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You searched for +publisher:"University of Otago" +contributor:("Wilson, John Bastow"). Showing records 1 – 2 of 2 total matches.

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University of Otago

1. Camara, Amadou. The role of shrubs and rabbit herbivory in the ecological restoration of the drylands of south-central New Zealand .

Degree: 2011, University of Otago

The net outcome of the interaction between woody and herbaceous plant species can be positive or negative depending on plant species and environmental conditions. Positive interactions (facilitation) are postulated to be more prevalent and negative interactions (competition) less prevalent, under high environmental severity. Positive interactions have been attributed to the so-called ‘fertile islands’ and ‘nurse plant’ effects. The ‘fertile islands’ and the ‘nurse plant’ effects are suggested mechanisms for plant interactions in arid and semi-arid environments worldwide. Some indigenous plants in dryland New Zealand are postulated to have grown under a woody canopy and may benefit from the restoration of the woody habitat. However, restoration of indigenous plants may be impeded by mammalian herbivory. In this study, the ‘fertile islands’ and the ‘nurse plant’ effects and their possible role in the ecological restoration of a predominantly indigenous dryland mixed woody and herbaceous vegetation, were investigated, in the presence and absence of rabbit herbivory, in the dry sub-humid Central Otago by field experiments and by glasshouse ecophysiological experiments. The fertile islands effect was investigated by comparing soil properties under four shrub species to those of the adjacent grassland. Soils under Kunzea ericoides and Coprosma propinqua were more fertile compared to those of the grassland. Soils under two other species Discaria toumatou and Rosa rubiginosa were not significantly different in fertility from soils in the grassland. The nurse plant effect was tested in the field by comparing the height growth and survival of five planted herbaceous plant species as well as the natural recruitment of herbaceous species under a shrub canopy to those of the adjacent grassland, with or without grazing. In general there was no significant difference in height growth or survival between plants under a shrub canopy and those in the grassland. Grazing had a negative effect on the height growth and survival of herbaceous plant species. Herbaceous plant species richness under a canopy differed with shrub species and season of measurement. Effects of a shrub canopy on herbaceous plant species richness ranged from mainly positive (Rosa rubiginosa) to mainly positive but inconsistent (Coprosma propinqua and Discaria toumatou) and mainly negative but scale-dependent (Kunzea ericoides). However, herbaceous plant species composition was not significantly different between areas under a shrub canopy and the adjacent grassland. The nurse plant effect was also examined experimentally in the glasshouse by comparing the response of the same five herbaceous plant species to light and defoliation. All five herbaceous plant species showed some degree of shade tolerance with higher concentrations of leaf total chlorophyll under shade than in full light. Acaena buchananii, Luzula ulophylla and Carex breviculmis showed lower range of shade tolerance than Anthoxanthum odoratum and Acaena agnipila. Acaena buchananii and Carex… Advisors/Committee Members: Wilson, John Bastow (advisor).

Subjects/Keywords: Herbivory; drylands; ecological restoration; fertile islands; nurse plant

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Camara, A. (2011). The role of shrubs and rabbit herbivory in the ecological restoration of the drylands of south-central New Zealand . (Doctoral Dissertation). University of Otago. Retrieved from http://hdl.handle.net/10523/605

Chicago Manual of Style (16th Edition):

Camara, Amadou. “The role of shrubs and rabbit herbivory in the ecological restoration of the drylands of south-central New Zealand .” 2011. Doctoral Dissertation, University of Otago. Accessed July 07, 2020. http://hdl.handle.net/10523/605.

MLA Handbook (7th Edition):

Camara, Amadou. “The role of shrubs and rabbit herbivory in the ecological restoration of the drylands of south-central New Zealand .” 2011. Web. 07 Jul 2020.

Vancouver:

Camara A. The role of shrubs and rabbit herbivory in the ecological restoration of the drylands of south-central New Zealand . [Internet] [Doctoral dissertation]. University of Otago; 2011. [cited 2020 Jul 07]. Available from: http://hdl.handle.net/10523/605.

