288 resultados para Estuaries -- Victoria, Western -- Management


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Government environment protection policies for waterways have traditionally relied on water quality indicators and their objectives. In this paper we describe the development of biological objectives based on invertebrate indicators for inclusion in a government policy for the catchment of Western Port Bay, Victoria. The first step of defining segments (areas with streams in which the same objectives are applied) was problematic, requiring two different approaches, as follows. Site groups initially based on invertebrate community composition derived using multivariate techniques (ordination and classification) proved to be unsuitable for policy segments. Segment boundaries were subsequently defined using topographical (e.g. boundary of foothills and lowland plains), climate (e.g. rainfall) and land-use (e.g. urban) features. We used information and data from reference sites inside as well outside the catchment to derive specific biological objectives based on aquatic invertebrates for these segments. Objectives were specified for the following four indicators – number of invertebrate families, the SIGNAL index, the AUSRIVAS predictive model and the number of key families.

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This article aims to investigate the need for effective exchanges between knowledge generators and knowledge users in water management. Firstly, we explore the use of adaptive management for water governance and then outline the communication issues of water-management knowledge at a regional scale. Central to this approach is the need to harness 'local' knowledge that can be used to develop community participation in local water governance. Accordingly, we propose a three-network communication model to illustrate the process and identify the issues of concern for developing place-based strategies. Since research plays a central role in knowledge generation, one of the first ways to proceed is to recognise local research and incorporate it into an inclusive decision-making process. One way to achieve this is through the development of regional networks that are openly available to all, and we explore this by focusing on the place of 'network thinking' at local scale using a newly developed regional network for local knowledge dissemination in south-west Victoria, Australia. We conclude that so far this new network is too heavily reliant upon one web-based tool and outline a broader range of strategies that can be used to achieve its aims.

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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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This thesis explores the issue of men's access to chronic illness self management programs from a social constructionist perspective. A combination of research methodologies was used; a quantitative analysis to confirm gender differences in levels and patterns of service use; a qualitative analysis to gain an increased understanding of the factors affecting men's access; and a trial to test the application of the research findings. The clients and services of Arthritis Victoria were chosen as the setting for this research. The quantitative analyses were conducted on contingency tables and odds ratios and confirmed that men were under-represented as service users. The analyses also identified gender differences in patterns of service use. The qualitative analysis was based on a series of in-depth, semi-structured interviews. It was undertaken from a grounded theory approach to allow for the development of theoretical explanations grounded in the data. It was found that men's decisions to access chronic illness self management programs were strongly influenced by dominant social constructions of masculinity which constrained help-seeking and health management behaviour. However, the restrictive influence of hegemonic masculinity was progressively undermined by the increasing severity of the chronic condition until a crisis point was reached in terms of the severity of the condition or its impact on lifestyle. This resulted in a reformulation or rejection of hegemonic masculinity. The described conceptual framework was consistent for men from diverse social groupings, although it appeared less prominent in both younger and older men, suggesting that dominant social constructions of masculinity have the greatest influence on health decisions during the middle stage of adulthood when work and family obligations are greatest. The thesis findings informed the development of some guiding principles for reviewing the structure and delivery of chronic illness self management services for men. The guiding principles will have direct application in the planning of Arthritis Victoria programs, and implications for other chronic illness self management programs in Australia, and also in Western countries with a similar health and sociocultural setting to Australia.

