<p> Effective conservation strategies for imperiled species require an understanding of processes that influence fitness throughout the organism's life cycle and across the range of habitats needed to complete that cycle. I evaluated factors that affect population viability of bull trout <i>Salvelinus confluentus, </i> a threatened freshwater char species, throughout individual life stages and over the entire life cycle. </p><p> I assessed the relationship between bull trout egg incubation success and environmental variables. Egg survival was negatively related to the percent of fine sediment in redds and positively related to hydraulic conductivity and the strength of downwelling. Next, I quantified juvenile bull trout survival rates and described movement patterns for this life stage. Juvenile bull trout emigrated from natal headwaters into larger rivers throughout the entire year and across a range of sizes. Estimates of juvenile survival rates improved dramatically when emigration was incorporated into the analysis. </p><p> I integrated my observations of bull trout survival, growth, and movement to create a life-cycle model, which I used to better understand how populations respond to changes in specific demographic rates. Bull trout populations were particularly sensitive to changes in juvenile growth and survival. The relative effect of changes to fertility rates and adult survival varied depending upon whether a population was composed primarily of large, migratory, or smaller, resident individuals. Dispersal helped to lower the probability of extinction for small or declining populations when neighboring populations were stable. </p><p> My research demonstrates that bull trout require access to habitats throughout entire watersheds to maintain population viability. My results suggest that limiting anthropogenic sources of fine sediment and maintaining areas of channel complexity that promote downwelling can be important for bull trout embryo survival. Management decisions should also consider the diverse behavior of juvenile bull trout and the wide range of habitat they use. Additionally, connectivity between populations is likely to be important for declining populations to persist. The diversity of life-history strategies expressed by bull trout helps maintain demographic stability within and among populations. As such, preservation of habitat integrity and full life-history diversity is imperative for conservation and recovery of bull trout populations range-wide.</p>

<p> South Florida's loggerhead (<i>Caretta caretta</i>), green (<i>Chelonia mydas</i>) and leatherback (<i>Dermochelys coriacea </i>) sea turtles hatchling have environmentally determined sex. The <i> in situ</i> nest mean hatchling sex ratios (SR) were highly femalebiased: loggerhead <i>F</i>=0.89) and green turtle <i>F</i>=0.81; leatherback's SR was nearly balanced (0.55<i>F</i>). Nest temperatures and SRs differed between leatherbacks and loggerhead and green turtles. The latter two did not differ. The loggerhead response parameters were estimated within biological limitations by both 50-65% of incubation and mean middle 1/3 temperature. The maximum middle 1/3 temperature was the best-fit predictor for green turtles. No best-fit sex ratio-temperature response could be identified for leatherbacks. Clutches incubating under natural conditions can vary greatly in SR; TRT differences may account for differences among species' sex ratios.</p>

<p>The translocation of organisms is becoming a frequently used tool in conservation biology. There are, however, a disproportionate number of unsuccessful attempts translocating populations of herpetofauna. Logistical and temporal limits of monitoring, combined with ambiguous metrics concerning &ldquo;success,&rdquo; have led to few advances regarding reptile translocations. Successfully established and persistent populations are those in which both the founding population and subsequent generations show consistent or positive levels of survival and reproduction. A small population of the threatened Florida Sand Skink (<i>Plestiodon reynoldsi</i>) was translocated in 2007. Data collected from 2007 to 2009 confirmed survival and reproduction among the founding individuals, but the sampling did not include a long enough period to allow for the evaluation of the survival and reproduction of individuals born on the site. In this study, individuals were collected during two separate sampling events, one during the third spring and one during the sixth spring after the translocation occurred. Survival estimates, reproduction, population size and generation structure were calculated by combining and analyzing data from all years post-translocation. The numbers of both total and new individuals captured in the sixth year exceeded captures from every prior sampling event since monitoring began in 2008. Founding individuals represented only 14% of the total individuals captured, while the number of individuals born on site continued to increase. The proportion of recruits and increased number of hatchlings despite the loss of founders shows that the filial generations are producing offspring. The methods utilized in assessing this translocation effort will further the understanding of the population dynamics of the Florida Sand Skink and allow for more informed decisions in future management studies of this threatened species. </p>

