Abstract Detail

Paleobotany

Green, Tom [1].

North Central Texas Holocene Plant Community Reconstruction.

Reconstructing plant community changes in response to climate during the Holocene provides a context to understand modern ecosystem resiliency. Previous palynological and isotopic studies provided evidence that the mid-Holocene of Texas experienced a significantly drier climate than today across North Central Texas. However, Holocene paleoenvironmental data for North Central Texas are limited and often difficult to correlate with other regions. Palynological data are useful for predicting how existing plant communities in Texas may adapt in response to persistent drought or intensified seasonality. This research provides new information on the vegetation communities of North Central Texas by evaluating microfossils at two separate localities: the Aubrey Site in Denton County and Gus Engeling Wildlife Management Area in Anderson County.
Phytoliths were extracted and analyzed from the Aubrey Site, which has a nearly continuous stratigraphy of radiometrically dated alluvial sediments ranging in age from the Late Pleistocene to the Late Holocene. Fossil alluvial and modern soil phytolith assemblages were analyzed and paleoenvironmental conditions were inferred to assess response to Holocene climate changes. The second locality, Gus Engeling Wildlife Management Area, protects a highly diverse flora including beakrush-pitcher plant communities associated with 300 acres of slightly acidic, organic-rich, spring-fed bogs. The palynological record from sediments at the bog margin was evaluated to determine plant community structure and its response to regional Holocene paleoclimate changes.
The phytolith record from the Aubrey Site indicates that at 1850 years BP, North Central Texas became more arid than in previous millennia and grasses expanded relative to woodlands; and mesic conditions returned by 1700 years BP. Paleoecological interpretations from phytoliths are complicated at Aubrey by a steadily decreasing fossil record with depth, which may limit their utility in addressing paleoenvironmental changes in the Late to Mid Holocene. The pollen record from sampled bog sediments at Gus Engeling Wildlife Management Area are incompletely preserved, but suggest resilient forest and wetland communities during the Holocene.

1 - 1600 Callaway Dr., Plano, TX, 75075, USA

Keywords:
climate
Holocene
Palynology
Phytolith
Pollen
Texas.

Presentation Type: Oral Paper
Session: 1, Cookson/Moseley award presentations
Location: Sundance 4/Omni Hotel
Date: Monday, June 26th, 2017
Time: 8:00 AM
Number: 1001
Abstract ID:320
Candidate for Awards:Isabel Cookson Award