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Pryke, James Stephen. "Conservation of the invertebrate fauna on the Cape Peninsula." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1452.
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Rate, Stephen R., and n/a. "Invertebrate diversity and vegetation heterogeneity : plant-invertebrate relationships in indigenous New Zealand grasslands." University of Otago. Department of Botany, 2005. http://adt.otago.ac.nz./public/adt-NZDU20061025.144447.
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Spatial heterogeneity of the environment, as measured by floral diversity, composition and structure, is known to influence the distribution and diversity of invertebrates. Heterogeneity brought about by anthropogenic disturbance may be a threat to invertebrate diversity. This thesis investigates the impacts of vegetation heterogeneity at a range of scales on the diversity of invertebrate populations in modified high-altitude indigenous grasslands on the Rock and Pillar Range, Central Otago.
Invertebrates were sampled in and on the edges of snow tussock fragments to assess whether species richness increased systematically with fragment area. Invertebrate composition was poorly related to fragment area, plant composition and environmental variables. Taxon richness, abundance and/or diversity for three invertebrate groups increased as fragment area decreased, perhaps reflecting an influx of species from the surrounding matrix. For snow tussock leaf invertebrates in autumn, richness and abundance were at least two times lower in tussocks exposed to the wind than those in the centre of fragments, suggesting selection of habitat may be based on microclimatic characteristics.
Invertebrates were sampled from the bases of tussocks after they were clipped to simulate three levels of vertebrate grazing. Invertebrate community composition differed between sites and sampling dates but was unaffected by clipping treatment. At the higher altitude site invertebrate abundance was 1.45 times greater and Shannon-Wiener diversity (H�) 1.22 times lower than at the lower altitude site. The latter sampling date had higher abundance (2.12 times) and taxon richness (1.14 times) than the earlier date.
Pitfall-trapped invertebrates in cushionfield, herbfield and snow tussock differed in community composition and often by taxon richness, abundance and diversity. Across habitats, plant composition, plant diversity and some environmental variables were correlated with invertebrate variables, but could not be separated from vegetation type.
The invertebrates collected in the course of the study are listed. Four Phyla, eight Classes, 24 orders and over 300 taxa were recorded. Almost all taxa are endemic and many have limited distributions and/or are undescribed. A species list is provided with collection altitude, method and habitat type.
Invertebrate assemblages from sites differing in altitude, vegetation type and level of habitat modification on the Rock and Pillar Range are compared. Sites differed in species composition and rank orders of abundance and richness. At lower elevations, invertebrate richness was at least 25% less, and standardised trap abundance at least 44% less, than that at the highest elevation. Richness and abundance of exotic invertebrates decreased with increasing altitude.
This thesis highlights several points concerning the study of grassland invertebrates and heterogeneity on the Rock and Pillar Range. First, there are differences in invertebrate assemblages at a range of scales. Conserving invertebrate diversity will therefore require altitudinal sequences and different habitat types, including disturbed areas. At high elevations, tussock habitat may be disproportionately important due to its relative rarity. Second, the effects of disturbance on invertebrates were only visible at large spatial scales. Third, there is a paucity of research on New Zealand invertebrates, especially in regard to terrestrial disturbance, which has resulted in a shortfall of biological, distributional, taxonomic and ecological knowledge.
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Rotheray, Timothy Daniel. "Invertebrate grazing during mycelial interactions." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/54800/.
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Saprotrophic cord-forming basidiomycete fungi are major agents of wood decomposition in woodland and support the decomposer food-web. Limited resource availability and the abundance of mycelium in soil leads to competition between fungi. These fungal interactions are aggressive involving reallocation of mycelial biomass, pigment formation, changes in gene expression and enzyme synthesis. Collembola are abundant mycophagous invertebrates in woodlands and affect fungal morphology and growth. Experiments investigated the effects of collembola grazing on fungal interaction progression and the effects of these interactions on collembola behaviour and mortality. In British woodlands, the collembola Folsomia Candida and
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Strachan, Scott. "Invertebrate Resistance to Wetland Drying." Thesis, Strachan, Scott (2016) Invertebrate Resistance to Wetland Drying. PhD thesis, Murdoch University, 2016. https://researchrepository.murdoch.edu.au/id/eprint/29962/.
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In regions with a drying climate, as waterbodies dry out more frequently or for longer, species traits interact with aquatic habitat influencing assemblage composition in wetlands. This thesis aimed to identify potential refuges from increased temperatures and altered water regimes for wetland invertebrates that resist drying using resting stages in the sediment. Using the literature on desiccation-responses by freshwater invertebrates, I reviewed relationships between life histories and the degree of desiccation to which individuals are exposed. Sediment microhabitats that retain moisture were sampled, showing that they could provide microrefuges for invertebrates during seasonal drying. Dry sediment was sampled from two habitats (open water (OW) and fringing trees (FT)) in eight wetlands, sediment properties were measured, and invertebrate emergence from inundated damp and artificially dried sediment were observed. FT sediment was cooler, had higher organic matter content, water saturation potential and different invertebrate assemblage composition. For most species the effect of drying depended on habitat; effects included mortality, reduced abundance and increased abundance. False starts occur when dry wetlands receive brief, unseasonable periods of inundation that trigger invertebrate hatching, but then dry out causing abortive hatching. OW and FT sediments were exposed to false starts in the laboratory. In OW, abortive hatching occurred and new assemblages emerged from egg banks during the next inundation. In FT, invertebrates emerged rapidly and survived drying, continuing to develop into assemblages that did not differ from permanently inundated controls. Overall, this research showed that shallow seasonal wetlands contain refuges from higher temperatures and prolonged drying, explaining the resistance of their fauna to drought. To sustain wetland biodiversity, FT vegetation should be protected and replanted (where necessary) and wetland sediment should be protected from degrading processes such as sedimentation and eutrophication, so that it retains microrefuges.
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Dahl, Joakim Johnson Richard K. Sandin Leonard. "Detection of human-induced stress in streams : comparison of bioassessment approaches using macroinvertebrates /." Upsala : Swedish University of Agricultural Sciences, 2004. http://diss-epsilon.slu.se/archive/00000708/.
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Thesis (doctoral)--Swedish University of Agricultural Sciences, 2004.Thesis documentation sheet inserted. Appendix reproduces three papers and manuscripts co-authored with R.K. Johnson and two papers co-authored with R.K. Johnson and L. Sandin. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.
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Mayoral, Helen. "Particle Size, Critical Shear Stress, and Benthic Invertebrate Distribution and Abundance in a Gravel-bed River of the Southern Appalachians." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/geosciences_theses/31.
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To determine the relationship between the abundance and density of benthic invertebrates, and the critical shear stress of individual grain sizes, a reach along Smith Creek, was divided into ten 2m x 2m quadrants. Within each quadrant, five randomly selected clasts for each grain size ranging from 2.26 to 25.6 cm were cleaned for benthic invertebrates. Wolman pebble counts for each quadrant were also conducted and used to determine the critical Shields stress per grain size fraction from the model given by Wiberg and Smith (1987) that explicitly accounts for particle hiding/sheltering effects in mixed-bed rivers. Particle entrainment values were then compared with estimated bankfull Shields stress values to determine sediment transport potential during bankfull flow. Invertebrate abundance was strongly positively correlated with critical Shields stress up to the 18.0 cm grain size, indicating a preference for certain grain sizes; while density was positively correlated with all grain sizes present.
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Sharp, Koty. "Marine invertebrate-microbial bioactive metabolite symbioses." Diss., Connected to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3190794.
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Thesis (Ph. D.)--University of California, San Diego, 2006.Title from first page of PDF file (viewed Mar. 15, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Pohe, Stephen Robert. "Aquatic invertebrate fauna of Matapouri, Northland." Click here to access this resource online, 2008. http://hdl.handle.net/10292/425.
