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 68 for “"ecotone"”.
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Remote sensing characterisation of the forest-tundra ecotone
… forest and Arctic tundra, the Forest-tundra ecotone (FTE), is an area of high ecological and climatological significance. Satellite remote sensing has the potential to enable accurate circumarctic mapping and characterisation of both latitudinal and altitudinal FTEs. This study aims at a …
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Pattern and process at a desert grassland-shrubland ecotone
… and process at a desert grassland-shrubland ecotone. First, small-scale species coexistence patterns in microsites around dominant grasses (B. eriopoda) and shrubs (L. tridentata) were compared. Second, small-scale patterns were related to landscape scale species richness. Third, a …
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Vegetation and Soil Patterns at a Mountain Wetland Ecotone
… bog meadows across the open meadow – bog forest ecotone. To determine the patterns of infilling and the potential relationships among the trees, microtopography, and soil conditions, I collected and analyzed data on each of these factors within nine belt transects located across the ecotone. I …
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Differential detoxification strategies in closely related herbivore species across a sharp ecotone
… lepida and N. bryanti live across a sharp ecotone in which they encounter plants with vastly different chemistry. Neotoma lepida, more of a specialist, prefers the cyanogenic glycoside-containing Prunus fasciculata, while N. bryanti, more of a generalist, has a more varied diet including a …
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Ecophysiology and Food Web Dynamics of Spring Ecotone Communities in the Edwards Aquifer, USA
Spring orifices serve as ecotones between groundwater and surface water habitats. It is thought that organisms living in physicochemically stable spring ecotones should exhibit small tolerance ranges; however, previous experiments examining this prediction are equivocal. I examined this hypothesis …
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Fine-Scale Mechanisms Influencing Germination Success, Seedling Growth and Survival in an Alpine Forest-Tundra Ecotone
… and seedling survival in the alpine treeline ecotone? Four specific investigations were used to answer these questions, each one addressing a key aspect of seed production, germination, and seedling growth: (1) Seed production, dispersal, and predation were quantified across the treeline …
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Assessing the influence of geological and land-use gradients on zooplankton and phytoplankton biodiversity in the land between ecotone
The Land Between (TLB) is an ecotone in south-central Ontario that represents a transition from limestone-dominated bedrock to granite-dominated bedrock, creating notable calcium and land-use gradients across this unique geographic region. The goal of this study was to investigate water quality and …
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Combined effects of warming and drying on a temperate-to-boreal forest ecotone exert additive changes on soil microbiome structure and diversity
… zones such as the temperate-to-boreal forest ecotones, which are poised to experience substantial changes under projected climate change over the next century and beyond. Because these systems are projected to move towards a warmer, drier climate, it is important to understand how the soil …
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Spatio-temporal distribution of grass and shrubs at the ecotone between an arid grassland and succulent shrubland : ecological interactions and the influence of soils
… ecological investigations of vegetation at an ecotone between the Namaqualand shrublands and Bushmanland arid grassland at the climatic transition between the predominantly winter rainfall Succulent Karoo and the predominantly summer rainfall Nama-Karoo biomess. The work focused on the …
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Analysis of red spruce (Picea rubens) regeneration in Pocahontas, Randolph, and Tucker counties, West Virginia
… to 11 years and by forest zones (i.e. hardwood, ecotone, red spruce zones). These communities experienced an increasing density of red spruce over time across all forest zones. Red spruce was successfully establishing and expanding across the ecotone into the hardwood forest zone. The greatest …
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Influence of fire and habitat on the removal of invasive plant seeds by granivores in longleaf pine savannas
… (hereafter “upland habitat”), and upland-wetland ecotone communities, which included P. palustris, Acer rubrum, Liriodendron tulipifera, shrubs, cane, and forbs (hereafter “ecotone habitat”). Over two 15-day periods, seeds were presented in depots that allowed either arthropod, or arthropod and …
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Holocene variations in summer temperature and effective moisture: Understanding the causes of vegetational dynamics in Alaska
… pools. However, responses of the forest—tundra ecotone to the modern warming trend are spatially heterogeneous because controls other than temperature limit tree growth and seedling establishment near tree line. Paleo-investigations can address the sensitivity of the forest—tundra ecotone to …
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THE SPATIAL CHARACTERISATION OF TRANSITIONAL AREAS BETWEEN PLANT COMMUNITIES: A CASE STUDY FROM UPLAND BRITAIN
The concept of the ecotone was formalised by Clements (1 905) as a boundary zone between plant communities. Little research exists on the ecological importance or the geographical variability of these zones. Two types of boundaries are acknowledged: the ecotone and the ecocline. The ecotone is a …
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Geographic variation in the echolocation calls of the endemic Cape horseshoe bat, Rhinolophus capensis (Chiroptera: Rhinolophidae)
… biome; Steenkampskraal and Table Farm were ecotone populations situated in the western and eastern limits of the distribution, respectively. Interspecific analysis revealed that the two ecotone populations deviated slightly from the allometric relationship between body size and peak …
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Assessing changes in pollen assemblage and charcoal accumulation during known changes in climate from c. 5,400 to 3,300 Years Before Present at the forest-prairie ecotone in Alberta, Canada
The ecotone between aspen parkland and mixed-grass prairie in mid-eastern Alberta is a climatically-sensitive area that has been subject to periods of enhanced aridity occurring at multi-decadal to centennial-scale cycles throughout much of the last 6000 years. To assess the ecotonal response to …
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VEGETATIVE REPRODUCTION BY LAYERING VERSUS SEXUAL REPRODUCTION IN A SPRUCE-FIR FOREST AT ALPINE TREELINE, MEDICINE BOW MOUNTAINS, USA
… tree islands found across the alpine treeline ecotone. Observational data on vertical stem origin, size, and cone production were collected for fifty krummholz mats and forty tree islands within the Libby Flats area. Vertical woody stems originated mainly from layering in both the krummholz …
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Landscape-Scale Variability in the Composition, Growth and Pattern of Alpine Treeline Vegetation
… warming, particularly across the treeline ecotone. However, responses to warming in the past century have been highly variable, especially in regions with complex topography. In order to improve predictions of future change, I used field surveys, dendrochronology, and remote sensing to …
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Distribution Patterns and Taxonomy of Freshwater Ascomycetes Along the Florida Peninsula
… differs along the temperate-subtropical ecotone of the Florida peninsula. Ordination analysis shows that pH might also be an important factor in the distribution patterns of freshwater ascomycetes in Florida. Results from the ordination analysis indicated that community composition is not …
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