<p> In the practice of resource management conservation, it is common to introduce new members into small inbred populations in order to increase genetic diversity and reduce the negative effects of inbreeding. Although fitness often increases in the F1 generation immediately following intrapopulation hybridization, few studies have focused on the long-term fitness of such populations. The model organisms <i>Drosophila melanogaster</i> and <i> D. simulans</i> were used to investigate if heterosis, an increase in the fitness in the hybrid population, or outbreeding depression, a decline in the fitness in the hybrid population, occurs over an eight generation period. At each generation, a series of fitness related assays were performed to assess relative fitness. Results of this study were mixed. At best, only some hybridized populations showed slightly higher, but often nonsignificant increases in fitness, never in more than one assay. The lack of consistent strong persistent heterosis suggests that conservation efforts such as habitat preservation maybe be a better use of effort and money for assisting endangered species. </p>

<p> The current biodiversity crisis is challenging the ability of conservation biologists to both monitor ongoing declines and create effective management plans. Ongoing habitat destruction, pollution, introduction of invasive species, and the initial stages of climate change are only some of the anthropogenic stresses that face today's biosphere. On human time scales, these changes are unprecedented, curtailing the availability of knowledge regarding ecological responses to stress and disturbance. The fossil record provides numerous disturbances of varying magnitudes throughout the history of life, and yet this resource has been often overlooked or dismissed by biologists. The purpose of this study is to examine the effects of stress on communities using methods that allow integration of modern and fossil data. With this goal in mind, various levels of disturbance are investigated across increasing temporal and spatial scales.</p><p> At the smallest spatial and temporal scale, I examined the effect of recent lake acidification on plankton communities, using techniques commonly applied by ecologists, as well as introducing a new method based on a well-established technique. Throughout this thesis, I use the Buzas-Gibson evenness metric and Non-metric Multi-Dimensional Scaling analysis (an ordination technique), as well as applying Rank-Abundance Curve Kurtosis, which measures the shape of species-abundance distributions. Each of these techniques is a different way of representing community structure, with each metric providing slightly different information. Within the lake acidification system, all communities displayed a shift in community structure as pH dropped, and again when pH values returned to neutral, indicating a gradual recovery from acid stress. The timing of this change reveals the ability of different communities to resist acidification, and the resilience of those communities through the recovery phase.</p><p> To determine the feasibility of comparing modern and fossil data, I selected four unrelated datasets with distinct disturbance events to represent different time scales, from two decades to one million years. Each dataset displayed a similar pattern; the disturbance event created a distinct shift in community structure followed by a gradual recovery after the stress levels decreased. A major concern when comparing modern and fossil data is the difference in temporal resolution, and specifically the effect of time-averaging which is expected to obscure ecological signals. Instead, I found that applying a model of time-averaging across the community data reduced background noise, thereby clarifying the pattern of ecological change observed in the raw data.</p><p> Extending the temporal and spatial scale, I explored the ecological response of marine microfossil assemblages during three intervals of rapid global warming, as analogues for modern global warming. Four taxonomic groups were included, two benthic and two planktic. Overall, diversity within communities increased during global warming, however this was due to the response of the planktic groups, as both benthic groups showed decreases in diversity. These findings support the utility of the fossil record in examining past disturbances, by providing a useful prediction for biotic responses to global warming.</p><p> Representing the largest spatial and temporal scale is the Botomian mass extinction (mid-Early Cambrian). This mass extinction is the first recognized mass extinction in the history of life, and occurred during an interval of rapid evolution and faunal turnover. During the extinction interval, there was a distinct change in community structure and an associated increase in instability.</p><p> The findings of this study are unique; community structure displays a similar response to stress across various taxonomic groups, in different environments, and at multiple temporal scales. The commonality in community response to stress likely represents a fundamental feature of disturbed ecosystems. Not only is the comparison of modern and fossil data possible, such comparisons offer new discoveries relevant to conservation biology and about the very nature of life on Earth.</p>

