Matching Items (17)
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- All Subjects: Ecology
- All Subjects: carbon cycling
- Genre: Masters Thesis
- Creators: Makings, Elizabeth
- Creators: Hall, Sharon J
Description
Stream flow permanence plays a critical role in determining floristic composition, abundance, and diversity in the Sonoran Desert, but questions remain about the effects of stream flow permanence on butterfly composition, abundance, and diversity. Understanding the effects of flow permanence on butterflies and relevant subsets of butterflies (such as butterflies whose host plants are present) and comparing them to these same effects on plants and relevant subsets of plants (such as butterfly nectar plants and larval host plants) provided insight into pollinator and riparian conservation and restoration.
I surveyed four Sonoran desert stream sites, and found significant relationships between flow permanence and plant and butterfly species richness and abundance, as well as strong relationships between plant and butterfly abundance and between plant and butterfly species richness. Most notably, my results pointed to hosted butterflies as a break-out category of butterflies which may more clearly delineate ecological relationships between butterfly and plant abundance and diversity along Sonoran Desert streams; this can inform conservation decisions. Managing for hosted (resident) butterflies will necessarily entail managing for the presence of surface water, nectar forage, varying levels of canopy cover, and plant, nectar plant, and host plant diversity since the relationships between hosted butterfly species richness and/or abundance and all of these variables were significant, both statistically and ecologically.
I surveyed four Sonoran desert stream sites, and found significant relationships between flow permanence and plant and butterfly species richness and abundance, as well as strong relationships between plant and butterfly abundance and between plant and butterfly species richness. Most notably, my results pointed to hosted butterflies as a break-out category of butterflies which may more clearly delineate ecological relationships between butterfly and plant abundance and diversity along Sonoran Desert streams; this can inform conservation decisions. Managing for hosted (resident) butterflies will necessarily entail managing for the presence of surface water, nectar forage, varying levels of canopy cover, and plant, nectar plant, and host plant diversity since the relationships between hosted butterfly species richness and/or abundance and all of these variables were significant, both statistically and ecologically.
ContributorsButler, Lane (Author) / Stromberg, Juliet C. (Thesis advisor) / Makings, Elizabeth (Committee member) / Pearson, David L (Committee member) / Boggess, May (Committee member) / Buchmann, Stephen (Committee member) / Arizona State University (Publisher)
Created2015
Description
The Upper Verde River of central Arizona flows through a landscape of complex geology at the meeting of seven biotic communities and three physiographic provinces. This has resulted in notably diverse flora and fauna and a hub of rare and endemic plant species. The river has sustained cultures since pre-history, however current regional water use is predicted to diminish streamflow over the next century. Prior to this project, no floristic inventory had been conducted along any section of the Verde. The purpose of this study was to develop a Flora of the Upper Verde River, with the goals of documenting rare and endemic species, the composition and abundance of wetland plants, and the factors shaping plant diversity in the region.
I made a total of 1856 collections and reviewed past collections to produce a checklist of 729 vascular plant taxa in 403 genera and 98 families. The most species-rich family is the Poaceae, followed by Asteraceae and Fabaceae. The flora includes 159 wetland taxa, 47 endemics, and 26 taxa of conservation concern, eight of which are Federally listed. Several new populations were found in these categories and of rarely-collected taxa including one state record, three county records and several range extensions. I report on the local status of several endemics, wetland taxa with limited distributions, and relict populations of a tepary bean (Phaseolus acutifolius) that were likely transported to the region and cultivated by pre-Columbian cultures. I categorize thirteen distinct plant communities, the most abundant being Pinyon/Juniper Woodland, Chihuahuan/Apacherian Scrub, and Riparian Deciduous Forest.
