Matching Items (12)
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- All Subjects: Wildlife conservation
- All Subjects: Reptiles
- Creators: Bateman, Heather L
- Creators: DeNardo, Dale
- Status: Published
Description
In riparian ecosystems, reptiles and amphibians are good indicators of environmental conditions. Herpetofauna have been linked to specific microhabitat characteristics, microclimates, and water resources in riparian forests. My objective was to relate herpetofauna abundance to changes in riparian habitat along the Virgin River caused by the Tamarix biological control agent, Diorhabda carinulata, and riparian restoration.
During 2013 and 2014, vegetation and herpetofauna were monitored at 21 riparian locations along the Virgin River via trapping and visual encounter surveys. Study sites were divided into four stand types based on density and percent cover of dominant trees (Tamarix, Prosopis, Populus, and Salix) and presence of restoration activities: Tam, Tam-Pros, Tam-Pop/Sal, and Restored Tam-Pop/Sal. Restoration activities consisted of mechanical removal of non-native trees, transplanting native trees, and introduction of water flow. All sites were affected by biological control. I predicted that herpetofauna abundance would vary between stand types and that herpetofauna abundance would be greatest in Restored Tam-Pop/Sal sites due to increased habitat openness and variation following restoration efforts.
Results from trapping indicated that Restored Tam-Pop/Sal sites had three times more total lizard and eight times more Sceloporus uniformis captures than other stand types. Anaxyrus woodhousii abundance was greatest in Tam-Pop/Sal and Restored Tam-Pop/Sal sites. Visual encounter surveys indicated that herpetofauna abundance was greatest in the Restored Tam-Pop/Sal site compared to the adjacent Unrestored Tam-Pop/Sal site. Habitat variables were reduced to six components using a principle component analysis and significant differences were detected among stand types. Restored Tam-Pop/Sal sites were most similar to Tam-Pop/Sal sites. S. uniformis were positively associated with large woody debris and high densities of Populus, Salix, and large diameter Prosopis.
Restored Tam-Pop/Sal sites likely supported higher abundances of herpetofauna, as these areas exhibited greater habitat heterogeneity. Restoration activities created a mosaic habitat by reducing canopy cover and increasing native tree density and surface water. Natural resource managers should consider implementing additional restoration efforts following biological control when attempting to restore riparian areas dominated by Tamarix and other non-native trees.
During 2013 and 2014, vegetation and herpetofauna were monitored at 21 riparian locations along the Virgin River via trapping and visual encounter surveys. Study sites were divided into four stand types based on density and percent cover of dominant trees (Tamarix, Prosopis, Populus, and Salix) and presence of restoration activities: Tam, Tam-Pros, Tam-Pop/Sal, and Restored Tam-Pop/Sal. Restoration activities consisted of mechanical removal of non-native trees, transplanting native trees, and introduction of water flow. All sites were affected by biological control. I predicted that herpetofauna abundance would vary between stand types and that herpetofauna abundance would be greatest in Restored Tam-Pop/Sal sites due to increased habitat openness and variation following restoration efforts.
Results from trapping indicated that Restored Tam-Pop/Sal sites had three times more total lizard and eight times more Sceloporus uniformis captures than other stand types. Anaxyrus woodhousii abundance was greatest in Tam-Pop/Sal and Restored Tam-Pop/Sal sites. Visual encounter surveys indicated that herpetofauna abundance was greatest in the Restored Tam-Pop/Sal site compared to the adjacent Unrestored Tam-Pop/Sal site. Habitat variables were reduced to six components using a principle component analysis and significant differences were detected among stand types. Restored Tam-Pop/Sal sites were most similar to Tam-Pop/Sal sites. S. uniformis were positively associated with large woody debris and high densities of Populus, Salix, and large diameter Prosopis.
Restored Tam-Pop/Sal sites likely supported higher abundances of herpetofauna, as these areas exhibited greater habitat heterogeneity. Restoration activities created a mosaic habitat by reducing canopy cover and increasing native tree density and surface water. Natural resource managers should consider implementing additional restoration efforts following biological control when attempting to restore riparian areas dominated by Tamarix and other non-native trees.
