Spelling suggestions: "subject:"islands"" "subject:"lslands""
461 |
Indigenous Knowledge on the Marshall Islands: a Case for Recognition JusticeGessas, Jeff 12 1900 (has links)
Recent decades have marked growing academic and scientific attention to the role of indigenous knowledge in climate change adaptation, mitigation, and detection strategies. However, how indigenous knowledge is incorporated is a point of contention between self-identifying indigenous groups and existing institutions which combat climate change. In this thesis, I argue that the full inclusion of indigenous knowledge is deterred by certain aspects of modernity. In order to overcome the problems of modernity, I argue that a recognition theory of justice is needed as it regards to indigenous knowledge. Recognition justice calls for indigenous groups to retain meaningful control over how and when their indigenous knowledge is shared. To supplement this, I use the Marshall Islands as a case study. The Marshall Islands afford a nice particular case because of their longstanding colonial relationship with the United States and the impending danger they face of rising sea levels. Despite this danger, the Republic of the Marshall Islands calls for increased recognition as leaders in addressing climate change.
|
462 |
Acclimation effects on thermal tolerance in ameronothrid mites at sub-Antarctic Marion IslandDeere, Jacques Andries 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: Evidence for widespread ecological impacts due to rapid climate change is on the
increase, with further warming predicted over the next century. This increase in warming
has lead to organisms adjusting their distribution range and where this is not possible
organisms must cope with the stressful environments in a different way. One potential way
to handle environmental stress is via a mechanism known as phenotypic plasticity, which
allows an organism to express different phenotypes depending on the biotic or abiotic
environment in a way that may alter that organism's fitness. Acclimation temperatures can
potentially cause plastic (reversible and irreversible) changes in the response of individuals
to stressful experimental conditions that could increase their survival. The issue of whether
this acclimation will be beneficial to the organism or not remains contentious, with support
offered both for and against the idea of beneficial acclimation. The aims of the
investigation were to determine the thermal limits of five ameronothrid mite species
(Halozetes marinus, H marionensis, H belgicae, H. fulvus and Podacarus auberti) from
varying terrestrial habitats and to test whether there is beneficial acclimation on the thermal
traits. Along with the beneficial acclimation hypothesis several alternative hypotheses were
also tested. In addition, locomotor performance was determined as it has been suggested
that locomotion performance is a reliable and practical measure of potential fitness of
animals. The same hypotheses testing the effects of acclimation temperature on the thermal
limits were tested on three performance traits; performance breadth, optimum speed and
optimum temperature. Support for beneficial acclimation was found in the performance
breadth and optimum speed traits for all species except for Halozetes marinus. For the
optimum temperature trait the prediction for the compensation hypothesis was met and that
of the beneficial acclimation hypothesis rejected, with the only exception again being that
of H marinus. In the case of the locomotor performance traits the prediction for the beneficial acclimation hypothesis in the performance breadth and optimum speed traits are
the same for that of the compensation hypothesis, therefore the overall response of the
more terrestrial mite species is one of compensation. However, support for beneficial
acclimation was not found in the thermal limit traits of all five species, with the higher
acclimation temperatures (specifically 150 C) resulting in negative responses in LLT in H.
marinus and H. belgicae, and in ULT in H. fulvus. Phenotypic flexibility varied between
marine and terrestrial species. The less variable marine environment showed lower
flexibility than that of terrestrial species in the performance breadth trait and optimum
temperature trait, but there was a lack of variation between the marine and terrestrial
species in the temperature tolerance traits. These results show that the effects of
acclimation on various traits, especially fitness related traits, are complex and require more
attention if the consequences are to be fully explained. This study therefore provides
insight into the effects of acclimation on performance traits and thermal limit traits and has
implications for the evolution of plastic responses in terrestrial arthropods. / AFRIKAANSE OPSOMMING: Bewys vir wye ekologiese impakte as gevolg van vinnige klimaatsverandering is aan
die toeneem, met verdere verwarming wat voorspel word gedurende die volgende eeu. Dié
toename in verwarming het alreeds veroorsaak dat organismes hulle verspreidings
verander, of waar dit nie moontlik is nie, moet hulle stresvolle omgewingstoestande op 'n
ander wyse hanteer. Een moontlike manier om omgewingsstres te hanteer is deur gebruik te
maak van 'n meganisme wat bekend staan as fenotipiese plastisiteit, wat dit vir 'n
organisme moontlik maak om ander fenotipes te toon afhangende van die biotiese of
abiotiese omgewing in 'n wyse wat die organisme se fiksheid beinvloed. Temperatuur
akklimasie kan moontlik plastisiteit (omkeerbaar of onomkeerbaar) veranderinge in die
reaksie van individue tot stresvolle eksperimentele toestande tot gevolg hé, wat gevolglik
hulle oorlewing kan verhoog. Die kwessie of hierdie akklimasie wel voordelig vir die
organisme is of nie is steeds betwisbaar, met beide steun vir en teen die idee van voordelige
akklimasie. Die doel van hierdie ondersoek was om vas te stel wat die termiese limiete van
vyf ameronothrid myt spesies (Halozetes marinus, H marionensis, H belgicae, H fulvus
en Podacarus auberti) van verskeie terrestriële habitatte is, en om te toets of daar
voordelige akklimasie in die termiese eienskappe voorkom. Tesame met die voordelige
akklimasie hipotese is daar verskeie alternatiewe hipoteses ook getoets. Verder, is
bewegings prestasie vasgestelomdat dit al voorgestel is dat bewegings prestasie 'n
betroubare en praktiese mate van die potensiële fiksheid van 'n dier aantoon. Dieselfde
hipotese wat die effek van akklimasie temperatuur op die termiese limiete toets, is op drie
prestasie eienskappe getoets; prestasie wydte, optimale spoed en optimale temperatuur.
