<p>Body sizes of <i>R. norvegicus</i> trapped (black bars) and predated (gray b... more <p>Body sizes of <i>R. norvegicus</i> trapped (black bars) and predated (gray bars) by cats in Baltimore.</p
ii ACKNOWLEDGEMENTS Financial assistance for this study was provided by the Oklahoma Department o... more ii ACKNOWLEDGEMENTS Financial assistance for this study was provided by the Oklahoma Department of Wildlife Conservation Federal Aid Project W-155-R. Funds were administered through
Background: Community interactions can produce complex dynamics with counterintuitive responses. ... more Background: Community interactions can produce complex dynamics with counterintuitive responses. Synanthropic community members are of increasing practical interest for their effects on biodiversity and public health. Most studies incorporating introduced species have been performed on islands where they may pose a risk to the native fauna. Few have examined their interactions in urban environments where they represent the majority of species. We characterized house cat (Felis catus) predation on wild Norway rats (Rattus norvegicus), and its population effects in an urban area as a model system. Three aspects of predation likely to influence population dynamics were examined; the stratum of the prey population killed by predators, the intensity of the predation, and the size of the predator population. Methodology/Principal Findings: Predation pressure was estimated from the sizes of the rat and cat populations, and the characteristics of rats killed in 20 alleys. Short and long term responses of rat population to perturbations were examined by removal trapping. Perturbations removed an average of 56% of the rats/alley but had no negative long-term impact on the size of the rat population (49.6612.5 rats/alley and 123.8642.2 rats/alley over two years). The sizes of the cat population during two years (3.5 animals/alley and 2.7 animals/alley) also were unaffected by rat population perturbations. Predation by cats occurred in 9/20 alleys. Predated rats were predominantly juveniles and significantly smaller (144.6 g617.8 g) than the trapped rats (385.0 g6135.6 g). Cats rarely preyed on the larger, older portion of the rat population. Conclusions/Significance: The rat population appears resilient to perturbation from even substantial population reduction using targeted removal. In this area there is a relatively low population density of cats and they only occasionally prey on the rat population. This occasional predation primarily removes the juvenile proportion of the rat population. The top predator in this urban ecosystem appears to have little impact on the size of the prey population, and similarly, reduction in rat populations doesn't impact the size of the cat population. However, the selected targeting of small rats may locally influence the size structure of the population which may have consequences for patterns of pathogen transmission.
Movement of individuals promotes colonization of new areas, gene flow among local populations, an... more Movement of individuals promotes colonization of new areas, gene flow among local populations, and has implications for the spread of infectious agents and the control of pest species. Wild Norway rats (Rattus norvegicus) are common in highly urbanized areas but surprisingly little is known of their population structure. We sampled individuals from 11 locations within Baltimore, Maryland, to characterize the genetic structure and extent of gene flow between areas within the city. Clustering methods and a neighbour-joining tree based on pairwise genetic distances supported an east-west division in the inner city, and a third cluster comprised of historically more recent sites. Most individuals (~95%) were assigned to their area of capture, indicating strong site fidelity. Moreover, the axial dispersal distance of rats (62 m) fell within typical alley length. Several rats were assigned to areas 2-11.5 km away, indicating some, albeit infrequent, longdistance movement within the city. Although individual movement appears to be limited (30-150 m), locations up to 1.7 km are comprised of relatives. Moderate F ST , differentiation between identified clusters, and high allelic diversity indicate that regular gene flow, either via recruitment or migration, has prevented isolation. Therefore, ecology of commensal rodents in urban areas and life-history characteristics of Norway rats likely counteract many expected effects of isolation or founder events. An understanding of levels of connectivity of rat populations inhabiting urban areas provides information about the spatial scale at which populations of rats may spread disease, invade new areas, or be eradicated from an existing area without reinvasion.
... Lynne C. Gardner-Santana 1 and Steven J. Beaupre 2. ... collected using radio tracking equipm... more ... Lynne C. Gardner-Santana 1 and Steven J. Beaupre 2. ... collected using radio tracking equipment (Wildlife Materials TRX 100s receiver with a Yagi 3-element directional antenna) and additional T b s by a Lotek SRX 600 scanning datalogger receiver located on a cliff top above ...
Santana, without whose love, guidance, and moral and financial support I would never have complet... more Santana, without whose love, guidance, and moral and financial support I would never have completed this degree. First and foremost, I want to thank her for providing me with warm meals, good company, friendship, and a home that is my safe haven. Her seemingly endless patience with my hectic school schedule and long, long nights of studying and writing so that we could begin our lives together has made this all possible.
