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Environmental context: Understanding how mercury cycles through the environment is crucial for protecting ecosystems and human health. Our study is among the first to measure mercury concentrations in Eucalyptus forest soils and litter and estimate emissions from prescribed burns, addressing a significant gap in current knowledge. These new data enhance our understanding of mercury cycling in Australia and contribute to the global information on the biogeochemical cycle of mercury. Rationale: Research on mercury in Australian soils and litter is sparse. This study aims to address this knowledge gap by investigating mercury pools in soil and litter in a eucalypt forest in Victoria, Australia. Methodology: We analysed total mercury concentrations in O and A horizon soils, and twig, bark and leaf litter. Soil samples were collected from an area affected by a prescribed burn and unburned areas. Additionally, soil samples from the base of tree stems were taken in unburned areas. The organic matter content of all soil samples was also assessed. Results: In unburned soils, mean mercury concentrations at the base of tree stems, in the O-horizon and A horizon were 143 ± 61, 112 ± 71 and 56 ± 30 ng g−1 respectively. In burned soils, mean mercury concentrations in the O and A horizons were 91 ± 63 and 46 ± 19 ng g−1 respectively. Mercury concentrations in leaf, bark and twig litter averaged 71 ± 11, 21 ± 13 and 8 ± 4 ng g−1 respectively. The emission factor was estimated as 0.247 g Hg ha−1. Discussion: The studied sclerophyll forest represents a significant mercury reservoir. Burning did not significantly alter the mercury burden in soil; however, emissions of mercury from litter did occur. This finding underscores the need for more comprehensive research into mercury cycling in Australia and suggests that prescribed burning practices should account for potential mercury emissions. Environmental context. Understanding how mercury cycles through the environment is crucial for protecting ecosystems and human health. Our study is among the first to measure mercury concentrations in Eucalyptus forest soils and litter, and estimate emissions from prescribed burns, addressing a significant gap in current knowledge. These new data enhance our understanding of mercury cycling in Australia and contribute to the global information on the biogeochemical cycle of mercury. (Image credit: Larissa Schneider) This article belongs to the collection: Mercury in the environment. [ABSTRACT FROM AUTHOR]

Protecting forest ecosystems is a critical action for addressing both the climate and biodiversity crises. Effective long-term management of forests requires landscape approaches, but evaluating the management actions is a key challenge. Previous research has suggested evaluation should focus on three interrelated pillars: ecosystem integrity, effective planning, and strong governance. This paper presents a framework for evaluating ecosystem integrity based on the 'Principle, Criteria, Indicator and Verifier' (PCIV) method. The key principle used is ecosystem autopoiesis – the ability of a system for self-generation and maintenance by creating its own parts. Four key criteria are applied, accompanied by a set of nine indicators. Verifiers for each indicator are suggested for which feasible data sources are likely available. The use of the three-pillar framework, including ecosystem integrity, is illustrated using three hypothetical cases representing different forest landscape contexts. Such evaluation can provide practical, consistent, repeatable, and comparable information for stakeholders and decision makers. [ABSTRACT FROM AUTHOR]

Forests are critical for biodiversity conservation and climate change mitigation: reducing emissions, increasing removals, and providing resilient ecosystems with stable long‐term carbon storage. However, evaluating the mitigation effectiveness of forests managed for conservation versus commodity production has been long debated. We assessed factors influencing evaluation of mitigation effectiveness––land area, time horizon, reference level, carbon stock longevity––and tested the outcomes using analyses of carbon dynamics from an Australian ecosystem. Results showed that landscape scale accounting using carbon carrying capacity as the reference level and assessed over a series of time horizons best enables explicit evaluation of mitigation benefits. Time horizons need to differentiate between near‐term emissions reduction targets (2030 and 2050), relative longevity of carbon stocks in different reservoirs, and long‐term impacts on atmospheric CO2 concentration. Greatest mitigation benefits derive from conservation through continued forest growth (52% gain in carbon stock by 2050) and accumulating carbon to attain carbon retention potential (70% gain). Cumulative emissions from harvesting result in permanent elevation of atmospheric CO2 concentration (32 times the annual emission by rotation end). We recommend these time horizons and landscape scales for evaluating forest management to better guide policies and investments for achieving climate mitigation and biodiversity conservation. [ABSTRACT FROM AUTHOR]

