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 17 of 17 for “"niche separation"”.
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Co-occurrence and phenological niche separation in rodent pollinated Proteaceae
Despite the numerous studies regarding rodent pollination in the Cape Floristic Region in the last few decades, little or no work has been done on patterns of co-occurrence and flowering phenology. The presence of three potentially rodent-pollinated Protea species at Fernkloof Nature Reserve, two …
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Co-existence and niche separation of two subspecies of Photorhabdus temperata associated with Heterorhabditis downesi in a dune grassland
Entomopathogenic nematodes belonging to the families Heterorhabditidae and Steinernematidae form symbiotic relationships with entomopathogenic bacteria from the genera Photorhabdus and Xenorhabdus, respectively. Previous studies showed that Heterorhabditis downesi was associated with two different …
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Dietary ecology and niche separation among three closely related species (Parapapio jonesi, Pp. whitei and Pp. broomi) of South African Plio-Pleistocene Cercopithecoidea from Makapansgat Limeworks site
… research explores the possibility of dietary niche separation within this sample. Stable isotope (13C/12C, 180/160 ) and trace-element (Sr, Ba, Ca) techniques for palaeodietary analysis are employed to investigate papionin dietary ecology, and especially to search for evidence of subtle niche …
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Niche differentiation in savannas : exploring competition-based hypotheses for inter-life form coexistence
… possible if trees and grasses occupy different niches when exploiting limited resources such as water and nutrients. I investigated two competition-based models, each of them considering a different axis for niche separation: the two-layer hypothesis, which is based on differences in rooting …
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Competition and Phenology of Invasive and Native Grasses in the Northern Great Plains
… was to investigate two attributes (phenological niche separation and competitive ability) that may contribute to the invasiveness of smooth brome and Kentucky bluegrass. The objectives of my thesis were to: (1) determine if phenological niche separation exists between invasive and native species; …
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Rivalry for nutrient resources : is there competition below ground between leguminous trees and grasses in a mesic and arid savanna in the Kruger National Park?
… different down the soil profile. Therefore, the niche-separation hypothesis was not supported. The Scheiter & Higgins (2007) model illustrates that even though rooting niche separation is not an essential precondition for grass-tree coexistence, competition in the rooting zone can shape patterns …
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Plasticity and partitioning of foraging behaviour among and within sympatric Pygocelis penguin populations
… often have overlapping foraging ranges and niches that may lead to competition. Interspecific (between species) and intraspecific (within species) competition are important processes that may shape the foraging behaviours of penguins. However, competition pressure may vary with changes in …
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Comparative ecology of the copepods calanoides carinatus and calanus agulhensis in the Southern Benguela and Agulhas Bank ecosystems
The aim of this study was to investigate the niche separation between these two species, using zooplankton net samples collected during biannual hydroacoustic surveys of pelagic fish between 1988 and 2000, as well as results from ship- and laboratory-based egg production and feeding experiments. C. …
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Leaf nutrient draw back as a strategy for tree grass co-existence in the savanna biome
… manage to coexist in the savanna biome, the niche separation by phenology hypothesis (Scholes and Archer 1997) was tested by observing the seasonal variation in carbon and nitrogen concentrations in leaves and young twigs of two deciduous species, Combretum apiculatum and Terminalia sericea. …
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Effects of Management Practices on Grassland Plant and Bird Community Composition in Kane County Forest Preserves
… environmental gradients which can be defined as niche separation. This study attempted to determine what environmental gradients had the strongest impact upon grassland bird and plant species niche separation, particularly those gradients defined by management activities such as burning, chemical …
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The lazy root : Will a change in the rainfall regime or increased anthropogenic nitrogen result in an alteration in the competitive balance between trees and grassed in a semi-arid South Africa savanna?
… savannas, Walter (1971) first proposed the root niche separation model for savannas which suggests that trees and grasses have differential access to water due to spatial differences in their rooting profiles. Subsequent studies in various savannas around the world have found that this is often …
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Habitat, distribution, and diet of the Tennessee Bottlebrush Crayfish (Barbicambarus simmonsi)
… a predator within the stream and there is some niche separation between them and other crayfish species.
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Coexistence and resource use in space and time in a West African tortoise beetle community
… explain community organization with a strict niche separation and specialization of the single species, achieved mainly by interspecific competition and consecutive resource partitioning. Recent non-equilibrium or stochastic models see stochastic factors ("intermediate disturbances") as more …
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Influence of soil water regime on nitrogen availability and plant competition in wet meadows
… nutrient concentrations indicated evidence of niche separation between species.
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Investigation of Factors Influencing Niche Differentiation of Ammonia-oxidizing Archaea and Bacteria in Freshwater Environments
… environmental factors that influence the niche differentiation of AOA and AOB from freshwater environments. In order to investigate factors that drive the diversity of freshwater AOB communities, we enriched AOB from lakes representing a range of trophic states. The resulting enrichments …
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Comparative Biology of Sympatric Red Diamond and Southern Pacific Rattlesnakes in Southern California
… within the context of resource use and niche partitioning. Using radio-telemetry and mark-recapture involving passive integrated transponders (PIT) tags, I studied Red Diamond (Crotalus ruber) and Southern Pacific (C. oreganus helleri) Rattlesnakes in Chino Hills State Park, California, …
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Ecological studies of isopoda and diplopoda in dune grassland
… Finally the results are discussed in relation to niche separation, iv life history strategies and the role of macrodecomposers in the dune grassland ecosystem.