Animal psychology is the study of how animals interact with one another, their environment, and with humans. This can be done in two different settings, the wild and captivity, and through two different approaches, academic research and practice. Academic research relies primarily on behavioral observation for data collection. Practice uses behavioral observation as well, but allows for a more hands on experience and lets the practitioner make improvements in the quality of life. I interviewed two people, one who practices in captivity, and one who does research in the wild. Dr. David Bunn has done research on wild animals in Kruger National Park in South Africa for over twenty years, studying human-animal interactions. Hilda Tresz has worked in zoos nearly forty years and specializes in chimps. Working within the same field, but utilizing a different setting and approach makes a big difference in the feel of the job. Though I found many differences between the two by doing my own research and from conducting interviews, there are many similarities to note as well. The general field of animal psychology is very rewarding, requires a lot of patience, and leads to a better understanding of animal behavior and how to care for specific species of animals. Working with captive animals allows for the opportunity to make a big difference in animal's lives through behavioral enrichment and general care. Working in the wild allows us to understand the innate animal behaviors displayed. Through practice, people get more hands on experience; while through research, you get to observe animals in their native habitats. Each setting and approach has it's own benefits depending on what each person's goals are for their job.

In Senegal, West Africa, soils are a vital resource for livelihoods and food security in smallholder farming communities. Low nitrogen (N) soils pose obvious challenges for crop production but may also, counterintuitively, promote the abundance of agricultural pests like the Senegalese locust, Oedaleus senegalensis. In this study I investigated how the abundance of locusts and grasshoppers are impacted by soil fertility through plant nutrients and how these variables change across land use types. We worked in two rural farming villages in the Kaffrine region of Senegal. Overall, there was little variation in soil properties and an agricultural landscape low in soil organic matter (SOM) and inorganic soil nitrogen. I corroborated that SOM is a significant driver of soil inorganic N, which had a positive relationship to plant N content. Of the management practices we surveyed, fallowing fields was important for soil nutrient restoration and years spent fallow was significantly correlated to inorganic soil N and SOM. O. senegalensis was least abundant in groundnut areas where plant N was highest. Additionally, I found a significant negative correlation between O. senegalensis abundance and plant N, suggesting that plant nutrients are an important driver of their populations. Grasshoppers, excluding O. senegalensis, were more numerous in grazing areas and fallow areas, perhaps due to a higher diversity of ecological niches and host plants. These results connect land use, soil, and vegetation to herbivores and suggest that improving soil fertility could be used as an alternative to pesticides to keep locusts at bay and improve crop yields.

The Prosopis genus of trees, also known as mesquites, are uniquely equipped to allow for an agroforestry regime in which crops can be grown beneath the canopy of the tree. Mesquites have the ability to redistribute water moisture in such a way that allows plants under the canopy to use water that has been brought up by the roots of mesquite trees. This means that there is a potential for food crops to be grown under the trees without using additional irrigation measures. This could be used where access to water is limited or for a sustainability-minded farmer who is trying to reduce water inputs in an arid environment. Mesquite trees produce a variety of products, including lumber and bean pods that can be ground down into an edible flour. Both products demand a high price in the marketplace and are produced in addition to the crops that can potentially be grown beneath the mesquite tree. In order to determine whether or not it is possible to grow crops under mesquite trees, I reviewed a wide range of literature regarding hydraulic redistribution, mesquite trees in general, and what plants might be best suited for growing beneath a mesquite. The list of plants was narrowed down to four crops that seemed most likely to survive in shaded, low water conditions in a hot environment. There has not been any research done on crops growing beneath mesquite trees, so the next step for research would be to experiment with each of the crops to determine how well each species can adapt to the specified conditions.

The mainstream American environmental movement has a reputation for being ethnically homogenous (i.e., white), especially within the field of conservation. Low minority involvement has been noted and discussed in the conservation literature and within environmental organizations, but these discussions aren't always informed by the explicit social justice concerns critical to understanding the complex intersection of environmental and social issues. Communities of color have expressed concern for environmental and conservation issues, but often frame those issues in a different way than is common in mainstream conservation science, a framing that we can appreciate through a deeper analysis of the values and goals of the environmental justice (EJ) movement. A more thorough inclusion of EJ principles could be an effective method to increase ethnic diversity in the field of conservation, particularly within higher education conservation programs like the Conservation Biology and Ecology (CBE) concentration at Arizona State University. This thesis frames the broader challenge of diversity in conservation, the history and current state of the conservation movement, and the history of the environmental justice movement via a literature review. I then evaluate the university's CBE program on the basis of its diversity through an analysis of demographic data on undergraduate ethnicity from the School of Life Sciences. I conclude with a series of recommendations for enhancing the diversity of ASU's CBE program moving forward.

