For this World Rewilding Day, we explore the vast, open landscapes of the Kazakh Steppe with Dr. Alyona Koshkina and Dr. Ilya Smelansky, two leading scientists based at ACBK. Together, they share insights into the complex interactions between steppe fauna – from top predators to burrowing mammals – and how these relationships shape the wider ecosystem.

In this Q&A, Alyona and Ilya discuss the cultural and ecological significance of restoring emblematic species, such as wolves and eagles, as well as the often-overlooked roles played by animals across all trophic levels. They also reflect on the Pleistocene steppe, once home to megafauna like woolly rhinos and mammoths alongside lions and cheetahs, and consider what restoring some of these functions could mean for today’s landscapes.

Q: When we talk about restoring species to the Kazakh Steppe, we often focus on ecological function-but there’s also deep cultural meaning. How do these two values come together, for example in the return of Przewalski’s horse to Kazakhstan?

Alyona: Horses are deeply related to nomadic culture and heritage in Kazakhstan, and this is reflected in, for example, our national games as well as the sense of pride Kazakhs have for their historic nomadic traditions, which symbolise freedom of movement. Horses are an essential component of nomadic life, and horses were first domesticated in Central Asia thousands of years ago. The reintroduction of Przewalski’s horse therefore carries emotional and symbolic meaning.

Also, species including the wolf and eagles, which are central to rewilding efforts, are very charismatic and important totems of different Kazakh tribes. For example, the golden eagle can often be found in cultural artefacts and traditions. Therefore, trophic rewilding has strong potential to foster important symbolic meaning in Kazakhstan.  

Q: Is there a species-or group of species-without which the steppe simply couldn’t function? What makes them so fundamental to the system?

Ilya: Essential components are the “graminoids” – that is, different species of grasses, especially tussock grasses. Concerning animals, crucial players in the ecosystem include herbivorous ungulates, burrowing rodents and pikas, as well as locusts.

Q: In a healthy steppe ecosystem, nothing is wasted. Could you walk us through how nutrients move through the system-from grazing to dung, carcasses, and decomposition-and why this cycle is so critical?

Alyona: In healthy steppe ecosystems, movement of nutrients is shaped mainly by two competing processes – grazing and fire. These processes essentially compete for the same aboveground biomass. But really, the nutrient cycle begins deep belowground, because most of the energy in the steppe is stored in the form of humus in soils and the root biomass of plants, alongside soil invertebrate fauna and burrowing mammals, which are also a big part of these underground processes.

In fact, steppes are described in ecology as “upside-down forests”, because of this biomass and nutrients that are stored underground rather than aboveground. This reflects an adaptation to the harsh climate – cold winters and dry periods.

Belowground, nutrients are “born”, and then turn into aboveground biomass, entering different pathways. The first pathway goes to grazers, transforming plants into dung and urine. This returns nutrients to the soil again, stimulating microbial activity and increasing soil fertility, which in turn benefits plants through nutrient provision.

The carcasses of grazing animals provide resources for scavengers such as vultures, mesopredators, and insects. This decomposition process redistributes energy across these various trophic levels.

However, grazers are not the only actors. Steppes are also very pyrogenic systems, with fire acting as a natural competitor to grazing and historically a very frequent process. Fires will eventually consume vegetation if there are not enough grazers. Nutrients are then released – some lost to the atmosphere, and some returned to the soil – while fire can also boost carbon sequestration in the post-fire period.

The balance between these different pathways – grazing and fire – ultimately shapes the movement of nutrients: how they accumulate and how they cycle.

Q: How do large herbivores like the saiga antelope shape vegetation and soils at scale, and what changes when they recover or disappear?

Alyona: Large herbivores like saiga impact soil and vegetation – not just by consuming vegetation, but through trampling and selective grazing – which organises the steppe into a mosaic of habitats.

In a healthy steppe ecosystem, large herbivores with different grazing niches interact with soils and vegetation in different ways. Herbivory is not dominated by a single species; instead, there are selective feeders on herbaceous plants, like saiga, as well as small mammals that also consume a significant amount of biomass. There are also large grazers, such as horses, which consume and trample grasses. Historically, these included bison and aurochs, which strongly influenced vegetation.

These groups would coexist and complement each other, usually without overlapping, as they occupy different niches.

As saiga were once more mobile and selective, they help maintain plant diversity through selective grazing and by promoting the regrowth of herbaceous plants. However, they have a relatively light impact on physical structure, as they are not as effective at trampling.

Conversely, large grazers like horses consume large amounts of grasses and physically modify vegetation composition. They create patches of shorter, more open vegetation, which makes the habitat more accessible and suitable for saiga, who prefer less grassy areas with more herbaceous plants.

