Andean landscapes are regarded as “manufactured” considering the impact of modern, pre-European, and pre-Columbian societies particularly over the last three millennial. The earliest evidence of human occupation for high Andes (>4000 m) dates back to 12,800 years BP, however, it cannot be assumed that Andean ecosystems became anthropogenic instantaneously. Although humans were capable of impacting paleo-landscapes, namely through the use of fire, the actual effects on the vegetation are seldom verified.
Pollen records derived from 13 Andean sites were used to determine (i) if high Andean woodlands became decoupled from the climatic influence immediately after the human incursion in the Andes, and (ii) was the current patchy distribution of modern high Andean woodlands commonplace prior human incursion. Detrended correspondence analyses of pollen assemblages from Lakes Miski, Huamanmarca and Pacucha were used to identify if “natural” assemblages, i.e. ecological baselines, can be found in the Holocene and, if such ecological baselines can be used for restoring long-term human disturbed Andean ecosystems.
Results/Conclusions
Our analyses show that high Andean woodlands were patchy and constrained by precipitation and glacier expansion prior to human incursion in the Andes. The trajectories of vegetation change from Lakes Miski and Huamanmarca suggest that landscapes became anthropogenic and decoupled from climate between 8000 and 7000 years ago. Moreover, ecological baselines can be sought within the Holocene but cannot be expected to reach stability as they are influenced by ever changing climate, biotic and stochastic processes. Consequently restoration of disturbed sites should aim for a range of assemblages rather than any fixed composition.