Suchergebnisse

Understanding the habitat requirements of a species is critical for effective conservation-based management. In this study, we investigated the influence of forest structure on the distribution of the yellow-footed antechinus (Antechinus flavipes), a small dasyurid marsupial characteristic of dry forests on the inland side of the Great Dividing Range, Australia. Hair-sampling tubes were used to determine the occurrence of A. flavipes at 60 sites stratified across one of the largest remaining tracts of dry box–ironbark forest in south-eastern Australia. We considered the role of six potential explanatory variables: large trees, hollow-bearing trees, coppice hollows, logs, rock cover and litter. Logistic regression models were examined using an information-theoretic approach to determine the variables that best explained the presence or absence of the species. Hierarchical partitioning was employed to further explore relationships between occurrence of A. flavipes and explanatory variables. Forest structure accounted for a substantial proportion of the variation in occurrence of A. flavipes between sites. The strongest influence on the presence of A. flavipes was the cover of litter at survey sites. The density of hollow-bearing trees and rock cover were also positive influences. The conservation of A. flavipes will be enhanced by retention of habitat components that ensure a structurally complex environment in box–ironbark forests. This will also benefit the conservation of several threatened species in this dry forest ecosystem.

Most studies of habitat use by small mammals rely on data from trapping grids. Such studies pertain to habitat use by individuals, which may not reflect population-level requirements. To meet the challenge of landscape change, it is important to understand habitat use by populations across large geographic areas. We surveyed small mammals in 48 forest remnants across a 300 km2 study area, to investigate the influence of vegetation heterogeneity on regional distributions. Information-theoretic techniques were used to evaluate models of vegetation associations. Richness of native mammals was influenced by vegetation condition: disturbed sites supported fewer species. Models for individual species showed the agile antechinus, Antechinus agilis, to prefer structurally diverse forest vegetation, the long-nosed potoroo, Potorous tridactylus, to favour mesic shrub communities, the bush rat, Rattus fuscipes, to prefer complex low cover regardless of composition, the swamp rat, Rattus lutreolus, to favour reduced canopy cover, and the house mouse, Mus domesticus, to prefer disturbed vegetation. To satisfy the needs of all native species, a mosaic of natural vegetation is required. Degradation and simplification of forest vegetation have detrimental consequences. These results highlight the need to consider habitat quality, together with more traditional biogeographic variables, when investigating factors influencing patch occupancy by native fauna in modified landscapes.

The rate and spatial scale at which natural environments are being modified by human land-uses mean that a regional or national perspective is necessary to understand the status of the native biota. Here, we outline a landscape-based approach for using data from the 'New Atlas of Australian Birds' to examine the distribution and status of avifauna at a regional scale. We use data from two bioregions in south-east Australia – the Gippsland Plain and the Strzelecki Ranges (collectively termed the greater Gippsland Plains) – to demonstrate this approach. Records were compiled for 57 landscape units, each 10′ latitude by 10′ longitude (~270 km2) across the study region. A total of 165 terrestrial bird species was recorded from 1870 'area searches', with a further 24 species added from incidental observations and other surveys. Of these, 108 species were considered 'typical' of the greater Gippsland Plain in that they currently or historically occur regularly in the study region. An index of species 'occurrence', combining reporting rate and breadth of distribution, was used to identify rare, common, widespread and restricted species. Ordination of the dataset highlighted assemblages of birds that had similar spatial distributions. A complementarity analysis identified a subset of 14 landscape units that together contained records from at least three different landscape units for each of the 108 'typical' species. When compared with the 40 most common 'typical' species, the 40 least common species were more likely to be forest specialists, nest on the ground and, owing to the prevalence of raptors in the least common group, take prey on the wing. The future status of the terrestrial avifauna of the greater Gippsland Plains will depend on the extent to which effective restoration actions can be undertaken to ensure adequate representation of habitats for all species, especially for the large number of species of conservation concern.