ContributorsMosher, Kent (Author) / Bateman, Heather L (Thesis advisor) / Stromberg, Juliet C. (Committee member) / Miller, William H. (Committee member) / Arizona State University (Publisher)
Created2014
Description
Worldwide, riverine floodplains are among the most endangered landscapes. In response to anthropogenic impacts, riverine restoration projects are considerably increasing. However, there is a paucity of information on how riparian rehabilitation activities impact non-avian wildlife communities. I evaluated herpetofauna abundance, species richness, diversity (i.e., Shannon and Simpson indices), species-specific responses, and riparian microhabitat characteristics along three reaches (i.e., wildland, urban rehabilitated, and urban disturbed) of the Salt River, Arizona. The surrounding uplands of the two urbanized reaches were dominated by the built environment (i.e., Phoenix metropolitan area). I predicted that greater diversity of microhabitat and lower urbanization would promote herpetofauna abundance, richness, and diversity. In 2010, at each reach, I performed herpetofauna visual surveys five times along eight transects (n=24) spanning the riparian zone. I quantified twenty one microhabitat characteristics such as ground substrate, vegetative cover, woody debris, tree stem density, and plant species richness along each transect. Herpetofauna species richness was the greatest along the wildland reach, and the lowest along the urban disturbed reach. The wildland reach had the greatest diversity indices, and diversity indices of the two urban reaches were similar. Abundance of herpetofauna was approximately six times lower along the urban disturbed reach compared to the two other reaches, which had similar abundances. Principal Component Analysis (PCA) reduced microhabitat variables to five factors, and significant differences among reaches were detected. Vegetation structure complexity, vegetation species richness, as well as densities of Prosopis (mesquite), Salix (willow), Populus (cottonwood), and animal burrows had a positive correlation with at least one of the three herpetofauna community parameter quantified (i.e., herpetofauna abundance, species richness, and diversity indices), and had a positive correlation with at least one herpetofauna species. Overall, rehabilitation activities positively influenced herpetofauna abundance and species richness, whereas urbanization negatively influenced herpetofauna diversity indices. Based on herpetofauna/microhabitat correlations established, I developed recommendations regarding microhabitat features that should be created in order to promote herpetofauna when rehabilitating degraded riparian systems. Recommendations are to plant vegetation of different growth habit, provide woody debris, plant Populus, Salix, and Prosopis of various ages and sizes, and to promote small mammal abundance.
ContributorsBanville, Mélanie Josianne (Author) / Bateman, Heather L (Thesis advisor) / Brady, Ward (Committee member) / Stromberg, Juliet (Committee member) / Arizona State University (Publisher)
Created2011
Description
Parental care provides many benefits to offspring. One widely realized benefit is enhanced regulation of offspring's thermal environment. The developmental thermal environment during development can be optimized behaviorally through nest site selection and brooding, and it can be further enhanced by physiological heat production. In fact, enhancement of the developmental thermal environment has been proposed as the initial driving force for the evolution of endothermy in bird and mammals. I used pythons (Squamata: Pythonidae) to expand existing knowledge of behavioral and physiological parental tactics used to regulate offspring thermal environment. I first demonstrated that brooding behavior in the Children's python (Antaresia childreni) is largely driven by internal mechanisms, similar to solitary birds, suggesting that the early evolution of the parent-offspring association was probably hormonally driven. Two species of python are known to be facultatively thermogenic (i.e., are endothermic during reproduction). I expand current knowledge of thermogenesis in Burmese pythons (Python molurus) by demonstrating that females use their own body temperature to modulate thermogenesis. Although pythons are commonly cited as thermogenic, the actual extent of thermogenesis within the family Pythonidae is unknown. Thus, I assessed the thermogenic capability of five previously unstudied species of python to aid in understanding phylogenetic, morphological, and distributional influences on thermogenesis in pythons. Results suggest that facultative thermogenesis is likely rare among pythons. To understand why it is rare, I used an artificial model to demonstrate that energetic costs to the female likely outweigh thermal benefits to the clutch in species that do not inhabit cooler latitudes or lack large energy reserves. In combination with other studies, these results show that facultative thermogenesis during brooding in pythons likely requires particular ecological and physiological factors for its evolution.
