Conservation and management of hydromyine rodents in Victoria, Australia

Of the 15 species of native rodents recorded from Victoria, Australia, six became extinct within 70 years of European settlement, and two of the remaining nine are classified as ‘threatened’ and four are classified as ‘near threatened’. Thus, only three species are considered to be adequately conserved. This represents one of the most dramatic mammalian species declines recorded in Australia. All the threatened species belong to the subfamily Hydromyinae, the Australian ‘old endemics’. Of the extinct species, four were recorded only from the semi-arid north-west of the state and two from dry woodlands in the central and southern regions. The two  endangered species are the smoky mouse, which has a disjunct distribution from near-coastal to sub-alpine habitats, and the New Holland mouse, which is the most geographically restricted species. Discovered in Victoria only in 1970, it has become extinct at several locations and is the subject of a major recovery program that includes captive breeding and reintroduction. Conservation protocols and practices for Victoria’s native rodents are implemented under state legislation, but lack of basic ecological information makes their conservation a difficult task.

The role of Riparian habitats in forest mosaics in promoting Avifauna at the landscape scale

The importance of riparian habitats to bird communities is well documented internationally, however the value of these habitats in largely intact landscapes is less well understood, particularly in Australia. Thirty paired riparian and adjacent non-riparian sites were selected within extensive forest mosaics of the Victorian Central Highlands and were surveyed over a two year period. Bird assemblages occurring within riparian habitats supported a significantly greater richness, abundance and diversity of species. These assemblages were also found to have species compositions significantly different from those occurring at adjacent non-riparian sites separated by a distance of approximately 750 m. Differences were attributed to a suite of distinctive species and significant contrasts in the densities of a range of species that occur in both habitat types. At the landscape level, there was a strong patterning of the avifauna centred on riparian habitats. Bird assemblages typically comprised four distinct suites of species: 1. species widespread in forests and woodlands of southeastern Australia; 2. riparian associated species (wet forest intruders); 3. riparian selective species, and; 4. riparian avoiding species. Both physiognomic and floristic differences between riparian and adjacent non-riparian habitats appear to drive responses in the structure of bird communities. There exists a distinctiveness and variability among the range of vegetation types and associated bird assemblages occurring throughout the forest matrix, including in riparian habitats. The occurrence of complimentary bird assemblages throughout the landscape mosaic highlights the importance of whole landscape planning for avifauna conservation.

Conservation management and diets of Powerful Owls (Ninox strenua) in outer urban Melbourne, Australia

The Powerful Owl Ninox strenua is Australia’s largest owl, and is mainly found east of the Great Dividing Range on the mainland in tall-open forests. The species is considered rare, both nationally and in the State of Victoria; and threatened in the Greater Melbourne area. Recovery plans for the future conservation management of N. strenua are being prepared in 2 states.

Historically, Powerful Owls have been thought to require large homes ranges (about 1000 ha per pair) in suitable old-growth forest, which provides nest hollows for the owls and their arboreal marsupial prey. Recent research, however, has found N. strenua may be more numerous and breed more successfully in a wider range of habitats than previously believed. In particular, the birds have been found living in forests and woodlands within the greater metropolitan areas of cities. The most extreme case is where a nest tree has been found within 800m of urban settlement and 6km from the centre of Brisbane.

In this paper we report on the diet, habitat use, and conservation management by a number of breeding pairs of owls in outer urban Melbourne. Study sites range from a relatively undisturbed rainforest habitat 80km from central Melbourne, through dry sclerophyll, eucalyptus-dominated open forest with some disturbance to a site 8km from central Melbourne in highly disturbed urban parkland.

Diets of the families of owls were determined by analyzing remains in regurgitated pellets. The data confirm that arboreal marsupials constitute the major prey items, especially the Common Ringtail Possum Pseudocheirus peregrinus. There were differences in diets depending on the availability of prey species, which suggest a level of opportunism not previously suspected. Our study is also the first to confirm the owls capture adult Common Brushtail Possums Trichosurus vulpecula (15% of pellets containing the remains of this large opossum have bones of mature adults at 1 site) and thus take prey up to two and a half times their own weight. As well our data suggest Powerful Owls are not restricted to hollow-dwelling prey, as in some sites the marsupials rested during the day either in leafy nests called dreys (P. peregrinus) or in house roofs (T. vulpecula).

In the most heavily disturbed sites, breeding success has been reduced, and we have evidence that in one particular year the young were eaten by one of the parents. This followed construction of a bicycle track under the nest during the breeding season. Recommendations are made for the future conservation and habitat management of Powerful Owls in the Yarra Valley corridor.

