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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Activity pattern and diet composition of Formosan macaques ( Macaca cyclopis ) at Mt. Longevity, Taiwan

Wang, Ching-ping 20 June 2005 (has links)
Abstract The present study investigated the activity patterns of Formosan macaques at Mt. Longevity and an emphasis was given to feeding and foraging behavior. The diet composition of Formosan macaque showed significant changes among different age and sex classes of macaques as well as among different seasons. The field research was carried out from August 2003 to July 2004 for a total of 311 hrs covering 77 days. Feeding behavior dominated the activity patterns of the macaques at Mt. Longevity (28.11%), followed by other behaviors such as affiliate (24.71%), resting (17.10%) and moving (16.04%). In contrast, foraging (8.22%) and agonistic behaviors (5.50%) were the least among the activity patterns recorded during this study. Interestingly, adult males spent more time in resting (30.60%) while adult females spent more time in feeding (29.84%), which indicated that the activity patterns were influenced by sex and age groups. Plant food items accounted for 94.87% of their diet while the seminal fluid and breast milk accounted for 5.08%. The plant food items consumed by the monkeys came from 46 species in 31 families and the fruits alone amounted 42.18%. Other food items included leaf (26.20%), stem (11.84%), flower (10.33%), bud (9.14%) and root (0.03%). The relative frequency of fruit consumption by the macaques was higher than 40 % between May and September (40.53% - 63.79%) and December to January (54.66% - 55.28%). The Formosan macaque diet composition changed according to the sex and age class groups. The Simpson index, Shannon-Wiener index and Levine¡¦s niche breadth index changed according to sex, age and months respectively. The plant food diversity indexes were highest for the juvenile males and lowest for the adult females. The Levine¡¦s niche breadth index was broader for the juvenile females but narrowest for the adult females. Adult females consumed 35 species of plants which is higher than the number of species that the adult males and juveniles consumed. However, the plant food diversity index and the niche breadth index were low for adult females, which indicate that they choose certain types of food. On the other hand, all these three indexes were highest in May and changed from month to month. The diet overlap of the Formosan macaque (Renkonen percentage) was highest between adult males and adult females (85.2%) than between other sex/age groups. Among the five categories of age and sex groups, the diet overlap was 66.68% and 22 species of plants was consumed by all age and sex groups of Formosan macaques.
2

Diet composition as a candidate mechanism underlying the depression-to-obesity association: the CARDIA study

Vrany, Elizabeth A. January 2018 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / People with depression are at elevated risk for future obesity; however, little is known about the potential mechanistic role of diet composition in this association. The aims of the present study were: (1) to examine depressive symptom severity as a predictor of 13-year change in seven diet composition factors over time, (2) to test 13-year change in diet composition factors as mediators of the association between depressive symptom severity and 13-year change in adiposity, and (3) to explore whether the Aim 2 mediation models are moderated by sex and race. Participants were 2,449 non-Hispanic Black and White adults who participated in the 1990, 1992, and 2005 years of the CARDIA study (mean baseline age = 35 years, 54% women, 56% non-Hispanic Black, mean baseline waist circumference = 84.0 cm, mean change in waist circumference = 8.3 cm). Depressive symptoms were assessed in 1990 using the Center for Epidemiologic Studies-Depression Scale (CES-D). Waist circumference and seven diet composition factors were assessed in 1992 and 2005. Diet composition factors included intake of total energy, saturated fatty acid, monounsaturated fatty acid, polyunsaturated fatty acid, fiber, sugar, and protein. PROCESS bootstrapping analyses were used to test for mediation and moderated mediation (see Figure 1 for the conceptual model). All models included adjustment for age; sex; race; education; prevalent and incident cardiovascular disease, diabetes, and cancer; incident pregnancy; and 13-year change in physical activity. Greater baseline CES-D Total predicted greater 13-year increases in waist circumference (path c β = 0.032, p = .006). In separate models, there was a trend for greater baseline depressive symptoms predicting 13-year increases in total energy intake (path a β = 0.040, p = .054), and greater baseline depressive symptoms predicted 13-year increases in protein intake (path a β = 0.059, p = .004) and fiber intake (path a β = 0.040, p = .0496). Depressive symptoms were unrelated to 13-year changes in intake of the other diet composition factors of saturated fatty acid, monounsaturated fatty acid, polyunsaturated fatty acid, and sugar (all ps ≥ .129). Mediation models revealed that 13-year change in total energy intake and protein intake partially mediated the association between baseline depressive symptoms and 13-year change in waist circumference (total energy intake indirect effect = 0.001, 95% CI=0.0001-0.004; protein intake indirect effect = 0.002, 95% CI=0.0004-0.005); mediation was not observed for the other diet composition factors. Exploratory moderated mediation models detected a significant interaction for CES-D Total by sex predicting 13-year change protein intake only (Index of moderated mediation=0.004, 95%CI=0.001-0.010). All other tests of moderated mediation were non-significant (95% CIs included zero). Analyses stratified by sex revealed that CES-D Total was more strongly associated with 13-year increases protein intake in men (β = 0.011, p=.004) than in women (β = 0.027, p = .246). Findings from this larger, longitudinal, epidemiologic study suggest that the prospective relationship between depression and future obesity risk may be explained, in part, by intake of certain diet composition factors. Advancing the understanding of the relationship between depression and diet changes will inform clinical efforts to prevent or manage depression-related obesity.
3