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This study examined the factors affecting the distribution and abundance of epifaunal caridean shrimps in seagrass meadows of the Hopkins River estuary in south-western Victoria, Australia, and investigated the life history patterns of the freshwater Parana australiensis, found for the first time in estuaries. Adult and sub-adult shrimps were surveyed in seagrass meadows along the estuary over two years, and their planktonic larvae were surveyed in adjacent waters. Three species were collected. The marine Palaemon serenus occurred only near the mouth, summer to autumn, in high salinities. The marine/estuarine Macrobrachium intermedium occurred throughout the estuary. Adults were most abundant in late autumn, and least abundant in summer (unlike trends reported in marine meadows). Densities were higher and less variable in downstream meadows. P. australiensis occurred in the upper estuary all year, most abundantly in spring, due to migration from the river after peak discharge. Ovigerous females dominated, while males, showing less migration into the estuary, dominated above estuarine influence. Adults disappeared from the estuary in summer as salinity rose. Breeding period for P. australiensis was briefer in the estuary (September-December) than upstream (July-April). M. intermedium began breeding later in the upper estuary (November/December-March) than in the lower estuary (October-March), probably reflecting a physiological response to lower salinity, rather than an interaction with P. australiensis. No ovigerous P. serenus were found in the estuary. Larvae of P. australiensis and M intermedium occurred abundantly throughout the estuary, but P. serenus larvae did not. P. australiensis was an early coloniser to the plankton after peak discharge (November-December). Larvae concentrated in the deep saline layer at the head of the intruding salt wedge, thus probably maintaining longitudinal position. Diurnal vertical migrations were evident within the salt wedge, and in a deep pool above tidal influence. M. intermedium larvae occurred October-May in the lower estuary and November-April in the upper estuary, peaking in abundance one to two months after P. australiensis. They were associated with low surface flows and surface salinities greater than 10, over an anoxic deeper layer. All three species exhibited extended development of euryhaline larvae in the laboratory. Tolerances and optimal salinities of larvae of the three species reflected their distributions. M. intermedium was the most euryhaline species. P. australiensis larvae were tolerant of higher salinities than juveniles of adults: capable of developing in salinity of at least 15. Most P. australiensis juveniles recruited to the estuary November-December, after which numbers declined dramatically. After settlement, most recruits probably migrated upstream out of the estuary. Two cohorts of M. intermedium recruited to the estuary from larvae in summer (December and February), but some juveniles also migrated from adjacent coastal waters. Post-larval migration was at least as important a determinant of abundance as direct recruitment from estuarine, planktonic larvae in all three species. Distributions among seagrass meadows along the estuary were determined primarily by physico-chemical patterns driven by hydrological changes. Seasonal variations in salinity and temperature were strongly associated with seasonal variations in shrimp abundance. Salinity tolerances of adults of the three species reflected their distribution patterns. Biotic interactions were more important in determining distributions within meadows. P. australiensis, when abundant, were associated with seagrass biomass. M. intermedium were also, but when seagrass was sparsest and least extensive. The two species apparently partitioned the seagrass meadow according to depth in early summer. Laboratory experiments suggested P. australiensis was displaced from deeper water by M. intermedium. Preference for vegetative complexity and competition for position within meadows suggest the underlying importance of predation in regulating shrimp populations. A survey of south-eastern Australian estuaries found P. australiensis larvae abundant in all stable, open, well-developed, salt-wedge estuaries where adults were abundant. Adults were most abundant in low salinities among submerged leafy macrophytes. Reproductive traits of P. australiensis were compared in estuarine and fresh reaches of three rivers. Early in the breeding season, egg size was smaller, and (size-specific) egg number larger in estuaries than upstream. A trade-off between egg size and egg number resulted in no difference in total (size-specific) reproductive investment between locations. Reproductive investment tended to decrease at some locations over the breeding season, and this decrease was a result of decreased egg size in most cases. The decrease in reproductive investment probably reflected reduced food availability for the adult, while the reduced egg size was probably a response to improved conditions for larval development. In the Hopkins River, larger egg size at upstream sites was reflected in larger early stage larvae. Later stage larvae were larger in the estuary, suggesting more favourable conditions for larval development. Allozyme electrophoresis showed the P. australiensis populations in each of the three rivers to be distinct. Allozyme frequencies were not different within the Hopkins River, but upstream and estuarine locations in the Curdies and Gellibrand were different. Although some variation in reproductive traits within catchments may have been due to genotypic differences, trade-offs between egg size and number, and decreases in egg size over summer were probably due to plastic responses to environmental cues. It is proposed P. australiensis inhabits and reproduces in both estuarine and freshwater environments by plastic response to environmental conditions. Recruitment to estuaries is dependent on the presence of suitable adult, littoral habitat, and a stable salt wedge for larval retention. Estuaries are important recruitment sites for P. australiensis, potentially allowing an extra brood each year before riverine recruitment. Estuarine broods could constitute a large part of the total fecundity of P. australiensis females. Euryhaline larvae and estuarine recruitment of P. australiensis suggest marine transport of larvae between estuaries as a possible dispersal mechanism for Paratya species.