.................................................................................................... more ...................................................................................................................... xiv CHAPTER 1. GENERAL INTRODUCTION ..................................................................... 1 Management ...................................................................................................................... 2 History of Management in Iowa ........................................................................................ 3 Use of Population Genetics to Inform Wildlife Management ........................................... 4 Dissertation Organization .................................................................................................. 5 Chapter 2. Genetic Structure of White-Tailed Deer in Iowa: Implications for Disease Spread............................................................................................................... 5 Chapter 3. Influences of Translocation on Contemporary Patterns of White-Tailed Deer Mitochondrial DNA Diversity and Distribution Across Their North American Range ............................................................................................................ 5 Chapter 4. Genetic Similarity of Urban and Rural White-Tailed Deer in Iowa ............ 6 Chapter 5. Genetic Similarity of Captive and Wild White-Tailed Deer in Davis County, Iowa ................................................................................................................. 7 Chapter 6. General Conclusions .................................................................................... 7 References ......................................................................................................................... 7 CHAPTER 2. GENETIC STRUCTURE OF WHITE-TAILED DEER IN IOWA: IMPLICATIONS FOR DISEASE SPREAD ...................................................................... 12 Abstract ........................................................................................................................... 12 Introduction ..................................................................................................................... 13 Methods ........................................................................................................................... 17 Sample Collection ....................................................................................................... 17 Laboratory Methods for Microsatellites ...................................................................... 18 Laboratory Methods for Mitochondrial DNA ............................................................. 19 Summary Statistics ...................................................................................................... 20 Broad Scale Population Genetic Structure .................................................................. 21 Differences in Genetic Structure of Males and Females ............................................. 25 Local Scale Population Genetic Structure ................................................................... 26 Results ............................................................................................................................. 27 Summary Statistics ...................................................................................................... 27 Broad Scale Population Genetic Structure .................................................................. 29
Norway rats are an abundant synanthropic species in urban settings and serve as reservoirs for ma... more Norway rats are an abundant synanthropic species in urban settings and serve as reservoirs for many pathogens. Attempts to control their populations have met with little success. Recent genetic studies suggest that local populations are structured and few individuals move significant distances, but there is substantial gene flow. To understand these observations and their implications on control strategies, we genotyped 722 rats from 20 alleys in Baltimore to establish paternity for 180 embryos. Up to 88 males may have contributed to the litters. All litters were sired by ≥2 males, with an average of 4.9 (range 2-7) males. For dams and sires with known locations, most matings (71.7%; n = 46) occurred among animals from different alleys. The average distance between sires and dams was 114 meters (range 8-352 meters). In 10/17 (58.8%) litters, the majority of the identified sires were captured in different alleys than the females. Sires were significantly less related to females than were the males captured in the females&amp;amp;amp;amp;amp;amp;amp;amp;#39; alleys. Although rats may generally restrict their movements, either receptive females and/or breeding males engage in mate-seeking behaviors that extend beyond movement patterns at other times. This geographically extends the sizes of local populations and buffers them from the impacts of control strategies that focus on local infestations.
<p>Body sizes of <i>R. norvegicus</i> trapped (black bars) and predated (gray b... more <p>Body sizes of <i>R. norvegicus</i> trapped (black bars) and predated (gray bars) by cats in Baltimore.</p
ii ACKNOWLEDGEMENTS Financial assistance for this study was provided by the Oklahoma Department o... more ii ACKNOWLEDGEMENTS Financial assistance for this study was provided by the Oklahoma Department of Wildlife Conservation Federal Aid Project W-155-R. Funds were administered through
Background: Community interactions can produce complex dynamics with counterintuitive responses. ... more Background: Community interactions can produce complex dynamics with counterintuitive responses. Synanthropic community members are of increasing practical interest for their effects on biodiversity and public health. Most studies incorporating introduced species have been performed on islands where they may pose a risk to the native fauna. Few have examined their interactions in urban environments where they represent the majority of species. We characterized house cat (Felis catus) predation on wild Norway rats (Rattus norvegicus), and its population effects in an urban area as a model system. Three aspects of predation likely to influence population dynamics were examined; the stratum of the prey population killed by predators, the intensity of the predation, and the size of the predator population. Methodology/Principal Findings: Predation pressure was estimated from the sizes of the rat and cat populations, and the characteristics of rats killed in 20 alleys. Short and long term responses of rat population to perturbations were examined by removal trapping. Perturbations removed an average of 56% of the rats/alley but had no negative long-term impact on the size of the rat population (49.6612.5 rats/alley and 123.8642.2 rats/alley over two years). The sizes of the cat population during two years (3.5 animals/alley and 2.7 animals/alley) also were unaffected by rat population perturbations. Predation by cats occurred in 9/20 alleys. Predated rats were predominantly juveniles and significantly smaller (144.6 g617.8 g) than the trapped rats (385.0 g6135.6 g). Cats rarely preyed on the larger, older portion of the rat population. Conclusions/Significance: The rat population appears resilient to perturbation from even substantial population reduction using targeted removal. In this area there is a relatively low population density of cats and they only occasionally prey on the rat population. This occasional predation primarily removes the juvenile proportion of the rat population. The top predator in this urban ecosystem appears to have little impact on the size of the prey population, and similarly, reduction in rat populations doesn't impact the size of the cat population. However, the selected targeting of small rats may locally influence the size structure of the population which may have consequences for patterns of pathogen transmission.
