Knowledge of the relationships between environmental forcing and demographic parameters is important for predicting responses from climatic changes and to manage populations effectively. We explore the relationships between the proportion of sea cows (Dugong dugon) classified as calves and four climatic drivers (rainfall anomaly, Southern Oscillation El Niño Index [SOI], NINO 3.4 sea surface temperature index, and number of tropical cyclones) at a range of spatially distinct locations in Queensland, Australia, a region with relatively high dugong density. Dugong and calf data were obtained from standardized aerial surveys conducted along the study region. A range of lagged versions of each of the focal climatic drivers (1 to 4 years) were included in a global model containing the proportion of calves in each population crossed with each of the lagged versions of the climatic drivers to explore relationships. The relative influence of each predictor was estimated via Gibbs variable selection. The relationships between the proportion of dependent calves and the climatic drivers varied spatially and temporally, with climatic drivers influencing calf counts at sub-regional scales. Thus we recommend that the assessment of and management response to indirect climatic threats on dugongs should also occur at sub-regional scales.

People in 114 countries have consumed meat and other products from ~87 species of marine mammals since 1990. Nonetheless, assessment of the sustainability of most harvests is very difficult because information on the target populations and harvest numbers is inadequate. Dugongs have been harvested by the indigenous peoples of Torres Strait between Australia and Papua New Guinea, for at least 4000years; the harvest has been substantial for at least the last 400–500years. We use several lines of evidence to re-evaluate the sustainability of this harvest in the absence of robust data on the absolute size of this dugong population or the harvest. The evidence suggests that the harvest is sustainable. Dugong relative density was significantly higher in 2013 than in any other survey year and their Area of Occupancy has trended slightly upward since 1987. The proportion of calves in 2013 was the highest recorded. Genetic diversity is high. Dugongs are caught in only 5.0% of the 5268km2 of very high dugong density habitat as the result of the controls on the harvest and socio-economic factors. Nonetheless, many in the wider Australian community disapprove of this harvest and demand that hunting be banned. Enhancing culturally-appropriate spatial controls may be a more practical approach to managing this harvest than a more data-demanding Total Allowable Catch approach and may also be appropriate for some other indigenous harvests of marine mammals.

