With exploding human populations and landscapes that are changing, an increasing number of wildlife species are brought to the brink of extinction. In Canada, the eastern hog-nosed snake, 'Heterodon platirhinos', is found in a limited portion of southern Ontario. Designated as threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), this reptile has been losing its habitat at an alarming rate. Due to the increase in development of southern Ontario, it is crucial to document what limits the snake’s habitat to direct conservation efforts better, for the long-term survival of this species. The goals of this study are: 1) to examine what environmental parameters are linked to the presence of the species at a landscape scale; 2) to predict where the snakes can be found in Ontario through GIS-based habitat suitability models (HSMs); and 3) to assess the role of biotic interactions in HSMs. Three models with high predictive power were employed: Maxent, Boosted Regression Trees (BRTs), and the Genetic Algorithm for Rule-set Production (GARP). Habitat suitability maps were constructed for the eastern hog-nosed snake for its entire Canadian distribution and models were validated with both threshold dependent and independent metrics. Maxent and BRT performed better than GARP and all models predict fewer areas of high suitability when landscape variables are used with current occurrences. Forest density and maximum temperature during the active season were the two variables that contributed the most to models predicting the current distribution of the species. Biotic variables increased the performance of models not by representing a limiting resource, but by representing the inequality of sampling and areas where forest remains. Although habitat suitability models rely on many assumptions, they remain useful in the fields of conservation and landscape management. In addition to help identify critical habitat, HSMs may be used as a tool to better manage land to allow for the survival of species at risk.

abstract: The Southwestern Willow Flycatcher (Empidonax traillii extimus) has been studied for over two decades and listed as endangered for most of that time. Though the flycatcher has been granted protected status since 1995, critical habitat designation for the flycatcher has not shared the same history. Critical habitat designation is essential for achieving the long-term goals defined in the flycatcher recovery plan where emphasis is on both the protection of this species and "the habitats supporting these flycatchers [that] must be protected from threats and loss" (U.S. Fish and Wildlife Service 2002). I used a long-term data set of habitat characteristics collected at three study areas along the Lower Colorado River to develop a method for quantifying habitat quality for flycatcher. The data set contained flycatcher nest observations (use) and habitat availability (random location) from 2003-2010 that I statistically analyzed for flycatcher selection preferences. Using both Pearson's Chi-square test and SPSS Principal Component Analysis (PCA) I determined that flycatchers were selecting 30 habitat traits significantly different among an initial list of 127 habitat characteristics. Using PCA, I calculated a weighted value of influence for each significant trait per study area and used those values to develop a habitat classification system to build predictive models for flycatcher habitat quality. I used ArcGIS® Model Builder to develop three habitat suitability models for each of the habitat types occurring in western riparian systems, native, mixed exotic and exotic dominated that are frequented by breeding flycatchers. I designed a fourth model, Topock Marsh, to test model accuracy on habitat quality for flycatchers using reserved accuracy assessment points of previous nest locations. The results of the fourth model accurately predicted a decline in habitat at Topock Marsh that was confirmed by SWCA survey reports released in 2011 and 2012 documenting a significant decline in flycatcher productivity in the Topock Marsh study area. / Dissertation/Thesis / M.S. Applied Biological Sciences 2013

