Lefoe, M., Rendall, AR., McKinnon, F., Whisson, DA.
Habitat loss and degradation are two of the greatest threats to biodiversity conservation globally. In Australia, the incidence of wildfire and native forest logging contribute substantially to these processes and have been linked to reduced species diversity and abundance. Arboreal species such as the Yellow-bellied Glider (Petaurus australis), are thought to be susceptible to these disturbances due to their reliance on large patches of forest and hollow-bearing trees. We aimed to assess the impact of logging and wildfire on site occupancy by the Yellow-bellied Glider in Mountain Ash forest of the Central Highlands of Victoria. We deployed autonomous recording units for 14 nights at 70 sites and searched recordings for Yellow-bellied Glider vocalisations. Yellow-bellied Gliders were detected at 30% (N=21) of sites. Site occupancy increase with an increasing proportion of the landscape (within 400m of the recorder) that had not been logged within the last 100 years or burnt by wildfire in the last 10 years. Habitat disturbance caused by logging and fire therefore limit the site occupancy of Yellow-bellied Gliders and likely impact its conservation status. It is therefore critical that appropriate management of timber resources protects large patches of old-growth forest providing food resources and hollows, and the connectivity between large forest patches.
Whisson, DA., McKinnon, F., Lefoe, M., Rendall, AR.
Passive acoustic monitoring (PAM) is increasingly being used for the survey of vocalising wildlife species that are otherwise cryptic and difficult to survey. Our study aimed to develop PAM guidelines for detecting the Yellow-bellied Glider, a highly vocal arboreal marsupial that occurs in native Eucalyptus forests in eastern and south-eastern Australia. To achieve this, we considered the influence of background noise, weather conditions, lunar illumination, time since sunset and season on the probability of detecting vocalisations. We deployed Autonomous Recording Units (ARUs) at 43 sites in the Central Highlands of Victoria during two periods: spring/summer (October 2018 to January 2019), and autumn/winter (May to August 2019). ARUs were programmed to record for 11 hours from sunset for 14 consecutive days during each period. Background noise resulted from inclement weather (wind and rain) and masked vocalisations in spectrograms of the recordings, thus having the greatest influence on detection probability. Vocalisations were most common in the four hours after sunset. Rainfall negatively influenced detection probability, especially during the autumn/winter sampling period. Detection of Yellow-bellied Gliders with PAM requires deploying ARUs programmed to record for four hours after sunset, for a minimum of six nights with minimal inclement weather (light or no wind or rain). The survey period should be extended to 12 nights when rain or wind are forecast. Because PAM is less labour intensive than active surveys (i.e., spotlighting and call playbacks with multiple observers and several nights’ survey per site), its use will facilitate broad-scale surveys for Yellow-bellied Gliders.
Rendall, AR. Webb, V. Sutherland, DS. White, JG. Renwick, L. Cooke, R.
Understanding when and where roadkill is most likely to occur is vital to reducing wildlife-vehicle collisions. However, little is known about how roadkill rates change through time and whether or not the key influences on roadkill also change. Understanding changes in roadkill will facilitate the best implementation of mitigation measures. We aimed to determine how roadkill rates have changed between two distinct time periods and assess whether the spatial and temporal drivers of roadkill rates may have changed: with a view to informing species-specific mitigation strategies.
Managing ecosystems in the face of complex species interactions, and the associated uncertainty, presents a considerable ecological challenge. Altering those interactions via actions such as invasive species management or conservation translocations can result in unintended consequences, supporting the need to be able to make more informed decisions in the face of this uncertainty.
Rendall, AR., White, JG., Cooke, R., Whisson, DA., Schneider, T., Beilharz, L., Poelsma, E., Ryeland, J., Weston, MA.
Autonomously triggered cameras are a common wildlife survey technique. The use of attractants and surrounding microhabitats are likely to influence detection probabilities and survey outcomes, however, few studies consider these factors. We compared three attractants (peanut butter-based, tuna-based, and a control) in a Latin square design through a coastal shrubland with high microhabitat variability at Cape Otway, Victoria, Australia. Deployments involved 36 cameras for four days in each of five years. The percentage cover of each vegetation structural type (low [no or sparse cover], moderate [grass] or high [shrubs]) within 20 m of each camera was calculated and reduced to a single variable using PCA. Dynamic occupancy modelling, with lure type and vegetation structure as covariates of detection probability, found that peanut butter attracted the greatest diversity of species (24 of 35 species, 69%) and yielded the greatest number of detections (50% of 319) when compared to tuna oil (66% and 24% respectively) and the control (43% and 26% respectively). Peanut butter attracted more Macropodidae (wallabies) and Muridae (rats and mice); however, vegetation structural variables were the greatest influence on Corvidae/Artamidae (raven/currawong) detections with higher detectability in more open areas. Vegetation structure also influenced Muridae detections. This study reinforces the critical choice of appropriate attractants and camera placement when investigating vertebrate groups and highlights the role of microhabitat in the detection of small mammals and birds. We suggest future large-scale camera surveys consider different bait types and microhabitats in their designs, to control for any biases and enable future advice on ‘optimal’ methods.
Charuvi, A., Lees, D., Glover, HK., Rendall, AR., Dann, P. and Weston, MA.
For a given species, why does one bird fly when another doesn’t?
This process is often referred to as habituation – where some individuals become accustomed to repeated stimuli and therefore respond less. Habituation has been extensively discussed in relation to its importance in informing guidelines for mitigating the impacts of human disturbance on wildlife. However, most studies only consider behavioural responses of individuals, not the underlying physiological responses (Weston et al. 2012). Only a limited number of studies have considered the behavioural and physiological response of individuals to threatening stimuli. These studies are important as it may be that birds respond physiologically prior to showing any behavioural response, meaning our measures of the impact of negative stimuli (i.e. human usage of an ecosystem) may under-estimate true impacts. Therefore, in this study we investigated whether physiological costs were incurred prior to, or simultaneously with a behavioural response.
We investigated the spatial and temporal activity of long-nosed potoroos (Potorous tridactylus tridactylus) and feral cats (Felis catus) on French Island, Victoria. This population of potoroo’s has co-existed with cats since their introduction to the island, and we sought to understand the mechanisms by which this population was able to continue to persist.
Zonation is a dominant feature of coastal ecologies, yet comparatively few studies are available on zonation of ecological assemblages in coastal dunes. No study is available which examines zonation of small terrestrial mammals in dunes. We use a dataset of 10 years of mammal trapping near Cape Conran, eastern Victoria, Australia and show that small mammals were common in this dune system. The only introduced small mammal was detected in a narrow band above the beach/dune interface, while native small mammal assemblages dominated in the rest of the dune field. This clear zonation may result from habitat preference, competition, predation and species-specific predator risk tolerances, marine or beach subsidies or a combination of these influences.