School of Agriculture, Food and Ecosystem Sciences - Research Publications
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ItemIntegrating species metrics into biodiversity offsetting calculations to improve long-term persistence(WILEY, 2022-04)Abstract Several methods of measuring biodiversity in development‐offset trades exist. However, there is little consensus on which biodiversity metrics should be used for quantifying development impacts and assigning offsets. We simulated development impacts in a virtual landscape and offset these impacts using six biodiversity metrics: vegetation area, vegetation condition, habitat suitability, species abundance, metapopulation connectivity and rarity‐weighted richness. We tested long‐term impacts of metric choice during offsetting by combining simulated landscapes with population viability analyses. No net loss or net gains in habitat were achieved using all metrics except vegetation area and condition. Limited habitat and like‐for‐like requirements resulted in offsets exhausting available habitat in each vegetation class before offset requirements were met when using vegetation‐based metrics. We also found that impact avoidance was an important driver in how much compensation offsets could deliver. When impacts avoided high‐suitability habitats, all six metrics achieved no net loss or net gains for most species. However, when core habitats were developed, none of the metrics were able to consistently prevent population declines. Synthesis and application. When impacts on high‐quality habitat were avoided, and assuming the protection and restoration benefits can occur in practice, vegetation‐based metrics may produce offsets which deliver gains in species abundance equivalent to species‐specific metrics. However, species‐specific metrics outperformed vegetation‐based metrics when core habitats were lost. Applying avoidance measures as a first step to minimise biodiversity impacts during development will significantly improve offset outcomes for species and result in greater long‐term population benefits delivered through offsetting.
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ItemRemotely sensed vegetation productivity predicts breeding activity and drought refuges for a threatened bird in semi-arid Australia(WILEY, 2022-08)Abstract Refuges play a critical role protecting species against the effects of climate change. Managing high priority refuges could improve species resilience and facilitate dispersal during periods of environmental change. In this study, we identified drought refuges in semi‐arid Australia for a threatened bird, the malleefowl Leipoa ocellata. Using a Poisson regression model, we quantified the effect of remotely sensed vegetation indices, rainfall, soil moisture and site characteristics on malleefowl breeding activity at 144 sites surveyed from 2000 to 2017 during and after drought. We tested the effect of two vegetation productivity indices on malleefowl breeding activity – the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) – averaged across three temporal and three spatial scales during the mound building and incubation stage of the breeding cycle. We found that NDVI and EVI were better predictors of malleefowl breeding activity than soil moisture and winter rainfall. The model with the lowest Akaike information criterion value contained NDVI averaged over 3 months (June–August) and a 1‐km radius. Malleefowl breeding activity had a strong positive association with NDVI (0.42 ± se 0.03) and a negative association with slope (−0.34 ± se 0.03) and vegetation patch size (−0.23 ± se 0.02). We found the proportion of refugia (top 20% of predicted breeding activity) in protected areas was highly variable, decreasing from 42% in an extreme wet year (2011) to 14% in an extreme drought year (2007). Expanding the reserve network to include refugia predicted to occur in the south of semi‐arid Victoria could improve resilience of malleefowl to climate change. We demonstrate how remotely sensed vegetation indices combined with citizen science data can identify where to protect native vegetation with high, stable productivity. Our approach could be applied to a broad range of species in semi‐arid regions vulnerable to climate change.
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ItemDesign considerations for rapid biodiversity reconnaissance surveys and long-term monitoring to assess the impact of wildfire(WILEY, 2022-03)Abstract Aims Reconnaissance surveys followed by monitoring are needed to assess the impact and response of biodiversity to wildfire. However, post‐wildfire survey and monitoring design are challenging due to the infrequency and unpredictability of wildfire, an urgency to initiate surveys and uncertainty about how species respond. In this article, we discuss key design considerations and quantitative tools available to aid post‐wildfire survey design. Our motivation was to inform the design of rapid surveys for threatened species heavily impacted by the 2019–2020 fires in Australia. Location Global. Methods We discuss a set of best practice design considerations for post‐wildfire reconnaissance surveys across a range of survey objectives. We provide examples that illustrate key design considerations from post‐fire reconnaissance surveys and monitoring programmes from around the world. Results We highlight how the objective of post‐fire surveys drastically influences design decisions (e.g. survey location and timing). We discuss how the unpredictability of wildfire and uncertainty in the response of biodiversity complicate survey design decisions. Main conclusions Surveys should be conducted immediately following wildfire to assess the impact on biodiversity, to ground truth fire severity mapping and to provide a benchmark from which to assess recovery. Where possible, surveys should be conducted at burnt and unburnt sites in regions with historical data so that state variables of interest can be compared with baseline estimates (i.e. BACI design). This highlights the need to have long‐term monitoring programmes already in place and be prepared to modify their design when wildfires occur. There is opportunity to adopt tools from statistics (i.e. power analysis) and conservation planning (i.e. spatial prioritization) to improve survey design. We must anticipate wildfires rather than respond to them reactively as they will occur more frequently due to climate change.
