Matching Items (23)
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- All Subjects: Ecology
- Creators: School of Life Sciences
- Status: Published
Description
This paper explores the relationship between wildfire management and the consideration of ecological and environmental concerns in Arizona. To get a proper perspective on the current state of wildfire management in Arizona, information on two wildfire management programs, the Four Forests Restoration Initiative and FireScape, was researched and analyzed, as well as contemporary fire policy, a history of wildfire in Arizona, and two recent fires in Sedona, AZ. The two fires in Sedona, the Brins Fire of 2006 and the Slide Fire of 2014, act as a focal point for this ecological management transition, as even within an 8-year period, we can see the different ways the two fires were managed and the transition to a greater ecological importance in management strategies. These all came together to give a full spectrum for the factors that have led to more ecologically-prominent wildfire management strategies in Arizona.
ContributorsGeorge-Sills, Dylan (Author) / Pyne, Stephen (Thesis director) / Hirt, Paul (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Sustainability (Contributor)
Created2015-05
Description
Water is the main driver of net primary productivity (NPP) in arid ecosystems, followed by nitrogen and phosphorous. Precipitation is the primary factor in determining water availability to plants, but other factors such as surface rocks could also have an impact. Surface rocks may positively affect water availability by preventing evaporation from soil, but at higher densities, surface rocks may also have a negative impact on water availability by limiting water infiltration or light availability. However, the direct relationship between rock cover and aboveground net primary productivity (ANPP), a proxy for NPP, is not well understood. In this research we explore the relationship between rock cover, ANPP, and soil nutrient availability. We conducted a rock cover survey on long-term fertilized plots at fifteen sites in the Sonoran Desert and used 4 years of data from annual plant biomass surveys to determine the relationship between peak plant biomass and surface rock cover. We performed factorial ANCOVA to assess the relationship among annual plant biomass, surface rocks, precipitation, and fertilization treatment. Overall we found that precipitation, nutrients, and rock cover influence growth of Sonoran Desert annual plants. Rock cover had an overall negative relationship with annual plant biomass, but did not show a consistent pattern of significance over four years of study and with varying average winter precipitation.
ContributorsShaw, Julea Anne (Author) / Hall, Sharon (Thesis director) / Sala, Osvaldo (Committee member) / Cook, Elizabeth (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
In today's world, critical thinking and using a systems approach to problem solving are skills that are far too rare. In the age of information, the truth has become muddled by "fake news" and a constant barrage of exaggerations or blatant falsehoods. Without critical thinking skills, "many members of our society do not command the scientific literacy necessary to address important societal issues and concerns" (NCES 2012, p.11). Additionally, far too many people are incapable of thinking long term and understanding how their actions affect others. Because of this shortsightedness our world is facing one of its biggest ecological crises \u2014 global warming confounded by overpopulation and overconsumption. Now, more than ever, it is critical "for our young people to have a basic understanding of the relevant scientific ideas, technologies and ethical issues and powers of reasoning, to be prepared to face these issues" (Harlen et al., 2015). I believe that investigating innovative ways to teach ecology could be an important step to accomplishing this. Learning to think like a scientist forces people to rely on facts, follow similar protocols to deduce these facts, and be able to think critically about misleading events. More specifically, ecology education will allow people to develop those skills while also learning about team work, open-mindedness, and their environment. Ecology is defined as "the branch of biology that deals with the relations of organisms to one another and to their physical surroundings" (Dictionary.com, 2018). It is clear that this subcategory of science could act as a powerful introduction to the scientific world and how we relate to it. Its introduction at a young age has the potential to create a generation of conscientious and curious lifelong learners. In an attempt to support effective ways to teach ecology, I developed an educational unit and applied it in different educational contexts. My target audience was elementary aged students and I tested this unit with children in Phoenix Metropolitan Area afterschool programs. I taught core concepts of ecology \u2014 the water cycle, the sun's energy, plants and photosynthesis, and food webs \u2014in a sequence of lesson plans that build upon each other. Finally, I determined the appropriate age group and setting for these lesson plans through research and in-class observations. In this document, I explain the process I went through in developing my lesson plans, why I felt compelled to make them, and my experiences in implementing them.
