Recent Topics Posters
Van Kley, James , Cahal, Joshua , Hinchliffe, Taylor , Prewitt, Morgan , Melvin, Jarrod .
Observing Impacts of the 2011 Drought in Three east Texas Plant Communities Using Undergraduate Research Projects.
The summer of 2011 was the hottest and driest on record in Texas history. Three contrasting plant communities in the east Texas Pineywoods region were sampled to observe impacts of the drought. In a a pine-oak-sweetgum forest on a dry-mesic upland, belt transects comprised of adjacent 20x 50m plots were used to record all dead tress and compare recent mortality levels with trees dead prior to 2011. Line transects were established in two rare herbaceous seep communities and the condition of each intercepted colony of pitcher plants (Saracennia alata) compared with soil moisture levels. Permanent sample points in a bald cypress (Taxodium distichum) -dominated wetland complex associated with Caddo Lake in northeastern Texas were revisited and 2011 surface layer species composition compared with that observed during previous years using multivariate analysis. Significantly higher levels of tree mortality occurred in the upland forest in 2011 than in the previous 7 years and more pines as a proportion of total basal area died than hardwoods-supporting widespread observations of massive tree death in Texas during 2011. In the herbaceous seeps, pitcher plant health was positively correlated with soil moisture and the hydration of associated Sphagnum mosses. While much of the Sarracenia population was damaged, healthy plants were present where spring seepage still occurred; heterogeneity within the wetland may enhance the ability of populations to survive extreme events. At Caddo Lake, CCA results indicated that year-to-year differences in species composition were partially related to summer low water levels and that substrate-rooted species increased at the expense of floating and submersed species during dry years such as 2011. This study enabled us to observe how both wetland and upland ecosystems responded to the 2011 drought. Each element of the study was contributed by a separate one-semester undergraduate research project, providing a model of how undergraduate research can contribute to an ongoing long term faculty and graduate-level research program.
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1 - Stephen F. Austin State University, Biology, PO Box 13003, Nacogdoches, TX, 75962, USA
Presentation Type: Recent Topics Poster
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM