<p> Early detection of an invasive species facilitates control and eradication. Slender false brome <i>(Brachypodium sylvaticum)</i> was first discovered in the Santa Cruz Mountains of Central California in 2003 as a non-native grass in redwood forests, competing with native vegetation. The current infestation in the Santa Cruz Mountains, estimated to be 300 acres, is concentrated in San Mateo County and could be eradicated. This study sought to determine most likely locations of slender false brome in the Santa Cruz Mountains by assessing environmental attributes of known presence locations using species distribution modeling and Maxent software. The study used 1,320 species presence points collected in field surveys conducted from 2009 to 2012, GIS environmental layers covering a 940 km² study area, and the machine-learning program Maxent to identify slender false brome habitat at a 30 m resolution in the Santa Cruz Mountains. Maxent models successfully identified locations of potential distribution of slender false brome (training AUC = 0.961, test AUC = 0.960). Annual precipitation, average annual maximum or minimum temperature, and soils were the most important predictors. An independent dataset corroborated the performance of the Maxent model. Maxent could be used by land managers for targeting field surveys by predicting most likely <i> B. sylvaticum</i> habitat in the Santa Cruz Mountains.</p>

<p>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.

<p> West Texas, especially the Trans-Pecos region, mainly consists of desert shrubs and grasslands with patches of higher elevation (1,500 &ndash; 2,000 m) mountain ranges. Black bears (<i>Ursus americanus</i>) were extirpated from this area by the 1940s because of predator control and over hunting. In the 1980s, black bears returned to west Texas in a natural recolonization movement from Mexico, where they had survived. The black bear populations of the Trans-Pecos region and northern Mexico fit a mainland-island metapopulation model. Based on previously published research on this recolonization event, I identified several likely habitat recolonization sites and corridor routes for use in predicting possible black bear dispersal throughout the area. Then, using these corridor and recolonization scenarios, I produced a black bear metapopulation model for the Trans-Pecos region.</p><p> The possible habitat recolonization site map was created by combining 2 habitat suitability index (HSI) maps and using these HSI maps to define 'core' and 'useable' black bear habitat within the Trans-Pecos region. Using these locations, along with dispersal probabilities and black bear demographic parameters, I created a corridor dispersal map of the area using the program Circuitscape.</p><p> The metapopulation model was created using STELLA modeling software. Each recolonization location in the Trans-Pecos region (Big Bend National Park, Black Gap Wildlife Management Area, and the Davis Mountains) has its own black bear subpopulation. The metapopulation model is a stochastic compartment model based on a yearly time step (&Delta;<i>t</i> = 1 yr). This model was tested for the effects of: carrying capacity per site, immigration rates from Mexico, rates of dispersal from Black Gap Wildlife Management Area to the Davis Mountains, and the recovery time for the area after complete extirpation from the Trans-Pecos. This information will help local biologists conserve and manage these returning black bears in the Trans-Pecos region. </p>

<p>I investigated percent coverage, plant height, species richness, and woody stem density in plant communities in ten study plots during spring and fall (2010&ndash;2012) within 3 different treatments (continual mowings, one fall mowing, and one fall mowing with native wildflower seeds) on Highway 25 right-of-way in Oktibbeha and Winston counties, Mississippi. I recorded 277 plant species including native and non-native forbs, legumes, grasses, rushes/sedges, and woody plants. Non-native agronomic grasses exhibited greatest coverage greater than 90 percent occurring in all treatments. Percent coverage of plants less than 0.46m height category exceeded 100 while, greater than 0.46m plant height categories averaged 55 percent. Woody stem density ranged from 7,772 year 1 to 10,025 stems/hectare year 2. I detected no significant differences in plant height or woody stems among treatments. One mowing per year retained agronomic plant cover for erosion control and annual cost savings up to 75 percent for roadside maintenance. </p>

