Minnows and darters are the most imperiled freshwater fish species in North America as a result of habitat degradation and restricted ranges, which often results in isolated populations. The Candy Darter Etheostoma osburni was recently listed as Endangered and may represent a suite of other imperiled fishes in terms of their ecology, life-history traits, and conservation needs. I examined the effects of microhabitat features, sampling effort, species abundance and morphology on riffle-dwelling species. My results confirm many of the well-known influences on detection, while adding to the knowledge of species-specific attributes that can influence detection of common riffle species. Using physical marking and molecular methods, I describe movement patterns and provide insight into the spatial distribution of related pairs and reproductive contribution of the endangered Candy Darter. Minimum detected movements of adults were greater for molecular methods than for visual markings. Indirect movements inferred from the spatial extent between related pairs indicated that parents and offspring move along their entire 18.8-km distribution in Stony Creek, while individual parents and offspring in Laurel Creek move throughout half of their 4.25-km distribution. Additionally, I provide evidence that the lifetime reproductive contribution of Candy Darter is greater than previously described. Using microsatellite DNA markers, I describe population genetic structure and estimate effective population sizes of the four extant populations of Candy Darter in Virginia and provide insight into which populations may be successful as sources for reintroduction or translocation efforts. The four extant populations in Virginia are demographically isolated, but results also suggest historical connectivity. Effective population estimates for all populations were less than the recommended 500 to maintain evolutionary potential, but three populations numbered > 130, indicating they may be viable options for source populations for translocations. My results suggest that all populations may benefit from translocations to overcome genetic drift and inbreeding and to safeguard the historical genetic variation of the species. / Master of Science / Minnows and darters are the most imperiled freshwater fish species in North America as a result of habitat degradation and restricted ranges, which often results in isolated populations. The Candy Darter Etheostoma osburni was recently listed as Endangered and may represent a suite of other imperiled fishes in terms of their ecology, life-history traits, and conservation needs. I examined the effects of microhabitat features, sampling effort, species abundance and morphology on riffle-dwelling species. My results confirm many of the well-known influences on detection, while adding to the knowledge of species-specific attributes that can influence detection of common riffle species. Using physical marking and molecular methods, I describe movement patterns and provide insight into the spatial distribution of related pairs and reproductive contribution of the endangered Candy Darter. Minimum detected movements of adults were greater for molecular methods than for visual markings. Indirect movements inferred from the spatial extent between related pairs indicated that parents and offspring move along their entire 18.8-km distribution in Stony Creek, while individual parents and offspring in Laurel Creek move throughout half of their 4.25-km distribution. Additionally, I provide evidence that adult Candy Darter successfully reproduce over a greater number of years than previously described. Using microsatellite DNA markers, I describe population genetic structure and estimate the number of individuals contributing the gene pool of the four extant populations of Candy Darter in Virginia and provide insight into which populations may be successful as sources for reintroduction or translocation efforts. The four extant populations in Virginia are reproductively isolated, but results also suggest historical connectivity. The numbers of individuals contributing to population-specific gene pools were less than the recommended 500 to maintain evolutionary potential, but three populations numbered > 130, indicating they may be viable options for source populations for translocations. My results suggest that all populations may benefit from translocations to overcome genetic drift and inbreeding and to safeguard the historical genetic variation of the species.