Assessment of the Response of Piscivorous Sportfishes to the Establishment of Gizzard Shad in Claytor Lake, Virginia

Bonds, Charles Craig 20 April 2000 (has links)
Gizzard shad were illegally introduced to Claytor Lake in the late 1980s and soon established a thriving population. This study assessed 1) the degree to which gizzard shad were utilized by piscivores (pelagic - striped bass Morone saxatilis, hybrid striped bass M. chrysops x M. saxatilis, and walleye Stizostedion vitreum, and three littoral black basses Micropterus spp.), 2) the availability of gizzard shad as potential prey as determined from age and growth analysis, and 3) the performance (growth rates, relative weight, and relative abundance) of piscivores before versus after gizzard shad establishment. Gizzard shad were more highly utilized by pelagic predators (especially striped bass and their hybrids) than black basses. Rapid growth of gizzard shad (mean back-calculated length at age-1 = 155 mm TL) meant that almost all morphologically available shad were age-0. The reliance on one edible age class of gizzard shad resulted in an unstable food supply as evidenced by much greater striped bass shad consumption in Summer 1998 (63 % by weight) when age-0 shad were more abundant than in Summer 1997 (7 % by weight). Striped bass was the only species to exhibit faster growth rates and mean relative weight (Wr) values in the 1990s versus pre-shad years. Walleye (except age-1) and black bass growth rates declined, and mean Wr values either remained consistent or declined. Largemouth bass and walleye were the only sportfish to show increases in relative abundance. Benefits of gizzard shad as a forage fish appear to be limited to striped bass and its hybrid species. It is possible that gizzard shad have had, directly or indirectly, an adverse impact on the black basses of Claytor Lake, but explanatory analysis of these relationships was beyond the scope of this study. / Master of Science
4

EFFECTS OF ABIOTIC AND BIOTIC FACTORS ON DIET COMPOSITION OF AGE-0 STURGEON (<italic>SCAPHIRHYNCHUS</italic> SPP.) IN THE MIDDLE MISSISSIPPI RIVER

Sechler, Dawn Renee 01 May 2010 (has links)
Due to habitat degradation and overharvest (Colombo et al. 2007) sturgeon populations are declining throughout their global distribution (Pikitch et al. 2005). In North America, five sturgeon species are listed as endangered or threatened due to overharvest and habitat degradation. One species of direct concern is the pallid sturgeon (Scaphirhynchus albus ) (Boreman 1997). The morphologically similar shovelnose sturgeon (S. platorynchus) is not listed as endangered but has become a cause for concern due to poor reproductive success and declining recruitment of their offspring to the adult population, likely a result of lack of proper spawning habitat and early life foraging opportunities (Wildhaber et al. 2007). Despite listing the pallid sturgeon as endangered and increasing concern about population decline, little information is available about the foraging ecology of age–0 Scaphirhynchus sturgeon. To ensure these sturgeon populations persist in the Middle Mississippi River, a better understanding of sturgeon foraging success during early life is imperative. I quantified age–0 Scaphirhynchus sturgeon (total length (TL) range: 14–200 mm; small < 50 mm TL, large 50–200 mm TL) diets during 2004–2008 to determine whether foraging behavior changed as a function of stage height, water temperature, water velocity, size class of sturgeon, and macrohabitat. I also examined whether energy density (cal/g) and selection of prey varied across size class and macrohabitat. Age–0 Scaphirhynchus sturgeon were collected from the Middle Mississippi River during spring (March, April, May), summer (June, July, August), and fall (September, October, November). Each prey item in diets was identified to family and measured to calculate dry weight. Ephemeroptera, Diptera pupae, and Chironomidae were the dominant taxa that were consumed across all years and seasons. Large sturgeon had a broader diet, consuming more non–dominant taxa. Abiotic factors differed across macrohabitats and thus influenced foraging behavior. Sturgeon occupying the island upstream tip (IUT) macrohabitat had the largest mean mass in diet and those at the island downstream tip (IDT) had the lowest mean mass in diet. Conversely, energy density of sturgeon was highest at IDT and lowest at IUT. Small sturgeon avoided macroinvertebrates that were outside the dominant prey taxa whereas large sturgeon selected for Chironomidae across all macrohabitats. Diets of age–0 Scaphirhynchus sturgeon vary as a function of size and are influenced by interacting of abiotic and biotic factors at each macrohabitat. As age–0 Scaphirhynchus sturgeon grow, their diet broadens. Diet of young sturgeon interacts with energy condition in counterintuitive ways that requires more study. Because foraging success differs among habitats and is likely linked to recruitment, habitat quality and quantity in the Middle Mississippi River is likely critical for sturgeon population density and growth.
5