Four primary factors influence floristic diversity of the Upper Verde region: 1) a location at the junction of three physiographic and floristic provinces—represented by co-occurrence of species with affinities to the Sonoran, Intermountain and Madrean regions, 2) geologic diversity—as distinct groups of species are associated with particular geologic types, 3) topographic and habitat complexity—allowing species adapted to disparate environments to co-occur, and 4) human introductions—since over 15% of the flora is composed of introduced species from Eurasia and several taxa were introduced to the region and cultivated by pre-Columbian cultures.
I made a total of 1856 collections and reviewed past collections to produce a checklist of 729 vascular plant taxa in 403 genera and 98 families. The most species-rich family is the Poaceae, followed by Asteraceae and Fabaceae. The flora includes 159 wetland taxa, 47 endemics, and 26 taxa of conservation concern, eight of which are Federally listed. Several new populations were found in these categories and of rarely-collected taxa including one state record, three county records and several range extensions. I report on the local status of several endemics, wetland taxa with limited distributions, and relict populations of a tepary bean (Phaseolus acutifolius) that were likely transported to the region and cultivated by pre-Columbian cultures. I categorize thirteen distinct plant communities, the most abundant being Pinyon/Juniper Woodland, Chihuahuan/Apacherian Scrub, and Riparian Deciduous Forest.
Four primary factors influence floristic diversity of the Upper Verde region: 1) a location at the junction of three physiographic and floristic provinces—represented by co-occurrence of species with affinities to the Sonoran, Intermountain and Madrean regions, 2) geologic diversity—as distinct groups of species are associated with particular geologic types, 3) topographic and habitat complexity—allowing species adapted to disparate environments to co-occur, and 4) human introductions—since over 15% of the flora is composed of introduced species from Eurasia and several taxa were introduced to the region and cultivated by pre-Columbian cultures.
ContributorsCoburn, Francis S (Author) / Stromberg, Juliet C. (Thesis advisor) / Landrum, Leslie R (Thesis advisor) / Makings, Elizabeth (Committee member) / Fertig, Walter F (Committee member) / Arizona State University (Publisher)
Created2015
Description
Baseline community composition data provides a snapshot in time that allows changes in composition to be monitored more effectively and can inform best practices. This study examines Arizona Upland plant community composition of the Sonoran Desert through three different lenses: floristic inventory, and fire and reseeding effects.
A floristic inventory was conducted at Cave Creek Regional Park (CCRP), Maricopa County, AZ. One hundred fifty-four taxa were documented within Park boundaries, including 148 species and six infraspecific taxa in 43 families. Asteraceae, Boraginaceae, and Fabaceae accounted for 40% of documented species and annuals accounted for 56% of documented diversity.
Fire effects were studied at three locations within McDowell Sonoran Preserve (MSP), Scottsdale, AZ. These fires occurred throughout the 1990s and recovered naturally. Fire and reseeding effects were studied at the site of a 2005 fire within CCRP that was reseeded immediately following the fire.
Two questions underlie the study regarding fire and reseeding effects: 1) How did fire and reseeding affect the cover and diversity of the plant communities? 2) Is there a difference in distribution of cover between treatments for individual species or growth habits? To address these questions, I compared burned and adjacent unburned treatments at each site, with an additional reseeded treatment added at CCRP.
MSP sites revealed overall diversity and cover was similar between treatments, but succulent cover was significantly reduced, and subshrub cover was significantly greater in the burn treatment. Seventeen species showed significant difference in distribution of cover between treatments.
The CCRP reseeded site revealed 11 of 28 species used in the seed mix persist 12 years post-fire. The reseeded treatment showed greater overall diversity than burned and unburned treatments. Succulent and shrub cover were significantly reduced by fire while subshrub cover was significantly greater in the reseeded treatment. Sixteen species showed significant difference in distribution of cover between treatments.
Fire appears to impact plant community composition across Arizona Upland sites. Choosing species to include in seed mixes for post-fire reseeding, based on knowledge of pre-fire species composition and individual species’ fire responses, may be a useful tool to promote post-fire plant community recovery.
