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Feedbacks of nitrogen cycling and in...

Duke University., Environment.

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Feedbacks of nitrogen cycling and invasion with the non-native plant, Microstegium vimineum, in riparian wetlands.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Feedbacks of nitrogen cycling and invasion with the non-native plant, Microstegium vimineum, in riparian wetlands./
Author:	DeMeester, Julie Elizabeth.
Description:	135 p.
Notes:	Adviser: Daniel D. Richter.
Contained By:	Dissertation Abstracts International70-03B.
Subject:	Biogeochemistry. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3352314
ISBN:	9781109089202

Feedbacks of nitrogen cycling and invasion with the non-native plant, Microstegium vimineum, in riparian wetlands.
DeMeester, Julie Elizabeth.

Feedbacks of nitrogen cycling and invasion with the non-native plant, Microstegium vimineum, in riparian wetlands. - 135 p.

Adviser: Daniel D. Richter.

Thesis (Ph.D.)--Duke University, 2009.

Invasive species are rapidly expanding in riparian wetlands while concurrently anthropogenic causes are increasing nitrogen (N) into these ecosystems. Microstegium vimineum (Microstegium) is a particularly abundant invasive grass in the Southeast United States. To evaluate impacts of Microstegium on both plant diversity and N cycling in a riparian floodplain, paired plots of Microstegium hand-weeded and unweeded were established for three years. Plots without Microstegium increased from 4 to 15 species m-2 and 90% of the newly establishing species were native. The Microstegium community accumulated approximately half the annual N in biomass of the diverse community, 5.04 versus 9.36 g-N m-2 year-1, respectively (p=0.05). Decomposition and release of N from Microstegium detritus was much less than in the diverse community, 1.19 versus 5.24 g-N m-2 year-1. Rates of soil N mineralization estimated by in-situ incubations were relatively similar in all plots. While Microstegium invasion appears to greatly diminish within-ecosystem circulation of N through the under-story plants, it might increase ecosystem N losses through enhanced denitrification (due to lower redox potentials under Microstegium plots). Microstegium removal ceased in the fourth growing season and formerly weeded plots increased to 59% (+/- 11% SE) Microstegium cover and species richness decreased to <8 species m-2.

ISBN: 9781109089202Subjects--Topical Terms:

545717
Biogeochemistry.

Feedbacks of nitrogen cycling and invasion with the non-native plant, Microstegium vimineum, in riparian wetlands.
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020 $a 9781109089202
035 $a (UMI)AAI3352314
035 $a AAI3352314
040 $a UMI $c UMI
100 1 $a DeMeester, Julie Elizabeth. $3 1030291
245 1 0 $a Feedbacks of nitrogen cycling and invasion with the non-native plant, Microstegium vimineum, in riparian wetlands.
300 $a 135 p.
500 $a Adviser: Daniel D. Richter.
500 $a Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1433.
502 $a Thesis (Ph.D.)--Duke University, 2009.
520 $a Invasive species are rapidly expanding in riparian wetlands while concurrently anthropogenic causes are increasing nitrogen (N) into these ecosystems. Microstegium vimineum (Microstegium) is a particularly abundant invasive grass in the Southeast United States. To evaluate impacts of Microstegium on both plant diversity and N cycling in a riparian floodplain, paired plots of Microstegium hand-weeded and unweeded were established for three years. Plots without Microstegium increased from 4 to 15 species m-2 and 90% of the newly establishing species were native. The Microstegium community accumulated approximately half the annual N in biomass of the diverse community, 5.04 versus 9.36 g-N m-2 year-1, respectively (p=0.05). Decomposition and release of N from Microstegium detritus was much less than in the diverse community, 1.19 versus 5.24 g-N m-2 year-1. Rates of soil N mineralization estimated by in-situ incubations were relatively similar in all plots. While Microstegium invasion appears to greatly diminish within-ecosystem circulation of N through the under-story plants, it might increase ecosystem N losses through enhanced denitrification (due to lower redox potentials under Microstegium plots). Microstegium removal ceased in the fourth growing season and formerly weeded plots increased to 59% (+/- 11% SE) Microstegium cover and species richness decreased to <8 species m-2.
520 $a To learn how Microstegium responds to increased N, we conducted a greenhouse competition experiment between Microstegium and four native plants across an N gradient. There was a unique competition outcome in each species combination, yet Microstegium was most dominant in the high levels of N.
520 $a Last, we disturbed a floodplain similar to wetland restoration disturbance and tracked available N. We also established a native community of plants with and without Microstegium in three levels of N. Disturbance to the floodplain dramatically increased inorganic N, especially in the form of NO3 which was five times higher in the disturbed floodplain than the undisturbed floodplain. N levels remained elevated for over a year. Microstegium was N responsive, but did not show negative effects to the planted vegetation until the second year. Ironically, restoration activities are increasing available N, and favoring invasive species which in turn detracts from restoration success.
590 $a School code: 0066.
650 4 $a Biogeochemistry. $3 545717
650 4 $a Biology, Ecology. $3 1017726
650 4 $a Environmental Sciences. $3 676987
690 $a 0329
690 $a 0425
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710 2 $a Duke University. $b Environment. $3 1018684
773 0 $t Dissertation Abstracts International $g 70-03B.
790 $a 0066
790 1 0 $a Bernhardt, Emily S. $e committee member
790 1 0 $a Christensen, Norman L. $e committee member
790 1 0 $a Reid, Chantal D. $e committee member
790 1 0 $a Richter, Daniel D., $e advisor
790 1 0 $a Wright, Justin P. $e committee member
791 $a Ph.D.
792 $a 2009
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3352314