Grantee Research Project Results
2002 Progress Report: Chinese Tallow Invasions into the Endangered Coastal Prairie: Causes and Consequences
EPA Grant Number: R828903Title: Chinese Tallow Invasions into the Endangered Coastal Prairie: Causes and Consequences
Investigators: Siemann, Evan , Grace, James , Rogers, William
Institution: Rice University
EPA Project Officer: Packard, Benjamin H
Project Period: June 1, 2001 through May 31, 2004 (Extended to May 31, 2005)
Project Period Covered by this Report: June 1, 2002 through May 31, 2003
Project Amount: $381,687
RFA: Exploratory Research to Anticipate Future Environmental Issues (2000) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Water , Aquatic Ecosystems
Objective:
The overall objective of this research project is to understand how abiotic conditions interact with biotic factors to influence the likelihood, severity, and impact of Chinese tallow tree (Sapium sebiferum) invasions into coastal prairie. The specific objectives of this research project are to address the following questions:
1. How do fire (annual or periodic), soil fertility, and herbivores interact to influence tallow tree invasion?
2. How do flooding, soil fertility, and herbivores interact to influence tallow tree invasion?
3. How important is local recruitment limitation versus local conditions in determining the likelihood and severity of tallow tree invasion?
Progress Summary:
The Chinese tallow tree is a major invader in the Southeast United States that aggressively displaces native plants. Our research will focus on the mechanisms that allow the tallow tree to become established in endangered coastal prairies and transform them into biotically depauperate forests.
Fire Experiment. We laid out this experiment and began the semiannual fertilization treatments in spring 2000. We burned the plots annually in 2000, 2001, 2002, and 2003. Another set of plots were burned only in 2000. The Sapium seed addition subexperiment was initiated in fall 1999 and spring 2000. We planted the Sapium seedlings in spring 2000. We harvested the Sapium seedlings in October 2002. We found strong facilitation of Sapium invasion by fertilization. Annual burns reduced Sapium invasion while the one-time burn has promoted invasion more than no burning at all. Woody invasion in general (responses of background vegetation) was limited by annual burning or a single burn compared to no burn. The Sapium appears to be unusually able to take advantage of opportunities created by the single burn event. Vegetation and soil samples for nutrient analysis were collected in 2003, and they will be processed for carbon and nitrogen content in late 2003 or early 2004.
Flood Experiment. In the original proposal, we described an experiment with a two-level water treatment (control versus flooded). We added another treatment in which water from extreme precipitation events is pumped out of the plots. The experimental design now addresses explicitly the range of variation that is present for the frequency of extreme precipitation events in the Gulf Coast in models of future climate. We laid out this experiment and began the semiannual fertilization treatments in spring 2002. At this time, we installed the water control structures and the subsurface pumps. We added Sapium seeds for the recruitment limitation experiment in spring 2002. We planted Sapium seedlings for the other subexperiment in spring 2002. Results through the second growing season show facilitation of Sapium invasion by fertilization. No overall significant effects of water manipulations occurred in the first growing season, but Sapium growth was inhibited in the drought plots compared to control plots in the second growing season. Based on the combination of survival and growth through Year 2 of the project, however, our results indicate that Sapium invasion is less intense in either extreme (wetter or drier) compared to ambient precipitation. This experiment will continue until late 2004 or early 2005.
Future Activities:
We will continue the fire (nutrient analyses and manuscript preparation) and flood experiments (field manipulations, nutrient analyses, and manuscript preparation) through the next reporting period.
Journal Articles:
No journal articles submitted with this report: View all 30 publications for this projectSupplemental Keywords:
animal, ecological effects, ecology, Gulf Coast, soil, prairie, tallgrass, tallgrass prairie, terrestrial, ecosystem protection, environmental exposure and risk, biology, chemical mixtures, human health, ecological indicators, ecological risk assessment, ecosystem, assessment, indicators, forestry, state, exploratory research, environmental biology, Chinese tallow, east Texas, TX, tallow tree invasions, abiotic, bioindicator, biopollution, carbon, ecological exposure, forest, futures, futures research, invasive plants, invasive species, nitrogen., RFA, Scientific Discipline, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Ecosystem/Assessment/Indicators, Ecosystem Protection, State, Forestry, Ecological Effects - Environmental Exposure & Risk, Ecological Risk Assessment, Ecology and Ecosystems, Exp. Research/future, Futures, bioindicator, ecological effects, ecological exposure, Tallow Tree invasions, forest, carbon, Texas, biopollution, East Texas, prairie, tall grass prairie, abiotic, exploratory research, Texas (TX), tallgrass, terrestrial, terrestrial habitat loss, invasive species, invasive plants, Chinese Tallow, futures researchRelevant Websites:
http://www.ruf.rice.edu/~siemann Exit
http://www.ruf.rice.edu/~ecology/ Exit
http://www.ruf.rice.edu/~ecology/insects/pics.html Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.