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Addressing threats to biodiversity from pest species is a global challenge. One such challenge is to mitigate the impact of an overabundant Australian songbird, the noisy miner Manorina melanocephala, on woodland birds. The overabundance of noisy miners is listed as a key threatening process under federal biodiversity legislation, but current understanding of where and how noisy miner populations can be managed to yield conservation benefits is unclear. We evaluated the effectiveness of noisy miner removal across 12 treatment areas totaling 3913 ha and nine control areas totaling 1487 ha important for the critically endangered regent honeyeater Anthochaera phrygia. Removal of noisy miners significantly reduced their densities in all but one of the treatment areas. In 10 of the 12 treatment areas, noisy miner densities remained below an impact threshold of 0.65–0.83 birds ha−1 for at least 3 to more than 12 months. The percentage of suitable noisy miner habitat in the surrounding landscape was not a strong predictor of noisy miner management success. Regent honeyeaters occupied six treatment areas, nesting successfully in four. The abundance of other songbirds increased post‐miner removal in seven areas, decreased in three, and was mixed in two. Data from the control areas showed some variation in songbird numbers was independent of noisy miner management. We conclude that noisy miners can be managed in areas of high conservation value for a minimum cost of AUD $10 ha−1. Larger treatment areas may be more important than the broader landscape context in maintaining long‐term noisy miner suppression. Standardized, long‐term monitoring is crucial to identify not only the drivers of pest species recolonization but also locations where threats from pests on endangered species can be addressed effectively while minimizing animal welfare and financial costs. [ABSTRACT FROM AUTHOR]

Proponents of development projects (e.g., new roads, mines, dams) are frequently required to assess and manage their impacts on threatened biodiversity. Here, we propose that the environmental legislation and standards that mandate such assessments are failing those threatened species and ecological communities listed as vulnerable. Using a case study of Australia's key environmental legislation, we highlight that vulnerable ecological communities receive no statutory protection, while vulnerable species are held to a less stringent standard in the impact assessment process compared with those that are endangered or critically endangered. In the 19 years since Australia's Environment Protection and Biodiversity Conservation Act 1999 was enacted, four times as many vulnerable species have declined in their threat status than have improved. Beyond Australia, we demonstrate the global relevance of this issue, as it applies to internationally recognized best practice impact assessment guidelines. These cases provide a cautionary tale: without greater attention and stricter assessment criteria in the impact assessment process, the vulnerable species of today risk becoming the endangered species of tomorrow, with all the attendant costs and missed opportunities for recovery that this implies. [ABSTRACT FROM AUTHOR]

Globally, insectivorous birds are at high risk of decline. One explanation of this relates to changes in invertebrate resources due to anthropogenic pressures. The northern population of the eastern bristlebird (Dasyornis brachypterus) relies heavily on invertebrate food resources, and has experienced an 80% population reduction over the past 40 years. We investigated invertebrate abundance and nutritional quality across 23 currently and historically occupied northern bristlebird sites to determine whether extant territories were associated with more, or more nutritious, invertebrate resources. Pitfall and leaf‐litter invertebrate sampling were done in both breeding and non‐breeding seasons from 2014 to 2016. There was no difference in abundance, biomass or nutritional value of invertebrates between occupied and abandoned territories; however, within territories invertebrate abundance and nutritional value did correspond to the habitat characteristics with which bristlebirds are associated. Nutritional value of invertebrates increased with proximity to rainforest, while the abundance of macro‐invertebrates (>1 mm) was correlated with grass height. Bristlebird territories are often close to rainforest margins, and these ecotones may provide more nutritious mesic‐associated invertebrates. Higher abundances of large invertebrates in tall grasses may also contribute to the known association of bristlebirds with tall grasses. Maintenance of tall grass adjacent to rainforest through appropriate fire and grazing management is likely to be important for northern bristlebird recovery and long‐term persistence of the population. [ABSTRACT FROM AUTHOR]

Reintroductions are a critical tool for threatened species’ conservation, and their success will depend on correctly identifying the key habitat requirements needed for persistence. The Critically Endangered, isolated northern population of the Eastern Bristlebird has declined to an estimated 40 individuals. A successful captive breeding programme means that future reintroductions are likely; however, knowledge of fine-scale habitat requirements associated with persistence is limited. To inform reintroduction efforts we compared habitat attributes of currently occupied and historically occupied habitat patches. Persistence was highly dependent on the extent of contiguous grassy habitat, with larger patches more likely to contain bristlebirds. This association was contingent on grass structure, with less chance of bristlebirds occurring at large sites lacking a tall, thick grassy understorey. Topographic and environmental heterogeneity within large habitat patches likely allows unburnt habitat to persist following fire, increases the temporal availability of prey and allows persistence of a population. For a largely ground-dwelling species, the presence of tall, thick grasses is expected to provide important shelter for foraging and nesting activities. Use of appropriate fire to maintain large contiguous patches with a thick, tall grassy ground layer will be critical for the continued persistence and successful reintroduction of the northern Eastern Bristlebird. [ABSTRACT FROM AUTHOR]