<p> Since European colonization, Appalachian culture has been based on resource extraction, such as coal mining, timbering, and Non-Timber Forest Product (NTFP) harvest. Surface mining degrades forest habitat for medicinal plants, especially the habitat for the internationally valuable medicinal herb, American ginseng (<i>Panax quinquefolius</i> L.), and the NTFP culture associated with this plant. The relationship between medicinal plant conservation and surface mining must be studied with a non- traditional, multi-faceted approach: culturally, economically, and ecologically. (1) Using community-based participatory surveys, I determined how ginseng harvesters and non- harvesters in West Virginia communities view the relationship between surface mining and ginseng harvest. Harvester culture is one worth preserving, as they value conservation. However, most harvesters admit to illegal harvesting practices. By determining what harvesters and non-harvesters prioritize and value, and understanding what is the most effective way to connect with these two groups, this research can aid in the development of successful environmental education and conservation outreach. (2) Challenging the perceptions that economic growth is incompatible with ecological consciousness, an economic analysis comparing the short-term gains of surface mining to the potential economic value of sustainable ginseng harvest or a large-scale ginseng farm operation was completed. Through an in-depth economic modeling approach I showed that stewarded ginseng harvest can be economically advantageous in the long-term while maintaining the integrity of the forest. (3) For reintroduction purposes, the concept of &lsquo;indicator species&rsquo; is frequently used. These species are often selected based on anecdotal information, rather than scientific rigor. In order to maximize the efficiency of ginseng reintroductions, I analyzed the ability of select putative indicators (herbs, shrubs, and trees) to serve as site and microsite predictors of ginseng growth. Most indicators were ineffective, and the ones that did show a relationship to growth were contra- indicators, predicting reduced individual plant growth. This research may aid reintroduction and agroforestry projects, and thereby reduce the frequency of reintroductions that fail because plants are introduced into suboptimal locations. (4) By experimentally reintroducing two medicinal plants, ginseng and goldenseal, to two sites with three types of disturbance history, I determined that degraded landscapes can return to a forested state that supports medicinal plant growth and reproduction, although microsite and soil conditions were found to be important to consider when reintroducing plants. As such, appropriate future land-management decisions can be made based on land-use legacy. By combining social, economic, and ecological studies, medicinal plant conservation can be implemented through the development of environmental outreach and effective reintroduction strategies.</p>

<p> As changing ocean conditions lead to declining fish stocks and movement of forage fish, sea lions on the Oregon coast are subject to the pressures of declining prey availability and increasing conflicts with commercial and recreational fisheries. An analysis of strandings of California sea lions, _{Zalophus californianus,} and Steller sea lions, <i>Eumetopias jubatus, </i> from 2006 to 2014, included cause of death, changing ocean conditions, and anthropogenic activity. Causes of death included disease, injury, and human interaction, such as gunshot wounds, fisheries net entanglements and boat strikes. </p><p> Oregon and Washington strandings of California sea lions are primarily adult and subadult males that migrate north from California rookeries, while Steller sea lions are year-round residents and strandings are comprised of males and females of all ages. While the California sea lion population is currently at or near carrying capacity, the Eastern Pacific population of Steller sea lions was designated as Threatened under the Endangered Species Act until October 2013. Understanding impacts to these two pinniped species is vital to implementing effective management and conservation policies.</p><p> Oregon and southern Washington strandings of California sea lions and Steller sea lions from 2006 to 2014 were analyzed spatially using the geographic information system (GIS), and temporally to identify possible correlations with prey availability and human interaction. Strandings were found to follow seasonal patterns from year to year: Steller sea lion strandings were highest from May to July, California sea lions peaked in September, October, and November. There was a correlation between significantly high numbers of strandings and the three largest commercial fisheries in Oregon: Chinook salmon, Coho salmon, and Dungeness crab. </p><p> This analysis provides a format for continuing to monitor primary ecological and anthropogenic drivers of pinniped mortality in Oregon and southern Washington. </p>

