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A revision of the genus Sphaeralcea (Malvaceae) for the state of UtahJefferies, Jane Ardis Murray 01 August 1972 (has links)
It is the attempt of the present writer to present a concise picture of the genus Sphaeralcea as it occurs in the state. Descriptions, a specific key, distribution maps, illustrations and pertinent synonomy are presented.
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Wildflower establishment on landfills in central and southwestern VirginiaSabre, Mara 30 December 2008 (has links)
Municipal solid waste landfills are convenient means of disposing of society's waste; once closed, they become a liability to the community due to attributes which contribute to soil and water contamination. Regulations state that adequate vegetation be used to maintain the integrity of the soil trash cover. Alternatives to leaving a landfill derelict include establishing meadow-type communities that enrich floristic diversity while providing adequate cover to protect the soil cap over the trash.
In 1993, an experimental study was conducted at the Roanoke Regional Landfill where a mixture of native wildflowers and grasses and the standard revegetation mixture were sown on plots on varying aspects at the landfill. In 1993, the plots sown with the native mixture had a higher average species richness than the plots planted with the native mixture. Plots with the standard revegetation mixture had higher cover than plots planted with the native mixture.
In 1993 and 1994, an observational study was conducted at the Chancellorsville landfill in Spotsylvania county. Wildflowers had been seeded on part of the landfill in 1992. It was observed that the wildflower mixture decreased in species richness. The areas revegetated with the standard revegetation mixture had high richness due to the presence of invasive plants. Average cover over time was higher in areas planted with the standard revegetation mixture. Without regulations quantifying standards for aboveground cover, other methods should be implemented to determine to what extent revegetation mixtures are maintaining the integrity of a soil cap. / Master of Science
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Studies on the preservation of flowersElliott, Jennifer January 2002 (has links)
A known method for the preservation of green foliage was adapted in order to preserve floral tissues, retaining the colour and texture, thereby providing a method suitable for the preservation of whole flowers. Initially, the effects of the existing foliage preservation process on floral tissues were studied and the resulting problems of limp sticky petals and colour loss were identified. Subsequently, with a knowledge of basic plant anatomy and of the properties of the main floral pigments, the anthocyanins, a series of experiments on petals and whole flowers were carried out in an attempt to rectify these problems and to incorporate the remedies into a method for preserving whole flowers. The problem of improving the texture and firmness of flower heads was tackled by investigating the effects of adding bulking or setting ingredients to the process fluid and establishing their optimum concentrations. In the case of flower colour, the addition of acid was required in order to maintain the bright anthocyanin colours and a range of acids was investigated. Furthermore, since it is known that in nature the anthocyanin pigments are stabilised by metal ions and copigments, the use of these agents in the preservation process was also considered. This empirical work was then validated by confirming the identity of the main pigments involved and by studying various aspects of the new preservation process. Factors examined included acid concentration, temperature, solvent composition and the addition of metal ions and copigments to solutions of petal extracts containing anthocyanin pigments. Physical changes resulting from processing, including process fluid content and the moisture absorption properties of processed petals were also measured. Finally, the application of a selection of coating materials was assessed in an attempt to increase the life span of the processed flowers by providing extra protection against environmental stresses.
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Modelling population dynamics of Leysera gnaphalodes in Namaqualand, South AfricaConradie, Jessica Kate. January 2003 (has links)
Thesis (M.S.)--University of Pretoria, 2003. / Title from PDF t.p. (viewed Apr. 30, 2006). Includes bibliographical references.
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Consequences of habitat fragmentation for the pollination of wildflowers in moist upland grasslands of KwaZulu-Natal.Field, Louise Fabienne. 11 December 2013 (has links)
Large areas of moist upland grassland in KwaZulu-Natal are severely fragmented
due to large scale farming of exotic trees. The aims of this thesis were to
determine whether habitat fragmentation of these grasslands has a detrimental
effect on plant-pollinator interactions and hence the reproductive output of the
wildflower species occurring there and whether the magnitude of this effect can be predicted by breeding and pollination system characteristics.
The 24 wildflower species included in this study appear to support a rich
and diverse pollinator community, including long-tongued solitary bees, long-tongued
flies, hawkmoths and sunbirds. Two thirds of the wildflower species
appear relatively specialised in terms of pollination, with six species entirely
dependent either on a single species or a specific functional type of pollinator for
pollination. The majority of wildflower species (90%) were found to be incapable
of autonomous self-pollination and thus dependent on pollinators for fruit and
seed set. At least six species are obligately xenogamous. Little evidence was
found for pollen limitation in undisturbed moist upland grassland, suggesting that
these grasslands are characterised by high levels of pollinator activity. Greater
levels of pollen limitation of reproductive output in habitat fragments was
evident in two species, suggesting that depressed reproductive output in habitat
fragments may be the consequence of a decrease in the quantity and/or quality of pollinator services.