Trophic interactions between larval gizzard shad and resident zooplanktivores in Claytor Lake, Virginia

Small, Ron 09 October 2002 (has links)
Anglers unlawfully introduced gizzard shad Dorosoma cepedianum into Claytor Lake, Virginia in the late 1980s, apparently with the intention of improving the sportfishery by adding an additional clupeid prey resource. This study examined the trophic interactions between larval shad and resident zooplanktivorous fishes, in an attempt to discover the potential for trophic competition and negative impacts to these fish species. Ichthyoplankton sampling in 1997 and 1998 showed that peak abundances of larval shad overlapped temporally and spatially with both larval Lepomis spp. and larval alewife Alosa pseudoharengus. Peak larval shad density (0.04-0.06 fish/m3) was two to three orders of magnitude less than that reported from other reservoir systems, slightly less than that of larval alewife in Claytor Lake (0.05-0.07 fish/m3), and significantly less than that of larval Lepomis spp. in Claytor Lake (0.28-0.51 fish/m3). Diet overlap values indicated potential resource overlap among all three larval taxa. Diet of larval shad did not overlap with that of either age-0 Micropterus spp. or adult alewife. All species of limnetic larvae examined showed feeding preferences for Diaphanosoma and copepod nauplii. Crustacean zooplankton densities did not respond negatively to peak larval fish abundances, and never dropped below 250-400 organisms/L. In Claytor Lake, the impact of trophic competition with larval gizzard shad on other zooplanktivores currently appears to be minimized by low densities of larval shad and abundant crustacean zooplankton. / Master of Science
6

Hnízdní úspěšnost a potravní ekologie puštíka obecného (\kur{Strix aluco}) / Diet and reproduction of the Tawny Owl (\kur{Strix aluco})

LUKA, Václav January 2011 (has links)
This Master thesis deals with diet of the Tawny Owl (Strix aluco) and reproductive parameters. Muridae rodents dominated diet composition and Arvicolidae rodents and birds were alternative preys. Clutch size positively correlated with proportion of rodents in diet.
7

Management, Foraging Behavior, Diet Composition and Forage Quality of Free-Ranging But Herded Camels in Ceeldheer District, Central Somalia

Elmi, Ahmed A. 01 May 1989 (has links)
In Somalia, camel (Camelus dromedarius) survivability and milk production has been higher than for other domestic livestock and contributes substantially to the subsistence of Somali pastoralists. The objective of this research was to study management, foraging behavior and nutrition of camels in their natural habitat to determine how production continues under seasonal nutritional stress. Management systems of Ceeldheer pastoralists are based on available natural pasture and water. The natural rotation grazing system maintained an ecological equilibrium in the District. Pastoralists manipulate their herds to suit existing environmental conditions, family needs and labor availability for herding. In herd management, control of breeding males and preferential treatment to increase the female component of the herd are geared to secure continuous milk supply for the family. Camels were watered only in the dry seasons. They foraged continuously throughout the day the first few days after watering, but foraged mostly in the morning and evening as watering days approached. The quantity of water camels consumed in summer and winter dry seasons were similar. In winter, milking camels foraged more, travelled shorter distance and rested less than dry ones. In fall, 1986, and spring, 1987, lactating camels spent less time foraging than non-milking animals. Foraging time was the same for both groups in summer 1986, 1987 and fall, 1987. Camels spent more time chewing bones in summer of 1986 in Xarar foraging area than other seasons. Low or high relative humidity together with hot temperature apparently reduced foraging time, increased rumination and idling times in winter and spring seasons. As forage availability declined, camels ingested a broader array of dietary items in the dry seasons and consumed large amounts of herbaceous plants. The diets of milking and dry camels were similar. Lactating camels consumed more green forage than dry camels in the dry seasons. Shrubs and trees comprised major components of the diets (80.9%). Physical structures of plant species did not prevent feeding on the plants. Camel diets were rich in crude protein (cp), calcium (Ca), potassiuim and sodium. Phosphorus (P) was deficient. Ca:P ratios were extremely low. Neutral detergent fiber and acid detergent lignin were high. CP intake seemed adequate year round assuming camel protein requirements are similar to other livestock requirements. Digestible energy was deficient in dry seasons. Low energy intake, inadequate phosphorous availability and water deprivation were probably responsible for the weight loss of camels as the dry season progressed.
8