ContributorsVotaw, Alexandra Lindsay (Author) / Larson, Kelli (Thesis director) / Herrmann, Lisa (Committee member) / York, Abigail (Committee member) / School of Art (Contributor) / The Design School (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Peatlands are a type of wetlands where the rate of accumulation of organic matter exceed the rate of decomposition and have accumulated more than 30 cm of peat (Joosten and Clark, 2002). Peatlands store approximately 30% of all terrestrial carbon as recalcitrant peat, partially decomposed plant and microbial biomass, while simultaneously producing almost 40% of the globally emitted methane (Schmidt et al., 2016), making peatlands an important component of the carbon budgets. Published research indicates that the efficiency of carbon usage among microbial communities can determine the soil-carbon response to rising temperatures (Allison et al. 2010). By determining carbon consumption in peatland soils, total community respiration response, and community structure change with additions, models of carbon use efficiency in permafrost peatlands will be well-informed and have a better understanding of how the peatlands will respond to, and utilize, increased availability of carbon compounds due to the melting permafrost. To do this, we will sequence Lutose deep core samples to observe baseline microbial community structure at different depths and different age-gradients, construct substrate incubations of glucose and propionate and observe community respiration response via a gas chromatography flame ionization detector, track the glucose and propionate additions with high-performance liquid chromatography (HPLC), and sequence the samples once more to determine if there was a deviation from the initial community structure obtained prior to the incubations. We found that our initial sequencing data was supported by previous work (Lin et al., 2014), however we were unable to sequence samples post-incubation due to time constraints. In this sequencing analysis we found that the strongest variable that made samples biologically similar was the age-gradient site in which they were extracted. We found that the group with glucose additions produced the most carbon dioxide compared with the other treatments, but was not the treatment that dominated the production of methane. Finally, in the HPLC samples that were analyzed, we found that glucose is likely forming the most by-product accumulation from mass balance calculations, while propionate is likely forming the least. Future experimentation should focus on the shortcomings of this experiment. Further analysis of 16S rRNA sequencing data from after the incubations should be analyzed to determine the change in microbial community structure throughout the experiment. Furthermore, HPLC analysis for the several samples need to be done and followed up with mass balance to determine where the added glucose and propionate are being allocated within the soil. Once these pieces of the puzzle are put into place, our original question of how the microbial community structure changes at different depths and age-gradients within permafrost peatlands will be conclusively answered.
ContributorsFrese, Alexander Nicholas (Author) / Cadillo-Quiroz, Hinsby (Thesis director) / van Paassen, Leon (Committee member) / Sarno, Analissa (Committee member) / School of Life Sciences (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Ephemeral and intermittent streams are valuable sources of surface water support in the arid ecosystems of the Southwestern United States. These streams account for over 80% of the streams in the American Southwest and their importance has been indicated in many studies. Ephemeral and intermittent streams support a wide range of plant and animal species in both continuous and episodic fashions. This study aimed to gain a better understanding of the relationship between streamflow permanence and patterns of biomass and secondary production of the riparian fauna these ecosystems support. This was accomplished through a yearlong survey in the Huachuca Mountains of Southeastern, Arizona where macroinvertebrates were collected at various sites along a gradient of streamflow permanence before, during, and after the three month monsoon season that supplies most of the annual rainfall in this region. The results of my surveys indicate that 1) Sites characterized by low streamflow permanence were more responsive to changes in precipitation than sites characterized by relatively high streamflow permanence 2) In ephemeral streams, there is a significant peak in terrestrial macroinvertebrate production and biomass both during and after the monsoon season 3) streamflow permanence may convey consistent but not exceptional secondary production whereas seasonality in rainfall may convey exceptional but episodic secondary production—more so in sites where streamflow is not consistent.
