Located in the Maloti-Drakensberg Mountains of Lesotho, the Ha Makotoko rock shelter has been used by humans in southern Africa for approximately 60,000 years; inhabitants would sleep on grass beds, eat fish and mammals, and repair stone tools at the cave-like site. A team of researchers, led by Bryant University's Biological and Biomedical Sciences lecturer Robert Patalano, Ph.D., recently studied the rock shelter’s environmental and climate history — with published findings in Communications Earth & Environment.
In the study, researchers used plant wax biomarkers to show climatic and environmental changes directly related to human societies over the Late Pleistocene (61,000 to 26,000 years ago) and Holocene (11,000 to 1,000 years ago) ages. The collected data allowed the scholars to reconstruct changes in plant communities and variability in temperature and rainfall; this information helped to understand human-environment interactions in mountain ecosystems.
Since two-thirds of Lesotho is more than 2,000 meters above sea level, people living at Ha Makotoko would have encountered adaptive challenges to climate and ecological variability associated with the mountain systems, according to Patalano.
“The results demonstrate that climate, specifically precipitation and temperature, remained relatively stable across the Pleistocene and through much of the Holocene at Ha Makotoko,” says Patalano. “Only in the last 5,000 years were there drastic increases in rainfall and warming in western Lesotho.”
He adds that in the last 5,000 years there has been a big shift in human activity in the area. Instead of hunting and foraging, pastoralism dominated the last 1,000 years. Furthermore, in the last 200 years, wildebeests or zebras are no longer seen in that area even though they were abundant in the past.
Even though the data show that the Phuthiatsana River Valley — where the rock shelter is found — became warmer and wetter during the late Holocene, the Phuthiatsana Valley had reliable food and water resources for the people living in the region across most of the cooler, drier Pleistocene. This was extremely important for those living in the valley as the readily available resources there would have supported people during periods when nearby areas faced aridity and irregularly distributed resources.
Patalano says this research emphasizes the importance of consistent food and freshwater to continual human occupation of Lesotho and the wider Maloti-Drakensberg Mountain region. He adds that mountain systems probably played a greater role in human evolution during periods of climate or environmental stress which would have reduced available resources in lowland environments.
“The ability for past humans to access both the mountains and nearby plains through mobile foraging or social networking lends the Phuthiatsana Valley an ecotonal nature that would have enhanced its long-term stability for human populations by providing access to a wide variety of foods from both uplands and lowlands, and aquatic and terrestrial locations,” Patalano says.