The Reticulated Flatwoods Salamander, Ambystoma bishopi, is an inhabitant of longleaf pine forests in the southeastern United States. Historically distributed across southern Alabama, Georgia, and the Florida panhandle west of the Apalachicola-Flint Rivers, the range of this species has been drastically reduced. It is currently listed as federally endangered under the Endangered Species Act (ESA). Population viability analyses (PVAs) represent a key component of many recovery plans for threatened and endangered species. Here we use 10 years of mark recapture data collected from two breeding populations of A. bishopi to construct a demographic model that can be used to evaluate future extinction risk. In chapter one, we quantify population sizes through time, and estimate the impact of annual variability in numbers on genetic viability. This species exists in small (< 500) breeding populations and exhibit annual fluctuations in abundance characteristic of pond-breeding amphibians. In chapter 2, we adopt a modified version of the von Bertalanffy equation to construct size-at-age curves for A. bishopi that include the metamorphic transition. Individuals exhibit rapid growth in the larval stage such that they emerge as metamorphs at 60% of their final body size. In chapter 3, we employ a Cormack-Jolly-Seber model, modified to include continuous covariates, to generate size-dependent survival curves. Survival of A bishopi exhibits dramatic annual and seasonal variability, but is always positively correlated with body size. Lastly, in chapter 4, we combine the elements of all previous chapters to construct an Integral Projection Model (IPM). Given the prevalence of complete recruitment failure in these populations, and their relatively small size, extinction probabilities under a business-as-usual model were high. Increasing the frequency of successful recruitment drastically reduces extinction risk; however, adult survival exerts the greatest influence on long-term population growth. To assure the recovery of A. bishopi, management must consider all elements of the life-history when allocating resources and effort. More generally, both aquatic and terrestrial habitats must be protected for amphibian conservation to be effective, making them ideal candidates for 'umbrella species' status. Amphibian conservation would also benefit from an increase in systematic, long-term data collection. / Doctor of Philosophy / The southeastern United States is the global salamander hotspot, representing a crucible for diversity. Longleaf pine forests, the predominant ecosystem in the southeast, have been reduced to 3% of their former range, with dire consequences for the animals that inhabit them. The Reticulated Flatwoods Salamander, Ambystoma bishopi, is endemic to the region, and currently listed as federally endangered owing to recent population declines. A recovery plan for the species therefore, is required by law, under the Endangered Species Act (ESA). A salient component of modern recovery plans are population forecasts that evaluate future extinction risk. Such forecasts can then be used to assess alternative management strategies proposed to improve the species' long-term prospects. By studying two of the last remaining populations of A. bishopi from 2010-2019, we were able to collect the data required to construct a demographic model that can be used to run population projections. In some regards, A. bishopi is a typical amphibian, in that their populations show dramatic fluctuations in numbers through time, and they exhibit rapid growth in the aquatic larval stage, achieving 60% of their maximum body size in the first three months of life. Flatwoods salamanders breed in ephemeral wetlands, that often dry before successful metamorphosis can occur. The frequency of pond-drying results in a high probability of extinction for a single population, but survival of breeding individuals was equally important when considering long-term persistence. To assure the recovery of A. bishopi, management must consider all elements of the life-history when allocating resources and effort. More generally, both aquatic and terrestrial habitats must be protected for amphibian conservation to be effective, making them ideal candidates for 'umbrella species' status.

In recent years, critical habitat has been subject to a great deal of controversy and numerous lawsuits. Critical habitat is an integral part of the Endangered Species Act (ESA) that serves not only to protect the species and its habitat but may also help the recovery of the species. Critical habitat has been the subject of a large number of recent lawsuits. These lawsuits arise from conservation groups, forcing the Fish and Wildlife Service (FWS) to designate critical habitat and from developmental groups, claiming that the economic analyses used by the FWS during the designation of critical habitat are faulty. The economic analyses that are currently being done by the FWS are quantifying the costs of critical habitat to the extent possible while virtually making no effort to quantify the benefits of critical habitat. This potentially biased economic analysis can skew public opinion by presenting an unbalanced result from the analysis. Therefore, this thesis presents a methodology for comprehensively identifying and quantifying, where possible, the costs and benefits of critical habitat.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Univ., Diss.--Göttingen, 2005. / Literaturverz. S. 372 - 395.

abstract: Since its inception in 1973, the Endangered Species Act has been met with both praise and criticism. More than 40 years later, the Act is still polarizing, with proponents applauding its power to protect species and critics arguing against its perceived ineffectiveness and potential mismanagement. Recovery plans, which were required by the 1988 amendments to the Act, play an important role in organizing efforts to protect and recover species under the Act. In 1999, in an effort to evaluate the process, the Society for Conservation Biology commissioned an independent review of endangered species recovery planning. From these findings, the SCB made key recommendations for how management agencies could improve the recovery planning process, after which the Fish and Wildlife Service and the National Marine Fisheries Service redrafted their recovery planning guidelines. One important recommendation called for recovery plans to make threats a primary focus, including organizing and prioritizing recovery tasks for threat abatement. Here, I seek to determine the extent to which SCB recommendations were incorporated into these new guidelines, and if, in turn, the recommendations regarding threats manifested in recovery plans written under the new guidelines. I found that the guidelines successfully incorporated most SCB recommendations, except those that addressed monitoring. As a result, recent recovery plans have improved in their treatment of threats, but still fail to adequately incorporate threat monitoring. This failure suggests that developing clear guidelines for monitoring should be an important priority in future ESA recovery planning. / Dissertation/Thesis / M.S. Biology 2014

The U.S. Endangered Species Act (U.S. ESA) is one of the oldest pieces of legislation to protect endangered species. The bodies responsible for administering the U.S. ESA have published species Biennial Recovery Statuses (BRSs) in Reports to Congress on the Status of Endangered and Threatened Species. We found that expert assessments of species recovery trends match BRSs reasonably well; however, there appears to be a weak relationship between the BRSs and available data tracking species abundance and range trends. We aimed to establish whether the recovery trends of species examined were detectably associated with their threats, the general U.S. ESA tools, or recovery actions. We found positive associations between species recovery and two U.S. ESA tools – mean annual funding and peer-reviewed scientific information. However, correlations with other variables differ greatly depending on how recovery is defined. Species threats and recovery actions are also moderately related to their abundance and range trends.

