Dissertations / Theses on the topic 'Wildlife conservation|Wildlife management|Natural resource management'

Interest in renewable energy and governmental mandates has motivated land managers to consider cellulosic feedstocks for bioenergy. I investigated plant community response to a system including switchgrass ( Panicum virgatum) as a feedstock intercropped with loblolly pine (Pinus taeda). I estimated plant species evenness, richness, and diversity and biomass production, with emphasis on white-tailed deer ( Odocoileus virginianus) forages. I detected 225 species in 2,220 1-m² quadrats, and 7,495 biomass samples (96.4 kg dry weight) from 960 quadrats. Intercropping reduced plant species diversity, total non-pine tree biomass, and biomass of deer forages during switchgrass establishment. These effects were no longer apparent at treatment level two years after switchgrass establishment, except that deer browse and total deer forage biomass remained less in intercropped interbeds. Intercropping in managed pines may temporarily effect plant communities but further studies are needed to examine longer term effects and to quantify effects on nutritional carrying capacity for deer.

Understanding survival and breeding season length of game birds are important for effective management and conservation. By determining the variables that drive survival and recovery rates for white-winged doves (Zenaida asiatica), I can offer management implications to agencies across their range. There is currently little knowledge about white-winged dove molting and hatching chronology. The objectives of this study were to: 1) investigate annual survival and recovery rates of white-winged doves, 2) determine intrinsic and extrinsic factors influencing them, 3) determine AHY primary feather molt rate and the factors that influence molt rate and initiation, and 4) describe hatch chronology and determine the factors that influence hatching. To understand what influences annual survival and recovery, I examined subpopulation, climate variables, urbanization characteristics, molt, and band type as covariates. I used the Brownie approach in the RMark package of R to compare annual survival and recovery models and generate estimates. I used Underhill and Zucchini models in the Moult package of R to determine AHY primary feather molt rate and the best predictors of molt rate and initiation. I analyzed molt scores of HY doves recorded during annual banding using GLMs in R to determine the factors that influence hatching. I used AIC to select the most parsimonious models for each a priori candidate set. I analyzed 71,675 bands, of which, 3,086 were recovered from 2007 – 2016. My most supported model influencing survival and recovery was [S(age class x urban intensity) f(age class X MRPP)]. Average AHY primary molt rate across Texas was 13.21 ± 0.93 days. MRPP subpopulation + Year was the most supported model influencing AHY primary molt rate, AHY molt initiation, and hatch date. Within my sample, 95% of AHY white-winged doves began molting from 7 April to 8 July and completed molt 17 August to 17 November. White-winged doves hatched as early as 6 January and as late as 27 July, with 95% of all hatching occurring between 22 March and 18 June and peaking at 5 May. Urban intensity was an important variable influencing annual survival, which is expected for such an urbanized species. MRPP subpopulations influenced vital rates and should be considered for future harvest management.

Reservoirs throughout the country exhibit degraded shorelines and simplified littoral habitats because of aging. This study evaluated the establishment of agricultural plantings on reservoir mudflats and the effectiveness of supplemental brush pile structures in providing recruitment habitat for juvenile fish. The mudflats of Enid Reservoir, Mississippi were seeded during the winter drawdown in October of 2016 and 2017 with agricultural plantings. Monitoring of plantings found grasses performed best in terms of establishment and providing potential fish habitat. During Summer 2017 brush piles and control sites, without brush, were sampled in Enid Reservoir using rotenone to evaluate juvenile fish use. Juvenile fish exhibited greater abundances and larger sizes, on average, in brush pile sites. Larger brush piles placed in shallower water provided the greatest benefit to juvenile fish.

