Author : Elizabeth Cayenne Engel
Publisher :
ISBN 13 :
Total Pages : 94 pages
Book Rating : 4.:/5 (635 download)
Book Synopsis Old-field Community Response to Multiple Interacting Factors of Global Change by : Elizabeth Cayenne Engel
Download or read book Old-field Community Response to Multiple Interacting Factors of Global Change written by Elizabeth Cayenne Engel and published by . This book was released on 2005 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Communities are structured by many factors including abiotic factors such as resource availability, and biotic interactions. Climatic and atmospheric change will affect the composition of plant communities through multiple interacting biotic and abiotic factors. Literature on the effects of single factors on plant communities is abundant yet there have been few experiments examining the effects of multiple abiotic factors associated with climate change. Moreover, plant communities are not controlled solely by environmental conditions, but by biotic interactions such as competition and facilitation. In this thesis, I used a field experiment to examine the effects of elevated [CO2], warming, and soil moisture on in-situ old-field plant communities (Chapter 2). In addition, I conducted a separate field experiment to examine the competitive relationships among the constituent species to test whether an experimentally derived competitive hierarchy can predict relative abundances of species within plant communities (Chapter 3). I examined plant community responses to treatments of elevated [CO2] (+300 ppm), warming (+3 degrees C), and soil moisture availability applied to experimental plots within open-top chambers at Oak Ridge National Laboratory. In 2002, we constructed plots with plant communities consisting of seven common old-field species, including grasses, forbs, and legumes. Beginning in 2003, we tracked foliar cover, density and recruitment, and reproductive phenology for each plant species, and determined changes in community diversity and evenness over the course of two growing seasons. We observed few interactive effects of treatments on plant abundance. Most of the observed plant responses to treatments were responses to single factors. Species-specific foliar cover was most strongly influenced by warming: warming reduced foliar cover of Trifolium pratense and Dactylis glomerata, but increased foliar cover of Andropogon virginicus and Solidgao canadensis. Foliar cover of Dactylis glomerata was lower in dry plots than in wet plots. During the second full growing season, plant species diversity, evenness, and richness were at least 10% lower in wet plots, where total foliar cover and dominance were greater than in dry plots. Interactive effects of treatments appeared only toward the end of the second growing season. For example, late in the growing season of 2004, cover of Dactylis was four times greater within wet plots under ambient temperatures than in all other treatment combinations (temperature x water interaction; P less than 0.02).