The management of dugongs (Dugong dugon) and green turtles (Chelonia mydas) is a complex social and ecological problem. Dugongs and green turtles are protected by Australian national and sub-national conservation legislation. Both species are important cultural, spiritual and economic (i.e., subsistence) resources for Indigenous Australians. In Australia, Aboriginal and Torres Strait Islander Traditional Owners may hunt these species to satisfy personal, domestic, or non-commercial communal needs. Torres Strait, not only has the largest population of dugongs in the world and one of the largest breeding populations of green turtles, but also has high rates of Indigenous hunting compared to other parts of Australia. Consequently, management of the traditional Torres Strait dugong and green turtle fisheries needs to include social–ecological considerations and involve Torres Strait Island communities. The ecological scales at which dugongs and green turtle operate are large. Dugongs undertake large-scale movements and green turtles undertake breeding migrations, which means the populations that are hunted by Torres Strait Islanders are also hunted or impacted by threats in other countries and in waters off mainland Australia. Thus, management of these populations needs to occur at local, state, national and international scales. To inform the development of management arrangements for the traditional dugong and green turtle fisheries in Torres Strait I aimed to provide an overall context for management at different spatial scales and investigate opportunities and challenges associated with co-management, particularly community-based monitoring. The development of a participatory research process, particularly the research agreement, cultural reference group and employment of Indigenous research counterparts was integral to the study being resilient to external perceptions of hunting reported in the media that threatened to cause hunters to withdraw their participation from the project. Without a process to establish trust, hunters were concerned that the information they provided would be used against them to stop them from hunting. Hence, the process I undertook confirms the importance of strong, resilient co-management partnerships. The risk to dugongs from hunting was evaluated based on spatial data about hunting patterns and dugong distribution and relative abundance. More than 60% (10,690 km²) of the areas supporting very high and high densities of dugongs are at low risk from hunting because hunting is largely restricted to areas close to inhabited islands (i.e., within 30 km). Nevertheless, the areas accessed by hunters also include a substantial amount (6,007 km²) of the very high and high dugong density areas, most of which are the 'sea country' of individual communities. A spatial decision framework based on knowledge of jurisdictional arrangements suggested that different types of management will be appropriate in different parts of the Torres Strait region and that the relative importance of different co-management partners changes with spatial scale. Hunters and elders from Hammond Island were interviewed regarding the need for local management, their perceptions of different management tools and multi-scale co-management from a community perspective. The Hammond Islanders considered some management tools, such as quotas and spatial management, appropriate to incorporate into co-management plans, but that other tools, such as seasonal closures and sex/size-based limits, were inappropriate because of social and cultural factors. Community-based management approaches were considered important especially the application of: (1) cultural norms to the development of tools to achieve compliance and enforcement within the community; and (2) consensus-based decision-making, with regard to the use of more formal rules. The need for cooperation with other communities and stakeholders across spatial scales was also recognised, particularly with regard to enforcement. Overall, the results suggested that co-management is likely to be a more appropriate approach for managing dugongs and green turtles in Torres Strait than either community-based management or government-driven management. Re-analysis of data from two catch-monitoring projects previously conducted in Torres Strait to collect catch statistics and/or life-history parameters on dugongs: (1) occasional sampling and (2) census by an outsider showed that occasional sampling would not provide robust catch-estimates at the individual community level as required for community-based management. I investigated an alternative strategy that considered hunter as the sampling unit. Hunters in the Kaiwalagal communities of Hammond Island and Thursday Island recorded information on datasheets on the number of animals taken, demographic information about the animals taken and information on hunting patterns. Indigenous research counterparts recruited hunters to participate, distributed and collected datasheets, collected biological samples from harvested animals and helped provide feedback to hunters and their communities about the results and progress of the project. The results suggest that a community based approach, such as hunter self-monitoring, will be a more reliable and cost effective approach for determining catch-estimates for dugongs and green turtles to inform co-management at the community level than alternatives such as occasional sampling or census by scientists (e.g., professionally-based monitoring). Hunter self monitoring has fewer limitations and more benefits than the alternatives with respect to: accuracy and precision of the catch estimates, financial costs, trust by communities and capacity to feedback results to communities in a timely manner. Determining the sustainability of the catch requires demographic information about the animals taken as well as the number of animals taken. Hunters recorded information that was more straightforward (e.g., sex) more often than information that was more complex (e.g., reproductive status) and specimens were rarely collected. In addition, hunters did not record unsuccessful trips and therefore an understanding of catch-per-unit-effort could not be obtained. The amount and complexity of information to be collected should ideally be increased in stages as hunters become more proficient, with training in the provision of information at each stage. Collection of information about hunting patterns, including social and cultural considerations, can provide important insight about hunting pressure, which can be useful for guiding decisions regarding the choice and application of management tools. Some of the management options included in the Community Dugong and Turtle Management Plans of other Torres Strait communities, such as stopping spotlighting of green turtles at night, could be effective in reducing catch, but could be difficult to implement. Dugongs and green turtles were caught mostly for general consumption. Therefore, management strategies that limit hunting to ceremonies may be difficult to implement due to the social pressure on hunters, particularly the few prolific hunters who are regularly asked by others to hunt for them. Thus, efforts to change beliefs and behaviours regarding hunting management needs to go beyond hunters to the broader community. Although community-based catch-monitoring will be more appropriate than occasional sampling by professionals to inform co-management of the Torres Strait dugong and green turtle fisheries, there are significant challenges to its implementation. Obtaining insights into the population status and sustainability of the catch will require monitoring temporal trends in a series of indicators using a framework, such as developed in this thesis, to assist in accessing and coordinating the functions necessary to develop and implement a catch-monitoring project. Such a framework could be used by a coordinating organisation such as the Torres Strait Regional Authority to access the necessary technical skills and plan a monitoring project, including highlighting where capacity-building is needed.