Rice not collected by harvesters and natural seeds are important foods for waterfowl. Estimation of abundance of these seeds is necessary for calculating waterfowl habitat conservation needs in the Louisiana Chenier Plain (LCP) and Texas Mid-Coast (TMC). My objectives were to quantify dry mass of rice and other seeds from August-November 2010, and estimate waterbird abundances on farmed and idle ricelands in these regions from December 2010-March 2011. Rice abundance in farmed ricelands ranged from 159.7 kg/ha (CV = 66.6%) to 1,014.0 kg/ha (CV = 8.3%). Natural seed abundance in idle ricelands ranged from 99.7 kg/ha (CV = 32.9%) to 957.4 kg/ha (CV = 17.2%). Greatest waterbird densities occurred in shallowly flooded disked ricelands (mean = 7.35 waterbirds/ha, 90%; CI = 2.37-19.70). Ratoon, disked, and shallowly flooded ricelands are important habitat for non-breeding waterbirds but variable estimates of seed and waterbird abundances warrant continuation of this study.

The Galápagos Archipelago is recognized internationally as a unique eco-region, and many of the species that inhabit these islands can be found nowhere else on Earth. The Ecuadorian government recognized the value of this ecosystem, and, beginning in 1959, they designated 97% of the Archipelago as Ecuador's first National Park. The Charles Darwin Foundation also was founded in 1959 and, since then, the Park Service and the Foundation have worked towards preserving the Galápagos' unique flora and fauna for future generations. The waved albatross (Phoebastria irrorata) is the largest bird species found in the Galápagos Archipelago and was recognized as an iconic species early in the Park's history; it is the only tropical albatross. This species spends the majority of its life foraging at sea and is an important predator in the Humboldt Current off of the coast of South America. With the exception of a few pairs, this albatross breeds entirely on the southeastern most island of the archipelago, Española. Tourists visit Española every year to watch the elaborate courtship dances of this species, and albatrosses in general have been the foci of legends among sailors for centuries.

M.P. Harris (1969) began banding waved albatross as early as 1961, marking the beginning of a long-term monitoring program with a focus on estimating age-specific first-time breeding, abundance, and survival. This initial effort resulted in the first estimates of abundance and survival for the waved albatross (Harris 1973). Following these initial estimates, the population size of the waved albatross has been estimated in 1994 (Douglas 1998), 2001 (Anderson et al. 2002), and 2007 (Anderson et al. 2008). These estimates suggest that the population has been declining since 1994. Motivated by this apparent decline, Awkerman et al. (2006) investigated survival and concluded that survival estimates from 1999-2005 were lower than average survival from 1961-1970 (Harris 1973). Today, the waved albatross is considered critically endangered, with bycatch in artisanal longline fisheries and the increased occurrence of El Niño-Southern Oscillation events thought to be contributing to these observed declines in survival and abundance. Given these observed declines in the waved albatross, the importance of the species in the ecosystem, and its intrinsic value in terms of biodiversity, continued monitoring and analysis efforts are needed to evaluate trends over time, and to gauge the effectiveness of management actions. My thesis is focused on these topics.

In Chapter 1:, I describe a framework to estimate abundance of wildlife populations, apply this framework to estimate population size of the waved albatross at a major breeding colony on Española Island, and I conclude by providing recommendations for future island-wide surveys of this species.

In Chapter 2:, I revisit the dataset collected by M.P. Harris and the Galápagos National Park from 1961-1981 as well as a more recent dataset collected by K.P. Huyvaert and colleagues. I analyzed these datasets in a multistate mark-recapture framework to estimate and compare estimates of adult survival as well as other important demographic parameters that have not yet been evaluated for this species.

Bycatch from fisheries and extreme weather events have influenced survival and breeding probabilities of many pelagic seabird species worldwide. Lower adult survival of the waved albatross is thought to be associated with bycatch in the small-scale fishery located off of the coasts of Peru and Ecuador as well as with El Niño-Southern Oscillation events. Previous efforts to document these threats have not formally considered that a variable proportion of the population does not breed every year or that different life history stages may have different survival rates.