There is widespread concern about population decline in a number of woodland-dependent birds in southern Australia. Of all declining species, approximately half forage on the ground. This study examined the avifaunal assemblages of temperate woodlands of the Northern Plains, Victoria, to investigate the importance of woodland habitats for ground-foraging species. Four main types of woodland were surveyed (white cypress-pine, black box, grey box and river red gum) and, in total, 89 bird species were detected. All four woodland types differed in habitat structure and, in turn, supported significantly different avifaunal assemblages. Forty of the 89 species (45%) foraged, at least in part, on the ground. Species richness and abundance of ground-foragers differed significantly between woodland types, being highest in white cypress-pine and black box. There was a greater richness of ground-foragers during the breeding than non-breeding season, but abundance did not vary seasonally. Overall, ground-foraging birds comprised a greater proportion of species (>55%) and individuals (>60%) in white cypress-pine and black box woodland than in grey box and river red gum (42–48% of species, <50% individuals). Those ground-foragers regarded as declining also occurred in greatest richness in white cypress-pine woodlands, one of the most depleted habitats in the region. The lowest richness of 'declining' ground-foraging species was in river red gum woodland, the most widespread woodland type. Throughout Australia, the proportion of ground-foraging species in bird assemblages tends to be greater in temperate, semi-arid or arid woodlands than in moist forests and rainforests. However, in many regions woodland habitats are severely depleted and their open ground layer is particularly vulnerable to degradation. The extent of suitable habitat for ground-foraging birds in temperate woodlands may be much less than is apparent from current measures of tree cover. Sustainable management of drier (non-riverine) temperate woodlands is required to conserve this important element of the Australian avifauna.

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.

The squirrel glider (Petaurus norfolcensis) occurs in forests and woodlands in eastern Australia. In Victoria it is now largely restricted to small, fragmented areas and is considered endangered. In this study, the time-budget, feeding behaviour and related habitat use of the squirrel glider were investigated in a linear remnant of roadside vegetation near Euroa, Victoria. Timed observations of three males and three females, fitted with radio-collars, were made in each of four seasons. Gliders were observed for a total of 53.2 h, during which they devoted 72% of time to foraging activities. Grooming accounted for 16% of observation time. Exudates associated with homopterous insects were the primary food items consumed throughout the year. Arthropods, nectar and pollen, and Acacia gum formed the remainder of the diet. The proportion of time devoted to harvesting these food items showed marked seasonal variation. The primary dependence on homopterous insect exudates in this study area contrasts with other investigations at sites of greater floristic diversity where nectar and pollen were the most important dietary resources. This highlights the need to obtain ecological information from the range of habitats occupied by a species. Large trees are a vital habitat component of remnant linear vegetation in this study area, providing gliders with critical foraging resources. Retention of such trees is essential for the longevity of glider populations.

The conservation of roosting and nesting resources is of critical concern for many hollow-dependent species around the world. We investigated the nest-tree requirements of the threatened brush-tailed phascogale (Phascogale tapoatafa) in a highly cleared agricultural landscape in south-eastern Australia. We documented the physical characteristics of selected nest trees and describe the spatial and temporal patterns of nest-tree use as revealed by radio-tracking. Nine phascogales (seven females, two males) were radio-tracked between March and July 1999 in an area where most woodland habitat is confined to linear strips along roads and streams or small patches and scattered trees in cleared farmland. Female phascogales were monitored for 13–35 days over periods of 5–15 weeks and two males were monitored for 2 and 9 days respectively. A total of 185 nest-tree fixes was collected and all nests occupied by phascogales were in standing trees. Eighty-three nest trees were identified, ranging in diameter at breast height (dbh) from 25 to 171 cm, with a mean dbh for the trees used by each individual phascogale of >80 cm. Phascogales did not discriminate between canopy tree species in selecting nest trees, but showed highly significant selection for trees in the largest size class. All individuals used multiple nest trees, with the seven females occupying an average of 11.4 nest trees from a mean of 25 diurnal locations. The number of nest trees continued to increase throughout the study, suggesting that more would be identified during a longer or more intensive study. Occupied nest trees were located throughout each individual's home range, highlighting the importance of a continuous spatial distribution of suitable nest trees across the landscape. Nest trees were also located in adjacent farmland up to 225 m from roadside vegetation, demonstrating the value that scattered clumps and even single trees in farmland can have for wildlife conservation.

Nine phascogales (7 females, 2 males) were radio-tracked between March and
July 1999 to investigate the spatial organisation of this species in spatially
limited habitat near Euroa, Victoria. In this area, approximately 3.6%
of the original woodland vegetation remains after 150 years of agricultural
clearing. Most wooded habitat is confined to narrow linear strips along roads
and streams. However, these remnants are on fertile soils and, because they
have not experienced intensive harvesting, the density of large old trees is
over 10 times that found in nearby State Forests and Parks. Female phascogales
were monitored for 13–38 days over periods of 5–15 weeks. The size
of home ranges of females was 2.3–8.0 ha, and averaged 5.0 ha. This
value is one-eighth the mean home-range size previously recorded for the
species in contiguous forest in Victoria. All individuals used multiple nest
trees, with nests generally located in trees >80 cm diameter at breast
height. Although fragmented and spatially limited, the stands of large old
trees on productive soils near Euroa provide a network of well connected,
high-quality habitat for phascogales. The relatively dense population of
phascogales in these remnants suggests that prior to agricultural clearing and
timber harvesting, phascogales may have been much more common in Victoria than
at present.