One of the largest populations of green turtles (Chelonia mydas) in the world spends at least part of its life cycle in the remote Torres Strait between Australia and Papua New Guinea. This population is subjected to traditional harvests from geographically dispersed communities including along the northern and eastern coasts of Australia, Indonesia and south-western Pacific nations. In Torres Strait, green turtle hunting is classed as a traditional fishery and is guaranteed by Australian legislation (Native Title Act 1993) and the Torres Strait Treaty between Australia and Papua New Guinea that aims to protect the traditional lifestyle of the region′s indigenous peoples. To investigate the Islanders′ thoughts and aspirations regarding marine turtle management, we interviewed hunters and Islander Elders from the Hammond Island community in the Kaurareg nation of Kaiwalagal. Although not the Traditional Owners of the Kaiwalagal sea country in which they live and hunt, Hammond Islanders wish to be involved in the management of resources on which they depend, including marine turtles. They considered community-based processes to be important, especially the application of (1) cultural norms to the development of tools to achieve compliance and enforcement within the community, and (2) consensus-based decision-making amongst hunters and elders within the community, with regard to the use of more formal rules. However, the need for co-operation with other communities and stakeholders across scales was also recognised, particularly with regard to enforcement. Our results suggest that co-management is likely to be a more appropriate approach for managing green turtles in Torres Strait than either community-based management or government-driven management.

Chitons of the genus Ischnochiton are found predominantly on the undersurfaces of boulders, compared with other intertidal or subtidal habitats. They therefore appear to be habitat-specialists at this scale. This, combined with the fact that boulder fields are relatively sparse compared with other intertidal habitats, makes these animals vulnerable to natural and anthropogenic disturbances. In addition, many species of Ischnochiton are relatively rare and appear to have very patchy abundances, making them likely to have very specific requirements for habitat. We need to understand the habitat requirements in order to manage, conserve and restore disturbed habitats. The present study was carried out at three intertidal boulder fields separated along approximately 200 km of the coast of New South Wales, Australia, centred around Sydney. The boulder fields were representative of those found in this region. The boulders were made of different materials: shale in the north, sandstone in Sydney and quartzitic sandstone in the south. Some boulders in each boulder field were covered by up to 0.4 m of water during low tide. The study showed that the seven species examined were overdispersed among boulders in each of these three intertidal boulder fields. Most boulders did not have associated chitons, but there were very large abundances on a very small number of boulders. Chitons were also overdispersed among boulders that they occupied. These patterns were consistent among shores and among species, even though patterns of abundance were extremely different among different species. These species appear therefore to show specific requirements for habitat at a small spatial scale, using only a small proportion of potential patches of habitat (i.e. boulders) in any place. Extremely patchy patterns of dispersion can be caused by variation in patterns of recruitment, mortality or behavioural responses to habitat or other species. Before performing experiments to investigate such processes, it is useful to test hypotheses of association with habitat using mensurative experiments to identify environmental correlates that might explain the observed patterns. In the present study, sizes of boulders and the associated sessile and mobile assemblages were proposed as mechanisms that could affect dispersion of chitons among boulders. None of these factors, however, showed strong associations with abundances of chitons. The lack of support of these models rules out some features of habitat to which species of Ischnochiton might respond, thereby precluding manipulative experiments involving these features, which are unlikely to be involved in the very patchy patterns of dispersion of species of Ischnochiton.

Wetlands in urban areas are often restored in an attempt to reduce the loss of such habitats. Unfortunately, the success, or otherwise, of programmes of restoration has rarely been systematically gauged. Through not knowing whether programmes of restoration are successful or not, valuable resources potentially continue to be wasted, wetland habitats remain degraded and the methods of restoration are not assessed for future programmes of restoration.Several factors have contributed to poor assessment of restoration of urban wetlands. First, often the goals of restoration have been unrealistic because they failed to consider that wetlands in urban areas are subjected to ongoing and often largescale anthropogenic disturbances. Second, goals of restoration often have nor been clearly defined and, consequently, predictive hypotheses were not formulated to test for the success of restoration. Third, even when success of restoration has been assessed, this has not always been adequate because of inappropriate sampling design.Such problems can be overcome by treating restoration of habitat as experiments and using the knowledge gained from each project to improve future programmes of restoration. This will ensure that the remaining semi-natural habitats along coasts in urban areas can be more effectively managed. (C) 1999 Elsevier Science B.V. All rights reserved.