Department of Biodiversity, Conservation and Attractions

Reef fish assemblages are dynamic and heterogeneous across both temporal and spatial scales. Understanding these patterns is essential for effective management strategies that aim to protect marine communities. We investigated whether previously described cross and longshore patterns in reef fish assemblages persisted after a decade of high ocean temperature variability driven by the El Niño-Southern oscillation and a significant marine heatwave in 2011. Two nearshore marine parks near Perth, Western Australia, located 70 km apart, were sampled in 2012 and 2023 using Baited Remote Underwater stereo-Video systems. At each location, distinct inshore, midshore, and offshore reef lines were targeted across a depth gradient of 3-23 m. Inshore-to-offshore assemblage patterns described in 2012 remained temporally consistent in 2023, with each reef line representing distinct compositions at both locations. The mean relative number of species, the mean relative abundance of fish per deployment, and the mean relative abundances of most individual feeding guilds, were also similar between years. Although assemblage and feeding guild compositions differed at a few locations between years, these changes were likely driven by the localised variation in the distribution of some focal species across reef lines. Planktivores were the only feeding guild to significantly increase in abundance over time. As cumulative anthropogenic and climate pressures increase, it is likely assemblage modification will occur more often. To protect the full range of fish assemblages, it would be appropriate for future spatial management to include fully protected sanctuary zones across inshore, midshore, and offshore reef lines at both locations. • Cross-shore assemblage patterns of increasing species richness and fish abundance was consistent in 2012 and 2023 • Reef fish assemblage compositions had minor differences between 2012 and 2023 • Planktivores were the only feeding guild to increase in abundance • For future management, including no-take sanctuary zones across all three reef lines would be most appropriate

Soil microbiomes are fundamental ecosystem components that are increasingly used to monitor the efficacy of restoration efforts. However, given high levels of functional redundancy among soil microbial taxa and the subsequent lack of definitive taxa-function links, taxonomic assessments (e.g., via metabarcoding) alone are limited for inferring ecological recovery. Here, we used shotgun metagenomics on soils from six post-agricultural restoration sites in southwest Western Australia to test whether soil microbial functional potential recovers following restoration plantings. We compared taxonomic and functional gene diversity and composition across degraded, passively regenerated, revegetated, and remnant land conditions. Effective number of functions (alpha diversity) did not differ across land conditions. However, functional composition (beta diversity) differed between remnant and revegetated conditions and associated with altered soil abiotic properties, especially elevated phosphorus. Remnant soils supported a greater diversity of phosphorus metabolism functions despite lower available phosphorus, indicating a microbial adaptation to nutrient limitation in phosphorus deficient soils. Rather than indicating a lack of functional recovery, these results suggest a functional response to persistent agricultural legacies that may reflect a shift toward an alternative state. Restoration interventions that aim to target the soil microbiome (e.g., soil inoculations) or directly address abiotic legacies (e.g., phosphorus mining plants) may therefore be required to facilitate recovery of the soil microbial functions and the wider ecosystem.

Context Extreme heat events are intensifying under climate change, yet their sublethal effects on threatened mammals remain poorly understood. Aims We investigated behavioural responses of the critically endangered western ringtail possum (Pseudocheirus occidentalis; ngwayir) to extreme heat on the Southern Swan Coastal Plain of Western Australia. Methods Using tri-axial accelerometer collars, we quantified diel activity patterns of 10 ngwayirs across two peppermint (Agonis flexuosa) woodland populations during summer of 2024–25, encompassing several heatwaves. Generalised additive models were used to examine how activity varied with time of day, sex, and daily maximum temperature. Key results Activity was strongly structured by temperature and diel period. On very hot days (>40°C), nocturnal activity declined by up to 43% in males and 31% in females compared with cooler days (27°C), with the largest reductions during early-evening peaks. Activity increased later at night as temperatures declined, indicating temporal shifts in foraging effort. These results demonstrate pronounced behavioural sensitivity to thermal conditions below lethal thresholds. Conclusions Ngwayirs reduce nocturnal activity during extreme heat, consistent with short-term behavioural thermoregulation. Implications Sublethal heat exposure significantly alters daily activity patterns in this critically endangered marsupial. Such behavioural suppression likely carries energetic costs that could reduce fitness and reproductive output. Integrating behavioural responses into climate-vulnerability assessments is essential for predicting species persistence under increasing heatwave frequency.