Context Landscape management and restoration in rural environments is frequently driven by community groups, who often use 'flagship' species to generate broader engagement. In south-eastern Australia, installation of nest boxes for hollow-dependent fauna is undertaken by many groups. Monitoring the outcomes of such projects offers opportunities for citizen science. Aims The aim of the present study was to report on a community-led project to install and monitor nest boxes to enhance the conservation of a threatened species, the brush-tailed phascogale (Phascogale tapoatafa), and to investigate the extent of nest box use, factors influencing use, changes in use through time, and the effectiveness of nest boxes as a monitoring tool. Methods A community group installed 450 nest boxes across 150 sites to monitor and provide habitat for the brush-tailed phascogale. Of these, 102 sites were stratified in relation to: (1) geographic sub-region; (2) forest patch size; and (3) topographic position. Nest boxes were inspected five times over 8 years. We modelled factors influencing nest box use at the tree, site, and landscape level. We compared nest box data with data from camera traps at 50 sites to assess their value as a monitoring tool. Key results In any given survey, up to 6% of nest boxes had individuals present and up to 22% had evidence of use by the brush-tailed phascogale. There was greater use of nest boxes when installed on 'stringybark' type trees than 'box' and 'gum-barked' species. Nest box use was greater for sites on forest slopes than in gullies, and use varied between years. Surveys using remote cameras were more effective at detecting phascogales than monitoring nest boxes. Conclusions Nest box monitoring can provide insights into the distribution and habitat requirements of hollow-dependent species, and engage the community in citizen science. Elements that enhance community-led monitoring include scientific input to project design, collecting data in a consistent manner, allocating sufficient time for data curation, engaging people invested in project outcomes, maintaining good relationships with stakeholders, and sharing data for analysis. Implications Collaboration between scientists and community groups can be of benefit to both parties. However, to maximise scientific and conservation outcomes there must be effective engagement and adequate resourcing for project coordination.

Context. Designing an appropriate survey protocol requires understanding of how capture rates of target species may be influenced by factors other than on-ground abundance, such as weather conditions or seasonality. This is particularly relevant for ectotherms such as reptiles, as activity can be affected by environmental conditions such as ambient temperature.
Aims. The present study examines factors affecting capture success of reptiles in semi-arid environments of southern Australia, and addresses the following two main questions: (1) what is the influence of weather and seasonal factors on capture rates of reptiles, and (2) what are the implications for developing an effective protocol for reptile surveys?
Methods. We surveyed reptiles using pitfall traps in spring and summer of 2006/07 and 2007/08 at sites (n = 280) throughout the Murray Mallee region of south-eastern Australia. We used mixed-effect regression models to investigate the influence of seasonal and weather-related variables on species' capture success.
Key results. Total captures of reptiles, and the likelihood of capture of 15 reptile species, increased with rising daily temperature. Greater numbers of individual species were captured during spring than in summer, even though temperatures were cooler. This probably reflects greater levels of activity associated with breeding. Several species were more likely to be captured when maximum or minimum daily temperatures exceeded a certain level (e.g. Lerista labialis, Delma australis, Nephrurus levis). Other factors, such as rainfall and moon phase, also influenced capture success of some species.
Conclusions. Surveys for reptiles in semi-arid environments are likely to capture the greatest diversity of species on warm days in late spring months, although surveys on hot days in summer will enhance detection of particular species (e.g. Morethia boulengeri, Varanus gouldii). We recommend trapping during periods with maximum temperatures exceeding 25–30°C and minimum overnight temperatures of 15°C. Finally, trapping during rainfall and full-moon events will maximise chances of encountering species sensitive to these variables (blind snakes and geckoes).
Implications. Selecting the most favourable seasonal and weather conditions will help ensure that reptile surveys maximise the likelihood of capturing the greatest diversity of reptiles, while minimising trap-effort required.

