Calciphilous communities with Thymus dubjanskyi Klokov et Des.-Shost. in the Samara region

Rare plant communities with the participation of Thymus dubjansky, an endemic of the Middle Volga region, were studied on the chalk slopes in the Samara region. Using the approach of J. Braun-Blanquet, a total of 30 relevés were processed with the JUICE software. The primary classification by the TWINSPAN algorithm revealed two distinctive communities. The DCA ordination was performed, and reliable correlations were found between the position of the phytocenoses and L.G. Ramensky’s environmental indicators. The identified communities differed in terms of their environmental indicators and exhibited floristic heterogeneity. They were represented by typical steppe taxa and calciphilous species, 30 % of which were rare. For the first time, two new associations were established in the сalciphilous vegetation of the Samara Pre-Volga region: Artemisio salsoloidis-Thymetum dubjanskyi ass. nov. hoc loco and Gypsophilо volgensis-Thymetum dubjanskyi ass. nov. hoc loco. Due to their narrow distribution range, the communities with Thymus dubjansky were classified only provisionally. The сalciphilous subshrub communities of the established associations correspond to the initial stages of overgrowth on the slopes and elevations of chalk massifs in the Samara region. Given the vulnerability of their substrate to natural and anthropogenic degradation, the phytocenoses with Thymus dubjansky should be considered rare.

1. Plaksina T.I. Analiz flory [Flora Analysis]. Samara, Izd. Samar. Univ., 2004. 152 p. (In Russian)

2. Vasjukov V.M., Saksonov S.V. Review of thymes (Thymus L., Lamiaceae) in the Samara region. Izv. Samar. Nauchn. Tsentra Ross. Akad. Nauk, 2012, vol. 14, no. 1, pp. 64–68. (In Russian)

3. Kalashnikova O.V., Plaksina T.I. Calciphilous flora on the chalk slopes of the Volga Upland in the Samara region. Izv. Samar. Nauchn. Tsentra Ross. Akad. Nauk, 2010, vol. 12, no. 1(3), pp. 691–695. (In Russian)

4. Ivanov A.M. Geologicheskoe stroenie Kuibyshevskoi oblasti [Geological Structure of the Kuybyshev Region]. Kuybyshev, Kn. Izd., 1960. 81 p. (In Russian)

5. Averinova E.A. Plant communities with Hedysarum grandiflorum Pall. in the Central Russian Upland. Byull. Bryansk. Otd. RBO, 2014, no. 1(3), pp. 37–47. (In Russian)

6. Korolyuk A.Yu., Senator S.A., Vasjukov V.M., Zibzeev E.G. Sytaxonomy of some plant communities on the chalk slopes in the Lesser Bend of the Don River (Volgograd region). Bot. Zh., 2021, vol. 106, no. 2, pp. 166–176. https://doi.org/10.31857/S000681362102006X. (In Russian)

7. Golovanov Ya.M., Yamalov S.M., Lebedeva M.V., Korolyuk A.Yu., Abramova L.M., Dulepova N.A. Vegetation on the chalk slopes of the Sub-Ural Plateau and adjacent territories. Rastit. Ross., 2021, vol. 40, pp. 3–42. https://doi.org/10.31111/vegrus/2021.40.3. (In Russian)

8. Novikova L.A., Saksonov S.V., Vasjukov V.M., Gorlov S.E., Senator S.A., Solov’eva V.V. Vegetation of the Guryev Ravine Natural Monument (Shigonsky district, Samara region). Samar. Nauchn. Vestn., 2018, vol. 7, no. 2(23), pp. 90–94. https://doi.org/10.17816/snv201872118. (In Russian)

9. Novikova L.A., Saksonov S.V., Vasjukov V.M., Gorlov S.E., Senator S.A., Solov’eva V.V. Vegetation of the Levashovskaya Forest Steppe Natural Monument (Samara region). Samar. Luka: Probl. Reg. Global’noi Ekol., 2019, vol. 28, no. 1, pp. 81–91. https://doi.org/10.24411/2073-1035-2019-10185. (In Russian)

10. Bondareva V.V. Database of vegetation of the Middle Volga region. Phytodiversity East. Eur., 2022, vol. 16, no. 3, pp. 5–9. https://doi.org/10.24412/2072-8816-2022-16-3-5-9. (In Russian)

11. Tichý L. JUICE, software for vegetation classification. J. Veg. Sci., 2002, vol. 13, no. 3, pp. 451–453. https://doi.org/10.1111/j.1654-1103.2002.tb02069.x.