Bewyse vir voordelige akklimasie is gevind in die prestasie wydte en optimale spoed
eienskappe vir alle spesies behalwe Halozetes marinus. Vir die optimale temperatuur
eienskap was die voorspelling vir die kompensasie hipotese korrek maar dié van die voordelige akklimasie verkeerd, met H. marin us die enigste uitsondering. In die geval van
die bewegings prestasie eienskappe is die voorspelling vir die voordelige akklimasie
hipotese in die prestasie wydte en optimale spoed eienskappe die selfde as vir die
kompensasie hipotese. Daarom is die algemene reaksie vir die meer terrestriële spesies een
van kompensasie. Bewyse vir voordelige akklimasie is egter nie gevind in die termiese
limiet eienskappe van die vyf spesies nie, met die hoér akklimasie temperature (spesifiek
15° C) wat 'n negatiewe reaksie in LLT in H. marin us en H. belgicae, en in UL T in H.
fulvus veroorsaak het. Fenotipiese buigsaamheid het verskil tussen mariene en terrestriële
spesies. Die minder variërende mariene omgewing het 'n laer buigsaamheid in die prestasie
wydte en optimale temperatuur eienskappe getoon as die van terrestriële spesies, maar daar
was geen variasie tussen mariene en terrestriële spesies in die temperatuur toleransie
eienskappe nie. Die resultate wat hier voorgelê word wys dat die gevolge van akklimasie
op verskeie eienskappe, veral fiksheids verwante eienskappe, ingewikkeld is en vereis meer
aandag om die gevolge volledig te verduidelik. Hierdie studie verskaf dus insig in die
gevolge van akklimasie vir prestasie eienskappe en termiese limiet eienskappe en het
gevolge vir die evolusie van plastiese reaksies in terrestriële arthropoda.
|
463 |
The interaction between a keystone plant species and its dominant epiphyte on Marion Island : climate change implicationsBuwa, Ziphokazi Siyasanga 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: Climate has shown some remarkable changes over the past century, especially at the
polar and sub-polar regions. Southern Ocean Islands provide good models for studies
related to climate change effects, since effects may be evident in the short term and may
also be clearer. Marion Island is an example of such a system with a harsh abiotic
environment, and low species richness often vulnerable to change. Climate change is
predicted, and also reported, to have biological consequences on plant communities,
affecting the phenology, morphology, and the interaction between individuals and
species. This study examines the association between the keystone plant species, Azorella
selago Hook. (Apiaceace), and its dominant epiphyte Agrostis magellanica Lam.
(Poaceae). Two complimentary approaches were used, one observational and the other
experimental. The main objective for the observational study was to quantify bioticallyrelevant
microclimate temperature, as well as the morphology, epiphyte load and
phenology of A. selago at three different altitude sites on Marion Island. This provided
information on baseline variation for understanding specific variability in plant response
to the experimental part of this study, against which future patterns arising from
biological monitoring can be compared. Studying plants at different altitudes provides a
possible analogue for temperature-related climate change consequences for the ecology
of A. selago, and its interaction with A. magellanica. The microclimate temperature
associated with A. selago differed between the three sites examined. This difference was
related to local topographic conditions and altitude differences. Cushion size differed
distinctively between the three altitude sites, with this difference related to environmental
heterogeneity such as differences in age and substrate structure. Azorella selago annual
growth rate was estimated through stem length and the number of leaves on both exposed
and shaded stems. Within-site variability, as well as epiphyte cover were found to be the
contributing factors on A. selago annual growth rate. This highlights the importance of
site-specificity when estimating growth rate within and between different altitude sites.
Leaf characteristics differed between the sites, with this attributed to local habitat
conditions, such as topography, as well as epiphyte cover. As expected, the difference in
leaf size between exposed and shaded leaves demonstrated a larger specific leaf area on leaves shaded by A. magellanica. Agrostis magellanica abundance and density were
altitudinally related, with A. selago demonstrating facilitation effects on A. magellanica.
