Severe aridity during the mid-Holocene, ca. 8.0–4.0 kyr BP, led to extreme ecological stress in the tropical Andes. Here, we report paleolimnological and archeological data from Lake Suches in southern Peru (70° 24’ 12” W, 16° 55’ 35” S) spanning 13.6–4.4 kyr BP. Integrated paleoclimate and archeological data reveal that moisture was locally available and the basin served as an ecological refugium throughout the mid-Holocene. Mid-Holocene aridity was established no later than 7.2 kyr BP, with maximum aridity ca. 5.5–4.8 kyr BP. However, water levels in Lake Suches were sustained throughout peak middle-Holocene aridity, even as other systems desiccated. Isotopic enrichment of water in Lake Suches (δ 18 O lake ) and extensive wetlands (δ 18 O bofedal ) surrounding the lake indicate prolonged residence time. These reservoirs, combined with elevation-linked hydrographic factors, mitigated mid-Holocene net decreases in atmospheric moisture. Archeological data from Suches indicate successive population increases beginning ca. 11.0–9.8 kyr BP as drier but more stable early Holocene conditions were established regionally. Population maxima in Suches during the mid-Holocene/mid-Archaic period ca. 9.0–7.0 kyr BP coincide with peak aridity in the Titicaca and Atacama systems, as well as documented archeological hiatuses in these regions. Population decreases coincide with peak aridity recorded in Lake Suches ca. 6.0–5.0 kyr BP, but the basin was never fully abandoned. Evidence for refugial microenvironments is key to understanding the persistence of human populations and other endemic Andean flora and fauna during the highly adverse climates of the middle-Holocene. We outline several mechanisms which likely explain the formation of refugia linked to bofedales and hydrographic characteristics of Suches. Understanding refugial dynamics will be key to understanding the effects of past climatic change, as well as addressing current warming and decreased precipitation trends in the tropical Andes.
Bibliographical noteFunding Information:
We thank Alex Chepstow-Lusty, Mieke Stierken, Francesco Berna, Noa Corcoran-Tadd, and Kyle Stich for their assistance during the various stages of data collection and analysis. The ASTER L1B and SRTM data products were obtained through the online Reverb Data Pool at the NASA Land Processes Distributed Active Archive Center (LP DAAC), USGS/Earth Resources Observation and Science (EROS) Center, Sioux Falls, South Dakota. Precipitation data were accessed from the National Oceanic and Atmospheric Administration?s National Climate Data Center (NOAA-NCDC) and the United Nations World Meteorological Association (UN-WMO). Southern Copper Corporation provided access to Lake Suches, logistical support and climatic data. In particular, we thank Jos? de Pierola, C?sar Montes de Oca, and Hugo Valdiva at Southern Copper Corporation. La comunidades autonomas de Huaytire and Japopunco and individual land holders in the Suches region were key in supporting this fieldwork. Proxy analysis was conducted at the Sediment Geochemistry Laboratory at the University of Pittsburgh. Field and lab research was funded by the National Science Foundation (Grants BCS-0900904 to Vining, AGS-1137750 to Steinman, and the P2 C2 Program to Abbott) and a Douglas C. Kellogg Award for Geoarchaeological Research from the Society for American Archaeology (Vining).
Field and lab research was funded by the National Science Foundation (Grants BCS-0900904 to Vining, AGS-1137750 to Steinman, and the P2 C2 Program to Abbott) and a Douglas C. Kellogg Award for Geoarchaeological Research from the Society for American Archaeology (Vining).
© The Author(s) 2018.
- Archaic period archeology
- climate change
- mid-Holocene arid phase