Nest-Site Selection of Golden Eagles and Ferruginous Hawks and Diet Composition of Sensitive Raptor Species Using Metabarcoding Analysis in the Uinta Basin and Ashley National Forest, UT, USA

Hopkins, Dylan J. 01 August 2019 (has links)
Development and climate change in the sagebrush habitats are causing population declines of North American hawks and eagles. For these species, understanding the landscape features that are preferred for nesting and the prey they consume in sagebrush habitats are important in developing conservation plans. Specifically, we know little of the preferred nest-sites and diet of Ferruginous Hawks (Buteo regalis) and Golden Eagles (Aquila chrysaetos) many locales. In our study, we determined the landscape characteristics associated with nest sites for these two raptor species in the Uintah Basin, UT to predict where nests may occur in our study area. We found that slope, elevation, distance to nearest oil and gas wells, geology, and facing south were the most important variables in characterizing Golden Eagle nest-sites. Elevation, slope, vegetation type, and distance to nearest oil and gas wells were the most important variables in characterizing Ferruginous Hawk nest-sites. In addition, we looked at the diets of Golden Eagles, Ferruginous Hawks, and Northern Goshawks in the Uinta Basin, UT using a genetic analysis method novel to raptors. We found species consistent with previous diet studies and detected prey items not previously reported, including the Western Whiptail (Aspidocelis tigris), Domestic Cow (Bos Taurus), Domestic Pig (Sus scrofa), and Rock Bass (Amboplites rupestris) within Ferruginous Hawk samples. Results from our study can provide managers with tools to better survey for nest-sites and to provide an alternative method of diet analysis to provide insight into prey species important to these raptors.
9

A Bear's Eye View: Insight on American Black Bear (Ursus americanus) Hibernation and Foraging Ecology in Virginia's Central Appalachian Mountains