Context. Wildfire is a major driver of the structure and function of mallee eucalypt- and spinifex-dominated landscapes. Understanding how fire influences the distribution of biota in these fire-prone environments is essential for effective ecological and conservation-based management.
Aims. We aimed to (1) determine the effects of an extensive wildfire (118 000 ha) on a small mammal community in the mallee shrublands of semiarid Australia and (2) assess the hypothesis that the fire-response patterns of small mammals can be predicted by their life-history characteristics.
Methods. Small-mammal surveys were undertaken concurrently at 26 sites: once before the fire and on four occasions following the fire (including 14 sites that remained unburnt). We documented changes in small-mammal occurrence before and after the fire, and compared burnt and unburnt sites. In addition, key components of vegetation structure were assessed at each site.
Key results. Wildfire had a strong influence on vegetation structure and on the occurrence of small mammals. The mallee ningaui, Ningaui yvonneae, a dasyurid marsupial, showed a marked decline in the immediate post-fire environment, corresponding with a reduction in hummock-grass cover in recently burnt vegetation. Species richness of native small mammals was positively associated with unburnt vegetation, although some species showed no clear response to wildfire.
Conclusions. Our results are consistent with the contention that mammal responses to fire are associated with their known life-history traits. The species most strongly affected by wildfire, N. yvonneae, has the most specific habitat requirements and restricted life history of the small mammals in the study area. The only species positively associated with recently burnt vegetation, the introduced house mouse, Mus domesticus, has a flexible life history and non-specialised resource requirements.
Implications. Maintaining sources for recolonisation after large-scale wildfires will be vital to the conservation of native small mammals in mallee ecosystems.

Context Seasonal migration and movements of bats have important implications for their conservation. The southern bent-winged bat (Miniopterus orianae bassanii), a critically endangered cave-dwelling taxon in Australia, has been described as undertaking regional-scale migration between maternity and non-breeding caves. Aims To describe the seasonal cycle of movements by the southern bent-winged bat, including migration and congregation events of different sex- and age-classes in the population. Methods We tagged a total of 2966 southern bent-winged bats with passive integrated transponder (PIT) tags. Antennas were used to detect bats in flight at a major maternity cave and a key non-breeding cave in south-east South Australia, from January 2016 to August 2019. We used capture–resight histories to visualise population patterns and model the daily encounter probability for each sex- and age-class at the respective roost sites. Key results Bats congregated at the maternity cave for most of the year, with different seasonal patterns among sex- and age-classes. Seasonal movements were associated with behaviour over winter months: most of the population dispersed from the maternity cave from May and a staged return occurred among population classes from July through September. A previously undescribed movement occurred in adult females and juveniles each year: these classes left the maternity cave in late summer, when juveniles became independent, and returned in early mid-autumn, later undertaking winter dispersal. Complex underlying movements of individuals occurred throughout the year, with individuals able to fly 72 km between roosting caves in just a few hours. Conclusions Seasonal movements are a key aspect of the life history of this taxon. The newly reported movement of adult females and juveniles conforms to the maternal guidance hypothesis, whereby mothers guide their young to suitable non-breeding caves and hibernation sites. In addition to seasonal movements, some individuals moved 72 km between caves multiple times over short time periods, including on successive nights. This 72-km overnight flight distance more than doubles the previous distance used to inform management buffer zones. Extended congregation of bats at the maternity cave highlights resource limitation in the surrounding area as a potential threat to this population. Implications The dynamic nature of the population has implications for the management of emerging risks, including mortality at windfarms and potential rapid spread of the exotic white-nose syndrome.

Fire has been a source of global biodiversity for millions of years. However, interactions with anthropogenic drivers such as climate change, land use, and invasive species are changing the nature of fire activity and its impacts. We review how such changes are threatening species with extinction and transforming terrestrial ecosystems. Conservation of Earth's biological diversity will be achieved only by recognizing and responding to the critical role of fire. In the Anthropocene, this requires that conservation planning explicitly includes the combined effects of human activities and fire regimes. Improved forecasts for biodiversity must also integrate the connections among people, fire, and ecosystems. Such integration provides an opportunity for new actions that could revolutionize how society sustains biodiversity in a time of changing fire activity. ; The workshop leading to this paper was funded by the Centre Tecnològic Forestal de Catalunya and the ARC Centre of Excellence for Environmental Decisions. L.T.K. was supported by a Victorian Postdoctoral Research Fellowship (Victorian Government), a Centenary Fellowship (University of Melbourne), and an Australian Research Council Linkage Project Grant (LP150100765). A.R. was supported by the Xunta de Galicia (Postdoctoral Fellowship ED481B2016/084-0) and the Foundation for Science and Technology under the FirESmart project (PCIF/MOG/0083/2017). A.L.S. was supported by a Marie Skłodowska-Curie Individual Fellowship (746191) under the European Union Horizon 2020 Programme for Research and Innovation. L.R. was supported by the Australian Government's National Environmental Science Program through the Threatened Species Recovery Hub. L.B. was partially supported by the Spanish Government through the INMODES (CGL2014-59742-C2-2-R) and the ERANET-SUMFORESTS project FutureBioEcon (PCIN-2017-052). This research was supported in part by the U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station.