ContributorsBrashears, Jake (Author) / DeNardo, Dale (Thesis advisor) / Harrison, Jon (Committee member) / Deviche, Pierre (Committee member) / McGraw, Kevin (Committee member) / Smith, Andrew (Committee member) / Arizona State University (Publisher)
Created2012
Description
There is considerable recent interest in the dynamic nature of immune function in the context of an animal’s internal and external environment. An important focus within this field of ecoimmunology is on how availability of resources such as energy can alter immune function. Water is an additional resource that drives animal development, physiology, and behavior, yet the influence hydration has on immunity has received limited attention. In particular, hydration state may have the greatest potential to drive fluctuations in immunity and other physiological functions in species that live in water-limited environments where they may experience periods of dehydration. To shed light on the sensitivity of immune function to hydration state, I first tested the effect of hydration states (hydrated, dehydrated, and rehydrated) and digestive states on innate immunity in the Gila monster, a desert-dwelling lizard. Though dehydration is often thought to be stressful and, if experienced chronically, likely to decrease immune function, dehydration elicited an increase in immune response in this species, while digestive state had no effect. Next, I tested whether dehydration was indeed stressful, and tested a broader range of immune measures. My findings validated the enhanced innate immunity across additional measures and revealed that Gila monsters lacked a significant stress hormone response during dehydration (though results were suggestive). I next sought to test if life history (in terms of environmental stability) drives these differences in dehydration responses using a comparative approach. I compared four confamilial pairs of squamate species that varied in habitat type within each pair—four species that are adapted to xeric environments and four that are adapted to more mesic environments. No effect of life history was detected between groups, but hydration was a driver of some measures of innate immunity and of stress hormone concentrations in multiple species. Additionally, species that exhibited a stress response to dehydration did not have decreased innate immunity, suggesting these physiological responses may often be decoupled. My dissertation work provides new insight into the relationship between hydration, stress, and immunity, and it may inform future work exploring disease transmission or organismal responses to climate change.
ContributorsMoeller, Karla T (Author) / DeNardo, Dale (Thesis advisor) / Angilletta, Michael (Committee member) / French, Susannah (Committee member) / Rutowski, Ronald (Committee member) / Sabo, John (Committee member) / Arizona State University (Publisher)
Created2016
Description
Species conservation requires an understanding of the habitats on which that species depends as well as how it moves within and among those habitats. Knowledge of these spatial and temporal patterns is vital for effective management and research study design. Bubbling Ponds Hatchery in Cornville, Arizona, supports a robust population of the northern Mexican gartersnake (Thamnophis eques megalops), which was listed as threatened under the Endangered Species Act in 2014. Natural resource managers are interested in understanding the ecology of gartersnakes at this site to guide hatchery operations and to serve as a model for habitat creation and restoration. My objectives were to identify habitat selection and activity patterns of northern Mexican gartersnakes at the hatchery and how frequency of monitoring affects study results. I deployed transmitters on 42 individual gartersnakes and documented macro- and microhabitat selection, daily and seasonal activity patterns, and movement distances. Habitat selection and movements were similar between males and females and varied seasonally. During the active season (March–October), snakes primarily selected wetland edge habitat with abundant cover and were more active and moved longer distances than during other parts of the year. Gestating females selected similar locations but with less dense cover. During the inactive season (November–February), snakes were less mobile and selected upland habitats, including rocky slopes with abundant vegetation. Snakes displayed diurnal patterns of activity. Estimates of daily distance traveled decreased with less-frequent monitoring; a sampling interval of once every 24 hours yielded only 53–62% of known daily distances moved during the active season. These results can help inform management activities and research design. Conservation of this species should incorporate a landscape-level approach that includes abundant wetland edge habitat with connected upland areas. Resource managers and researchers should carefully assess timing and frequency of activities in order to meet project objectives.
