Soil charcoal elucidates the role of humans in the development of landscape of extreme biodiversity

Abstract

The south‐western White Carpathians (Czech Republic, Slovakia) are one of the few places in low‐elevation Central Europe where a diverse landscape, including extremely species rich meadows, scattered oak trees, and mixed oak woodlands, has escaped modern transformation. We studied C14‐dated and taxonomically identified macroscopic soil charcoal record to elucidate the genesis of this landscape. Thirteen soil profiles were sampled in grasslands along a gradient of elevation and history of human settlement. We identified clear pattern in the taxonomic composition of woody soil charcoal and anthracomass along this gradient, which we ascribe to different pathways of landscape development. Charcoal assemblages of chernozem‐like soils in the promontories of the mountain range have a low anthracomass and are dominated by heliophilous and semishade species (Quercus, Pinus), with the oldest charcoals dated to pre‐Neolithic times. Soils of the middle elevations have a high anthracomass and often show pronounced differences in charcoal composition at different soil depths; the oldest charcoal samples date back between the Neolithic and Early Middle Ages, and heliophilous species increase towards the topsoil. The soil of the summit area shows a medium anthracomass and charcoal assemblage dominated by shade‐tolerant trees; the charcoal dates from the Middle Ages. Our results suggest continuity of an open to semiopen landscape in lower elevations of the White Carpathians, whereas middle and higher elevations experienced a forested period. Humans and fire played an important role in landscape development, as indicated by both soil charcoal and available palaeoecological and archaeological evidence. Local meadows with extremely high biodiversity thus appear to be a continuation of an ancient forest‐steppe‐like ecosystem.

Soil moisture and a legacy of prehistoric human activities have contributed to the extraordinary plant species diversity of grasslands in the White Carpathians

“…Most often, pellic and luvic chernozems with conspicuously dark topsoil are recorded at low altitudes, while pellic, luvic, gleyic and sometimes skeletal cambisols, pararendzinas and luvisols at middle altitudes and in the northern part of the area studied (Sedláček 2012). The soils in the species-rich grasslands included in this study are deep (1 m or more) and show signs of translocation of clay, brunification and redoximorfism of varying intensity (Novák et al 2019).…”

“…Grasslands in the south-western part of the White Carpathians, where there are the most species and more forest-steppe species, may be considered, according to the classification of Feurdean et al (2018), as primary, ancient grasslands, maintained by climate and natural and later on anthropogenic disturbances. At low altitudes, grasslands have been continuously maintained since the pre-Neolithic times by natural or anthropogenic fires and grazing, whereas at middle and high altitudes grassland was intermixed with mainly oak woodlands (Novák et al 2019). The prehistoric management of these parklands and oak woodlands might include forest grazing, pollarding, shallow ploughing and burning.…”

“…Their occurrence hence provides an indication of continual existence of forest-steppe throughout the Holocene (Sillinger 1929, Hájková et al 2011. Another piece of evidence comes from palaeoecological reconstruction of a continuous persistence of open land throughout the most prominent phases of woodland expansion, either in the area studied (Hájková et al 2018, Novák et al 2019 or nearby (Kuneš et al 2015, Jamrichová et al 2017, and from archaeological records since the Neolithic in the south-western foothills of the White Carpathians (Hájková et al 2011). In contrast, palaeoecological evidence indicates that climax forests have been present in the central and north-eastern part of the White Carpathians since the Middle Holocene (Hájek et al 2016, Hájková et al 2018.…”

Holocene matters: Landscape history accounts for current species richness of vascular plants in forests and grasslands of eastern Central Europe

“…However, Holocene effects have been suggested as equally important. Some authors (Feurdean et al, ; Novák, Roleček, Dresler, & Hájek, ) explained the distribution of exceptionally species‐rich grasslands and open forests by the existence of Middle‐Holocene refugia of steppe grasslands. Palaeoecological studies indeed confirmed higher Middle‐Holocene representation of steppe grasslands in those regions where hotspots of grassland species richness occur today (Feurdean et al, ) in comparison to nearby regions with less species‐rich grasslands (Hájek et al, ; Jamrichová et al, ).…”

“…However, Holocene effects have been suggested as equally important. Some authors (Feurdean et al, 2018;Novák, Roleček, Dresler, & Hájek, 2019) (Feurdean et al, 2018) in comparison to nearby regions with less species-rich grasslands (Hájek et al, 2016;Jamrichová et al, 2017). Jamrichová et al (2017) also showed that the occurrence of rare species of boreal coniferous forests in the Western Carpathians coincides with the persistence of these forests during the Late-Holocene beech expansion.…”