Grassland biomes comprise various types of ecosystems characterized by open vegetation dominated by grasses and low shrubs, typically with low or no tree cover. Recent research has emphasized the importance of old-growth grasslands in both tropical and temperate regions (Parr et al. Reference Parr, Lehmann, Bond, Hoffmann and Andersen2014, Veldman et al. Reference Veldman, Buisson, Durigan, Fernandes, Le Stradic and Mahy2015, Bond Reference Bond2016, Reference Bond2019), significantly enhancing understanding of these ecosystems. These grasslands or mixed tree–grass systems may extend over large regions determined by climate conditions, where low rainfall or cold temperatures limit tree growth (Whittaker Reference Whittaker1970). In the tropical and subtropical zones, feedback mechanisms between disturbances such as fire and herbivory and grasses can also maintain grasslands as alternative states in regions with sufficient precipitation to support closed-canopy forests (Sankaran et al. Reference Sankaran, Hanan, Scholes, Ratnam, Augustine and Cade2005, Hirota et al. Reference Hirota, Holmgren, Van Nes and Scheffer2011, Staver et al. Reference Staver, Archibald and Levin2011, Bernardi et al. Reference Bernardi, Holmgren, Arim and Scheffer2016, Dantas et al. Reference Dantas, Hirota, Oliveira and Pausas2016, Bond Reference Bond2019). In temperate regions, similar feedbacks can also sustain open states, suggesting that alternative biome states (Pausas & Bond Reference Pausas and Bond2020) can coexist within the same environmental conditions (Ratajczak et al. Reference Ratajczak, Nippert, Briggs and Blair2014, Stritih et al. Reference Stritih, Seidl and Senf2023). These insights are crucial for understanding tree-cover patterns in understudied regions such as Türkiye’s Central Anatolian steppes.

Central Anatolia is renowned for its biodiversity-rich grasslands (Kurt et al. Reference Kurt, Tug and Ketenoglu2006), but human activities over millennia have caused the loss of much of its original habitats (Şekercioğlu et al. Reference Şekercioğlu, Anderson, Akçay, Bilgin, Can and Semiz2011, Ambarlı et al. Reference Ambarlı, Zeydanlı, Balkız, Aslan, Karaçetin and Sözen2016), leading to the region becoming part of the Irano-Anatolian biodiversity hotspot (Mittermeier et al. Reference Mittermeier, Gil, Hoffman, Pilgrim, Brooks and Mittermeier2005). Today, human land use continues to pose a significant threat to the ecosystems of Central Anatolia. The ongoing expansion of croplands has reduced the extent of steppe habitats by nearly 50% over the last century. The remaining grasslands are intensively used for grazing, which has led to overgrazing and degradation of the natural steppe vegetation, and they have more recently been targeted by afforestation initiatives (Şekercioğlu et al. Reference Şekercioğlu, Anderson, Akçay, Bilgin, Can and Semiz2011, Ambarlı et al. Reference Ambarlı, Zeydanlı, Balkız, Aslan, Karaçetin and Sözen2016, Ayan et al. Reference Ayan, Yücedağ and Simovski2021, Yıldız et al. Reference Yıldız, Eşen, Sargıncı, Çetin, Toprak and Dönmez2022). Many biodiversity-rich areas in Central Anatolia lack effective protection (Şekercioğlu et al. Reference Şekercioğlu, Anderson, Akçay, Bilgin, Can and Semiz2011, Ambarlı et al. Reference Ambarlı, Zeydanlı, Balkız, Aslan, Karaçetin and Sözen2016, Eken et al. Reference Eken, Isfendiyaroğlu, Yeniyurt, Erkol, Karataş and Ataol2016), making grassland habitats increasingly vulnerable to human-related threats. Additionally, the history of human modification in the region spanning thousands of years complicates understanding of the original distribution of forests and steppe vegetation (Asouti & Kabukcu Reference Asouti and Kabukcu2014), which in turn hinders their effective management. For instance, the misconception that these steppes and forest-steppes were originally forest areas degraded by human activity has led to the widespread afforestation efforts across Central Anatolia (Çalışkan & Boydak Reference Çalışkan and Boydak2017, Ayan et al. Reference Ayan, Yücedağ and Simovski2021, Olowu et al. Reference Olowu, Riley and Avcı2024).