ContributorsSprague, Tiffany A (Author) / Bateman, Heather L (Thesis advisor) / Cunningham, Stan C (Committee member) / Jones, Thomas R (Committee member) / Nowak, Erika M. (Committee member) / Arizona State University (Publisher)
Created2017
Description
An organism's ability to maintain optimal body temperature is extremely important for sustaining physiological and behavioral processes necessary for survival. However, like other physiological systems, thermobiology can be influenced by the availability of resources. Water is a vital resource that has profound implications on many aspects of biological function, including thermoregulatory pathways. However, water availability has a tendency fluctuate within any given ecosystem. While several studies have investigated the influence of water availability on a range of thermoregulatory pathways, very little attention has been given to its influence on Voluntary Maximum Temperature (VMT). We investigated the effects of dehydration on Voluntary Maximum Temperature in a captive population of Gila monsters (Heloderma suspectum). Gila monsters are large-bodied, desert dwelling lizards that experience periods of seasonal dehydration. Additionally, the effects of dehydration on their physiology and behavior have been extensively studied. We hypothesized that dehydration would reduce VMT. As expected, there was a significant decrease in exit temperature as blood osmolality increased. This is presumed to be in an effort to decrease water loss. Adaptations that allow desert dwelling organisms to conserve water are highly advantageous due to seasonal water constraints. Our findings offer insight on how the behavior of these organisms may change in response to changes in climate.
ContributorsHartson, Callie Elizabeth (Author) / DeNardo, Dale (Thesis director) / Angilletta, Michael (Committee member) / Camacho, Agus (Committee member) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This 15-week long course is designed to introduce students, specifically in Arizona, to basic sustainability and conservation principles in the context of local reptile wildlife. Throughout the course, the students work on identifying the problem, creating visions for the desired future, and finally developing a strategy to help with reptile species survival in the valley. Research shows that animals in the classroom have led to improved academic success for students. Thus, through creating this course I was able to combine conservation and sustainability curriculum with real-life animals whose survival is directly being affected in the valley. My hope is that this course will help students identify a newfound passion and call to action to protect native wildlife. The more awareness and actionable knowledge which can be brought to students in Arizona about challenges to species survival the more likely we are to see a change in the future and a stronger sense of urgency for protecting wildlife. In order to accomplish these goals, the curriculum was developed to begin with basic concepts of species needs such as food and shelter and basic principles of sustainability. As the course progresses the students analyze current challenges reptile wildlife faces, like urban sprawl, and explore options to address these challenges. The course concludes with a pilot pitch where students present their solution projects to the school.
ContributorsGoethe, Emma Rae (Author) / Brundiers, Katja (Thesis director) / Bouges, Olivia (Committee member) / School of Sustainability (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Understanding how wildlife interact with humans and the built environment is critical as urbanization contributes to habitat change and fragmentation globally. In urban and suburban areas, wildlife and people are often in close quarters, leading to human-wildlife interactions (HWI). In the greater Phoenix Metropolitan Area, Arizona, HWI can involve reptiles such as venomous (family Viperidae, e.g., rattlesnakes) and nonvenomous (family Colubridae, e.g., gophersnakes) snakes. Rattlesnake Solutions, LLC, a local business, removes and relocates snakes from homes and businesses in the Phoenix area and, as a collaborator, has provided records of snake removals. Using these records, I investigated taxa-specific habitat trends at two spatial scales. At the neighborhood scale (n = 60), I found that removals occurred in yards with abundant cover opportunities. At the landscape scale (n = 764), nonvenomous snakes were removed from areas of higher urbanization compared to venomous snakes. Clients of Rattlesnake Solutions, LLC, were asked to answer a short survey, designed by K. Larson and colleagues, regarding the circumstances of their snake removal event and their attitudes, perceptions, and experiences with snakes. I used responses from this survey (n =271) to investigate if prior experience with snakes influences reported attitudes towards snakes. Respondents with prior snake experiences reported more positive attitudes towards snakes and were more consistent across their responses than those without prior snake experiences. Continuing inquiry into the urban ecology of these snakes is important to fostering coexistence between snakes and people that call Phoenix home.