<p> <i>Plethodon</i> salamanders may serve as important indicators of forest ecosystem integrity due to their niche, physiological sensitivity, abundance, site fidelity, and association with forest structures. Forest ecosystems provide direct and indirect services and products that benefit society. Monitoring the quality and status of these direct and indirect use values is important to manage and maximize the benefit to people. An ecological indicator is something that may indicate the state of a system. Indicators are widely used in a variety of fields including forestry, economics, and environmental management to monitor the state of desired systems. The IndVal method is a statistical analysis used to determine the efficacy of a species as an indicator species, by determining the association between the species of interest and site groups or habitats. I sought to determine if the red-backed salamander is an indicator of forests based on the IndVal method, and if the red-backed salamander may be used as an indicator of use values. I hypothesized that red-backed salamanders may be used as an indicator of standing mature forested areas. I hypothesized that salamander abundance would be highest in forested areas and may act as an indicator species of forest habitats. I hypothesized that red-backed salamander abundance would have a positive correlation with indirect use values and a negative correlation with direct use values. The study area consisted of Forestland, Timberland, and Agriculture land-uses within northwestern Pennsylvania. I used visual encounter surveys and drift fences for capturing of red-backed salamanders (<i>Plethodon cinereus</i>) for abundance estimates. Visual encounter surveys were done within area constrained (10 &times; 10m) plots and a time constraint of roughly 30 minutes. I measured environmental variables within each plot. An N-mixture model of <i>P. cinereus</i> was used to estimate abundance based on repeated counts data. I used a principal components analysis (PCA) to determine which environmental variables were associated with study sites. I used a Kruskal-Wallis test and post-hoc Dunn&rsquo;s test to determine differences between land-use in red-backed salamander abundance. I applied the IndVal method to red-backed salamander abundance in association to land-use and habitat. I estimated indirect use values through cost replacement methods for water purification, water cycling production, nitrate treatment, and soil erosion. I obtained direct use values through land-owners and the U.S. Forest Service archives, which the cost of production and gross value of production were used to determine the net and gross value. I used a Spearman&rsquo;s Rank correlation to determine the relationship between red-backed salamander abundance and the direct and indirect use values of land-uses. The PCA 1 axis described an environmental gradient of closed to open canopy. Forestland sites had the lowest sunlight values, Agriculture having the highest, and Timberland intermediate between the two. Canopy percent cover was the most informative variable in the N-mixture model. Red-backed salamander abundance was greatest, mean = 434, on Forestland sites and was significantly (p-value &lt; 0.05) different from Timberland and Agriculture. The red-backed salamander was highly associated with Forestland with an indicator species value of 0.876, and 0.972 for forests. Red-backed salamanders held a significant strong positive relationship with indirect use values, rho = 0.84. <i>P. cinereus</i> abundance had a significant strong negative relationship with gross direct use values, rho = &ndash;0.95, and net direct use values, rho = &ndash;0.92. The strong correlation between <i>P. cinereus</i> abundance and indirect use values suggest that red-backed salamander abundance may have applications as an indicator of indirect use values for forest ecosystems.</p><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> Invasive ants are one of the largest threats to Pacific island ecosystem conservation. I investigated effective ant control options by examining the relative attractiveness of five commercial ant baits to yellow crazy ants (<i>Anoplolepis gracilipes</i>). The results were used to select three baits whose efficacy at reducing <i>A. gracilipes</i> abundance was then tested in experimental treatment plots. The trials failed to identify an obvious preference for any of the baits and none of experimental treatments resulted in decreases in <i>A. gracilipes</i> abundance that differed from untreated plots. Additionally, the impact of <i>A. gracilipes</i> on nest initiation rates of Red-tailed Tropicbirds (<i>Phaethon rubricauda </i>) was explored. The survey found 90% fewer nest occurred in plots containing <i>A. gracilipes.</i> These results demonstrate the negative impacts invasive ants can have on ground-nesting seabirds and suggest that commercial ant baits may be ineffective against controlling <i> A. gracilipes</i> supercolonies.</p>