With exploding human populations and landscapes that are changing, an increasing number of wildlife species are brought to the brink of extinction. In Canada, the eastern hog-nosed snake, 'Heterodon platirhinos', is found in a limited portion of southern Ontario. Designated as threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), this reptile has been losing its habitat at an alarming rate. Due to the increase in development of southern Ontario, it is crucial to document what limits the snake’s habitat to direct conservation efforts better, for the long-term survival of this species. The goals of this study are: 1) to examine what environmental parameters are linked to the presence of the species at a landscape scale; 2) to predict where the snakes can be found in Ontario through GIS-based habitat suitability models (HSMs); and 3) to assess the role of biotic interactions in HSMs. Three models with high predictive power were employed: Maxent, Boosted Regression Trees (BRTs), and the Genetic Algorithm for Rule-set Production (GARP). Habitat suitability maps were constructed for the eastern hog-nosed snake for its entire Canadian distribution and models were validated with both threshold dependent and independent metrics. Maxent and BRT performed better than GARP and all models predict fewer areas of high suitability when landscape variables are used with current occurrences. Forest density and maximum temperature during the active season were the two variables that contributed the most to models predicting the current distribution of the species. Biotic variables increased the performance of models not by representing a limiting resource, but by representing the inequality of sampling and areas where forest remains. Although habitat suitability models rely on many assumptions, they remain useful in the fields of conservation and landscape management. In addition to help identify critical habitat, HSMs may be used as a tool to better manage land to allow for the survival of species at risk.

The Wright fishhook cactus (Sclerocactus wrightiae L.D. Benson) is an endangered cactus species endemic to south-central Utah. Since its listing in 1979 by the U.S. Fish and Wildife Service, the potential impacts of soil disturbance by cattle have become a central focus of management policies and monitoring efforts. However, little to no empirical data has been collected to substantiate the hypothesis that soil disturbance by cattle has direct or indirect negative effects on Wright fishhook cactus growth or reproduction. Over the years, the Bureau of Land Mangement (BLM) and Capitol Reef National Park (CRNP) have invested significant resources documenting cactus populations including several attributes of individual cacti: GPS location, diameter, number of flowers, fruits, or buds, number of stems, and the presence or absence of a cow track within 15 cm of the cactus. While these efforts have been commendable, due to the defining phenological characteristics of this species (flower and filament color) and its short flowering period (April-May) it remains difficult to study and much basic biological information including a range wide population estimate and defined critical habitat remain unknown. Our research had two primary objectives, 1) evalutate the effects of soil disturbance by cattle on reproduction and diameter of the Wright fishhook cactus (Chapters 1 and 2), and 2) explore the use of drones and GIS to define critical habitat and obtain an accurate range wide population estimate (Chapters 3 and 4). In Chapter 1, we analyzed cactus attribute data collected by the BLM at 30 macro-plots representing different levels of soil related cattle disturbance (high, moderate, and low) from 2011-2017. We found no significant association between level of cattle disturbance and flower density or cactus diameter. We did find a significant negative association between flower frequency and increased disturbance. In Chapter 2, we conducted an experimental study where tracks were simulated within 15 cm of cacti at various levels (Ctrl, 1-Track, 2-Track, 4-Tracks, and 4-Tracks Doubled). No significant association was observed between the number of tracks and response in diameter, flower production, fruit production, or seed set. In Chapter 3, we conducted drone flights over 14 macro-plots at three different altitudes above ground level (10 m, 15 m, and 20 m) and found that while the 10 m flights provided the best remotely sensed survey results, drones are not a suitable replacement for ground censuses. In Chapter 4, we used Resource Selection Function to define critical habitat for the Wright fishhook cactus. Our modeling suggests that geology, elevation, and slope are significant factors in defining cactus habitat. Based on the results of our research we conclude that soil disturbance by cattle may not have a significant influence on Wright fishhook cactus populations or dynamics, and that accurate range wide population estimates may be best obtained through ground surveys within the predicted critical habitat.

