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Studies of the Passive Dispersal of Viable Algae and Protozoa by Aquatic and Terrestrial BeetlesMilliger, Larry Edward 08 1900 (has links)
The purpose of the present study was to determine the relative importance of aquatic and terrestrial beetles as possible vehicles in the passive overland dispersal of viable microorganisms.
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Seed Dispersal of the Cocoplum (Chrysobalanus icaco) by Gopher Tortoises (Gopherus polyphemus) in Southeastern FloridaUnknown Date (has links)
Gopher tortoises (Gopherus polyphemus) are keystone species mainly due to their burrow construction. Gopher tortoises can also impact the plants around them, but it is rarely quantifiable due to constraints in dispersal studies including time period and seasonality of fruit. The objective of this study was to measure the effect gut-passage has on a native Florida stone-pitted shrub, the cocoplum bush (Chrysobalanus icaco), as well as to attempt to model the relationship between the gopher tortoise and the plant using our unique field site. This study shows that gut-passage has a significant effect on the germination rate of the cocoplum, allowing it to germinate faster than control groups. This study also found that a model involving covariates relating to tortoise movement as a predictor for cocoplum intensity was favored over a homogeneous null model. We believe the pattern of plants is nonrandom and relates to the gopher tortoise’s seed dispersal. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection
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The “suitcase hypothesis” – can eddies provide a pathway for gene flow between Madagascar and KwaZulu-Natal?Ockhuis, Samantha Angelique Natasha January 2016 (has links)
Thesis (MTech (Oceanography))--Cape Peninsula University of Technology, 2016. / Similarities in marine fauna found off the coasts of southern Madagascar and KwaZulu-Natal (KZN, South Africa) led to the development of the “Suitcase Project”, with the aim of establishing whether eddies that form off southern Madagascar may package and transport biological material, as if in a suitcase, across the Mozambique Channel. In pursuit of this question, sampling was conducted on the southern Madagascan shelf and along a transect across a cyclonic eddy which originated off the southern tip of Madagascar, between the 15th and 23rd of July 2013. Bongo nets (300 and 500 μm-mesh) and a neuston net (900 μm-mesh) were used to collect zooplankton within the upper 200 m and at the surface, respectively. Samples were sorted for meroplankton (larval stages of fish and benthic invertebrates) under a stereo microscope, particularly seeking species known to be common to both the east coasts of Madagascar and South Africa and, thus potential indicators of connectivity between these regions. Larvae of crabs, rock lobster, and fish were used for DNA barcoding. Zooplankton biovolume and abundance were compared between the eddy core, eddy periphery and outer regions of the eddy, as well as stations from the Madagascan shelf. Mean neuston biovolume on the Madagascan (0.08 mL m-3) was not significantly higher than that in the eddy (0.06 mL m-3). Mean bongo biovolume in the upper 200 m was much higher on the Madagascan shelf (0.62 mL m-3) than in the eddy (0.16 mL m-3) although only 2 stations were sampled on the shelf. Highest biovolume in the eddy was recorded in the west eddy zone (0.25 mL m-3) and west outer zone (0.23 mL m-3), which was not statistically significantly higher than the eddy core (0.12 mL m-3) and east eddy zone (0.17 mL m-3). Meroplankton was comprised of coastal origin taxa and was most abundant on the shelf and in the eddy perimeters. Larval goat-fish, Parupeneus fraserorum was identified, a newly described mullid, and has been recorded on both the coasts of Madagascar and KZN, SA. Larvae of coastal invertebrate species identified, include the squat lobster Allogalathea elegans and camel shrimp Rhynchocinetes durbanensis. Other larval fish identified, but not found in high abundance include the families of reef associated fishes, for example: Apogonidae, Labridae, Pomacentridae, Priacanthidae, Serranidae and Sparidae. Higher zooplankton biovolumes, larval abundances and reef-associated larval assemblages found on the Madagascan shelf and in the periphery of the cyclonic eddy compared to the core in this study provide support for the suitcase hypothesis that planktonic organisms are entrained within eddies as they propagate south-westwards of the Madagascan shelf. However, further studies are required to determine whether planktonic larvae are able to cross the Mozambique Channel and reach the KZN coast in time to settle.