<p> Increased agriculture and urbanization in southwestern Illinois have severely fragmented the forests of the region. Habitat fragmentation may cause lower species richness, population declines, or extirpation due to phenomena such as edge effects, inbreeding depression, and stochasticity. The effects of habitat fragmentation on suburban wildlife are poorly understood, especially for small mammals such as the Southern Flying Squirrel (<i>Glaucomys volans</i>). Flying squirrels are arboreal rodents whose presence in a forest is indicative of habitat quality, as this species prefers mature and relatively open forest stands. Flying squirrels can be found in the forested areas of the Southern Illinois University Edwardsville (SIUE) campus. Demographic features of this population and habitat use among forest patches were unknown. Artificial nest boxes were utilized to perform a mark-recapture study of the flying squirrel population as well as examine habitat use. Objectives were to obtain demographic information, and to create a predictive habitat model relating habitat characteristics to presence or absence of nest box materials using logistic regression. Study sites consisted of 145 randomized plots in three forest patches located within the SIUE campus, which were monitored November 2013 through October 2014. A model was generated for combined activity (nesting or feeding materials were present) at plots, which contained forest age, dominance of hard mast at a plot, tree density, topographic position, richness of the shrub layer, and the 90th percentile diameter at breast height. Habitat models were also generated for specified response variables of feeding material presence and nesting material presence. The top model for predicting feeding material presence in a nest box contained dominance of hard mast on a plot, richness of the shrub layer, and basal area of logs. The top model for predicting nesting material presence in a nest box contained the shrub layer stem count, roughness of the nest box tree bark, proximity to edge, cavity count, and the average hard mast dominance in the area surrounding the plot. Models tended to include characteristics regarding hard mast dominance and refugia, suggesting nest box use was influenced by avoidance of predation and food resource availability.</p>

<p> Knowledge of species distribution and habitat associations are essential for conservation measures. Such information is lacking for many marine species due to their occupancy of broad and ephemeral habitats that are difficult to access for study. Sea turtles, specifically the surface&minus;pelagic juvenile stage of some species, are a group for which significant knowledge gaps remain surrounding their distribution and habitat use. Recent research has confirmed the long&minus;standing hypothesis that the surface&minus;pelagic juvenile stage occurs within surface&minus;pelagic drift communities (SPDC). Within the North Atlantic and surrounding basins, the holopelagic macroalgae <i> Sargassum</i> spp. dominates SPDC and serves as a remotely&minus;detectable indicator of SPDC. The present study focuses on surface&minus;pelagic habitats of four sea turtle species and addresses knowledge gaps using two approaches: habitat mapping and behavioral examination. Remote sensing techniques were used to identify SPDC, and satellite telemetry to examine behavior. This work was conducted in three parts and is presented in three chapters. </p><p> Imagery collected from the Landsat satellites (5 and 7) was used to quantify the area of SPDC (km²). Approximately 1,800 Landsat images collected from 2003&ndash;2011 were examined for SPDC. The first chapter discusses the abundance, seasonality, and distribution of SPDC within the eastern Gulf of Mexico waters where surface&minus;pelagic green, hawksbill, Kemp&rsquo;s ridley, and loggerhead turtles are known to occur. SPDC was found year&minus;round within the eastern Gulf of Mexico, and the amount of habitat peaked during summer months. The amount of SPDC within the eastern Gulf of Mexico varied annually with peaks in 2005, 2009, and 2011. High concentrations of SPDC were discovered within offshore waters of the northeastern Gulf of Mexico and southern West Florida Shelf. </p><p> Within the second chapter, the behavior of 10 surface&minus;pelagic juvenile Kemp&rsquo;s ridleys was examined using satellite telemetry. Using remotely&minus;sensed imagery, the sea surface habitats used by tracked turtles were examined. Surface&minus;pelagic juveniles are hypothesized to be principally passive drifters. The behavior of tracked turtles was examined to determine if they exhibited periods of active and passive behavior, which may indicate periods of swim and drift. The proximity of tracked turtles to remotely&minus;detected SPDC was examined when coincident Landsat imagery was available (within one day of the turtle&rsquo;s position). Turtles were tracked for 36.5 days (mean) and exhibited primarily passive behavior during the tracking period. The satellite transmitters messaged frequently and reported temperatures significantly higher than sea surface temperatures. Landsat imagery was available coincident to the tracks of nine individuals. SPDC was present within 74% of images, and the mean distance between tracked turtles and SPDC was 54 km. Close associations between tracked turtles and SPDC were documented for four individuals. Results suggest that the tracked turtles spent a majority of the time drifting within SPDC. </p><p> The final chapter discusses the density of SPDC within northern and western Gulf of Mexico waters from 2009&ndash;2011. Seasonal abundance peaks occurred throughout the study area, but the timing varied. SPDC peaked earlier (late spring) within the northwestern Gulf of Mexico. Moving eastward, the timing of seasonal peaks shifted progressively later during the year. Within the western portions of the study area, SPDC was found to be significantly higher than in the eastern Gulf of Mexico. </p><p> The eastern Gulf of Mexico may provide critical developmental habitats for several North Atlantic sea turtle species. Additional study is necessary to determine if portions of the western Gulf of Mexico could serve in a similar capacity. SPDC is extremely vulnerable to anthropogenic impacts, specifically oil spills and the occurrence of persistent marine debris. Conservation of SPDC may be challenged by its ephemeral nature; however, the results presented herein could advise conservation efforts (e.g., delineation of critical habitat). The present study described spatial patterns of SPDC occurrence, regions of high abundance, and seasonality. The description of the behavior surface&minus;pelagic sea turtles offers refinements to the spatial distribution of this life stage. These results, coupled with information on circulation patterns and the distribution of sea turtle nesting beaches, can be used to better predict when and where sea turtles and SPDC may be found. For example, the year&minus;round persistence of SPDC within the eastern Gulf of Mexico and the location of major nesting beaches located upstream support the area&rsquo;s designation as critical habitat for surface&minus;pelagic green, hawksbill, Kemp&rsquo;s ridley, and loggerhead turtles.</p>

