Trophic rewilding and pasture management as determinants of ecosystem functioning and biodiversity on the Kazakh steppe (TroPasKa)

Large herbivores shape grassland ecosystems through grazing, trampling and nutrient cycling. In many grasslands, their effects are closely linked with fire regimes. The grazing-fire interaction can influence vegetation structure, plant and animal diversity and ecosystem functioning. However, most of what we know about these interactions comes from African savannas and North American prairies. Research outcomes also depend strongly on herbivore identity and local conditions. This makes it difficult to generalize findings and limits our ability to predict fire–herbivory interactions in other ecosystems. Experimental research is therefore needed to isolate the mechanisms involved, particularly where evidence is scarce or mostly observational.

The Eurasian steppe is one of the largest continuous grasslands on Earth, extending from Eastern Europe to northern China, and a large part of it lies in Kazakhstan. Large herbivores such as Saiga (Saiga tatarica), the Kulan or Asiatic wild ass (Equus hemionus) and Przewalski’s horse (Equus ferus przewalskii) are characteristic native herbivores. Over the past decades, wild herbivore and livestock populations have changed substantially. The wild species were once widespread across the Kazakh steppe, but their numbers declined or they disappeared due to hunting, poaching and agricultural expansion. After the break-up of the Soviet Union in 1991, Saiga poaching increased, livestock numbers fell sharply, and fires became more frequent as fuel accumulated on the “undergrazed” rangelands. In recent years, this has again changed dynamically. Saiga have recovered to more than 4.6 million individuals, Kulan and Przewalski’s horses are being reintroduced through rewilding programmes, and livestock numbers are increasing rapidly again. These changes in grazing systems have occurred alongside shifts in fire regimes and a changing climate, including earlier snowmelt and longer growing seasons. It is therefore important to test how returning wild herbivores interact with fire and a changing climate to affect the steppe, in time and space.

In project TroPasKa, we will implement three research subprojects:

We will set up grazing exclosures in protected areas and in nearby villages, with experimental burning and snow removal treatments nested in the exclosures. We ask how grazing by wild an domestic ungulates affects steppe vegetation structure and composition, and how this interacts with earlier snowmelt. We will also investigate, how dung beetle communities vary with grazing animals. This part is led by Lakshmi Niranjana and Albert Salemgareev.
Using a very large database of GPS-tracked domestic horses (kept for milk and meet, with large home ranges), we will study the interaction of steppe fires and horse grazing. We postulate an attraction of horses to fresh regrowth on recently burnt steppe, and a decreased burn risk where large flocks of horses graze (led by Eliah Grooß and Magzhan Ikram).
We will quantify changes in grazing systems by structured interviewswith private livestock companies and pastoralists (led by Narkyz Makhmet, Alyona Koshkina and Johannes Kamp). We will resurvey a large number of plots with bird counts that were surveyed in 2009/2010 to detect effects of recovering wild ungulate and livestock populations on biodiversity (led by Albert Salemgareev).

In this project (runtime 2026–2031), we collaborate with the Association for the Conservation of Biodiversity of Kazakhstan (ACBK), iGPS in Astana and researchers from Harvard University (Jonas Trepel), the University of Alberta (Erick Lundgren) and the University of Münster (Norbert Hölzel). The project is largely funded by internal funds of the Universities of Göttingen and Münster.

Photo credits:
Top left: Fencing work for the large exclosures (Photo: A. Salemgareev)
Top right: Kulan (Equus hemionus), translocated to Central Kazakhstan (Photo: J. Kamp)
Box 1: Exclosure design (Drawing: L. Niranjana)
Box 2: Domestic horses (Photo: J. Kamp)
Box 3: Interview with shepherd (Photo: J. Kamp)