ContributorsMcCartin, Michael Patrick (Author) / Sabo, John (Thesis director) / Stromberg, Juliet (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
Fifty years ago, we embarked on a journey for the first time in all of history \u2014 an exploration of the final frontier: outer space. Now, having been to the moon and back, we are still exploring the unknown. In the 21st century, we have pioneered genetic cloning and made other unprecedented biotechnological advances. Similarly, artists have ventured into their own frontier, branching out of their own narrowly defined areas and breaking down barriers \u2014 barriers between art and science, between the concert hall and the outdoors, between manmade instruments and the sounds of nature. At first glance, it seems that music and science have little in common. But upon closer inspection, one will discover that there are similarities and intersections between these two fields that deserve attention. Interest in the correlation between music and science can be traced back at least as far as Ancient Greece; since Pythagoras, mathematicians, physicists, acousticians and many others have addressed connections between the two fields in manifold ways. It is becoming increasingly obvious that art and science are not at the opposite ends of the spectrum, where conventional wisdom has traditionally located them, but at the opposite sides of the same coin. In my thesis, I seek to explore the connections between music and the sciences by examining the field of acoustic ecology. I will first provide an overview of music as an interdisciplinary field. Then I will undertake two case studies of musicians whose endeavors have been significant to the field of acoustic ecology, and consider the benefits that can be drawn from their work. These artists are David Dunn and Andrea Polli. I will draw on their philosophy, writings and art as well as on secondary literature. I will take a philosophical approach to the intersections between the two areas and identify heretofore little explored aspects of the interdisciplinary potential of these two fields.
ContributorsChou, Cecilia (Author) / Feisst, Sabine (Thesis director) / Hackbarth, Glenn (Committee member) / Barrett, The Honors College (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Music (Contributor)
Created2014-05
Description
It is well known that deficiencies in key chemical elements (such as phosphorus, P) can reduce animal growth; however, recent empirical data have shown that high levels of dietary nutrients can also reduce animal growth. In ecological stoichiometry, this phenomenon is known as the "stoichiometric knife edge," but its underlying mechanisms are not well-known. Previous work has suggested that the crustacean zooplankter Daphnia reduces its feeding rates on phosphorus-rich food, causing low growth due to insufficient C (energy) intake. To test for this mechanism, feeding rates of Daphnia magna on algae (Scenedesmus acutus) differing in C:P ratio (P content) were determined. Overall, there was a significant difference among all treatments for feeding rate (p < 0.05) with generally higher feeding rates on P-rich algae. These data indicate that both high and low food C:P ratio do affect Daphnia feeding rate but are in contradiction with previous work that showed that P-rich food led to strong reductions in feeding rate. Additional experiments are needed to gain further insights.
ContributorsSchimpp, Sarah Ann (Author) / Elser, James (Thesis director) / Neuer, Susanne (Committee member) / Peace, Angela (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Sustainability (Contributor)
Created2014-05
Description
Chronic stress often leads to cognitive deficits, especially within the spatial memory domain mediated by the hippocampus. When chronic stress ends and a no-stress period ensues (i.e., washout, WO), spatial ability improves, which can be better than non-stressed controls (CON). The WO period is often the same duration as the chronic stress paradigm. Given the potential benefit of a post-stress WO period on cognition, it is important to investigate whether this potential benefit of a post-stress WO period has long-lasting effects. In this project, chronic restraint (6hr/d/21d) in Sprague-Dawley rats was used, as it is the minimum duration necessary to observe spatial memory deficits. Two durations of post-stress WO were used following the end of chronic restraint, 3 weeks (STR-WO3) and 6 weeks (STR-WO6). Immediately after chronic stress (STR-IMM) or the WO periods, rats were tested on various cognitive tests. We corroborated past studies that chronic stress impaired spatial memory (STR-IMM vs CON). Interestingly, STR-WO3 and STR-WO6 failed to demonstrate improved spatial memory on a radial arm water maze task, performing similarly as STR-IMM. Performance outcomes were unlikely from differences in anxiety or motivation because rats from all conditions performed similarly on an open field task and on a simple object recognition paradigm, respectively. However, performance on object placement was unusual in that very few rats explored, suggesting some degree of anxiety or fear in all groups. One possible interpretation of the unusual results of the 3 week washout group may be attributed to the different spatial memory tasks used across studies or external factors from the study. Further exploration of these other factors led to the conclusion that they did not play a role and the STR-WO3 RAWM data were anomalous to other studies. This suggests that a washout period following chronic stress may not be fully understood.
