Higher on the mountains: dynamics of agro-pastoral practices in a low-latitude mountain system (Karkas Mts, central Iran) during the Mediaeval Warm Period and Little Ice Age

Little is known about the impact of the Mediaeval Warm Period (MWP: 950-1250 CE) and the Little Ice Age (LIA: 1250-1850 CE) on high-altitude agro-pastoral practices and the vertical mobility of human communities in the mountain regions of interior Southwest Asia. Although the area experienced significant socio-political changes during the last millennium, the socio-environmental interactions during these climatic periods remain poorly understood. This study presents a geochronologically well-constrained, multi-proxy geochemical and palaeoecological record from a high-altitude (2500 m) wetland in the Karkas Mountains, located on the central Iranian desert plateau. All proxies, including bioindicators (pollen, non-pollen palynomorphs, fossil insects) and X-ray fluorescence (XRF) intensity variations, reveal two contrasting patterns of hydroclimatic conditions and agro-pastoral practices during the MWP and the LIA. While the MWP is characterised by intensive cereal cultivation and the probable establishment of permanent agricultural communities, the LIA shows intensified grazing pressure on mountain steppe vegetation, suggesting a shift towards a more mobile pastoral lifestyle—one that persisted into the 20th century. Interestingly, this shift coincides with the Mongol invasion of the Iranian plateau, though it may not necessarily be related to it. Based on the Gahak wetland record and regional palaeoclimatic data, we conclude that the MWP in the mountainous areas of central Iran was marked by milder winters and possibly shorter summer droughts, in contrast to the LIA, which had harsher winters and longer-lasting snow cover. Our findings highlight the significant role of high-altitude agro-pastoral communities in supplying food to the lowland urban centres of mediaeval Persia, at least during the MWP.