The Interior Wetbelt (IWB) of British Columbia includes the globally rare Inland Temperate Rainforest (ITR) that if managed for its substantial carbon (C) stocks can contribute to Canada's Nationally Determined Commitment under the Paris Climate Agreement. We provide spatially explicit estimates of above‐ and belowground live and dead biomass and soil C stocks derived from three sources: (1) government online Vegetation Resources Inventory (VRI); (2) the GlobBiomass spatial dataset; and (3) field plots (n = 27) within old‐growth forests of the ITR. For live aboveground C, we summarize C stocks by elevation classes and decadal forest age. The upper bound on total C densities (above‐ and belowground live and dead biomass and soil C) based on VRI was a maximum of 806 megagrams (Mg) C ha−1. The mean total biomass C density measured in field plots was 583 Mg C ha−1 with a maximum of 1275 Mg C ha−1, which is on par with some of the world's most C‐dense temperate forests. About half the C is in live biomass pools with the rest in dead biomass and soil organic C pools. The mean C density from the VRI over all elevations was 182 Mg C ha−1, with soil organic C ~40% and live tree stems ~27%. Vegetation Resources Inventory estimates were 75% lower than field‐based measurements with the greatest mismatch in areas with the highest C density. Approximately 22% of the IWB has been logged, the majority since 1970s, resulting in live above ground C declining by at least 18%, although this is likely an underestimate. Logging was heavily concentrated in low (<1000 m; 28.3% of elevation zone) to mid‐elevations (1000–2000 m; 20.9%) compared with upper elevations (>2000 m; 1.2%). The region contains underappreciated C stocks that can help Canada meet its climate and conservation targets, but only if there are major forestry reforms that protect C‐dense old‐growth forests, allow degraded forests time to recover the logging‐related C debt, and improve monitoring of C stocks and stock changes. [ABSTRACT FROM AUTHOR]

The Interior Wetbelt (IWB) of British Columbia, which includes the globally rare Inland Temperate Rainforest (ITR), contains primary forests poorly attributed and neglected in conservation planning. We evaluated the IWB and ITR using four IUCN Red List of Ecosystems Criteria: geographic distribution, environmental degradation (abiotic and biotic factors), and likelihood of ecosystem collapse. Clearcut logging (3.2M ha) represented 57% of all anthropogenic disturbances, reducing potential primary forest by 2.7 million ha (28%) for the IWB and 524,003 ha (39%) for the ITR. Decadal logging rates nearly doubled from 5.3% to 10.2% from 1970s--2000s. Core areas (buffered by 100-m from roads and developments) declined by 70% to 95% for the IWB and ITR, respectively. Vulnerable was assigned to karst, the only abiotic factor assessed, because it was associated with rare plants. For biotic factors, Old-Growth Birds were Vulnerable, Southern Woodland Caribou (Rangifer tarandus caribou) habitat and Sensitive Fish were Endangered, and Old-Growth Lichens habitat was Critical. Overall, the IWB was ranked as Endangered and the ITR as Critical with core area collapse possible within 9 to 18 years for the ITR, considered one of the world's most imperiled temperate rainforests. [ABSTRACT FROM AUTHOR]

Since 2009, the Canadian and Alberta governments have been developing monitoring plans for surface water quality and quantity of the lower Athabasca River and its tributaries (2010–2013). The objectives of the present study to the fish monitoring program were to 1) assess the current status of fish in a tributary of the lower Athabasca River, 2) identify existing differences between upstream reference and within the oil sands deposit exposure sites, and 3) identify trends/changes in fish performance indicators relative to historical studies. The present study examines the fish performance indicators in slimy sculpin (Cottus cognatus) in the Steepbank River, Alberta, in terms of growth, gonad size, condition, and hepatic 7‐ethoxyresorufin‐O‐deethylase (EROD) activity as an indicator of exposure to oil‐sands‐related compounds. The sampling program followed historical sampling methods (1999–2000) to provide comparable data over time with an additional upstream site (n = 2) added as development progressed. Consistent changes were documented in sculpin collected from downstream sections of the Steepbank River within the oil sands deposit (n = 2) in 2010 through 2013. Sculpin demonstrated increased liver size with corresponding induction of EROD activity consistent with historical data and reductions in energy investment relative to reproductive development and gonadal steroid production capacity. There was no consistent evidence of changes in fish performance indicators with increased surface mining development, particularly adjacent to the Steepbank River Mid site. Although physical development in the Steepbank watershed has increased over the last 15 yr, these results are consistent with historical data suggesting that the magnitude of the response in the aquatic environment adjacent to the development has not changed. Environ Toxicol Chem 2020;39:396–409. © 2019 SETAC [ABSTRACT FROM AUTHOR]