogoleva et Mironova 1985. The diversity of the communities within the alliance from the Selenga river basin is determined by the presence of obligate (Festuca dahurica, Aconogonon sericeum) and facultative psammophytes (Artemisia xylorhiza, A. xanthochroa, Ulmus pumila). The only exception is Malkhan-Elysun sandy area (the largest in Transbaikalia, about 11 km²) surrounded by dry pine forests. This unique territory of old origin is characterized by two species with disjunctive distribution in Buryatia and Tyva — Thesium tuvense and Corispermum macrocarpum. Vegetation of the Malkhan-Elysun sands is also characterized by high frequencies of Linum sibiricum, Scorzonera radiata, Silene jeniseensis and Aconogonon sericeum. The alliance Festucion dahuricae with common 72 species is represented by 4 associations, 2 subassociations and 3 communities.

The vegetation of Lake Baikal sandy coasts is incorporated into the alliance Oxytropidion lanatae, which has the largest number of diagnostic species, including several endemics: Aconogonon ochreatum, Astragalus sericeocanus, Corispermum ulopterum, Craniospermum subvillosum, Festuca rubra subsp. baicalensis, Leymus secalinus, Phlojodicarpus sibiricus and Scrophularia incisa. Its species pool is richer than in the Chara and Selenga areas and counts 85 species. Sand areas are in a close contact with forests, meadows and wetlands, whereby psammophyte flora is enriched by species of the nearby environments, such as Artemisia monostachya, Carex acuta, Festuca ovina subsp. vylzaniae, Vaccinium vitis-idaea and V. uliginosum.

Key words: vegetation, sandy massifs, beaches, Brometea korotkyi, Lake Baikal, the Republic of Buryatia, Irkutsk region

Section: Articles

How to cite

Dulepova N. A. 2016. Vegetation of sandy coasts of Lake Baikal // Vegetation of Russia. N 29. P. 46–66. https://doi.org/10.31111/vegrus/2016.29.46

Received May 6 2016

References