The results from Chapter 1 suggest a continued decline in the principal breeding population of the waved albatross since 1994, and Chapter 2 shows indirect evidence that this decline may be linked to higher mortality associated with recent documented increases in small-scale longline fishing effort off of the coast of South America. Outside of the Galapagos Marine Reserve where fishing is heavily regulated by the Galapagos National Park Service, little is done to directly manage artisanal fishing operations off of the coasts of Peru and Ecuador. Conservation initiatives recognizing the environmental impact of fishing in this zone have been promoting reduction of seabird bycatch by educating local fishermen. Despite these conservation efforts, the results from my thesis suggest a continued population decline for this critically endangered species and additional mitigation may be needed for the persistence of the waved albatross.

Historically, black bears occurred throughout Mississippi but by 1932, <12 bears remained. Repatriation in neighboring states and conservation efforts in Mississippi have led to the recolonization of at least 2 subspecies (U. a. luteolus and U. a. americanus) of black bears in the state. I compiled available data to provide a synthesis of the history, current status, and management of black bears in Mississippi. Additionally, I used global positioning data collected from radio collared bears to determine the influence of distance to source population, cover type, distance to roads, distance to water, wetland reserve program areas, and human population density on black bear resource selection at various spatial scales. I studied characteristics of space use and resource selection of recolonizing bears in the Mississippi Alluvial Valley (Delta). I assessed the influence of environmental parameters at the female core annual home-range (using 50% kernel density estimator) and male and female seasonal and annual home-ranges (95% kernel density estimator). Distance to source population and distance to roads had significant influence at the core female home-range scale. I found a sex-based difference in annual and seasonal home-ranges. I also found that bears exhibited response to and selection for specific resources with an affinity toward hardwood stands, particularly young-aged hardwoods. My research illustrates the importance of analyzing resource selection at multiple scales to gain a full understanding of parameters that influence the recolonization of a bear population.

Involving a diversity of stakeholders in conservation issues is an important and growing trend in wildlife management. My thesis provides a case study of a collaborative conservation effort in which representatives from sportsmen’s and environmental groups came together to advise the Arizona Game and Fish Department in a project to restore bighorn sheep to the Santa Catalina Mountains near Tucson, Arizona. These stakeholders formed the Catalina Bighorn Sheep Restoration Advisory Committee to help address the human dimension factors of the project, build public support, and guide project planning and implementation. In addition to participant observation and document analysis informing my study, I surveyed 31 stakeholders both on and off the Advisory Committee and interviewed key Advisory Committee members. All stakeholders were in favor of collaborative conservation. However, there were objections to this particular Advisory Committee for this particular project. Although stakeholders had a diversity of values that informed their beliefs, the Advisory Committee members who took the time to understand the science involved, develop mutual trust and respect for others at the table, and held a strong commitment to the project goals were able to shift deeply held, values-based beliefs and find consensus on contentious project elements. This included agreeing on a mountain lion management plan that called for the killing of mountain lions that preyed on the newly reintroduced bighorn sheep. Stakeholders not on the Advisory Committee did not come to agreement on most elements of the project. This study contributes to the understanding of collaborative conservation efforts by providing a case study of a controversial wildlife conservation project that involved diverse stakeholders who worked together, successfully found consensus, and achieved their main goal of getting bighorn sheep back on the mountain.

The road network in the U.S. is immense, and vehicle use has expanded to incredible proportions since the early 1900s. While the use of this network has proven useful to people, roads and vehicles cause severe environmental degradation. An important part of this degradation is direct mortality of wildlife due to road-kill, with some estimates of vertebrate fatalities reaching the hundreds of millions each year in the U.S. alone. Until the last few decades, little attention was given to the problem of road-kill. A few recent studies have conducted statistical and GIS analyses to identify and predict locations of road-kill in order to strategically implement mitigation strategies. These road-kill studies focused on few species and/or limited study areas.