ContributorsEnloe, Annika (Author) / Bateman, Heather L (Thesis advisor) / Lewis, Jesse (Committee member) / Larson, Kelli (Committee member) / Arizona State University (Publisher)
Created2023
Description
Although many studies have identified environmental factors as primary drivers of bird richness and abundance, there is still uncertainty about the extent to which climate, topography and vegetation influence richness and abundance patterns seen in local extents of the northern Sonoran Desert. I investigated how bird richness and abundance differed between years and seasons and which environmental variables most influenced the patterns of richness and abundance in the Greater Phoenix Metropolitan Area.
I compiled a geodatabase of climate, bioclimatic (interactions between precipitation and temperature), vegetation, soil, and topographical variables that are known to influence both richness and abundance and used 15 years of bird point count survey data from urban and non-urban sites established by Central Arizona–Phoenix Long-Term Ecological Research project to test that relationship. I built generalized linear models (GLM) to elucidate the influence of each environmental variable on richness and abundance values taken from 47 sites. I used principal component analysis (PCA) to reduce 43 environmental variables to 9 synthetic factors influenced by measures of vegetation, climate, topography, and energy. I also used the PCA to identify uncorrelated raw variables and modeled bird richness and abundance with these uncorrelated environmental variables (EV) with GLM.
I found that bird richness and abundance were significantly different between seasons, but that richness and winter abundance were not significantly different across years. Bird richness was most influenced by soil characteristics and vegetation while abundance was most influenced by vegetation and climate. Models using EV as independent variables consistently outperformed those models using synthetically produced components from PCA. The results suggest that richness and abundance are both driven by climate and aspects of vegetation that may also be influenced by climate such as total annual precipitation and average temperature of the warmest quarter. Annual oscillations of bird richness and abundance throughout the urban Phoenix area seem to be strongly associated with climate and vegetation.
I compiled a geodatabase of climate, bioclimatic (interactions between precipitation and temperature), vegetation, soil, and topographical variables that are known to influence both richness and abundance and used 15 years of bird point count survey data from urban and non-urban sites established by Central Arizona–Phoenix Long-Term Ecological Research project to test that relationship. I built generalized linear models (GLM) to elucidate the influence of each environmental variable on richness and abundance values taken from 47 sites. I used principal component analysis (PCA) to reduce 43 environmental variables to 9 synthetic factors influenced by measures of vegetation, climate, topography, and energy. I also used the PCA to identify uncorrelated raw variables and modeled bird richness and abundance with these uncorrelated environmental variables (EV) with GLM.
I found that bird richness and abundance were significantly different between seasons, but that richness and winter abundance were not significantly different across years. Bird richness was most influenced by soil characteristics and vegetation while abundance was most influenced by vegetation and climate. Models using EV as independent variables consistently outperformed those models using synthetically produced components from PCA. The results suggest that richness and abundance are both driven by climate and aspects of vegetation that may also be influenced by climate such as total annual precipitation and average temperature of the warmest quarter. Annual oscillations of bird richness and abundance throughout the urban Phoenix area seem to be strongly associated with climate and vegetation.
ContributorsBoehme, Cameron (Author) / Albuquerque, Fabio Suzart (Thesis advisor) / Bateman, Heather L (Committee member) / Saul, Steven E (Committee member) / Arizona State University (Publisher)
Created2019
Description
Land use change driven by human population expansion continues to influence
the integrity and configuration of riparian corridors worldwide. Wildlife viability in semi-arid regions depend heavily on the connectivity of riparian corridors, since water is the primary limiting resource. The Madrean Archipelago in northern Mexico and southwestern United States (US) is a biodiversity hotspot that supports imperiled wildlife like jaguar (Panthera onca) and ocelot (Leopardus pardalis). Recent and ongoing infrastructure developments in the historically understudied US-México borderlands region, such as the border wall and expansion of Federal Highway 2, are altering wildlife movement and disconnecting essential habitat.