A floristic inventory was conducted at Cave Creek Regional Park (CCRP), Maricopa County, AZ. One hundred fifty-four taxa were documented within Park boundaries, including 148 species and six infraspecific taxa in 43 families. Asteraceae, Boraginaceae, and Fabaceae accounted for 40% of documented species and annuals accounted for 56% of documented diversity.
Fire effects were studied at three locations within McDowell Sonoran Preserve (MSP), Scottsdale, AZ. These fires occurred throughout the 1990s and recovered naturally. Fire and reseeding effects were studied at the site of a 2005 fire within CCRP that was reseeded immediately following the fire.
Two questions underlie the study regarding fire and reseeding effects: 1) How did fire and reseeding affect the cover and diversity of the plant communities? 2) Is there a difference in distribution of cover between treatments for individual species or growth habits? To address these questions, I compared burned and adjacent unburned treatments at each site, with an additional reseeded treatment added at CCRP.
MSP sites revealed overall diversity and cover was similar between treatments, but succulent cover was significantly reduced, and subshrub cover was significantly greater in the burn treatment. Seventeen species showed significant difference in distribution of cover between treatments.
The CCRP reseeded site revealed 11 of 28 species used in the seed mix persist 12 years post-fire. The reseeded treatment showed greater overall diversity than burned and unburned treatments. Succulent and shrub cover were significantly reduced by fire while subshrub cover was significantly greater in the reseeded treatment. Sixteen species showed significant difference in distribution of cover between treatments.
Fire appears to impact plant community composition across Arizona Upland sites. Choosing species to include in seed mixes for post-fire reseeding, based on knowledge of pre-fire species composition and individual species’ fire responses, may be a useful tool to promote post-fire plant community recovery.
ContributorsBarron, Kara Lynn (Author) / Pigg, Kathleen B (Thesis advisor) / Stromberg, Juliet (Thesis advisor) / Makings, Elizabeth (Committee member) / McCue, Kimberlie (Committee member) / Arizona State University (Publisher)
Created2018
Description
Dissolved organic matter (DOM) is an important part of aquatic foodwebs because it contains carbon, nitrogen, and other elements required by heterotrophic organisms. It has many sources that determine its molecular composition, nutrient content, and biological lability and in turn, influence whether it is retained and processed in the stream reach or exported downstream. I examined the composition of DOM from vascular wetland plants, filamentous algae, and riparian tree leaf litter in Sonoran Desert streams and its decomposition by stream microbes. I used a combination of field observations, in-situ experiments, and a manipulative laboratory incubation to test (1) how dominant primary producers influence DOM chemical composition and ecosystem metabolism at the reach scale and (2) how DOM composition and nitrogen (N) content control microbial decomposition and stream uptake of DOM. I found that differences in streamwater DOM composition between two distinct reaches of Sycamore Creek did not affect in-situ stream respiration and gross primary production rates. Stream sediment microbial respiration rates did not differ significantly when incubated in the laboratory with DOM from wetland plants, algae, and leaf litter, thus all sources were similarly labile. However, whole-stream uptake of DOM increased from leaf to algal to wetland plant leachate. Desert streams have the potential to process DOM from leaf, wetland, and algal sources, though algal and wetland DOM, due to their more labile composition, can be more readily retained and mineralized.
