The effects of micro-habitats and grazing intensity on the vegetation of burial mounds in the Kazakh steppes

Abstract

Background: Burial mounds (kurgans) of Eurasian steppes are man-made habitat islands that have the potential to harbour rich plant diversity due to micro-habitats associated with their topography.

Aims: We assessed whether kurgan micro-habitats harboured different species pools and functional groups from those found on the surrounding steppes. In addition, we asked if these mounds were affected by different grazing intensities from those on the surrounding vegetation.

Methods: We surveyed kurgan micro-habitats (northern and southern slopes, surrounding ditch) and adjacent steppe plains in non-grazed, moderately grazed and heavily grazed sites in northern Kazakhstan. We analysed differences in species composition of four habitats under three grazing regimes using Generalised Linear Mixed Models, PCA ordination and indicator species analysis.

Results: Kurgan micro-habitats had diverse vegetation and supported the co-existence of plant species with different environmental needs. We identified 16 steppe specialists confined to kurgan micro-habitats. Steppe vegetation was well-adapted to extensive grazing, although heavy grazing supported ruderals and a decline in steppe specialists. There was a significant interaction between grazing intensity and habitat type: heavy grazing supported ruderals and suppressed steppe specialists especially on the slopes.

Conclusions: We highlighted that kurgans play an important role as maintaining high plant diversity locally in extensive steppe plains in Central-Asia by increasing environmental heterogeneity and supporting specialist species confined to these micro-habitats.

Keywords:

• degradation
• kurgan
• livestock
• microsite
• plant diversity
• slope

Acknowledgements

We are thankful for László Nagy and for the two anonymous Reviewers for their useful comments on the manuscript. We are grateful to Marina and Ilya Bobrenko for their support during the fieldwork.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental data

Supplemental data for this article can be accessed here.

Additional information

Funding

The authors were supported by OTKA PD 115627 (BD), OTKA PD 111807 (OV), NKFI FK 124404 (OV), NKFI KH 126476 (OV), OTKA PD 116200 (AK), NKFI K 124796 (ZB) and NKFI FK 124579 (RG) projects. BD and OV were supported by the Bolyai János Research Scholarship of the Hungarian Academy of Sciences. BD and OV were supported by the ÚNKP-17-4-III-DE-160 and ÚNKP-17-4-III-DE-151 New National Excellence Program of the Ministry of Human Capacities. AK was funded by the MTA’s Post-Doctoral Research Program. CT received support from the EU-funded Hungarian grant EFOP-3.6.1-16-2016-00014. OV’s work was supported by the National Youth Excellence Scholarship [Grant Number NTP-NTFÖ-16-0107].

Notes on contributors

Balázs Deák

Balázs Deák studies the effects of landscape factors and habitat conditions on the species composition of isolated grassland fragments.

Csaba Tölgyesi

Csaba Tölgyesi, Zoltán Bátori and Róbert Gallé investigate plant and invertebrate diversity patterns of Eurasian forest steppes.

András Kelemen

András Kelemen studies the role of plant–plant interactions in shaping grassland vegetation dynamics.

Tatyana M. Bragina

Tatyana M. Bragina and Yerkin I. Abil are experts of the conservation and cultural heritage attributed to Central-Asian steppes.

Orsolya Valkó

Orsolya Valkó investigates the effect of grassland management on species composition and diversity.