Significant detrimental effects of habitat fragmentation on reproductive
output were evident in two thirds of the wildflower species, with 94% of the
species exhibiting overall declines in seed set per flower from the continuous
grassland site to the habitat fragments. The median decline in seed set per
flower for the wildflower species was found to be 33.0%. Significantly more
species experienced overall declines in reproductive output than would have been
expected by chance alone. Only specificity of the pollination interaction in terms
of number of pollinator taxa involved was found to be significantly related to
percentage change in seed set from continuous to fragment habitats. This effect
was diminished when other factors were included in a multiple regression.
Results support Bond's (1994) hypothesis that degree of specificity in pollination
systems is important in determining extinction risk of a given plant species.
Declines in reproductive output of a range of wildflower species in grassland
habitat fragments may affect the local persistence of these populations,
particularly if recruitment is seed-limited. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2002.
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Investigating the most favourable seed establishment methods for restoring sand plain fynbos on old fieldsCowell, Carly Ruth January 2013 (has links)
Thesis submitted in fulfilment of the requirements for the degree
Master of Technology: Horticulture
in the Faculty of Applied Sciences
at the Cape Peninsula University of Technology, 2013 / Cape Flats Sand Fynbos (CFSF) is one of the most poorly conserved vegetation types in
the Cape Floral Kingdom, and a large proportion of unconserved land is degraded,
primarily as a result of transformation by agricultural, urban developments and invasion by
alien plants. Fynbos restoration is one of the most important management interventions,
both within the current conservation areas and in any future land remnants acquired for
conservation. Many extant remnants are fragmented and isolated, and if successful
restoration protocols are found, it may be possible to improve the conservation targets for
this critically endangered vegetation type. On old fields, where indigenous soil seed banks
have been lost due to alien plant invasion and anthropogenic action, it is essential to reintroduce
the longer-lived fynbos components that contribute to vegetation structure, in
order to facilitate the progress of the ecosystem on a more natural trajectory.
This research is built on an earlier study of optimal ground-preparation treatments for
restoring Sand Fynbos to old fields. This former study indicated that fossorial mammals
(molerats and gerbils) may occur in dense colonies on old fields and present an obstacle
to successful seedling establishment. The project aims to provide protocols for the
establishment of indigenous seedlings from harvested seed onto old fields, in order to
restore Sand Fynbos vegetation. Different pre-sowing treatments and sowing techniques
were tested on large field plots to determine the most efficient protocol. The objectives of
the research were: a) to investigate optimal pre-sowing treatments of indigenous seed for
restoring degraded Sand Fynbos vegetation in old field sites; b) to investigate optimal
sowing techniques on large field plots for restoring degraded Sand Fynbos vegetation in
old field sites with depleted indigenous seed banks; c) to provide guidelines and
disseminate information on optimal sowing protocols, and their costs, for restoring Sand
Fynbos vegetation in degraded areas and old fields. A further component of the research
was to calculate the costs of all treatments on a per hectare basis in order to assess the
cost-effectiveness of the different options.
Several different seed treatments may potentially increase the germination rate and
promote fynbos restoration. These are scarifying, smoke, smoke water, chemical, light and
temperature pre-sowing treatments. In order to keep the number of treatments (including
their interactions) to a manageable level, only soaking in smoke water extract and seed
coat scarification with course sand and grit were tested. A seed sample of each species
was x-rayed at the Millennium Seed Bank in the United Kingdom, to test for viability in the
seed samples, 52 % of the seed collected were empty, a typical indication of wild
harvested seed. All species were germinated at 10/25 °C and 16/8 hours light/dark
respectively. Scarification had a larger overall germination success, smoke water had very
little effect on CFSF species, it is rather that germination is related to temperatures during
a fire that result in seed coat splitting. It was recommended that further investigation using
more species across the Sand Fynbos vegetation be conducted on pre-germination
effects of heat and scarification.
The study site had been cleared of woody invasive alien vegetation and additional site
preparation included the application of a systemic herbicide to kill undesirable herbaceous
weeds, prescribed fire to clear the site of woody debris and destroy weed seeds, and the
local control of fossorial mammals (gerbils and molerats) by placing raptor perches and
owl nesting boxes around the site. This research found that the use of herbicide shortly
after the prescribed fire and once again prior to sowing was successful in controlling
herbaceous weeds and the indigenous grass Cynodon dactylon. The challenge to using
prescribed burning on old fields was low fuel loads, which resulted in a cool patchy. It is
suggested that cutting and spreading of alien plant biomass is tested as a solution,
however, the material must be evenly spread across the site and not stacked into piles
which can cause excessively hot fires and scorching of the soil. In order to better
understand soil conditions across the site, soil samples were collected prior to sowing, to
analyse for soil macronutrients, organic matter and pH. It was established that all the
excess nutrients added to the site from agriculture and pasturage over the years had
leached from the soil. However, the organic matter content of the soil was extremely low
and research needs to be done on the organic carbon content of the soils, how these
relate to soil micro biota (which species are present and their relationship with CFSF
species) and how best to enrich the site with humic matter for restoration and
establishment of Cape Flats Sand Fynbos. The field trial was set up in the Blaauwberg
Nature Reserve, a random split-plot block design, was replicated five times and used to
investigate the selected seedbed preparation and sowing techniques, namely: broadcast
sowing onto unprepared seedbed, broadcast with plank embedding of seed onto disked
seedbed, broadcast onto disked seedbed and hydro-seed with disked seedbed. Results
from the research found that the most successful methods for sowing seeds were the
hydro-seeding and broadcast with plank embed. These methods may have provided
better contact between the soil and seeds and better protection from predation and wind.