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A study of the aquatic invertebrate communities from two locations (Location 1 and Location 2) within the Matapouri catchment in Northland, New Zealand, was conducted to assess community structure in differing local-scale habitats. Four data collection methods were utilised generating 33,058 adult or larval invertebrates. The sampling methods comprised benthic kick-sampling, sticky trapping, light trapping, and emergence trapping. For the sticky trapping and light trapping, sampling was carried out at three different sites (Sites 1–3) within each location. The sites were situated within three habitat types; native forest, native forest-fringe, and raupo wetland. Emergence trapping also commenced within the three sites, at both locations, but was discontinued after two months, due to the equipment being destroyed by consecutive flooding events (method described in Appendix 1). Benthic sampling was carried out within the Forest and Forest-fringe habitats. Benthic sampling, sticky trapping, and light trapping were carried out following a monthly schedule between June and November 2005. Conductivity, pH, and water temperature measurements were taken concurrently with benthic sampling on a monthly basis, while water velocity and substrate measurements were taken once to assist in habitat characterisation. Overall, 71 taxa were recorded by benthic sampling over the six month period, with a mean of approximately 30 taxa per site per month. In comparison with similar studies elsewhere in New Zealand, a figure of around 30 taxa per sample was high. The benthic macroinvertebrate fauna at all sites was dominated by Trichoptera (19 taxa), Diptera (16 taxa) and Ephemeroptera (10 taxa). This pattern of diversity is similar to that reported in other New Zealand studies. However, in contrast to previous studies, the leptophlebiid mayfly genus Deleatidium was not numerically dominant over the rest of the community, and other leptophlebiid genera (Acanthophlebia, Atalophlebioides, Mauiulus and Zephlebia) were equally represented, possibly reflecting niche partitioning between the groups. The genus Nesameletus was not recorded at any site, despite being one of the core mayfly species in New Zealand streams. The rare mayfly Isothraulus abditus was recorded at one of the forest locations. There are no published records of this species from Northland. Although acknowledged as another of the core New Zealand benthic taxa, the hydropsychid caddisfly Aoteapsyche was not recorded during the study. However, another hydropsychid, Orthopsyche, was commonly recorded, and these may be filling a similar niche to the Aoteapsyche genus. In contrast to the Trichoptera, Diptera, and Ephemeroptera, the Plecoptera fauna was relatively depauperate, probably reflecting the warmer climate of the region and lack of temperature-buffered spring-fed streams. Surprisingly, Zelandobius, a core New Zealand genus, was absent but is regularly recorded in Northland. A species of conservation interest, Spaniocercoides watti, currently recognised as a Northland endemic, was recorded in low numbers. There were no apparent trends in diversity or abundance of benthic invertebrates over time. Also, there were no significant differences in species diversity between the two locations. However, in many cases, taxa were more abundant at Location 2. This may have been due to steeper gradients at Location 2, and the consequent effects on substrate size and streambed stability, as all other physical factors appeared similar between locations. Although several significant differences of individual benthic taxa were recorded, no broad effect of habitat (sites) on species diversity was observable. However, at Location 2, abundances were significantly higher at Site 3 (Forest) compared to Site 2 (Forest-fringe). The reasons were uncertain, but may be attributed to higher retention of allochthonous organic materials, trapped by in-stream cover and larger substrates. Investigations of adult stages by sticky traps supported benthic results recording community compositions and abundances dominated by Trichoptera and Diptera. Plecoptera were poorly represented. Location 2 recorded higher abundances of taxa, particularly Ephemeroptera and Plecoptera. Investigations of adult stages by light traps however did not produce any statistically significant differences in abundances between sites, between locations, or between sites across locations, and it is believed to be due to limited sampling replication combined with some biases of light trapping. This study indicates that the aquatic invertebrate community at Matapouri is diverse but also reasonably representative. Several rare or uncommon insects inhabit the catchment. It is therefore important that Iwi and the local Landcare Group, who invited and supported this research, together with the Department of Conservation, continue their efforts in protecting these areas. The resident fauna have the capacity to restock areas downstream, which are intended to be improved and restored through sediment control and riparian management.
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Boyd, Sheree. "Benthic invertebrate assemblages and sediment characteristics." Click here to access this resource online, 2009. http://hdl.handle.net/10292/727.
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Cold seep ecosystems in the deep sea are fuelled by chemosynthetic processes based on methane emission to the sediment surface from gas hydrate disassociation, methanogenesis or thermogenic processes. While cold seep ecosystems have been studied in the last three decades worldwide, little is known about New Zealand’s cold seep habitats and associated fauna. A joint German-New Zealand cruise to the Hikurangi Margin in early 2007 enabled biological and sediment sampling to investigate the biological and sedimentological relationships and variability of seeps and their faunal diversity. Multi-disciplinary approaches were employed that included Xray radiography, stratigraphic descriptions, lebensspuren traces analysis, sediment grain size analysis, determination of total organic content, carbonate content and its stable isotopic composition, and analysis of benthic invertebrate assemblages of seep habitats. The results of this study revealed three distinctive habitats and associated fauna based on the sediment characteristics and faunal type. Habitat 1 includes all sites pertaining to Omakere Ridge, a seep-related habitat comprised of layers of very poorly sorted, sandy silt, shell hash and bands of methane-derived authigenic aragonitic carbonate nodules with low total organic content (TOC). Due to the characteristics of the sediments and death assemblages of molluscs, it is inferred that Habitat 1 methane seepage is actively diffusive, waning or dormant. Habitat 2 describes sites that are either non-seep or relic and applies to those at Bear’s Paw and Kaka. Habitat 2 constituted of shell hash overlain with very poorly sandy silt, and low carbonates content and low to medium TOC. Habitat 3 describes non-seep related habitats, and includes all sites of the Wairarapa region and one reference site from Kaka also falls into this category. Sediments for Habitat 3 constituted poorly sorted silt with high TOC and low carbonate content which can be explained by their close proximity to land and converging sea currents. The mineral components of the background siliciclastic sediments for all sites studied originated in the Tertiary mudstone of the East Coast Basin. The characteristics of seep habitats of the Hikurangi Margin were comparable to that of the Northern Hemisphere modern seep counterparts, although the abundance and distributions of seep fauna were low. Results from this research have enhanced our understanding on the spatial and variability of methane fluxes and their affects on the duration of cold seep ecosystems, especially for New Zealand. However, more such studies are essential to increase our understanding of seep sediments and explain disturbance-sediment-benthic invertebrate interactions.
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McClements, Julian Graeme. "Metallochemistry of zinc-replete invertebrate cuticles." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261427.
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Johnson, Kevin Brett. "Predation on planktonic marine invertebrate larvae." Thesis, Thesis (Ph. D.)--University of Oregon, 1998, 1998. http://hdl.handle.net/1794/10086.
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Artal, Mariana Coletty 1987. "Aplicação de teste de toxicidade com o copépodo marinho Nitokra sp. na avaliação de corantes = The use of the marine copepod-Nitokra sp. in the toxicity evaluation of dyes." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267761.
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Orientadores: Gisela de Aragão Umbuzeiro, Guilherme Ribeiro LotufoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia
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Resumo: A produção e uso de corantes representam números relevantes no mundo e no Brasil. Efeitos ecotoxicológicos desses compostos, especialmente frente a organismos estuarinos e marinhos são ainda pouco explorados. Neste estudo avaliou-se a toxicidade dos azo corantes C.I. Disperse Red 1 e C.I. Disperse Red 13 para o copépodo estuarino Nitokra sp. avaliando efeitos adversos como a imobilidade e o sucesso de eclosão dos ovos antes e após tratamento fotoeletroquímico. Os corantes Disperse Red 1 e Disperse Red 13 apresentaram toxicidade para o teste de imobilidade com concentração efetiva CE50(96h) de 0,3 a 2,1 mg.L-1 (n=4) e 1,5 mg.L-1 (n=2), respectivamente. As concentrações que causaram efeitos adversos na taxa de eclosão de ovos foram maiores ou próximas à CE50 de imobilidade, demonstrando que esse endpoint não foi mais sensível como esperado. Testes realizados após o tratamento fotoeletroquímico dos mesmos corantes mostraram que a toxicidade tanto no teste de imobilidade quando no teste de sucesso de eclosão de ovos foi reduzida. Esse tratamento mostra-se promissor para o tratamento desses compostos, porém, cabe ressaltar que a utilização de sal para o tratamento é interferente e causa toxicidade quando descartado ou disposto em ambientes de água doce
Abstract: Production and use of dyes represent relevant numbers in the world and in Brazil. Ecotoxicological effects of these compounds, especially to estuarine and marine organisms are unknown. This study evaluated the toxicity of the azo dye CI Disperse Red 1 and CI Disperse Red 13 to an estuarine copepod Nitokra sp. evaluating adverse effects measured as immobility and egg hatching success before and after photoelectrochemical treatment. Both dyes Disperse Red 1 and Disperse Red 13 were toxic with immobility effective concentration EC50 (96h) in the range of 0.3 to 2.1 mg.L-1 (n= 4) and 1.5 mg.L-1 (n= 2), respectively. The concentrations that caused adverse effects on the success of eggs hatching were higher or close to the EC50 immobility, demonstrating that this is not the most sensitive endpoint as expected. Tests performed after photoelectrochemical treatment showed that the toxicity of both tests was reduced. This treatment shows promise for the treatment of these compounds, however, it is worth noting that the use of salt for treatment is interfering and cause toxicity when discarded or disposed of in freshwater environments
Mestrado
Tecnologia e Inovação
Mestre em Tecnologia
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Figueiredo, Lívia Mara Alves [UNESP]. "Efeitos da terapia fotodinâmica na candidose experimental e resposta imunológica no modelo hospedeiro de Galleria mellonella." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/150842.