Foraging behaviour and habitat utilisation of Australasian gannets determined using GPS loggers

Australasian gannets (Morus serrator) breed in the cool temperate waters of south-eastern Australia and also at several localities around New Zealand, where they are a major marine predator feeding on commercially-exploited pelagic fish. This study investigated the foraging behaviour and habitat utilization of gannets at Pope’s Eye Marine Reserve during the 2005-2005 breeding period using GPS-depth-loggers. GPS data were recorded for a total of 45 foraging trips from 20 individuals. Gannets were found to forage at average maximum distances of 52.7 km (± 29.6 km) from the colony, with total foraging path lengths of 177.1 km (± 93.4 km) and foraging trip durations of 16.5 h (± 9.9 h). During foraging trips gannets spent on average 31.5% (± 11.4) of the time flying at an average flight speed of 47.3 km h-1 (± 2.9 km h-1). Gannets made an average of 39.8 (± 35.2) dives per trip and 3.8 (± 5.6) dives per daylight hour. Dives had an average depth of 3.5 m (± 1.1 m) and a mean maximum depth of 7.0 m (± 3.0 m), lasting for a mean dive duration of 5.3 sec (± 1.3 sec). Gannets foraged predominantly in shallow coastal waters and there was some evidence for foraging site fidelity. Considerable individual variation in foraging strategies was also observed. The results highlight the potential of GPS technology to reveal the fine-scale foraging behaviour of marine predators, thereby improving our understanding the interaction between marine predator populations, commercially exploited fish stocks and the marine environment.

Milk consumption, body composition and pre-weaning growth rates of Australian fur seal

Pre-weaning growth rates, body composition, milk consumption and mass gain efficiency were measured in Australian fur seal Arctocephalus pusillus doriferus pups born in two consecutive breeding periods. Australian fur seals have the highest birth mass of any fur seal species (male 8.3 kg; female 7.2 kg). While their absolute pre-weaning growth rate (male 62 g·day⁻¹; female 53 g·day⁻¹) is similar to that of other temperate latitude fur seals, they have the longest birth-mass doubling time of any otariid species (134–136 days). Daily milk consumption increased from 400 g·day−1 (5 MJ·day−1) after birth to 675 g·day⁻¹ (13.7 MJ·day⁻¹) at age 210 day. However, mean mass-specific milk consumption (41 g·kg⁻¹) is substantially lower than in other otariid species (58–70 g·kg⁻¹) and, combined with a low mass gain efficiency (0.12 g·g⁻¹), contributes to the low mass-specific growth rates observed. There were no significant differences in either absolute or mass-specific milk consumption between the sexes. Significant differences, however, were found between the sexes in the body composition of pups with females generally having larger body lipid stores than males for any given mass. Peak milk yield by Australian fur seal females is estimated at 0.60 MJkg−0.75, substantially less than in Antarctic fur seals. The low level of maternal energy transfer in Australian fur seals may reflect the relatively low marine productivity of their foraging areas.

Varicella infection : evidence for peak activity in summer months

This study aimed to identify seasonal variations in the presentation of primary varicella infection in susceptible patients in Victoria (a temperate region in south-east Australia) by analysing Victorian hospital admissions data and medical locum service data from the years preceding the introduction of a universally offered vaccination, complemented by available surveillance data from the neighbouring state, of South Australia. Contrary to the conventional assumption, which is based on observations in temperate regions elsewhere in the world, we found no consistent evidence of seasonal peaks during late winter and early spring for varicella infection in Victoria. This finding may have implications for prevention in temperate regions elsewhere in the world wherever estimations of local seasonal trends have been based on international experiences.

Using community-based monitoring with GIS to create habitat maps for a marine protected area in Australia

In recent years there has been an increase in community-based monitoring programmes developed and implemented worldwide. This paper describes how the data collected from such a programme could be integrated into a Geographic Information System (GIS) to create temperate subtidal marine habitat maps. A differential Global Positioning System was utilized to accurately record the location of the trained community-based SCUBA diver data. These georeferenced data sets were then used to classify benthic habitats using an aerial photograph and digitizing techniques. This study demonstrated that trained community-based volunteers can collect data that can be utilized within a GIS to create reliable and cost-effective maps of shallow temperate subtidal rocky reef systems.