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Testing hypotheses in molecular ecology: genetic exchange and hybrid performanceHolleley, Clare Ellen, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW January 2009 (has links)
Population structure, gene flow and dispersal are some of the most commonly estimated population parameters in population genetics, evolutionary biology and conservation genetics. The primary aim of thesis is to test the precision and accuracy of genetic estimates of population structure, gene flow and dispersal. The controlled replicated Drosophila melanogaster experiments of known effective population size (Ne = 14.3) and dispersal rate (m = 0.0025 - 0.04) all adhered to Wright??s demographic island model. Three statistical approaches were empirically tested: 1) the conversion of population structure to gene flow using FST, RST, SHUA and PhiST ; 2) the private alleles method to estimate gene flow; 3) a Bayesian assignment method to estimate dispersal (BAYESASS 1.2). Even in the best-case scenario, almost all current methods except SHUA significantly underestimate population structure, and consequently overestimate gene flow and dispersal when applied to real populations. It was crucial to ensure that the manipulated rate of gene flow was correctly defined. This led to three supporting investigations of hybrid performance, inversion polymorphisms and effective population size. The hybrid performance investigation demonstrated that the manipulated rate of gene flow had not been unexpectedly inflated by hybrid vigour or reduced by breakdown. These experiments also demonstrated that close inbreeding is not a necessary precondition for hybrid vigour or breakdown, which is important for conservation strategies involving induced dispersal. The investigation of inversion polymorphisms ensured that the manipulated rate of gene flow was not affected by selection on inverted regions. The effective population size investigation used a temporal estimation method to confirm that the Ne was accurately predicted by an N:Ne ratio of 0.286. Additionally this experiment showed that the single-sample estimation methods implemented by ONeSAMP or LDNE resulted in downwardly biased estimates of Ne in structured populations. In conclusion these results call into question the confidence that biologists may have in some of the most widely used molecular tools in conservation biology.
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Factors influencing overland mobility of Cryptosporidium OocystsKaucner, Christine E., Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2007 (has links)
The mechanisms responsible for overland transport of faecal pathogens, particularly Cryptosporidium oocysts, from animal sources to water bodies are not fully understood. Surface properties of microbes, such as electrostatic charge and hydrophobicity, are thought to contribute to their aggregation and attachment to solid surfaces. There is conflicting evidence that methods used to purify Cryptosporidium oocysts from faecal material may affect the oocyst surface, leading to biased conclusions from transport studies. By studying oocyst surface properties, aggregation and soil attachment, this thesis addressed whether oocyst purification methods influence overland transport studies, and whether oocysts are likely to be associated with particles during transport. When using the microbial adhesion to hydrocarbon (MATH) assay with octane, oocyst hydrophobicity was shown to be method and isolate dependent, with oocysts displaying moderate to high hydrophobicity in 0.01 M KNO3. There was no observed attachment, however, to the hydrophobic octyl-SepharoseTM bead ligands when using the same suspension solution. Oocyst age did not appear to influence their hydrophobicity. A small but statistically significant proportion of oocysts displayed a net negative surface charge as observed by their attachment to an anion exchange ligand (DEAE). There was no difference in hydrophobicity or surface charge observed between purified oocysts and oocysts that had been extracted without the use of harsh chemicals and solutions with dehydrating properties. Purified oocysts did not aggregate at pH values between 3.3 and 9.0, nor in solutions lower than 0.59 M in ionic strength at a pH 2.7 which is approaching the reported isoelectric point of oocysts. This finding suggests that oocysts may not form aggregates under general environmental conditions. The association of purified oocysts with soil particles was observed in settling columns. Attachment to soil particles was not conclusive since the settling of the soil particles may have entrained single oocysts. Nonetheless, approximately 27% of oocysts were estimated to be unbound to soil or associated with small soil particles. Hence models for oocyst overland transport should consider a significant fraction as single entities or associated with soil particles less than about 3 μm in size.
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Larval dispersal and population genetic structure of brachiopods in the New Zealand fiordsOstrow, D. Gigi, n/a January 2007 (has links)
New Zealand�s fourteen deep-water fiords have complex physical and hydrographic features as well as strong environmental gradients, all of which may influence the population structure of organisms that inhabit the fiords. I examined the population structure of the brachiopod Terebratella sanguinea over ecological and evolutionary time scales in relation to physical and hydrographic features of the fiords. To further explore the role of larval dispersal in this system, comparisons between population genetic structure of T. sanguinea and a brachiopod with a contrasting larval dispersal strategy (Liothyrella neozelanica) were made.