The trend shown in this study suggests that in spite of general facilitative effect of A.
selago on A. magellanica towards higher altitudes, the abiotic environmental threshold
for A. magellanica occurs at lower altitudes than it does for A. selago. Phenological
differences were also apparent between the three sites. The objectives of the experimental
part of this study were to quantify the effect of the dominant epiphyte, A. magellanica on
biotically-relevant microclimatic temperatures, as well as on the phenology and physical
condition of A. selago. Different treatments were applied to cushions at the three altitude
sites to examine the shading effect of epiphytic A. magellanica on cushion plants, as well
as the effect of treatment-related disturbance. Azorella selago microclimate temperature
showed no significant difference between treatments, suggesting that on average
epiphytic A. magellanica cover has no effect on cushion microclimate temperature. The
percentage of flower budding and flowering of A. selago was negatively related to
epiphyte cover. Cushion vitality was also responsive to epiphyte cover, with higher
vitality scores on low grass covered cushions than on high grass cushions. This shows
that A. magellanica competes with A. selago, while A. selago facilitates A. magellanica.
Heavy epiphyte numbers impose negative effects on A. selago vegetative and
reproductive performance, as well as cushion vitality. Therefore, the results of this
research show that the vegetative and reproductive performance of A. selago and cushion
vitality are likely to be negatively affected under ongoing climate change on Marion
Island if this brings about heavier epiphyte loads on this keystone cushion plant species. / AFRIKAANSE OPSOMMING: In die afgelope eeu het die klimaat in die Antarktiese en sub-Antarktiese gebiede
merkwaardige verandering getoon. Die Suidelike See Eilande dien as goeie modelle vir
studies verwant aan die gevolge van klimaatsverandering, aangesien die kort termyn
effekte in die gebiede duideliker mag wees in die toekoms. Marion Eiland is ‘n voorbeeld
van so ‘n sisteem, met ‘n ruwe abiotiese omgewing en lae spesies rykheid, wat vatbaar is
vir verandering. Daar word voorspel, en is reeds bevind dat klimaatsverandering
biologiese gevolge op plant gemeenskappe het, in terme van morfologie, fenologie en die
interaksie tussen individue en spesies. Hierdie studie ondersoek die assosiasie tussen die
hoeksteen plant spesie, Azorella selago (Apiaceace), en sy dominante epifietiese gras,
Agrostis magellanica Lam. (Poaceae). Die studie is op twee komplimentêre maniere
benader, naamlik deur waarneming en eksperiment. Die hoof doel van die studie was om
die biotiese belang van mikroklimaat temperatuur te kwantifiseer, en die hoeveelheid
epifiete, die morfologie en die fenologie van A. selago te bepaal by drie verskillende
hoogtes op Marion Eiland. Laasgenoemde het inligting verskaf oor die variasie in die
reaksie van plante tot die eksperimentele aspek van die studie, waarteen patrone vanaf
toekomstige biologiese beheer vergelyk kon word. Deur plante te bestudeer by
verskillende hoogtes bo seespieël word ‘n moontlike analoog vir die gevolge van
temperatuur-verwante klimaatverandering in terme van die ekologie van A. selago, en
laasgenoemde se interaksie met A. magellanica verskaf. Die mikroklimaat temperatuur
geassosieer met A. selago verskil tussen dié drie liggings. Die versil was verwant aan die
plaaslike topografiese toestande en die verskillende hoogtes bo seespieël. Die grootte van
die kussingplante het duidelik versil tussen die drie liggings, met die verskille verwant
aan die omgewing se heterogeneïteit, byvoorbeeld die verskille in ouderdom en substraat
struktuur. Azorella selago se jaarlikse groeitempo was bepaal deur die stingel lengte en
die aantal blare, op beide die wat oorskadu is deur die gras, en die was nie oorskadu is
nie. Daar is gevind dat die faktore wat bygedra het tot die jaarlikse groeitempo van A.
selago, varieër binne die verskillende liggings, en bedekking deur epifiete. Dit
beklemtoon die belang van spesifisiteit van ligging wanneer groeitempo in en tussen die
liggings van verskillende hoogtes bepaal word. Die blaar eienskappe het verskil tussen verskillende liggings, as gevolg van plaaslike habitat toestande, soos topografie en
bedekking deur epifiete. Soos verwag, het die blare wat oorskadu was deur A.
magellanica ‘n groter spesifieke blaar area getoon as blare wat blootgestel was. Die
hoeveelheid en digtheid van Agrosits magellanica was verwant aan hoogte bo seespieël,
met A. selago wat fasiliterende effekte toon op A. magellanica. Die tendens waargeneem
in hierdie studie is dat ten spyte van die algemene fasiliterende effek van A. selago op A.