The rate of extinction of plant and animal species has accelerated at an alarming rate throughout the 20th century. This depletion has resulted in greater legislative control over wildlife within the United States, and the eventual passage, in 1973, of the Endangered Species Act (ESA). The ESA establishes regulations designed to protect species which are threatened with extinction. The ESA has evolved out of past legal statutes and jurisprudence concerning the management and protection of wildlife, but the ESA has created controversy since inception. The latest criticisms concern its lack of success in meeting stated policy goals of preserving species richness and recovering listed species. As a result, a new movement has developed which seeks to change the traditional species-by-species approach of the ESA to an approach which concentrates on entire ecosystems. Ecosystem approach proponents sight various advantages, one of which is cost-effectiveness. This thesis analyzes the development of wildlife protection within the United States, and the Endangered Species Act in particular. The purpose of this analysis is to examine both the legislative powers granted for wildlife protection, and the feasibility of the ESA to encompass ecosystem protection. Modifications to the ESA are proposed. The Clinch River Valley, in Southwest Virginia and Northeast Tennessee, is used as a case study for a cost-effectiveness analysis of an ecosystem approach and species-by-species approach. Costs generated through Fish and Wildlife Service recovery plans are used in conjunction with generated ecosystem plan recovery costs. The results of the cost-effectiveness analysis show that an ecosystem approach is more cost-effective in meeting the recovery goals within the 0inch River Valley. The ESA can be modified to incorporate an ecosystem approach. Such modification can protect species richness and allow for a priority ranking system for protection. / M.S.

The antelope jackrabbit (Lepus alleni) inhabits the seasonal landscape of the subtropical Sonoran savanna grassland in southern Arizona. Basic ecological information on this understudied lagomorph is lacking beyond historical responses to rangeland conditions. This is the first study to utilize radio collars to assess space use of antelope jackrabbits. In the semidesert grassland of Buenos Aires National Wildlife Refuge, Arizona, we estimated antelope jackrabbit home range size, seasonal ranges, and movement patterns. Home range estimates were comparable to other Lepus species, however, seasonal range sizes did not differ. We analyzed antelope jackrabbit habitat structure, measured vegetation characteristics, and determined whether there was a spatial association between antelope jackrabbits and the endangered Pima pineapple cactus (Coryphantha scheeri var. robustispina). Antelope jackrabbits selected vegetation structure and characteristics similarly to available areas on the refuge. We did not detect a spatial association between antelope jackrabbits and Pima pineapple cacti, however given the importance of understanding endangered species relationships, further investigation is warranted. Our results add to the limited ecological information known about antelope jackrabbits and provide baseline data for future studies. Knowledge about spatial ecology and habitat selection helps managers and biologists make informed recommendations for land and wildlife management.

Modeling species of conservation concern, such as those that are rare, declining, or have a conservation designation (e.g. endangered or threatened), remains an activity filled with uncertainty. Species that are of conservation concern often are found infrequently, in small sample sizes and spatially fragmented distributions, thereby making accurate enumeration difficult and traditional statistical approaches often invalid. For example, there are numerous debates in the ecological literature regarding methodological choices in conservation-based models, such as how to measure functional traits to account for ecosystem function, the impact of including rare species in biological assessments and whether species-specific dispersal can be measured using distance based functions. This thesis attempts to address issues in methodological choices in conservation-based models in two ways. In the first section of the thesis, the impacts of methodological choices on conservation-based models are examined across a broad selection of available approaches, from: measuring functional diversity; to conducting bio-assessments in community ecology; to assessing dispersal in metapopulation analyses. It is the goal of this section to establish the potential for methodological choices to impact conservation-based models, regardless of the scale, study-system or species involved. In the second section of this thesis, the use of consensus methods is developed as a potential tool for reducing uncertainty with methodological choices in conservation-based models. Two separate applications of consensus methods are highlighted, including how consensus methods can reduce uncertainty from choosing a modeling type or to identify when methodological choices may be a problem.