Lizard distribution patterns in the Tumut fragmentation “Natural Experiment” in south-eastern Australia

Lizard distribution patterns were examined in a fragmented plantation landscape in south-eastern Australia. Regression modelling was used to relate ecological variables to (1) lizard species richness, (2) lizard species composition, and (3) the presence or abundance of selected lizard species. Ecological variables covered four broad domains that affect animals: climate, space, shelter and food availability.Lizard species richness was highest at mid-elevation sites, and at locations with a large amount of native forest within 1000 m. A major change in lizard species composition was associated with elevation, the proportion of native forest within 1000 m of a site, and the abundance of springtails. The change in species composition coincided with a range of individualistic responses to environmental conditions by different lizard species. For example, with respect to shelter availability, old logs were related to the garden skink Lampropholis guichenoti, shrubs were related to the delicate skink L. delicata, and rocks were related to the red-throated skink Bassiana platynota. The garden skink was most abundant at low elevations, the delicate skink was most likely to occur at intermediate elevations, and the mountain log skink Pseudemoia entrecasteauxii was most likely to occur at high elevations. The garden skink was most abundant in areas surrounded by little native forest, whereas Maccoy’s skink Nannoscincus maccoyi and Coventry’s skink Niveoscincus coventryi were more abundant or likely to occur in areas whose context was dominated by native forest.Because animal species may respond individualistically to gradients of climate, space, shelter and food availability, continuum theory (as developed for plant ecology) may be a useful complement to fragmentation theory to explain distribution patterns. To maintain lizard diversity in the study area, it will be important to maintain maximum habitat heterogeneity at the landscape and microhabitat scales. For species otherwise threatened by plantation development, large, fairly undisturbed areas of eucalypt forest will be particularly important.     

A survey design for monitoring the abundance of arboreal marsupials in the Central Highlands of Victoria

We describe a non-standard sample design for monitoring the abundance of arboreal marsupials in the montane ash forests of the Central Highlands of Victoria, south-eastern Australia. The survey design is based on overlapping and rotating sampling from a given population of sites—in this case 160 sites, each measuring 1 ha in size. Estimates of population sizes are obtained using a model-based statistical analysis. Results so far reveal considerable year-to-year variability in populations of Leadbeater's Possum (Gymnobelideus leadbeateri), the Mountain Brushtail Possum (Trichosurus cunninghamii), and the Greater Glider (Petauroides volans). There appears to be an initial decline in the numbers of Leadbeater's Possum, an increase in the Mountain Brushtail Possum and no change in the Greater Glider and the total number of arboreal marsupials. It will be possible report more substantive findings about long-term trends after several more years of the program. Relationships between current and past counts for Leadbeater's Possum and Mountain Brushtail Possum were very weak. This result appeared to be due to low levels of site fidelity for these two species.     

Longitudinal patterns in bird reporting rates in a threatened ecosystem: Is change regionally consistent?

Work in many parts of the world has discussed the decline of biodiversity in regions dominated by agriculture. We report the results of a major study documenting the longitudinal profiles of birds between 1998 and 2009 within 66 patches of temperate woodland in a heavily cleared and grazed agricultural region of south-eastern Australia. Many researchers have forecast the loss of bird biota from this region and others that also were formerly dominated by temperate woodland.We had sufficient high quality data to analyse the longitudinal profiles of reporting rates for 76 of the 116 individual bird species recorded in our 12-year study. Unexpectedly, only four of the 76 species analysed (5.6%) exhibited a significant negative linear decrease in reporting rate. More surprisingly, 32 (42.1%) exhibited a significant positive linear increase in reporting rate, including several taxa of conservation concern. These increases occurred despite a series of below-average rainfall years. Reporting rates were too low to formally model long-term trends in some other bird species widely considered to be of conservation concern such as the Diamond Firetail (Stagonopleura guttata) and Speckled Warbler (Chthonicola sagittata).Many authors have used functional (and other) groups to forecast bird species likely to be lost from Australia’s temperate woodlands. However, we found no clear links between life history attributes and long-term trend patterns of species.Our findings contrast with recent findings from other temperate woodland-dominated regions in eastern Australia where losses in bird populations have been documented. However, they parallel other investigations such as in central New South Wales. These similarities among, and differences between, studies suggest regional differences in temporal patterns in bird population dynamics. Many of the observed changes in reporting rates were positive and they provide hope that forecast future losses of a large proportion of existing temperate woodland bird assemblages in south-eastern Australia may not be realised uniformly in all regions.     

Field comparison of the interferon-gamma assay and the intradermal tuberculin test for the diagnosis of bovine tuberculosis

An extensive field comparison of the gamma interferon (IFN-gamma) assay and the single intradermal tuberculin test for the diagnosis of bovine tuberculosis was conducted in Australia. The specificity of the IFN-gamma assay was determined by testing more than 6000 cattle from tuberculosis-free herds and varied from 96.2% to 98.1%, depending on the cut-off point chosen to define a positive reactor. For the sensitivity trial, cattle from herds being de-populated because of bovine tuberculosis were examined with both assays. The sensitivity of the IFN-gamma assay was shown to be significantly higher than the single intradermal tuberculin test and varied from 76.8% to 93.6% depending on the method of interpretation. A maximum overall sensitivity of 95.2% was obtained by testing with the IFN-gamma and the tuberculin test in parallel. The superior sensitivity of the IFN-gamma assay and the ability to adjust the sensitivity of the system depending on the task involved, will provide the Australian Tuberculosis Eradication Campaign with a valuable additional test to enable it to accomplish its goals.     

Movement across woodland edges suggests plantations and farmland are barriers to dispersal

Landscape Ecology - The behavioural response of animals to edges between habitat patches and the matrix can influence population dynamics and species persistence in fragmented landscapes. We aimed...     

Old forest,new perspectives—Insights from the Mountain Ash forests of the Central Highlands of Victoria,south-eastern Australia

Old growth forest has become a major and increasingly prevalent research topic over the past two decades. However, there is no generic definition that can be applied uncritically to all forest types. This is because a precise definition of old growth is ecologically meaningful only when it is applied to a specific vegetation type. This is demonstrated in this paper using the Mountain Ash (Eucalyptus regnans) forests of the Central Highlands of Victoria, south-eastern Australia as a case study. These forests have been the target of extensive and intensive research over the past 25 years. That work has shown that a number of attributes of stand structure and composition can be crudely used to distinguish old growth forest from other age cohorts of Mountain Ash forest. However, it is not unusual for some of these characteristics also to be recorded in regrowth stands.     

Adaptive risk management for certifiably sustainable forestry

The past decade has seen a global surge in forest management certification, with over 200 million hectares of the world's forest now certified as sustainably harvested. Because forests are some of the most species-rich environments on earth and more than 90% of the world's forests occur outside formal protected area systems, forest management certification will be one of the pervasive influences on global biodiversity for the foreseeable future. We find that current forest certification schemes are largely deficient because they fail to demand: (i) measurable management objectives for biodiversity, (ii) formal risk assessment of competing management options that integrate impacts on biodiversity, (iii) monitoring that directly addresses management performance requirements and a clear plan for how monitoring information will be used to make better management decisions, and (iv) ongoing research targeted toward practices that enhance biodiversity in managed landscapes. We argue that the credibility of certification schemes hinges on their ability to dictate scientifically defensible management systems for biodiversity conservation. We present a framework for adaptive risk management (ARM) of biodiversity that is both responsibly proactive and diligently reactive and recommend its incorporation in all certification schemes. We highlight the need for substantial government and agency investment in fostering ARM.