Environment, resource sustainability and sustainable behaviour: exploring perceptions of students in South West Victoria

The movement toward a sustainable future has begun in many parts of the world, as the seriousness of the environmental problems faced by the planet become more widely recognised. Waste reduction, improved efficiency of energy use, water saving devices and changes in modes of transport are the first steps in the transition to a sustainable future. The students of today will be the decision makers of tomorrow and, thus, can have a significant effect on future development and the environmentalimpacts of that development. If students today are to become active participants in the environmental decision-making process, education for sustainability becomes a key component in ensuring sustainable futures. There is a need to establish data describing students&rsquo; attitudes toward environmental and resource sustainability issues so that challenges to implementing sustainable development policy can be better recognised. The aims of this study were to identify the perceptions of students inthe south west region of Victoria regarding environment and resource sustainability, and to identify their level of participation in sustainable behaviours. A survey of students has found that global environmental issues perceived by students as being in urgent need of attention were access to freshwater, loss of tropical rainforest and exhaustion of natural resources. At the local level the most urgent issues identified were water pollution, salinization and soil degradation, and clearing of native vegetation. Students perceive that Australians are overusing natural resources. They indicated particular concern for the sustainability of fossil fuels, water, coastal environments and fisheries resources. The results of this study indicate that students are responding to concerns for the environment and resource sustainability by embracing some forms of sustainable behaviour. However, as educators we need to ensure thatthe link is made between environment and resource sustainability and the implementation of policies that will further encourage sustainable behaviour.<br /

Geographical Information Systems (GIS) and their role in sustainable planning : a case study from a Local Government Area (LGA) in Australia

A case study is used to demonstrate the application of Geographical Information Systems (GIS) to inform sustainable development. The suitability of the landscape to support tourism accommodation in a Local Government Area (LGA) is modelled by integrating existing datasets, including conservation areas, residential zones, major roads and known locations of tourism operators into a logistic regression framework. By using a data-driven approach an indication of the relative importance of each explanatory variable can be accounted for, therefore informing planners of the importance of different assets. In a region where tourism is reliant upon natural features, this use of information systems in conjunction with quantitative statistical modelling can value-add to existing datasets. The provision of this kind of knowledge is important as it would otherwise not factor into the decision-making process had the datasets been considered independently of each other &ndash; a concept that applies to both the public and private sectors.<br /

Changes in catch rates and length and age at maturity, but not growth, of an estuarine plotosid (Cnidoglanis macrocephalus) after heavy fishing

The hypothesis that heavy fishing pressure has led to changes in the biological characteristics of the estuary cobbler (Cnidoglanis macrocephalus) was tested in a large seasonally open estuary in southwestern Australia, where this species completes its life cycle and is the most valuable commercial fish species. Comparisons were made between seasonal data collected for this plotosid (eeltail catfish) in Wilson Inlet during 2005–08 and those recorded with the same fishery-independent sampling regime during 1987–89. These comparisons show that the proportions of larger and older individuals and the catch rates in the more recent period were far lower, i.e., they constituted reductions of 40% for fish ≥430 mm total length, 62% for fish ≥4 years of age, and 80% for catch rate. In addition, total mortality and fishing-induced mortality estimates increased by factors of ~2 and 2.5, respectively. The indications that the abundance and proportion of older C. macrocephalus declined between the two periods are consistent with the perception of long-term commercial fishermen and their shift toward using a smaller maximum gill net mesh to target this species. The sustained heavy fishing pressure on C. macrocephalus between 1987–89 and 2005–08 was accompanied by a marked reduction in length and age at maturity of this species. The shift in probabilistic maturation reaction norms toward smaller fish in 2005–08 and the lack of a conspicuous change in growth between the two periods indicate that the maturity changes were related to fishery-induced evolution rather than to compensatory responses to reduced fish densities