Context Since European settlement, the northern quoll (Dasyurus hallucatus) or wiminyji, a marsupial predator native to northern Australia, has experienced significant declines across much of its range due to invasive predators, habitat destruction, altered fire regimes, and the introduction of cane toads (Rhinella marina). While declines are well documented in most populations, there is limited Western scientific evidence to suggest that similar declines have occurred within the Pilbara population – the most arid section of the species’ range. Aims Here, we aim to document accounts relating to wiminyji, including its historical distribution, habitat use, and threats, from Martu Elders, the Traditional Owners of the western desert region in Western Australia and the easternmost extent of the species’ Pilbara range. Methods On-country ninti, or knowledge sessions, with Martu Elders were conducted following culturally appropriate protocols in Karlamilyi National Park, near the site where a small population of wiminyji was first detected by Western science in 2012. Testimonies regarding the distribution and ecology of wiminyji were recorded and are presented here in the context of existing knowledge from a Western scientific perspective. Key results Martu Elders recalled wiminyji as historically widespread across both sandy and rocky habitats, including areas now well outside their known contemporary range. Their accounts suggest that significant declines occurred within the span of two to three generations, attributed to the impacts of feral predators and altered fire regimes. Conclusions This study demonstrates that Martu knowledge provides a critical historical baseline for wiminyji, revealing extensive declines in arid Australia that were previously undocumented by Western science. Implications Accounts from Martu Elders fill an important gap in the Western understanding of the wiminyji’s historical distribution, providing a more accurate baseline against which the species’ current status can be assessed. In addition, they offer valuable ecological insights that align with trends identified in recent research.

Widespread climate-driven increases in background tree mortality rates have the potential to reduce the carbon storage of terrestrial ecosystems, challenging their effectiveness as natural buffers against atmospheric CO2 enrichment with major consequences for the global carbon budget. However, the global extent of trends in tree mortality and their drivers remains poorly quantified. The Australian continent experiences one of the most variable climates on Earth and is host to a diverse range of forest biomes that have evolved high resistance to disturbance, providing a valuable test case for the pervasiveness of tree mortality trends. Here we compile an 83-year tree dynamics database (1941-2023) from >2,700 forest plots across Australia covering tropical savanna and rainforest and warm and cool temperate forests, to explore spatiotemporal patterns of tree mortality and the associated drivers. Over the past eight decades, we found a consistent trend of increasing tree mortality across the four forest biomes. This temporal trend persisted after accounting for stand structure and was exacerbated in forests with low moisture index or a high competition index. Species with traits associated with high growth rate-low wood density, high specific leaf area and short maximum height-exhibited higher average mortality, but the rate of mortality increase was comparable across different functional groups. Increasing mortality was not associated with increasing growth, given that stand basal area increments either declined or remained unchanged over time, but it was associated with increasing temperature over time. Our findings suggest that ongoing climate change has driven pervasive shifts in forest dynamics beyond natural recovery in a range of forest biomes with high resilience to disturbance, threatening the enduring capacity of forests to sequester carbon under current and future climate scenarios.

Abstract Large‐scale assessments of plant condition are needed in restored plant communities to evaluate if ecosystems are functioning similarly to natural reference systems. Remote sensing can yield information on plant condition in a more efficient way than current on‐ground physiological methods, which often require destructive sampling and are difficult to perform at large scales. In this study, we explore the use of near‐surface remote sensing approaches—leaf‐level thermography and hyperspectral reflectance—to estimate key physiological parameters and track seasonal change in a diverse group of plant species growing in a restored mine site of Western Australia. In this system, deviations from expected plant condition are mainly driven by water availability, which translates in various degrees of drought stress. We investigated the relationships between traditionally measured physiological variables and remotely sensed proxy indicators, with the following goals: (1) to assess the extent to which remotely sensed proxy indicators can reliably estimate key physiological variables in functionally diverse plant species, and (2) to explore a multivariate approach to track seasonal change in different species using a combination of remotely sensed proxy indicators. Our results indicate that univariate relationships between physiological variables and their remotely sensed proxy indicator for leaf water content and total chlorophyll concentration were accurately predicted for all species at the leaf level. This was not the case for fluorescence and stomatal conductance. Through multivariate analysis, we found that, when grouping samples through seasonal data centroids, three different data sets (physiological variables, all remotely sensed proxy indicators and remotely sensed proxy indicators from hyperspectral reflectance only) outlined very similar transitions across seasons in four out of the five studied species. This indicates that, when combined, remotely‐sensed proxy indicators generated through leaf hyperspectral reflectance have the potential to detect deviations in plant condition in a wide range of plant functional types. Using this approach to detect changes in levels of plant stress could enable early detection of potential issues in restoration and therefore may be used to inform adaptive management to improve long‐term restoration strategy and outcomes. Practical implication : through the multivariate approach based on remotely sensed proxy indicators that we present here, plant condition assessments can be conducted more efficiently in the context of ecological restoration.