Economically the broadcast and embed was better as machinery was more efficient and
effective than manual labour. This study recommended that these two methods be
combined with the additional planting of rare and threatened species in clumps to
determine the benefits and interactions of each technique over the long term.
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A floristic and phytogeographic study of Glacial Mountain and vicinity, northwestern British ColumbiaDonovan, Laurance S. January 1987 (has links)
Botanical exploration in northern British Columbia has lagged behind that of adjacent Alaska and the Yukon Territories. This is particularly true of alpine and sub-alpine areas. For the most part, limited accessibility has restricted plant collecting to within a short distance of the few available roadways.
During the course of the present study, botanical field work was conducted in an alpine, sub-alpine area in the Three Sisters Range of the Cassiar Mountains (northwestern British Columbia). Over 1000 vascular plant collections were idenified from the study area. A total of 239 Taxa were recognized representing 116 genera and 44 families.
Taxonomic keys to the local flora and an annotated species list are provided. The annotated species list includes : habitat information for each taxon, a list of associated species and, where applicable, a discussion of noteworthy features of the taxon in question. Approximately 13% of the flora examined is listed as rare in British Columbia in Straley et al. (1985).
Virtually all of northern British Columbia was overridden by the Cordilleran Ice Sheet during the last major Wisconsin advance (approximately 22,000-15,000 yrs. b.p.). Potential Refugia from which taxa now present in the study area may have migrated post-glacially are discussed. Worldwide distributions of each taxon were examined and seven phytogeographic elements are recognized in the flora. / Science, Faculty of / Botany, Department of / Graduate
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The effect of burning frequency on invertebrate and indigenous flowering forb diversity in a Drakensberg grassland ecosystem.Arnott, Wendy Lynn. January 2006 (has links)
The KwaZulu-Natal Drakensberg, South Africa, is predominantly a grassland ecosystem maintained by fire. The effect of the current burning regime on invertebrate and flowering forb diversity in this ecosystem is poorly understood. The overall aim ofthis study was to contribute towards the development of an effective burning regime for the KwaZulu-Natal Drakensberg that will conserve invertebrates and indigenous forbs, two major components of biodiversity. The objectives were to examine the effect of fire and fire frequency on flowering forb and invertebrate species diversity, to determine whether fire frequency, time since last burn or locality were influencing species composition, and to identify potential biodiversity indicators that reflect overall species richness for use in monitoring of invertebrates and forbs. Sampling took place in March, September and November of 2002 at Giants Castle Game Reserve. Invertebrates were sampled using sweep netting and targeted netting along transects, yellow pan traps and soil quadrats. Invertebrate taxa sampled were ants (Formicidae), butterflies (Lepidoptera), grasshoppers (Orthoptera), leafboppers (Cicadellidae), bees (Apoidea), bee flies (Bombyliidae), hover flies (Syrphidae), robber flies (Asilidae), spiders (Araneae), earthworms (Oligochaeta) and millipedes (Diploda). These were identified to species level with the assistance of taxon experts. Flowering forbs were sampled using five replicates of five by five metre quadrats randomly placed in each site. Overall flowering forb and invertebrate species diversity was higher in grasslands that were burnt for two consecutive years in 2001 and 2002 than in grasslands that were not burnt during those two years. Frequently (annual) and intermediately (biennial) burnt grasslands had significantly higher invertebrate and flowering forb diversity than infrequently (five years without burning) burnt grasslands. This, together with the fact that grasslands burnt during the year of sampling had higher species richness than grasslands burnt two and five years previously suggests that invertebrates and forbs are generally resilient to fire and many forb species appear to be stimulated by fire. However, each burn frequency had its own suite of unique flowering forb and invertebrate species. Invertebrate communities were influenced mostly by locality and the length of time past since the last fire and flowering forb communities were influenced mostly by the length oftime past since the last fire. Fire frequency had the least influence on both invertebrate and forb communities. Ecological succession occurred after each fire in the invertebrate communities but forb communities appear to need more than five years without fire for ecological succession to occur. The findings of this study therefore suggest that using a combination of three fire frequencies would result in patches of grassland in various stages of ecological succession, and would conserve species unique to each burning frequency, and would therefore conserve maximum diversity. Flowering forb species richness and certain invertebrate taxa (ants, leafboppers, spiders and bees) have the potential to act as indicators of overall invertebrate species richness for use in monitoring programmes. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.
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