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.
Results
Showing 1 to 20 of 80 for “"exotic species"”.
-
Exotic Species of Hydrogen
… H3 and the negative ion of Hydrogen H-. These 'exotic' systems of Hydrogen are known to have a rather instable character due to their strong internal coupling and correlation phenomena. Their astrophysical significance and their role as exemplary cases in fundamental research justify the great …
-
Exotic Species Invasion and Biodiversity in Bangladesh Forest Ecosystems
Both, biological invasion by exotic plant species and biodiversity including spatial patterns and drivers are two major issues in tropical forest ecosystems. This dissertation deals with these two issues in a tropical forest ecosystem in Bangladesh. Considering the first issue, it comprises two …
-
Transforming an Exotic Species: Nineteenth-Century Narratives About Introduction of Carp in America
… known today as one of America's most infamous exotic species, was among dozens of fishes stocked in new waters within the United States during 1870-1900, as part of a general enthusiasm for plant and animal acclimatization. Even before the U.S. Fish Commission [USFC] imported its first breeders …
-
Resistance to Three Common Herbicides in Chameleon Plant (Houttuynia Cordata Thunb.), a Highly Invasive Exotic Species
… been much research on H. cordata as a medicinal species, and its potential as an invasive species is well documented. However, its herbicidal resistance has not previously been quantified. The objective of this study is to assess H. cordata’s resistance to herbicides. This study consisted of two …
-
The Role of Native Diversity and Successional Processes on Communityinvasibility in Riparian Primary Forest
… (~100ha) and address the following: 1) Does exotic species richness and percent cover change across successional time? 2) What is the relationship between native and non-native diversity and does that relationship change through succession? Vegetation surveys were conducted to quantify plant …
-
Vegetation colonization within exposed reservoirs following dam removal on the Elwha River, Washington
… In each plot , I recorded vascular plant species composition and woody species height. I collected and pooled 8 soil samples (20 cm) / plot to assess percent organic matter, nutrients, and percent sand, silt, clay, and conducted a Wolman Pebble Count. I used a structural equation models to …
-
Thresholds for sustainable regeneration in urban restoration plantings in Hamilton City, New Zealand
… to a drier and warmer climate, a prevalence of exotic seed sources and isolation from remnant native forest seed sources. This research investigates how these factors influence native species presence in different aged urban forest patches and uses life history traits to identify vulnerable …
-
Effects of Barriers on Migratory Bull Trout and Application of a Conceptual Framework to Evaluate Tradeoffs Associated with Dam Removal in the Clearwater River Drainage, Montana
… but can also be beneficial by preventing exotic species expansion. Therefore, evaluation of these tradeoffs is critical before making decisions that may affect the long term viability of populations. The disruption of movement corridors due to damming and interactions with nonnative …
-
Effects of Barriers on Migratory Bull Trout and Application of a Conceptual Framework to Evaluate Tradeoffs Associated with Dam Removal in the Clearwater River Drainage, Montana
… but can also be beneficial by preventing exotic species expansion. Therefore, evaluation of these tradeoffs is critical before making decisions that may affect the long term viability of populations. The disruption of movement corridors due to damming and interactions with nonnative …
-
Pollination in a changing world: function and resilience
… intensification by collecting pollinator species from flowering fields along an agricultural gradient. I also quantified functional redundancy (species with similar functional roles) by measuring pollinator functional traits. I measured (2) changes to pollination services with agricultural …
-
Determinants of native and exotic plant species diversity and composition in remnant oak savannas on southeastern Vancouver Island
… can influence the distribution of native and exotic species in ecological communities. I examined the regional- and local-scale determinants of native and exotic vascular plant species richness and composition in a highly fragmented oak savanna ecosystem on southeastern Vancouver Island. In …
-
The impacts of seven silvicultural alternatives on vascular plant community composition, structure, and diversity in the southern Appalachians
… plant community were characterized by changes in species diversity, species composition, exotic species richness, Raunkiaer's life-forms, and growth-forms. Pre-treatment, baseline data, and a randomized block design ensured the precision of post-treatment comparisons. High-disturbance treatments …
-
Assessing risk to native ecosystems: using exotic ants as a model
Invasive species are widely recognised as drivers of ecological change. As such, understanding the processes that facilitate invasion success, and the potential mechanisms and magnitude of impact, are critical for effective biosecurity management. Predicting risk associated with exotic species, so …
-
Vegetation Survey of the Yegua Knobbs Preserve, Bastrop and Lee Counties, Texas
… and the Blackland Prairies to the west, merge. A species inventory was done to identify the vascular plants present at the preserve for a growing season. Woody vegetation was sampled using the line intercept method, and herbaceous components were sampled using the quadrat method. Analysis of the …
-
Beaver (Castor Canadensis) Impacts on Herbaceous and Woody Vegetation in Southeastern Georgia
… aggressive colonizing plants, notably non-native species, to invade and potentially dominate. This study examined if beavers in southeastern Georgia have an effect on the terrestrial plant community. Sampling areas included beaver modified (N=9) and nearby but relatively non-impacted riparian …
-
Processes determining plant species diversity in restored tallgrass prairie
… found that across many restorations, invasion by exotic plants was the best predictor of outcomes, significantly reducing beta-, and site-level plant diversity. We also found that seeding more species reduced exotic species to increase diversity. Mowing also tended to increase diversity. We …
-
Host plant associations and chemical ecology of Cerambycidae
Invasive species are a major threat to forest ecosystems, threatening native biodiversity, forest health, altering nutrient cycles, and deteriorating water and soil qualities. In the United States alone, economic losses are estimated to be around $120 billion, both from impact of invasive species …
-
The colonisation of fynbos and disturbed sites by indigenous forest communities in the Southern Cape
… Furthermore, large areas are infested with exotic species such as Acacia melanoxylon ·(blackwood), A. mearnsii (black wattle) and different Eugalyptus and Pinus species. Although these species are useful timber and firewood species, they tend to establish themselves on disturbed patches in …
-
Understanding Invasive Species Impacts on Reclaimed Surface-Mined Lands
… umbellata) is one of the most prevalent invasive species on reclaimed mines in Appalachia and viewed as one of the main hindrances to the successful reclamation of mined land to restore native forests. In order to better assess the impact autumn olive can have on reclamation success, we …
-
Investigation into the potential invasiveness of the exotic Narrow-leaved Bittercress, (Cardamine impatiens L.), Brassicaceae
Exotic species often invade new areas and displace native species. The problems associated with such invasions are well known, but for many exotic species, experimental work has not yet been done to predict which, and under what conditions they may become a problem. Two greenhouse experiments were …
Page 1 of 4