Holcombe, Brogan Elizabeth 07 June 2024 (has links)
Following mass agricultural expansion and deforestation in the late 1800s and early 1900s, American black bear populations (Ursus americanus, hereafter black bear) were low across most of Virginia. The Department of Wildlife Resources (VADWR) and the United States Forest Service worked to rebuild wildlife habitat in the state, leading to recovery of bears. While some aspects of black bear hibernation and foraging ecology have been studied, there remain knowledge gaps on key aspects of black bear biology. Hibernation behavior, for example, is understudied with most knowledge stemming from post-hibernation emergence studies. We used a unique dataset with continuous monitoring of mother bears and their cubs from Virginia Tech's Black Bear Research Center in 2015-2016, to better understand hibernation ecology, mother-cub dynamics, and biological-foster cub dynamics. We found that increased black bear activity levels were driven by both higher temperature and photoperiod, but the onset of hibernation was primarily driven by only temperature. Temperature is projected to rise in VA and rising temperatures regionally could be responsible for increased active behaviors in bears, which could lead to increased human-black bear interactions on the landscape, especially during hibernation onset. We also found that mother bears spend similar amounts of time with biological and foster cubs. Biological cubs did not show more dominance behaviors toward fosters than biological siblings, which we also observed with foster, where they did not continuously display these behaviors towards biological cubs. These results are promising for orphan cub fostering programs in VA and other states and indicate that foster cub litter integration can be successful. Foraging ecology also is challenging to study in black bears because direct observation is generally not possible due to their cryptic nature, closed habitat, or potential danger in observing. We used a dataset from camera collars deployed on 15 bears (8 males, 7 females) in Bath County Virginia in 2018 and 2019 to better understand diet seasonality and to determine habitat and environmental drivers of black bear foraging patterns, particularly on white-tailed deer (Odocoileus virginianus) and invasive plant species. We identified 178 unique diet items to family, genus, or species in videos, much higher numbers than previously reported in the literature, and we found high diet overlap between sexes. Diet composition was primarily influenced by season with higher levels of consumption of herbaceous soft mast in spring, fruit and seed soft mast in summer, and hard mast in fall. Females exhibited more hunting events on deer fawns in spring than males, but males and females consumed similar numbers (28 vs. 24, respectively) via hunting and scavenging combined. Males consumed anthropogenic foods more often than females, particularly when closer to human settlements and males more commonly consumed invasive plant species in spring while females more often consumed insect in spring invasive species in summer. Our results highlight strong seasonally- and subtle sex-mediated differences in black bear diets. We provide information on drivers of diet choices by bears, as well as identify where foraging hotspots on species of interest occur, providing information useful to VADWR in managing increased human-wildlife interactions (and mitigating potential for negative interactions), predator-prey relations, and invasive species spread across the landscape. / Master of Science / American black bears were almost eliminated from Virginia following mass agricultural expansion and deforestation in the late 1800s and early 1900s. The Department of Wildlife Resources (VADWR) and the United States Forest Service worked to rebuild wildlife habitat in the state, leading to recent recovery of bears in VA. However, there are still gaps in our knowledge of black bear ecology and gaining new knowledge will aid in better management of black bears across the state. We used two unique video data sets to study hibernation and foraging (or feeding) ecology to fill important knowledge gaps. To study hibernation behavior, we used a video data set of continuously monitored, temporarily captive mother bears and their cubs held at Virginia Tech's Black Bear Research Center in 2015-2016. We found that black bear activity was driven by both daily temperature and photoperiod (length of daylight), but onset of hibernation was mostly driven by temperature only. With Virginia projected to experience rising, and more variable, temperatures due to climate change, this may mean that bears will stay longer on the landscape in fall, even past the point where vegetation (food) has gone dormant, potentially leading to increased human-black bear interactions as bears seek human foods. We also examined mother-cub interactions and found mother bears did not spend more time with their biological cubs than their fosters (fosters are orphaned black bear cubs arising due to death of mothers) and biological cubs did not show more dominance behaviors (i.e., biting, chasing, or pinning to ground) toward fosters than biological siblings. These are positive results for VADWR's surrogate sow program across the state. Foraging ecology is difficult to study in black bears because direct observation is generally not possible due to their secretive nature, dense habitat, or potential danger in observing. Therefore, traditionally, many studies collect and examine scat (fecal) samples or stomach contents from harvested bears, but these methods may not find diet items that are quickly digested. We used a unique dataset from video camera collars placed on 15 bears in Bath County Virginia in 2018 and 2019. We found some important differences from the literature - our spring diets had higher proportions of deer and soft vegetation (leaves), however the unknown diet items in the literature were high, leading to incomplete or incorrect diet profiles. Diet composition was primarily influenced by season with higher levels of consumption of leafy soft mast in spring, fruit and seed soft mast in summer, and hard mast in fall. Males and females had high dietary overlap and we found that females had more hunting events on deer fawns in spring than males, but overall males and females consumed similar numbers (28 vs. 24, respectively) via hunting and scavenging combined. Males more often consumed human foods than females, while females more often consumed insect species than males. Also, males more commonly consumed invasive species in spring, while females did so in summer. Our results highlight differences in diet content caused by season and subtle differences in diets between sexes. We provide information on drivers of feeding choices bears make and we identify foraging hotspots for deer and invasive species, information useful to VADWR in managing potential human-wildlife interactions, predator-prey relations, and invasive species spread across the landscape.
10

Antipredační chování, pohlavní výběr a reprodukční úspěch u vrabce domácího (Passer domesticus) / Antipredatory behaviour, sexual selection and reproductive success in domestic sparrow (Passer domesticus).

Klvaňová, Alena January 2011 (has links)
Anti-predator behaviour, sexual selection and reproductive success in the House Sparrow Passer domesticus Alena Klvaňová Summary of the thesis Individual components of parental care are disproportionally distributed among the parents in the House Sparrow. While the female broods the nestlings more often and feeds them more frequently, the male defends the nest more intensely. In an experimental study the parents did not adjust their nest defence intensity to behaviour of their partners, nor to brood parameters. Only males tended to defend the sooner broods more intensely, which is in concordance with the "brood value hypothesis". Male contribution to nestling feeding affected their body mass. Male nest defence intensity increased with the size of their melanin ornament. Thus, we assume that the ornament could signal male investment in this component of parental care, while it does not correlate with feeding frequency and time spent by incubation. This output is probably caused by pleiotropic effect of genes regulating melanogenesis, affecting e. g. testosterone plasma level, which is associated with increased agression and lower intensity of other components of parental care as nestling provisioning or incubation. We have also aked the question whether the anti-predator strategy in House Sparrow is stable...

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