Palaeoecological data indicate that much of Central Anatolia has retained its steppe and forest-steppe vegetation throughout the Holocene period (Turner et al. Reference Turner, Roberts, Eastwood, Jenkins and Rosen2010, Şenkul et al. Reference Şenkul, Memiş, Eastwood and Doğan2018), despite changes in climate, fire patterns and human activity since the last glacial maximum. Today, although several patches of black pine (Pinus nigra), juniper (Juniperus spp.) and oak (Quercus spp.) forest exist in the highlands of the Central Anatolian plateau (Ambarlı et al. Reference Ambarlı, Zeydanlı, Balkız, Aslan, Karaçetin and Sözen2016, Kahveci Reference Kahveci2022), the region is predominantly covered by grass- or subshrub-dominated steppe vegetation, or by forest-steppes with varying degrees of tree and shrub cover, ranging from isolated trees to open woodlands, alongside the croplands that occupy much of the area (Çetik Reference Çetik1985, Kürschner & Parolly Reference Kürschner, Parolly, Werger and MA2012). Unlike many tropical grassland systems that are dominated by C4 plants, C3 plants have been prevalent in the Central Anatolian region since the Miocene period (Edwards et al. Reference Edwards, Osborne, Strömberg, Smith and Bond2010). Annual precipitation, sometimes as little as 300 mm, combined with harsh temperature extremes, including freezing conditions and water stress in many parts of Central Anatolia, as well as poor and acidic soils restrict tree growth and can account for the prevalence of steppic grasslands (Kenar & Kikvidze Reference Kenar and Kikvidze2019, Kahveci Reference Kahveci2022, R Bernardi et al., unpublished data 2024). In the forest-steppes of Central Anatolia, the growth dynamics of trees, particularly junipers, depend heavily on precipitation (Kahveci et al. Reference Kahveci, Alan and Köse2018). In addition, the presence of forest-steppes in certain areas of Central Anatolia, where local conditions are conductive to tree growth, may also be influenced by past and ongoing disturbance regimes such as fire and livestock grazing (Tavşanoğlu Reference Tavşanoğlu2017). Nevertheless, Anatolian forest-steppe vegetation is often perceived in Türkiye as a degraded ecosystem due to human activity, a common misconception in many Eurasian countries where this vegetation type is found (Erdős et al. Reference Erdős, Ambarlı, Anenkhonov, Bátori, Cserhalmi and Kiss2019). This belief extends to much of the Central Anatolian steppe vegetation, which is frequently mischaracterized as secondary vegetation resulting from the loss of primary forests, despite palaeoecological evidence showing the dominance of steppe and forest-steppe vegetation throughout the region (Turner et al. Reference Turner, Roberts, Eastwood, Jenkins and Rosen2010, Şenkul et al. Reference Şenkul, Memiş, Eastwood and Doğan2018), which has transitioned over time with climatic fluctuations (Oybak-Dönmez et al. Reference Oybak-Dönmez, Ocakoğlu, Akbulut, Tunoğlu, Gümüş and Tuncer2021).