magellanica, die abiotiese omgewingsdrempel op ‘n laer hoogte is vir A. magellanica as
vir A. selago. Fenologiese verskille was ook duidelik tussen die drie liggings. Die doel
van die eksperimentele deel van die studie was om die effek van die dominante epifiet, A.
magellanica, te bepaal op bioties relevante mikroklimaat temperature, asook op die
fenologie en fiesiese toestand van A. selago. Verskeie behandelings is aangewend op die
kussingplante by die drie liggings om die effek van skaduwee van die epifietiese A.
magellanica op die plante te bepaal, asook die effek van versteurings versoorsaak deur
die behandelings. Azorella selago se mikroklimaat temperatuur het geen betekenisvolle
verskille tussen behandelings getoon nie, wat voorstel dat epifitiese A. magellanica oor
die algemeen geen effek op die kussingplante se mikroklimaat temperatuur het nie. Daar
was ‘n negatiewe verwantskap tussen die hoeveelheid epifiete op A. selago en die
persentasie blomme en blomknoppe op die kussingplante. Die plante se vitaliteit was ook
afhanklik van epifiet bedekking, met ‘n hoër vitaliteit telling vir kussingplante bedek met
lae gras as die bedek met hoë gras. Dit toon dat A. magellanica met A. selago wedywer,
terwyl A. selago vir A. magellanica fasiliteer. Hoë epifiet getalle het negatiewe effekte op
A. selago se vegetatiewe en reproproduktiewe nakoming, asook die kussingplante se
vitaliteit. Die resultate van hierdie studie toon dus dat die vegetatiewe en reproduktiewe
nakoming van A. selago en kussingplant vitaliteit heel moontlik negatief geaffekteer sal
word indien klimaatsverandering op Marion Eiland hoër epifiet getalle op die sleutel
kussingplant spesie tot gevolg sal hê.
|
464 |
Seismotectonics Of The Andaman-Nicobar Plate Boundary And Evaluation Of 2004 Deformational And Depositional Features Towards Assessing Past Tsunamigenic EarthquakesAndrade, Vanessa Mary Rachel 12 1900 (has links) (PDF)
Tsunami hazards were greatly underestimated along the coasts of countries bordering the northeastern Indian Ocean until the occurrence of the 26 December 2004, Mw 9.2 earthquake and its ensuing tsunami. Sourced off the coast of northern Sumatra, on the plate boundary between the Indo-Australian and Eurasian plates, the rupture of the 2004 earthquake propagated ~1300 km northward. The magnitude of this earthquake and the reach of its tsunami exceeded all known precedents, based on instrumental and historic records. The coseismic deformational and post-tsunami depositional features facilitated opportunities to conduct tsunami geology studies along the coasts of countries bordering the Indian Ocean. Several questions are being posed, the answers of which have implications for tsunami hazard assessment. How did this plate boundary behave prior to and after the great earthquake? Was the 2004 earthquake the first of its kind on the Sumatra-Andaman plate boundary? If it had a predecessor, when did it occur and was it a true predecessor in terms of its rupture dimensions and tsunamigenic potential? What types of depositional evidence are preserved and how can we use them to develop the history of past tsunamigenic earthquakes? Researchers are exploring the affected regions and using the imprints left by the 2004 event, to address these questions.
There are two components to this study: one, a seismotectonic analysis of the region from the perspective of plate driving forces and their relative roles in the interseismic and post-seismic phases. This study uses global data catalogs like the NEIC PDE (National Earthquake Information Centre Preliminary Determination of Epicenters) and the Global Centroid Moment Tensor (CMT) solutions for earthquake source parameters to understand the along-strike variations in seismicity patterns before and after the 2004 earthquake.
The 2004 experience was unprecedented in South Asia. Unaffected by tsunami hazards in the past, tsunami geology is a nascent field for most South Asian researchers. Very little background field data is available on the deformational features of great earthquakes along this plate boundary and the depositional characteristics of extreme coastal surges, such as tsunamis and storms. Where do we begin our search for evidence of past tsunamigenic earthquakes? How best can we use the 2004 tsunami and its deposits as a proxy? What problems are encountered in the interpretations? This thesis addresses these questions in part and presents observations from the Andaman Islands (the ~400 km, northern segment of the Sumatra-Andaman subduction zone) and the southeast coast of India, towards developing a reliable database of tsunami geology for 2004-type events.
The premise is that regions affected by the 2004 earthquake are more likely to conserve signatures from older events. Based on the stratigraphic context of the proxy and quality of age estimates, this work presents evidence for past earthquake related deformation and tsunami deposition. In this work we use deformational and depositional features from the Andaman Islands, falling within the 2004 rupture zone and from one location on the Tamil Nadu coast of India (Kaveripattinam). From a perceptive understanding of the features related to tectonic deformation of the Sumatra-Andaman subduction zone, we have selected the Andaman segment that demonstrates explicit evidence for deformation and tsunami deposition through geomorphological and stratigraphic features, which are key to our exploration. A gist of each chapter is given below.
