Thesis (Ph. D.)--University of Hawaii at Manoa, 1994. / Includes bibliographical references (leaves 166-191). / Microfiche. / xiii, 191 leaves, bound ill. 29 cm

Due to the critical status of Psammobates geometricus and the vulnerability of their habitat, there is a need to allocate areas for their protection. The aim of this study was to provide information on the space requirements and activity level of geometric tortoises to facilitate future conservation efforts.

Glutathione transferases (GSTs) are good candidates for investigations of enzyme evolution, due to their broad substrate specificities and structural homology. The primary role of GSTs is to act as phase II detoxifying enzymes protecting the cell from toxic compounds of both endo- and exogenous origins. The detoxification is conducted via conjugation with glutathione (GSH), which facilitates their removal from the body. The work presented in this thesis has supported a theory for enzyme evolution when the multiple pathway to novel functions can been seen to involve a “generalist” state from which “specialist” states with a new activities can evolve. The generalist has broader specificity and lower activity than the specialist. The term quasi-species is used for a group or cluster of enzyme variants with similar functional properties, and this entity has been suggested as the fittest group for further evolution. This is based on studies of the evolution of new GST variants in two generation. Three diverging clusters or quasi-species, with diverging substrate selectivity, were identified from a GST M1/M2 library, by using directed evolution (family DNA shuffling), multiple substrate screening and multivariate statistics as tools. One of the clusters was M1-like and the other was M2-like, both functionally and structurally. The third quasi-species diverged orthogonally from the parent-like distributions. Its functional character can be referred to as a “generalist” as it had lower activities with most of the substrates assayed except for epoxy-3-(4-nitrophenoxy)-propane (EPNP) and p-nitrophenyl acetate (pNPA). Another round of family DNA shuffling was made with selected variants from the “generalist” quasi-species. From the second generation three quasi-species emerged with diverging functions and sequences. The major cluster contained enzyme variants that represented a direct propagation of the generalists. Diverging from the generalists was a cluster with high specificity with isothiocyanates (ITCs). Increased ITC specificity and decreased epoxide specificity was observed among the novel variants (specialists). The change in functional properties was attributed to a Tyr116His substitution in the active site. These results demonstrate the usefulness of multivariate analysis in the quest for novel enzyme quasi-species in a multi-substrate space, and how minimal changes in the active site can generate distinctive functional properties. An application of our method could be identification of enzyme quasi-species that have lost their sensitivity with alternative inhibitors.

The secondary productivity of communities is inherently influenced by the availability and quality of food resources. Movement of organic matter (OM) across landscapes can connect adjacent systems by providing subsidies of carbon and nutrients, implying that alterations of environments from their natural state may affect the productivity of neighboring food webs. The intact terrestrial and marine environments of Fiordland provide a setting to study linkages between the land and the sea. The first general objective of this study was to determine if large but nutritionally poor (nitrogen-poor, carbon-rich) inputs of forest litter support marine secondary production, and to identify pathways for incorporation of this material into upper trophic levels. Pools of marine and terrestrial OM had distinct values of [delta]�⁵N, [delta]��C and [delta]�⁴S, providing high power to estimate the relative use of these sources by the food webs of the fjord-head deltas. Deposit feeding invertebrates (e.g. Echinocardium cordatum, Pectinaria australis) directly assimilated plant detritus. Heterotrophic bacteria on the surface of the sediment assimilated forest litter and provided a potential food source for invertebrates. Chemoautotrophic bacteria fix CO₂ that originates from decomposing forest litter, thus providing an indirect pathway for incorporation of forest litter into the food webs. In the deep basins the strength of the flux of uptake by chemoautotrophic bacteria through the benthic food web into the upper trophic levels was demonstrated by hagfish (Eptatretus cirrhatus) obtaining 38-51% of their nutrition from these bacteria. The ability of a community to utilize discrete sources of OM relies on the presence of specific functional feeding guilds. Marine algae provide a highly nutritive (nitrogen-rich) food source for the fjord communities and fluxes of algae into food webs are facilitated by grazing invertebrates and filter feeders. The second general objective of this study was to determine how the effective loss of filter feeders from inner Doubtful Sound would alter the flux of marine-derived OM to the food webs of the delta communities. The low salinity environment imposed by the hydroelectric power station in Doubtful Sound caused a large reduction in the abundance of the infaunal bivalves Austrovenus stutchburyi and Paphies australis from delta habitats. Clams could tolerate periods of freshwater exposure of [less than or equal to]20 days duration, but the constant freshwater conditions in Doubtful Sound decreased survivorship. In 2004/05 the biomass of these species in inner Doubtful Sound (7.28 tonnes) was 29 times smaller than in Bradshaw Sound (214.12 tonnes). The associated loss of biodeposits (~91 tonnes(DW) yr⁻� in Bradshaw Sound vs. 1 tonne(DW) yr⁻� in inner Doubtful Sound) may have also altered the flux of nutritive OM to the infaunal community. The river delta communities in inner Doubtful Sound appear to have a higher reliance on forest litter than those in Bradshaw Sound, which is apparent as low values of [delta]�⁵N and [delta]��C for estuarine fish (Notolabrus celidotus, Hemerocoetes monopterygius), which act as integrators of the benthic community. This study demonstrates important linkages between terrestrial and coastal marine ecosystems and highlights the role of functional diversity in facilitating fluxes of organic material through food webs.

