Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"food limitation"”.
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Genotypic Differences and Life-History Trade-Offs in the Freshwater Zooplankton, Daphnia Pulicaria, Under Natural Levels of Food Limitation
… studied, few have examined the effect of low food concentrations on life history traits. Since Daphnia spp. are frequently subjected to periods food limitation caused by natural phytoplankton cycles, it is necessary to understand how individuals respond in low food environments in order to …
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Parent-Offspring Conflict and the Allocation of Parental Investment in the Feral Pigeon (Columba Livia) (Nestling Growth, Concorde Fallacy, Food Limitation)
… hypothesis was tested by giving a group of birds food mixed with pebbles which increased the adult birds' foraging time. Fathers did not feed offspring with playbacks more often than controls in the group with increased foraging costs. In a second group without pebbles, fathers fed offspring …
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Variability of copepod abundance and growth in the southern Benguela upwelling system and implications for the spawning of the Cape anchovy
… of the growth rates of copepods, the effect of food-limitation on fecundity and somatic growth outweighed that of temperature.
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Ecological Causes of Life History Variation Tested by Meta-analysis, Comparison, and Experimental Approaches
… of alternative ecological explanations (food limitation, nest predation, adult mortality) for life history variation to an among-species context and test these predictions using a comparative-experimental design across a broad range of bird species from three continents. I found resource …
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Ecological Causes of Life History Variation Tested by Meta-analysis, Comparison, and Experimental Approaches
… of alternative ecological explanations (food limitation, nest predation, adult mortality) for life history variation to an among-species context and test these predictions using a comparative-experimental design across a broad range of bird species from three continents. I found resource …
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Modeling Food Assemblage Dynamics in Western Mississippi Sound Regarding Eastern Oyster (Crassostrea virginica) Larval Performance
… Previous studies speculate upon the potential of food particle size as a food limitation for emerging larval cohorts resulting in limiting successful recruitment into the reefs (Klein et al. 2024a,b). Utilizing ambient salinity and temperatures outlined in Klein et al. (2024a), simulated food …
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Predatory Impact of Exotic Cladoceran Cercopagis pengoi on the Zooplankton of Lake Ontario
… I assessed the impact of Cercopagis on the lower food-web of Lake Ontario by analyzing the historical and seasonal abundance of the crustacean zooplankton, by conducting laboratory feeding experiments, and by estimating consumption demand of Cercopagis based on bioenergetic considerations. A …
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Life-history evolution and cooperative breeding in the sociable weaver
… has been attributed to hypotheses relating to food limitation, nest predation, and reduced seasonality leading to high adult survival. Still, to date few studies have investigated this issue. In particular, detailed studies from southern regions are scarce and as a result our understanding of …
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Habitat partitioning by sparrows along an elevational gradient
… account for species distributions including: food, predation, and habitat structure. These factors were unable to account for the distributions of sparrows wintering along an elevational gradient in the Sonoran Desert of southern California, USA. Sage sparrows (Amphispiza belli), …
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Determinants of predator abundance in northern KwaZulu-Natal: top-down or bottom-up?
… change is critical. Both bottom-up (e.g. food limitation, competition) and top-down (e.g. predation, interference) processes play an important role in structuring predator guilds, yet there is a poor understanding of their relative importance. Here, I investigated whether the relative …
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Reproductive limitation in coastal ospreys (Pandion haliaetus): an ecological and an evolutionary perspective
… determine: ( i) the proximate control that local food supply exerts on reproductive performance in these populations; (ii) how food limitation has ultimately shaped life-history patterns in this species, especially clutch-size and laying date. Reduced food delivery to nests increased nestling …
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The Effects of Limited Winter Food Availability on the Population Dynamics, Energy Reserves, and Feather Molt of the Swamp Sparrow
… zone winters posed by cold weather coupled with food scarcity. These challenges are often assumed to occur, but are rarely experimentally tested. I hypothesized that the naturally occurring, lower abundances of food in temperate zone winters limit a bird's ability to acquire optimal energy and …
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The roles of predation, competition, and exploitation in the community dynamics of the New River in West Virginia
… competition, and fishery exploitation in the food web of this large, warmwater stream. The fates of production of the harvested crayfish (Orconectes virilis, Orconectes sanbornii sanbornii, and Cambarus sciotensis), hellgrammite (Corydalus cornutus larvae), smallmouth bass (Micropterus …
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The Implications of the Target-Area Hypothesis on the Population Dynamics of the Spotted Spiny Lobster, <i>Panulirus guttatus</i>
… may be impacted by trade-offs with predation, food limitation and reproduction. In Chapter III, I explore the mating dynamics of <em>P. guttatus</em> as a function of different population size structure distributions that might occur on small and large patch reefs. Finally, in Chapter IV I …
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Foraging for a foothold: Causes and consequences of dietary variation in a threatened avian pollinator
… important for species that are threatened due to food limitation, as dietary variation could be used to inform conservation efforts. In this thesis, I used the hihi (Notiomystis cincta), a threatened New Zealand passerine, as a case study to explore the causes and consequences of dietary variation …
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THE ROLES OF FOOD AND PREDATION IN SHAPING ADAPTIVE AND MALADAPTIVE BEHAVIORS IN POSTFIRE BIRD SPECIES
… after a wildfire. I report on the importance of food limitation versus nest predation on the expression of plastic life-history traits in Dark-eyed Junco (Junco hyemalis). Junco clutch size was primarily determined by habitat-specific and seasonal changes in food availability, while nest …
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THE ROLES OF FOOD AND PREDATION IN SHAPING ADAPTIVE AND MALADAPTIVE BEHAVIORS IN POSTFIRE BIRD SPECIES
… after a wildfire. I report on the importance of food limitation versus nest predation on the expression of plastic life-history traits in Dark-eyed Junco (Junco hyemalis). Junco clutch size was primarily determined by habitat-specific and seasonal changes in food availability, while nest …
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An integrative approach to testing density effects in a migratory songbird, the Prothonotary Warbler (Protonotaria citrea)
… observations and I estimated their song, food search movement (i.e., hops, walks, and flights), and prey attack rates in relation to density. Male behaviors varied somewhat in relation to neighbor density, particularly during specific stages. Males with more neighbors sang at a greater …
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Movement ecology and habitat use of Canada geese using major metropolitan areas in the context of human-wildlife conflicts
… Winter is an energetically costly period due to food limitation and increased thermoregulatory costs. Urban areas have altered these dynamics and facilitate northward shifts in wintering distributions by providing anthropogenic food sources, reduced predations risk, and thermal refugia for many …
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The foraging ecology of banded mongooses (Mungos mungo): Epidemiological and human-wildlife conflict implications
… to see which factors, including nutritional limitation, predation risk, and reproduction (and associated competition, agonistic encounters, and predation), best explained the variation in glucocorticoid production among our study troops over several years. We found that the metrics …
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