Context Conservation managers often have little information on distribution ranges and ecological characteristics of rare species, thereby hindering effective decision-making. This challenge is evident for arboreal mammals of northern Australia where species vary widely in abundance, are nocturnal and cryptic, and exhibit regionally divergent patterns of rarity and decline. Aims We compare (1) trapping niche, (2) denning and foraging niche and (3) vegetation habitat preferences to test for links between niche and rarity among arboreal species. Methods Survey data obtained using a variety of terrestrial and arboreal methods are used to define trapping niche, vegetation habitat preferences and abundance/distribution of arboreal mammal species in Western Australia’s northern Kimberley. Denning and foraging niche is defined based on available literature. Key results Based on combined niche observations, we suggest that arboreal denning species with a preference for open forest vegetation are the most prone to rarity, restricted distributions and decline in the Kimberley. Very restricted extent of suitable open forest vegetation in the Kimberley may locally exacerbate threats to forest specialists. Generalist, terrestrial denning species preferring savanna woodlands/shrublands and rugged rocky habitats were more abundant and less restricted in their distributions than forest specialists. Conclusions These results highlight the local importance of small areas of open forest for threatened arboreal mammals in the Kimberley. Implications We suggest that targeted adaptive management interventions to preserve and enhance open forest vegetation and arboreal habitat including den hollows, through application of low intensity prescribed burning for protection from damaging wildfires, would benefit specialist arboreal species.

Abstract Ecological monitoring plays a crucial role in conserving biodiversity. However, ensuring that monitoring programs possess adequate statistical power—the capacity to detect changes in populations with a high level of confidence—remains a significant challenge for wildlife managers worldwide. The rise in popularity of camera traps has led to a proliferation of models with varying costs, specifications, and capabilities. This diversity presents both opportunities and challenges for wildlife managers, as selecting the most suitable model requires careful consideration of detection probabilities, deployment durations, and overall cost‐effectiveness. Here, we present a case study comparing the performance of two commercially available camera trap models widely used for monitoring eight species groups within a global biodiversity hotspot. While Reconyx cameras demonstrated superior detectability for most species, the lower‐cost Swift models proved more cost‐effective for increasing statistical power in large‐scale monitoring programs. These results highlight the importance of comparing monitoring technologies using metrics that go beyond nightly detectability, such as statistical power, and evaluating these technologies at the scale at which they are intended to be implemented. These findings provide a framework for wildlife managers to optimize monitoring programs while balancing cost and performance.

In many plants, pollinators are attracted to the flowers by scent. Among plants, Banksia (Proteaceae) is exceptional in being pollinated by several functional groups of vertebrates, including honeyeater birds, members of two marsupial orders, and rodents. Here, we test the hypothesis that in Banksia interspecific variation in the frequency of floral visitation by functionally different vertebrate pollinators can be explained by floral scent traits. We used GC-MS to analyse floral volatiles of nine co-occurring Banksia species and tested for correlations between floral visitation by vertebrate pollinators quantified through camera trapping and (i) the abundance in floral headspace of three candidate mammal-attracting compounds, and (ii) overall scent richness (number of volatiles detected). Visitation by non-flying mammals, but not birds, was positively correlated with scent richness, aligning with general trends for other functional groups of pollinators that use olfaction when foraging for nectar. Visitation by native and introduced mice, but not by Honey possums, was correlated with median abundance of 3-methyl-1-nitrobutane and 2-methyl-1-nitrobutane - structural isomers of 1-nitropentane, a known semiochemical in Black rat that is attractive to both sexes. Further, the known rodent semiochemicals, sulcatone (6-methyl-5-hepten-2-one) and 2-methylbutanoic acid were detected in species frequently visited by mice. Our results demonstrate that within mixed-vertebrate pollination systems, the frequency of visitation by functionally different vertebrate pollinators can be partially explained by interspecific variation in floral scent chemistry. While behavioural tests are needed to confirm attractiveness of specific compounds, our results provide the first evidence for chemical adaptation to pollination by rodents in Australian flora.