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ItemRapid assessment of the biodiversity impacts of the 2019-2020 Australian megafires to guide urgent management intervention and recovery and lessons for other regions(WILEY, 2022-03)Abstract Aim The incidence of major fires is increasing globally, creating extraordinary challenges for governments, managers and conservation scientists. In 2019–2020, Australia experienced precedent‐setting fires that burned over several months, affecting seven states and territories and causing massive biodiversity loss. Whilst the fires were still burning, the Australian Government convened a biodiversity Expert Panel to guide its bushfire response. A pressing need was to target emergency investment and management to reduce the chance of extinctions and maximise the chances of longer‐term recovery. We describe the approach taken to rapidly prioritise fire‐affected animal species. We use the experience to consider the organisational and data requirements for evidence‐based responses to future ecological disasters. Location Forested biomes of subtropical and temperate Australia, with lessons for other regions. Methods We developed assessment frameworks to screen fire‐affected species based on their pre‐fire conservation status, the proportion of their distribution overlapping with fires, and their behavioural/ecological traits relating to fire vulnerability. Using formal and informal networks of scientists, government and non‐government staff and managers, we collated expert input and data from multiple sources, undertook the analyses, and completed the assessments in 3 weeks for vertebrates and 8 weeks for invertebrates. Results The assessments prioritised 92 vertebrate and 213 invertebrate species for urgent management response; another 147 invertebrate species were placed on a watchlist requiring further information. Conclusions The priority species lists helped focus government and non‐government investment, management and research effort, and communication to the public. Using multiple expert networks allowed the assessments to be completed rapidly using the best information available. However, the assessments highlighted substantial gaps in data availability and access, deficiencies in statutory threatened species listings, and the need for capacity‐building across the conservation science and management sectors. We outline a flexible template for using evidence effectively in emergency responses for future ecological disasters.
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ItemThe conservation impacts of ecological disturbance: Time-bound estimates of population loss and recovery for fauna affected by the 2019-2020 Australian megafires(WILEY, 2022-10-01)Aim: After environmental disasters, species with large population losses may need urgent protection to prevent extinction and support recovery. Following the 2019–2020 Australian megafires, we estimated population losses and recovery in fire-affected fauna, to inform conservation status assessments and management. Location: Temperate and subtropical Australia. Time period: 2019–2030 and beyond. Major taxa: Australian terrestrial and freshwater vertebrates; one invertebrate group. Methods: From > 1,050 fire-affected taxa, we selected 173 whose distributions substantially overlapped the fire extent. We estimated the proportion of each taxon’s distribution affected by fires, using fire severity and aquatic impact mapping, and new distribution mapping. Using expert elicitation informed by evidence of responses to previous wildfires, we estimated local population responses to fires of varying severity. We combined the spatial and elicitation data to estimate overall population loss and recovery trajectories, and thus indicate potential eligibility for listing as threatened, or uplisting, under Australian legislation. Results: We estimate that the 2019–2020 Australian megafires caused, or contributed to, population declines that make 70–82 taxa eligible for listing as threatened; and another 21–27 taxa eligible for uplisting. If so-listed, this represents a 22–26% increase in Australian statutory lists of threatened terrestrial and freshwater vertebrates and spiny crayfish, and uplisting for 8–10% of threatened taxa. Such changes would cause an abrupt worsening of underlying trajectories in vertebrates, as measured by Red List Indices. We predict that 54–88% of 173 assessed taxa will not recover to pre-fire population size within 10 years/three generations. Main conclusions: We suggest the 2019–2020 Australian megafires have worsened the conservation prospects for many species. Of the 91 taxa recommended for listing/uplisting consideration, 84 are now under formal review through national processes. Improving predictions about taxon vulnerability with empirical data on population responses, reducing the likelihood of future catastrophic events and mitigating their impacts on biodiversity, are critical.
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ItemQuantifying the impact of vegetation-based metrics on species persistence when choosing offsets for habitat destruction(WILEY, 2021-04)Developers are often required by law to offset environmental impacts through targeted conservation actions. Most offset policies specify metrics for calculating offset requirements, usually by assessing vegetation condition. Despite widespread use, there is little evidence to support the effectiveness of vegetation-based metrics for ensuring biodiversity persistence. We compared long-term impacts of biodiversity offsetting based on area only; vegetation condition only; area × habitat suitability; and condition × habitat suitability in development and restoration simulations for the Hunter Region of New South Wales, Australia. We simulated development and subsequent offsetting through restoration within a virtual landscape, linking simulations to population viability models for 3 species. Habitat gains did not ensure species persistence. No net loss was achieved when performance of offsetting was assessed in terms of amount of habitat restored, but not when outcomes were assessed in terms of persistence. Maintenance of persistence occurred more often when impacts were avoided, giving further support to better enforce the avoidance stage of the mitigation hierarchy. When development affected areas of high habitat quality for species, persistence could not be guaranteed. Therefore, species must be more explicitly accounted for in offsets, rather than just vegetation or habitat alone. Declines due to a failure to account directly for species population dynamics and connectivity overshadowed the benefits delivered by producing large areas of high-quality habitat. Our modeling framework showed that the benefits delivered by offsets are species specific and that simple vegetation-based metrics can give misguided impressions on how well biodiversity offsets achieve no net loss.