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A terapia fotodinâmica (TFD) tem demonstrado ação antimicrobiana sobre as leveduras do gênero Candida, sendo considerada uma técnica promissora para o tratamento de candidose. Recentemente foi relatado que a aplicação de TFD também pode resultar em ativação do sistema imunológico, contribuindo para a melhora da infecção. Assim, o objetivo desse estudo foi avaliar a ação da TFD e da terapia laser sobre a resposta imunológica à candidose experimental utilizando Galleria mellonella como modelo hospedeiro de infecção. Larvas de G. mellonella foram infectadas com diferentes cepas de Candida albicans e, após 30 min, foram tratadas com TFD mediada por azul de metileno e laser diodo emitido em 660 nm. A seguir, as larvas foram incubadas a 37°C por sete dias e analisadas diariamente para determinação da curva de sobrevivência. Para o estudo da resposta imunológica, após os tempos de 3, 6, 18 h da TFD foram realizados testes de determinação da densidade de hemócitos na hemolinfa de G. mellonella. Os dados obtidos na curva de sobrevivência foram avaliados pelo teste de Log-rank (Mantel Cox) e os resultados da análise imunológica por análise de variância ANOVA e teste de Tukey, com significância de 5%. Os resultados obtidos demonstraram que tanto para a cepa ATCC 18804 como para a cepa clínica 17 de C. albicans, a TFD prolongou a sobrevivência das larvas de G. mellonella infectadas por uma dose fúngica letal. Entretanto, houve diferença estatisticamente significante entre os grupos PDT e controle somente com cepa ATCC (p=0,0056). Foi verificado também que a infecção pela cepa ATCC 18804 de C. albicans em G. mellonella levou a uma redução no número de hemócitos na hemolinfa, e o tratamento com TFD e terapia laser conseguiram aumentar o número de hemócitos, mas sem apresentar diferença estatística significante. Foi possível concluir com esse estudo que a TFD bem como a terapia laser influenciaram de maneira positiva na melhora da infecção por C. albicans no modelo de G. mellonella.
Photodynamic therapy (PDT) has demonstrated antimicrobial activity on the yeast of the genus Candida and is considered a promising technique for the treatment of candidiasis. Recently it was reported that the application of PDT may also result in activation of the immune system, contributing to the improvement of the infection. The objective of this study is to evaluate the action of PDT and laser therapy on the immune response to experimental candidiasis using Galleria mellonella as host of the infection. G. mellonella larvae were infected with different Candida albicans strains and, after 30 min were treated with methylene blue-mediated PDT and laser diode emitted at 660 nm. Then, the larvae were incubated at 37° C for seven days and analyzed daily in order to determine the survival curve. For the study of the immunological response, after intervals of 3, 6, 18 h of the PDT, tests were performed to determine the density of hemocytes in the hemolymph of G. mellonella. The data obtained in the survival curve were evaluated by the Log-rank test (Mantel Cox) and the results of the immunological analysis by analysis of variance ANOVA and Tukey test, with significance of 5%. The results demonstrated that for both the ATCC 18804 strain and the C. albicans clinical strain 17, PDT prolonged the survival of the infected G. mellonella larvae by a lethal fungal dose. However, there was a statistically significant difference between the PDT and the control groups only with ATCC strain (p = 0.0056). It was also found that infection by the C. albicans ATCC 18804 strain in G. mellonella led to a reduction in the number of hemocytes in the hemolymph, and the treatment with PDT and laser therapy succeeded in increasing the number of hemocytes but without significant statistical difference . It was possible to conclude from this study that PDT as well as laser therapy positively influenced the improvement of C. albicans infection in the G. mellonella model.
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Arundel, Helen Patricia, and lswan@deakin edu au. "Invertebrate larval dynamics in seasonally closed estuaries." Deakin University. School of Ecology and Environment, 2003. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20061011.142951.
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Estuarine benthic assemblages are often numerically dominated by polychaetes. The limits of these populations are determined by larval, and probably to a lesser extent adult movement. A previous study (Newton 1996), indicated that planktonic polychaete larvae were very abundant over the summer months in the Hopkins River; however, the identification and source of these larvae was not known. Defining the extent of a population, and therefore the likelihood of that population recovering following a perturbation, is crucial for effective estuarine management.
This study investigated both the likely source of the larvae, (i.e. estuarine or marine) and the extent of larval dispersal within and between estuaries by addressing the following questions: Which taxa produced the planktonic larvae? Are these taxa resident estuarine species? Are the larvae of different taxa evenly distributed within the estuary or do physicochemical parameters or other factors influence their abundance? Are the same larvae found in other estuaries along the coast? and Is there exchange of these larval taxa with the marine environment and other estuaries?
Larvae were identified and described by culturing commonly occurring planktonic larvae until adult characteristics appeared. The spionids, Carazziella victoriensis and Prionospio Tatura, numerically dominated the plankton in the Hopkins and the spionid, Orthoprionospio cirriformia was recorded from the Hopkins, Curdies and Gellibrand estuaries. Two spionids, Carazziella sp. and Polydora sp. were identified from tidal waters.
Mouth status and physicochemical conditions (salinity, temperature and dissolved oxygen) were monitored in each estuary. Whereas the Merri and Gellibrand estuaries were predominantly stratified over the sampling period, the Curdies was more often well mixed and the Hopkins varied from well mixed to stratified. The duration of mouth opening and hence the opportunity for larval exchange also varied in each estuary. The Merri River was closed for 13.5% of days over the study period, the Gellibrand River for 18.4%, the Hopkins River for 49% and the Curdies River for 71.0%.
The distributions of larvae at spatial scales of metres, 100s of metres and kilometres were investigated within a single estuary. While the same larvae, C. victoriensis, P. Tatura and bivalve larvae, were found along the length of the Hopkins estuary the abundances varied at different spatial scales suggesting different processes were influencing the distribution of P. Tatura larvae, and C. victoriensis and bivalve larvae.
The distribution of larvae between several estuaries was investigated by monitoring meroplankton at two sites at the mouth of each of the four estuaries approximately monthly (except for winter months). Different meroplanktonic assemblages were found to distinguish each estuary. Further, C. victoriensis and P. Tatura larvae were only recorded in the Hopkins but larvae of the spionid, Orthoprionopio cirriformia were detected in the Hopkins, Curdies and Gellibrand estuaries.
The extent of larval exchange with other estuaries and the marine environment was determined by monitoring tidal waters. Settlement trays were also deployed to determine if larvae were moving into estuaries and settling but not recruiting. P.
tatura larvae were not detected in the tidal waters of any estuary and while C. victoriensis and O. cirriformia were found in both flood and ebb tides there was no evidence of movement of theses taxa to other estuaries. Larvae of the spionids, Carazziella sp. and Polydora sp., were found in tidal waters of each estuary but were rarely detected in the plankton within the estuaries. Neither species was found as an adult in background cores from any estuary, nor with the exception of a few individuals in the Merri, were they detected in settlement trays in any estuary.
I conclude that the source of the larvae of C. victoriensis, P. Tatura and O. cirriformia is estuarine and while C. victoriensis, and O. cirriformia move in and outh of the source estuary in tidal waters there was no evidence for movement to other estuaries. The spionids, Carazziella sp. and Polydora sp were considered to be marine and
while they moved in and out of estuaries in tidal waters they did not usually settle in the estuaries.
The results of this study are a crucial first step in the development of ecological models to better understand dispersal in seasonally closed estuaries that are typical of southern Australia. This study emphasises the unique physicochemical characteristics and biological assemblages within these estuaries and the need for estuarine management to reflect these differences.
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Dodd, Jennifer Ann. "Long-term change in river invertebrate communities." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2959/.
