Legacies of past land use challenge grassland recovery – An example from dry grasslands on ancient burial mounds

Abstract

Due to large-scale agricultural intensification, grasslands are often restricted to habitat islands in human-transformed landscapes. There are approximately half a million ancient burial mounds built by nomadic steppic tribes in the Eurasian steppe and forest steppe zones, which act as habitat islands for dry grassland vegetation. Land use intensification, such as arable farming and afforestation by non-native woody species are amongst the major threats for Eurasian dry grasslands, including grasslands on mounds. After the launch of the Good Agricultural and Environmental Condition framework of the European Union, in Hungary there is a tendency for ceasing crop production and cutting non-native woody plantations, in order to conserve these unique landmarks and restore the historical grassland vegetation on the mounds. In this study, restoration prospects of dry grassland habitats were studied on kurgans formerly covered by croplands and Robinia pseudoacacia plantations. Soil and vegetation characteristics were studied in thespontaneously recovering grasslands. The following questions were addressed: 1; How does site history affect the spontaneous grassland recovery? 2; Do residual soil nutrients play a role in grassland recovery? In former croplands, excess phosphorus, while in former Robinia plantations, excess nitrogen was present in the soil even four years after the land use change and grassland vegetation was in an early or mid-successional stage both on the mounds. The results showed that, without proper management measures, recovery of grassland vegetation is slow on mounds formerly used as cropland or black locust plantation. However, restoration efforts, focused on the restoration of mounds formerly covered by croplands, can be more effective compared to the restoration of mounds formerly covered by forest plantations.

Heritage of ancient cultures supports conservation: a continent-wide perspective from the Eurasian steppes

“…This suggests that in such landscapes, kurgans holding grasslands can function as habitat islands, and in this sense, their function is similar to that of other small natural features such as road verges, ravines, forest fringes, hedgerows, mid-field islets, old trees and inselbergs, which occur within and outside the steppe and forest steppe biomes (Hunter et al, 2017). As shown by former studies, the conservation potential of isolated kurgans is supported by their millennia-long existence and relatively undisturbed status, which enables them able to effectively preserve remnants of the original biota despite the marked level of land transformation in the neighbouring landscape (Deák et al, 2020, Dembicz et al 2020). However, it should be noted here that the number of kurgans reported in the EKDB might show a slight bias towards grassland-covered kurgans, as during data collection some surveyors might favor kurgans that are spectacular in some way, resulting in the overrepresentation of kurgans covered by grasslands.…”

“…In landscapes where grassland amount ranges between 1 to 40% kurgans holding grasslands can be essential integral parts of the landscape-level grassland network. By acting as stepping stones, these kurgans can enhance the functional spatial connectivity between the remaining grassland fragments and contribute to the maintenance of meta-population connections of grassland species (Deák et al, 2020).…”

“…Recent ecological studies revealed that millennia-old kurgans often hold dry grasslands and can act as habitat islands in transformed landscapes providing refuge for grassland species and maintaining high biodiversity (Apostolovaetal., 2022; Deák et al, 2020; Dembicz et al, 2020; Sudnik-Wójcikowska et al, 2011). All studies agree that the potential of kurgans for preserving grasslands is connected with their steep slopes, which impede ploughing (Deák et al, 2020; Dembicz et al, 2020).…”

“…Recent ecological studies revealed that millennia-old kurgans often hold dry grasslands and can act as habitat islands in transformed landscapes providing refuge for grassland species and maintaining high biodiversity (Apostolovaetal., 2022; Deák et al, 2020; Dembicz et al, 2020; Sudnik-Wójcikowska et al, 2011). All studies agree that the potential of kurgans for preserving grasslands is connected with their steep slopes, which impede ploughing (Deák et al, 2020; Dembicz et al, 2020). High environmental heterogeneity caused by the steep slopes of kurgans facing different cardinal directions also supports the co-existence of various microhabitats from mild to harsh even within a small area (Deák et al, 2021a; Lisetskii et al, 2016).…”

“…Although studies on animal biodiversity preserved by the kurgans are scarce, data from Hungary suggest that kurgans are also important sites for animal conservation. Among red-listed species, 21 ant, 18 orthopteran, 76 true bug and 20 rove beetle species were recorded in 138 surveyed kurgans (Deák et al, 2020). Besides being biodiversity hotspots in agricultural landscapes, kurgans can also 7 increase landscape-scale plant diversity in vast pristine steppes by harboring unique species confined exclusively to the special environmental conditions provided by the kurgans (Deák et al, 2017).…”