Benthic habitat mapping in coastal waters of south–east Australia

The Victorian Marine Mapping Project will improve knowledge on the location, spatial distribution, condition and extent of marine habitats and associated biodiversity in Victorian State waters. This information will guide informed decision making, enable priority setting, and assist in targeted natural resource management planning. This project entails benthic habitat mapping over 500 square kilometers of Victorian State waters using multibeam sonar, towed video and image classification techniques. Information collected includes seafloor topography, seafloor softness and hardness (reflectivity), and information on geology and benthic flora and fauna assemblages collectively comprising habitat. Computerized semi-automated classification techniques are also being developed to provide a cost effective approach to rapid mapping and assessment of coastal habitats.Habitat mapping is important for understanding and communicating the distribution of natural values within the marine environment. The coastal fringe of Victoria encompasses a rich and diverse ecosystem representative of coastal waters of South-east Australia. To date, extensive knowledge of these systems is limited due to the lack of available data. Knowledge of the distribution and extent of habitat is required to target management activities most effectively, and provide the basis to monitor and report on their status in the future.<br /

Integrating multibeam backscatter angular response, mosaic and bathymetry data for benthic habitat mapping

Multibeam echosounders (MBES) are increasingly becoming the tool of choice for marine habitat mapping applications. In turn, the rapid expansion of habitat mapping studies has resulted in a need for automated classification techniques to efficiently map benthic habitats, assess confidence in model outputs, and evaluate the importance of variables driving the patterns observed. The benthic habitat characterisation process often involves the analysis of MBES bathymetry, backscatter mosaic or angular response with observation data providing ground truth. However, studies that make use of the full range of MBES outputs within a single classification process are limited. We present an approach that integrates backscatter angular response with MBES bathymetry, backscatter mosaic and their derivatives in a classification process using a Random Forests (RF) machine-learning algorithm to predict the distribution of benthic biological habitats. This approach includes a method of deriving statistical features from backscatter angular response curves created from MBES data collated within homogeneous regions of a backscatter mosaic. Using the RF algorithm we assess the relative importance of each variable in order to optimise the classification process and simplify models applied. The results showed that the inclusion of the angular response features in the classification process improved the accuracy of the final habitat maps from 88.5% to 93.6%. The RF algorithm identified bathymetry and the angular response mean as the two most important predictors. However, the highest classification rates were only obtained after incorporating additional features derived from bathymetry and the backscatter mosaic. The angular response features were found to be more important to the classification process compared to the backscatter mosaic features. This analysis indicates that integrating angular response information with bathymetry and the backscatter mosaic, along with their derivatives, constitutes an important improvement for studying the distribution of benthic habitats, which is necessary for effective marine spatial planning and resource managemen

Hydrologic landscape regionalisation using deductive classification and random forests

Landscape classification and hydrological regionalisation studies are being increasingly used in ecohydrology to aid in the management and research of aquatic resources. We present a methodology for classifying hydrologic landscapes based on spatial environmental variables by employing non-parametric statistics and hybrid image classification. Our approach differed from previous classifications which have required the use of an a priori spatial unit (e.g. a catchment) which necessarily results in the loss of variability that is known to exist within those units. The use of a simple statistical approach to identify an appropriate number of classes eliminated the need for large amounts of post-hoc testing with different number of groups, or the selection and justification of an arbitrary number. Using statistical clustering, we identified 23 distinct groups within our training dataset. The use of a hybrid classification employing random forests extended this statistical clustering to an area of approximately 228,000 km2 of south-eastern Australia without the need to rely on catchments, landscape units or stream sections. This extension resulted in a highly accurate regionalisation at both 30-m and 2.5-km resolution, and a less-accurate 10-km classification that would be more appropriate for use at a continental scale. A smaller case study, of an area covering 27,000 km2, demonstrated that the method preserved the intra- and inter-catchment variability that is known to exist in local hydrology, based on previous research. Preliminary analysis linking the regionalisation to streamflow indices is promising suggesting that the method could be used to predict streamflow behaviour in ungauged catchments. Our work therefore simplifies current classification frameworks that are becoming more popular in ecohydrology, while better retaining small-scale variability in hydrology, thus enabling future attempts to explain and visualise broad-scale hydrologic trends at the scale of catchments and continents