I used wildlife cameras to assess species occupancy, abundance, and related habitat variables affecting the use of washes as corridors for mammals in semi-arid Los Ojos (LO), a private ranch within a 530 km2 priority conservation area in Sonora, México located south of the border and Federal Highway 2. From October 2018 to April 2019, I deployed 21 wildlife cameras in five different riparian corridors within LO. I used single- season occupancy models and Royal Nichols abundance models to explore the relationship between habitat variables and use of riparian corridors by mammal communities of conservation concern within this region.
Twenty-one mammal species were recorded in the study area, including American black bear (Ursus americanus), white-tailed deer (Odocoileus virginianus) and the first sighting of jaguar (Panthera onca) in this region in 25 years. For the 11 medium- and large-bodied mammals recorded, habitat variables related to perennial river characteristics (distance to river, weekly water, and site width) and remoteness (distance from highway, elevation, and NDVI) were important for occupancy, but the direction of the relationship varied by species. For commonly observed species such as mountain lion (Puma concolor) and white-nosed coati (Nasua narica), topographic variety was highly informative for species abundance. These results highlight the importance of habitat diversity when identifying corridors for future protection to conserve wildlife communities in semi-arid regions. Additionally, this study provides robust evidence in support of mitigation measures (e.g. funnel fencing, over- or under- passes) along Federal Highway 2, and other barriers such as the border wall, to facilitate wildlife connectivity.
the integrity and configuration of riparian corridors worldwide. Wildlife viability in semi-arid regions depend heavily on the connectivity of riparian corridors, since water is the primary limiting resource. The Madrean Archipelago in northern Mexico and southwestern United States (US) is a biodiversity hotspot that supports imperiled wildlife like jaguar (Panthera onca) and ocelot (Leopardus pardalis). Recent and ongoing infrastructure developments in the historically understudied US-México borderlands region, such as the border wall and expansion of Federal Highway 2, are altering wildlife movement and disconnecting essential habitat.
I used wildlife cameras to assess species occupancy, abundance, and related habitat variables affecting the use of washes as corridors for mammals in semi-arid Los Ojos (LO), a private ranch within a 530 km2 priority conservation area in Sonora, México located south of the border and Federal Highway 2. From October 2018 to April 2019, I deployed 21 wildlife cameras in five different riparian corridors within LO. I used single- season occupancy models and Royal Nichols abundance models to explore the relationship between habitat variables and use of riparian corridors by mammal communities of conservation concern within this region.
Twenty-one mammal species were recorded in the study area, including American black bear (Ursus americanus), white-tailed deer (Odocoileus virginianus) and the first sighting of jaguar (Panthera onca) in this region in 25 years. For the 11 medium- and large-bodied mammals recorded, habitat variables related to perennial river characteristics (distance to river, weekly water, and site width) and remoteness (distance from highway, elevation, and NDVI) were important for occupancy, but the direction of the relationship varied by species. For commonly observed species such as mountain lion (Puma concolor) and white-nosed coati (Nasua narica), topographic variety was highly informative for species abundance. These results highlight the importance of habitat diversity when identifying corridors for future protection to conserve wildlife communities in semi-arid regions. Additionally, this study provides robust evidence in support of mitigation measures (e.g. funnel fencing, over- or under- passes) along Federal Highway 2, and other barriers such as the border wall, to facilitate wildlife connectivity.
ContributorsRagan, Kinley (Author) / Hall, Sharon J (Thesis advisor) / Schipper, Jan (Thesis advisor) / Bateman, Heather L (Committee member) / Arizona State University (Publisher)
Created2020