Summary: We used multiple variables in a sediment core from Lake Peten-Itza, Peten, Guatemala, to infer Holocene climate change and
human influence on the regional environment. Multiple proxies including pollen, stable isotope geochemistry, elemental composition,
and magnetic susceptibility in samples from the same core allow differentiation of natural versus anthropogenic environmental
changes. Core chronology is based on AMS 14C measurement of terrestrial wood and charcoal and thus avoids the vagaries of
hard-water-lake error. During the earliest Holocene, prior to ~9000 14C yr BP, the coring site was not covered by water and
all proxies suggest that climatic conditions were relatively dry. Water covered the coring site by ~9000 14C yr BP, coinciding
with filling of other lakes in Peten and farther north on the Yucatan Peninsula. During the early Holocene (~9000 to ~6800
14C yr BP), pollen data suggest moist conditions, but high delta 18O values are indicative of relatively high E/P. This apparent
discrepancy may be due to a greater fractional loss of the lake''s water budget to evaporation during the early stages of
lake filling. Nonetheless, conditions were moist enough to support semi-deciduous lowland forest. Decrease in delta 18O values
and associated change in ostracod species at ~6800 14C yr BP suggest a transition to even moister conditions. Decline in lowland
forest taxa beginning ~5780 14C yr BP may indicate early human disturbance. By ~2800 14C yr BP, Maya impact on the environment
is documented by accelerated forest clearance and associated soil erosion. Multiple proxies indicate forest recovery and soil
stabilization beginning ~1100 to 1000 14C yr BP, following the collapse of Classic Maya civilization.
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