“Extremophile” is used to describe life that has adapted to extreme conditions and the conditions they live in are often used to understand the limits of life. In locations with low precipitation and high solar radiation, photosynthetic cyanobacteria can colonize the underside of quartz fragments, forming ‘hypoliths.’ The quartz provides protection against wind, reduces solar radiation, and slows the rate of evaporation following infrequent rain or fog events. In most desert systems, vascular plants are the main primary producers. However, hypoliths might play a key role in carbon fixation in hyperarid deserts that are mostly devoid of vegetation. I investigated hypolith distribution and carbon fixation at six sites along a rainfall and fog gradient in the central Namib Desert in Namibia. I used line point intersect transects to assess ground cover (bare soil, colonized quartz fragment, non-colonized quartz fragment, non-quartz rock, grass, or lichen) at each site. Additionally, at each site I selected 12 hypoliths and measured cyanobacteria colonization on quartz and measured CO2 flux of hypoliths at five of the six sites.
Ground cover was fairly similar among sites, with bare ground > non-colonized quartz fragments > colonized quartz fragments > non-quartz rocks. Grass was present only at the site with the highest mean annual precipitation (MAP) where it accounted for 1% of ground cover. Lichens were present only at the lowest MAP site, where they accounted for 30% of ground cover. The proportion of quartz fragments colonized generally increased with MAP, from 5.9% of soil covered by colonized hypoliths at the most costal (lowest MAP) site, to 18.7% at the most inland (highest MAP) site. There was CO2 uptake from most hypoliths measured, with net carbon uptake rates ranging from 0.3 to 6.4 μmol m-2 s-1 on well hydrated hypoliths. These carbon flux values are similar to previous work in the Mojave Desert. Our results suggest that hypoliths might play a key role in the fixation of organic carbon in hyperarid ecosystems where quartz fragments are abundant, with MAP constraining hypolith abundance. A better understanding of these extremophiles and the niche they fill could give an understanding of how microbial life might exist in extraterrestrial environments similar to hyperarid deserts.

The nutrient dynamics of degradation have been studied almost exclusively in mesic (not arid or semi-arid) ecosystems. In arid ecosystems, we do know that photodegradation can cause significant mass loss and that lignin plays a dual role in the processes of degradation: it slows biodegradation due to its rigid chemical structure but can speed up photodegradation via the carbon mineralization process. This experiment attempts to assess the nutrient dynamics of nitrogen (N) and phosphorus (P) that occur while overall mass is being lost via photodegradation. We took Ambrosia deltoidea litter from 5 sites within the Phoenix city core and 5 sites downwind of the city of Phoenix. Half of this litter was N and P enriched from a previous experiment and half was control. We split the litter into UV opaque and UV transparent litter bags that had holes punched in them to allow microbial interaction. These bags were picked up at sampling periods of 10, 20, 30, and 40 weeks. All samples were then tested for mass loss, lignin content, carbon (C) content, N content, and P content. We found that downwind samples lost more mass than the core. There was little effect over time on N content and little disparity in P trends between the samples. P behaved as expected with an initial rise due to microbial interaction and then a decline as the microbes released P. Lignin concentration rose in a similar fashion at both core and downwind sites confirming that lignin remains in litter through the process of photodegradation. One interesting result was an logarithmic-like decrease in C:N ratio and C:P ratio for the downwind samples but a fairly constant ratio in the core samples. It is clear that these decreasing ratios result not from increased N or P, but instead from rapidly decreasing C. Overall, we conclude that neither N nor P is affected significantly by photodegradation at either site. N deposition appears to slow mass loss, but speed up N release, at least in the early stages of decomposition.

In this project, I investigated the ecosystem services, or lack thereof, that landscape designs created in terms of microclimate modification at 11 residential homes throughout the Phoenix Metro Area. I also created an article for the homeowners who participated, explaining what I did and how they could apply my research. My research question was how a person can achieve a comfortable outdoor climate in their yard without over-using scarce water resources. I hypothesized that there would be a negative correlation between the maximum air temperature and the percent shade in each yard, regardless of the percent grass. I analyzed the data I collected using the program, R, and discovered that my hypothesis was supported for the month of July. These results are in line with previous studies on the subject and can help homeowners make informed decisions about the effects their landscaping choices might have.

Microarthropods play important roles in the decomposition process of the detrital food web, where they break down organic matter and return nutrients to the soil. However, only a small percentage of the belowground microarthropod population has been studied or even discovered, leading to a decrease in the knowledge of all of the processes carried out by these organisms and their importance to the soil. This is because microarthropod extraction methods are not 100% effective at collecting specimens. This study aimed to find an ideal quantitative procedure to better record the number of microarthropods existing in the soil and to determine if a seasonal variation exists that effects the success of extraction. Two extraction methods, including dynamic extraction and heptane flotation extraction, were compared across two seasons, a dry season (June) and a wet season (September). Average biomasses and average richness were calculated for four different functional groups, including Prostigmata, Mesostigmata, Cryptostigmata, and Collembola, across the two seasons, and statistical analysis was performed to determine if any differences that existed were statistically significant. Results indicate that the dynamic extraction method was significantly more effective for the collection of microarthropods during the wet season, and the heptane extraction method was significantly more effective during the dry season. In addition, the heptane procedure recovered samples of higher average richness than the dynamic method during both seasons. The heptane procedure works best for extraction during the dry season because it is able to collect organisms that entered into an ametabolic anhydrobiotic state to escape desiccation. These organisms form a protective lipid layer around their exoskeletons to retain water, and the non-polar exoskeletons display a chemical affinity to the heptane fluid, allowing for collection out of the soil and into the heptane layer. Despite these results, no one method is entirely superior to the other, and the most efficacious procedure depends on the researcher's aim of study.

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.