The Wright fishhook cactus (Sclerocactus wrightiae L.D. Benson) is an endangered cactus species endemic to south-central Utah. Since its listing in 1979 by the U.S. Fish and Wildife Service, the potential impacts of soil disturbance by cattle have become a central focus of management policies and monitoring efforts. However, little to no empirical data has been collected to substantiate the hypothesis that soil disturbance by cattle has direct or indirect negative effects on Wright fishhook cactus growth or reproduction. Over the years, the Bureau of Land Mangement (BLM) and Capitol Reef National Park (CRNP) have invested significant resources documenting cactus populations including several attributes of individual cacti: GPS location, diameter, number of flowers, fruits, or buds, number of stems, and the presence or absence of a cow track within 15 cm of the cactus. While these efforts have been commendable, due to the defining phenological characteristics of this species (flower and filament color) and its short flowering period (April-May) it remains difficult to study and much basic biological information including a range wide population estimate and defined critical habitat remain unknown. Our research had two primary objectives, 1) evalutate the effects of soil disturbance by cattle on reproduction and diameter of the Wright fishhook cactus (Chapters 1 and 2), and 2) explore the use of drones and GIS to define critical habitat and obtain an accurate range wide population estimate (Chapters 3 and 4). In Chapter 1, we analyzed cactus attribute data collected by the BLM at 30 macro-plots representing different levels of soil related cattle disturbance (high, moderate, and low) from 2011-2017. We found no significant association between level of cattle disturbance and flower density or cactus diameter. We did find a significant negative association between flower frequency and increased disturbance. In Chapter 2, we conducted an experimental study where tracks were simulated within 15 cm of cacti at various levels (Ctrl, 1-Track, 2-Track, 4-Tracks, and 4-Tracks Doubled). No significant association was observed between the number of tracks and response in diameter, flower production, fruit production, or seed set. In Chapter 3, we conducted drone flights over 14 macro-plots at three different altitudes above ground level (10 m, 15 m, and 20 m) and found that while the 10 m flights provided the best remotely sensed survey results, drones are not a suitable replacement for ground censuses. In Chapter 4, we used Resource Selection Function to define critical habitat for the Wright fishhook cactus. Our modeling suggests that geology, elevation, and slope are significant factors in defining cactus habitat. Based on the results of our research we conclude that soil disturbance by cattle may not have a significant influence on Wright fishhook cactus populations or dynamics, and that accurate range wide population estimates may be best obtained through ground surveys within the predicted critical habitat.

No description available.

Understanding how populations are structured and how they use natural and anthropogenic spaces is essential for effective wildlife management. A total of 510 barren-ground (Rangifer tarandus groenlandicus), 176 boreal (R. t. caribou), 11 mountain woodland (R. t. caribou), and 39 island (R. t. groenlandicus x pearyi) caribou were tracked with satellite collars in 1993-2009 in the Northwest Territories, Nunavut, and northern Alberta. Using satellite location data and hierarchical and fuzzy cluster analyses, I verified that Cape Bathurst, Bluenose-West, Bluenose-East, Bathurst, Beverly, Qamanirjuaq, and Lorillard barren-ground subpopulations were robust; the Queen Maude Gulf and Wager Bay barren-ground subpopulations were distinct. Dolphin and Union island caribou formed one population; boreal caribou formed two distinct subpopulations. Females in robust subpopulations were structured by strong annual spatial affiliation; those in distinct subpopulations were spatially independent and structured by migratory connectivity, movement barriers, and/or habitat discontinuity. An east-west cline in annual-range sizes and path lengths supported the subpopulation structure identified for migratory barren-ground caribou. I analyzed satellite location data to determine parturition dates and activity periods for all caribou ecotypes. For parturition dates I found a north-south cline for boreal caribou, west-east cline for migratory barren-ground caribou, and ecotype and subspecies clines for boreal and barren-ground caribou. Based on annual changes in movement rates I identified eight activity periods for boreal and tundra-wintering, 10 for mountain woodland, and 12 for migratory barren-ground caribou. Based distribution and movements, boreal caribou avoided seismic lines during periods when females and calves were most vulnerable to predators or hunters. They crossed fewer seismic lines and travelled faster when they crossed them than expected. Caribou avoided areas ≤400 m from seismic lines where they could space away from them suggesting that they perceive these as risky areas. I defined secure habitats as areas that were >400 m from anthropogenic linear features. Population growth rates were higher in areas where they had access to secure unburned habitat and where most of that was in patches >500 km2. Critical habitat for boreal caribou is a habitat state that provides “security” from predation risk and facilitates the effectiveness of their anti-predator strategies. / Ecology