In 2013, we began monitoring feral cats using a network of trail-based camera traps at the western edge of Oxley Wild Rivers National Park. Over time we have supplemented this near-continuous, passive monitoring with occasional GPS-collaring, to improve our understanding of this priority pest species (per NSW Biosecurity Act 2015) where a significant conservation area abuts productive agricultural lands.
In this talk, we present insights into local feral cat population dynamics, highlighting aspects of their temporal and spatial ecology observed over more than a decade. In particular, we also present comparisons of the cat population before and after the 2019-20 megafires, which severely impacted local vegetation and sympatric fauna.

Effective monitoring underpins useful wildlife management programs, yet the influence of camera trap spatial arrangement on population density estimates—and the capacity of different designs to reliably detect population changes—remains underexplored. Feral cats are a major conservation threat in Australia, where robust monitoring is critical for assessing management outcomes. However, few studies have empirically assessed the power of different camera trap configurations to assess feral cat population densities. Here, we aim to improve feral cat monitoring by evaluating camera trap methodologies and analytical approaches for the estimation of population densities. Further, we evaluate the utility of the different survey methods to detect changes in a feral cat population. We deployed four camera arrays – 250 m grid, 500 m grid, 1000 m grid, and 1000 m spaced on-road transect – to monitor a feral cat population over a ten-week period. We generated density estimates for each array to determine how camera spatial arrangement affected population density estimates. We simulated population declines to assess the ability of the different arrays to detect population reductions ranging from 10-60%. The 500 m grid array had density estimates closest to the density estimated by the full dataset, while 250 m grid and road-based cameras were more likely to estimate higher densities. However, confidence intervals from all arrays had considerable overlap. Simulations indicated road-based cameras, followed by 500 m grid cameras, were best able to detect changes in feral cat populations. Road-based linear arrays are simple to install and maintain, while grid-based arrays require more time, effort and resources to deploy well. For greater accuracy in density estimates a 500 m spaced camera grid array may be required to monitor feral cat populations. However, in this study area, feral cat density and changes to population density can be adequately monitored using a road-based linear camera array.

In invasion biology, understanding niche overlap between native and invaded ranges is crucial for predicting and managing the spread of invasive species. Consequently, we compared the environmental envelopes (i.e., components of temperature and precipitation regimes) of emerging weed species (N =80) of Queensland in their native habitats to those in their new, invaded areas in Australia and vice-versa using ecological niche model, species equivalency and niche similarity tests. These tests help to ascertain if an invasive species has retained its original ecological preferences (niche conservatism) or has adapted to new environmental conditions (niche shift) in the invaded range. Tests of niche equivalency (as indicated by Schoener’s D) vary across species (0.035- 0.430; mean 0.208) and were significant for all species (P < 0.05), suggesting limited degree of overlap of niches between invaded and native ranges. However, for a sizeable number of the species (21/80=26.3%), using the reciprocal niche similarity tests, apparent niche shifts seem to prevail, suggesting there is a need to expand surveillance to include a broader range of habitats, as the species may adapt to new environmental conditions. Very few weed species examined (10/80=13%) expressed joint/reciprocal significant differences in their similarity tests when their native environmental envelopes were projected on their invaded ranges in Queensland/Australia and vice versa when invaded range data were projected on native environment (i.e. niche stability/conservatism). Thus for these few species management will need to focus more on monitoring and control efforts on areas with environmental conditions like that in their species' native ranges. The remaining species (41/80=51%) showed asymmetric similarity test results, indicating patterns of niche expansion (increased use of fundamental niche in invaded range) or possible use underutilized niche. It is concluded that incorporating niche similarity analyses into risk assessments can enhance the prediction of invasion fronts and inform targeted management interventions.