Barriers to cross-fertilization between populations of a widely dispersed Polychaete species are unlikely to have arisen through gametic compatibility arms-races

Although there are theoretical reasons to suspect that gametic incompatibility may develop readily among populations of broadcast spawning marine invertebrates, there have been very few studies documenting geographic patterns of interpopulation incompatibility for any species. To address this we determined how successfully individuals of the intertidal serpulid polychaete, Galeolaria caespitosa, can cross-fertilize within and among populations from across temperate Australia. Fertilization assays revealed asymmetrical differences between very distantly located populations from different coasts, with near-complete incompatibility between eggs from Sydney with sperm from Adelaide, but the reverse cross (Adelaide eggs, Sydney sperm) was reasonably compatible. Although that pattern was congruent with a clear difference in Cytochrome B sequences between worms on the south and east coasts of Australia, we also detected some indication of interpopulation incompatibility within the genetic grouping on east coast, between two populations separated by only 220 km. We then assessed whether commonly proposed gametic compatibility arms-races could account for these patterns. Our results suggest reduced gametic compatibility may reduce a female's maximum fertilization potential, resulting in a cost to this potential mechanism for reducing polyspermy. Consequently, the apparently rapid development of reproductive barriers here seems unlikely to have been driven by arms-races involving sexual conflict over fertilization rate.

Regional faunal decline – reptile occurrence in fragmented rural landscapes of south-eastern Australia

Many species of reptiles are sedentary and depend on ground-layer habitats, suggesting that they may be particularly vulnerable to landscape changes that result in isolation or degradation of native vegetation. We investigated patterns of reptile distribution and abundance in remnant woodland across the Victorian Riverina, south-eastern Australia, a bioregion highly modified (>90%) by clearing for agriculture. Reptiles were intensively surveyed by pitfall trapping and censuses at 60 sites, stratified to sample small (<30 ha) and large (>30 ha) remnants, and linear strips of roadside and streamside vegetation, across the regional environmental gradient. The recorded assemblage of 21 species was characterised by low abundance and patchy distribution of species. Reptiles were not recorded by either survey technique at 22% of sites and at a further 10% only a single individual was detected. More than half (53%) of all records were of two widespread, generalist skink species. Multivariate models showed that the distribution of reptiles is influenced by factors operating at several levels. The environmental gradient exerts a strong influence, with increasing species richness and numbers of individuals from east (moister, higher elevation) to west (drier, lower elevation). Differences existed between types of remnants, with roadside vegetation standing out as important; this probably reflects greater structural heterogeneity of ground and shrub strata than in remnants subject to grazing by stock. Although comparative historical data are lacking, we argue that there has been a region-wide decline in the status of reptiles in the Victorian Riverina involving: (1) overall population decline commensurate with loss of >90% of native vegetation; (2) disproportionate decline of grassy dry woodlands and their fauna (cf. floodplains); and (3) changes to populations and assemblages in surviving remnants due to effects of land-use on reptile habitats. Many species now occur as disjunct populations, vulnerable to changing land-use. The status of reptiles in rural Australia warrants greater attention than has been given to date. Effective conservation of this component of the biota requires better understanding of the population dynamics, habitat use and dispersal capacity of species; and a commitment to landscape restoration coupled with effective ecological monitoring.

Ecosystem conservation in multi-tenure reserve networks : the contribution of land outside of publicly protected areas

Multi-tenure reserve networks have been developed as a mechanism to improve cross tenure management and protection of biodiversity, but also as a means of accounting for biodiversity assets managed for conservation outside of protected areas on public land. We evaluated the contribution of multi-tenure reserve networks to enhancing the comprehensiveness and representativeness of ecosystems in publicly protected areas, using three Australian case studies. All networks contributed to enhancing comprehensiveness and representativeness, but this contribution varied between networks and between components of those networks. Significantly, components on private land and "other public land" in all three networks greatly enhanced the protection of some ecosystems at a subregional scale. The Grassy Box Woodlands Conservation Management Network, in particular made a substantial contribution to conservation, with most components protecting remnants of an endangered and under-represented ecosystem. Multi-reserve conservation networks not only act to protect threatened and under-reserved ecosystems, but they also provide a mechanism to account for this protection. Thus, multi-tenure reserve networks have the potential to provide increased knowledge and understanding to conservation planning decision making processes.