12. Czerepanov S.K. Vascular Plants of Russia and Adjacent States (the Former USSR). Cambridge, Cambridge Univ. Press, 1995. 532 p.

13. URL: https://www.ipni.org/.

14. Chytrý М., Tichý L., Holt J., Botta-Dukát Z. Determination of diagnostic species with statistical fidelity measures. J. Veg. Sci., 2002, vol. 13, no. 1, pp. 79–90. https://doi.org/10.1111/j.1654-1103.2002.tb02025.x.

15. Tichy L., Chytry М. Statistical determination of diagnostic species for site groups of unequal size. J. Veg. Sci., 2006, vol. 17, no. 6, pp. 809–818. https://doi.org/10.1111/j.1654-1103.2006.tb02504.x.

16. Ramenskii L.G., Tsatsenkin I.A., Chizhikov O.N., Antipin N.A. Ekologicheskaya otsenka kormovykh ugodii po rastitel’nomu pokrovu [Ecological Assessment of Forage Lands by Vegetation Cover]. Moscow, Sel’khozgiz, 1956. 472 p. (In Russian)

17. Zverev A.A. Informatsionnye tekhnologii v issledovaniyakh rastitel’nogo pokrova: uchebnoe posobie [Information Technology in Vegetation Research: A Tutorial]. Tomsk, TML-Press, 2007. 304 p. (In Russian)

18. Zelený D., Tichý L. Linking JUICE and R: New developments in visualization of unconstrained ordination analysis. Proc. 18th Workshop of European Vegetation Survey “Thermophilous Vegetation” (24–28 March 2009). Roma, 2009. Abstr., p. 123.

19. Borovikov V.A. Statistica. Iskusstvo analiza dannykh na komp’yutere [Statistica. The Art of Computerized Data Analysis]. St. Petersburg, Piter, 2003, 688 p. (In Russian)

20. Theurillat J.-P., Willner W., Fernández-González F., Bültmann H., Čarni A., Gigante D., Mucina L., Weber H. International Code of Phytosociological Nomenclature. 4th ed. Appl. Veg. Sci., 2021, vol. 24, no. 1, art. e12491. https://doi.org//10.1111/avsc.12491.

21. McCune B., Mefford M.J. PC-ORD. Multivariate Analyses of Ecological Data. Version 5. 2006. Gleneden Beach, OR, USA, MjM Software.

22. Mucina L., Bültmann H., Dierßen K., Theurillat J.-P., Raus T., Čarni A., Šumberová K., Willner W., Dengler J., García A.G., Chytrý M., Hájek M., Di Pietro R., Iakushenko D., Pallas J., Daniëls F.J.A., Bergmeier E., Guerra A.S., Ermakov N., Valachovič M., Schaminée J.H.J., Lysenko T., Didukh Y.P., Pignatti S., Rodwell R.S., Capelo J., Weber H.E., Solomeshch A., Dimopoulos P., Aguiar S., Hennekens S.M., Tichý L. Vegetation of Europe: Hierarchical floristic classification system of plant, bryophyte, lichen, and algal communities. Appl. Veg. Sci., 2016, vol. 19, no. S1, pp. 3–264. https://doi.org/10.1111/avsc.12257.

23. Krasnaya kniga Rossiiskoi Federatsii. Rasteniya i griby [Red Book of the Russian Federation. Plants and Fungi]. Moscow, VNII “Ekologiya”, 2024. 944 p. (In Russian)

24. Krasnaya kniga Samarskoi oblasti [Red Book of the Samara Region]. Vol. 1: Rare species of plants and fungi. Senator S.A., Saksonov S.V. (Eds.). Samara, Izd. Samar. Gos. Obl. Akad. (Nayanovoi), 2017. 380 p. (In Russian)

25. Didukh Y., Chusova O., Demina O. Syntaxonomy of chalk outcrop vegetation of the order Thymo cretacei-Hyssopetalia cretacei. Hacquetia, 2018, vol. 17, no. 1, pp. 85–109. https://doi.org/10.1515/hacq-2017-0013.

26. Demina O.N., Korolyuk A.Yu., Rogal’ L.L. Calciphilous steppes of the Rostov region. Rastit. Ross., 2016, no. 29, pp. 21–45. https://doi.org/10.31111/vegrus/2016.29.21. (In Russian)