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Finding rules that govern species distribution and coexistence is a fundamental aim of ecological research. The rapidly expanding and increasingly mobile human race is challenging our understanding of some these rules. Using long-term macroinvertebrate data collected from two river systems with contrasting legacies from human activity, this thesis investigates drivers of change in community structure and function, mechanisms underpinning these changes and how these changes affect the accurate assessment of the ecological condition of river systems. The reformation of the river invertebrate communities within the River Clyde system was not predicted by the simple improving measures of water physico-chemistry or life history characteristics of the re-colonising community. This has serious implications for the accurate assessment of river health which is at present largely reliant on the physio-chemical tolerance of macroinvertebrates to indicate prevailing environmental conditions. It is argued that reference condition predictions, like those obtained from the RIVPACS programme, may not be suitable when assessing the ecological health of a river subjected to long-term modification from human activity, like the River Clyde. Significant differences in the stable isotope signatures of resident and colonising populations of Rhyacophila dorsalis (a predatory Trichopteran) provided insight into some mechanisms underlying differences between reforming communities. Trophic position estimates for some colonising populations of R. dorsalis were shown to be lower than expected considering their predatory status and, colonisation patterns were significant in predicting changes in occupied trophic position. The River Endrick is recognised internationally in terms of biodiversity. Over the last 50 years, the diversity of macroinvertebrate fauna of the river has significantly reduced, five species have become locally extinct and there has been a significant change in the distribution of 29 other species. The macroinvertebrate community in the headwater of the river has undergone a dramatic change in structure and function. The contrasting changes to the headwater community and changes in the structure and function of the macroinvertebrate community in the river system require further investigation. This thesis demonstrates the importance of investigating long-term change.
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Roberts, Kimberley Jessica. "Factors limiting invertebrate recovery during stream restoration." Thesis, University of Canterbury. biological science, 2012. http://hdl.handle.net/10092/10373.
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Many stream restoration projects, as part of returning a degraded ecosystem to a healthier state, aim to restore aquatic invertebrate populations. Unfortunately, many attempts only „beautify‟ streams without achieving improvements in biodiversity. Lack of connectivity of a restoration site to a regional species pool may explain some failures. I tested this by collecting larval and adult aquatic insects from an agriculturally impacted Canterbury high country stream to evaluate connectivity of the regional species pool. The stream was surrounded by high-quality habitat in an adjacent National Park. Surrounding streams contained diverse assemblages of aquatic insects, but processes in the environment and limitations of in-stream habitat meant their adults did not always arrive at the target. In addition, oviposition habitat for hydrobiosid caddisflies was added to sections of stream and compared to un-manipulated control sections to test oviposition site limitation. The addition of oviposition habitat led to more hydrobiosid egg masses in comparison to control reaches. However, oviposition was also limited by in-stream habitat conditions, particularly the abundance of fine sediments. Sedimentation is a common pollutant in streams and is linked to decreases in habitat, food resources, and invertebrate populations. Moreover, common restoration methods, such as riparian management, have little success at reversing already high sediment levels, and are therefore insufficient to bring improvements to in-stream communities or sought-after habitat conditions. Therefore, after determining sediment was restricting sensitive invertebrate recovery at Riversdale Stream, by adding patches of high quality habitat I experimentally compared the factorial effects of sediment flushing and channel narrowing on sediment removal. Treatments improved habitat and prompted recovery of sensitive invertebrates, but an interactive effect where both flushing and channel narrowing combined created the most improved habitat conditions and the greatest improvements of invertebrate communities. Thus, while habitat improvements are an important part of restoration, features limiting species recovery such as connectivity and sedimentation, are particularly important.
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Frid, C. L. J. "Community ecology of inter-tidal invertebrate faunas." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380953.
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Vargas, Miguel. "Nutrient response and aging in invertebrate models." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/nutrient-response-and-aging-in-invertebrate-models(3fccf140-7906-4fad-9892-b8957dc44a04).html.
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The diet an organism keeps is crucial in sustaining its health and fitness. The fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans are excellent models for nutritional studies due to their small size, large progeny numbers, quick development, and modifiable laboratory diets. Here I examine these two organisms in order to better understand the complex interrelationship between an animal and its diet. Previous work has shown that in the wild numerous organisms are capable of selecting specific nutrients in a non-random manner in order to maximize fitness. However, the genetic underpinnings driving these nutrient choices remain elusive. Female fruit flies consume higher levels of protein following mating to prepare for the costs of reproduction. I examined the role of S6 Kinase (S6K), a downstream effector of the nutrient-responsive target of rapamycin pathway, in mediating this decision. I demonstrate that neuronal S6K activity and serotonin are involved in regulating protein consumption when allowed to choose nutrients freely as well as following macronutrient deprivation; suggesting that they may play a role in mediating postmating dietary switch and maintaining nutrient balance. Modulating levels of dietary components can have extensive impacts on processes such as development, fecundity, and metabolism in multiple organisms. However, the influence of dietary genetics on the consumer is virtually unknown. I performed a screen feeding single-gene mutants of E. coli to C. elegans and monitored the effects on the insulin-like signalling pathway (ILS). When mutated, genes involved in multiple processes and functions in E. coli enhanced activity of the ILS downstream transcription factor, DAF-16. One mutant strain of E. coli I pursued had a knockout of the cAMP-producing, adenylate cyclase gene. Addition of exogenous cAMP to the diet containing live, metabolically active E. coli rescued all the effects of the mutant on C. elegans; thereby suggesting that bacterial metabolism of dietary cAMP can influence the C. elegans ILS. Collectively, my work demonstrates how the nutrient-sensing pathways of the consumer can shape and be shaped by interactions with its diet. These studies contribute to a better understanding of the consumer-diet relationship, and could help guide future work to investigate the role of diet in disease, quality of life, and longevity.
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Necker, Jasmin. "Einfluß neozoischer Crustaceen auf Invertebrate des Bodenseelitorals." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-39791.
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Marçal, Sandra Francisca [UNESP]. "Efeito de alterações do nível da água do reservatório Salto Grande, usadas para o controle de macrófitas, na estrutura e estabilidade da fauna de invertebrados fitófilos em uma lagoa marginal ao Rio Paranapanema." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/116034.
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Em ambientes aquáticos controlados por barragens, a elevada estabilidade hídrica favorece a proliferação de macrófitas, sendo para seu controle utilizado um manejo por alterações no nível da água. Porém não existem estudos que avaliem o efeito dessa técnica, que gera condições extremas de seca e inundação sobre a fauna de invertebrados fitófilos. O presente trabalho foi realizado durante alterações operacionais do nível da água para controle de macrófitas submersas no reservatório de Salto Grande (SP/PR). O objetivo foi avaliar o efeito dessas alterações sobre a diversidade de invertebrados associados à macrófita Egeria na lagoa Pedra Branca, conectada ao Rio Paranapanema e sob a influência do reservatório. As coletas foram realizadas ao longo de um transecto longitudinal da lagoa, antes do manejo ser iniciado (controle), no 1º, 7º e 11º dias após o rebaixamento (PR), quando a lagoa se desconecta do rio, e 49 dias após o enchimento do reservatório (PE). A hipótese do trabalho de menor diversidade após as alterações do nível da água do reservatório (seca e cheia induzidas) foi avaliada ao nível de toda a fauna e para os táxons de Chironomidae. As alterações do nível da água foram acompanhadas por alterações na estrutura da fauna fitófila, com variação temporal na densidade dos grupos, especialmente de Hexapoda, Mollusca e Protozoa. As mudanças ambientais relacionadas à contração (seca), e conseqüente concentração das macrófitas na área central da lagoa, e ampliação (cheia) das regiões limnética e litorânea geraram uma substituição de grupos dominantes (reduzindo a densidade de Chironomidae e aumentando a de Physa marmorata durante o PR), aumento na riqueza e maior diversidade e equitabilidade no PE. Os distúrbios causaram redução na densidade das três subfamílias de Chironomidae, principalmente de Chironominae, com maior riqueza e dominância em todas as datas ...
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Marçal, Sandra Francisca. "Efeito de alterações do nível da água do reservatório Salto Grande, usadas para o controle de macrófitas, na estrutura e estabilidade da fauna de invertebrados fitófilos em uma lagoa marginal ao Rio Paranapanema /." Botucatu, 2014. http://hdl.handle.net/11449/116034.
