Modern analogs for Pleistocene vegetation of the Yucatan Peninsula
Abstract
Vegetation dynamics in the Central American lowlands rapidly respond to global climatic variability. Fast response of the vegetation to external drivers at diverse time and spatial scales has been argued as one of the main mechanisms for the appearance of no modern analog vegetation. Thus, it is important to investigate the degree of analogy between modern and past communities. Some analogy has been found between vegetation that occupied the Petén-Itzá area (Guatemala) during the last glacial and modern vegetation of the adjacent highlands. However, little is known regarding vegetation from times further down in the past. The aim of our research is to evaluate the analogy of the vegetation revealed by the pollen record of Lake Petén-Itzá, and modern vegetation assemblages found today in the Yucatan Peninsula and Central Mexico. We use palynological evidence from core PI-7 with ages that go beyond 158,000 years BP (kyr) and compare it with modern pollen samples from diverse locations, as well as with fossil pollen from the last glacial. Minimum squared-chord distances of between 0.69 and 1.08 among samples older than 150 kyr and modern assemblages suggest the non existence of modern analogs for the vegetation that occupied the basin of Lake Petén-Itzá at that time. Similarly, distances among samples from the last glacial and those of before 150 kyr suggest little resemblance among assemblages, although they were less dissimilar (from 0.42 to 1.09). Higher distances between assemblages that are further apart in time are not surprising. However, there is still need to examine whether this pattern is the result of random processes or if there are underlying mechanisms that account for this long-term trend towards diverging community structure and composition.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2013
- Bibcode:
- 2013AGUSMGC43B..08B
- Keywords:
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- 0473 BIOGEOSCIENCES / Paleoclimatology and paleoceanography