Thesis (doctoral)--Göteborg Universitet, 2006. / Added t.p. with thesis statement inserted. Includes bibliographical references.

<p> Invasive phragmites (<i>Phragmites australis</i>) has encroached on the central Platte River in recent years potentially out-competing native stands of phragmites. Invasive stands are thought to have an overall negative impact on ecosystems, but do provide ecological benefits to some species as food or shelter. Little research has been conducted on its impacts on small mammals. The goals of this project were to identify potential native and invasive stands along the central Platte River and determine small mammals use of invasive phragmites. I examined 35 phragmites samples along the central Platte River using restriction fragment length polymorphism. I used molecular sequencing and morphological features to identify stands. All samples were determined to be invasive. Four study sites along the Platte River were selected to evaluate phragmites use and potential impacts on small mammals. Each study site was in a wooded grassland area and consisted of three patches of invasive phragmites and three patches of wooded grassland vegetation. Study sites were sampled using Sherman live traps from April to October 2014. I found no significant difference in overall small mammal use between vegetation types and no seasonal difference between use of phragmites and wooded grassland stands. I did, however, catch fewer individuals in both habitat types during August. Deer mice (<i> Peromyscus maniculatus</i>) selected native vegetation whereas the white-footed mouse (<i>Peromyscus leucopus</i>), meadow vole (<i>Microtus pennsylvanicus</i>) hispid cotton rat (<i>Sigmodon hispidus</i>) and meadow jumping mouse (<i>Zapus hudsonius</i>) selected phragmites. Capture of hispid cotton rat was the first documentation of this species in Dawson County, Nebraska. Differences in selection by these species could be attributed to their different life histories or habitat preferences. The focus of management for invasive phragmites may not need to focus on total eradication. Additional sampling would be required to document the spatial extent of native phragmites stands along the central Platte River.</p>

<p>Amphibian populations have been declining at higher rates than bird and mammal populations. Agriculture, urbanization, including roads, and resource extraction continue to put pressure on all species. Roads in particular, are major sources of mortality. The Santa Cruz long-toed salamander (<i> Ambystoma macrodactylum croceum</i>), one of the most critically endangered species in the US, is one amphibian that is declining as a result of anthropogenic impacts, especially habitat loss and fragmentation due to urban development. Migration across roads puts these salamanders at risk from road-related death. This thesis quantified the rate of road mortality to these salamanders and other common amphibians during two A. m. croceum breeding-migration seasons in 2011&ndash;13 in a portion of the subspecies' range. Vehicular traffic was a major source of mortality to the salamander. Through traffic doubled the overall vehicle load on roads where the <i>A. m. croceum</i> migrated to and from breeding ponds. The Pacific chorus frog was also killed on the roads. This common species can be used as an indicator of road mortality risk for rarer amphibians. This study indicated that measures to reduce road mortality to the Santa Cruz long-toed salamander could include restricting vehicular traffic on roads adjacent to salamander ponds by limiting traffic to residential use only during breeding migrations, installing structures to protect <i>A. m. croceum</i> while crossing roads, and potentially assisting animals crossing roads at nighttime during the breeding migrations. </p>