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Orientador: Virgínia Sanches UiedaBanca: Ana Lúcia Brandimarte
Banca: Marcelo Luiz Martins Pompêo
Banca: Alaíde Aparecida Fonseca Gessner
Banca: Marcos Gomes Nogueira
Resumo: Em ambientes aquáticos controlados por barragens, a elevada estabilidade hídrica favorece a proliferação de macrófitas, sendo para seu controle utilizado um manejo por alterações no nível da água. Porém não existem estudos que avaliem o efeito dessa técnica, que gera condições extremas de seca e inundação sobre a fauna de invertebrados fitófilos. O presente trabalho foi realizado durante alterações operacionais do nível da água para controle de macrófitas submersas no reservatório de Salto Grande (SP/PR). O objetivo foi avaliar o efeito dessas alterações sobre a diversidade de invertebrados associados à macrófita Egeria na lagoa Pedra Branca, conectada ao Rio Paranapanema e sob a influência do reservatório. As coletas foram realizadas ao longo de um transecto longitudinal da lagoa, antes do manejo ser iniciado (controle), no 1º, 7º e 11º dias após o rebaixamento (PR), quando a lagoa se desconecta do rio, e 49 dias após o enchimento do reservatório (PE). A hipótese do trabalho de menor diversidade após as alterações do nível da água do reservatório (seca e cheia induzidas) foi avaliada ao nível de toda a fauna e para os táxons de Chironomidae. As alterações do nível da água foram acompanhadas por alterações na estrutura da fauna fitófila, com variação temporal na densidade dos grupos, especialmente de Hexapoda, Mollusca e Protozoa. As mudanças ambientais relacionadas à contração (seca), e conseqüente concentração das macrófitas na área central da lagoa, e ampliação (cheia) das regiões limnética e litorânea geraram uma substituição de grupos dominantes (reduzindo a densidade de Chironomidae e aumentando a de Physa marmorata durante o PR), aumento na riqueza e maior diversidade e equitabilidade no PE. Os distúrbios causaram redução na densidade das três subfamílias de Chironomidae, principalmente de Chironominae, com maior riqueza e dominância em todas as datas ...
Abstract: Not available
Doutor
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Uys, Charmaine Janet. "The impact of pine plantations and alien invertebrates on native forest and fynbos invertebrate communities in Table Mountain National Park." Doctoral thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/6888.
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While the Cape Peninsula (South Africa) is renowned for its exceptional plant and invertebrate diversity and endemism, extensive alien plant invasions and exotic pine plantations threaten and reduce native species richness. This study frames invasion ecology theory in a conservation context, and examines the impact of planting and felling pine on litter invertebrate communities, by comparing invertebrate diversity between pine plantations and native vegetation. Impacts of the worst invasive alien invertebrate (Argentine ant, Linepithema humile) and other alien invertebrate species are investigated. This is one of the first attempts to inventory and quantify impacts of non-ant alien invertebrates in Table Mountain National Park. The entire ground-dwelling invertebrate community was sampled at 31 sites in summer 2008/2009, using soil cores, leaf litter samples, pitfall traps, sugar-baited ant traps and decayed logs. A total of 112 404 individuals, representing 728 species (10 classes and 38 orders), including nine Cape Peninsula endemic and 19 alien species, was collected. Pine plantations supported lower species richness and abundance, and different community assemblages, compared to Afrotemperate forest, but similar species richness to fynbos. This supports previous local studies and global trends. Pine plantations shared fewer species with fynbos than forest, and negatively affect fynbos-specialist invertebrates, because afforestation reduced available fynbos habitat. Alien species richness was similar across habitats. Argentine ants, like most other alien species identified, were present in all habitats. The impact of Argentine ant invasion on native ant communities was evaluated using species richness and community composition analyses, species co-occurrence patterns (C-score), and the functional group approach. The comparative approach adopted provided no evidence for displacement, impoverishment, or community disassembly. No clear impacts of the 18 non-ant alien species on the abundance, species richness, or community composition of corresponding native taxa were detected. Disturbance history offers a more parsimonious explanation for the trends observed, particularly in fynbos. However, carnivorous molluscs require careful monitoring, given their abundance and known impacts elsewhere. Using a reiterative process and IndVal, two ant species (Pheidole capensis and Camponotus bertolinii) were selected as ecological indicators of restoration progress in fynbos following clear-felling of pine. Ants similarly have application for monitoring in other Mediterranean-type ecosystems impacted by invasive pines.
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Thomas, Jessica Ann. "The Tempo and Mode of Invertebrate Molecular Evolution." Thesis, University of Sussex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487903.
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Kirby, Alan. "Invertebrate interactions with red grouse (Lagopus lagopus scoticus)." Thesis, University of Stirling, 2003. http://hdl.handle.net/1893/26691.
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Ramsell, Joanne. "The influence of plant quality on invertebrate herbivory." Thesis, Lancaster University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279586.
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Guven, Kemal. "Invertebrate stress responses as molecular biomarkers in ecotoxicology." Thesis, University of Nottingham, 1994. http://eprints.nottingham.ac.uk/11376/.
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All organisms studied so far respond to heat shock by inducing the synthesis of a number of proteins called heat shock proteins(LISPs). This universal response can also be induced by a variety of stressors, including heavy metal ions and organic and organo-metallic compounds. As a result, the stress response has recently attracted the attention of ecotoxicologists for use in environmental biomonitoring. In the present study, we have investigated the stress responses of two different organisms ; namely the free-living soil nematode Caenorhiabdities elegans(both wild-type and transgenic strains) and the freshwater crustacea Asellus aquazicus. We have also explored the possible use of these model systems in environmental monitoring using different techniques which include metabolic labelling with subsequent one-dimensional electrophoresis and autoradiography, and one- or two-dimensional western blotting using antibodies specific to stress protein 70. The study with A. aquaticus shows that this organism exhibits a classical stress response. The exposure of asellids to heat shock-treatment (26°C ; 13°C above the standard maintenance temperature) or to sublethal concentrations of metal ions (Cd++ and Cu++) resulted in the induction of at least 5 putative HSPs which belong to several major HSP families (HSP100, HSP90 and possibly HSP60). An increase in the synthesis of smaller sizes of polypeptides (25-35 kD) should be also noted. Moreover, the time-course of heat versus heavy metal stress-response in this organism suggests that the pattern of stress-protein synthesis changes considerably with increasing exposure time ; notably the response to heat is more transient than that to heavy metals. However, HSP70 does not appear to be the major stress protein induced in this organism. The presence of low molecular weight (LMW) proteins which react with anti-HSP70 antibodies and the apparent deficiency of classical 70 kD stress proteins in A. aquaticus, both suggest that HSP70s in this organism are for some reason prone to degradation. In the nematode C .elegans, shifting the culture temperature from 20°C to 34°C induces the synthesis of a set of HSPs corresponding to the HSP90, HSP70 and small HSP families. There are at least nine members of the hsp7O multigene family in C. elegans ; some members are expressed constitutively while others are stress inducible. W e have studied the effects of heat and heavy metal (cadmium) stress on the expression patterns of the HSP70 protein family in the nematodes by one- and two-dimensional Western blotting using a monoclonal anti-HSP70 antibody that recognises a conserved epitope shared by most HSP70 family members. Constitutive C. elegans HSP70s (expressed at 20°C) are almost undetectable on one-dimensional immunoblots, but chemiluminescent probing of two-dimensional blots reveals a complex pattern of several HSP70s pots .Mild heats hock at 31° C induces a doublet HSP70 band on one-dimensional blots, of which the heavier component (75 kD) is more prominent than the lighter (73 kD). On two-dimensional blots, this pattern is shown to be more complex with a prominent 75 kD spot newly induced and several other spots intensified. Severe heat shock at 34°C strongly induces both 75 and 73 kD bands on one-dimensional blots; two dimensional analysis reveals a series of novel and/or elevated 73 and 75 kD spots. Treatment with cadmium( 16 ppm) at 31° C gives a different pattern of spots as compared with 31 °C alone ; several spots show enhanced while some are newly expressed, and not all of these are present at 34°C. These results indicate that related members of the HSP70 protein family in C. elegans are independently regulated in response to different forms of stress. The possible significance of these findings is discussed in relation to the possible use of stress responses s environmental biomonitors. We have also utilised a stress-inducible C. elegans strain (CB4027) for monitoring environmental contamination. This transgenic strain carries integrated copies of the Drosophila hsp70 promoter fused to an E.coli lacZ reporter gene. When exposed to heat shock or to several environmentally relevant stressors, the transgenic strain expresses the reporter product, 3-galactosidase, which can easily be quantified or localised in situ in stained worms or on Western blots (apparently enzymatically active as a 170 kD form). We have exposed transgenic worms to a variety of toxicants at an elevated temperature (32°C) just below that required for heat shock (34°C), in order to obtain optimal transgene induction. Exposure of nematodes to several heavy metals (e. g. Cd+, Hg++, Zn+, Sn++, Mn++ and Ag+), organometallic toxicants (tributyltin) or organic pollutants (lindane) induces ß-galactosidase expression in a dose-dependent manner. Cadmium is found to be by far the strongest inducer of transgene activity amongst the agents tested, although tributyltin is an effective inducer at ppb levels. The effects of mixtures of divalent metal ions (Cd++/Ca++, Cd++/Zn++ and Cd++/Hg++) on ß-galactosidase expression have been also investigated. All three divalent ions tested in combination with cadmium significantly inhibit cadmium-induced transgene activity in comparison to cadmium alone. In the case of Cd++/C++ mixtures, a marked inhibition of Cd++ accumulation by worm tissues has also been demonstrated, directly related to the Ca++ concentration. These effects may represent competition for metal-ion uptake through calcium channels. Our results show that this transgenic system works well within strictly defined assay conditions, and can detect clear responses over a 7h exposure period to environmentally relevant toxicants at sublethal concentrations well below the 24 or 48h LCSO values. However, there is a need for careful characterisation and containment of any transgenic organism if it is to be used as environmental monitoring tool.