Together, saiga and horses create conditions for smaller herbivores, such as burrowing mammals, which depend on shorter grasses. It becomes a cascade: small mammals, in turn, impact the soil through burrowing activities and by accelerating the nutrient cycle described earlier.

Q: Some of the most important processes in the steppe are hidden. What are the ‘invisible’ parts of this ecosystem that people often overlook?

Ilya: A defining feature of steppe ecosystems is the distribution of biomass above and below ground: around 70-90% is located underground and usually remains invisible to us. Most of the steppe’s invertebrates, reptiles, and many mammals inhabit the soil, often only emerging to the surface in exceptional cases.

These organisms – together with fungi and plant roots – drive the majority of ecosystem processes. They support plant growth, unlock nutrients from dung and dead biomass, and transform these into fertile humus. In addition, they restructure the soil, loosening it and increasing its porosity.

Q: Which species have been lost from Kazakhstan’s steppe ecosystems, and what roles did they play? (e.g. Wooly Rhino, Mammoths, etc.)

Alyona: The steppes of Kazakhstan are, in many ways, an ecological legacy. What we have today is just a fragment of a formerly richer fauna.

In the past, these landscapes supported a diverse guild of large herbivores and several top predators. Species such as woolly mammoths, woolly rhinoceros, aurochs (the wild cow), together with wild horses, and large predators such as lions and hyenas, were all present. Today, however, we are often left with only wolves.

Altogether, these animals formed diverse, functional systems. Many of these species likely declined or disappeared due to climate change at the end of the Pleistocene era. In other regions of the world, defaunation is debated in terms of whether it was driven primarily by climate change or Homo sapiens expansion. In this part of the world – the temperate steppes of Eurasia – it was mostly climate change.

There have also been more recent losses due to human expansion, such as the extinction or decline of large horses, kulan, the Asiatic cheetah, and significant declines in scavenger communities. These represent substantial ecological losses.

The Pleistocene guild of herbivores and top predators played complementary roles, with species occupying different feeding niches. Today, we often have only one representative for each niche. For example, in many areas, saiga are the only remaining large herbivore, while in others there may also be argali – but typically just one or two species.

Similarly, there is now often only one top predator – the wolf. With the loss of these species, we have lost key ecological functions, including bulk grazing of grasses and diverse forms of selective feeding on herbaceous plants.

In the past, these species collectively shaped the landscape. Without them, we do not fully know how these ecosystems would function – or what the steppes of Kazakhstan would look like today if they were still present.

Q: Do we see gaps in ecological function today because of those losses-and are any species acting as replacements or proxies?

Alyona: Gaps in ecological function are now partially filled by a transformed socio-ecological system that emerged after the loss of the purely wild one.

Many of the original functions of large, migratory herbivores are now carried out by domestic animals. Specifically, horses and cattle share the closest functional similarities with extinct herbivores such as wild horses, bison, and aurochs. In contrast, sheep grazing is usually less similar to the roles and grazing patterns of wild herbivores.

This shift is a result of the integration of mobile pastoralism into steppe systems. Over time, it became part of the system, forming a socio-ecological system characterised by the seasonal movement of livestock across landscapes.

To some degree, this has substituted for the functions of large herbivores. However, there is a key difference: the movement of domestic animals is controlled, and in many places has become more sedentary, particularly following political and land-use transformations over the last century.

Q: The saiga antelope has been part of this landscape since prehistoric times. How does that deep history shape your vision for a restored steppe?

Ilya: Virtually all wild species inhabiting the steppe today have been part of this landscape since prehistoric times. For more than 10, 000 years, they shaped the steppe ecosystem, until humans began to destroy it by using the fertile steppe soils for crops. Prehistoric megafauna once roamed these lands as well, but the state of the ecosystem that we want to save is not its prehistoric state. Instead, we strive to restore the conditions that were relatively sustainable before people started turning pristine steppe into arable lands at scale and permanent settlements replaced the ancient practice of mobile pastoralism. This transformation began approximately 200-300 years ago and it marks our reference for restoration.

Q: What are the tangible benefits to people (ecological, cultural, or economic) of restoring wild species and their interactions?

Ilya: Restoring wild species makes their ecosystems more sustainable and better functioning. Regulated and stable ecosystems, in turn, have greater capacity to provide ecosystem services, such as clean air and drinkable water, which people can use. Healthy ecosystems are also more resilient to climatic and other stresses, and tend to follow fairly predictable dynamics.

Some of the species being restored in Kazakhstan are culturally significant – for example, wolves, tigers, wild horses, and saiga – and some even carry sacred value. Beyond these cultural benefits, successful restoration can also deliver economic value. This is evident with species such as the saiga, steppe marmot, and European beaver: once on the brink of extinction, they have recently become abundant enough to return high economic value, both as objects of regulated hunting and as ecosystem engineers influencing landscapes over vast areas.