ContributorsKemmitt, Kathrine (Author) / Grimm, Nancy (Thesis advisor) / Hartnett, Hilairy (Committee member) / Throop, Heather (Committee member) / Arizona State University (Publisher)
Created2018
Description
As a result of growing populations and uncertain resource availability, urban areas are facing pressure from federal and state agencies, as well as residents, to promote conservation programs that provide services for people and mitigate environmental harm. Current strategies in US cities aim to reduce the impact of municipal and household resource use, including programs to promote water conservation. One common conservation program incentivizes the replacement of water-intensive turfgrass lawns with landscapes that use less water consisting of interspersed drought-tolerant shrubs and trees with rock or mulch groundcover (e.g. xeriscapes, rain gardens, water-wise landscapes). A handful of previous studies in experimental landscapes have shown that converting a turfgrass yard to a shrub-dominated landscape has the potential to increase rates of nitrate (NO3-) leaching. However, no studies have examined the drivers or patterns across diverse management practices. In this research, I compared soil nutrient retention and cycling in turfgrass and lawn-alternative xeriscaped yards along a chronosequence of time since land cover change in Tempe, Arizona, in the semi-arid US Southwest. Soil inorganic extractable nitrogen (N) pools were greater in xeriscapes compared to turfgrass lawns. On average xeriscapes contained 2.5±0.4 g NO3--N/m2 in the first 45 cm of soil, compared to 0.6±0.7 g NO3--N/m2 in lawns. Soil NO3--N pools in xeriscaped yards also varied significantly with time: pools were largest 9-13 years after cover change and declined to levels comparable to turfgrass at 18-21 years. Variation in soil extractable NO3--N with landscape age was strongly influenced by management practices that control soil water availability, including shrub cover, the presence of sub-surface plastic sheeting, and the frequency of irrigation. This research is the first to explore the ecological outcomes and temporal dynamics of an increasingly common, ‘sustainable’ land use practice that is universally promoted in US cities. Our findings show that transitioning from turfgrass to water-efficient residential landscaping can lead to an accumulation of NO3--N that may be lost from the soil rooting zone over time, through leaching following irrigation or rainfall. These results have implications for best management practices to optimize the benefits of water-conserving residential yards.
ContributorsHeavenrich, Hannah (Author) / Hall, Sharon J (Thesis advisor) / Larson, Kelli L (Committee member) / Potaki, Diane E (Committee member) / Arizona State University (Publisher)
Created2015
Description
It’s no secret that wetlands have dramatically declined in the arid and semiarid American West, yet the small number of wetlands that persist provide vital ecosystem services. Ciénega is a term that refers to a freshwater arid-land wetland. Today, even in areas where ciénegas are prominent they occupy less than 0.1% of the landscape. This investigation assesses the distribution of vascular plant species within and among ciénegas and address linkages between environmental factors and wetland plant communities. Specifically, I ask: 1) What is the range of variability among ciénegas, with respect to wetland area, soil organic matter, plant species richness, and species composition? 2) How is plant species richness influenced locally by soil moisture, soil salinity, and canopy cover, and regionally by elevation, flow gradient (percent slope), and temporally by season? And 3) Within ciénegas, how do soil moisture, soil salinity, and canopy cover influence plant species community composition? To answer these questions I measured environmental variables and quantified vegetation at six cienegas within the Santa Cruz Watershed in southern Arizona over one spring and two post-monsoon periods. Ciénegas are highly variable with respect to wetland area, soil organic matter, plant species richness, and species composition. Therefore, it is important to conserve the ciénega landscape as opposed to conserving a single ciénega. Plant species richness is influenced negatively by soil moisture, positively by soil salinity, elevation, and flow gradient (percent slope), and is greater during the post-monsoon season. Despite concerns about woody plant encroachment reducing biodiversity, my investigation suggests canopy cover has no significant influence on ciénega species richness. Plant species community composition is structured by water availability at all ciénegas, which is consistent with the key role water availability plays in arid and semiarid regions. Effects of canopy and salinity structuring community composition are site specific. My investigation has laid the groundwork for ciénega conservation by providing baseline information of the ecology of these unique and threatened systems. The high variability of ciénega wetlands and the rare species they harbor combined with the numerous threats against them and their isolated occurrences makes these vanishing communities high priority for conservation.