Aspects of the life history of the articulate brachiopod Terebratella sanguinea were measured. I measured density and size throughout Doubtful Sound and growth at outer (5 km from outer coast) and inner fiord sites (13.5 km from outer coast). Additionally, reproductive periodicity was measured at a single site within Doubtful Sound. Terebratella sanguinea occurred at significantly lower densities and was significantly smaller at the outer fiord site (p < 0.05), however growth rates between an inner and outer fiord site did not differ significantly. Terebratella sanguinea was found to have separate sexes and synchronous maturation of oocytes with spawning occurring in the austral winter. These results indicated that, on an ecological time scale, the environmental gradient of the fiords influences aspects of T. sanguinea population structure.
In order to determine the influence of the fiord environment on genetic population structure, patterns among T. sanguinea from across Fiordland were assessed using two genetic markers, and these data were compared to hydrodynamic variables. Ten sites (322 individuals) were included in a preliminary allozyme analysis, and 20 sites (358 individuals) were used for the amplified fragment length polymorphism (AFLP) analysis. Patchy genetic differentiation was revealed with both markers, and a break between Long Sound and the other Fiordland sites was detected with AFLP markers. My results suggest hydrodynamic features of this region may isolate organisms that can disperse only during a planktonic larval phase, however this isolation is visible in genetic patterns only at the most extreme values of the hydrodynamic variables.
To better understand how the fiord environment influences population structure of organisms that disperse via planktonic larvae, I compared population genetic structure of two sympatric brachiopod species that differ in planktonic larval duration. Genetic analysis using the AFLP technique revealed population structuring corresponding to the contrasting modes of larval dispersal. AMOVA analysis indicated Liothyrella neozelanica, a brachiopod that broods its larvae, had more limited exchange among sites within a fiord than did T. sanguinea, a brachiopod that does not brood its larvae. In general, the fiord hydrographic conditions may be creating opportunities for local genetic differentiation (for example Long Sound) in organisms capable of longer distance dispersal, but organisms with lower potential for dispersal are more strongly influenced by ontogeny than by hydrography.
Understanding the population structure of some of the marine fauna of Fiordland is an important cornerstone for the developing management plan for the area. Conservation of the underwater resources of this World Heritage Area can be successful if the structure of the system and the mechanisms driving this structure are taken into account.
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Confidential and Resilient Store of Persistent Web ObjectsMohan, Anoop 01 January 2009 (has links)
Persistent and secure store for web objects is an attractive feature in today?s web world and possess a good potential for exploration. Persistence of a storage mechanism refers to its ability to store an object for extremely long time periods. Resilience refers to its fault tolerance ability or its ability to retrieve the object completely even if a part of that object is lost due to any catastrophic failures like disk failure. It is also important that this storage mechanism is able to store this object in a secure manner. In the current world, usability of any storage mechanism is enhanced multiple times if it could be used from a web interface. This thesis considers different techniques that provide these properties and proposes a storage mechanism that makes use of information dispersal techniques that is suited to store data securely, with an emphasis on availability and resilience. A working prototype of this storage mechanism was developed as a part of this thesis and is made available as a library for program developers. This library provides APIs to store and retrieve data as well as a daemon for error control. The APIs to store and retrieve data also accepts HTTP requests, which increase its usability to web developers. The performance of this prototype was measured and is presented using graphs. Finally a demonstration of the applications of this prototype is also provided.
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The Effects of Large Terrestrial Mammals on Seed Fates, Hoarding, and Seedling Survival in a Costa Rican Rain ForestKuprewicz, Erin Kathleen 07 May 2010 (has links)
Terrestrial mammals affect numerous aspects of plant demography, colonization, and community structure in Neotropical forests. Granivorous mammals destroy seeds via seed predation and seedlings through herbivory, negatively affecting plant fitness. Mammals can also positively affect plants by dispersing or hoarding seeds. Seed fate outcomes are contingent on the interaction between mammal seed handling strategies and the intrinsic anti-predation defenses possessed by seeds. In field experiments at La Selva Biological Station, I investigated how collared peccaries (Pecari tajacu) and Central American agoutis (Dasyprocta punctata) affect five species of large seeds that have various defenses against predation. Overall, peccaries consumed and killed most non-defended and chemically-defended seeds but they could not destroy seeds with physical defenses. Agoutis killed non-defended and physically-defended seeds, but not seeds with chemical defenses. Using seeds of Mucuna holtonii, I investigated how chemical and structural defenses deter mammal and insect seed predation respectively. I also determined how endosperm removal by invertebrates affects seed germination and seedling biomass. Chemical defenses protected seeds from rodents, but not ungulates that digest seeds via pregastric fermentation. Physical defenses protected seeds from invertebrate seed predators, and removal of endosperm negatively affected both seed germination and seedling growth. To determine how scatter-hoarding by agoutis affects seed escape from seed predators, germination, and seedling growth, I created simulated agouti hoards. I also investigated how mammals affect young seedling survival. Hoarding enhanced seed survival, germination, and seedling growth for most species of seeds. Terrestrial mammals killed some seedlings via seed predation rather than by herbivory. Overall, large mammal activity in La Selva negatively affected seed and seedling survival and this likely influences many aspects of forest dynamics.