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Chan, Ying-shan, and 陳映姗. "Effects of silver nanoparticles on marine invertebrate larvae." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/208175.
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Silver nanoparticles (AgNPs) have gained much popularity in consumer products due to their strong antimicrobial ability. The majority of research concerning the biological effects of AgNPs has been limited to humans, mammals and freshwater organisms. Marine organisms, especially invertebrates, have been studied to a lesser extent. The objective of this thesis was to understand the effects of AgNPs on the marine benthic invertebrates. Specifically, we focused on the acute and sub-lethal toxicity of two AgNPs (Oleic acid coated AgNP (OAgNP) and Polyvinylpyrrolidone coated AgNP (PAgNP)) on marine invertebrate larvae across three phyla (i.e. the barnacle Balanus amphitrite, the limpet Crepidula onyx and the polychaete Hydroides elegans) in terms of mortality, growth, development and metamorphosis. Bioaccumulation and biodistribution of silver, as well as apoptosis induction were also investigated. To distinguish the toxic effects derived from nano-silver and aqueous form of silver, larvae were also exposed to silver nitrate (SN) in parallel.
In the acute toxicity test, larvae were exposed to OAgNPs and PAgNPs for 48 hours, and the concentration leading to 10 % mortality (〖LC〗_10) were determined and compared. The results indicated that B. amphitrite and H. elegans were more sensitive to OAgNPs (〖LC〗_10: 0.138 and 2.63 × 〖10〗^(-4) μμg L-1, respectively) than PAgNPs (〖LC〗_10: 0.502 and 0.317 μμg L^(-1), respectively). In contrast, C. onyx was more susceptible to PAgNPs (LC10: 38.5 μμg L^(-1)) than OAgNPs (〖LC〗_10: 467 μμg L^(-1)). Among the three taxonomic groups, C. onyx was most tolerant of AgNPs, following by B. amphitrite and H. elegans.
The sub-lethal effect of AgNPs resulted in a significant retardation in growth and development, and the reduction of settlement rate of all three species tested. In particular, the settlement rate of H. elegans was significantly lower in AgNPs treatment than in SN treatment, suggesting that toxicity of AgNPs might not be solely evoked by the release of silver ion (Ag+) into the test solution. The three species took up and accumulated silver efficiently from all forms. Importantly, AgNP aggregates were found along the digestive tract of C. onyx and the TEM images further confirmed that AgNPs were able to move across the plasma membrane. In addition, TUNEL assay indicated that AgNPs could induce apoptosis in B. amphitrite and C. onyx. In view of the very low number of detected apoptotic cells and the random occurrence of cell death found, AgNP-induced apoptosis does not appear to be the major toxicity mechanism in causing delayed growth and settlement failure. Unlike the results revealed from acute toxicity test, surface coatings did not affect the sub-lethal toxicity of AgNPs.
This research clearly demonstrated that AgNPs exerted toxic effects in a speciesspecific manner, and long-term exposure of AgNPs might allow bioaccumulation of silver, induce apoptosis, and affect growth, development and recruitment of marine invertebrates. This study also highlighted the possibility that toxicity of AgNPs might be mediated through toxic Ag+ as well as the novel modalities of AgNPs.published_or_final_version
Biological Sciences
Master
Master of Philosophy
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Beugly, Jayson S. "Fish and invertebrate communities in agricultural headwater streams." Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1391472.
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Agricultural practices may influence stream biological communities by removing riparian vegetation and modifying stream channel morphology, both which may reduce water retention time. I collected benthic invertebrates and fishes in seven headwater agriculturally-influenced streams in central Indiana, to quantify controls on invertebrate and fish community assemblage variation. Invertebrates were collected at 14 sites and fish were collected at 12 sites in Buck Creek watershed. The abundances of invertebrates and fishes were analyzed in Detrended Correspondence Analyses (DCA) in PC-ORD software and correlated with abiotic and biotic factors. The sites located in close proximity to Buck Creek have increased stability of biotic (fish assemblages) and abiotic (flow and water depth) factors. Abundances of invertebrates of headwater streams in east-central Indiana agricultural landscapes are influenced by distance between sites, distance to Buck Creek, and presence of fish species. Abundances of fishes were correlated with water quality and distance to Buck Creek.Department of Biology
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Andersson, Sandra. "The effects of artificial illumination on invertebrate drift." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-35320.
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Cariss, Helen. "Enhancement of invertebrate assemblages in conifer forest streams." Thesis, Manchester Metropolitan University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284877.
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A'Bear, Andrew Donald. "Climate change, fungus-invertebrate interactions and ecosystem processes." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/58513/.
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Saprotrophic fungi are the main agents of primary decomposition and nutrient cycling in woodland ecosystems. Powerful enzymatic capabilities enable then to break down the most recalcitrant components of wood and leaf litter, such as lignin and cellulose. Nutrients are retained by dynamic networks of mycelium, which are vulnerable to grazing by soil invertebrates. The studies reported in this thesis employed laboratory microcosm, mesocosm and field manipulations to further mechanistic understanding of climate change effects on basidiomycete fungal-dominated woodland decomposer community dynamics and ecosystem processes. Increased mycelial growth at elevated temperature can be prevented by collembola grazing in soil microcosms. The strength of this top-down effect varied with fungal palatability, which had a bottom-up effect on collembola populations and their responses to warming. A mesocosm multispecies collembola population was more strongly regulated by the bottom-up effect of inoculation with cord-forming fungi than climate change (warming, in combination with soil wetting or drying). Collembola can graze fungal cords, but thickness and chemical defences make them less palatable than soil microfungi, which are outcompeted by basidiomycete mycelia. In the absence of fungal biomass limitation by collembola, abiotic conditions regulated microbial community functioning. Warming stimulated fungal-mediated wood decomposition, particularly in drier soils. Moisture was the most important determinant of enzyme activity and displayed an interaction with temperature analogous to that for wood decay. Macro-invertebrates, such as woodlice, are better able to exploit nutritious, but thick and defensive, fungal cords. The consequences of macro-invertebrate grazing for fungal-dominated microbial community function were tested in a field manipulation of woodlouse (Oniscus asellus, Isopoda) population densities, predicted to increase due to climate warming. This provides the first evidence for bottom-up effects of fungal palatability on woodlouse populations. Body lipid analysis revealed fungi as a major component of the generalist woodlouse diet. Despite low population densities at the site, altered O. asellus abundance influenced aspects of microbial community functioning. The importance of biotic effects on decomposition may be more heterogeneous than abiotic influences, depending on microbial community dominance and the abundance of key macro-invertebrate taxa.
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Winters, Amanda. "Effects of Warming and Predation on Invertebrate Activity." Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1499357799174464.
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Stone, Marisa J. "Invertebrate-mediated ecosystem functioning during deforestation and reforestation." Thesis, Griffith University, 2020. http://hdl.handle.net/10072/397590.
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Conversion of forests to pasture has been extensive throughout the tropics and subtropics, and these forests continue to experience deforestation at high levels. Such clearing can alter plant-animal dynamics and thereby degrade ecosystem functioning. It is often assumed that re-establishment of vegetation will recover forest-like communities of animals such as invertebrates, together with the roles they play in important ecosystem processes. However, there has so far been little empirical evidence to support this. This thesis investigated the impact of deforestation on invertebrate-mediated ecosystem functioning, and its recovery during regeneration of rainforests on former pasture. Specifically, it focused on two key ecosystem processes which underly forest regeneration dynamics, while also comparing two different reforestation pathways. The two processes were leaf litter decomposition rates and insect seedling herbivory. For decomposition, functional associations with decomposer invertebrates as well as vegetation structure and floristics were also investigated. Both these ecosystem processes were examined across 25 sites representing different phases of rainforest deforestation and subsequent reforestation.
The study area was the Numinbah Conservation Area and surrounds on the Gold Coast Hinterland, in the eastern Australian subtropics. Here the local council had begun restoration management on disused pasture approximately 10 years prior to the beginning of this thesis. Five study sites were placed in each of five vegetation types, consisting of two reference states of grazed pasture and old-growth rainforest (to represent the deforestation process and to indicate the target of restoration), together with three types of regenerating vegetation: unassisted woody regrowth aged 20-50 years on former pasture, and assisted regeneration aged 1-4 and 5-11 years after human interventions that aimed to accelerate natural regeneration within previously-unassisted regrowth.
