Cold, Dry, and Alone: Quantifying Hibernation Traits in Dryland Bats of the Southwest

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Description
As white-nose syndrome (WNS) spreads across North America, generating baseline data on bats hibernating outside of the affected area is critical. To illustrate, despite the imminent arrival of Pseudogymnoascus destructans (Pd) to Arizona (AZ), little is known about bat hibernation…

As white-nose syndrome (WNS) spreads across North America, generating baseline data on bats hibernating outside of the affected area is critical. To illustrate, despite the imminent arrival of Pseudogymnoascus destructans (Pd) to Arizona (AZ), little is known about bat hibernation in the Southwest. With the current amount of information, if Pd spreads throughout the state, detection of cases would be limited, and severity of disease and magnitude of mortality impossible to accurately estimate. Thus, my study monitored hibernating bats in AZ to increase knowledge and investigate potential WNS impacts on these populations. Utilizing passive acoustic monitoring, internal cave surveys, environmental monitoring, and thermal imaging, my study quantified microclimate preferences, hibernation lengths, hibernation behaviors, population dynamics, and species compositions of bats hibernating in three north-central AZ caves. Hibernation lasted between 104 and 162 days, from late October through mid- March, during which time bats (primarily Corynorhinus townsendii and Myotis species) roosted at locations with an average of 4.7oC (range = -0.2oC – 12.1oC), 59.6% relative humidity (range = 39.6% - 75.9%), and 0.4 kPa water vapor pressure deficit (range = 0.2 kPa – 0.8 kPa). A maximum of 40 individuals were observed in any hibernacula and clustering behavior occurred in only 4.1% of torpid bats. Bats selected cold and dry roost sites within caves. Results suggest Pd could proliferate on some bats hibernating in colder areas of AZ hibernacula, yet the range of observed roost humidities was lower than optimal for Pd growth. Hibernation length in north-central AZ is longer than predicted for Myotis species at similar latitudes and may be long enough to pose over- winter survival risks if WNS emerges in AZ populations. Yet, a natural tendency for mid-winter activity, which I observed by multiple species, may allow for foraging opportunities and water replenishment, and therefore promote survival in bats utilizing these arid and cold habitats in winter. Additionally, the relatively solitary behaviors I observed, including virtually no clustering activity and a maximum of 40 bats per hibernacula, may keep rates of Pd transmission low in these Southwest bat populations.
Date Created
2023
Agent

Snake Removals, Residential Yards, and Resident Attitudes Towards Snakes in the Phoenix Metropolitan Area, Arizona

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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…

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.
Date Created
2023
Agent

Neighborhood Ethnicity is Related to Occupancy of Mammals Across a Diverse Metropolitan Area

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Description
More people live in cities or metropolitan areas than ever before, which encompass many types of urbanization. These areas are culturally diverse and densely populated heterogeneous landscapes that are shaped by socio-ecological patterns. Cities support human and wildlife populations that…

More people live in cities or metropolitan areas than ever before, which encompass many types of urbanization. These areas are culturally diverse and densely populated heterogeneous landscapes that are shaped by socio-ecological patterns. Cities support human and wildlife populations that are influenced indirectly and directly by human decisions. This process can result in unequal access to environmental services and accessible green spaces. Additionally, biodiversity distribution is influenced by human decisions. Although neighborhood income can drive biodiversity in metropolitan areas (i.e., the ‘luxury effect’), other socio-cultural factors may also influence the presence and abundance of wildlife beyond simple measures of wealth. To understand how additional social factors shape distributions of wildlife, I ask, are patterns of wildlife distribution associated with neighborhood ethnicity, in addition to income and ecological landscape characteristics within metropolitan areas? Utilizing data from 38 wildlife cameras deployed in neighborhood public parks and non-built spaces in metro Phoenix, AZ (USA), I estimated occupancy and activity patterns of coyotes (Canis latrans), desert cottontail rabbits (Sylvilagus audubonii), and domestic cats (Felis catus) across gradients of median household income and neighborhood ethnicity, estimated by the proportion of Latinx residents. Neighborhood ethnicity appeared in the top models for all species, and neighborhood % of Latinx residents was inversely associated with presence of native Sonoran Desert animals (coyotes and cottontail rabbits). Furthermore, daily activity patterns of coyotes differed in neighborhoods with higher vs. lower proportion of Latinx residents. My results suggest that socio-cultural variables beyond income are associated with wildlife distributions, and that factors associated with neighborhood ethnicity may be an informative correlate of city-wide ecological patterns. In this research, I unraveled predictive social variables and differentiated wildlife distribution across neighborhood gradients of income and ethnic composition, bringing attention to the potentially unequal distribution of mammals in cities.
Date Created
2022
Agent

The Effects of the COVID-19 Pandemic on Human Activity and Coyote Populations Along the Gradient of Urbanization

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Description

Humans can influence wildlife populations and behavior through structural and behavioral disturbances, which can be particularly pronounced along the gradient of urbanization. Importantly, although anthropogenetic structural characteristics are relatively static along the gradient of urbanization for a given period of…

