Land use change in post-soviet Russia has led to the abandonment of between 50 and 80 million hectares of former agricultural land. Most of this has remained uncultivated and has reverted to either forests or steppe. A class of largely treeless grassland, the steppe biome plays important roles in biogeochemical cycling, carbon sequestration, and harbouring biodiversity. Though detailed information on the geographic layout of the reverted land is lacking, the change may contribute to reducing the fragmentation of the landscape, thereby increasing its potential species richness.
In a new article published in Landscape Ecology, lead author Robert Pazur and colleagues analyzed the changing spatial patterns of the steppe landscape on southern Russia over the past 40 years. Using the central Orenburg province as a proxy for the region, the authors studied satellite imagery and mapped both permanent steppe and steppe restoration from 1990 to 2018, considering various physical and economic factors in changing land usage.
In 2018, 70% of the steppe landscape in Orenburg province represented permanent steppe, while 30% was made up abandoned cropland. In total, around 57% of the province (up from 40% in 1990) was made up of managed and unmanaged steppe grasslands. Permanent steppe and land abandoned in the immediate post-socialist era (1990-2000) tended to be located on marginal land, far from settlements and on rough terrain. Much of this came from areas that had been a part of the Virgin Lands Campaign of 1954 to 1963, in which 20 million hectares of fallow and virgin Russian steppe, much of it marginal, were ploughed up in the name of agricultural development. Later patterns of abandonment and steppe restoration (2000-2018) tended to be more influenced by poor agro-climatic conditions or distance from adequate crop storage facilities.
Restored steppe has decreased the overall fragmentation of the natural landscape, providing corridors for wildlife. Those areas that are still patchy and unconnected today tend to exist in close proximity to today’s areas of intensive agriculture. “[This] implies that in intensively used areas, the steppe was restored only to a mosaic of isolated patches which do not allow for the essential migration and re-population of flora and fauna species, thus bearing the risk of local extinction of isolated populations,” write the authors. These patches would benefit from attention via restoration programmes, they note.