To measure decomposition rates (mass loss % per unit time), open and closed mesh litter bags (to exclude macro-invertebrates >1mm length and width) were deployed across the 25 sites filled with leaves of five local tree species for five and eight months. Most of the decomposition had already occurred by five months, as only a further 3% decomposition occurred in the following three months. Macro-invertebrates did contribute to mass loss, but their exclusion from litter bags only marginally decreased decomposition rates, by 3%. Decomposer community composition at a broad taxonomic level differed strongly between pasture and all other vegetation types. Decomposition rates in open bags were about 50% slower in pasture than in old-growth forest, but had recovered to 83% of old-growth values in all types of regenerating vegetation. Samples of decomposer invertebrates were also collected from ground litter within each of the 25 sites. Abundances of macro- and meso-decomposer invertebrates decreased by 95% and 77% respectively in pasture. Abundances of invertebrate decomposers had recovered to old-growth forest levels in all restoration types of recovering vegetation. However, decomposition rates in open-bags were significantly correlated (across sites) with abundances of both macro- and meso-decomposers, most strongly so for meso-decomposers.
Investigations were also made into how vegetation structure and floristic composition of trees differed among the five vegetation types, and associations between these differences and variations in decomposition differed among sites. The main changes in vegetation were: (1) after 5-10 years of interventions to assist natural regeneration, abundance and species richness of trees (>1 m height) with stem sizes <10 cm dbh and 10-50 cm dbh had recovered, (2) also after 5-10 years of interventions to assist natural regeneration, canopy cover had recovered, and (3) tree species composition (all stem sizes) differed between old-growth and regenerating areas, and between unassisted and assisted natural regeneration (respectively dominated by Lantana camara and various pioneer tree species). There was a large step-change in decomposition rates associated with the transition from pasture to regenerating woody vegetation (33% difference), during which canopy cover (from 0% in pasture to 51-69% in regenerating areas) was both most important for describing differences in vegetation, and a good predictor of decomposition rates. A second step-change of decomposition rates was associated with the transition from regenerating woody vegetation (of all types) to old-growth rainforest (17% difference), during which both canopy cover and tree species composition were most important in describing differences in vegetation. However, canopy cover no longer explained variation in decomposition rates among woody regeneration areas and old-growth rainforest; in these cases, tree species composition was the better predictor.
To investigate seedling herbivory, 200 seedlings of two tree species (100 Glochidion ferdinandi and 100 Toona ciliata) were planted across the 25 sites (eight seedlings of each species per site), and leaf area loss (%) and the types of damage were recorded on immature and mature tagged leaves at four times during seven months. The percentage of leaf area lost due to herbivory accumulated in leaves over time for both species and at seven months was 25% and 37% respectively for G. ferdinandi and T. ciliata. There was no difference in the accumulated amount of herbivory between leaves which were immature or mature when first tagged, and there was no effect of vegetation type on herbivory rates in either species. Leaf start age (immature vs mature) also had no effect on the type of herbivory. Vegetation type did have an effect on the type of herbivory, which was mostly driven by differences in pasture, but more so for T. ciliata than G. ferdinandi. However, the damage types were driven by relatively uncommon types of leaf damage. On the other hand, the damage types which occurred most frequently, and caused the greatest amount of damage, occurred consistently throughout all the vegetation types. Most leaf damage was caused by various types of Lepidoptera larvae.
The results of this study showed that conversion of forest to pasture halved decomposition rates but had little effect on seedling herbivory. The reduction in decomposition was associated with an effect of deforestation on important drivers of decomposition rates, including the abundance and composition of decomposer invertebrates, and amount and composition of canopy cover. During regeneration, decomposition rates partially recovered, associated with a full recovery of decomposer invertebrates. However, a full recovery of decomposition rates was likely restricted by a difference in litter layer quality, because tree species composition in old-growth rainforest differed greatly from that in all types of regenerating vegetation. Seedling herbivory was unaffected by deforestation, most likely because adults of the most common type of insect herbivores, Lepidoptera, can detect suitable host plants through the volatile chemicals that they emit, and because they are also capable of flying the distances (<2 km) from source populations. Since seedling herbivory was little effected by deforestation, the concept of recovery during regeneration did not apply, and neither did it change during regeneration.
Overall, both types of invertebrate-mediated ecosystem functioning were resilient to deforestation as any decline in functioning quickly recovered (or partially recovered) during reforestation. These results occurred irrespective of whether interventions to assist natural regeneration were used. Decomposition rates had already substantially recovered before the woody regrowth reached 20-50 years of age, and seedling herbivory was unaffected by the types of vegetation within which the host plant was located. Therefore, it is unlikely that any types of interventions used to assist natural regeneration would have a significant effect on invertebrate-mediated ecosystem functioning subsequent to regeneration of regrowth aged 20-50 years. Further, the recovery of the invertebrate communities was likely facilitated by the proximity to an old-growth rainforest source, together with extensive surrounding forest cover of several types. Therefore, a reduced supply of source invertebrate populations in the landscapes that surround regenerating areas may, in poorly forested regions, lead to lower functional resilience. Nevertheless, in moderately forested landscapes (such as in the present study), simply removing barriers to natural regeneration may be all that is required to achieve successful recovery of invertebrate-mediated ecosystem functioning during regeneration.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
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Berglund, Hanna. "Biological Soil Invertebrate Activity in a Tropical Rainforest : A comparison of soil invertebrate activity in two tropical rain forests in Borneo." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-411109.
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Logging of tropical forests is increasing worldwide. Logging alters the forest conditions such as temperature, soil water content and litter input into the soil. This study explored how soil invertebrate activity in Borneo differs between pristine forests and two secondary forests, with 10 and 40 years of recovery time since the last logging. To measure the soil fauna feeding activity, the bait lamina stick method was applied. The study was conducted in Sabah, Malaysian Borneo, during April and May 2019. 33 forest plots were examined with ten lamina sticks placed in each of the three replicas per forest plot. The sticks were kept in the soil for four weeks before being removed. Upon removal, the soil invertebrate activity was determined by assessing how many holes of the bait lamina sticks were eaten and at what depth. The activity was related to the above-ground carbon density (ACD, a density measure for amount of above-ground carbon), as well as depth-specific activity in the different plots. Moreover, further relationships with the invertebrate activity and environmental conditions such as cumulative throughfall during the study time as well as the soil water content were studied. The results showed that the soil activity slightly decreased with increased ACD, but no statistical significance was found. This study also suggests that the activity was higher in the upper 0-5cm of the soil than in the lower 5-10 cm. Lastly, the results showed that the activity was highest in the forest with the shortest recovery time (10 years). This implies that it might be possible to regain the original soil activity since the activity of the 40-year-old forest was closer to the pristine forest than that of the 10- year-old forest.
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Bowman, Sarah R. "Utilizing soil characteristics, tissue residues, invertebrate exposures and invertebrate community analyses to evaluate a lead-contaminated site: A shooting range case study." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437585549.
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DeBlois, Elisabeth M. "Invertebrate predation on the benthic eggs of marine fish." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39387.
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The character and magnitude of predation by Calliopius laeviusculus on the intertidal eggs of capelin (Mallotus villosus) were examined. Average endobenthic densities at Bryant's Cove (NFLD) in 1988 for both amphipods and capelin eggs during capelin egg development (June 17-August 8) were 0.78 amphipods cm$ sp{-2}$ and 62 eggs cm$ sp{-3}$ (750 cm$ sp{-2}$) respectively. At this average capelin egg density, laboratory results suggest that, on a daily basis, only gut capacity and clearance time limit amphipod predation on eggs. In situ, C. laeviusculus biomass closely tracked capelin egg biomass indicating that reproductive cues operating for both capelin and amphipods may be linked. In 1988, ca. 50% of the annual production of C. laeviusculus resulted from predation on capelin eggs. Given the bioenergetic demands of C. laeviusculus and the annual variation in capelin spawning effort, the temporal overlap between capelin eggs and high amphipod biomass could result in predation mortalities ranging from ca. 15-30% of the total capelin egg deposition.
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Lancaster, Jill. "Invertebrate predation and community structure in an acid stream." Thesis, Queen Mary, University of London, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284801.
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Ledger, Mark Edward. "Invertebrate grazing of biofilm in streams of contrasting pH." Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266219.
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Digby, Bruce. "Invertebrate production within various habitats of a braided river." Thesis, University of Canterbury. Environmental Science, 1999. http://hdl.handle.net/10092/7036.