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Siberian jay friendship test : A study on group cohesionKozma, Radoslav January 2011 (has links)
Group and family living is an integral part of many animals’ ecology. Thus the behavior became associated with plenty of advantages as well as disadvantages. However, rarely has the actual concept of the group been investigated. Questions such as, “What constitutes a ‘group’?” and “Do the individuals within these ‘groups’ associate with each other frequently enough to actually enjoy the benefits of group living?” are seldom asked. With these questions in mind, the aim of this study was to use Siberian jay (Perisoreus infaustus) individuals in their territories to explore and shed more light on the issue of the extent of group living. A working definition of a ‘group’ was made and subsequently the birds were observed in their natural habitat in northern Sweden during several seasons. Consequently, a pair-wise coherence index (CI) was created to quantify the levels of association between the individuals within each territory in order to investigate which possible factors affect the extent of the observed cohesion. Results of the study indicate that pair-wise cohesion was strongly dependent on the kinship of the birds. Moreover, it was found that the alpha and kin birds had significantly higher coherence values than the non kin birds. Thus, within a territory, it was the alpha and the kin birds that formed the core of the group with the non kin birds being much less associated with the other individuals. This was in contrast to the hypothesis, which predicted alpha birds to form the core of the group solely, with kin birds having significantly lower coherence. Interestingly, no effect of habitat type and season was found on the cohesion of the territorial group. Moreover, further evidence of sub-grouping was found even on the kinship level, thus suggesting yet more complex interplay between group cohesion and the group members. All in all, with the non kin birds having low coherence values, the study casts light on the fact that even if individuals are present in a territory, they might not necessarily be a tight unit and as such be unable to fully benefit from group living.
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Effects of a Riverine Dispersal Barrier on Cultural Similarity in Wild Bornean Orangutans (Pongo Pygmaeus Wurmbii)Bastian, Meredith Laurel 28 August 2008 (has links)
<p>The study of culture in wild animals has received wide theoretical and empirical attention, providing preliminary evidence of at least rudimentary culture across a broad range of taxa. However, the majority of previous studies of animal cultural behavior have focused on demonstrating the existence of behavioral variants across study sites, armed only with an assumption that ecological and genetic alternatives are unlikely to sufficiently explain observed geographic variation in behavior. Moreover, previous studies have reported the presence of behavioral variation at the level of the population, without first confirming the presence of such variation in individual repertoires, which could create artificial patterns within or between populations. </p><p>Using more rigorous methods than previous studies, I examined rarely tested alternatives to field-based claims of cultural repertoire variation based on ecological heterogeneity and genetic variation. This dissertation relies on a natural experiment to compare two wild orangutan populations. Sungai Lading, a previously unstudied, high-density population of wild Pongo pygmaeus wurmbii, was compared to Tuanan, a P.p.wurmbii population separated from Sungai Lading by an impassable river barrier, but ranging in a broadly similar habitat. Preliminary genetics results indicate that at least some individuals from both sites cluster in the same mitochondrial subclade and that low levels of gene flow must have occurred between the two sites. Even after applying rigorous controls for variation in sampling intensity for individual orangutans, several differences in innovative behaviors exhibited at each site were identified, many of which occurred in the nesting context.</p><p>The orangutan is a model taxon for such an investigation, because wild populations exhibit a wide range of sociality, which has been linked to opportunities for social learning. Comparisons between the Tuanan and Sungai Lading populations indicated that cultural variants observed at only one site clustered significantly by population, although only dietary differences were unique at both sites. Orangutans at Sungai Lading maintain significantly lower rates of female-female association and lower individual repertoire sizes of putative cultural variants, a result that is consistent with the possibility that the orangutans of Sungai Lading may have reduced opportunities for social learning as a result of severe population compression, which could constrain opportunities for cultural transmission of key innovative behaviors. </p><p>From a broader perspective, the patterns revealed in this study strongly suggest that the last common ancestor of Homo and Pongo shared culturally modified behavior. They further suggest that the extent of cumulative cultural behavior in humans may surpass that of orangutans as a result of lost opportunities for social transmission, owing to varying degrees of limited association among group members.</p> / Dissertation
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