Wildflower meadows in Melbourne urban parklands often use soil capping techniques to suppress weed germination. While capping is an effective solution, it comes with its fair share of problems.
Capping substrates are highly sort after for construction, limiting their availability for restoration efforts. Furthermore, many substrates are unviable for urban capping, leading projects to look for alternative substrates. Recycled substrates created from leftover construction materials provide a readily available and inexpensive solution. These substrates are relatively new however, and research on their effectiveness at suppressing weeds is lacking. Investigating and proving the effectiveness of recycled substrates as a capping material will potentially create a cheaper alternative for restoration efforts, and aid in successfully re-establishing urban native meadows.
To study the effectiveness of recycled substrates, we conducted capping trials on 9 common urban weed species using 5 different substrates (3 recycled 2 control). Weed seeds were placed under 3 capping depths (2cm, 4cm, 6cm) and each depth was replicated 7 times for each species and substrate. Samples were left to germinate over the course of 6 weeks, with weed germination and emergence recorded over the period.
We hypothesized that 1) Species depth of emergence would be effected by seed size, 2) Denser substrates would be more effective at suppressing weeds, and 3) Recycled substrates would suppress the emergence of urban parkland weeds.

Invasive deer in Australia have been associated with threats to native vegetation structure and composition, water quality, and economic impacts on agriculture. As their numbers continue to grow and their range increases, management becomes increasingly necessary, which requires a robust system of monitoring across all parts of their range. My project aims to compare survey methods and investigate patterns of site occupancy of invasive deer, particularly sambar deer (Rusa unicolor) in Namadgi National Park. The park’s rugged subalpine terrain and dense post-fire vegetation make monitoring difficult, and while the impacts and density of feral deer have been studied in targeted areas of Namadgi, this is the first study to examine landscape-scale occupancy of feral deer across the park. By comparing monitoring methods (camera trapping with scat and sign searches) across different vegetation types in the park, this study aims to improve understanding of deer occurrence patterns within Namadgi NP, and inform future monitoring protocols. In summer and autumn surveys, deer were detected at 5 sites via scat surveys, and 19 sites via camera surveys, with sambar deer the most common, followed by fallow deer and red deer. Overall detection frequency, and detection of sambar deer did not differ among grassy woodland, dry sclerophyll forest and wet sclerophyll forest sites, while fallow deer tended to be more commonly detected on grassy woodland sites. Further analysis will incorporate autumn-winter survey data and explore deer occurrence patterns in relation to landscape factors such distance to water and roads. Understanding detection and occurrence of a low-density deer population will assist with ongoing management in the NP and is essential for preventing further deer expansion.

Ecological factors influence the evolution and adaptation of morphological traits by shaping functional performance within specific habitats. Invasive species, when introduced to novel environments, encounter new selective pressures that can drive phenotypic change as they adapt to establish successfully. While the effects of environmental variables on the phenotype are relatively well-studied, few investigations have addressed whether these environmental influences act similarly on populations in both native and introduced ranges. The European rabbit (Oryctolagus cuniculus) serves as a model organism for exploring this question. Originally native to the Iberian Peninsula, this species has been introduced to a variety of environments worldwide. One of the most widespread and successful introductions occurred in Australia, where rabbits have become well-established. This broad geographic distribution across contrasting habitats makes the European rabbit an ideal system for examining whether environmental drivers of phenotype operate similarly in native and invasive populations. In this study, we examined the effects of environmental variables—specifically temperature, precipitation, and aridity—on functionally-relevant morphological traits including cranium size and shape, tooth row length, snout volume, and bulla volume in both European and Australian populations of European rabbits. Our results indicate that environmental conditions do influence morphology; however, the nature and magnitude of these effects differ between native and invasive populations. These findings underscore that environmental drivers of phenotypic variation may act in population-specific ways, even within a single species.