Another conventional approach to the Anatolian steppes is to label some areas as secondary steppes that have lost their primary steppe vegetation community due to centuries of grazing (Kurt et al. Reference Kurt, Tug and Ketenoglu2006, Kürschner & Parolly Reference Kürschner, Parolly, Werger and MA2012). This perspective overlooks the natural role of herbivory in shaping vegetation patterns and fails to consider that current grazing by domestic herbivores has replaced the herbivory of large-mammal communities during the Pleistocene. These so-called secondary steppes possess high biodiversity value and support numerous endemic and narrowly distributed plant taxa (Çetik Reference Çetik1985). In fact, in regions where the historical cover of woody plants is uncertain, the current biodiversity can serve as an indicator of old-growth vegetation. Many characteristics observed in these steppes and forest-steppes align with the markers of old-growth grasslands (Veldman et al. Reference Veldman, Buisson, Durigan, Fernandes, Le Stradic and Mahy2015, Bond Reference Bond2019). Specifically, old-growth Central Anatolian grasslands feature unique species assemblages not found in young secondary grasslands (such as old-fields), high species diversity in the herbaceous layer, abundant small-scale species richness, the presence of persistent bud banks, strong resprouting ability and widespread clonal growth, while low-intensity domestic livestock grazing helps preserve species diversity (Çetik Reference Çetik1985, Kurt et al. Reference Kurt, Tug and Ketenoglu2006, Fırıncıoğlu et al. Reference Fırıncıoğlu, Şahin, Seefeldt, Mert, Hakyemez and Vural2008, Kenar Reference Kenar2017, Özüdoğru et al. Reference Özüdoğru, Özüdoğru and Tavşanoğlu2021, Bahar & Tavşanoğlu Reference Bahar and Tavşanoğlu2024, Ülgen & Tavşanoğlu Reference Ülgen and Tavşanoğlu2024, Ç Tavşanoğlu, unpublished data 2021). For example, local-scale plant diversity is notably high in many Central Anatolian grasslands, with 116 species recorded in just 32 plots of 1 × 1 m in size (Özüdoğru et al. Reference Özüdoğru, Özüdoğru and Tavşanoğlu2021), 41 species in eight plots of 8 × 8 m in size (Kenar & Ketenoğlu Reference Kenar and Ketenoglu2016) and 78 species in 37 point transects of 50 m in size (Fırıncıoğlu et al. Reference Fırıncıoğlu, Şahin, Seefeldt, Mert, Hakyemez and Vural2008), exceeding or comparable to many species-rich grasslands in the Palearctic (Sankaran Reference Sankaran2009, Biurrun et al. Reference Biurrun, Pielech, Dembicz, Gillet, Kozub and Marcenò2021). At least a third (514 taxa) of polycarpic hemicryptophytes in Anatolian steppes possess belowground organs with clonality or perennation functions (Ülgen & Tavşanoğlu Reference Ülgen and Tavşanoğlu2024), and resprouting perennial species constitute 35% of the vegetation in a specific Central Anatolian habitat (Özüdoğru et al. Reference Özüdoğru, Özüdoğru and Tavşanoğlu2021). As a defining characteristic of natural grasslands, the widespread occurrence of clonal growth and resprouting ability enhances the resilience of Central Anatolian vegetation to various disturbances and harsh climatic conditions. Modelling suggests that moderate grazing supports the diversity and abundance of different plant functional groups in Central Anatolian steppes (Bahar & Tavşanoğlu Reference Bahar and Tavşanoğlu2024). These indicators of the old-growth nature of treeless steppe vegetation in Central Anatolia can also be applied to the forest-steppes in the region, which exhibit a high proportion of herbaceous species relative to tree species (Çetik Reference Çetik1985, Kenar Reference Kenar2017, Balpinar et al. Reference Balpinar, Kavgaci, Bingöl and Ketenoğlu2018, Ç Tavşanoğlu and R Bernardi, personal observations 2022) and host unique plant assemblages that are clearly distinct from other steppe vegetation types (Kenar & Ketenoğlu Reference Kenar and Ketenoglu2016, Balpinar et al. Reference Balpinar, Kavgaci, Bingöl and Ketenoğlu2018). These observations on the forest-steppes of Central Anatolia align with findings from other Eurasian grasslands that have steppe and forest-steppe characteristics (Dulamsuren et al. Reference Dulamsuren, Hauck and Mühlenberg2005, Erdős et al. Reference Erdős, Tölgyesi, Körmöczi and Bátori2015, Tölgyesi et al. Reference Tölgyesi, Valkó, Deák, Kelemen, Bragina and Gallé2018).

In conclusion, we argue that the grasslands of Central Anatolia, including both steppes and forest-steppes, are old-growth systems that deserve conservation. They should not be viewed as degraded vegetation but as diverse ecosystems that may have coexisted as alternative biome states with forests at different times in history. Therefore, it is crucial to prioritize and value these grassland ecosystems to improve their management, preservation and resilience to climate change. This effort should include re-evaluating current afforestation initiatives, as the region’s limiting climate conditions for tree growth could be exacerbated by climate change. The rich and highly diverse grasslands of the region may be more resilient than woodlands created by afforestation, which could face die-off or widespread fires in the future. A comprehensive conservation approach should address the loss of old-growth grasslands in Central Anatolia and explore opportunities to restore and rewild both steppes and, where local conditions are favourable, steppe-forests, informed by a deeper understanding of the historical distribution and current dynamics of these vegetation types.