ContributorsWolkis, Dustin (Author) / Stromberg, Juliet C. (Thesis advisor) / Hall, Sharon (Committee member) / Salywon, Andrew (Committee member) / Makings, Elizabeth (Committee member) / Arizona State University (Publisher)
Created2016
Description
The spread of dengue worldwide currently places half of the world’s population at risk. In the absence of a dengue vaccine, control of the disease requires control of the mosquito species that transmit the virus. The most important of these is. Advances in research detailing the responsiveness of Aedes aegypti to small changes in climate enable the production of more sophisticated remote sensing and surveillance techniques for monitoring these populations. Close monitoring of global dengue activity and outbreaks likewise enables a greater specificity when determining to which human populations the virus is most likely to spread. There have been no locally acquired cases in Arizona to date, but the high abundance of Aedes aegypti in the Phoenix Metropolitan area raises concern within the Arizona Department of Health Services over the potential transmission of dengue in the city. This study develops a model that combines mosquito abundance, micro-climatic and demographic information to delineate regions in Phoenix that are most support transmission of dengue. The first chapter focuses on the impact that daytime high and low temperatures have on Aedes aegypti’s ability to become infectious with dengue. It argues that NDVI (normal difference vegetative index) imaging of the Phoenix area can be used to plot areas where mosquitoes are most likely to become competent vectors. The second chapter focuses on the areas in the city where mosquitoes are most likely to be exposed to the virus. Based on proximity to Phoenix and the high volume of traffic across the Arizona-Mexico border, I treat the Mexican state of Sonora as the source of infection. I combine these two analyses, micro-climatic and demographic, to produce maps of Phoenix that show the locations with the highest likelihood of transmission overall.
ContributorsHughes, Tyler (Author) / Perrings, Charles (Thesis advisor) / Kinzig, Ann (Committee member) / Hall, Sharon J (Committee member) / Arizona State University (Publisher)
Created2016
Description
As an industrial society, humans have increasingly separated agricultural processes from natural ecosystems. Many areas of the Southwestern US, however, maintain traditional practices that link agricultural systems to the natural environment. One such practice, diverting river water into fields via earthen irrigation canals, allows ditch water to recharge groundwater and riparian vegetation to prosper along canal banks. As there is growing interest in managing landscapes for multiple ecosystem services, this study was undertaken to determine if irrigation canals function as an extension of the riparian corridor. I was specifically interested in determining if the processes within semi-arid streams that drive riparian plant community structure are manifested in earthen irrigation ditches. I examined herbaceous and woody vegetation along the middle Verde River, AZ, USA and three adjacent irrigation ditches across six months. I also collected sieved hydrochores--seeds dispersing through water--within ditches and the river twelve times. Results indicate that ditch vegetation was similar to streamside river vegetation in abundance (cover and basal area) due to surface water availability but more diverse than river streamside vegetation due to high heterogeneity. Compositionally, herbaceous vegetation along the ditch was most similar to the river banks, while low disturbance fostered woody vegetation along the ditches similar to high floodplain and river terrace vegetation. Hydrochore richness and abundance within the river was dependent on seasonality and stream discharge, but these relationships were dampened in the ditches. Species-specific strategies of hydrochory, however, did emerge in both systems. Strategies include pulse species, which disperse via hydrochory in strict accordance with their restricted dispersal windows, constant species, which are year round hydrochores, and combination species, which show characteristics of both. There was high overlap in the composition of hydrochores in the two systems, with obligate wetland species abundant in both. Upland species were more seasonally constant and abundant in the ditch water than the river. The consistency of river processes and similarity of vegetation suggest that earthen irrigation ditches do function as an extension of the riparian corridor. Thus, these man-made irrigation ditches should be considered by stakeholders for their multiple ecosystem services.