Humans can influence wildlife populations and behavior through structural and behavioral disturbances, which can be particularly pronounced along the gradient of urbanization. Importantly, although anthropogenetic structural characteristics are relatively static along the gradient of urbanization for a given period of time, the presence of humans can be dynamic on daily and seasonal scales, which can affect wildlife activity patterns. The rapid onset of the COVID-19 pandemic created a unique opportunity to evaluate how a sudden change in human behavior can affect wildlife activity along the urbanization gradient. Specifically, we used a before-after-control-impact (BACI) study design to compare human presence and coyote daily activity patterns from before the COVID-19 pandemic to after COVID-19 stay-at-home orders and shutdowns were put in place in areas of low and high levels of urbanization. We predicted that human detection rates would increase in low levels of urbanization and decrease in high levels of urbanization due to the COVID-19 pandemic shutdowns. We also predicted that coyote daily activity patterns would shift in response to human detection rates, where coyotes would become more nocturnal in areas of low levels of urbanization where human presence was expected to increase and become more diurnal in areas of high levels of urbanization where human presence was expected to decrease. We used data from wildlife cameras across the gradient of urbanization from 2019 to 2020 within the Phoenix Valley of Arizona. Across 8 sites in low levels of urbanization and 12 sites in high levels of urbanization, we did not find a statistical difference in human detection rates or coyote activity patterns in response to the COVID-19 pandemic. However, low sample size likely led to low power to detect differences and next steps for this research (as part of my M.S. thesis project) will be incorporating additional wildlife camera locations and wildlife species (e.g., bobcat, cottontail rabbit, gray fox, etc.), into future analyses. This project and future studies can help us better understand how structural and behavioral characteristics of humans can shape wildlife populations along the gradient of urbanization, which has important conservation implications for wildlife and people.

Date Created
2022-05
Agent

Responses of mammals to native and non-native riparian forest types in Southeastern Arizona

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Description
Riparian areas are an important resource, especially in the arid southwest, for many wildlife species. Understanding species occurrence in areas dominated by non-native vegetation is important to determine if management should be implemented. Saltcedar (Tamarix spp.) is one of the…

Riparian areas are an important resource, especially in the arid southwest, for many wildlife species. Understanding species occurrence in areas dominated by non-native vegetation is important to determine if management should be implemented. Saltcedar (Tamarix spp.) is one of the most prevalent non-native trees in riparian areas in the southwest United States and can alter vegetation structure, but little is known about how medium and large carnivores use stands of saltcedar. Three riparian forest types make up the San Pedro riparian corridor: non-native saltcedar, native mesquite (Prosopis spp.) bosque, and a mixture of native cottonwood (Populus fremontii) and willow (Salix goodingii) woodlands. My goals were to determine relative use, diversity, and occupancy of medium and large mammals across forest types to evaluate use of the non-native stands. I sampled mammals along approximately 25.7 river kilometers between July 2017 and October 2018, using 18 trail cameras (six per forest type) spaced 1km apart. I summarized environmental variables around the camera sites to relate them to species occupancy and reduced them to 4 components using a Principal Component Analysis (PCA). I observed 14 carnivore species, including bobcat (Lynx rufus), coyote (Canis latrans), and coati (Nasua narica) over 7,692 trap nights. Occupancy of some species may have been influenced by the different components, but models showed high standard errors, making it difficult to draw firm conclusions. Most mammal species used all three forest types at some level and no surveyed forest type was completely avoided or unused. Coyote tended to have greater use in the mesquite forest while canids trended toward greater use in saltcedar forest. Based on two-species occupancy models as well as activity overlap patterns, subordinate species did not appear to avoid dominant species. No species seems significantly affected by non-native saltcedar at this time.
Date Created
2019
Agent

Jaguar (Panthera onca) Habitat Suitability Assessment in the Wildlife Corridor Linking the Talamanca Mountains to the Coastal Forests of the Osa Peninsula

Description
Anthropogenic land-use change, and its resulting habitat fragmentation, have restricted and isolated jaguar (Panthera onca) populations across their historic range of South, Central, and North America. As a result, jaguar are now globally listed as Near Threatened by the IUCN…

Anthropogenic land-use change, and its resulting habitat fragmentation, have restricted and isolated jaguar (Panthera onca) populations across their historic range of South, Central, and North America. As a result, jaguar are now globally listed as Near Threatened by the IUCN Red List of threatened species (Quigley et al., 2017). Southwestern Costa Rica maintains two distinct jaguar populations: a small relictual “sink” population in Corcovado National Park on the Osa Peninsula and a larger but marginalized “source” population in the La Amistad International Park in the Talamanca mountains to the Northeast. The small and highly restricted population located between Corcovado (425 km²) and Piedras Blancas (140 km²) National Parks has been isolated for more than 50 years, while La Amistad International Park (2306 km²) in the north contains a significantly larger population, but in suboptimal montane habitat. A mosaic of pastures, coffee plantations, African oil palm groves, pineapple plantations, and human communities separate these two populations. My paper offers an analysis of the habitat suitability between the montane forest of the Talamanca Mountains and the coastal forest of the Osa Peninsula for jaguars within a proposed conservation corridor. While forest was determined to be the most optimal habitat type for jaguar, mangroves and small scale coffee were also found to be suitable in the context of a corridor. Palm was identified as having marginal suitability, while pasture and pineapple appeared poorly suited for jaguar, particularly due to the lack of prey species and vegetation cover. Urban areas were found to be entirely unsuitable. While human activities have highly fragmented the study area, my analysis suggests that human-dominated landscapes, such as agriculture, can still maintain connectivity, especially when paired with actions to improve conservation, education, and sustainable practices. My research will further support the establishment of a proposed wildlife corridor, which could greatly improve connectivity for wildlife across the region and facilitate movement of jaguar and prey species between the isolated Talamancan and Osa populations.
Date Created
2019-05
Agent
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