Subalpine tall-herb vegetation in Bulgaria: diversity and ecology

Abstract

Class Mulgedio-Aconitetea comprises plant communities that develop primarily in the upper montane to subalpine vegetation belts. It is vegetation where tall herb species (forbs, ferns, grasses) occur dominantly; in the Balkans, it was studied only marginally. In this article, based on floristic composition we assess two questions: (1) what is the diversity of the class Mulgedio-Aconitetea in Bulgaria and (2) what environmental factors are responsible for the vegetation assemblages in the area? We analyzed 387 plots. We created an expert system that classifies this vegetation and tested environmental variables for their influence on these vegetation types. In total, 15 associations and one uncategorized community were classified using the Braun-Blanquet approach. The length of the growing season (number of growing degree days > 0 °C) and climate moisture have a significant effect on the vegetation. Disturbance severity, disturbance frequency and reaction have influence over the species scores. Moreover, all variables significantly differed between the vegetation types.

Keywords:

• Alpine
• Balkans
• distribution
• phytosociology
• vegetation diversity

Acknowledgements

We would like to thank Jakub Tešitel for suggestions regarding the analysis of data, Milan Chytrý and Zdeňka Lososová for revising the text, Irena Axmanová and Salza Palpurina for useful comments and help with species nomenclature, Michal Hájek and Petra Hájková for useful comments on early version of the manuscript.

Authors’ contributions

DS conceived the idea, analysed the data and interpreted them, wrote the expert system, text and created maps. All authors sampled the vegetation. All authors revised the text and approved of its final form.

Disclosure statement

No potential conflict of interest was declared by the authors.

Notes

1 Nomenclature type: Roussakova 2000, p. 116, tab. 42, relevé no. 1 (typus).

2 Synonym: Carici bulgaricae-Deschampsietum cespitosae Roussakova 2000; Carex lazarei Jac.Koopman, Niketic, Wieclaw & Govaerts [nom. illeg. Carex bulgarica (Domin) Lazare].

3 In the Balkans, this alliance is reported from Kosovo (Rexhepi 1994), North Macedonia (Horvat 1960), and Bulgaria (Szokala 2023). There is historically only one association in the Balkans named Knautio-Calamagrostietum arundinaceae. It occurs in several literature sources (Horvat 1960, Horvat et al. 1974, Rexhepi 1994); however, they most likely refer to the hand-written manuscript of Horvat from 1949 (see Lakušić et al. 2015), and thus it is not an effectively published name (Theurillat et al. 2021 Art. 1).

4 Typus Saxifrago rotundifoliae-Athyrietum distentifolii. Author: M. Kočí. Date: 12.07.2003. GPS 23°29’38″ N, 42°07’14″ E. Locality: Rila, Ribni jezera ca 0.5 km NNE of the Ribni jezera cottage. Habitat: Heel of a rock, near a scree cone. Relevé area: 10 m². Altitude: 2172 m a. s. l. Slope: 20°. Cover: E_total 60%, E₁ 60%, E₀ 5%. Species – E₁: Athyrium distentifolium 3, Doronicum austriacum 2a, Festuca rubra L. 2a, Rumex arifolius 2a, Dryopteris filix-mas 1, Gentiana punctata L. 1, Geranium sylvaticum 1, Geum montanum L. 1, Jasione bulgarica Stoj. & Stef. 1, Milium effusum L. 1, Saxifraga rotundifolia 1, Vaccinium myrtillus 1, Veratrum lobelianum 1, Anthoxanthum odoratum agg. +, Avenella flexuosa +, Cirsium appendiculatum +, Doronicum columnae +, Homogyne alpina (L.) Cass. +, Ligusticum mutellina +, Poa ursina +, Potentilla crantzii (Crantz) Beck ex Fritsch +, Ranunculus montanus Willd. +, Sedum alpestre Vill. +, Senecio nemorensis L. +, Vaccinium uliginosum L. +, Crocus veluchensis Herb. R, Gymnocarpium dryopteris (L.) Newman r. E₀: not analysed.

5 Typus Moehringio pendulae-Cicerbitetum alpinae. Author: M. Kočí. Date: 13.07.2003. GPS 23°24’05″ N, 42°29’27″ E. Locality: Rila river, valley near Rila monastir, ca 2 km E of Kirilova poljana. Habitat: Slight depression in opening of spruce-fir dominated forest. Relevé area: 16 m². Altitude: 1768 m a. s. l. Slope: 10°. Cover: E_total 100%, E₁ 100%, E₀ 40%. Species – E₁: Cicerbita alpina 4, Dryopteris filix-mas 2b, Calamagrostis arundinacea 2a, Geranium sylvaticum 2a, Prenanthes purpurea L. 2a, Senecio nemorensis 2a, Solidago virgaurea +, Campanula trichocalycina Ten. 1, Geum coccineum 1, Epilobium angustifolium 1, Hypericum maculatum 1, Lilium martagon 1, Luzula sylvatica 1, Ranunculus platanifolius 1, Rumex arifolius 1, Vaccinium myrtillus 1, Veratrum lobelianum 1, Veronica urticifolia 1, Cruciata laevipes Opiz +, Melampyrum sylvaticum L. +, Moehringia pendula +, Melica nutans L. +, Myosotis sylvatica Ehrh. ex Hoffm. +, Silene vulgaris +, Sorbus aucuparia +, Oxalis acetosella +, Viola biflora +. E₀: not analysed.

6 Typus Aquilegio aureae-Doronicetum columnae. Author: M. Kočí. Date: 08.07.2003. GPS 23°38’25″ N, 42°10’01″ E. Locality: Kazana glacial cirque, base of rock outcrops, middle part of eastern slope. Habitat: base of rock otcrops. Relevé area: 15 m². Altitude: 2350 m a. s. l. Slope: 40°. Cover: E_total 90%, E₁ 90%, E₀ 0.5%. Species – E₁: Geranium sylvaticum 3, Aquilegia aurea 2b, Saxifraga rotundifolia 2b, Festuca rubra 2a, Geum coccineum 2a, Senecio nemorensis 2a, Soldanella pindicola Hausskn. 2a, Veratrum lobelianum 2a, Aconitum lycoctonum L. 1, Angelica sylvestris 1, Cirsium appendiculatum 1, Doronicum columnae 1, Festuca valida 1, Hypericum maculatum 1, Knautia arvensis agg. 1, Luzula alpinopilosa (Chaix) Breistr. 1, Rhodiola rosea L. 1, Rumex arifolius 1, Koenigia alpina +, Alchemilla glabra Neygenf. +, Alchemilla vulgaris agg. +, Arabis alpina L. +, Carex sempervirens Vill. +, Centaurea nervosa +, Crepis conyzifolia (Gouan) A.Kern. +, Epilobium angustifolium +, Galium anisophyllon Vill. +, Homogyne alpina +, Ligusticum mutellina +, Myosotis alpestris F.W.Schmidt +, Phleum alpinum +, Poa nemoralis +, Polystichum lonchitis +, Ranunculus montanus +, Saxifraga paniculata +, Sedum alpestre +, Sesleria coerulans agg. +, Vaccinium myrtillus +, Viola tricolor L.+. E₀: Pleuropteropyrum undulatum (Murr.) A.Löve & D.Löve +.

Additional information

Funding

Research of DS was financed by Masaryk University’s REEE project MUNI/A/1489/2023.