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Seepage streams within "flood overflow" channels are important microhabitats within braided rivers. They are important foraging zones for wading birds and may contribute to the ability of the invertebrate community to recover from disturbance. Production of dominant invertebrates was estimated along a three kilometre study reach of the
Rakaia River for various channel types ranging from seepage stream microhabitats within secondary channels to the largest braids in the central river bed. The seepage and spring stream microhabitats received varying exposure to elevated summer flows, freshes, and were inundated by flows of greater than approximately 200 cumecs. Four quadrats were randomly located within 10 metre sampling transects in riffles of seepage and spring stream microhabitat in addition to minor and major braids.
Riffles were sampled at six week intervals from October 1997 to August 1998, with no riffle sampled more than once. Production was estimated using the size frequency method. Seepage stream microhabitats were the most productive sites examined. Production was estimated to be 10.3 g DW m-² yr-¹ for a perennial seepage stream, 3.2 g m-² yr-¹ for a baseflow seepage stream, 1.0 g DW m-² yr-¹ for a baseflow spring stream, and 0.5 g DW m-² yr-¹ and 0.6 g DW m-² yr-¹ respectively for the minor and major braids. The two types of seepage stream had significantly greater production than the minor and major braids. Invertebrate production is likely to be affected by gradients of disturbance, temperature, algal abundance, and organic matter retention. Frequent and unpredictable flooding probably restricts production in the minor and major braids but helps maintain structure of seepage and spring stream microhabitat in secondary "flood overflow" channels.
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Wilmes, Miriam [Verfasser]. "Antibiotic mechanisms of invertebrate and mammalian defensins / Miriam Wilmes." Bonn : Universitäts- und Landesbibliothek Bonn, 2013. http://d-nb.info/1044868546/34.
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Elliott, M. M. "Some effects of invertebrate herbivores on deciduous woodland regeneration." Thesis, University of East Anglia, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355345.
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Ashley, Claire M. "Toxicology of dioxin in an invertebrate, Pacifastacus leniusculus (Dana)." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283656.
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Thomas, Matthew Brian. "Manipulation of overwintering habitats for invertebrate predators on farmland." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316454.
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Pretty, James L. "Detritus retention and invertebrate communities in forestry impacted streams." Thesis, Manchester Metropolitan University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323849.
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Wheeler, Jeanette Danielle. "Behavioral responses of invertebrate larvae to water column cues." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103337.
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Thesis: Ph. D., Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Department of Biology; and the Woods Hole Oceanographic Institution), 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 139-150).
Many benthic marine invertebrates have two-phase life histories, relying on planktonic larval stages for dispersal and exchange of individuals between adult populations. Historically, larvae were considered passive drifters in prevailing ocean currents. More recently, however, the paradigm has shifted toward active larval behavior mediating transport in the water column. Larvae in the plankton encounter a variety of physical, chemical, and biological cues, and their behavioral responses to these cues may directly impact transport, survival, settlement, and successful recruitment. In this thesis, I investigated the effects of turbulence, light, and conspecific adult exudates on larval swimming behavior. I focused on two invertebrate species of distinct morphologies: the purple urchin Arbacia punctulata, which was studied in pre-settlement planktonic stages, and the Eastern oyster Crassostrea virginica, which was studied in the competent-to-settle larval stage. From this work, I developed a conceptual framework within which larval behavior is understood as being driven simultaneously by external environmental cues and by larval age. As no a priori theory for larval behavior is derivable from first principles, it is only through experimental work that we are able to access behaviors and tie them back to specific environmental triggers. In this work, I studied the behavioral responses of larvae at the individual level, but those dynamics are likely playing out at larger scales in the ocean, impacting population connectivity, community structure, and resilience. In this way, my work represents progress in understanding how the ocean environment and larval behavior couple to influence marine ecological processes.
by Jeanette Danielle Wheeler.
Ph. D.
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Edwards, Francois K. "Fish presence and the ecology of stream invertebrate predators." Thesis, University of Edinburgh, 2005. http://hdl.handle.net/1842/14773.
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This thesis describes the ecology of invertebrate predators (Plecoptera and Trichoptera) across steams, some without fish. Focusing primarily on stoneflies of the families Perlidae and Perlodidae, I studied the density and diversity of predators and the invertebrate prey, predator diet, size-mass relationships and microhabitat use. The abundance of invertebrate predators varied across streams and seasons but numbers of predatory invertebrates did not differ with fish presence. Only the smallest species of invertebrate predator was more abundant in substrate complexes in streams with fish. Overall biomass of invertebrate predators was lower in streams with fish, because the size-class distributions of some species were biased towards small individuals. The size-mass relationships and pre-emergent weights of all predators, except the Perlidae, varied across sites, but there was no clear relationship between condition and fish presence/absence. Invertebrate predators were mainly carnivorous in fishless sites, but in some species diet broadened with fish presence to include more algae. I hypothesise that the fixed nocturnal habit of Perlidae, permitted by their slower growth, accounted for the similarity in abundance, size, condition and diet across streams. Nocturnal activity and the coarse stony substrate which provided abundant refugia, minimised any effect of fish. By contrast, Perlodidae and other predators have shorter life cycles, forage by day and night, and have greater growth requirements, accounting for the greater variability in size and condition across streams. Though these species should incur greater exposure to fish, the coarse substrate may provide foraging space free from predation risk, thus minimising any effects of fish. For stream invertebrate predators, direct predation effects of fish appear to be minimal and principal effects may be sublethal, indirect, and prey mediated.
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Astley, Katrina Nicola. "The ecotoxicological assessment of complex effluents using invertebrate biomarkers." Thesis, University of Plymouth, 1998. http://hdl.handle.net/10026.1/2024.
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A suite of biomarkers was developed using the crab Carcinus maenas and the mussel Mytilus edulis as test organisms. The ability of the biomarkers to differentiate amongst the major toxic components and to indicate the concentration of chemical mixtures was evaluated in the laboratory. Biomarkers were also applied in a field trial and their potential to monitor environmental water quality in a chemically contaminated estuary investigated. The results from the biomarker assays were compared with and validated against two commonly used toxicity tests (Tisbe battagliai LC-50, and Microtox®). Novel methods for recognising patterns of biomarker responses were developed and assessed. The most sensitive and reliable biomarker assays investigated were neutral red retention time in crabs and mussels and heart rate and glutathione-S-transferase activity in crabs. Effects were observed at environmentally realistic concentrations; for example lysosomal enlargement was observed in mussels exposed to a complex mixture containing chemicals at environmental quality standard concentrations. Exposure concentrations required to illicit biomarker responses were similar to toxicity test EC-50 values. The ease of interpretation and clarity of the results was enhanced when data from suites of biomarkers were pooled and analysed using multivariate statistical techniques (multidimensional scaling and cluster analysis). Multivariate analysis differentiated amongst mixtures containing solely organic chemicals, metals and metal and organic chemical mixtures. Exposure response relationships to complex mixtures were established for some of the individual biomarkers tested (crab heart rate and gill metallothionein) and also for suites of biomarkers when multivariate analysis was carried out. In the field biomarkers, in both transplanted and indigenous animals, were able to differentiate between clean and contaminated sites and indicate a pollution gradient along the Tees Estuary. This was not achieved using toxicity tests. The results were displayed clearly using multivariate analysis, enhancing the power of biomarkers as monitoring tools.
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Kenly, Travonya L. "Variability in Invertebrate Trophic Networks along Stream Nutrient Gradients." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1525715627495345.
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Cevallos, Randal Curtis. "Manipulation of the invertebrate host cell machinery by dicistroviruses /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Filbert, Randall B. "Is Rainbow Trout Condition Influenced By Invertebrate-Drift Density?" DigitalCommons@USU, 1991. https://digitalcommons.usu.edu/etd/6494.
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Users of the Instream Flow Incremental Methodology CTFIM) commonly assume that there is a positive linear relationship between available habitat (WUA) and stream fish biomass. However, several studies have shown a lack cf correlation between WUA and biomass. Such poor relationships may occur if other factors limit fish abundance. Food availability is a potentially important factor limiting abundance of stream fishes and can affect blomass by influencing fish condition (individual weight). I collected rainbow trout (Oncorhynchus mykiss) exposed to different levels of invertebrate-drift density to determine if condition was greater where food was more abundant. I also examined whether size-selective predation and gut fullness varied with drift density.
Size-selective predation was not related to drift density. However, condition and gut fullness were both significantly correlated with drift density. Furthermore, changes in drift density appeared to have a stronger influence on small-trout condition than large-trout condition. The results of this study and others support the contention that the reliability of the IFIM might be improved if food availability were incorporated into models.