Grazing activities in the southern central Pyrenees during the last millenium as deduced from the non-pollen palynomorphs (NPP) record of lake Montcortès

Abstract

Human activities during the last millennium have shaped most of the present-day landscapes. During this time, in the southern central Pyrenees several climate periods and phases of variable human disturbance have driven varied landscape responses. In previous studies of the sediment deposits in Lake Montcortès (southern central Pyrenees) several climatic shifts (including the Medieval Climate Anomaly and the Little Ice Age), as well as forest clearance by fire, agriculture and cattle raising as the main human impacts were recorded since Medieval times. In this work we use non-pollen palynomorphs (NPP) on the same sequence to reconstruct the different human activities, with a special focus on grazing, at an average resolution of around 30 years per sample. Independent NPP proxies for fire and forest clearance were found, supporting former studies. Moreover, the NPP record shows four periods of high abundance of coprophilous fungi: 1) 830-865 CE; 2) 1120-1290 CE; 3) 1530-1795 CE; and 4) 1865-1880 CE. These four periods correspond to phases of increased livestock farming, as reported in historical documents. Comparison of pollen, historical documents, and NPP records show that the impact on landscape dynamics during the last millennium have been mostly related to variable human population density controlled by historical, political and cultural changes in the Pyrenean mountains. Moreover, the use and comparison of several independent proxies have highlighted the strength of the indicator value obtained.