The introduction (chapter 1) presents the background, motivation and scope of this work and the organization of this thesis, also summarizing the contents of each chapter. Chapter 2 provides a review of literature on subduction zone earthquakes and updates on tsunami geology, to place this study in the global context. The next two chapters discuss the seismotectonics of the Sumatra-Andaman plate boundary, the important earthquakes and their source processes. In chapter 3 we discuss the Andaman segment (from 10–15° N), characterized by relatively lower level seismicity, but distinctive, as it falls within the northern limit of the 2004 rupture. The deformational and depositional features here are better exposed due to availability of land straddling the hinge line separating the areas of 2004 uplift and subsidence. Here, the pre-2004 earthquakes used to occur along a gently dipping subducting slab, up to a depth of about 40 km. Post-2004, the earthquakes moved up-dip, extending also to the outer-rise and outer-ridge regions, expressing post-earthquake relaxation [Andrade and Rajendran, 2011]. The southern Nicobar segment (5–10° N) differs from the Andaman segment in its style of deformation and seismic productivity. The decreasing obliquity of convergence, the likely influence of a subducting ocean ridge on the subducting plate and the character of the subducting oceanic plate make this segment distinctly different. In chapter 4 we present an analysis of its seismotectonic environment based on the well-constrained focal mechanisms of historic and recent earthquakes. We report that left-lateral strike-slip faulting on near N-S oriented faults control the deformation and the style of faulting is consistent to ~80 km within the subducting slab [Rajendran, K. et al., 2011]. The 11 April 2012 sequence of earthquakes on the subducting oceanic plate, between the Sumatra Trench and the Ninety East Ridge are the more recent among the oceanic intraplate earthquakes that demonstrate the reactivation of N-S oriented fossil fractures.
The limited availability of land and the 2004 coseismic deformation dominated by subsidence, followed by prolonged waterlogging makes exploration difficult in the Nicobar segment. Thus, we focus on the Andaman Islands for deformational and depositional evidence, using observations that can be corroborated through multiple proxies and depositional environments that are not prone to other coastal surges, such as cyclones and storms. The criteria for selection of sites, evaluation of deposits and determination of limiting ages are discussed in chapters 5 through 9. In chapter 5 we discuss different types of coastal environments and their response to high-energy sea surges. We also give a brief review of the comparative analyses of storm and tsunami deposits, a highly debated issue and then discuss important characteristics of these two deposits, using examples from the 2004 tsunami and the 2011 Thane cyclone that affected parts of the Tamil Nadu coast.
An important component of tsunami geology is the ability to identify and select datable material from tsunami deposits and chose an appropriate method for dating (chapter 6). The types of material used vary from peat layers, peat-rich soil, gastropod shells, wood, charcoal, organic remains such as bones, coral fragments, pottery sherds and buried soil. Techniques such as AMS Carbon-14 and Thermoluminescence are commonly used with appropriate calibrations and corrections. In addition to the dates generated in this study (based on wood and shell dates) we use some previous dates from the entire stretch of the rupture within the Indian Territory and assign a relative grading to these ages, based on the quality criterion evolved in this study. We believe that this is the first attempt to segregate age data obtained from coastal deposits, and assign them a specific quality grading based on their environment of deposition and the type of material dated.
Chapter 7 presents results of our investigations in the Andaman Islands, which cover ~30% of the rupture area. A coseismically subsided mangrove from Rangachanga (Port Blair, east coast of South Andaman) led us to a former subsidence during AD 770–1040, which we believe is the most convincing evidence for a previous tectonic event. Data based on inland deposits of coral and organic debris yielded a younger age in the range of AD 1480–1660. Both these dates fall in the age brackets reported from other regions of this plate boundary (mainly Sumatra) as well as distant shores of Sri Lanka, Thailand and mainland India. To understand the nature of distant deposits, we present observations from Kaveripattinam, an ancient port city on the east coast of India, where a high-energy sea surge deposit, found 1 km inland is attributed to a paleotsunami. The inland location of this archeological site at an elevation of 2 m and characteristics of the deposit that help discriminate it from typical storm deposition provide clinching evidence in favor of a 1000-year old regional tsunami (chapter 8).