Invasive non-native plant pathogens such as myrtle rust pose a significant threat to Australian plant species and forests. The extent to which land clearing alters the density and distribution of susceptible species in the Myrtaceae family is crucial to understanding how myrtle rust affects forest landscapes. We hypothesized that patches of wet sclerophyll forest with greater human disturbance—particularly land clearing—would show higher densities of susceptible species in the understory layer. This is likely due to the ability of some highly susceptible species to act as early colonisers and their capacity to coppice, enabling rapid recovery after disturbance.
To test this, we surveyed 21 patches of wet sclerophyll forest in eastern Australia (Queensland Regional Ecosystem 12.11.2), varying in land tenure and historical clearing. We found a positive interaction between past land clearing and myrtle rust impacts, largely driven by the abundance of rose myrtle (Archirhodomyrtus beckleri), a highly susceptible species. Sites with more of these trees also showed more severe disease impacts.
Our findings show that regrowth patches are more vulnerable to myrtle rust because of the higher prevalence of early colonising myrtle species in their understory and this result has management implications. Formerly heavily cleared sites may benefit from increased restoration efforts like the removal of woody debris (i.e. dense understories of dead myrtle species) and weeding, while less disturbed areas should receive targeted conservation to protect healthier endangered species.

Background
Feral animals such as feral pigs, cats, deer and European red fox, as a collective, they can contribute carry and transmit many pathogens, prions and other microorganisms; and impact food and water security, biodiversity loss, are an antimicrobial resistance risk; and contribute to climate change by damaging carbon sinks. To address these One Health issues requires multisectoral collaboration, communication, coordination and capacity building.
Objectives
Wildlife Health Australia conducted a purposive sample survey with state/territory governments, Indigenous land management groups, not-for-profit organisations, land managers, invasive species researchers; and industry to improve understanding of the general state of terrestrial feral animal disease surveillance and management in Australia; and to gauge whether feral animal disease and management aligns with the severity of threat they pose to human health, native wildlife, environment and agriculture.
Results
Forty-three responses were received. Results showed that respondents recognised that feral animals carry pathogens and can transmit diseases, however this is not the major driver for management; and that there appears to be little overlap between those involved in feral animal disease surveillance and those involved in management. The survey results indicate there is considerable interest and support (72% of respondents) for developing a national feral animal disease surveillance and management network.
Conclusion
Feral animal disease surveillance and management with One Health approach is yet to gain real traction in terms of a nationally coordinated activity. The survey results suggest there the need for a more strategic, tailored and systematic approach to address the issue of feral animal diseases in Australia.

Biological invasions are the most prevalent threat to Australian biodiversity and ecosystem function (Ward et al. 2021). The Enemy Release Hypothesis (ERH) posits that introduced species benefit from escaping coevolved enemies, which can contribute to invasion success, whereas the Missed Mutualist Hypothesis (MMH) proposes that losing coevolved mutualists can hinder invasion success. To become invasive, the benefits of enemy release must outweigh the costs of missing mutualists. We tested both hypotheses using Senna obtusifolia, a highly invasive tropical weed with extrafloral nectaries that attract ants that can deter herbivores and seed predators. We manipulated ant access and nectar production at multiple field sites in Mexico (native range) and Australia (invaded range). We also manipulated pollen deposition and observed floral visitors and pollinators in both regions. We assessed antagonistic (herbivores and seed predators) and mutualistic (ants and pollinators) interactions in both regions and whether their diversity and plant impacts differed, as predicted by ERH and MMH. Evidence for the ERH was mixed. Contrary to our expectations based on the ERH, chewing and mining herbivore species were 120% more diverse in the invaded range. However, pre-dispersal seed predation, which reduces reproductive output, was higher in the native range, supporting the ERH. We found no significant difference in pollinator diversity between regions and seed set from natural pollination was greater in the invaded region compared to the native region, providing no support for the MMH. Overall, our findings suggest that reduced impact from enemies, coupled with no fitness reduction associated with the removal from coevolved mutualists may contribute to the success of alien invaders.

Ward, M., Carwardine, J., Yong, C. J., et al. (2021). Ecology and Evolution, 11, 11749–11761. https://doi.org/10.1002/ece3.7920