Fish species richness is associated with the availability of landscape components across seasons in the Amazonian floodplain

Understanding environmental biodiversity drivers in freshwater systems continues to be a fundamental challenge in studies of their fish assemblages. The present study seeks to determine the degree to which landscape variables of Amazonian floodplain lakes influences fish assemblages in these environments. Fish species richness was estimated in 15 Amazonian floodplain lakes during the high and low-water phases and correlated with the areas of four inundated wetland classes: (i) open water, (ii) flooded herbaceous, (iii) flooded shrubs and (iv) flooded forest estimated in different radius circular areas around each sampling site. Data were analyzed using generalized linear models with fish species richness, total and guilds as the dependent variable and estimates of buffered landscape areas as explanatory variables. Our analysis identified the significance of landscape variables in determining the diversity of fish assemblages in Amazonian floodplain lakes. Spatial scale was also identified as a significant determinant of fish diversity as landscape effects were more evident at larger spatial scales. In particular, (1) total species richness was more sensitive to variations in the landscape areas than number of species within guilds and (2) the spatial extent of the wetland class of shrubs was consistently the more influential on fish species diversity

Estimates of Heterozostera tasmanica, Zostera muelleri and Ruppia megacarpa distribution and biomass in the Hopkins Estuary, western Victoria, by GIS

Knowledge of the spatial arrangement of the seagrass distribution and biomass within the Hopkins Estuary is an essential step towards gaining an understanding of the functioning of the estuarine ecosystem. This study marks the first attempt to map seagrass distribution and model seagrass biomass and epiphyte biomass along depth gradients by the use of global positioning system (GPS) and geographical information system (GIS) technologies in the estuary. For mapping seagrass in small estuaries, ground-surveying the entire system is feasible. Three species of seagrasses, Heterozostera tasmanica (Martens ex Aschers), Zostera muelleri (Irmisch ex Aschers) and Ruppia megacarpa (Mason), were identified in the Hopkins Estuary. All beds investigated contained a mixed species relationship. Three harvest techniques were trialed in a pilot study, with the 25 &times; 25-cm quadrat statistically most appropriate. Biomass of seagrasses and epiphytes was found to vary significantly with depth, but not between sites. The average estimate of biomass for total seagrasses and their epiphytes in the estuary in January 2000 was 222.7 g m&ndash;2 (dry weight). Of the total biomass, 50.6% or 112.7 g m&ndash;2 (dry weight) was contributed by seagrasses and 49.4% of the biomass (110.0 g m&ndash;2) were epiphytes. Of the 50.6% of the total biomass represented by seagrasses, 39.3% (87.5 g m&ndash;2) were leaves and 11.3% (25.2 g m&ndash;2) were rhizomes. The total area of seagrasses present in the Hopkins Estuary was estimated to be 0.4 &plusmn; 0.005 km2, with the total area of the estuary estimated to be 1.6 &plusmn; 0.02 km2 (25% cover). The total standing crop of seagrasses and epiphytes in the Hopkins Estuary in January 2000 was estimated to be 102.3 &plusmn; 57 t in dry weight, 56% (56.9 &plusmn; 17 t, dry weight) seagrasses and 44% (45.4 &plusmn; 19 t, dry weight) epiphytes. Of the seagrass biomass, 39% (39.7 &plusmn; 13 t, dry weight) was contributed by leaves and 17% (17.3 &plusmn; 7 t, dry weight) by rhizomes.<br /

Presence of fish on the shallow flooded margins of a small intermittently open estuary in South Eastern Australia under variable flooding regimes

