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osu1233264311.pdf (1.21 MB)
ETD Abstract Container
Abstract Header
Effects of the spatial heterogeneity formed by
Ambrosia dumosa
on individual and population growth of the invasive grass
Schismus barbatus
Author Info
Rodriguez-Buritica, Susana
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1233264311
Abstract Details
Year and Degree
2009, Doctor of Philosophy, Ohio State University, Evolution, Ecology, and Organismal Biology.
Abstract
Natural ecosystems are exposed to numerous factors that determine their structure and dynamics. Although change is typically inherent in to biological systems, very few factors change a natural ecosystem as drastically as the arrival and successful establishment of non-native species. The impact of the Mediterranean grass (
Schismus barbatus
) in the southwestern U.S. exemplifies such dynamics. In my dissertation, I empirically and theoretically explore two components of
Schismus
invasion. First, native shrubs may promote
Schismus
invasion if
Schismus
benefits from the favorable growth conditions that shrubs provide. Second,
Schismus
may threaten ecosystem level properties if
Schismus
precludes establishment of shrubs. Thus
Schismus
may compromise the maintenance of Islands of fertility that favor growth of native plant community. To meet these objectives, I explore
Schismus
performance with respect to the location and size of one of the most abundant native shrubs in the Sonoran and Mojave Deserts, the Bur-sage shrub,
Ambrosia dumosa
. As a first approximation to the study system, I describe the natural distribution of
Schismus
with respect to the location of native shrubs (Chapter 1). Then, I examine factors that control
Schismus-Ambrosia
interaction using a three-year field experiment (Chapter 2), and subsequent characterization of soil nutrients changes around
Ambrosia
shrubs in the context of
Schismus
invasion (Chapter 3). I found that
Schismus barbatus
responds to the spatial heterogeneity formed by
Ambrosia
. This response is strongly controlled by water availability (Chapters 1 and 2).
Ambrosia
creates a dichotomous landscape formed by nutrient rich areas below their canopies and nutrient poor areas at inter-shrub spaces (Chapter 2). In this landscape, performance of
Schismus
is favored around
Ambrosia
during years with good precipitation. Nevertheless, at any given growing season, shading and water interception by shrub canopies are the most influential factors on
Schismus
performance. Given that germination was consistently low below Ambrosia canopies, the consequences of
Schismus-Ambrosia
interactions might not be as straightforward as predicted by the individual effect of Ambrosia on
Schismus
. In fact,
Ambrosia
might actually reduce realized
Schismus
densities. Conversely, inter-specific competition with
Schismus
regulates
Ambrosia
seedling survival. Thus, high-density stands of
Schismus
might generate a negative feedback on the dynamics of favorable areas associated with shrubs; ultimately limiting
Schismus
abundance. I design a modeling framework to test this hypothesis and present several predictions about the long-term demographic consequences of reciprocal interactions between
Schismus
and
Ambrosia
(Chapter 4).
Committee
Maria Miriti, Dr. (Advisor)
Ralph Boerner, Dr. (Committee Member)
Elizabeth Marschall, Dr. (Committee Member)
Karen Goodell, Dr. (Committee Member)
Pages
168 p.
Subject Headings
Ecology
Keywords
Invasive species
;
demography
;
spatial heterogeneity
;
Islands of fertility
;
Schismus barbatus
;
Ambrosia dumosa
;
Desert ecology
Recommended Citations
Refworks
EndNote
RIS
Mendeley
Citations
Rodriguez-Buritica, S. (2009).
Effects of the spatial heterogeneity formed by
Ambrosia dumosa
on individual and population growth of the invasive grass
Schismus barbatus
[Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1233264311
APA Style (7th edition)
Rodriguez-Buritica, Susana.
Effects of the spatial heterogeneity formed by
Ambrosia dumosa
on individual and population growth of the invasive grass
Schismus barbatus
.
2009. Ohio State University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1233264311.
MLA Style (8th edition)
Rodriguez-Buritica, Susana. "Effects of the spatial heterogeneity formed by
Ambrosia dumosa
on individual and population growth of the invasive grass
Schismus barbatus
." Doctoral dissertation, Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1233264311
Chicago Manual of Style (17th edition)
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Document number:
osu1233264311
Download Count:
1,268
Copyright Info
© 2009, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.