Ancient plant provides key evidence of climate change in Peru

The oldest flowering plant specimen - and one of the recent additions to the herbarium in the Biology Collections at UConn - is providing a key piece of evidence in a scientific paper that documents a dramatic warming trend in the high Andes of Peru.

A 5,200-year-old plant specimen collected at the edge of an alpine glacier in Peru was identified by ecology and evolutionary biology professor Don Les as Distichia muscoides , a member of the rush family and a wetland plant.

The plant in effect "calibrates" the new study of tropical warming, Les says, showing that more than 5,000 years ago, an alpine glacier in Peru expanded quickly in a sudden cold period.

The study, published in June in the Proceedings of the National Academy of Sciences, shows an unprecedented warming trend in an alpine region of Peru for at least the past 2,000 years. Les was one of nine authors of the study, which was led by researchers at Ohio State University.

Three lines of evidence were used to document the warm-up: photographic records of a dramatic retreat of the Quelccaya glacier in the Andes during the period 1978 to 2000; a large increase in the amount of heavy oxygen in the ice cap during the years 1900 to 2000, which correlates with warmer conditions; and the presence of the plant identified by Les, which shows that the climate in the area was rapidly getting colder 5,000 years ago.

The ice had to move fast to cover the plant and preserve it, Les says. The rapid advance shows how quickly climate change can happen, he notes.

The ice layer flattened the plant, but it retained enough characteristics that Les, who is the director of the herbarium at UConn, was able to identify not only its genus, but its species, which is the only one found in alpine Peru.

The plant, which was radiocarbon-dated by a team of Ohio State University geologists leading the study, shows that boggy, wet conditions existed in the area before the glacier advanced.