<p> While the processes that led to the formation of modern plant communities are often cryptic, biogeographic patterns of extant species can provide clues to their origin. The Midriff Islands, an archipelago in the Gulf of California at the center of the Sonoran Desert, provide an opportunity to investigate the origins of the desert. This research uses three case studies at three different time scales to better understand the factors responsible for modern biodiversity. </p><p> Chapter 1 revisits the theory of island biogeography and incorporates the long history of humans on the Midriff Islands to determine factors controlling plant species richness. Area, habitat diversity, island type, and seabird dynamics explain 98% of the variability in species richness across this archipelago. Interestingly, human presence is not predictive, suggesting an island system with ancient human interactions that functions in a pre-Anthropocene state. </p><p> Chapter 2 investigates Holocene extinctions. In 1975, bighorn sheep (<i> Ovis canadensis</i>) were introduced as a novel element to Isla Tibur&oacute;n as a conservation measure. Fossil dung found on Isla Tibur&oacute;n was 14C-dated to 1476-1632 years before present and identified as <i>Ovis canadensis </i> by morphological and ancient DNA analysis. Bighorn sheep went locally extinct on the island sometime in the last ~1500 years prior to their "unintentional rewilding." This discovery questions the definition of a non-native species and extends an ecological and conservation baseline. </p><p> Disjunct long-lived plant taxa on Isla Tibur&oacute;n suggests climate and vegetation change on the Midriff Islands in the Pleistocene. Chapter 3 is a phylogeographic study of the desert edge species <i>Canotia holacantha </i> (Celastraceae) that tests whether <i>Canotia</i> on Isla Tibur&oacute;n is a Pleistocene relict or a recent dispersal event. Results suggest long isolation and divergence of <i>Canotia</i> on Tibur&oacute;n but recent arrival in the core of its modern day distribution in Arizona. In contradiction to an expected temperate origin, <i>Canotia</i> seems to have tracked the northward shift of the desert's edge at the end of the last Ice Age from glacial refugia in Sonora or Chihuahua. </p><p> Collectively, this research helps illuminate the history of the desert and establishes baselines to support management decisions of the world's best-preserved archipelago.</p>

Thesis (M.S.)--University of Montana, 2008. / Title from title screen. Description based on contents viewed May 12, 2009. Includes bibliographical references (p. 131-134).

<p> This study provides the first assessment of demographic and habitat information for pinto abalone (<i>Haliotis kamtschatkana</i>) in San Diego, California, two decades after the closure of all abalone fisheries in southern California. SCUBA surveys conducted from June 2014 to December 2016 indicate that current low densities (0-0.03 individuals/m²) were far below critical thresholds identified for other abalone species (0.15-0.30 abalone/m²) for successful spawning and recruitment. A broad range of sizes were represented (13-146 mm), however, only 95 individuals were found. Some sites showed significant aggregation of adult (> 50 mm) pinto abalone, 30% of adults had a nearest-neighbor within a critical spawning distance of 2 m, and 65% had a neighbor within 5 m, indicating that at least a small proportion of individuals may be capable of reproducing successfully. Pinto abalone showed a significant preference for boulder habitat at a lower relief (&lt; 10 cm) relative to available habitat&ndash; a preference that may influence aggregation around habitat features and enhance reproduction. The frequency, timing, and broad spatial distribution of these surveys was not sufficient to measure patterns in recruitment or changes in abundance, particularly over a strong El Ni&ntilde;o event that occurred during the study period. There is a critical need for consistent long-term monitoring in southern California to better understand demographic and environmental processes affecting recovery and persistence of populations, particularly at the southern edge of the broad range of pinto abalone.</p><p>