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- All Subjects: Sustainability
Description
Aboveground net primary production (ANPP) is an important ecosystem process that, in drylands, is most frequently limited by water availability. Water availability for plants is in part controlled by the water holding capacity of soils. Available water holding capacity (AWHC) of soils is strongly influenced by soil texture and depth. This study drew upon localized rain gauge data and four data-sets of cover-line and biomass data to estimate ANPP and to determine annual precipitation (PPT). I measured soil depth to caliche and texture by layer of 112 plots across the four landscape units for which estimation of ANPP were available. A pedotransfer function was used to estimate AWHC from soil depth increments to depth of caliche measurements and texture analysis. These data were analyzed using simple and multivariate regression to test the effect of annual precipitation and available water holding capacity on aboveground net primary production. Soil texture remained constant among all plots (sandy loam) and depth to caliche varied from 15.16 cm to 189 cm. AWHC and the interaction term (PPT*AWHC) were insignificant (p=0.142, p=0.838) and annual PPT accounted for 18.4% of the variation in ANPP. The y-intercept was significantly different for ANPP ~ annual PPT when considering AWHC values either above or below 3 cm. Shrub ANPP was insensitive to precipitation regardless of AWHC (R2=-0.012, R2=0.014). Results from this study indicate that a model incorporating annual PPT and AWHC may not serve as a good predictor for ANPP at a site level where there is little variation in soil texture.
ContributorsWagner, Svenja K (Author) / Sala, Osvaldo E. (Thesis advisor) / Cease, Arianne (Committee member) / Hall, Sharon (Committee member) / Peters, Debra (Committee member) / Arizona State University (Publisher)
Created2019
Description
Aquatic macroinvertebrates can be key contributors to nitrogen (N) and phosphorus (P) cycling in streams. Though they exhibit intense control via trophic interactions and nutrient conversion, they may be influenced by other environmental factors that can determine total excretion-derived N, P, and N:P. Garden Canyon and Ramsey Canyon, two streams in the Huachuca Mountain Range in Southern Arizona, USA, host similar insect communities, but only Garden Canyon experiences a seasonal P limitation due to the co-precipitation of phosphate with calcium carbonate (CaCO3) in its benthic substrate (Corman et al. 2015). I performed an analysis of excretion rates of aquatic insects living in these streams to test if the P limitation is reflected in rates that insects recycle nutrients. A lower mean N:P of all insect excretion rates in Garden provides evidence for an ecosystem-scale effect, though the differences in N:P of excretion rates by individual taxa between streams did not support the hypothesis. Attributing excretion rates to actual insect densities in three years reveals that natural-occurring fluctuations in excretion rates can operate on the same magnitude as fluctuations in abundances and causes steep differences in nutrient conversion between streams. Lastly, I found that since these streams support immense insect diversity, they receive excretion-derived N and P from taxa in many different functional feeding groups, which illustrates ecosystem resilience and uniqueness.
ContributorsSanders, Ashley Marie (Author) / Sabo, John (Thesis director) / Cease, Arianne (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Locusts are a major crop pest in many parts of the world and different species are endemic to different countries. In Latin America, the South American Locust (Schistocerca cancellata) is the predominant species found mostly in Argentina, Chile, Bolivia, Paraguay, and southern Brazil with Argentina being the most affected. Several control and management practices, including biological control, have been implemented in these countries in the past to control the locusts and reduce their impact on crop and vegetation, however, effective long-term control and management practices will require a detail understanding of how the predominant locust species in this region responds to resource variation. Research has shown that there is strong evidence that locusts, and many other organisms, will actively balance dietary macronutrients (protein, carbohydrates, and lipids) to optimize growth, survival, and/or reproduction. A study by Cease et. al, 2017, on the dietary preferences of the Mongolian locust (Oedaleus asiaticus) showed that it prefers diets that are high in carbohydrates over diets that are high in protein, in this case locusts self-selected a 1:2 ratio of protein:carbohydrate. This and many other studies provide vital insight into the nutritional and feeding preferences of these locust species but the effects that this difference in protein: carbohydrate preferences has on growth, egg production, flight potential, and survival has yet to be fully explored, hence, this study investigates the effects that nitrogen fertilization of wheatgrass will have on the growth, egg production, survival, and flight muscle mass of the South American locust in a controlled, laboratory environment.
ContributorsManneh, Balanding (Author) / Cease, Arianne (Thesis director) / Overson, Rick (Committee member) / School of Sustainability (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
In the face of the world's most pressing sustainability challenges, such as climate change, ecosystem degradation, and loss of biodiversity, the following questions must be explored: Why are these situation occurring? How can we understand their complexity? How can we research these challenges to mitigate negative outcomes? This thesis investigates the relationships between people and nature through coupled human and natural systems, or CHANS, and argues for a transdisciplinary research approach for sustainability science. The following questions and topics are discussed: 1. The Complexity of Sustainability and Implications for Traditional Research Approaches 2. Coupled Human and Natural Systems Research 3. What is Transdisciplinary Research, and How Does it Relate to the Living With Locusts Team's Coupled Human and Natural Systems Research? This thesis uses the case of a team researching international locust plagues to argue for this approach. The team's project is titled "Living With Locusts" and is directed by Arianne Cease of Arizona State University's School of Sustainability.
ContributorsLantz, Kayna Mishelle (Author) / Cease, Arianne (Thesis director) / Campbell, Jacob (Committee member) / School of Sustainability (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12