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The concentrations of various forms of nitrogen and phosphorus in the main stream and selected tributaries of Pirron Yallock Creek, southwestern Victoria were examined over a two-year period. Exceedingly high levels of both nutrients were found within a particular tributary, while generally high nutrient levels were observed throughout the catchment. The speciation results indicated that dairy effluent was the primary source of nutrients to Pirron Yallock Creek. A palaeolimnological study was undertaken to determine the impact of European settlement upon waterway nutrient concentrations within the region. The palaeolimnological study focused primarily on the diatom flora preserved within the sediments of nearby Lakes Corangamite and Bullen Merri. Lack of preservation of diatoms within the sediments of Lake Corangamite resulted in no water quality inferences for this lake. The preserved diatoms within Lake Bullen Merri suggested an increase in trophic status of this lake during the last 500 years. While a change in the diatom flora of Lake Bullen Merri was evident, it was not possible to differentiate the impact of European settlement upon nutrient status of this waterway from long-term trophic status change. In light of the particularly high nutrient concentrations observed in Pirron Yallock Creek, improved nutrient management strategies are proposed for the catchment. These strategies, which consider current nutrient management activities, are predominantly focussed on the dairy industry, which occupies the majority of the catchment.

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The Gippsland Lakes region in eastern Victoria is a partially flushed coastal lake system within a diverse catchment of rural and urban communities. Pressure from lakeside developments, re-occurring blue-green algal blooms, declining fisheries, sedimentation and infilling of the ocean entrance, has borne several decades of focussed studies and routine monitoring programs, along with a variety of engineering and management solutions. A recent review recommended that these disparate studies should be enhanced to formulate a coordinated monitoring network that could improve both spatial and temporal coverage, develop a capacity to trigger responsive investigations and was able to serve the needs of system management. Through a series of partnerships an integrated network was developed that comprises event and baseline monitoring of catchment loads, local meteorological forcing and an array of water quality sampling sites within the lakes system. A majority of these sites are incorporated with real-time telemetry that provides up to the minute information to stakeholders via a web-based information management system and vital operational status to technical system management.

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The thesis investigates two adjacent volcanic maar lakes, with differences in chemical and biological properties. Lake Bullen Merri a brackish, phosphorous-limited lake that suffers from nuisance algal blooms and Lake Purrumbete a fresh, nitrogen-limited lake with diverse phytoplankton assemblage. Nutrient fluxes for both lakes are dominated by internal cycling.

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Sustainable forest management has emerged as a major international forestry issue. This research assessed the potential contribution of certification and labelling to sustainable forest management in Victoria. The results indicate a potential demand for certified forest products and a consumer willingness to pay to ensure forests are managed sustainably.

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The basic limnology, nutrient and hydraulic budgets and recent history (using fossil remains in the sediments) of Lake Wallace have been studies to determine factors that predispose the lake to the development of potentially toxic algal blooms.

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There is a growing recognition of the complexity of environmental issues and acceptance of the value of more integrated approaches to address them. Evidence of progress with the development of more integrated approaches is however less clear cut. Within this context, this paper explores how a more integrated approach 10 natural resource management at a state government level could be progressed. Using recent experience in Victoria as a focus, this paper provides an overview of environment and natural resources issues confronting the State. highlights why integration is an important element of any response. and outlines the current policy and organisational context. Possible elements of a state-wide policy framework for more integrated natural resource management across a state government organisation are also outlined and discussed.