<p> Factors associated with rank position are poorly understood whereas even fewer studies assessed if benefits were associated with increased rank position when resources were unlimited. I assessed whether age, body mass, size, and testosterone levels were important in rank establishment among 132 captive female white-tailed deer (<i>Odocoileus virginianus</i>. I also assessed if the benefit metrics of improved body condition, decreased stress level, and earlier parturition date were related to rank position. Deer in each of 9 study pens had a linear hierarchy with a mean h' of 0.39 (SD = 0.09). Rank position was moderately related to age (P &lt; 0.1) and was strongly related to body mass and size (P &lt; 0.01). There was no relationship between benefit metrics and rank position (P &lt; 0.1). Although increased body mass, size, and age improved rank position there were no benefits associated with increased rank when resources were unlimited.</p>

<p> For mule deer (<i>Odocoileus hemionus</i>) in the Intermountain West, alterations to habitat are outpacing strategies to mitigate human disturbance on critical seasonal ranges and migration routes. </p><p> Conserving mule deer habitat requires cooperation between a diverse group of stakeholders, state wildlife agencies, and federal land management agencies. The first chapter of this thesis explores the current and historical relationship between state wildlife agencies, citizen stakeholders, and federal agencies in order to highlight opportunities to improve cooperative habitat conservation in the United States. Conservation is a result of social, political, and economic action, but relies upon science to inform policy. The second chapter explores the seasonal habitat use of mule deer in southwestern Wyoming. In response to low fawn recruitment, the Wyoming Game and Fish Department deployed 15 GPS collars on adult female mule deer in an effort to enhance knowledge of mule deer population dynamics, migrations, and habitat use. The study captured two winter climate regimes, with greater winter severity during the 2010-11 winter compared to the winter of 2011-12. Deer migrated an average of 23.9 km (SE = 2.2) between seasonal ranges, and completed spring migrations nearly one month earlier following the milder winter of 2011-12 (<i>t</i>19 = 5.53, df = 19, <i>P</i> &le; 0.001). Pooled, the average area of winter ranges (1057 ha, SE = 103, <i>n</i> = 26) was larger than summer ranges (423 ha, SE = 51 ha, <i>n</i> = 25) (<i>t</i> = &minus;5.44, df = 49, <i>P</i> &amp;le; 0.001), with no increase or decrease in size of seasonal ranges detected between years (<i>P</i> = 0.243) according to a post-hoc Tukey HSD test. Between years, deer were observed to shift the geographic center of winter ranges (2.9 km, SE = 1.1, <i> n</i> = 12) to a larger degree than summer ranges (0.4 km, SE = 0.1, <i> n</i> = 12) (<i>t</i> = &minus;2.20, df = 22, <i>P</i> = 0.040). Survival and pregnancy rates (86% and 96%, respectively) correlated closely with other mule deer studies, and neither factor appears to negatively impact population growth. </p><p> Identifying seasonal ranges and migration routes, and quantifying seasonal habitat use, will assist Wyoming Game and Fish Department efforts to protect mule deer seasonal habitats and migration routes, and direct vegetation manipulations intended to improve the nutritional quality of habitats. On average, winter ranges included a later percentage of shrub-dominated habitat (83.8%, SE = 0.3, <i>n</i> = 26) than summer ranges (57.5%, SE = 2.0, <i> n</i> = 25) (<i>t</i> = &minus;4.42, df = 49, <i>P</i> &le; 0.001). Summer ranges averaged a greater proportion of agricultural lands (2.8%, SE = 1.1, <i>n</i> = 25) and aspen (<i>Populus tremuloides </i>) habitats (9.0%, SE = 2.2, <i>n</i> = 25) than winter ranges (0.1%, SE = 0.1, <i>n</i> = 26 and 0.2%, SE = 0.0, <i> n</i> = 26, respectively) (<i>t</i> = 3.03, df = 49, <i>P</i> = 0.004 and <i>t</i>= 3.86, df = 49, <i> P</i> &le; 0.001, respectively). Mule deer ranges are primarily located on Bureau of Land Management (73%, SE = 2.8, <i>n</i> = 51) and privately owned (17.3%, SE = 2.9, <i>n</i> = 51) lands, highlighting opportunities for cooperative partnerships for mule deer habitat conservation. </p>