Land clearing threatens biodiversity, impairs the functioning of terrestrial, freshwater, and marine ecosystems, and is a key contributor to human-induced climate change. The rates of land clearing in the State of Queensland, Australia, are at globally significant levels, and have been the subject of intense and polarised political debate. In 2016, a legislative bill that aimed to restore stronger controls over land clearing failed to pass in the Queensland Parliament, despite the clear scientific basis for policy reform. Here, we provide a short history of the recent policy debate over land clearing in Queensland, in the context of its global and national ecological significance. Land clearing affects regional climates, leading to hotter, drier climates that will impact on the Queensland economy and local communities. Loss of habitat from land clearing is a key threatening process for many endangered animals and plants. Runoff from land clearing results in sediment and nutrient enrichment, which threatens the health of the Great Barrier Reef. Australia has made national and international commitments to conserve biodiversity and reduce our greenhouse gas emissions, but current land clearing policies are not consistent with these commitments. Stronger regulation is needed to reduce vegetation loss, such as target-based regulation, which sets a cap on land clearing and could effectively halt vegetation loss over the long term. Lasting policy reform is required, and we recommend an effective policy mix that restricts clearing, provides economic opportunities for vegetation retention, and informs the Australian community about the value of native vegetation. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Thresholds often exist in the relationship between species richness and the area of remaining habitat in human-modified landscapes, prompting debate about the mechanisms responsible. We hypothesize that if species-area relationships differ with underlying factors such as landscape productivity, and such factors correlate with patterns of habitat clearance, then spurious thresholds can arise where the separate species-area relationships intersect. We assessed whether this phenomenon could explain landscape-level species-area relationships for birds occupying 31 landscapes of 100 km2 in eastern Australia. Location Eastern Australia. Methods Landscape-level species richness estimates were modelled as a function of the percentage of native vegetation remaining in the study landscapes. The performance of traditional species-area curves and continuous and discontinuous piecewise models was compared using an information theoretic approach. Separate models for high- and low-productivity and high- and low-fragmentation landscapes were examined to determine whether they implied different species-area relationships. Results The species-area relationship exhibited a rapid change-point at approximately 40% vegetation cover, but this was most parsimoniously explained by two disjunct slopes rather than a continuous threshold model or a classic species-area curve. Exploration of models fitted separately to high- and low-productivity landscapes suggested that such landscapes may differ in their characteristic species-area relationships. Main conclusions The observed pattern is consistent with the spurious threshold hypothesis, and opens a new avenue of enquiry into the processes behind apparent ecological thresholds. This hypothesis may be valid in other regions where clearing history is confounded by underlying factors such as landscape productivity, and demands further research. In such systems, real thresholds for different landscape types may occur at different levels of cover, or might not exist at all. If so, a simple space-for-time substitution may not be valid, and management prescriptions based on threshold values (e.g. 40%) will be flawed. [ABSTRACT FROM AUTHOR]

Many nations are struggling to reduce deforestation, despite having extensive environmental protection laws in place and commitments to international agreements that address the biodiversity and climate crises. We developed a novel framework to quantify the extent to which contemporary deforestation is being captured under national and subnational laws. We then applied this framework to northern Australia as a case study, a development and deforestation hotspot with ecosystems of global significance. First, deforestation may be compliant under all relevant legislation, either through assessment and approval or because of exemptions in the legislation. Second, deforestation may be compliant under at least one relevant law, but not all. Third, there may be no evidence of deforestation assessment or exemption from assessment, despite their apparent requirement, which could mean the deforestation is potentially noncompliant. Finally, deforestation may occur in an area or under circumstances that are beyond the intended scope of any relevant legislation. All deforestation that we analyzed was hypothetically covered by one or more laws. However, 65% of deforestation was potentially noncompliant with at least one law. Because multiple laws could be relevant to a given clearing event, the majority of clearing was still compliant with at least one law, but of these events, only a small proportion was explicitly approved (19%). The remaining were permitted under various exemptions. Of all the legislation we analyzed, most of the exempt clearing occurred under one subnational law and most potentially noncompliant clearing occurred under one national law. Our results showed that even a nation with a suite of mature environmental protection laws is falling well short of achieving international commitments regarding deforestation. Our framework can be used to pinpoint the pathways of policy change required for nations to align local laws with these international accords. [ABSTRACT FROM AUTHOR]