Future landscapes in South-eastern Australia : the role of protected areas and biolinks in adaptation to climate change

The extent and rapidity of global climate change is the major novel threatening process to biodiversity in the 21 st century. Globally, numerous studies suggest movement of biota to higher latitudes and altitudes with increasing empirical -evidence emerging. As biota responds to the direct and consequent effects of climate change the potential to profoundly affect natural systems (including the reserve system) of south-eastern Australia is becoming evident. Climate change is projected to accelerate major environmental drivers such as drought, fire and flood regimes. Is the reserve system sufficient for biodiversity conservation under a changing climate? Australia is topographically flat, biologically mega-diverse with high species endemism, and has the driest and most variable climate of any inhabited continent. Whilst the north-south orientation and aftitude gradient of eastern Australia's forests and woodlands provides some resilience to projected climatic change, this has been eroded since European settlement, particularly in the cool-moist Bassian zone of the south-east. Following settlement, massive land-use change for agriculture and forestry caused widespread loss and fragmentation of habitats; becoming geriatric in agricultural landscapes and artificially young in forests. The reserve system persists as an archipelago of ecological islands surrounded by land uses of varying compatibility with conservation and vulnerable to global warming. The capacity for biota to adapt is limited by habitat availability. The extinction risk is exacerbated. Re-examination of earlier analysis of ecological connectivity through biolink zones confirms biolinks as an appropriate risk management response within a broader suite of measures. Areas not currently in the reserve system may be critical to the value and ecological function of biological assets of the reserve system as these assets change. Ecological need and the rise of ecosystem services, combined with changing socio-economic drivers of land-use and social values that supported the expansion of the reserve system, all suggest biolink zones represent a new, necessary and viable multi-functional landscape. This paper explores some of the key ecological elements for restoration within biolink zones (and landscapes at large) particularly through currently agricultural landscapes.

Trained community volunteers can collect useful data

Our experience suggests trained community voluteers can collect reliable habitat data that can be used to ground-truth habitat maps in a cost effective- manner. Without a basic understanding of the delineation of subtidal habitats, marine ecosystems cannot be managed effectively, and importantly the effects of climate change, protection or other human impacts cannot begin to be predicted

Field metabolic rate and body water turnover of the red fox (Vulpes vulpes) in Australia

We measured the daily energy expenditure of free-living red foxes Vulpes vulpes occupying a temperate region of New South Wales, Australia. Field metabolic rate (FMR) and body water turnover were estimated using doubly labelled water. In autumn, male body mass ranged from 5 to 6.1 kg (mean 5.6 kg) and their FMRs averaged 2328 kJ/day. Female body mass in autumn ranged from 4.9 to 6.6 kg (mean 5.4 kg) and their FMRs averaged 1681 kJ/day. Body water influx for males and females was 314 and 251 mL/day, respectively. Body composition of each fox was analysed after the field measurements and revealed a significant correlation between body water content, as estimated from tritiated water space, and body lipids (r² = 0.72). This supports the use of body water determination as a potentially non-destructive method to gauge body condition.

What drives long-distance movements in the nomadic Grey Teal Anas gracilis in Australia?

In contrast to northern temperate environments, where day length and temperature changes are obvious proximate cues for movement to resource-rich breeding habitats, the cues for movement used by birds in an often resource-poor, stochastic environment are less obvious. We recorded long-distance movements of 23 Grey Teal Anas gracilis using satellite telemetry for up to 879 days and examined the relationship between those movements and environmental factors, such as heavy rainfall and flooding, at the destination site. We identified 32 long-distance [> 150 km) movements that met our criterion for minimally interrupted flight between origin and destination. Thirteen of these flights coincided with rainfall and/or flooding events up to 1050 km from the origin. However, some ducks moved without any clear beneficial conditions at the destination onto small wetlands in regions with little surface water. The data suggest that there are two types of long-distance movement - ranging and directed. These flights occurred over distances up to 1200 km across the arid inland. The rates and distances of movement suggest that long-distance movements of Grey Teal entail high energy costs as in waterfowl elsewhere. We conclude that the proximate controls of directIn contrast to northern temperate environments, where day length and temperature changes are obvious proximate cues for movement to resource-rich breeding habitats, the cues for movement used by birds in an often resource-poor, stochastic environment are less obvious. We recorded long-distance movements of 23 Grey Teal Anas gracilis using satellite telemetry for up to 879 days and examined the relationship between those movements and environmental factors, such as heavy rainfall and flooding, at the destination site. We identified 32 long-distance (> 150 km) movements that met our criterion for minimally interrupted flight between origin and destination. Thirteen of these flights coincided with rainfall and/or flooding events up to 1050 km from the origin. However, some ducks moved without any clear beneficial conditions at the destination onto small wetlands in regions with little surface water. The data suggest that there are two types of long-distance movement – ranging and directed. These flights occurred over distances up to 1200 km across the arid inland. The rates and distances of movement suggest that long-distance movements of Grey Teal entail high energy costs as in waterfowl elsewhere. We conclude that the proximate controls of directed movements need not be very different from those of their temperate counterparts.ed movements need not be very different from those of their temperate counterparts.