In the U.S., suburban areas have been expanding in recent years, but have been largely absent from the research on road-kill. This study investigates road-kill of the small vertebrate community on the fringe of the St. Louis metropolitan area and identifies significant land use/land cover attributes surrounding road-kill and hotspot locations using logistic regression models and hotspot analyses. The findings clearly show that rates of road-kill in this area are substantial and worthy of mitigation. Locations were identified for reducing overall rates of road-kill, such as areas nearer to forest fragments and farther from cultivated lands that are surrounded by greater amounts of open and low intensity developed areas and lesser amounts of cultivated lands. If mitigation were targeted in locations identified in this study, it could lead to reductions of thousands of road-kills each year.

Interactions between animal populations and their environment form the foundation of wildlife management, and provision of resources that enhance fitness produce effectual management. Hunting is a selective force that shapes behavior and other adaptations of harvested species and may subsequently impact diel habitat use. Moreover, linking habitat use to biological outcomes, such as survival, is needed to evidence habitat suitability because of equivocal relations among population density, habitat correlations, or energy availability to population dynamics. The mallard (Anas platyrhynchos) is among the most coveted and harvested waterfowl in North America and is a migratory species of ecological, economic, and social importance. The Mississippi Alluvial Valley (MAV) is an ancestral and continentally important wintering area for North American mallards despite significant anthropogenic wetland transformation. Through targeted objectives and consequence of soil and water conservation, financial assistance programs have expanded waterfowl habitat on private lands in Mississippi. I radiomarked 265 female mallards and tracked their diel habitat use in winters 2010-2015 to evaluate objectives related to their wintering ecology in the MAV of Mississippi. Specifically, I investigated whether waterfowl hunting influenced use of some habitats during hunting season, the effectiveness of financial assistance programs in providing habitat, and habitat suitability through habitat specific survival rates. Females made greatest use of forested and emergent wetlands diurnally and emergent wetlands and flooded cropland at night. Results suggested that mallards did not avoid flooded cropland or emergent wetlands diurnally during hunting season, but conclusions were complicated by significant use of inviolate sanctuaries. Mallards used numerous incentivized conservation program wetlands, but use was less than public and privately managed wetlands. Among conservation programs, those with large enrollment and a focus on restoration (i.e., Wetlands Reserve Program) were most used by mallards. Apparent survival was independent of diurnal habitat use suggesting that mallards use of wetland complexes leads to their winter survival. Restoration of forested wetlands should be a management focus and easement programs provide such inroads on private lands. Public wetlands are an important source of habitat and inviolate sanctuary should be considered where waterfowl hunting is a predominate activity.

Feral pigs (Sus scrofa) are one of the most ecologically harmful species in North America and are expanding across the U.S. at alarming rates. Feral pigs are an extremely prolific, destructive species and native ecosystems will continue to suffer unless resource managers intervene to reduce the damages caused by feral pigs. In 2015, in cooperation with the Texas Parks and Wildlife Department–Kerr Wildlife Management Area, I investigated the efficacy of several novel feral pig control prototype products (i.e., toxic baits) to: 1) compare lethality and length of intoxication times between 13 microencapsulated sodium nitrite (MESN) formulations in pseudo gavage dosed captive feral pigs; 2) evaluate residual sodium nitrite levels and potential risks of vomited MESN bait on non-target species; and 3) assess the lethality of 5 unique sodium nitrite formulations in group pen feeding trials. Pseudo gavage trials resulted in 4 MESN formulations achieving a 100% lethality rate with delayed emergence of intoxication symptoms compared to previous literature. Unexpectedly, gastric coatings delayed the onset of intoxication to the same degree as enteric coatings. Vomit appeared to be positively correlated with the delivery of a lethal dose of MESN paste bait as 55/56 pigs (98.21%) vomited and died. Residual sodium nitrite in vomited bait was 90% less than the sodium nitrite concentrations in the delivered paste matrix. Despite this reduction, vomited bait could serve as a potential threat to non-target and secondary consumers, although the degradation time, residual persistence, and probability of non-target vomit consumption remains unknown. Group pen trials, testing 5 unique sodium nitrite formulations, resulted in ?80.95% overall lethality, with the greatest individual formulation lethality equaling 96.77%. Results from these studies will be beneficial in determining a MESN feral swine toxicant formulation for registration with the United States Environmental Protection Agency in the future.