In chapter 9 we discuss the results of our study. We evaluate the nature of deformation/deposition and the calibrated age data in the context of their environments. Ages based on the organic material associated with coral debris (at Hut Bay and Interview Island) and the remains of mangrove roots, 1 m below the present ground level (at Port Blair) are considered as reliable estimates, due to their sheltered inland location and the in situ root horizon used for dating. Age data from Kaveripattinam is also considered reliable, based on its inland location beyond the reach of storm surges, sediment characteristics typical of tsunami deposition and ages based on multiple methods and samples. The age data based on the sites presented in this thesis are more conclusive about the 800 to 1100 AD and 1250 to 1450 AD tsunamis, and the former is represented from regions closer to the 2004 source as well as distant shores reached by its tsunami.
Chapter 10 presents our conclusions and the scope for future studies. We present this as the first study of its kind in the northeastern Bay of Bengal, wherein the coseismic vertical coastal deformation features along an interplate subduction boundary and a variety of tsunami deposits are used to categorize depositional environments and ages of paleoearthquakes and tsunamis. To our knowledge, this is the first study of its kind where the effects of a recent tsunami have been used to evaluate paleodeposits based on their respective environments of occurrence. Our results have implications for tsunami geology studies in coastal regions prone to tsunami hazard.
|
465 |
Patterns of variability in Azorella selago Hook. (Apiaceae) on sub-Antarctic Marion Island : climate change implicationsNyakatya, Mawethu Justice 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: Understanding the responses of species to climate change is a scientific
problem that requires urgent attention, especially under current conditions of
global climate change. The large and rapid rates of climate change reported
for sub-Antarctic Marion Island makes the island highly suitable for studying
the biotic consequences of climate change. Furthermore, the extreme
environments on the island result in a close coupling of the biotic (e.g.
population dynamics) and abiotic (e.g. climate) factors. Therefore, examining
the response of the dominant and keystone plant species on the island,
Azorella selago Hook. (Apiaceae), to climate-associated environmental
change (e.g. temperature) may provide insight into how A. selago and the
associated species communities will be affected by climate change. This
study described the variability in microclimate temperatures associated with A.
selago across altitudinal gradient and between the eastern and western sides
of Marion Island. Microclimate temperatures were also compared to the
island’s Meteorological data to determine variation between temperatures
experienced by A. selago cushion-plants in the field and those recorded at the
island’s Meteorological Station. Temperature variation inside and outside A.
selago cushions was also examined. Azorella selago cushions were found to
have a buffering effect on temperature, such that species occurring
epiphytically on A. selago experience more moderate temperatures than the
surrounding environment. However, A. selago were found to experience more
extreme temperatures than temperatures recorded at the Meteorological
Station. Therefore, A. selago may possibly experience greater environmental
warming than recorded by the Meteorological Station. While temperatures
decline with altitude, temperature conditions on the western side of the island
were more temperate than the eastern side. This presents the first record of
temperature conditions on the western side of the island. This study also
quantified fine-scale (e.g. within-site) and broad-scale (e.g. island-wide)
variability patterns of A. selago (morphology, phenology, and epiphyte load)
across Marion Island. Altitudinal gradient and climatic exposure at different
sides of the island were used to understand the likely effects of climate
associated environmental change on this dominant component of the fellfield habitat. Site-specific processes were found to determine the spatial structure
of A. selago characteristics at fine-scales. However, broad-scale observations
established strong responses of A. selago characteristics to altitudinal
gradients and different sides of the island. Azorella selago morphological
features (e.g. plant size and leaf size) were found to be more responsive to
differences between the eastern and western sides of the island than to
altitudinal gradient. Azorella selago micro-morphological features (e.g. leaf
trichomes and stomatal densities) were also found to be more responsive to
climatic exposure at different sides of the island than to altitudinal gradient.
However, differences in A. selago epiphyte density (e.g. Agrostis magellanica)
and phenology resembled microclimate temperatures in that they were more
responsive to altitudinal gradient than to side of the island differences. From
these results it can therefore be predicted that the A. selago of Marion Island
is likely to be morphologically fairly resilient to moderate climatic shifts,
although at lower altitudes and on the eastern side of the island, it may be
outcompeted by the epiphytic grass, Agrostis magellanica. The results also
suggest that the warming climate of Marion Island may result in an early
occurrence of phenological processes particularly at lower altitudes and the
eastern side. Azorella selago at lower altitudes and on the eastern side of
Marion Island are therefore expected to largely show more symptoms of
climate change (e.g. warming) on this species. Azorella selago is also
predicted to move up altitudinal gradients in response to warming. / AFRIKAANSE OPSOMMING: ’n Begrip van hoe spesies reageer op klimaatsverandering is ’n wetenskaplike
vraag wat onmiddellike aandag benodig, veral onder huidige globale
klimaatsverandering. Die groot en snelle tempo waarteen klimaatsverandering
waargeneem word op sub-Antarktiese Marion Eiland, maak die eiland hoogs
geskik om die biotiese gevolge van klimaatsverandering te bestudeer. Verder
veroorsaak die uiterste omgewing van die eiland tot ’n nabye koppeling
tussen die biotiese (bv. populasie dinamika) en abiotiese (bv. klimaat) faktore.