Shallow water habitats within estuarine systems are believed to be important areas for small fish. While a wide variety of shallow habitats have been studied, the land that becomes inundated by the damming effect after the closure of intermittently open mouths has previously been overlooked. Fish were sampled monthly from both the main channel and flood zone of an intermittently open estuary between July 2004 and June 2005 using minifyke nets during the day and at night. A total of 7,787 fish were collected during the study representing 13 species and 11 families. Philypnodon grandiceps was the most abundant species and, together with Atherinosoma microstoma, Pseudogobius olorum, and Galaxias maculatus, made up 94% of the total catch. Inundation of the flood zone occurred in two discrete forms associated with mouth condition, which consisted of sporadic flooding while the mouth was open, to long-term flooding for 6 months after its closure. Large numbers of fish were captured on the flood zone, which included nine species; however, A. microstoma dominated the catch. A distinct shift in the flood zone fish assemblage occurred between the two mouth conditions, which is likely associated with changes in hydro-period and food availability of the flood zone and physico-chemical parameters in the main channel. There was no longitudinal variation in the fish assemblage in both the main channel and flood zone; similarly, the diel period was found to have little effect on the fish assemblage. The total catch per unit effort did not vary across seasons and suggests that fish abundance within the estuary is stable throughout the year. Unlike other estuarine systems where shallow water fish assemblages may be structured by variations in tide and elevation within the Surrey, freshwater inflow and, more importantly, mouth condition appear to have the greatest influence in composition of the shallow water flood zone fish assemblage of intermittently open estuaries.<br /

Biology and commercial exploitation of the estuarine catfish, Cnidoglanis macrocephalus (Valenciennes) in South Western Australia with emphasis on the seasonally closed Wilson Inlet

Wilson Inlet is a seasonally closed estuary on the southern coast of Western Australia. It comprises a large basin (48 km^2), which is fed by two main tributary rivers and opens to the ocean by a narrow 1 km inlet channel. The sand bar which forms across the mouth of the estuary during dry periods is artificially breached when water levels reach 1.015 m Australian Height Datum. The length of time the estuary is open to the sea, which ranges from about two to 11 months, is related to the time of opening, i.e. the earlier the opening (which corresponds to high winter fresh water build up), the longer the bar remains breached. Samples of the estuarine catfish Cnidoglanis macrocephalus were collected by gill net and beach seines from the basin of Wilson Inlet in each month between September 1987 and April 1989. Cnidoglanis macrocephalus is a benthic carnivore, feeding mainly on molluscs, crustaceans and polychaetes. Diet changed from soft bodied prey {e.g. crustaceans, mytilids, nereids and gastropods) to robust bivalves {e.g. tellinids and venerids) with increasing body size and it also changed with season. Spawning occurred within the estuary, predominantly between mid-spring (October) and mid-summer (January), with peak spawning activity late November and early December. Sexual maturity was typically first reached at an average total length of 425 mm, at which size the fish were nearing the end of the third year of life. The eggs of C. macrocephalus were deposited in burrows and the males subsequently guarded both the eggs and larvae. While the growth of C. macrocephalus in Wilson Inlet was more rapid than in a nearby inshore marine area, it was similar to that in the Swan Estuary on the lower west coast of Western Australia further to the north. Commercial catches of C. macrocephalus in Wilson Inlet rose markedly from an annual average of 34,89 kg between 1976 and 1979 to 58,431 kg between 1985 and 1989. During these two periods, the percentage contribution of C. macrocephalus catches in Wilson Inlet to the total catch of this species in Western Australia increased from 15.6 to 46.0%. Commercial catches in Wilson Inlet varied seasonally, being greatest in spring and autumn and lowest during winter. They also varied markedly among years, with values being high in 1975 and 1986 (60,000 to 80,000 kg) and low between 1977 and 1983 (<35,000 kg). The total lengths and numbers of C. macrocephalus caught in the closed and open fishing waters of Wilson Inlet, using a gill net comprising a wide range of mesh sizes, were recorded. These data were then compared with those obtained for the commercial fishery. The results strongly indicate that (I) the density and percentage contribution of large fish are lower in open than in closed fishing waters, (II) female fish were more readily caught than male fish and (III) the minimum legal mesh size and minimum legal length for C. macrocephalus should be increased to prevent fish being caught before they reached sexual maturity