The objectives of studies undertaken here were to identify the species of Colletotrichum associated with coffee berry anthracnose in PNG, gain an understanding of the infection process and factors affecting it, assess the impact, if any, of anthracnose on coffee quality and identify suitable chemicals for anthracnose control. A total of 40 isolates were collected from PNG and their cultural and morphological characteristics on PDA were studied and used to identify the species. Species identification was further confirmed by molecular characterisation using RFLP and DNA sequencing of the ITS region of the rDNA. After species identification only two isolates were selected to represent C. gloeosporioides and C. acutatum for further studies. Studies on conidia germination and the effects of conidia concentration, temperature, relative humidity and pH affecting germination were done on TWA, followed by studies on the infection process on coffee berries and the influence of temperature on germination and appressoria formation in vivo. For assessment of effect of anthracnose on coffee quality, 100 samples of ripe berries were assessed for disease incidence, followed by processing of the berries to green bean and data on bean defects (black bean) together with anthracnose incidence subjected to appropriate statistical analysis. A similar procedure was followed using disease severity but the samples were from one farm only. The closing work on chemical control was done by screening 16 different fungicides for the control of C. gloeosporioides and C. acutatum. With the 40 isolates, 29 were identified as C. gloeosporioides and 11 as C. acutatum. This is the first report of C. acutatum on coffee in PNG. Identification of the species was further confirmed by RFLP groupings where C. gloeosporioides and C. acutatum were separated at 574bp and 584bp respectively and DNA sequence homology identified the PNG isolates with C. gloeosporioides and C. acutatum accessions. Optimum conditions for conidia germination in relation to spore concentration, temperature, and pH are 1 x 106 spores/ml, 21 - 29°C and pH 5 - 7 respectively for C. acutatum and for C. gloeosporioides 1 x 106 spores/ml, 25 - 31°C and pH 5 - 7 respectively. Humidity is not a limiting factor for activity of both species. Infection process for both species is similar where conidia germinate to produce the germ tube which swells at the tip to form the appressoria. The appressoria produce an infection peg which is responsible for berry cuticle penetration and cell colonisation (resulting in typical anthracnose symptom expression) and eventual sporulation. C. acutatum has not been reported elsewhere as a pathogen of coffee and this is the first report of C. acutatum causing infections on both ripe and mature green berries. Anthracnose incidence did not correlate well with coffee bean defects, but anthracnose severity v suggested that coffee quality could be affected by anthracnose. The most effective fungicide for anthracnose control is thiram alone or thiram alternating with propiconazole.

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Loss of biodiversity is a major environmental issue in Australia. In response the Commonwealth Government has developed a national list of threatened species and prepared recovery plans under the provisions of the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999 (EPBCA). However, knowledge on the appropriateness and effectiveness of those conservation and management schemes is limited. The aim of the thesis was to conduct an evaluation of recovery planning to assess its appropriateness as a conservation and management instrument, and investigate how legislative, institutional and organisational factors influence its implementation. Four research questions were addressed: 1) How does recovery planning operate in regard to legislative, jurisdictional and institutional aspects? 2) Do recovery plans comply with legislative requirements and coherent conservation planning? 3) What management factors have most influence on implementation of recovery plans at state level? and 4) What modifications could be made to the management system to improve implementation of recovery plans? The major approaches considered in this study were policy evaluation and systems analysis. Both approaches were incorporated in a framework of the thesis to construct a conceptualisation of the threatened species management system as a model. This allowed examining its structure, key elements and dynamics, and evaluation of its performance and effectiveness. Methods comprised interviews, content analysis of program documentation, qualitative and quantitative analysis of recovery plans, experts’ workshops, and systems analysis and modelling. The major set of quantitative data came from a database which incorporated content attributes of 236 recovery plans. Taking into account the Australian legislative requirements for preparing recovery plans, key content attributes were selected for assessing the degree of compliance. Internal consistency of plans was also assessed as a complementary measure of coherent management planning. Measures of internal consistency were: consistency between gaps of scientific information versus prescribed actions calling for research; consistency between major threatening processes versus prescription of threat abatement actions; and consistency between recovery objectives versus performance criteria for measuring achievement of objectives. Another component of the thesis was the construction of a model of the management system of threatened species. This theoretical model was conceptualised from opinions of experts and stakeholders occupying key roles in threatened species management. The model incorporated social aspects of management such as institutional and organisational factors influencing planning and the implementation of recovery plans. The model was built using a Bayesian belief network to assess the most influential components (issues, recovery strategies, and management requirements) on the likely outcomes. Expert opinions also assisted to identify gaps in the management system and formulate new management strategies. Finally, modelling allowed assessing different management scenarios and identified the key components that would improve recovery planning. Major findings of the investigation revealed that: 1) Although the three levels of government in Australia (Commonwealth, state/territory and local) are involved in recovery planning, it is the states/territories that have the most active role in preparing and operating recovery plans. State and territory-based legislation, policy and conservation strategies shape the form in which recovery planning is performed nationwide, as they are responsible for implementing 89% of national plans; 2) Overall compliance of plans with legislative requirements was adequate; although improvement is required in establishing a monitoring and evaluation framework. Overall, internal consistency of plans was also adequate in addressing threats and formulating research for knowledge gaps; but consistency was poor regarding the response to some threatening processes and the establishment of recovery criteria; 3) According to experts/stakeholders, the most influential issues relevant to the implementation of recovery plans are: coordination across Commonwealth, state and territory agencies, inconsistency of strategies and programs across jurisdictions, addressing management of threatened species on private land, incorporation of science into recovery planning, prioritising schemes for conservation action, and funding for the implementation of plans; 4) The recovery planning strategy may be improved by establishing mandatory monitoring and review reports; creating a national forum on threatened species; designing an appropriate insurance regime for volunteers; and establishing a national management information system.