Council of Science Editors:

Camara A. The role of shrubs and rabbit herbivory in the ecological restoration of the drylands of south-central New Zealand . [Doctoral Dissertation]. University of Otago; 2011. Available from: http://hdl.handle.net/10523/605


University of Otago

2. Lawrence Lodge, Rachael Helen Elizabeth. Aspects of Alpha-niche differentiation in an herbaceous community .

Degree: University of Otago

Alpha-niche differentiation arises when plant species use resources differently enough to co-exist and persist within a community (Wilson 2011). If alpha-niche differentiation is occurring at a fine scale, a community including non-random groupings of species with divergent functional traits is expected (de Bello et al. 2009). The Botany Lawn community offers a unique opportunity to investigate alpha-niche differentiation as non-random groupings of the most abundant species; the “intrinsic guilds” have already been identified by Wilson and Roxburgh (1994). In this thesis, investigations focussed on functional traits which potentially allow alpha-niche differentiation at a fine scale with regard to the light and nutrient (resource) niches. Functional traits of fourteen of the intrinsic guild species were examined and agreement sought between species’ traits and their intrinsic guild membership, i.e. divergent traits between non-random groupings of species indicating the occurrence of alpha-niche differentiation. This thesis compliments and extends previous research seeking to identify mechanisms of alpha-niche differentiation within the Botany Lawn community. Mason and Wilson (2006) suggested differences in nutrient strategy were the basis for a mechanism driving community structure while Brownstein (2011) found agreement between intrinsic guild membership and growth responses under altered light conditions. The potential partitioning of the light niche was explored in two separate experiments. In the first, species were characterised by their relative growth rates and biomass allocation under ambient (high-) versus shaded (low-) light conditions. In the second experiment, antioxidant metabolism responses to light-mediated stress were assessed using reciprocal transfers between high and low light conditions. Aspects of the nutrient niche as a means for alpha-niche differentiation were addressed in three further experiments. The first of these compared nutrient contents, relative growth rates and biomass allocation when nitrate and phosphate were omitted or supplied. Uptake of various forms of nitrogen or phosphorus, differing in their biological availabilities, were the focus of the remaining experiments. Evidence for alpha-niche differentiation was mixed. Species differed in their functional traits throughout the experiments which, in theory at least, reflect differences in resource use. Agreement between species’ functional traits and their intrinsic guild membership was limited and appeared to be driven more by inherent differences than in response to the conditions. The clear exception was the greater antioxidant metabolism responses of intrinsic guild A compared to intrinsic guild B. The relationship between the measured species’ traits and intrinsic guilds and the benefits of employing such an approach are examined. Based on these results, it was unclear whether alpha-niche differentiation of the light or nutrient niches is driving the observed intrinsic guild structure of the Botany Lawn. While this… Advisors/Committee Members: Wilson, John Bastow (advisor).

Subjects/Keywords: alpha-niche; alpha-niche differentiation; assembly rules; relative growth rate; antioxidant metabolism; nitrogen; phosphorus; plant community ecology; functional trait; biomass allocation; intrinsic guilds

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Lawrence Lodge, R. H. E. (n.d.). Aspects of Alpha-niche differentiation in an herbaceous community . (Doctoral Dissertation). University of Otago. Retrieved from http://hdl.handle.net/10523/6617

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Chicago Manual of Style (16th Edition):

Lawrence Lodge, Rachael Helen Elizabeth. “Aspects of Alpha-niche differentiation in an herbaceous community .” Doctoral Dissertation, University of Otago. Accessed July 07, 2020. http://hdl.handle.net/10523/6617.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

MLA Handbook (7th Edition):

Lawrence Lodge, Rachael Helen Elizabeth. “Aspects of Alpha-niche differentiation in an herbaceous community .” Web. 07 Jul 2020.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Vancouver:

Lawrence Lodge RHE. Aspects of Alpha-niche differentiation in an herbaceous community . [Internet] [Doctoral dissertation]. University of Otago; [cited 2020 Jul 07]. Available from: http://hdl.handle.net/10523/6617.

Note: this citation may be lacking information needed for this citation format:
No year of publication.

Council of Science Editors:

Lawrence Lodge RHE. Aspects of Alpha-niche differentiation in an herbaceous community . [Doctoral Dissertation]. University of Otago; Available from: http://hdl.handle.net/10523/6617

Note: this citation may be lacking information needed for this citation format:
No year of publication.

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