<p> During the 1970s to the 1990s, Steller sea lions (<i>Eumetopias jubatus</i>) in Alaska declined severely, resulting in the western stock's listing as endangered under the United States Endangered Species Act. The localized depletion of their main food source around rookeries and haul out sites was the primary cause of their depletion. The western stock has still not recovered to historical levels. Therefore, scientists have continued to study Steller sea lions diet and foraging habits. One approach has been through stable isotope analysis of their various tissues. Analysis of their vibrissae, or whiskers, provides an exact record of an individual's diet from birth to the present. However, scientists so far have only measured stable isotope values of a single vibrissa from an individual, assuming no significant difference among vibrissae within or between cheeks. They have not accounted for the possibility of variable stable isotope accumulation in an individual's different vibrissae. In this study, I tested the assumption of no significant individual variability among vibrissae by examining the &delta;¹³C and &delta;¹⁵N values in all of the vibrissae on five Steller sea lion pups recovered in Alaska. &delta;¹⁵N values did not differ between vibrissae on a cheek or between vibrissae from left and right cheeks. The &delta;¹³C values did not differ between vibrissae within cheeks; however, &delta;¹³C values were significantly different between the left and right cheeks of Lowrie Island Pup and PWS 29 Pup. This between cheek variation is most likely due to small sample size rather than different stable isotope incorporation. The lack of &delta;¹⁵N value variation within or between cheeks, as well as the lack of &delta;¹³C variation within cheeks, supports the assumption that stable isotope accumulation is similar between all vibrissae and validates sampling protocols of previous studies collecting just the longest, thick vibrissa from a Steller sea lion. More studies similar to this one are needed to verify these findings and to look at variability in stable isotope incorporation of juvenile and adult Steller sea lion vibrissae as well as other mammal species.</p>

<p> Current scientific knowledge of the ringtail (<i>Bassariscus astutus </i>) 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.</p>

<p> The Gal&aacute;pagos 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 Gal&aacute;pagos' unique flora and fauna for future generations. The waved albatross (<i>Phoebastria irrorata</i>) is the largest bird species found in the Gal&aacute;pagos 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, Espa&ntilde;ola. Tourists visit Espa&ntilde;ola 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. </p><p> 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 Ni&ntilde;o-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. </p><p> 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 Espa&ntilde;ola Island, and I conclude by providing recommendations for future island-wide surveys of this species. </p><p> In Chapter 2:, I revisit the dataset collected by M.P. Harris and the Gal&aacute;pagos 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. </p><p> 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 Ni&ntilde;o-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. </p><p> 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.</p>

<p> The Brownsberg Nature Park (BNP) in Suriname is home to eight monkey species: <i>Saguinus midas, Saimiri sciureus, Cebus apella, Alouatta seniculus. Pithecia pithecia, Cebus olivaceus, Chiropotes satanas (sagulatus), </i>and <i>Ateles paniscus.</i> Several studies have undertaken the task to better study the feeding and behavioral ecology of these species within the park. However, studies on the black spider monkey (<i>Ateles paniscus</i>) have been absent. As part of my thesis, I decided to conduct a baseline feeding and behavioral ecology study of this species during the period May 2008 &ndash; July 2008. In addition, I developed a field method for determining mercury levels (in parts per million = ppm) in fecal and urine samples of wild monkeys. Since the park is under enormous pressure from illegal gold mining activities, I decided to collect baseline data on potential exposure of wild monkeys to mercury in the environment. I also collected samples from monkeys at the zoo in Paramaribo and monkeys born in captivity at Hiram College in Ohio. I collected data on the frequency of feeding, resting, and traveling by black spider monkey subgroups every 10 minutes during all day follows. Feeding ecology data consisted of identifying fruits eaten by these subgroups. For the mercury analysis I used the OSUMEX LTD. home testing kit. Results from the behavioral data show the following frequencies of activities for the entire study period: 32% feeding, 43% resting, and 25% traveling. The feeding data further justifies spider monkeys as ripe fruit frugivores: 76% of food items consisted of ripe fruit, while 22% consisted of leaves, and 2% was comprised of flowers. The mercury testing results from the Brownsberg and zoo populations ranged between 0.025 ppm to 0.1 ppm (toxic level = 0.8 ppm). The Hiram College monkeys all displayed levels at 0.000 ppm. The results from the mercury analyses indicate that 1) wild monkeys in the vicinity of gold mining activities may not be under the same threat as humans, with regards to mercury exposure through food, and 2) that wild monkeys are still relative exposed to mercury in the environment whether it be natural or anthropogenic.</p>

<p> 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.</p>