In an effort to highlight best practices in the management of wild eastern brook trout, an examination was performed of brook trout management plans and stocking habits for seven randomly selected states within the species native range. Additionally, surveys were distributed to these state’s members of Trout Unlimited (TU) in an effort to understand angler motivations, awareness of and attitudes about their state’s stocking practices and protection of wild brook trout fisheries. The states selected were within the eastern brook trout’s native range and included West Virginia, Tennessee, Pennsylvania, Maine, Vermont, Maryland, and North Carolina. While each state differs in its efforts to either restore or protect existing wild brook trout populations, all seven states continue to stock hatchery-raised brook trout to maintain a viable sport fishery. However, regarding stocking dynamics, each state has unique policies regarding where the stocking occurs in relation to how these efforts potentially impacts wild populations. Survey results indicated that, while the majority of TU members expressed a strong understanding of their states stocking practices, they were still strongly interested in gaining additional information, indicating a need for more transparency regarding stocking habits and practices. Furthermore, survey results indicated that a large percentage of TU members still enjoy fishing for popular, nonnative, sport fish such as bass and brown trout. Additionally, support for policies protecting wild brook trout diminished as opportunities for catching larger fish diminished along with the removal of popular, nonnative sport fish. Overall, results indicated a need for fisheries managers to work more closely with cold-water conservation organizations, such as Trout Unlimited, and their members to assist in the crafting of policies that benefit both the sport fishing industry and wild brook trout populations.

Barren-ground caribou herds are part of social-ecological systems that are of critical importance to northern Indigenous Peoples of the Arctic, contributing to nutritional, cultural, and spiritual well being that are today undergoing significant changes. This dissertation uses multiple disciplinary lenses to understand the dynamics of these systems and to clarify methods for studying them. Chapter 1 focuses on a prediction of summer (June 1- August 31) mosquito activity and potential insect harassment of caribou in response to a changing climate. The Mosquito Activity Index (MAI) was based on daily ambient temperature and wind velocity obtained from the North American Regional Reanalysis dataset (NARR) from 1979 to 2009 for summer ranges of Alaska’s four Arctic herds: Western Arctic Herd (WAH), Teshekpuk Caribou Herd (TCH), Central Arctic Herd (CAH), and Porcupine Caribou Herd (PCH). Mean MAI was lowest for TCH, followed by WAH and PCH and highest for CAH. Over 31 years there was an increasing trend in MAI that affected the summer habitat of TCH and PCH, but a decreasing trend for WAH. Intra-annual patterns in MAI among herds differed in peak MAI. Chapter 2 presents a novel method of participatory videography to document the knowledge and experiences of Caribou People. Ninety-nine interviews were videoed in six arctic communities of North America in the summer of 2008 as part of the International Polar Year. Chapter 3 presents “Voices of Caribou People,” a composite film of those interviewed, portraying the range of topics reported. Chapter 4 presents the results of an open-coding content analysis of a sample of 34 of the Voices Project interviews. Interviews described people’s rich memories of the past, aspects of their traditional knowledge and practices, the changes they have observed, the challenges they face, and what they perceive as their needs to meet present and future challenges. A key finding of the analysis is that while the research community and funding agencies are highly focused on climate change, Caribou People expressed greater concern about their social, economic, and political challenges. Caribou people noted that more studies undertaken in full partnership with caribou user communities along with community authority in decision-making are needed to sustain their human-caribou systems.