Dus, deur die reaksies van ’n dominante- en sleutel-spesie op die eiland,
Azorella selago Hook. (Apiaceae), op klimaat-geassosieerde omgewings
verandering (bv. temperatuur) te bestudeer, mag insig verskaf hoe A. selago
en geassosieerde spesie gemeenskappe geaffekteer sal word deur
klimaatsverandering. Hierdie studie beskryf die wispelturigheid in mikroklimaat
temperature geassosieer met A. selago oor ’n hoogte gradiënt asook tussen
die oostelike en westelik dele van Marion Eiland. Mikroklimaat temperature
was ook vergelyk met die eiland se Meteorologiese data met die doel om die
mate van variasie tussen temperature verduur deur A. selago kussing-plante
in die natuurlike omgewing met die van die eiland se Meteorologiese stasie te
vergelyk. Temperatuur variasie binne en buite A. selago kussing-plante is ook
vasgestel. Dit was gevind dat Azorella selago kussing-plante die temperatuur
buffer, met die gevolg dat spesies wat epifities op A. selago voorkom, meer
gematigde temperature ondervind as die onmiddellike omgewing om die
plant. Daar is egter gevind dat A. selago meer uiterste temperature ondervind
as temperature gemeet by die Meteorologiese stasie. Dus mag A. selago
groter omgewings verwarming ervaar as wat temperature gemeet by die
Meteorologiese stasie dui. Terwyl temperatuur afneem met ’n toename in
hoogte, was temperatuur aan die westekant van die eiland mere gematig as
die oostekant. Dit verskaf die eerste rekord van temperatuur toestande aan
die westekant van die eiland. Hierdie studie bepaal ook die fyn-skaal (e.g.
binne-terrein) en groot-skaal (e.g. oor die eiland) variasie patrone van A.
selago (morfologie, fenologie, en epifiet lading) oor Marion Eiland. Die hoogte
gradiënt en klimaat blootstelling aan verskillende kante van die eiland is
gebruik om die waarskynlike effekte van klimaats-geassosieerde omgewings verandering op die dominante deel van die felfield habitat te verstaan. Daar is
gevind dat terrein spesifieke prosesse die ruimtelike struktuur van A. selago
se klein-skaal eienskappe bepaal. Groot-skaalse waarnemings dui egter ’n
sterk antwoord van A. selago eienskappe op die hoogte gradiënt en aan
verskillende kante van die eiland. Azorella selago morfologiese eienskappe
(e.g. plant- en blaar grootte) is gevind om meer te reageer op verskille tussen
oostelike en westelike kante van die eiland as op die hoogte gradiënt.
Azorella selago mikromorfologiese eienskappe (e.g. blaar trigome en stomata
digtheid) is ook gevind om meer te reageer op omgewings blootstelling tussen
verskillende kante van die eiland as op die hoogte gradiënt. Verskille in A.
selago epifiet digtheid (e.g. Agrostis magellanica) en fenologie het egter
mikroklimaat temperature gevolg, in dat beide meer gereageer het op die
hoogte gradiënt as eiland-kant verskille. Hierdie resultate voorspel dus dat dit
waarskynlik is dat A. selago van Marion Eiland morfologies redelik
terugspringend sal wees ten opsigte van matige klimaatsverandering, al mag
dit uitgekompeteer word deur die epifitiese gras, Agrostis magellanica by lae
hoogtes en aan die oostekant van die eiland. Hierdie resultate dui ook dat
verwarming van Marion Eiland se klimaat ’n vervroeging van fenologiese
prosesse mag hê, veral by lae hoogtes en aan die oostekant van die eiland.
Dus word dit verwag dat Azorella selago by lae hoogtes en aan die oostekant
van Marion Eiland om meer simptome van klimaatsverandering (e.g.
verwarming) te dui. Dit word ook voorspel dat Azorella selago opwaarts teen
die hoogte gradiënt sal beweeg in reaksie tot verwarming.
|
466 |
Different stories about the same place : interpreting narrative, practice and tradition in the East Kimberley of northern Australia and the Aru Island of Eastern IndonesiaCorrigan, Brendan January 2007 (has links)
This thesis interrogates the relationship of archaeological models and indigenous understandings of origins in the East Kimberley region of Northern Australia and the Aru Islands of Eastern Indonesia. Archaeological models of prehistoric migration construct these places as part of the same landmass in the recent human period and at times of lower sea levels. Yet, the indigenous groups who currently inhabit these places assert and rely upon their localised understandings of autochthony and mythological creationism. The existence of these competing models has led me to examine the degree to which the practice of archaeology in these locations constructs human prehistory in a way that necessarily disempowers the indigenous cosmology there. Below I examine the construction and content of these different stories about the same place to show how it is that they are essentially competing, conflicting and contradictory claims to truth. I show how each of these asserted cosmological positions emerge from the various cultural systems that sponsor and perpetuate them and I pay special attention to the role of institutionally authorised experts within each of the cosmological positions described. I also seek to demonstrate the ways in which the distribution of expert knowledge plays a core role in a naturalised social order and the ongoing construction of cultural identity in their respective communities. I then interrogate the relationships that these differing forms of knowledge have with each other - paying close attention to the specifics of context in which they are evoked. I conclude that the examination of how these competing claims to truth are distributed in space reveals their influence in the ongoing construction of identity in their respective communities.