Q: How do wild herbivores and livestock interact on the steppe-are they competing, complementary, or more complex?

Ilya: The grazing patterns of some wild herbivores – such as wild horses, kulans, goitered gazelles, and wild sheep – can potentially compete with cattle and domestic horses, and to a lesser extent with domestic sheep.

The most abundant wild herbivore in Kazakhstan, the saiga antelope, prefers plants that are less favoured by cattle and horses. This does not mean that saiga avoid livestock resources entirely, but the vegetational heterogeneity of the steppe is usually sufficient to allow coexistence, with saiga and cattle using different vegetation patches.

Potential competition can become significant, however, in areas with limited resources. This usually occurs in regions that are overgrazed by livestock, often due to suboptimal pasture management.

Another shared and scarce resource in steppe landscapes is water. During the hot summer months, wild ungulates can compete with livestock for watering points. In these situations, wild herbivores often make use of artificial watering points built for livestock, allowing them to access habitats that would otherwise be unsuitable.

Feeding competition between livestock and smaller herbivores, such as rodents and insects, is also possible, but it tends to arise only occasionally in areas heavily overgrazed by domestic ungulates.

Q: What role do predators play beyond simply controlling prey numbers?

Alyona: Observations show that predators do not strongly impact prey numbers directly; rather, their function is one of indirect control – shaping the behaviour and space use of animals.

Some studies from the Soviet period suggest that even top predators exist at ratios with prey populations that make direct population control unlikely. Instead, they create a “landscape of fear”, where prey species, such as saiga, adjust their movements and behaviour in response to predator presence.

Top predators also help create different ecological niches for smaller mesopredators, which are often opportunistic scavengers and can fulfil multiple roles within the ecosystem.

In addition, predators contribute to nutrient cycling by creating carcasses, which provide resources for scavengers and decomposers, thereby supporting wider food webs.

Overall, their main role is not direct control of prey populations, but a range of indirect impacts on ecosystem structure and function.

Q: Scavengers are often overlooked, what role do they play?

Ilya: Scavengers are vitally important in the pastoral ecosystems of the steppe. In such ecosystems the large and medium herbivores are key elements of the food chains. The principal flows of energy, biomass, and nutrients run from plants through the herbivores to the soil-dwelling destructors – and then return back to the plants (and partly deposited in soils). 

The central medium of this circuit are the herbivores’ excrements – and also their carcasses. Carcasses of large herbivores are an important element of open landscapes like steppes and savannas. Under the influence of scavengers, their intrinsic nutrients and substances become more available to destructors in the soil – and then to plants again.

Q: Small mammals are often overlooked, what role do they play?

Alyona: Yes, small mammals are easy to overlook, but they play a fundamental role. This can be illustrated by the fact that they often represent over 70% of all mammal species in steppe ecosystems.

The role we are most aware of, and often talk about, is their position in trophic connections – serving as prey for a range of predators. However, another equally important role is their burrowing behaviour. By digging extensive tunnel systems, they bring deeper soil to the surface, turn the soil, and improve aeration and water regimes, as well as influencing seed germination.

This kind of landscape engineering is fundamental in such flat environments as the steppe. It creates a heterogeneous relief, which is often equivalent to habitat diversity.

But, as mentioned, they are closely linked to food webs, serving as primary prey for a wide range of predators and helping to transfer energy across trophic levels.

Q: When you’re out in the steppe, what moments make you feel that this is a truly wild system?

Ilya: I feel the sense of wilderness in moments when human presence is minimal – when there are no buildings, tree plantings, or agricultural fields in sight. Some wild animals are visible – sousliks or marmots on their mounds, raptors soaring overhead or patrolling the ground, lizards scuttling between my feet, and numerous invertebrates, particularly grasshoppers and locusts in mid-summer.

Most of these animals are not unique to untouched landscapes and can also be seen in agricultural areas. Only some species, such as saiga, argali, steppe eagles, or demoiselle cranes, are more reliable indicators of the landscape’s wild character. Of course, there are many other species absent from agricultural environments, but these tend not to be visible without special effort.

For anyone with botanical knowledge, there are also numerous plant-based indicators that distinguish a wild steppe from a transformed one.

Alyona: For me, the sense of wilderness is closely tied to openness – specifically, the absence of real barriers between human settlements and nature. This openness supports large-scale movements of wildlife, such as saiga, which are rare in many other parts of the world. While most open landscapes elsewhere are fenced, much of Kazakhstan remains largely unfenced.