Movement of individuals promotes colonization of new areas, gene flow among local populations, an... more Movement of individuals promotes colonization of new areas, gene flow among local populations, and has implications for the spread of infectious agents and the control of pest species. Wild Norway rats (Rattus norvegicus) are common in highly urbanized areas but surprisingly little is known of their population structure. We sampled individuals from 11 locations within Baltimore, Maryland, to characterize the genetic structure and extent of gene flow between areas within the city. Clustering methods and a neighbour-joining tree based on pairwise genetic distances supported an east-west division in the inner city, and a third cluster comprised of historically more recent sites. Most individuals (~95%) were assigned to their area of capture, indicating strong site fidelity. Moreover, the axial dispersal distance of rats (62 m) fell within typical alley length. Several rats were assigned to areas 2-11.5 km away, indicating some, albeit infrequent, longdistance movement within the city. Although individual movement appears to be limited (30-150 m), locations up to 1.7 km are comprised of relatives. Moderate F ST , differentiation between identified clusters, and high allelic diversity indicate that regular gene flow, either via recruitment or migration, has prevented isolation. Therefore, ecology of commensal rodents in urban areas and life-history characteristics of Norway rats likely counteract many expected effects of isolation or founder events. An understanding of levels of connectivity of rat populations inhabiting urban areas provides information about the spatial scale at which populations of rats may spread disease, invade new areas, or be eradicated from an existing area without reinvasion.
... Lynne C. Gardner-Santana 1 and Steven J. Beaupre 2. ... collected using radio tracking equipm... more ... Lynne C. Gardner-Santana 1 and Steven J. Beaupre 2. ... collected using radio tracking equipment (Wildlife Materials TRX 100s receiver with a Yagi 3-element directional antenna) and additional T b s by a Lotek SRX 600 scanning datalogger receiver located on a cliff top above ...
Santana, without whose love, guidance, and moral and financial support I would never have complet... more Santana, without whose love, guidance, and moral and financial support I would never have completed this degree. First and foremost, I want to thank her for providing me with warm meals, good company, friendship, and a home that is my safe haven. Her seemingly endless patience with my hectic school schedule and long, long nights of studying and writing so that we could begin our lives together has made this all possible.
.................................................................................................... more ...................................................................................................................... xiv CHAPTER 1. GENERAL INTRODUCTION ..................................................................... 1 Management ...................................................................................................................... 2 History of Management in Iowa ........................................................................................ 3 Use of Population Genetics to Inform Wildlife Management ........................................... 4 Dissertation Organization .................................................................................................. 5 Chapter 2. Genetic Structure of White-Tailed Deer in Iowa: Implications for Disease Spread............................................................................................................... 5 Chapter 3. Influences of Translocation on Contemporary Patterns of White-Tailed Deer Mitochondrial DNA Diversity and Distribution Across Their North American Range ............................................................................................................ 5 Chapter 4. Genetic Similarity of Urban and Rural White-Tailed Deer in Iowa ............ 6 Chapter 5. Genetic Similarity of Captive and Wild White-Tailed Deer in Davis County, Iowa ................................................................................................................. 7 Chapter 6. General Conclusions .................................................................................... 7 References ......................................................................................................................... 7 CHAPTER 2. GENETIC STRUCTURE OF WHITE-TAILED DEER IN IOWA: IMPLICATIONS FOR DISEASE SPREAD ...................................................................... 12 Abstract ........................................................................................................................... 12 Introduction ..................................................................................................................... 13 Methods ........................................................................................................................... 17 Sample Collection ....................................................................................................... 17 Laboratory Methods for Microsatellites ...................................................................... 18 Laboratory Methods for Mitochondrial DNA ............................................................. 19 Summary Statistics ...................................................................................................... 20 Broad Scale Population Genetic Structure .................................................................. 21 Differences in Genetic Structure of Males and Females ............................................. 25 Local Scale Population Genetic Structure ................................................................... 26 Results ............................................................................................................................. 27 Summary Statistics ...................................................................................................... 27 Broad Scale Population Genetic Structure .................................................................. 29
Norway rats are an abundant synanthropic species in urban settings and serve as reservoirs for ma... more Norway rats are an abundant synanthropic species in urban settings and serve as reservoirs for many pathogens. Attempts to control their populations have met with little success. Recent genetic studies suggest that local populations are structured and few individuals move significant distances, but there is substantial gene flow. To understand these observations and their implications on control strategies, we genotyped 722 rats from 20 alleys in Baltimore to establish paternity for 180 embryos. Up to 88 males may have contributed to the litters. All litters were sired by ≥2 males, with an average of 4.9 (range 2-7) males. For dams and sires with known locations, most matings (71.7%; n = 46) occurred among animals from different alleys. The average distance between sires and dams was 114 meters (range 8-352 meters). In 10/17 (58.8%) litters, the majority of the identified sires were captured in different alleys than the females. Sires were significantly less related to females than were the males captured in the females&amp;amp;amp;amp;amp;amp;amp;amp;#39; alleys. Although rats may generally restrict their movements, either receptive females and/or breeding males engage in mate-seeking behaviors that extend beyond movement patterns at other times. This geographically extends the sizes of local populations and buffers them from the impacts of control strategies that focus on local infestations.
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