ContributorsFlegenheimer, Aaron Embden (Author) / Conrad, Cheryl (Thesis director) / Bimonte-Nelson, Heather (Committee member) / Ortiz, J. Bryce (Committee member) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Little is known about the diversity and role of bacteriophages in carbon (C) rich ecosystems such as peatlands in tropical and temperate regions. In fact, there is no currently published assessment of phage abundance on diversity in a key tropical ecosystem such as Amazon peatlands. To better understand phage assemblages in terrestrial ecosystems and how bacteriophages influence organic C cycling to final products like CO2 and CH4, phage communities and phage-like particles were recovered, quantified, and viable phage particles were enriched from pore water from contrasting Amazon peatlands. Here we present the first results on assessing Amazon bacteriophages on native heterotrophic bacteria. Several steps to test for methodological suitability were taken. First, the efficiency of iron flocculation method was determined using fluorescent microscopy counts of phage TLS, a TolC-specific and LPS-specific bacteriophage, and Escherichia coli host pre- and post-extraction method. One-hundred percent efficiency and 0.15% infectivity was evidenced. Infectivity effects were determined by calculating plaque forming units pre and post extraction method. After testing these methods, fieldwork in the Amazon peatlands ensued, where phages were enriched from pore water samples. Phages were extracted and concentrated by in tandem filtering rounds to remove organic matter and bacteria, and then iron flocculation to bind the phages and allow for precipitation onto a filter. Phage concentrates were then used for overall counts, with fluorescent microscopy, as well as phage isolation attempts. Phage isolations were performed by first testing for lysis of host cells in liquid media using OD600 absorbance of cultures with and without phage concentrate as well as attempts with the cross-streaking methods. Forty-five heterotrophic bacterial isolates obtained from the same Amazon peatland were challenged with phage concentrates. Once a putative host was found, steps were taken to further propagate and isolate the phage. Several putative phages were enriched from Amazon peatland pore water and require further characterization. TEM imaging was taken of two phages isolated from two plaques. Genomes of selected phages will be sequenced for identification. These results provide the groundwork for further characterizing the role bacteriophage play in C cycling and greenhouse gas production from Amazon peatland soils.
ContributorsSpring, Jessica Lynette (Author) / Cadillo-Quiroz, Hinsby (Thesis director) / Haydel, Shelley (Committee member) / Misra, Rajeev (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The bull shark, Carcharhinus leucas, is a large species that it is commonly distributed worldwide in tropical and subtropical waters. Despite the bull sharks global distribution, little is known about its life history. In particular, the limited reproductive information suggests the bull shark is placental viviparous, assumed to have a biennial cycle, and that newborn pup nurseries are near the coast. In order to conserve and protect any species, an understanding of the habitats where reproductive events occur is needed. In order to better understand the habitat use in Biscayne bay, Fla, and whether certain areas are critical during the reproductive cycle of bull sharks, I will evaluate circulating levels of the hormones progesterone, estradiol, and testosterone using radioimmunoassay. These samples were collected by the University of Miami opportunistically between 2012-2020 shipped to Arizona State University, where they were analyzed. For my study a total of 73 mature samples, 27 females and 46 males, were collected over the sampling period. The results indicated that Biscayne bay is an important gestation area for bull sharks. The hormonal trends for males and females demonstrated an interesting reproductive cycle, which were further supported through other placental viviparous reproductive patterns. Females had a low level of estradiol throughout most of the year, besides in the summer where there were no sharks in the bay due to movement to estuaries. During their return to the bay, there was a peak in progesterone indicating early pregnancy. Male testosterone levels indicated that there was a production in sperm right before females speculated peak in estradiol.
ContributorsJara-Aguirre, Nisi G (Author) / Sulikowski, James (Thesis director) / Ferry, Lara (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05