ContributorsBetsch, Jacqueline Michelle (Author) / Stromberg, Juliet C. (Thesis advisor) / Hall, Sharon J (Committee member) / Merritt, David M. (Committee member) / Arizona State University (Publisher)
Created2010
Description
This thesis explores the independent effects of the manipulation of rocks into alignments, prehistoric farming, and season on soil properties in two areas with a history of prehistoric agriculture in central Arizona, Pueblo la Plata within the Agua Fria National Monument (AFNM), and an archaeological site north of the Phoenix basin along Cave Creek (CC). Soil properties, annual herbaceous biomass and the physical properties of alignments and surface soils were measured and compared across the landscape, specifically on: 1) agricultural rock alignments that were near the archaeological site 2) geologically formed rock alignments that were located 0.5-1 km away from settlements; and 3) areas both near and far from settlements where rock alignments were absent. At AFNM, relatively well-built rock alignments have altered soil properties and processes while less-intact alignments at CC have left few legacies.
ContributorsTrujillo, Jolene Eve (Author) / Hall, Sharon J (Thesis advisor) / Collins, Scott L. (Committee member) / Spielmann, Katherine A. (Committee member) / Arizona State University (Publisher)
Created2011
Description
Throughout the Southwest, complex geology and physiography concomitant with climatic variability contribute to diverse stream hydrogeomorphologies. Many riparian plant species store their seeds in soil seed banks, and germinate in response to moisture pulses, but the climatic controls of this response are poorly understood. To better understand the ecological implications of a changing climate on riparian plant communities, I investigated seed bank responses to seasonal temperature patterns and to stream hydrogeomorphic type. I asked the following questions: Are there distinct suites of warm and cool temperature germinating species associated with Southwestern streams; how do they differ between riparian and terrestrial zones, and between ephemeral and perennial streams? How does alpha diversity of the soil seed bank differ between streams with ephemeral, intermittent, and perennial flow, and between montane and basin streams? Do streams with greater elevational change have higher riparian zone seed bank beta-diversity? Does nestedness or turnover contribute more to within stream beta-diversity?
I collected soil samples from the riparian and terrestrial zones of 21 sites, placing them in growth chambers at one of two temperature regimes, and monitoring emergence of seedlings for 12 weeks. Results showed an approximately equal number of warm and cool specialists in both riparian and terrestrials zones; generalists also were abundant, particularly in the riparian zone. The number of temperature specialists and generalists in the riparian zones did not differ significantly between perennial headwater and ephemeral stream types. In montane streams, alpha diversity of the soil seed bank was highest for ephemeral reaches; in basin streams the intermittent and perennial reaches had higher diversity. Spatial turnover was primarily responsible for within stream beta-diversity—reaches had different species assemblages. The large portion of temperature specialists found in riparian seed banks indicates that even with available moisture riparian zone plant community composition will likely be impacted by changing temperatures. However, the presence of so many temperature generalists in the riparian zones suggests that some component of the seed bank is adapted to variable conditions and might offer resilience in a changing climate. Study results confirm the importance of conserving multiple hydrogeomorphic reach types because they support unique species assemblages.
I collected soil samples from the riparian and terrestrial zones of 21 sites, placing them in growth chambers at one of two temperature regimes, and monitoring emergence of seedlings for 12 weeks. Results showed an approximately equal number of warm and cool specialists in both riparian and terrestrials zones; generalists also were abundant, particularly in the riparian zone. The number of temperature specialists and generalists in the riparian zones did not differ significantly between perennial headwater and ephemeral stream types. In montane streams, alpha diversity of the soil seed bank was highest for ephemeral reaches; in basin streams the intermittent and perennial reaches had higher diversity. Spatial turnover was primarily responsible for within stream beta-diversity—reaches had different species assemblages. The large portion of temperature specialists found in riparian seed banks indicates that even with available moisture riparian zone plant community composition will likely be impacted by changing temperatures. However, the presence of so many temperature generalists in the riparian zones suggests that some component of the seed bank is adapted to variable conditions and might offer resilience in a changing climate. Study results confirm the importance of conserving multiple hydrogeomorphic reach types because they support unique species assemblages.
ContributorsSetaro, Danika (Author) / Stromberg, Juliet (Thesis advisor) / Franklin, Janet (Committee member) / Makings, Elizabeth (Committee member) / Arizona State University (Publisher)
Created2016