|
467 |
The partition of the Samoan Islands, 1898-1899Kennedy, Paul M. January 1970 (has links)
No description available.
|
468 |
Les îles d'Abou Moussa, de la Petite Tumb et de la Grande Tumb : une souveraineté contestée entre la République islamique d'Iran et les Émirats arabes unis / The islands of Abu Musa, Lesser Tunb and Greater Tunb : a sovereignty dispute between the Islamic Republic of Iran and the United Arab EmirateRazavi, Seyed Abdoljalil 15 October 2016 (has links)
Dans cette recherche, nous avons opté pour une méthode à la fois descriptive, analytique et documentaire, fondée sur la collecte de données : enquêtes, entretiens et ressources de bibliothèque.Les résultats montrent qu’un pays nouvellement créé a besoin, pour se développer, de s’appuyer sur un sentiment d'intégration et d'identité nationale. Il semble que ce soit la raison fondamentale de la revendication par les Emirats arabes unis de ces îles appartenant à l’Iran, seul pays non arabe du golfe Persique. A travers ces revendications, les Emirats arabes unis ont pour objectif la création d’un Etat-nation. / In this research, we opted for a method that is descriptive, analytical and documentary, based on the collection of data in the forms of surveys, interviews and library resources. The results show that a newly created country, for its development, needs to build on a sense of integration and national identity. It seems that this is the fundamental reason for the claim by the United Arab Emirates on these islands belonging to Iran, the only non-Arab country of the Persian Gulf. Through these claims, the United Arab Emirates aim to creat a nation -state.
|
469 |
Mapping and analyzing the Florida Reef Tract in Palm Beach County in relation to major storm events in a GIS databaseUnknown Date (has links)
The Florida Reef Tract in Southeast Florida is made up of hard-bottom formations. The shape and size of the tract is constantly changing. One major factor contributing to these changes is the movement of sand. This is influenced by location-based, human-induced, and natural factors. These shifting sands cover or uncover reef structure. Images of the Florida Reef Tract in Palm Beach County were analyzed by the Department of Geosciences at Florida Atlantic University, using a partially automated method of mapping. There are notable changes in reef structure throughout the years 2004-2006, in which many major storm events occurred in the region. A time series analysis was conducted throughout these years. Losses and gains of reef structure were quantified and compared throughout the county as a whole, in beach renourishment project areas, and inlet intervals. Trends suggest that the major storms of 2004-2006 may have had effects on the reef tract. / by Joseph G. Pitti. / Thesis (M.A.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.
|
470 |
The Sino-Japanese Dispute over the Diaoyu Islands and Taiwan¡¦s Strategy: A Case Study of the Minjin 5179 IncidentLu, Hsing-Shuo 06 September 2012 (has links)
Dispute over the sovereignty of Diaoyu Islands (Senkaku Islands) implicates peace in East Asia. These islands were under Chinese control for five hundred years in the Ming and Qing Dynasties, and were used as sailing coordinates for imperial Chinese missions to the ancient Ryūkyū Kingdom and as part of national defense.
Under the control of the Qing Dynasty, the Diaoyu Islands were affiliated with Taiwan. In 1894, the Qing was defeated by Japanese in the Sino-Japanese War and was forced to secede Taiwan and its surrounding islands to Japan in 1985. After World War II, the Diaoyu islands were under the United States¡¦ occupation. In 1972, the United States reverted administrative control over these islands to Japan. The Diaoyu Islands have so far been separated from the Chinese rule for over a century.
Due to the intervention of the United States, the Diaoyu Islands were not returned to China or Taiwan after the defeat of Japan in 1945. In the 21st Century, as the resources on earth are gradually depleted, the sovereignty of the Diaoyu Islands has become a ferocious competition among China, Japan, and Taiwan due to its rich ocean resources. At present, the islands are under de facto control by Japan; resolution of the problem has troubled Taiwan, China, and Japan. On September 7, 2010, ¡§Minjin Fishing Boat No. 5179¡¨ collided with Japanese Coast Guard patrol boats. This thesis uses this incident as a case to study the Sino-Japanese conflict on the Diaoyu Islands.
|
Page generated in 0.0549 seconds