Current scientific knowledge of the ringtail (Bassariscus astutus ) is limited, thus impeding appropriate management decisions. Ringtails in Zion National Park, Utah, are rarely seen, but are involved in increasing occurrences of negative interactions with park visitors and employees such as food theft and denning in buildings, interactions which are harmful to both parties. To manage this conflict, an update to the general knowledge about the status of the population is required as the only previous study on ringtails in this area was conducted in the 1960s. Using noninvasive techniques provides dependable large-scale population information. I used two noninvasive detection methods in combination to establish a robust occupancy estimate of the ringtail population in Zion National Park. Ringtails were detected in 2 of 3 focus areas in the park, but at low densities. This study included the development of a novel method to individually identify ringtails by their footprints. I used the Interactive Individual Identification System (I3S) software to determine if individuals could be identified using the pattern formed by papillae and ridges of the footpad. Ringtails' footpad prints consistently resulted in a unique pattern recognizable by simple visual analysis and a computer-aided analysis of the prints in a database; however more research is needed for the applicability using field data. Ringtail densities were highest in the areas of greatest human activity. The proximity to humans may be impacting ringtail diet and consequently their health. I collected scat in areas of high and low human use to quantify the change in diet resulting from food acquired around human establishments. Ringtails living in areas of high human activity exhibited a change in diet, including the presence of human trash such as foil and plastic; this has implications for ringtail health and human safety. Ringtails acquiring food from human sources may increase their activities around buildings and areas with high human activity, resulting in an increased chance of direct and indirect human-ringtail interactions. Active management of human activities and regular building maintenance is required in the future to decrease negative consequences of ringtail use and presence in areas of high human activity.

The Unimak Island caribou herd is in the midst of a population decline associated with low birth rates and calf survival. I evaluated the spatial and temporal complexity of caribou landscape use and the availability and nutritional quality of key forage species. First, I examined seasonal landscape use and movement using GPS collar data. Second, I determined seasonal diets to the species-level for spring, summer, and fall using a novel n-alkane and long-chain fatty acid (LCOH) method. Finally, I compared diet quality with needs for maintenance and to the quality of available plant species. Caribou home ranges were largest and movements least in the winter, and movements appeared dependent on plant phenology and weather conditions. Diets were complex and seasonally variable but generally contained higher proportions of forbs than other caribou herds likely due to their higher relative availability as compared to other preferred forages. Finally, animals foraged selectively each season, obtaining a diet that was higher in digestible dry matter and nitrogen than the average of plants available. Nutritional quality appeared to be well above requirements during the three seasons investigated. Overall, I concluded that spring, summer, and fall forage quality and availability do not impose strong constraints on Unimak Island caribou. However, I recommend that diet composition and quality be determined in the winter, the time when forage often limits the productivity of caribou herds.

Physical evidence of past fires, left in the form of cambial scars, suggests that low and moderate intensity fires have burned periodically for centuries in the coast redwood (Sequoia sempervirens) forest in California's central coast bioregion. These fires may have played an important role in shaping stand age structure and composition. Nonetheless, the ecological role of fire in shaping successional processes in the redwood ecosystem is not well understood. The extent to which both aboriginal and more recent burning practices have affected the central coast landscape is also uncertain. Standard dendrochronology techniques were used to reconstruct and analyze the fire history of the coast redwood forest in the Santa Cruz Mountains based on the fire scar record. Three hundred and seventy-three fire scars were identified in 70 cross-sections that were removed from redwood stumps, downed logs, and trees in select locations between Davenport and Año Nuevo, California. The earliest recorded fire occurred in 1352 and the most recent in 2009. The grand mean fire return interval (FRI) for single trees (point) was 60.6 years, and the median FRI was 40.1 years. Fire scars were found most frequently in the dormant and latewood portions of the annual growth rings, signifying that fires tended to occur in the late summer and fall. A high degree of variability in the data set suggests that cultural burning practices occurred on fluctuating temporal and spatial scales.